WorldWideScience

Sample records for building thermal simulation

  1. Thermal comfort in residential buildings: Comfort values and scales for building energy simulation

    Energy Technology Data Exchange (ETDEWEB)

    Peeters, Leen; D' haeseleer, William [Division of Applied Mechanics and Energy Conversion, University of Leuven (K.U.Leuven), Celestijnenlaan 300 A, B-3001 Leuven (Belgium); Dear, Richard de [Division of Environmental and Life Sciences, Macquarie University, Sydney (Australia); Hensen, Jan [Faculty of Architecture, Building and Planning, Technische Universiteit Eindhoven, Vertigo 6.18, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2009-05-15

    Building Energy Simulation (BES) programmes often use conventional thermal comfort theories to make decisions, whilst recent research in the field of thermal comfort clearly shows that important effects are not incorporated. The conventional theories of thermal comfort were set up based on steady state laboratory experiments. This, however, is not representing the real situation in buildings, especially not when focusing on residential buildings. Therefore, in present analysis, recent reviews and adaptations are considered to extract acceptable temperature ranges and comfort scales. They will be defined in an algorithm, easily implementable in any BES code. The focus is on comfortable temperature levels in the room, more than on the detailed temperature distribution within that room. (author)

  2. Building high-accuracy thermal simulation for evaluation of thermal comfort in real houses

    OpenAIRE

    Nguyen, Hoaison; Makino, Yoshiki; Lim, Azman Osman; TAN, Yasuo; Shinoda, Yoichi

    2013-01-01

    Thermal comfort is an essential aspect for the control and verification of many smart home services. In this research, we design and implement simulation which models thermal environment of a smart house testbed. Our simulation can be used to evaluate thermal comfort in various conditions of home environment. In order to increase the accuracy of the simulation, we measure thermal-related parameters of the house such as temperature, humidity, solar radiation by the use of sensors and perform p...

  3. Combining building thermal simulation methods and LCA methods

    DEFF Research Database (Denmark)

    Pedersen, Frank; Hansen, Klaus; Wittchen, Kim Bjarne;

    2008-01-01

    of buildings (as expressed in EU Directive 2002/91/EC), may in the future be supplemented by requirements to the environmental impact of buildings. This can be seen by the fact that EU recently has given EN mandate to prepare standards for environmental assessment of buildings (CEN/TC 350)....

  4. Ventilated buildings optimisation by using a coupled thermal-airflow simulation program

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan; Østergaard, Poul Alberg; Remmen, Arne

    2011-01-01

    This work shows the optimization of natural ventilation within buildings at the stage of design and behaviour of the occupants. An evaluation is done by coupled multizone air modelling and thermal building simulation by using a deterministic set of input factors comprising among others climate......, local environment, building characteristics, building systems, behaviour of occupants, heat loads. Selected deterministic input factors were varied to generate additional information applied in an optimization loop. With that, it is found that the optimal solution depends to a great deal...... on the possibility of combined optimization of the behaviour of occupants with a lesser extent of the design building....

  5. The analysis of thermal comfort requirements through the simulation of an occupied building.

    Science.gov (United States)

    Thellier, F; Cordier, A; Monchoux, F

    1994-05-01

    Building simulation usually focuses on the study of physical indoor parameters, but we must not forget the main aim of a house: to provide comfort to the occupants. This study was undertaken in order to build a complete tool to model thermal behaviour that will enable the prediction of thermal sensations of humans in a real environment. A human thermoregulation model was added to TRNSYS, a building simulation program. For our purposes, improvements had to be made to the original physiological model, by refining the calculation of all heat exchanges with the environment and adding a representation of clothes. This paper briefly describes the program, its modifications, and compares its results with experimental ones. An example of potential use is given, which points out the usefulness of such models in seeking the best solutions to reach optimal environmental conditions for global, and specially local comfort, of building occupants. PMID:8206050

  6. Simulation of thermal indoor climate in buildings by using human Projected Area Factors

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik

    2009-01-01

    measure for thermal environ-ment. The operative temperature is a function of the air temperature, the mean radiant temperature and the relative air velocity. However, in many programs for calculation of energy consumption and thermal indoor climate the model for calculating the mean radiant temperature......Nowadays many new and old buildings in Denmark have large glass surfaces. This is a consequence of the technical development of windows with low U-values that has made it possible to build houses with windows from floor to ceiling in northern climates. On the other hand if one is sitting close...... to these large windows on a cold winter day it is recognized that this can cause thermal discomfort. The calculation of this discomfort needs to be taken properly into account in the simulation of the thermal indoor climate and energy consumption of the rooms. The operative temperature can be used as a simple...

  7. Demand Shifting With Thermal Mass in Large Commercial Buildings:Field Tests, Simulation and Audits

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Peng; Haves, Philip; Piette, Mary Ann; Zagreus, Leah

    2005-09-01

    The principle of pre-cooling and demand limiting is to pre-cool buildings at night or in the morning during off-peak hours, storing cooling in the building thermal mass and thereby reducing cooling loads and reducing or shedding related electrical demand during the peak periods. Cost savings are achieved by reducing on-peak energy and demand charges. The potential for utilizing building thermal mass for load shifting and peak demand reduction has been demonstrated in a number of simulation, laboratory, and field studies (Braun 1990, Ruud et al. 1990, Conniff 1991, Andresen and Brandemuehl 1992, Mahajan et al. 1993, Morris et al. 1994, Keeney and Braun 1997, Becker and Paciuk 2002, Xu et al. 2003). This technology appears to have significant potential for demand reduction if applied within an overall demand response program. The primary goal associated with this research is to develop information and tools necessary to assess the viability of and, where appropriate, implement demand response programs involving building thermal mass in buildings throughout California. The project involves evaluating the technology readiness, overall demand reduction potential, and customer acceptance for different classes of buildings. This information can be used along with estimates of the impact of the strategies on energy use to design appropriate incentives for customers.

  8. Climate classification for the simulation of thermally activated building systems (TABS)

    DEFF Research Database (Denmark)

    Behrendt, Benjamin; Christensen, Jørgen Erik

    2013-01-01

    Thermally activated building systems (TABS) provide high temperature cooling and low temperature heating which has a better efficiency compared to traditional heating and cooling solutions. Additionally the moderate required temperature levels for heating and cooling create the opportunity to use...

  9. Critical Simulation Based Evaluation of Thermally Activated Building Systems (TABS) Design Models

    OpenAIRE

    Basu, Chandrayee

    2012-01-01

    Thermally Activated Building Systems (TABS) is a recognized low-energy HVAC system. Sizing of these systems is complex due to their slow thermal response. Limited cooling capacity of these systems and inadequacy of conventional sizing method, that assumes high factor of safety, is preventing early adoption of these systems. TABS, however, is proven to be energy-efficient and capable of preserving comfort in several commercial buildings of Europe. There is, however no comprehensive case study ...

  10. Simulated thermal energy demand and actual energy consumption in refurbished and non-refurbished buildings

    Science.gov (United States)

    Ilie, C. A.; Visa, I.; Duta, A.

    2016-08-01

    The EU legal frame imposes the Nearly Zero Energy Buildings (nZEB) status to any new public building starting with January 1st, 2019 and for any other new building starting with 2021. Basically, nZEB represents a Low Energy Building (LEB) that covers more than half of the energy demand by using renewable energy systems installed on or close to it. Thus, two steps have to be followed in developing nZEB: (1) reaching the LEB status through state- of-the art architectural and construction solutions (for the new buildings) or through refurbishing for the already existent buildings, followed by (2) implementing renewables; in Romania, over 65% of the energy demand in a building is directly linked to heating, domestic hot water (DHW), and - in certain areas - for cooling. Thus, effort should be directed to reduce the thermal energy demand to be further covered by using clean and affordable systems: solar- thermal systems, heat pumps, biomass, etc. or their hybrid combinations. Obviously this demand is influenced by the onsite climatic profile and by the building performance. An almost worst case scenario is approached in the paper, considering a community implemented in a mountain area, with cold and long winters and mild summers (Odorheiul Secuiesc city, Harghita county, Romania). Three representative types of buildings are analysed: multi-family households (in blocks of flats), single-family houses and administrative buildings. For the first two types, old and refurbished buildings were comparatively discussed.

  11. A Comparison between CODYRUN and TRNSYS, simulation models for thermal buildings behaviour

    OpenAIRE

    Lucas, Franck; Mara, Thierry A.; Garde, Francois; Garde, François; Boyer, Harry

    1998-01-01

    International audience Simulation codes of thermal behaviour could significantly improve housing construction design. Among the existing software, CODYRUN and TRNSYS are calculations codes of different conceptions. CODYRUN is exclusively dedicated to housing thermal behaviour, whereas TRNSYS is more generally used on any thermal system. The purpose of this article is to compare these two instruments in two different conditions . We will first modelize a mono-zone test cell, and analyse the...

  12. Modeling Data Center Building Blocks for Energy-efficiency and Thermal Simulations

    OpenAIRE

    Vor Dem Berge, Micha; Da Costa, Georges; Jarus, Mateusz; Oleksiak, Ariel; Piatek, Wojciech; Volk, Eugen

    2013-01-01

    In this paper we present a concept and specification of Data Center Efficiency Building Blocks (DEBBs), which represent hardware components of a data center complemented by descriptions of their energy efficiency. Proposed building blocks contain hardware and thermodynamic models that can be applied to simulate a data center and to evaluate its energy efficiency. DEBBs are available in an open repository being built by the CoolEmAll project. In the paper we illustrate the concept by an exampl...

  13. Simulation of energy use, human thermal comfort and office work performance in buildings with moderately drifting operative temperatures

    DEFF Research Database (Denmark)

    Kolarik, Jakub; Toftum, Jørn; Olesen, Bjarne W.;

    2011-01-01

    ) supplemented with CAV ventilation. Simulations comprised moderate, hot–dry and hot–humid climate. Heavy and light wall construction and two orientations of the building (east–west and north–south) were considered. Besides the energy use, also capability of examined systems to keep a certain level of thermal......Annual primary energy use in a central module of an office building consisting of two offices separated with a corridor was estimated by means of dynamic computer simulations. The simulations were conducted for conventional all-air VAV ventilation system and thermo active building system (TABS...... comfort was examined. The results showed that with the moderate climate, the TABS decreased the primary energy use by about 16% as compared with the VAV. With hot–humid climate, the portion of the primary energy saved by TABS was ca. 50% even with the supply air dehumidification taken into account...

  14. Simulation of thermal behavior of residential buildings using fuzzy active learning method

    Directory of Open Access Journals (Sweden)

    Masoud Taheri Shahraein

    2015-01-01

    Full Text Available In this paper, a fuzzy modeling technique called Modified Active Learning Method (MALM was introduced and utilized for fuzzy simulation of indoor and inner surface temperatures in residential buildings using meteorological data and its capability for fuzzy simulation was compared with other studies. The case studies for simulations were two residential apartments in the Fakouri and Rezashahr neighborhoods of Mashhad, Iran. The hourly inner surface and indoor temperature data were accumulated during measurements taken in 2010 and 2011 in different rooms of the apartments under heating and natural ventilation conditions. Hourly meteorological data (dry bulb temperature, wind speed and direction and solar radiation were measured by a meteorological station and utilized with zero to three hours lags as input variables for the simulation of inner surface and indoor temperatures. The results of simulations demonstrated the capability of MALM to be used for nonlinear fuzzy simulation of inner surface and indoor temperatures in residential apartments.

  15. Dynamic thermal simulation of ground heat exchangers for renewable heating of buildings

    OpenAIRE

    Gan, Guohui

    2016-01-01

    The temperature of deep soil is relatively stable throughout a year and the thermal energy stored in soil can be used to provide renewable heat or coolth for a building. A ground heat exchanger is required to transfer heat between the fluid in the heat exchanger and surrounding soil. The control volume method is used to solve the equations for coupled heat and moisture transfer in soil and the dynamic interactions between the heat exchanger, soil and atmosphere. The method is used for numeric...

  16. Simulation and experimental study of thermal performance of a building roof with a phase change material (PCM)

    Indian Academy of Sciences (India)

    A Mannivannan; M T Jaffarsathiq Ali

    2015-12-01

    Latent heat storage in a phase change material (PCM) is very attractive because of its high-energy storage density and its isothermal behaviour during the phase change process. Low thermal conductivity of the walls and roof reduces the heat gain at a steady state condition. Chloride hexahydrate (CaCl26H2O) as a phase change material (PCM) for a room was proposed in this paper to control the indoor air temperature for a better thermal comfort for human beings. Building concrete roof with vertical cylindrical hole of 0.5 $\\times$ 0.5 m and array of 3 $\\times$ 3 filled with phase change material (PCM) was considered for analysis. A detailed thermal analysis was carried by both simulation and experimental study. Results showed that this type of PCM room can decrease the indoor air temperature fluctuation by a maximum of 4°C.

  17. Thermal-comfort analysis and simulation for various low-energy cooling-technologies applied to an office building in a subtropical climate

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Ashfaque Ahmed; Rasul, M.G.; Khan, M.M.K. [College of Engineering and the Built Environment, Faculty of Sciences, Engineering and Health, Central Queensland University, Rockhampton, Qld 4702 (Australia)

    2008-06-15

    Simulation of buildings' thermal-performances is necessary to predict comfort of the occupants in buildings and to identify alternate cooling control-systems for achieving better indoor thermal environments. An analysis and prediction of thermal-comfort using DesignBuilder, based on the state-of-the-art building performance simulation software EnergyPlus, is carried out in an air-conditioned multi-storeyed building in the city of Rockhampton in Central Queensland, Australia. Rockhampton is located in a hot humid-region; therefore, indoor thermal-comfort is strongly affected by the outdoor climate. This study evaluates the actual thermal conditions of the Information Technology Division (ITD) building at Central Queensland University during winter and summer seasons and identifies the thermal comfort level of the occupants using low-energy cooling technologies namely, chilled ceiling (CC), economiser usages and pre-cooling. The Fanger comfort-model, Pierce two-node model and KSU two-node model were used to predict thermal performance of the building. A sophisticated building-analysis tool was integrated with the thermal comfort models for determining appropriate cooling-technologies for the occupants to be thermally comfortable while achieving sufficient energy savings. This study compares the predicted mean-vote (PMV) index on a seven-point thermal-sensation scale, calculated using the effective temperature and relative humidity for those cooling techniques. Simulated results show that systems using a chilled ceiling offer the best thermal comfort for the occupants during summer and winter in subtropical climates. The validity of the simulation results was checked with measured values of temperature and humidity for typical days in both summer and winter. The predicted results show a reasonable agreement with the measured data. (author)

  18. Thermal evaluation of buildings

    OpenAIRE

    Barajas, Luís M; Roset Calzada, Jaime; La Ferla, Giuseppe

    2015-01-01

    To COST ACTION TU 1104 "Smart Energy Regions" Prof. Aleksandra Djukic and Prof. Aleksandra Krstic-Furundzic of the Faculty of Architecture of the University of Belgrade, Serbia, that gave us the opportunity of be part of the training school imparted from Monday 20th to Thursday 23rd April 2015, where we can teach the topic. The convenience of the use of environmental building evaluation tools, to know design conditions and thermal behavior, by using bioclimatic strategies fo...

  19. Modeling and simulation to determine the potential energy savings by implementing cold thermal energy storage system in office buildings

    International Nuclear Information System (INIS)

    Highlights: • Simulating the CTES system behavior based on Malaysian climate. • Almost 65% of power is used for cooling for cooling the office buildings, every day. • The baseline shows an acceptable match with real data from the fieldwork. • Overall, the energy used for full load storage is much than the conventional system. • The load levelling storage strategy has 3.7% lower energy demand. - Abstract: In Malaysia, air conditioning (AC) systems are considered as the major energy consumers in office buildings with almost 57% share. During the past decade, cold thermal energy storage (CTES) systems have been widely used for their significant economic benefits. However, there were always doubts about their energy saving possibilities. The main objective of the present work is to develop a computer model to determine the potential energy savings of implementing CTES systems in Malaysia. A case study building has been selected to determine the energy consumption pattern of an office building. In the first step the building baseline model was developed and validated with the recorded data from the fieldwork. Once the simulation results reach an acceptable accuracy, different CTES system configuration was added to the model to predict their energy consumption pattern. It was found that the overall energy used by the full load storage strategy is considerably more than the conventional system. However, by applying the load leveling storage strategy, and considering its benefits to reduce the air handling unit size and reducing the pumping power, the overall energy usage was almost 4% lower than the non-storage system. Although utilizing CTES systems cannot reduce the total energy consumption considerably, but it has several outstanding benefits such as cost saving, bringing balance in the grid system, reducing the overall fuel consumption in the power plants and consequently reducing to total carbon footprint

  20. Simulated performance of the Thermo Active Building System (TABS) with respect to the provided thermal comfort and primary energy use

    DEFF Research Database (Denmark)

    Kolarik, Jakub; Olesen, Bjarne W.; Toftum, Jørn

    2009-01-01

    The central module of an office building conditioned by a Thermo Active Building System (TABS) coupled with constant volume ventilation was evaluated by means of dynamic computer simulations. Additionally, the same building model was simulated with a conventional all air VAV ventilation system for...

  1. Structured building model reduction toward parallel simulation

    Energy Technology Data Exchange (ETDEWEB)

    Dobbs, Justin R. [Cornell University; Hencey, Brondon M. [Cornell University

    2013-08-26

    Building energy model reduction exchanges accuracy for improved simulation speed by reducing the number of dynamical equations. Parallel computing aims to improve simulation times without loss of accuracy but is poorly utilized by contemporary simulators and is inherently limited by inter-processor communication. This paper bridges these disparate techniques to implement efficient parallel building thermal simulation. We begin with a survey of three structured reduction approaches that compares their performance to a leading unstructured method. We then use structured model reduction to find thermal clusters in the building energy model and allocate processing resources. Experimental results demonstrate faster simulation and low error without any interprocessor communication.

  2. Modeling a Naturally Ventilated Double Skin Façade with a Building Thermal Simulation Program

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Kalyanova, Olena; Heiselberg, Per

    2008-01-01

    The use of Double Skin Façade (DSF) has increased during the last decade. There are many reasons for this including e.g. aesthetics, sound insulation, improved indoor environment and energy savings. However, the influence on the indoor environment and energy consumption are very difficult...... to predict. This is manly due to the very transient and complex air flow in the naturally ventilated double skin façade cavity. In this paper the modelling of the DSF using a thermal simulation program, BSim, is discussed. The simulations are based on the measured weather boundary conditions......, and the simulation results are compared to the measurement results like energy consumption for cooling, air temperature, temperature gradient and mass flow rate in the DSF cavity, etc. Details about the measurements are reported in \\Kalyanova et al. 2008\\. The thermal simulation program does not at the moment...

  3. Economic analysis of energy-saving renovation measures for urban existing residential buildings in China based on thermal simulation and site investigation

    International Nuclear Information System (INIS)

    Energy-saving renovations of existing residential buildings have proven to be very helpful in alleviating the pressure of energy shortages and CO2 emission, but an economic analysis of the measures by using a life cycle cost (LCC) method is very important and necessary to determine whether to implement them or not. Based on thermal simulation and site investigation, the paper uses one urban existing residential building in Hangzhou city of China as the subject building, and analyzes the economic benefits from the energy-saving renovation measures through the LCC method. The findings clearly show that the investigation of the factual electricity consumption of the subject building is very important to predict accurately the energy-saving effects and financial benefits of the measures for the building, because of the great discrepancy between in fact and in thermal simulation of the heating and cool loads, and the too cheap electricity price may hamper the development of energy-saving implementations in residential sector in China

  4. Integrating CFD and building simulation

    DEFF Research Database (Denmark)

    Bartak, M.; Beausoleil-Morrison, I.; Clarke, J.A.;

    2002-01-01

    To provide practitioners with the means to tackle problems related to poor indoor environments, building simulation and computational 3uid dynamics can usefully be integrated within a single computational framework. This paper describes the outcomes from a research project sponsored by the European...... Commission, which furthered the CFD modelling aspects of the ESP-r system. The paper summarises the form of the CFD model, describes the method used to integrate the thermal and 3ow domains and reports the outcome from an empirical validation exercise. © 2002 Published by Elsevier Science Ltd....

  5. Modeling a Naturally Ventilated Double Skin Façade with a Building Thermal Simulation Program

    DEFF Research Database (Denmark)

    Jensen, Rasmus Lund; Kalyanova, Olena; Heiselberg, Per

    2008-01-01

    The use of Double Skin Façade (DSF) has increased during the last decade. There are many reasons for this including e.g. aesthetics, sound insulation, improved indoor environment and energy savings. However, the influence on the indoor environment and energy consumption are very difficult......, and the simulation results are compared to the measurement results like energy consumption for cooling, air temperature, temperature gradient and mass flow rate in the DSF cavity, etc. Details about the measurements are reported in \\Kalyanova et al. 2008\\. The thermal simulation program does not at the moment...... include a special model to simulate the DSF. However, the results show that it was possible to predict the energy flow, temperature distribution and airflow in the DSF. The good agreement between the measured and simulated results was unfortunately very sensitive to the model. This implies that without...

  6. CFD Simulation of a Concrete Cubicle to Analyze the Thermal Effect of Phase Change Materials in Buildings

    Directory of Open Access Journals (Sweden)

    José L. Míguez

    2012-06-01

    Full Text Available In this work, a CFD-based model is proposed to analyse the effect of phase change materials (PCMs on the thermal behaviour of the walls of a cubicle exposed to the environment and on the resistance of the walls to climate changes. The effect of several days of exposure to the environment was simulated using the proposed method. The results of the simulation are compared with experimental data to contrast the models. The effects of exposure on the same days were simulated for several walls of a cubicle made of a mixture of concrete and PCM. The results show that the PCM stabilizes temperatures within the cubicle and decreases energy consumption of refrigeration systems.

  7. Use of model reduction techniques for a simulation code in building thermal behaviour modelling; Integration de la reduction de modele a un code de simulation hygro-thermo-aeraulique de batiments

    Energy Technology Data Exchange (ETDEWEB)

    Berthomieu, Th.; Boyer, H. [Universite de la Reunion (France). Laboratoire de Genie Industriel

    2004-02-01

    It is possible at present to perform complex thermal studies, integrating various thermal sources and for various buildings, using energetic software. It is always interesting to simplify the calculation process with numerical reduction techniques. In this paper a reduction technique using the decomposition of a complex system in elementary components linked each other by simple relations is presented. This reduction is performed in simulation code Codyrum, which can be used for research purpose of for design help. The results of simulation are compared with experimental results. (authors)

  8. Power Admission Control with Predictive Thermal Management in Smart Buildings

    DEFF Research Database (Denmark)

    Yao, Jianguo; Costanzo, Giuseppe Tommaso; Zhu, Guchuan;

    2015-01-01

    This paper presents a control scheme for thermal management in smart buildings based on predictive power admission control. This approach combines model predictive control with budget-schedulability analysis in order to reduce peak power consumption as well as ensure thermal comfort. First...... appliances. The performance of the proposed control scheme is assessed by simulation based on the thermal dynamics of a real eight-room office building located at Danish Technical University....

  9. Whole-building Hygrothermal Simulation Model

    DEFF Research Database (Denmark)

    Rode, Carsten; Grau, Karl

    2003-01-01

    An existing integrated simulation tool for dynamic thermal simulation of building was extended with a transient model for moisture release and uptake in building materials. Validation of the new model was begun with comparison against measurements in an outdoor test cell furnished with single...... materials. Almost quasi-steady, cyclic experiments were used to compare the indoor humidity variation and the numerical results of the integrated simulation tool with the new moisture model. Except for the case with chipboard as furnishing, the predictions of indoor humidity with the detailed model were...

  10. A simple method to estimate the urban heat island intensity in data sets used for the simulation of the thermal behaviour of buildings

    Directory of Open Access Journals (Sweden)

    Uwe Wienert

    2013-04-01

    Full Text Available Test Reference Years (TRY are data sets tailored for use in the context of simulations with respect to the thermal behaviour of buildings. They are based on measurements and observations from weather stations of the German Meteorological Service (Deutscher Wetterdienst, DWD and represent the climate conditions of a larger area with an order of magnitude of 100 km x 100 km. The data sets cannot, however, be readily applied to urban areas. The air temperature as one of the most important meteorological elements for the building-related simulations frequently is subject to an increase with respect to the conditions outside the city area due to what is called the urban heat island effect. Numerous field measurements have led to the development of empirical relations to assess the urban temperature modification. These relations were implemented in a straightforward method. It applies a set of easily accessible parameters in a combination of different empirical formulae to derive an estimate of the urban air temperature modification. An intercomparison of calculated versus measured air temperature data showed that this method might yield a realistic representation of the urban heat island intensity.

  11. Analysis of a natural exhaust fan in a building of houses through thermal simulations and CFD; Analisis de un sistema de ventilacion natural en un edificio de viviendas a traves de simulaciones termicas y CFD

    Energy Technology Data Exchange (ETDEWEB)

    Bueno, B.; Cejudo, J.; Carrillo, A.

    2008-07-01

    Computational fluid dynamics (CFD) application to building energy simulation (STE) allows better modelling of indoor air performance and therefore it can be used to optimize the design of natural ventilation systems. In this paper, a natural ventilation system based on thermal chimney applied to a residential building is analyzed. Energy Plus simulations are applied to an apartment and results are coupled to CFD simulations to determine ventilation rates and study convection in the space. CFD simulations are also applied to evaluate indoor air distribution and study how ventilation rate is affected by the pressure drop at ventilation grilles. (Author)

  12. Simulating Building Fires for Movies

    Science.gov (United States)

    Rodriguez, Ricardo C.; Johnson, Randall P.

    1987-01-01

    Fire scenes for cinematography staged at relatively low cost in method that combines several existing techniques. Nearly realistic scenes, suitable for firefighter training, produced with little specialized equipment. Sequences of scenes set up quickly and easily, without compromising safety because model not burned. Images of fire, steam, and smoke superimposed on image of building to simulate burning of building.

  13. Detailed weather data generator for building simulations

    CERN Document Server

    Adelard, L; Garde, F; Gatina, J -C

    2012-01-01

    Thermal buildings simulation softwares need meteorological files in thermal comfort, energetic evaluation studies. Few tools can make significant meteorological data available such as generated typical year, representative days, or artificial meteorological database. This paper deals about the presentation of a new software, RUNEOLE, used to provide weather data in buildings applications with a method adapted to all kind of climates. RUNEOLE associates three modules of description, modelling and generation of weather data. The statistical description of an existing meteorological database makes typical representative days available and leads to the creation of model libraries. The generation module leads to the generation of non existing sequences. This software tends to be usable for the searchers and designers, by means of interactivity, facilitated use and easy communication. The conceptual basis of this tool will be exposed and we'll propose two examples of applications in building physics for tropical hu...

  14. Building America House Simulation Protocols

    Energy Technology Data Exchange (ETDEWEB)

    Hendron, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Engebrecht, Cheryn [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2010-09-01

    The House Simulation Protocol document was developed to track and manage progress toward Building America's multi-year, average whole-building energy reduction research goals for new construction and existing homes, using a consistent analytical reference point. This report summarizes the guidelines for developing and reporting these analytical results in a consistent and meaningful manner for all home energy uses using standard operating conditions.

  15. Duct thermal performance models for large commercial buildings

    Energy Technology Data Exchange (ETDEWEB)

    Wray, Craig P.

    2003-10-01

    Despite the potential for significant energy savings by reducing duct leakage or other thermal losses from duct systems in large commercial buildings, California Title 24 has no provisions to credit energy-efficient duct systems in these buildings. A substantial reason is the lack of readily available simulation tools to demonstrate the energy-saving benefits associated with efficient duct systems in large commercial buildings. The overall goal of the Efficient Distribution Systems (EDS) project within the PIER High Performance Commercial Building Systems Program is to bridge the gaps in current duct thermal performance modeling capabilities, and to expand our understanding of duct thermal performance in California large commercial buildings. As steps toward this goal, our strategy in the EDS project involves two parts: (1) developing a whole-building energy simulation approach for analyzing duct thermal performance in large commercial buildings, and (2) using the tool to identify the energy impacts of duct leakage in California large commercial buildings, in support of future recommendations to address duct performance in the Title 24 Energy Efficiency Standards for Nonresidential Buildings. The specific technical objectives for the EDS project were to: (1) Identify a near-term whole-building energy simulation approach that can be used in the impacts analysis task of this project (see Objective 3), with little or no modification. A secondary objective is to recommend how to proceed with long-term development of an improved compliance tool for Title 24 that addresses duct thermal performance. (2) Develop an Alternative Calculation Method (ACM) change proposal to include a new metric for thermal distribution system efficiency in the reporting requirements for the 2005 Title 24 Standards. The metric will facilitate future comparisons of different system types using a common ''yardstick''. (3) Using the selected near-term simulation approach

  16. Method for simulating predictive control of building systems operation in the early stages of building design

    DEFF Research Database (Denmark)

    Petersen, Steffen; Svendsen, Svend

    2011-01-01

    A method for simulating predictive control of building systems operation in the early stages of building design is presented. The method uses building simulation based on weather forecasts to predict whether there is a future heating or cooling requirement. This information enables the thermal...... control systems of the building to respond proactively to keep the operational temperature within the thermal comfort range with the minimum use of energy. The method is implemented in an existing building simulation tool designed to inform decisions in the early stages of building design through...... parametric analysis. This enables building designers to predict the performance of the method and include it as a part of the solution space. The method furthermore facilitates the task of configuring appropriate building systems control schemes in the tool, and it eliminates time consuming manual...

  17. Residential building thermal performance energy efficiency in Yangtze River basin

    Institute of Scientific and Technical Information of China (English)

    王厚华; 庄燕燕; 吴伟伟

    2009-01-01

    Using energy consumption software VisualDOE4.0,simulation was carried out on the energy consumption of a typical residential building in Yangtze River basin,with a focus on thermal performance of envelope each component and application of total heating recovery equipment. The effects of thermal performance of building envelope each component on energy efficiency ratio were analyzed. Comprehensive measures schemes of energy saving were designed by the orthogonal experiment. The energy efficiency ratios of different envelopes combination schemes were gained. Finally,the optimize combination scheme was confirmed. With the measurement dates,the correctness of the simulation dates was completely verified.

  18. Thermally activated building systems in context of increasing building energy efficiency

    Directory of Open Access Journals (Sweden)

    Stojanović Branislav V.

    2014-01-01

    Full Text Available One of the possible ways to provide heating to the building is to use thermally activated building systems. This type of heating, besides providing significant increase in building energy efficiency, allows using low-temperature heating sources. In this paper, special attention is given to opaque part of the building façade with integrated thermally activated building systems. Due to fact that this type of system strongly depends on temperature of this construction-thermal element and type and thickness of other materials of the façade, influence of these parameters on energy efficiency was analyzed in this paper. Since the simplest and most promising way of using geothermal energy is to use it directly, for our analysis this source of energy was selected. Building energy needs for heating were obtained for real residential multi-family building in Serbia by using EnergyPlus software. The building with all necessary input for simulation was modeled in Google SketchUp with aid of Open Studio Plug-in. Obtained results were compared with measured heating energy consumption. The results show that thermally activated building systems represent good way to increase building energy efficiency and that applying certain temperatures within this element, low-energy house standard can be achieved.

  19. Directional Thermal Emitter Simulation

    OpenAIRE

    Dhaka, Shailja; Sakr, Enas Said; Bermel, Peter

    2015-01-01

    The development of renewable energy sources has attracted increasing interest because of negative externalities associated with fossil fuel use. Thermophotovoltaics is a promising technology, in which a thermal emitter radiates photons which are directly converted into electricity using a photovoltaic diode. However, blackbody emission includes a broad range of wavelengths, but only higher energy photons can be converted into electricity. Thus, tailoring the selectivity of thermal emission is...

  20. Field test of a thermal active building system (tabs) in an office building in Denmark

    DEFF Research Database (Denmark)

    Raimondo, Daniela; Olesen, Bjarne W.; Corgnati, Stefano P.

    2013-01-01

    an experimental study in an office building in Denmark where cooling in summer is provided by thermally activated building systems (TABS). Indoor climate quality evaluation, cooling system performance and energy consumption for a specific room were analyzed with different levels of internal gains. The experiments...... in the pipes of the hydronic system, and energy consumption of the chillers were monitored. The performance of this test room was also analyzed by the dynamic building simulation tool Energy Plus. The paper includes a comparison between experimental collected data and simulation results. Besides the paper show...

  1. Thermal comfort assessment of buildings

    CERN Document Server

    Carlucci, Salvatore

    2013-01-01

    A number of metrics for assessing human thermal response to climatic conditions have been proposed in scientific literature over the last decades. They aim at describing human thermal perception of the thermal environment to which an individual or a group of people is exposed. More recently, a new type of “discomfort index” has been proposed for describing, in a synthetic way, long-term phenomena. Starting from a systematic review of a number of long-term global discomfort indices, they are then contrasted and compared on a reference case study in order to identify their similarities and differences and strengths and weaknesses. Based on this analysis, a new short-term local discomfort index is proposed for the American Adaptive comfort model. Finally, a new and reliable long-term general discomfort index is presented. It is delivered in three versions and each of them is suitable to be respectively coupled with the Fanger, the European Adaptive and the American Adaptive comfort models.

  2. Evolution of CODYRUN from thermal simulation to coupled thermal and daylight simulation software

    OpenAIRE

    Boyer, Harry; Fakra, Ali Hamada; Miranville, Frédéric; Malet-Damour, Bruno; Guichard, Stéphane; Lauret, Philippe

    2014-01-01

    International audience CODYRUN is a multi-zone software integrating thermal building simulation, airflow, and pollutant transfer. Described in numerous publications, this software was originally used forthe passive designof buildings, both for research and teaching purposes.In this context, the data treated were mainly concerned with volumes (zones), surfaces and thicknesses (walls and windows), materials, and systems, with the aim to determine temperatures, heat fluxes,energy consumed, ai...

  3. Computational Fluid Dynamics and Building Energy Performance Simulation

    DEFF Research Database (Denmark)

    Nielsen, Peter V.; Tryggvason, Tryggvi

    An interconnection between a building energy performance simulation program and a Computational Fluid Dynamics program (CFD) for room air distribution will be introduced for improvement of the predictions of both the energy consumption and the indoor environment. The building energy performance...... simulation program requires a detailed description of the energy flow in the air movement which can be obtained by a CFD program. The paper describes an energy consumption calculation in a large building, where the building energy simulation program is modified by CFD predictions of the flow between three...... program and a building energy performance simulation program will improve both the energy consumption data and the prediction of thermal comfort and air quality in a selected area of the building....

  4. Green Building Construction Thermal Isolation Materials (Rockwool)

    OpenAIRE

    M. Itewi

    2011-01-01

    Problem statement: Building insulation consisting roughly to anything in a structure that is utilizes as insulation for any reason. Thermal insulation in structures is a significant feature to attaining thermal comfort for its tenants. Approach: Insulation decreases unnecessary warmth loss or gain and can reduce the power burdens of heating and cooling structures. It does not automatically having anything to do with problems of sufficient exposure to air and might or might...

  5. Thermal Models for Intelligent Heating of Buildings

    DEFF Research Database (Denmark)

    Thavlov, Anders; Bindner, Henrik W.

    2012-01-01

    the comfort of residents, proper prediction models for indoor temperature have to be developed. This paper presents a model for prediction of indoor temperature and power consumption from electrical space heating in an office building, using stochastic differential equations. The heat dynamic model is build......The Danish government has set the ambitious goal that the share of the total Danish electricity consumption, covered by wind energy, should be increased to 50% by year 2020. This asks for radical changes in how we utilize and transmit electricity in the future power grid. To fully utilize the high...... being pursued is to use the heat capacity of the thermal mass in buildings to temporarily store excess power production by increasing the electrical heating. Likewise can the electrical heating be postponed in periods with lack of production. To exploit the potential in thermal storage and to ensure...

  6. Model calibration for building energy efficiency simulation

    International Nuclear Information System (INIS)

    Highlights: • Developing a 3D model relating to building architecture, occupancy and HVAC operation. • Two calibration stages developed, final model providing accurate results. • Using an onsite weather station for generating the weather data file in EnergyPlus. • Predicting thermal behaviour of underfloor heating, heat pump and natural ventilation. • Monthly energy saving opportunities related to heat pump of 20–27% was identified. - Abstract: This research work deals with an Environmental Research Institute (ERI) building where an underfloor heating system and natural ventilation are the main systems used to maintain comfort condition throughout 80% of the building areas. Firstly, this work involved developing a 3D model relating to building architecture, occupancy and HVAC operation. Secondly, the calibration methodology, which consists of two levels, was then applied in order to insure accuracy and reduce the likelihood of errors. To further improve the accuracy of calibration a historical weather data file related to year 2011, was created from the on-site local weather station of ERI building. After applying the second level of calibration process, the values of Mean bias Error (MBE) and Cumulative Variation of Root Mean Squared Error (CV(RMSE)) on hourly based analysis for heat pump electricity consumption varied within the following ranges: (MBE)hourly from −5.6% to 7.5% and CV(RMSE)hourly from 7.3% to 25.1%. Finally, the building was simulated with EnergyPlus to identify further possibilities of energy savings supplied by a water to water heat pump to underfloor heating system. It found that electricity consumption savings from the heat pump can vary between 20% and 27% on monthly bases

  7. Smart Building: Decision Making Architecture for Thermal Energy Management.

    Science.gov (United States)

    Uribe, Oscar Hernández; Martin, Juan Pablo San; Garcia-Alegre, María C; Santos, Matilde; Guinea, Domingo

    2015-10-30

    Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction.

  8. Smart Building: Decision Making Architecture for Thermal Energy Management

    Directory of Open Access Journals (Sweden)

    Oscar Hernández Uribe

    2015-10-01

    Full Text Available Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction.

  9. Smart Building: Decision Making Architecture for Thermal Energy Management

    Science.gov (United States)

    Hernández Uribe, Oscar; San Martin, Juan Pablo; Garcia-Alegre, María C.; Santos, Matilde; Guinea, Domingo

    2015-01-01

    Smart applications of the Internet of Things are improving the performance of buildings, reducing energy demand. Local and smart networks, soft computing methodologies, machine intelligence algorithms and pervasive sensors are some of the basics of energy optimization strategies developed for the benefit of environmental sustainability and user comfort. This work presents a distributed sensor-processor-communication decision-making architecture to improve the acquisition, storage and transfer of thermal energy in buildings. The developed system is implemented in a near Zero-Energy Building (nZEB) prototype equipped with a built-in thermal solar collector, where optical properties are analysed; a low enthalpy geothermal accumulation system, segmented in different temperature zones; and an envelope that includes a dynamic thermal barrier. An intelligent control of this dynamic thermal barrier is applied to reduce the thermal energy demand (heating and cooling) caused by daily and seasonal weather variations. Simulations and experimental results are presented to highlight the nZEB thermal energy reduction. PMID:26528978

  10. Thermal mass impact on energy performance of a low, medium and heavy mass building in Belgrade

    Directory of Open Access Journals (Sweden)

    Anđelković Bojan V.

    2012-01-01

    Full Text Available Heavy mass materials used in building structures and architecture can significantly affect building energy performance and occupant comfort. The purpose of this study was to investigate if thermal mass can improve the internal environment of a building, resulting in lower energy requirements from the mechanical systems. The study was focused on passive building energy performance and compared annual space heating and cooling energy requirements for an office building in Belgrade with several different applications of thermal mass. A three-dimensional building model was generated to represent a typical office building. Building shape, orientation, glazing to wall ratio, envelope insulation thickness, and indoor design conditions were held constant while location and thickness of building mass (concrete was varied between cases in a series of energy simulations. The results were compared and discussed in terms of the building space heating and cooling energy and demand affected by thermal mass. The simulation results indicated that with addition of thermal mass to the building envelope and structure: 100% of all simulated cases experienced reduced annual space heating energy requirements, 67% of all simulated cases experienced reduced annual space cooling energy requirements, 83% of all simulated cases experienced reduced peak space heating demand and 50% of all simulated cases experienced reduced peak space cooling demand. The study demonstrated that there exists a potential for reducing space heating and cooling energy requirements with heavy mass construction in the analyzed climate region (Belgrade, Serbia.

  11. Validation of daylighting model in CODYRUN building simulation code

    OpenAIRE

    Boyer, Harry; Boyer, H.; Guichard, Stéphane; Guichard, S; Jean, Aurélien; Jean, A.; Libelle, Teddy; Libelle, T; Bigot, Dimitri; Miranville, F; Miranville, Frédéric; Bojić, M.

    2015-01-01

    International audience CODYRUN is a multi-zone software integrating thermal building simulation, airflow, and pollutant transfer. A first question thus arose as to the integration of indoor lighting conditions into the simulation, leading to a new model calculating natural and artificial lighting. The results of this new daylighting module were then compared with results of other simulation codes and experimental cases both in artificial and natural environments. Excellent agreements were ...

  12. First Swiss building and urban simulation conference. Conference proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Zweifel, G.; Citherlet, S.; Afjei, T.; Pahud, D.; Robinson, D.; Schaelin, A.

    2010-07-01

    These contributions presented at a conference, held in 2009 in Horw, near Lucerne, Switzerland, deal with the simulation of building technical services. Three contribution blocks dealt with thermal and heating, ventilation and air-conditioning (HVAC) simulation, airflow and stochastic modelling and urban simulation. In the thermal and HVAC simulation session, the potential and limitations of building energy performance simulation is examined from an engineering perspective, a parametric study of an air heat exchanger for the cooling of buildings is presented and a comparison of measured and estimated electric energy use and the impact of assumed occupancy patterns is made. Contributions on standard solutions for energy efficient heating and cooling with heat pumps, the validation and certification of dynamic building simulation tools, standards and tools for the energy performance of buildings with a simple chiller model and the system-simulation of a central solar heating plant with seasonal duct storage in Geneva, Switzerland, are presented. In the airflow and stochastic modelling session, the optimisation of air flow in operating theatres is examined, and air-flow phenomena in flats are explained with illustrations of computational fluid dynamics (CFD). Also, the comparison of test reference years to stochastically generated time series and a comprehensive stochastic model of window usage are discussed. Contributions on the simulation of air-flow patterns and wind loads on facades and the choice of appropriate simulation techniques for the thermal analysis of double skin facades complete the session. In the final Urban Simulation session, a new CFD approach for urban flow and pollution dispersion simulation is presented, a comprehensive micro-simulation of resource flows for sustainable urban planning, multi-scale modelling of the urban climate and the optimisation of urban energy demands using an evolutionary algorithm are discussed.

  13. Rational use of energy by thermal insulation of residential buildings. Rationelle Energienutzung durch Waermeschutz von Wohngebaeuden

    Energy Technology Data Exchange (ETDEWEB)

    Feist, W. (Inst. Wohnen und Umwelt, Darmstadt (Germany))

    1992-01-01

    Processes in buildings need to be studied in detail to determine the technical potential of energy savings. Simulation models for thermal behaviour and simulation calculations prove that the technologies available today and the building input justifiable for the central-European climate will allow so-called passive-systems buildings to be built. Such a passive-systems building was built in Darmstadt Kranichstein. The heart of these passive-systems buildings is an excellent thermal insulation, its meticulous execution and the reduction of heat losses by ventilation. (BWI)

  14. Implementation of Models for Building Envelope Air Flow Fields in a Whole Building Hygrothermal Simulation Tool

    DEFF Research Database (Denmark)

    Rode, Carsten; Grau, Karl

    2009-01-01

    Simulation tools are becoming available which predict the heat and moisture conditions in the indoor environment as well as in the envelope of buildings, and thus it has become possible to consider the important interaction between the different components of buildings and the different physical...... phenomena which occur. However, there is still room for further development of such tools. This paper will present an attempt to integrate modelling of air flows in building envelopes into a whole building hygrothermal simulation tool. Two kinds of air flows have been considered: 1. Air flow in ventilated...... cavity such as in the exterior cladding of building envelopes, i.e. a flow which is parallel to the construction plane. 2. Infiltration/exfiltration of air through the building envelope, i.e. a flow which is perpendicular to the construction plane. The new models make it possible to predict the thermal...

  15. Using Expert Systems To Build Cognitive Simulations.

    Science.gov (United States)

    Jonassen, David H.; Wang, Sherwood

    2003-01-01

    Cognitive simulations are runnable computer programs for modeling human cognitive activities. A case study is reported where expert systems were used as a formalism for modeling metacognitive processes in a seminar. Building cognitive simulations engages intensive introspection, ownership and meaning making in learners who build them. (Author/AEF)

  16. Calibration process and energy simulation of a building

    OpenAIRE

    Gerphagnon, Solène

    2016-01-01

    In the current context of ongoing search for improvement of energy performance, the management of buildings’ energy performance has become a very important stake. Openergy aims to revolutionize the energy monitoring of buildings thanks to dynamic thermal simulation. The calibration of the simulation consists in adjusting different input parameters in order to have results close to reality. This convergence is generally guided by an expert of the field, but it aims to become automatic, in orde...

  17. Thermal analysis and design of passive solar buildings

    CERN Document Server

    Athienitis, AK

    2013-01-01

    Passive solar design techniques are becoming increasingly important in building design. This design reference book takes the building engineer or physicist step-by-step through the thermal analysis and design of passive solar buildings. In particular it emphasises two important topics: the maximum utilization of available solar energy and thermal storage, and the sizing of an appropriate auxiliary heating/cooling system in conjunction with good thermal control.Thermal Analysis and Design of Passive Solar Buildings is an important contribution towards the optimization of buildings as systems th

  18. Twenty Years On!: Updating the IEA BESTEST Building Thermal Fabric Test Cases for ASHRAE Standard 140

    Energy Technology Data Exchange (ETDEWEB)

    Judkoff, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Neymark, J. [J. Neymark & Associates, Golden, CO (United States)

    2013-07-01

    ANSI/ASHRAE Standard 140, Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs applies the IEA BESTEST building thermal fabric test cases and example simulation results originally published in 1995. These software accuracy test cases and their example simulation results, which comprise the first test suite adapted for the initial 2001 version of Standard 140, are approaching their 20th anniversary. In response to the evolution of the state of the art in building thermal fabric modeling since the test cases and example simulation results were developed, work is commencing to update the normative test specification and the informative example results.

  19. Coupling of Thermal Mass with Night Ventilation in Buildings

    Science.gov (United States)

    Endurthy, Akhilesh Reddy

    Passive cooling designs & technologies offer great promise to lower energy use in buildings. Though the working principles of these designs and technologies are well understood, simplified tools to quantitatively evaluate their performance are lacking. Cooling by night ventilation, which is the topic of this research, is one of the well known passive cooling technologies. The building's thermal mass can be cooled at night by ventilating the inside of the space with the relatively lower outdoor air temperatures, thereby maintaining lower indoor temperatures during the warmer daytime period. Numerous studies, both experimental and theoretical, have been performed and have shown the effectiveness of the method to significantly reduce air conditioning loads or improve comfort levels in those climates where the night time ambient air temperature drops below that of the indoor air. The impact of widespread adoption of night ventilation cooling can be substantial, given the large fraction of energy consumed by air conditioning of buildings (about 12-13% of the total electricity use in U.S. buildings). Night ventilation is relatively easy to implement with minimal design changes to existing buildings. Contemporary mathematical models to evaluate the performance of night ventilation are embedded in detailed whole building simulation tools which require a certain amount of expertise and is a time consuming approach.

  20. The thermal performance of earth buildings

    Directory of Open Access Journals (Sweden)

    Heathcote, K.

    2011-09-01

    Full Text Available This paper examines the theoretical basis for the thermal performance of earth walls and links it to some test results on buildings constructed by the author, and to their predicted performance using a sophisticated computer modelling program. The analysis shows that for all earth walls the steady state thermal resistance is low but that for walls greater than about 450 mm thick the cyclic thermal resistance is high and increases exponentially. Whilst the steady state resistance of all thickness walls is low and results in higher than normal average temperatures in summer and lower than normal in winter the ability of thick earth walls to even out the swings in temperature is thought to be responsible for the materials reputation. The paper notes that good passive design principles (such as providing internal thermal mass and large areas of glazing for winter performance will greatly improve the performance of earth buildings with thin walls, but it is the author’s opinion that external earth walls should be at least 450 mm thick to gain the full benefit of thermal mass.

    Este artículo examina la base teórica del comportamiento térmico de las paredes de tierra y la relaciona con varios resultados de test realizados sobre edificios construidos por el autor, y con su comportamiento previsto utilizando un sofisticado programa de modelado por ordenador. El análisis muestra que la resistencia térmica constante es baja para todas las paredes de tierra, pero que para muros con un grosor mayor que 450 mm la resistencia térmica cíclica es alta y se incrementa exponencialmente. Mientras que la resistencia térmica constante de las paredes de cualquier grosor es baja y se traduce en temperaturas más altas que la media en verano y más bajas que la media en invierno, la capacidad de las paredes gruesas de tierra para amortiguar las variaciones de temperatura es la responsable de la reputación de los materiales. El artículo señala que los

  1. The impact of indoor thermal conditions, system controls and building types on the building energy demand

    Energy Technology Data Exchange (ETDEWEB)

    Corgnati, Stefano Paolo; Fabrizio, Enrico; Filippi, Marco [Dipartimento di Energetica (DENER), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2008-07-01

    It is possible to evaluate the energy demand as well as the parameters related to indoor thermal comfort through building energy simulation tools. Since energy demand for heating and cooling is directly affected by the required level of thermal comfort, the investigation of the mutual relationship between thermal comfort and energy demand (and therefore operating costs) is of the foremost importance both to define the benchmarks for energy service contracts and to calibrate the energy labelling according to European Directive 2002/92/CE. The connection between indoor thermal comfort conditions and energy demand for both heating and cooling has been analyzed in this work with reference to a set of validation tests (office buildings) derived from a European draft standard. Once a range of required acceptable indoor operative temperatures had been fixed in accordance with Fanger's theory (e.g. -0.5 < PMV < -0.5), the effective hourly comfort conditions and the energy consumptions were estimated through dynamic simulations. The same approach was then used to quantify the energy demand when the range of acceptable indoor operative temperatures was fixed in accordance with de Dear's adaptive comfort theory. (author)

  2. Dynamic simulation of a high efficiency building

    OpenAIRE

    Dot Bardolet, Núria

    2009-01-01

    The dynamic simulation of the heat transfer between buildings and their environment is situdied through the software TRNSYS. First, a very simple building is considered and the energy demand for heating evaluated through TRNSYS is compared with that obtained by apllying the Italian Standard UNI TS 11300-1:2008. This excersise has the purpose of verifying the correct use of the simulation program. Then, the annual energy demand for heating, cooling and humidity control, with reference to a wel...

  3. Empirical Validation of Building Simulation Software

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Heiselberg, Per

    The work described in this report is the result of a collaborative effort of members of the International Energy Agency (IEA), Task 34/43: Testing and validation of building energy simulation tools experts group.......The work described in this report is the result of a collaborative effort of members of the International Energy Agency (IEA), Task 34/43: Testing and validation of building energy simulation tools experts group....

  4. Collapse simulation of building constructions

    Directory of Open Access Journals (Sweden)

    Nekrest'yanov Viktor Nikolaevich

    Full Text Available The physical reasons for building structures destruction are both the forces arising at stress-strain state of construction elements and external influences arising at emergency situations, as well as their moments, impulses and periodic impulses with the frequencies close to of fluctuations frequencies of construction elements. We shall call the mathematical calculation models for the parameters-reasons of destructions the basic models. The basic models of destruction of building structures elements allow not only providing necessary level of reliability and survivability of the elements and the construction as a whole already at the stage of their design, but also giving the chance, at their corresponding completion, to provide rational decisions on the general need of recovery works and their volume depending on destruction level. Especially important for rational design decisions development, which ensure the demanded constructional safety of building structures, is library creation of the basic mathematical models of standard processes of bearing elements destructions for standard construction designs for the purpose of the further forecast (assessment of the level and probabilities of standard destructions. Some basic mathematical models of destructions processes of the standard elements of building structures are presented in the present article. A model of accounting for construction defects and a model of obtaining requirements to probabilities of partial destructions of a construction are given. Both of these models are probabilistic.

  5. Comparison of Buildings\\' Thermal Loads against Building Orientations for Sustainable Housing in Pakistan

    Directory of Open Access Journals (Sweden)

    Arif Khan

    2012-07-01

    Full Text Available As the sustainable settlements have been included as a vital end product of all planning exercises, the architectural layouts should be well integrated with the sun path charts and the orientations of windows. Appropriate orientations can offer thermally indoor conditions besides physical and psychological comfort in any settlement at lesser energy demand. This investigation uses a vast number of computer simulations to visualize and make better decisions about heating and cooling requirements of a building and facades as a function of window orientation in composite climatic condition of Lahore. This study in particular evaluates the solar load in residential buildings responsive to the objective of sustainable new housing leading to thoughtful integration of architecture. The orientation of the buildings could then be essentially integrated to the current architectural and urban design practices in order to optimize the relationship between the given site ant the orientations for sustainable developments.

  6. Thermally activated building systems in context of increasing building energy efficiency

    OpenAIRE

    Stojanović Branislav V.; Janevski Jelena N.; Mitković Petar B.; Stojanović Milica B.; Ignjatović Marko G.

    2014-01-01

    One of the possible ways to provide heating to the building is to use thermally activated building systems. This type of heating, besides providing significant increase in building energy efficiency, allows using low-temperature heating sources. In this paper, special attention is given to opaque part of the building façade with integrated thermally activated building systems. Due to fact that this type of system strongly depends on temperature of this cons...

  7. Impact of UK Building Regulations on design and thermal performance of dwellings

    Institute of Scientific and Technical Information of China (English)

    LIM; D; 姚润明

    2009-01-01

    This paper looks at the progressive impact of UK Building Regulations (Part L) on the energy consumption of dwellings with respect to thermal performance of the building envelope. It provides an overview of building legislation,highlighting progressive improvement in building elemental U-values and compliance methods. The focus centres on Building Regulations from 1965 to 2006,at a time when energy conservation has become an integral component of building control due to environmental concerns. Simulation software is used to compare energy consumption for 5 typical UK dwelling types through a series of case studies which illustrate the rate of impact over recent years.

  8. Green Building Construction Thermal Isolation Materials (Rockwool

    Directory of Open Access Journals (Sweden)

    M. Itewi

    2011-01-01

    Full Text Available Problem statement: Building insulation consisting roughly to anything in a structure that is utilizes as insulation for any reason. Thermal insulation in structures is a significant feature to attaining thermal comfort for its tenants. Approach: Insulation decreases unnecessary warmth loss or gain and can reduce the power burdens of heating and cooling structures. It does not automatically having anything to do with problems of sufficient exposure to air and might or might not influence the amount of sound insulation. Results: In a constricted way insulation can just mean the insulation substance used to reduce heat loss, such as: Glass wool, cellulose, polystyrene, rock wool, urethane foam, vermiculite and the earth, but it can also entail a variety of plans and methods used to deal with the chief forms of heat movement like transmission, emission and convection substances. The efficiency of insulation is normally assessed by its R-value. However, an R-value does not allow for the superiority of assembly or narrow green issues for each structure. Building superiority matters comprise insufficient vapor obstructions and troubles with draft-proofing. Additionally, the property and concentration of the insulation substance itself is vital. Fiberglass insulation materials, for example, made out of short fibers of glass covered on top of each other is not as long-lasting as insulation prepared from extended entwined fibers of glass. Conclusion/Recommendations: Rockwool insulation is a kind of insulation that is constructed out of real rocks and minerals. It furthermore is known by the names of mineral wool insulation, stone wool insulation or slag wool insulation. A broad collection of goods can be constructed from Rockwool, because of its outstanding capability to obstruct sound and heat. Rockwool insulation is normally utilized in building assembly, manufacturing plants and in automotive purposes. In this study i proposed to use

  9. Indoor Environment and Energy Use in Historic Buildings - Comparing Survey Results with Measurements and Simulations

    DEFF Research Database (Denmark)

    Rohdin, P.; Dalewski, M.; Moshfegh, B.

    2012-01-01

    Increasing demand for energy efficiency places new requirements on energy use in historic buildings. Efficient energy use is essential if a historic building is to be used and preserved, especially buildings with conventional uses such as residential buildings and offices. This paper presents...... results which combine energy auditing with building energy simulation and an indoor environment survey among the occupants of the building. Both when comparing simulations with measurements as well as with survey results good agreement was found. The two efficiency measures that are predicted to increase...... energy and thermal performance the most for this group of buildings were reduced infiltration and increasing heat-exchanger efficiency....

  10. Radiation exchange between persons and surfaces for building energy simulations

    DEFF Research Database (Denmark)

    Vorre, Mette Havgaard; Jensen, Rasmus Lund; Dreau, Jerome Le

    2015-01-01

    Thermal radiation within buildings is a significant component of thermal comfort. Typically the methods applied for calculating view factors between a person and its building surfaces requires great computational time. This research developed a view factor calculation method suitable for building...... energy simulations. The method calculates view factors by numerical integration of projected area factor. Over time the projected area factor of a person has been simplified by geometrical shapes. These shapes were compared with more complex equations on precision and calculation time. The same was done...... for the resulting view factors, where the results were compared with view factors found by ray tracing. While geometrical simplifications of the human body gave the fastest calculations, the complex equations gave the most accurate results. Non-rectangular surfaces and obstacles were treated by comparing...

  11. Scenario Analysis of Peak Demand Savings for Commercial Buildings with Thermal Mass in California

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Rongxin; Kiliccote, Sila; Piette, Mary Ann; Parrish, Kristen

    2010-05-14

    This paper reports on the potential impact of demand response (DR) strategies in commercial buildings in California based on the Demand Response Quick Assessment Tool (DRQAT), which uses EnergyPlus simulation prototypes for office and retail buildings. The study describes the potential impact of building size, thermal mass, climate, and DR strategies on demand savings in commercial buildings. Sensitivity analyses are performed to evaluate how these factors influence the demand shift and shed during the peak period. The whole-building peak demand of a commercial building with high thermal mass in a hot climate zone can be reduced by 30percent using an optimized demand response strategy. Results are summarized for various simulation scenarios designed to help owners and managers understand the potential savings for demand response deployment. Simulated demand savings under various scenarios were compared to field-measured data in numerous climate zones, allowing calibration of the prototype models. The simulation results are compared to the peak demand data from the Commercial End-Use Survey for commercial buildings in California. On the economic side, a set of electricity rates are used to evaluate the impact of the DR strategies on economic savings for different thermal mass and climate conditions. Our comparison of recent simulation to field test results provides an understanding of the DR potential in commercial buildings.

  12. Comparative Validation of Building Simulation Software

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Heiselberg, Per

    _2 and DSF200_4, the third empirical test case is also specified as DSF400_3, but it's completion is under consideration. The comparative test cases can not be directly used for the validation of the software due to often disagreement of the results, however the result of the exercises...... is that the comparative validation can be regarded as the main argument to continue the validation of the building simulation software for the buildings with the double skin façade with the empirical validation test cases.......The scope of this subtask is to perform a comparative validation of the building simulation software for the buildings with the double skin façade. The outline of the results in the comparative validation identifies the areas where is no correspondence achieved, i.e. calculation of the air flow...

  13. Integrated thermal modelling of photovoltaic panels for the solar protection of buildings in tropical and humid conditions

    OpenAIRE

    Miranville, Frédéric; Bigot, Dimitri; Boyer, Harry

    2008-01-01

    This paper deals with the integrated thermal modelling of photovoltaic panels for the solar protection of buildings under strong solar radiation as encountered in tropical and humid conditions. The thermal model is integrated in a building simulation code and is able to predict the thermal impact of PV panels installed on buildings in several configurations and also their electric production. Basically, the PV panel is considered as a complex wall within which coupled heat transfer occur. Con...

  14. Solar passive building in Delhi: numerical simulation and validation

    Energy Technology Data Exchange (ETDEWEB)

    Sodha, M.S.; Garg, S.N.; Sawhney, R.L.; Chandra, R.; Bansal, N.K.; Sharma, A.K.; Gupta, V.K.

    A two floor hostel for married research scholars consisting of 12 apartments was designed and constructed for the composite climate of Delhi; the design incorporates many passive features. Using a modified admittance procedure and Fourier analysis of the periodic parameters, the building was numerically simulated to obtain its thermal performance on an hourly basis. Two apartments of the building (one on the ground floor and one of the first floor) have been experimentally monitored by a microprocessor aided data acquisition system. The observations validate the numerical model. (author).

  15. Building America House Simulation Protocols (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    Hendron, R.; Engebrecht, C.

    2010-10-01

    The House Simulation Protocol document was developed to track and manage progress toward Building America's multi-year, average whole-building energy reduction research goals for new construction and existing homes, using a consistent analytical reference point. This report summarizes the guidelines for developing and reporting these analytical results in a consistent and meaningful manner for all home energy uses using standard operating conditions.

  16. Thermal diffusivity of simulated DUPIC fuel

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kweon Ho; Yang, M. S.; Bae, K. K.; Moon, I. H.; Jung, K. C.; Song, H. S.; Park, C. Y.; Lee, D. J.; Kim, H. S

    2000-06-01

    Thermal diffusivity of simulated DUPIC fuel was measured using Laser Flash Method in the temperautre range from room temperature to 1350 deg C. Density of simulated DUPIC fuel used in the measurement of thermal difusivity was 10.16 g/cm{sup 3} (94.2% of theoretical density) at room temperature and diameter and thickness were 10 mm and 1 mm, respectively. Thermal diffusivity decreased from 0.01857 cm{sup 2}/s at room temperature to 0.00523 cm{sup 2}/s at 1350 deg C. Thermal diffusivity of simulated DUPIC fuel and UO{sub 2} and simulated spent fuel. The difference of thermal diffusivity between simulated DUPIC fule and UO{sub 2} and simulated spent fuel was high and it decreased due to temperature increase.

  17. Thermal comfort in residential buildings by the millions

    DEFF Research Database (Denmark)

    Østergård, Torben; Jensen, Rasmus Lund; Maagaard, Steffen

    2016-01-01

    In Danish building code and many design briefings, criteria regarding thermal comfort are defined for “critical” rooms in residential buildings. Identifying the critical room is both difficult and time-consuming for large, multistory buildings. To reduce costs and time, such requirement often cau...

  18. Analysis of volatile organic compounds released from the decay of surrogate human models simulating victims of collapsed buildings by thermal desorption-comprehensive two-dimensional gas chromatography-time of flight mass spectrometry.

    Science.gov (United States)

    Agapiou, A; Zorba, E; Mikedi, K; McGregor, L; Spiliopoulou, C; Statheropoulos, M

    2015-07-01

    Field experiments were devised to mimic the entrapment conditions under the rubble of collapsed buildings aiming to investigate the evolution of volatile organic compounds (VOCs) during the early dead body decomposition stage. Three pig carcasses were placed inside concrete tunnels of a search and rescue (SAR) operational field terrain for simulating the entrapment environment after a building collapse. The experimental campaign employed both laboratory and on-site analytical methods running in parallel. The current work focuses only on the results of the laboratory method using thermal desorption coupled to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (TD-GC×GC-TOF MS). The flow-modulated TD-GC×GC-TOF MS provided enhanced separation of the VOC profile and served as a reference method for the evaluation of the on-site analytical methods in the current experimental campaign. Bespoke software was used to deconvolve the VOC profile to extract as much information as possible into peak lists. In total, 288 unique VOCs were identified (i.e., not found in blank samples). The majority were aliphatics (172), aromatics (25) and nitrogen compounds (19), followed by ketones (17), esters (13), alcohols (12), aldehydes (11), sulfur (9), miscellaneous (8) and acid compounds (2). The TD-GC×GC-TOF MS proved to be a sensitive and powerful system for resolving the chemical puzzle of above-ground "scent of death".

  19. Modelling and simulation of thermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Eborn, J.

    1998-02-01

    Mathematical modelling and simulation are important tools when dealing with engineering systems that today are becoming increasingly more complex. Integrated production and recycling of materials are trends that give rise to heterogenous systems, which are difficult to handle within one area of expertise. Model libraries are an excellent way to package engineering knowledge of systems and units to be reused by those who are not experts in modelling. Many commercial packages provide good model libraries, but they are usually domain-specific and closed. Heterogenous, multi-domain systems requires open model libraries written in general purpose modelling languages. This thesis describes a model database for thermal power plants written in the object-oriented modelling language OMOLA. The models are based on first principles. Subunits describe volumes with pressure and enthalpy dynamics and flows of heat or different media. The subunits are used to build basic units such as pumps, valves and heat exchangers which can be used to build system models. Several applications are described; a heat recovery steam generator, equipment for juice blending, steam generation in a sulphuric acid plant and a condensing steam plate heat exchanger. Model libraries for industrial use must be validated against measured data. The thesis describes how parameter estimation methods can be used for model validation. Results from a case-study on parameter optimization of a non-linear drum boiler model show how the technique can be used 32 refs, 21 figs

  20. A methodological study of environmental simulation in architecture and engineering. Integrating daylight and thermal performance across the urban and building scales

    DEFF Research Database (Denmark)

    Sattrup, Peter Andreas; Strømann-Andersen, Jakob Bjørn

    2011-01-01

    This study presents a methodological and conceptual framework that allows for the integration and creation of knowledge across professional borders in the field of environmental simulation. The framework has been developed on the basis of interviews with leading international practitioners, key t...

  1. Building energy analysis of Electrical Engineering Building from DesignBuilder tool: calibration and simulations

    Science.gov (United States)

    Cárdenas, J.; Osma, G.; Caicedo, C.; Torres, A.; Sánchez, S.; Ordóñez, G.

    2016-07-01

    This research shows the energy analysis of the Electrical Engineering Building, located on campus of the Industrial University of Santander in Bucaramanga - Colombia. This building is a green pilot for analysing energy saving strategies such as solar pipes, green roof, daylighting, and automation, among others. Energy analysis was performed by means of DesignBuilder software from virtual model of the building. Several variables were analysed such as air temperature, relative humidity, air velocity, daylighting, and energy consumption. According to two criteria, thermal load and energy consumption, critical areas were defined. The calibration and validation process of the virtual model was done obtaining error below 5% in comparison with measured values. The simulations show that the average indoor temperature in the critical areas of the building was 27°C, whilst relative humidity reached values near to 70% per year. The most critical discomfort conditions were found in the area of the greatest concentration of people, which has an average annual temperature of 30°C. Solar pipes can increase 33% daylight levels into the areas located on the upper floors of the building. In the case of the green roofs, the simulated results show that these reduces of nearly 31% of the internal heat gains through the roof, as well as a decrease in energy consumption related to air conditioning of 5% for some areas on the fourth and fifth floor. The estimated energy consumption of the building was 69 283 kWh per year.

  2. Energy simulation and optimization for a small commercial building through Modelica

    Science.gov (United States)

    Rivas, Bryan

    Small commercial buildings make up the majority of buildings in the United States. Energy consumed by these buildings is expected to drastically increase in the next few decades, with a large percentage of the energy consumed attributed to cooling systems. This work presents the simulation and optimization of a thermostat schedule to minimize energy consumption in a small commercial building test bed during the cooling season. The simulation occurs through the use of the multi-engineering domain Dymola environment based on the Modelica open source programming language and is optimized with the Java based optimization program GenOpt. The simulation uses both physically based modeling utilizing heat transfer principles for the building and regression analysis for energy consumption. GenOpt is dynamically coupled to Dymola through various interface files. There are very few studies that have coupled GenOpt to a building simulation program and even fewer studies have used Dymola for building simulation as extensively as the work presented here. The work presented proves Dymola as a viable alternative to other building simulation programs such as EnergyPlus and MatLab. The model developed is used to simulate the energy consumption of a test bed, a commissioned real world small commercial building, while maintaining indoor thermal comfort. Potential applications include smart or intelligent building systems, predictive simulation of small commercial buildings, and building diagnostics.

  3. 2014 Building America House Simulation Protocols

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, E. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Engebrecht, C. Metzger [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Horowitz, S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hendron, R. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2014-03-01

    As Building America has grown to include a large and diverse cross-section of the home building and retrofit industries, it has become more important to develop accurate, consistent analysis techniques to measure progress towards the program's goals. The House Simulation Protocol (HSP) document provides guidance to program partners and managers so they can compare energy savings for new construction and retrofit projects. The HSP provides the program with analysis methods that are proven to be effective and reliable in investigating the energy use of advanced energy systems and of entire houses.

  4. Thermal and acoustic environmental requirements for green buildings in Malaysia

    Directory of Open Access Journals (Sweden)

    Sreenivasaiah Purushothama Rao

    2012-12-01

    Full Text Available Passive design concepts as a strategy for achieving energy efficiency as well as optimum indoor thermal comfort in workspaces are being increasingly applied with the increased awareness of Green Buildings. The challenging task for the building designers in the hot-humid tropics is the provision of indoor thermal comfort for the occupants of the building while reducing energy consumption in the office spaces. Acoustic quality is also an important element in ensuring a healthy working environment. One of the aims of a green building is to minimise its impact on health and performance of the occupants of the building. This has been emphasized in most green building rating systems under requirements for Indoor Environmental Quality (IEQ, highlighting the four main points for achieving an improved indoor environment, viz., indoor air quality, acoustics, visual comfort (lighting and thermal comfort. Although acoustics was mentioned in the IEQ criteria, according to previous surveys and studies acoustic quality in green buildings are not improving. Acoustics performance is bound to be relegated unless it is considered early in design stage. This paper makes an attempt at how green building design strategies contribute to the degradation of acoustical environment in green office buildings. The design strategies implemented to cater for green building requirements such as provision of natural ventilation, daylight, reduction of finishes and office layout leads to an unintended decrease in the acoustical quality. This needs to be addressed and corrected by the building professionals.

  5. Advanced Thermal Simulator Testing: Thermal Analysis and Test Results

    Science.gov (United States)

    Bragg-Sitton, Shannon M.; Dickens, Ricky; Dixon, David; Reid, Robert; Adams, Mike; Davis, Joe

    2008-01-01

    Work at the NASA Marshall Space Flight Center seeks to develop high fidelity, electrically heated thermal simulators that represent fuel elements in a nuclear reactor design to support non-nuclear testing applicable to the development of a space nuclear power or propulsion system. Comparison between the fuel pins and thermal simulators is made at the outer fuel clad surface, which corresponds to the outer sheath surface in the thermal simulator. The thermal simulators that are currently being tested correspond to a SNAP derivative reactor design that could be applied for Lunar surface power. These simulators are designed to meet the geometric and power requirements of a proposed surface power reactor design, accommodate testing of various axial power profiles, and incorporate imbedded instrumentation. This paper reports the results of thermal simulator analysis and testing in a bare element configuration, which does not incorporate active heat removal, and testing in a water-cooled calorimeter designed to mimic the heat removal that would be experienced in a reactor core.

  6. Thermal Comfort in a Naturally-Ventilated Educational Building

    OpenAIRE

    David Mwale Ogoli

    2012-01-01

    A comprehensive study of thermal comfort in a naturally ventilated education building (88,000 ft2) in a Chicago suburb will be conducted with 120 student subjects in 2007. This paper discusses some recent trends in worldwide thermal comfort studies and presents a proposal of research for this building through a series of questionnaire tables. Two research methods used inthermal comfort studies are field studies and laboratory experiments in climate-chambers. The various elements that constitu...

  7. Analysis of Indoor Thermal Performance of Solar Buildings and Simulation Software Development%太阳能建筑室内热工性能分析与模拟软件开发

    Institute of Scientific and Technical Information of China (English)

    敖永安; 车丹; 彭亮; 张茜; 李玉雯

    2013-01-01

    According to the solar building characteristics,we established simulation analysis software suitable for solar building indoor thermal performance; analysed the impact of solar energy applied in the building on indoor temperature and load; and provided reference data for the design of the solar building heating and cooling systems. Based on VB visual programming language, using the method of " ADO data control + SQL statement" and through the ODBC connected with database interface, established the national climate database; databases of different wall types, window types, and radiation floor materials in different regions, etc. The program refers to the outer - wall temperature heat transfer calculation method to calculate the indoor cold (heat) load, and the parametric thought that uses APDL( ANSYS parametric design language) to realize the visualization parametric modeling of floor for heat transfer calculation. Then we got the results: for example, on 1 st January in Shenyang, with only solar energy floor heating in practical building conditions, the standard indoor design temperature, 18℃ ,can not be reached;and the amount of auxiliary heat for the water supply temperature controlled at 40℃ is greater than the amount for that uncontrolled when we use solar energy for heating only. This software could calculate thermal parameters of rooms in different locations.different time and different rooms, so it could be used broadly. It also has opened databases and outputs in graphs and tables, so it is easily understood.%目的 针对太阳能建筑自身的特点,编制适用于太阳能建筑的室内热工性能模拟分析软件,分析太阳能在建筑中应用时对室内温度和负荷的影响,为太阳能建筑冷热源系统的设计提供参考.方法 基于Visual Basic可视化程序设计语言,运用“ADO数据控制项+SQL语句”并通过ODBC同数据库接口相连接的方法建立全国气候数据库、适用于不同区域的墙型窗型和

  8. Methodology for Validating Building Energy Analysis Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Judkoff, R.; Wortman, D.; O' Doherty, B.; Burch, J.

    2008-04-01

    The objective of this report was to develop a validation methodology for building energy analysis simulations, collect high-quality, unambiguous empirical data for validation, and apply the validation methodology to the DOE-2.1, BLAST-2MRT, BLAST-3.0, DEROB-3, DEROB-4, and SUNCAT 2.4 computer programs. This report covers background information, literature survey, validation methodology, comparative studies, analytical verification, empirical validation, comparative evaluation of codes, and conclusions.

  9. Energy consumption in buildings and female thermal demand

    Science.gov (United States)

    Kingma, Boris; van Marken Lichtenbelt, Wouter

    2015-12-01

    Energy consumption of residential buildings and offices adds up to about 30% of total carbon dioxide emissions; and occupant behaviour contributes to 80% of the variation in energy consumption. Indoor climate regulations are based on an empirical thermal comfort model that was developed in the 1960s (ref. ). Standard values for one of its primary variables--metabolic rate--are based on an average male, and may overestimate female metabolic rate by up to 35% (ref. ). This may cause buildings to be intrinsically non-energy-efficient in providing comfort to females. Therefore, we make a case to use actual metabolic rates. Moreover, with a biophysical analysis we illustrate the effect of miscalculating metabolic rate on female thermal demand. The approach is fundamentally different from current empirical thermal comfort models and builds up predictions from the physical and physiological constraints, rather than statistical association to thermal comfort. It provides a substantiation of the thermal comfort standard on the population level and adds flexibility to predict thermal demand of subpopulations and individuals. Ultimately, an accurate representation of thermal demand of all occupants leads to actual energy consumption predictions and real energy savings of buildings that are designed and operated by the buildings services community.

  10. RP{sub P}erformance, a design tool to simulate the thermal performance of high-latitude roof pond buildings (Skytherm North roof ponds); Programa de computo para la simulacion termica de sistemas de techo con estanque para latitudes altas (Skytherm North Roofponds)

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A. G.

    2004-07-01

    This article introduces RP{sub P}erformance, a design tool to simulate the thermal performance of high-latitude roof pond buildings (also known as Skytherm North roof ponds). RP{sub P}erformance is an interactive Microsoft Excel spreadsheet that allows users to modify all the parameters that influence the thermal performance of a Skytherm North roof pond building giving as outputs the heating and cooling costs, as well as a series of indoor temperature charts for a roof pond, a highly-insulated reference building, and a conventionally insulated reference building. This article also presents the calibration study of RP{sub P}erformance using experimental results obtained over a nine-month period in an 11.9 m2 test-room located in Muncie, Indiana. (Author)

  11. Energy flow and thermal comfort in buildings

    DEFF Research Database (Denmark)

    Le Dreau, Jerome

    insulated buildings (R > 5 m2.K/W). In case of single-storey building with a low level of insulation, the effectiveness of radiant terminals is lower due to the larger back losses, and an air-based terminal might be more energy-efficient than a radiant terminal (in terms of delivered energy). Regarding...... is based on both radiation and convection. Radiant terminals have the advantage of making use of low grade sources (i.e. low temperature heating and high temperature cooling), thus decreasing the primary energy consumption of buildings. But there is a lack of knowledge on the heat transfer from...... beam. The higher the air change rate and the warmer the outdoor air, the larger the savings achieved with a radiant cooling terminals. Therefore radiant terminals have a large potential of energy savings for buildings with high ventilation rates (e.g. shop, train station, industrial storage). Among...

  12. Indoor Thermal Environment in Tropical Climate Residential Building

    OpenAIRE

    Jamaludin Nazhatulzalkis; Khamidi Mohd Faris; Abdul Wahab Suriani Ngah; Klufallah Mustafa M. A.

    2014-01-01

    Indoor thermal environment is one of the criteria in sustainable building. This criterion is important in ensuring a healthy indoor environment for the occupants. The consideration of environmental concerns at the early design stage would effectively integrate the sustainability of the building environment. Global climate changes such as global warming do affect human comfort since people spend most of their time and activities in the building. The increasing of urban population required addi...

  13. The effect of simplifying the building description on the numerical modeling of its thermal performance

    Energy Technology Data Exchange (ETDEWEB)

    Stetiu, C.

    1993-07-01

    A thermal building simulation program is a numerical model that calculates the response of the building envelopes to weather and human activity, simulates dynamic heating and cooling loads, and heating and cooling distribution systems, and models building equipment operation. The scope of the research is to supply the users of such programs with information about the dangers and benefits of simplifying the input to their models. The Introduction describes the advantages of modeling the heat transfer mechanisms in a building. The programs that perform this type of modeling have, however, limitations. The user is therefore often put in the situation of simplifying the floor plans of the building under study, but not being able to check the effects that this approximation introduces in the results of the simulation. Chapter 1 is a description of methods. It also introduces the floor plans for the office building under study and the ``reasonable`` floor plans simplifications. Chapter 2 presents DOE-2, the thermal building simulation program used in the sensitivity study. The evaluation of the accuracy of the DOE-2 program itself is also presented. Chapter 3 contains the sensitivity study. The complicated nature of the process of interpreting the temperature profile inside a space leads to the necessity of defining different building modes. The study compares the results from the model of the detailed building description with the results from the models of the same building having simplified floor plans. The conclusion is reached that a study of the effects of simplifying the floor plans of a building is important mainly for defining the cases in which this approximation is acceptable. Different results are obtained for different air conditioning/load regimes of the building. 9 refs., 24 figs.

  14. Simulation of Thermal Comfort of a Residential House

    Directory of Open Access Journals (Sweden)

    Masine Md. Tap

    2011-09-01

    Full Text Available In hot and humid climates thermal comfort can become a problem to the occupants of many residential buildings especially when they are not equipped with air-conditioning system. This paper presents outcomes of an ongoing research work to investigate thermal comfort level in a naturally ventilated residential house in Malaysia using computational fluid dynamics (CFD method. Actual measurements of the temperature distribution, relative humidity and air flow pattern were conducted. CFD simulations on the model of the house allow us to visualize the temperature distribution and air flow pattern and velocity in the house. The thermal comfort in the house was found to be well outside the limits specified by ASHRAE standards. CFD simulation was used to investigate the effects of using a ceiling fan installed in the middle of the hall section and rotating at 150 RPM. It was found that the fan produced swirling flow pattern in the hall section resulting in a more uniform temperature distribution inside the house. However, there is no significant improvement in the thermal comfort level in the house. Results of CFD simulations also show that the use of small extractor fans installed on the front and back walls has no significant effects on the thermal comfort level in the house. Although the mechanical ventilation devices did not help improve the thermal comfort in the house being studied, the CFD simulation results can be used by building designers and engineers to further improved the level of thermal comfort in residential houses in hot and humid climates that are naturally ventilated.

  15. Thermally activated building systems in office buildings: impact of control strategy on energy performance and thermal comfort

    OpenAIRE

    Sourbron, Maarten; Helsen, Lieve

    2010-01-01

    At the Science Park Arenberg site in Leuven (Belgium) two new office buildings equipped with thermally activated building systems (TABS) to cover the cooling load and the base heating load, are constructed. A ground coupled heat pump/direct cooling (HP/DC) system supplies heat and cold to the TABS, while a gas boiler/chiller combination feeds the air handling units. This paper evaluates the impact of the TABS control strategy on both energy consumption and thermal comfort. Furthermore, con...

  16. Simulation Of Probabilistic Wind Loads On A Building

    Science.gov (United States)

    Chamis, Christos C.; Shah, Ashwin R.

    1994-01-01

    Method of simulating probabilistic windloads on building developed. Numerical results of simulation used to assess reliability of building and risk associated with tendencies of large gusts or high steady winds to cause building to sway, buckle, and/or overturn. Using method to analyze proposed design in iterative design cycle, building designed for specified reliability.

  17. Thermal Comfort and Ventilation Criteria for low Energy Residential Buildings in Building Codes

    DEFF Research Database (Denmark)

    Cao, Guangyu; Kurnitski, Jarek; Awbi, Hazim;

    2012-01-01

    Indoor environmental quality and energy performance of buildings are becoming more and more important in the design and construction of low energy, passive and zero energy buildings. At the same time, improved insulation and air tightness have the potential to resulting in a deterioration...... of the indoor air quality in such buildings. Currently, there are no global guidelines for specifying the indoor thermal environment in such low-energy buildings. The objective of this paper is to analyse the classification of indoor thermal comfort levels and recommended ventilation rates for different low...

  18. Thermal Simulation of AC Electromagnetic Contactor

    Institute of Scientific and Technical Information of China (English)

    NIUChun-ping; CHENDe-gui; ZHANGJing-shu; LIXing-wen

    2005-01-01

    Transient magnetic circuit method is adopted to calculate the power loss in winding and shading coil. Based on the analysis of heat transfer process in AC contactor, a thermal model is proposed and the temperature field distribution is simulated with 3-D FEM of ANSYS.Comparison of simulation results with measurements shows that the proposed method is effective.

  19. MCGUIDE: a thermal neutron guide simulation program

    International Nuclear Information System (INIS)

    The computer code MCGUIDE is presented which simulates the transmission of a real (ie imperfect) thermal neutron guide tube. The general form in which the guide is described enables the simulation of combinations of straight and curved sections, gaps, and funnels, together with effects due to mechanical misalignment. (U.K.)

  20. Simulation and evaluation of latent heat thermal energy storage

    Science.gov (United States)

    Sigmon, T. W.

    1980-01-01

    The relative value of thermal energy storage (TES) for heat pump storage (heating and cooling) as a function of storage temperature, mode of storage (hotside or coldside), geographic locations, and utility time of use rate structures were derived. Computer models used to simulate the performance of a number of TES/heat pump configurations are described. The models are based on existing performance data of heat pump components, available building thermal load computational procedures, and generalized TES subsystem design. Life cycle costs computed for each site, configuration, and rate structure are discussed.

  1. Residential photovoltaic system simulation: Thermal aspects

    Science.gov (United States)

    Hart, G. W.; Raghuraman, P.

    1982-04-01

    A TRNSYS simulation was developed to simulate the performance of utility interactive residential photovoltaic energy systems. The PV system is divided into its major functional components, which are individually described with computer models. These models are described in detail. The results of simulation and actual measured data obtained a MIT Lincoln Laboratory's Northeast Residential Station are compared. The thermal influences on the design of such photovoltaic energy systems are given particular attention.

  2. Twenty Years On!: Updating the IEA BESTEST Building Thermal Fabric Test Cases for ASHRAE Standard 140: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Judkoff, R.; Neymark, J.

    2013-07-01

    ANSI/ASHRAE Standard 140, Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs applies the IEA BESTEST building thermal fabric test cases and example simulation results originally published in 1995. These software accuracy test cases and their example simulation results, which comprise the first test suite adapted for the initial 2001 version of Standard 140, are approaching their 20th anniversary. In response to the evolution of the state of the art in building thermal fabric modeling since the test cases and example simulation results were developed, work is commencing to update the normative test specification and the informative example results.

  3. Building a parallel file system simulator

    International Nuclear Information System (INIS)

    Parallel file systems are gaining in popularity in high-end computing centers as well as commercial data centers. High-end computing systems are expected to scale exponentially and to pose new challenges to their storage scalability in terms of cost and power. To address these challenges scientists and file system designers will need a thorough understanding of the design space of parallel file systems. Yet there exist few systematic studies of parallel file system behavior at petabyte- and exabyte scale. An important reason is the significant cost of getting access to large-scale hardware to test parallel file systems. To contribute to this understanding we are building a parallel file system simulator that can simulate parallel file systems at very large scale. Our goal is to simulate petabyte-scale parallel file systems on a small cluster or even a single machine in reasonable time and fidelity. With this simulator, file system experts will be able to tune existing file systems for specific workloads, scientists and file system deployment engineers will be able to better communicate workload requirements, file system designers and researchers will be able to try out design alternatives and innovations at scale, and instructors will be able to study very large-scale parallel file system behavior in the class room. In this paper we describe our approach and provide preliminary results that are encouraging both in terms of fidelity and simulation scalability.

  4. 2014 Building America House Simulation Protocols

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, E.; Engebrecht-Metzger, C.; Horowitz, S.; Hendron, R.

    2014-03-01

    As BA has grown to include a large and diverse cross-section of the home building and retrofit industries, it has become more important to develop accurate, consistent analysis techniques to measure progress towards the program's goals. The House Simulation Protocol (HSP) document provides guidance to program partners and managers so they can compare energy savings for new construction and retrofit projects. The HSP provides the program with analysis methods that are proven to be effective and reliable in investigating the energy use of advanced energy systems and of entire houses.

  5. Automated Translation and Thermal Zoning of Digital Building Models for Energy Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Nathaniel L. [Cornell University; McCrone, Colin J. [Cornell University; Walter, Bruce J. [Cornell University; Pratt, Kevin B. [Cornell University; Greenberg, Donald P. [Cornell University

    2013-08-26

    Building energy simulation is valuable during the early stages of design, when decisions can have the greatest impact on energy performance. However, preparing digital design models for building energy simulation typically requires tedious manual alteration. This paper describes a series of five automated steps to translate geometric data from an unzoned CAD model into a multi-zone building energy model. First, CAD input is interpreted as geometric surfaces with materials. Second, surface pairs defining walls of various thicknesses are identified. Third, normal directions of unpaired surfaces are determined. Fourth, space boundaries are defined. Fifth, optionally, settings from previous simulations are applied, and spaces are aggregated into a smaller number of thermal zones. Building energy models created quickly using this method can offer guidance throughout the design process.

  6. Interaction of a solar space heating system with the thermal behavior of a building

    Energy Technology Data Exchange (ETDEWEB)

    Vilmer, C.; Warren, M.L.; Auslander, D.

    1980-12-01

    The thermal behavior of a building in response to heat input from an active solar space heating system is analyzed to determine the effect of the variable storage tank temperature on the cycling rate, on-time, and off-time of a heating cycle and on the comfort characteristics of room air temperature swing and of offset of the average air temperature from the setpoint (droop). A simple model of a residential building, a fan coil heat-delivery system, and a bimetal thermostat are used to describe the system. A computer simulation of the system behavior has been developed and verified by comparisons with predictions from previous studies. The system model and simulation are then applied to determine the building response to a typical hydronic solar heating system for different solar storage temperatures, outdoor temperatures, and fan coil sizes. The simulations were run only for those cases where there was sufficient energy from storage to meet the building load requirements.

  7. Reservoir Thermal Recover Simulation on Parallel Computers

    Science.gov (United States)

    Li, Baoyan; Ma, Yuanle

    The rapid development of parallel computers has provided a hardware background for massive refine reservoir simulation. However, the lack of parallel reservoir simulation software has blocked the application of parallel computers on reservoir simulation. Although a variety of parallel methods have been studied and applied to black oil, compositional, and chemical model numerical simulations, there has been limited parallel software available for reservoir simulation. Especially, the parallelization study of reservoir thermal recovery simulation has not been fully carried out, because of the complexity of its models and algorithms. The authors make use of the message passing interface (MPI) standard communication library, the domain decomposition method, the block Jacobi iteration algorithm, and the dynamic memory allocation technique to parallelize their serial thermal recovery simulation software NUMSIP, which is being used in petroleum industry in China. The parallel software PNUMSIP was tested on both IBM SP2 and Dawn 1000A distributed-memory parallel computers. The experiment results show that the parallelization of I/O has great effects on the efficiency of parallel software PNUMSIP; the data communication bandwidth is also an important factor, which has an influence on software efficiency. Keywords: domain decomposition method, block Jacobi iteration algorithm, reservoir thermal recovery simulation, distributed-memory parallel computer

  8. Building thermal envelope systems and materials (BTESM) progress report for DOE Office of Buildings Energy Research

    Energy Technology Data Exchange (ETDEWEB)

    Burn, G. (comp.)

    1990-10-01

    The Monthly Report of the Building Thermal Envelope Systems and Materials (BTESM) Program is a monthly update of both in-house ORNL projects and subcontract activities in the research areas of building materials, wall systems, foundations, roofs, and building diagnostics. Presentations are not stand-alone paragraphs every month. Their principal values are the short-time lapse between accomplishment and reporting and their evolution over a period of several months.

  9. Computer simulation of thermal plant operations

    CERN Document Server

    O'Kelly, Peter

    2012-01-01

    This book describes thermal plant simulation, that is, dynamic simulation of plants which produce, exchange and otherwise utilize heat as their working medium. Directed at chemical, mechanical and control engineers involved with operations, control and optimization and operator training, the book gives the mathematical formulation and use of simulation models of the equipment and systems typically found in these industries. The author has adopted a fundamental approach to the subject. The initial chapters provide an overview of simulation concepts and describe a suitable computer environment.

  10. Influence of Building Envelope Thermal Mass on Heating Design Temperature

    Science.gov (United States)

    Gaujena, B.; Borodinecs, A.; Zemitis, J.; Prozuments, A.

    2015-11-01

    The stability of indoor air parameters is a very important factor, essential for such institutions as museums, schools and hospitals. Nowadays the use of renewable energy for space heating became one of the top priorities in modern building design. The active and passive solar energy as well as heat pumps are widely used nowadays. However, such technologies have a limitation in cold climates and often are not able to cover maximal heating loads. This paper is devoted to analysis of influence of building envelope's properties and outdoor air parameters on indoor air thermodynamic parameters stability in winter time. It presents analysis of thermal mass impact on building energy performance and indoor air parameter stability in cold climate. The results show that the thermal mass of building envelope is able to cover extreme winter temperatures as well as in case of emergency heat supply break.

  11. Sensitivity analysis and application guides for integrated building energy and CFD simulation

    Energy Technology Data Exchange (ETDEWEB)

    Zhiqiang John Zhai [Colorado Univ., Boulder, CO (United States). Dept. of Civil, Environmental, and Architectural Engineering; Qingyan Yan Chen [Purdue Univ., West Lafayette, IN (United States). School of Mechanical Engineering

    2006-09-15

    Building energy simulation (ES) and computational fluid dynamics (CFD) programs provide complementary information essential to evaluating building thermal performance. Integration of the two programs eliminates many model assumptions in separate applications and thus improves the quality of simulation results. This paper discusses the potential building and environmental characteristics that may affect the necessity and effectiveness of applying an ES-CFD coupling simulation. These characteristics and the solution accuracy requirement determine whether a coupled simulation is needed for a specific building and which coupling method can provide the best solution with the compromise of both accuracy and efficiency. The study conducts a sensitivity analysis of the coupling simulation to the potential influential factors, based on which general suggestions on appropriate usage of the coupling simulation are provided. (author)

  12. Sensitivity analysis and application guides for integrated building energy and CFD simulation

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Z.J. [Department of Civil, Environmental and Architectural Engineering, University of Colorado at Boulder, Boulder, CO (United States); Chen, Q.Y. [School of Mechanical Engineering, Purdue University, West Lafayette, IN (United States)

    2006-07-01

    Building energy simulation (ES) and computational fluid dynamics (CFD) programs provide complementary information essential to evaluating building thermal performance. Integration of the two programs eliminates many model assumptions in separate applications and thus improves the quality of simulation results. This paper discusses the potential building and environmental characteristics that may affect the necessity and effectiveness of applying an ES-CFD coupling simulation. These characteristics and the solution accuracy requirement determine whether a coupled simulation is needed for a specific building and which coupling method can provide the best solution with the compromise of both accuracy and efficiency. The study conducts a sensitivity analysis of the coupling simulation to the potential influential factors, based on which general suggestions on appropriate usage of the coupling simulation are provided. (author)

  13. Occupant performance and building energy consumption with different philosophies of determining acceptable thermal conditions

    DEFF Research Database (Denmark)

    Toftum, Jørn; Andersen, Rune Vinther; Jensen, Kasper Lynge

    2009-01-01

    Based on building energy and indoor environment simulations, this study uses a recently developed method relying on Bayesian Network theory to estimate and compare the consequences for occupant performance and energy consumption of applying temperature criteria set according to the adaptive model...... building configurations, especially in the tropical climate, the estimated performance differed only modestly between configurations. However, energy consumption was always lower in buildings without mechanical cooling, particularly so in the tropical climate. The findings indicate that determining...... acceptable indoor thermal environments with the adaptive comfort model may result in significant energy savings and at the same time will not have large consequences for the mental performance of occupants....

  14. Importance of thermal comfort for library building in Kuching, Sarawak

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, S.H.; Baharun, A.; Abdul Mannan, M.D.; Abang Adenan, D.A. [Department of Civil Engineering, Faculty of Engineering, University Malaysia Sarawak (UNIMAS), 94300 Kota Samarahan, Sarawak (Malaysia)

    2013-07-01

    Malaysian Government takes an initiative to provide library in housing areas to improve the quality of human capital. However, the government has to evaluate every aspect of their provision to ensure the services provided meet the demands of the users, including the aspect of thermal comfort in the building. For this study, a library constructed using Industrialised Building System (IBS) are selected for thermal comfort evaluation. The data were analyzed using Corrected Effective Temperature (CET) index. From the data analysis, it shows that thermal comfort in the library could not be achieved most of the time unless when the mechanical cooling is used. A series of technical design improvements are then recommended to improve the thermal comfort inside the library by incorporating construction details without increasing the cost.

  15. Importance of thermal comfort for library building in Kuching, Sarawak

    Directory of Open Access Journals (Sweden)

    S.H. Ibrahim, A. Baharun, M.D. Abdul Mannan, D.A. Abang Adenan

    2013-01-01

    Full Text Available Malaysian Government takes an initiative to provide library in housing areas to improve the quality of human capital. However, the government has to evaluate every aspect of their provision to ensure the services provided meet the demands of the users, including the aspect of thermal comfort in the building. For this study, a library constructed using Industrialised Building System (IBS are selected for thermal comfort evaluation. The data were analyzed using Corrected Effective Temperature (CET index. From the data analysis, it shows that thermal comfort in the library could not be achieved most of the time unless when the mechanical cooling is used. A series of technical design improvements are then recommended to improve the thermal comfort inside the library by incorporating construction details without increasing the cost.

  16. Ice slurry based thermal storage in multifunctional buildings

    Science.gov (United States)

    Wang, M. J.; Kusumoto, N.

    Ice slurry based thermal storage plays an important role in reshaping patterns of electricity use for space cooling and heating. It offers inherent advantages in energy efficiency, operating savings, load follow-up and flexible installation over conventional thermal storage technologies. This paper provides discussions on the generation mechanism and performance of ice slurry, as well as the operation principle of the ice slurry based thermal storage system. Details of the system design, control strategy and operation performance are given through a case study on a recent installation in Herbis Osaka, the largest simple building complex in Japan. An evaluation of different installations with ice slurry thermal storage reveals that it is a rewarding technology that provides significant operating savings for the building air-conditioning and improves energy utilization efficiency in modern society.

  17. Thermal analysis of the building envelope of lightweight temporary housing

    International Nuclear Information System (INIS)

    In the last few years, to meet the need of build efficient homes in a short time and with maximum constructive simplification, lightweight prefabricated building systems have proved to be particularly suitable, especially in geographical areas which must deal with emergency situations (i.e., temporary housing). In this paper the winter and summer thermal performance of a building prototype, realised with modular steel framed elements, have been studied, in both winter and summer conditions. Special attention has been paid to the optimisation of the dynamic thermal performance of the multi-layered envelope structures. The dynamic thermal behaviour of the outer wall, analysed and discussed in details in the paper, shows that it is possible to improve the performance of lightweight walls by using an optimised stratigraphy characterised by an opportune sequence of resistive and capacitive layers. The influence of inner structures (partitions, floor and roof) on the building thermal behaviour has also analyzed trough the introduction of room performance indices appropriately defined. The results of the study have been discussed with special reference to the requirements fixed by the Energy Performance Buildings European Directive (EPBDs) and the resulting implementation in Italian Legislation

  18. Indoor Thermal Environment in Tropical Climate Residential Building

    Directory of Open Access Journals (Sweden)

    Jamaludin Nazhatulzalkis

    2014-01-01

    Full Text Available Indoor thermal environment is one of the criteria in sustainable building. This criterion is important in ensuring a healthy indoor environment for the occupants. The consideration of environmental concerns at the early design stage would effectively integrate the sustainability of the building environment. Global climate changes such as global warming do affect human comfort since people spend most of their time and activities in the building. The increasing of urban population required additional housing for households, as well as places to shop, office and other facilities. Occupants are now more conscious the importance of sustainability for a better quality of life. Good thermal environment is essential for human wellness and comfort. A residential environment will influence residents’ health and safety. The global warming increase the earth’s temperature and greenhouse emission to the atmosphere cause adverse effects to the outdoor environment. Residential developments modify the materials, structure and energy balance in urban climate effects of human economic activities. As an indoor environment is influenced by the outdoor condition, the factors affecting indoor thermal environment are crucial in improving a comfortable and healthy environment in residential building. The microclimatic of a site such as temperature and relative humidity, and wind movement led to the variation of indoor thermal environment in the building.

  19. Thermal Bridges in Building Construction - Measurements and Calculations

    DEFF Research Database (Denmark)

    Rose, Jørgen

    The thesis investigates detailed calculation methods for evaluating heat loss through building envelope constructions, or more specific, thermal bridges. First a detailed description of the calculation methods, i.e. both calculation programs and guidelines, for calculating typical thermal bridges...... in building envelope constructions is given. After this a validation of both programs and guidelines is presented. The validation is performed by comparing calculated U-values with Guarded Hot Box measurements. The last part of the thesis discusses the possibilities of utilising the results of detailed...

  20. Thermal comfort and energy-efficient cooling of nonresidential buildings

    CERN Document Server

    Kalz, Doreen

    2014-01-01

    This book supports HVAC planners in reducing the cooling energy demand, improving the indoor environment and designing more cost-effective building concepts. High performance buildings have shown that it is possible to go clearly beyond the energy requirements of existing legislation and obtaining good thermal comfort. However, there is still a strong uncertainty in day-to-day practice due to the lack of legislative regulations for mixed-mode buildings which are neither only naturally ventilated nor fully air-conditioned, but use a mix of different low-energy cooling techniques. Based on the f

  1. Steel-framed buildings: Impacts of wall detail configurations on the whole wall thermal performance

    Energy Technology Data Exchange (ETDEWEB)

    Kosny, J.; Desjarlais, A.O.; Christian, J.E.

    1998-06-01

    The main objective of this paper is the influence of architectural wall details on the whole wall thermal performance. Whole wall thermal performance analysis was performed for six light gage steel-framed wall systems (some with wood components). For each wall system, all wall details were simulated using calibrated 3-D finite difference computer modeling. The thermal performance of the six steel-framed wall systems included various system details and the whole wall system thermal performance for a typical single-story ranch house. Currently, predicted heat losses through building walls are typically based on measurements of the wall system clear wall area using test methods such as ASTM C 236 or are calculated by one of the procedures recommended in the ASHRAE Handbook of Fundamentals that often is carried out for the clear wall area exclusively. In this paper, clear wall area is defined as the part of the wall system that is free of thermal anomalies due to building envelope details or thermally unaffected by intersections with other surfaces of the building envelope. Clear wall experiments or calculations normally do not include the effects of building envelope details such as corners, window and door openings, and structural intersections with roofs, floors, ceilings, and other walls. In steel-framed wall systems, these details typically consist of much more structural components than the clear wall. For this situation, the thermal properties measured or calculated for the clear wall area do not adequately represent the total wall system thermal performance. Factors that would impact the ability of today`s standard practice to accurately predict the total wall system thermal performance are the accuracy of the calculation methods, the area of the total wall that is clear wall, and the quantity and thermal performance of the various wall system details.

  2. IMPACT ON THE APPLICATION OF INSULATION IN BUILDINGS TO ACHIEVE THERMAL COMFORT (A CASE STUDY: LAUSER OFFICE BUILDING IN BANDA ACEH

    Directory of Open Access Journals (Sweden)

    Nova Purnama Lisa

    2014-12-01

    Full Text Available From the results of research studies on the impact of the use of insulation in buildings, reducing solar radiation on buildings to improve indoor comfort by applying the Principles of radiation reduction in buildings naturally using insulation application that serves as an insulator against the building materials, use of thermal insulation in particular mounted on the roof of the building and the walls are located on second floor and the third floor Lauser office building, Calculate the cooling load for each room that was on second floor and the third floor based on the geographical location or position of the building, climate data, building material data , and the intensity of the spatial characteristics which include lighting, solar radiation, user activity and electrical appliances being used. The calculation is done with the help of Ecotech v.5, 2011. The location and position on the third floor of a building with a flat roof cast concrete, so that the heat absorbed by the platform, and two times greater than the amount of heat radiation is absorbed by the material in the direction of the light falling the sun is at an angle <30°C. The simulation results on the building with the addition of thermal insulation on all walls and the roof of the inside of the foam material ultrafolmadehid, without changing the model building and similar activities in accordance with the existing condition and the condition of the room using the air conditioner at a temperature of 18-26°C, indicating a decrease in cooling load signifinikan in any space reaches 40% of the total cooling load required on the lauser office building. Comparing the simulation results Ecotech temperature v.5 2011 with field measurements as a validation of the simulation results in order to achieve thermal comfort in buildings and can menggurangi use energy consumption in buildings and can be used as a reference in planning space-based conditioning systems energy efficient.

  3. The integration of water loop heat pump and building structural thermal storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Marseille, T.J.; Schliesing, J.S.

    1990-09-01

    Commercial buildings often have extensive periods where one space needs cooling and another heating. Even more common is the need for heating during one part of the day and cooling during another in the same spaces. If a building's heating and cooling system could be integrated with the building's structural mass such that the mass can be used to collect, store, and deliver energy, significant energy might be saved. Computer models were developed to simulate this interaction for an existing office building in Seattle, Washington that has a decentralized water-source heat pump system. Metered data available for the building was used to calibrate a base'' building model (i.e., nonintegrated) prior to simulation of the integrated system. In the simulated integration strategy a secondary water loop was manifolded to the main HVAC hydronic loop. tubing in this loop was embedded in the building's concrete floor slabs. Water was routed to this loop by a controller to charge or discharge thermal energy to and from the slabs. The slabs were also in thermal communication with the conditioned spaces. Parametric studies of the building model, using weather data for five other cities in addition to Seattle, predicted that energy can be saved on cooling dominated days. On hot, dry days and during the night the cooling tower can beneficially be used as a free cooling'' source for thermally charging'' the floor slabs using cooled water. Through the development of an adaptive/predictive control strategy, annual HVAC energy savings as large as 30% appear to be possible in certain climates. 8 refs., 13 figs.

  4. The ORC method. Effective modelling of thermal performance of multilayer building components

    Energy Technology Data Exchange (ETDEWEB)

    Akander, Jan

    2000-02-01

    The ORC Method (Optimised RC-networks) provides a means of modelling one- or multidimensional heat transfer in building components, in this context within building simulation environments. The methodology is shown, primarily applied to heat transfer in multilayer building components. For multilayer building components, the analytical thermal performance is known, given layer thickness and material properties. The aim of the ORC Method is to optimise the values of the thermal resistances and heat capacities of an RC-model such as to give model performance a good agreement with the analytical performance, for a wide range of frequencies. The optimisation procedure is made in the frequency domain, where the over-all deviation between model and analytical frequency response, in terms of admittance and dynamic transmittance, is minimised. It is shown that ORC's are effective in terms of accuracy and computational time in comparison to finite difference models when used in building simulations, in this case with IDA/ICE. An ORC configuration of five mass nodes has been found to model building components in Nordic countries well, within the application of thermal comfort and energy requirement simulations. Simple RC-networks, such as the surface heat capacity and the simple R-C-configuration are not appropriate for detailed building simulation. However, these can be used as basis for defining the effective heat capacity of a building component. An approximate method is suggested on how to determine the effective heat capacity without the use of complex numbers. This entity can be calculated on basis of layer thickness and material properties with the help of two time constants. The approximate method can give inaccuracies corresponding to 20%. In-situ measurements have been carried out in an experimental building with the purpose of establishing the effective heat capacity of external building components that are subjected to normal thermal conditions. The auxiliary

  5. Thermal comfort and building energy consumption implications – A review

    International Nuclear Information System (INIS)

    Highlights: • We review studies of thermal comfort and discuss building energy use implications. • Adaptive comfort models tend to have a wider comfort temperature range. • Higher indoor temperatures would lead to fewer cooling systems and less energy use. • Socio-economic study and post-occupancy evaluation of built environment is desirable. • Important to consider future climate scenarios in heating, cooling and power schemes. - Abstract: Buildings account for about 40% of the global energy consumption and contribute over 30% of the CO2 emissions. A large proportion of this energy is used for thermal comfort in buildings. This paper reviews thermal comfort research work and discusses the implications for building energy efficiency. Predicted mean vote works well in air-conditioned spaces but not naturally ventilated buildings, whereas adaptive models tend to have a broader comfort temperature ranges. Higher indoor temperatures in summertime conditions would lead to less prevalence of cooling systems as well as less cooling requirements. Raising summer set point temperature has good energy saving potential, in that it can be applied to both new and existing buildings. Further research and development work conducive to a better understanding of thermal comfort and energy conservation in buildings have been identified and discussed. These include (i) social-economic and cultural studies in general and post-occupancy evaluation of the built environment and the corresponding energy use in particular, and (ii) consideration of future climate scenarios in the analysis of co- and tri-generation schemes for HVAC applications, fuel mix and the associated energy planning/distribution systems in response to the expected changes in heating and cooling requirements due to climate change

  6. Thermal power plant simulation and control

    CERN Document Server

    Flynn, Damian

    2013-01-01

    Contributors of world-class excellence are brought together in Thermal Power Plant Simulation and Control to illustrate how current areas of research can be applied to power plant operation, leading to enhanced unit performance, asset management andplant competitiveness through intelligent monitoring and control strategies.

  7. Simplified Building Thermal Model Used for Optimal Control of Radiant Cooling System

    Directory of Open Access Journals (Sweden)

    Lei He

    2016-01-01

    Full Text Available MPC has the ability to optimize the system operation parameters for energy conservation. Recently, it has been used in HVAC systems for saving energy, but there are very few applications in radiant cooling systems. To implement MPC in buildings with radiant terminals, the predictions of cooling load and thermal environment are indispensable. In this paper, a simplified thermal model is proposed for predicting cooling load and thermal environment in buildings with radiant floor. In this thermal model, the black-box model is introduced to derive the incident solar radiation, while the genetic algorithm is utilized to identify the parameters of the thermal model. In order to further validate this simplified thermal model, simulated results from TRNSYS are compared with those from this model and the deviation is evaluated based on coefficient of variation of root mean square (CV. The results show that the simplified model can predict the operative temperature with a CV lower than 1% and predict cooling loads with a CV lower than 10%. For the purpose of supervisory control in HVAC systems, this simplified RC thermal model has an acceptable accuracy and can be used for further MPC in buildings with radiation terminals.

  8. CALCULATION OF THE THERMAL FIELD AND THE THERMAL RESISTANCE OF BUILDINGS ENVELOPES USING THE FINITE ELEMENT METHOD

    OpenAIRE

    U. U. Liashkevich

    2015-01-01

    The method of calculation the thermal field and the thermal resistance of fragments of building envelope and developed computer calculating program are described in the article «Calculation of the thermal field and the thermal resistance of buildings envelopes using the finite element method». The main logical modules of the program are described. An example of calculation of temperature field and of the thermal resistance of element of monolithic frame building is given.

  9. Multi-parameter building thermal analysis using the lattice method for global optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Saporito, A. [Fire and Environmental Modelling Centre, Building Research Establishment, Watford (United Kingdom); Day, A.R.; Karayiannis, T.G. [School of Engineering Systems and Design, South Bank University, London (United Kingdom); Parand, F. [Centre for Construction IT, Building Research Establishment, Watford (United Kingdom)

    2000-07-01

    The energy performance in buildings is a complex function of the building form and structure, heating system, occupancy pattern, operating schedules, and external climatic conditions. Computer simulations can help understand the dynamic interactions of these parameters. However, to carry out a multi-parameter analysis for the optimisation of the building energy performance, it is necessary to reduce the large number of tests resulting from all possible parameter combinations. In this paper, the lattice method for global optimisation (LMGO) for reducing the number of tests was used. A multi-parameter study was performed to investigate the heating energy use in office buildings using the thermal simulation code APACHE (IES-FACET). From the results of the sensitivity analysis it was possible to estimate the relative importance of various energy saving features. (author)

  10. The thermal environment and occupant perceptions in European office buildings

    Energy Technology Data Exchange (ETDEWEB)

    Stoops, J.L. [Chalmers Univ. of Tech., Goeteborg (Sweden). Dept. of Building Services Engineering

    2002-02-01

    The results from a large field study of thermal comfort in European office buildings are reported. Environmental conditions and occupant perceptions were collected over fourteen months from twenty-six different office buildings located in France, Greece, Portugal, Sweden and the UK. This thesis focuses on the thermal measurements and occupant perceptions; however, some of the additional variables with strong connections to thermal sensation are also examined. A summary of human comfort is presented to help place this thesis in appropriate context. The summary presents thermal comfort issues within a broad framework of environmental comfort including physical, physiological, behavioural, psychological and other variables. A more narrowly focused overview of current thermal comfort research is also included. The work attempts to show relationships and produce useful information from the data set by using rather simple statistics and graphical methods. The objective is to quite literally use the data set to illustrate the actual thermal conditions in European office buildings and the occupant perceptions of those conditions. The data are examined in some detail with key relationships identified and explored. Significant differences between countries, both for the physical conditions and the perceptions of those conditions are identified. In addition, the variation over the course of the year for each country is explored. The variations occur in complex ways, which make simple, all encompassing explanations impossible. The nature and size of the variations make the application of simple Europe wide models of thermal comfort questionable. It appears that individuals in different European countries have different expectations for their indoor office thermal environment. This data set will be further explored in a more complete study, which will examine the other measured variables.

  11. BES with FEM: Building Energy Simulation using Finite Element Methods

    OpenAIRE

    Schijndel, van, AWM Jos

    2012-01-01

    An overall objective of energy efficiency in the built environment is to improve building and systems performances in terms of durability, comfort and economics. In order to predict, improve and meet a certain set of performance requirements related to the indoor climate of buildings and the associated energy demand, building energy simulation (BES) tools are indispensable. Due to the rapid development of FEM software and the Multiphysics approaches, it should possible to build and simulate f...

  12. BES with FEM: Building Energy Simulation using Finite Element Methods

    OpenAIRE

    van Schijndel, A. W. M.

    2016-01-01

    An overall objective of energy efficiency in the built environment is to improve building and systems performances in terms of durability, comfort and economics. In order to predict, improve and meet a certain set of performance requirements related to the indoor climate of buildings and the associated energy demand, building energy simulation (BES) tools are indispensable. Due to the rapid development of FEM software and the Multiphysics approaches, it should possible to build and simulate f...

  13. Thermal Comfort in a Naturally-Ventilated Educational Building

    Directory of Open Access Journals (Sweden)

    David Mwale Ogoli

    2012-11-01

    Full Text Available A comprehensive study of thermal comfort in a naturally ventilated education building (88,000 ft2 in a Chicago suburb will be conducted with 120 student subjects in 2007. This paper discusses some recent trends in worldwide thermal comfort studies and presents a proposal of research for this building through a series of questionnaire tables. Two research methods used inthermal comfort studies are field studies and laboratory experiments in climate-chambers. The various elements that constitute a “comfortable” thermal environment include physical factors (ambient air temperature, mean radiant temperature, air movement and humidity, personal factors(activity and clothing, classifications (gender, age, education, etc. and psychological expectations (knowledge, experience, psychological effect of visual warmth by, say, a fireplace. Comparisons are made using data gathered from Nairobi, Kenya.Keywords: Comfort, temperature, humidity and ventilation

  14. A View on Future Building System Modeling and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Wetter, Michael

    2011-04-01

    This chapter presents what a future environment for building system modeling and simulation may look like. As buildings continue to require increased performance and better comfort, their energy and control systems are becoming more integrated and complex. We therefore focus in this chapter on the modeling, simulation and analysis of building energy and control systems. Such systems can be classified as heterogeneous systems because they involve multiple domains, such as thermodynamics, fluid dynamics, heat and mass transfer, electrical systems, control systems and communication systems. Also, they typically involve multiple temporal and spatial scales, and their evolution can be described by coupled differential equations, discrete equations and events. Modeling and simulating such systems requires a higher level of abstraction and modularisation to manage the increased complexity compared to what is used in today's building simulation programs. Therefore, the trend towards more integrated building systems is likely to be a driving force for changing the status quo of today's building simulation programs. Thischapter discusses evolving modeling requirements and outlines a path toward a future environment for modeling and simulation of heterogeneous building systems.A range of topics that would require many additional pages of discussion has been omitted. Examples include computational fluid dynamics for air and particle flow in and around buildings, people movement, daylight simulation, uncertainty propagation and optimisation methods for building design and controls. For different discussions and perspectives on the future of building modeling and simulation, we refer to Sahlin (2000), Augenbroe (2001) and Malkawi and Augenbroe (2004).

  15. Building America Top Innovations 2012: House Simulation Protocols (the Building America Benchmark)

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2013-01-01

    This Building America Top Innovations profile describes the DOE-sponsored House Simulation Protocols, which have helped ensure consistent and accurate energy-efficiency assessments for tens of thousands of new and retrofit homes supported by the Building America program.

  16. Learning in a Landscape: Simulation-building as Reflexive Intervention

    CERN Document Server

    Beaulieu, Anne; Scharnhorst, Andrea

    2011-01-01

    This article makes a dual contribution to scholarship in science and technology studies (STS) on simulation-building. It both documents a specific simulation-building project, and demonstrates a concrete contribution to interdisciplinary work of STS insights. The article analyses the struggles that arise in the course of determining what counts as theory, as model and even as a simulation. Such debates are especially decisive when working across disciplinary boundaries, and their resolution is an important part of the work involved in building simulations. In particular, we show how ontological arguments about the value of simulations tend to determine the direction of simulation-building. This dynamic makes it difficult to maintain an interest in the heterogeneity of simulations and a view of simulations as unfolding scientific objects. As an outcome of our analysis of the process and reflections about interdisciplinary work around simulations, we propose a chart, as a tool to facilitate discussions about si...

  17. Modeling and optimization of energy generation and storage systems for thermal conditioning of buildings targeting conceptual building design

    Energy Technology Data Exchange (ETDEWEB)

    Grahovac, Milica

    2012-11-29

    The thermal conditioning systems are responsible for almost half of the energy consump-tion by commercial buildings. In many European countries and in the USA, buildings account for around 40% of primary energy consumption and it is therefore vital to explore further ways to reduce the HVAC (Heating, Ventilation and Air Conditioning) system energy consumption. This thesis investigates the relationship between the energy genera-tion and storage systems for thermal conditioning of buildings (shorter: primary HVAC systems) and the conceptual building design. Certain building design decisions irreversibly influence a building's energy performance and, conversely, many generation and storage components impose restrictions on building design and, by their nature, cannot be introduced at a later design stage. The objective is, firstly, to develop a method to quantify this influence, in terms of primary HVAC system dimensions, its cost, emissions and energy consumption and, secondly, to enable the use of the developed method by architects during the conceptual design. In order to account for the non-stationary effects of the intermittent renewable energy sources (RES), thermal storage and for the component part load efficiencies, a time domain system simulation is required. An abstract system simulation method is proposed based on seven pre-configured primary HVAC system models, including components such as boil-ers, chillers and cooling towers, thermal storage, solar thermal collectors, and photovoltaic modules. A control strategy is developed for each of the models and their annual quasi-stationary simulation is performed. The performance profiles obtained are then used to calculate the energy consumption, carbon emissions and costs. The annuity method has been employed to calculate the cost. Optimization is used to automatically size the HVAC systems, based on their simulation performance. Its purpose is to identify the system component dimensions that provide

  18. Simulation of thermocline thermal energy storage system using C

    Directory of Open Access Journals (Sweden)

    Meseret Tesfay

    2013-06-01

    Full Text Available Solar thermal power generation is a modern technology, which has already shown feasible results in the production of electricity. Thermal energy storage (TES is a crucial element in solar energy applications, which includes the increase of building thermal capacity, solar water heating systems for domestic use, and Concentrated Solar Thermal power plants for electricity generation. Economic, efficient and reliable thermal energy storage systems are a key need of solar thermal power plants, in order to smooth out the insolation changes during intermittent cloudy weather condition or during night period, to allow the operation. To address this goal, based on the parabolic trough power plants, sensible heat storage system with operation temperature between 300°C – 390°C can be used. The goal of this research is to design TES which can produce 1MWe. In this work simulation is performed to analyze the Liquid medium STES using C. In this case different liquid medium TESs is investigated and out of all mixed-media single-tank thermocline TES is selected and designed based on the Schumann equation. In particular, this equation is numerically solved, in order to determine energy storage, at different locations and time inside the storage tank. Finally, due to their feasibility, low cost of manufacturing and maintenance are designed and sized to the minimum possible volume.

  19. Models for describing the thermal characteristics of building components

    DEFF Research Database (Denmark)

    Jimenez, M.J.; Madsen, Henrik

    2008-01-01

    Outdoor testing of buildings and building components under real weather conditions provides useful information about their dynamic performance. Such knowledge is needed to properly characterize the heat transfer dynamics and provides useful information for implementing energy saving strategies...... of these approaches may therefore be very useful for selecting a suitable approach for each particular case. This paper presents an overview of models that can be applied for modelling the thermal characteristics of buildings and building components using data from outdoor testing. The choice of approach depends......, for example. For the analysis of these tests, dynamic analysis models and methods are required. However, a wide variety of models and methods exists, and the problem of choosing the most appropriate approach for each particular case is a non-trivial and interdisciplinary task. Knowledge of a large family...

  20. Thermal models of buildings. Determination of temperatures, heating and cooling loads. Theories, models and computer programs

    Energy Technology Data Exchange (ETDEWEB)

    Kaellblad, K.

    1998-05-01

    The need to estimate indoor temperatures, heating or cooling load and energy requirements for buildings arises in many stages of a buildings life cycle, e.g. at the early layout stage, during the design of a building and for energy retrofitting planning. Other purposes are to meet the authorities requirements given in building codes. All these situations require good calculation methods. The main purpose of this report is to present the authors work with problems related to thermal models and calculation methods for determination of temperatures and heating or cooling loads in buildings. Thus the major part of the report deals with treatment of solar radiation in glazing systems, shading of solar and sky radiation and the computer program JULOTTA used to simulate the thermal behavior of rooms and buildings. Other parts of thermal models of buildings are more briefly discussed and included in order to give an overview of existing problems and available solutions. A brief presentation of how thermal models can be built up is also given and it is a hope that the report can be useful as an introduction to this part of building physics as well as during development of calculation methods and computer programs. The report may also serve as a help for the users of energy related programs. Independent of which method or program a user choose to work with it is his or her own responsibility to understand the limits of the tool, else wrong conclusions may be drawn from the results 52 refs, 22 figs, 4 tabs

  1. Predictive Optimal Control of Active and Passive Building Thermal Storage Inventory

    Energy Technology Data Exchange (ETDEWEB)

    Gregor P. Henze; Moncef Krarti

    2005-09-30

    Cooling of commercial buildings contributes significantly to the peak demand placed on an electrical utility grid. Time-of-use electricity rates encourage shifting of electrical loads to off-peak periods at night and weekends. Buildings can respond to these pricing signals by shifting cooling-related thermal loads either by precooling the building's massive structure or the use of active thermal energy storage systems such as ice storage. While these two thermal batteries have been engaged separately in the past, this project investigated the merits of harnessing both storage media concurrently in the context of predictive optimal control. To pursue the analysis, modeling, and simulation research of Phase 1, two separate simulation environments were developed. Based on the new dynamic building simulation program EnergyPlus, a utility rate module, two thermal energy storage models were added. Also, a sequential optimization approach to the cost minimization problem using direct search, gradient-based, and dynamic programming methods was incorporated. The objective function was the total utility bill including the cost of reheat and a time-of-use electricity rate either with or without demand charges. An alternative simulation environment based on TRNSYS and Matlab was developed to allow for comparison and cross-validation with EnergyPlus. The initial evaluation of the theoretical potential of the combined optimal control assumed perfect weather prediction and match between the building model and the actual building counterpart. The analysis showed that the combined utilization leads to cost savings that is significantly greater than either storage but less than the sum of the individual savings. The findings reveal that the cooling-related on-peak electrical demand of commercial buildings can be considerably reduced. A subsequent analysis of the impact of forecasting uncertainty in the required short-term weather forecasts determined that it takes only very

  2. The integration of water loop heat pump and building structural thermal storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Marseille, T.J.; Schliesing, J.S.

    1991-10-01

    Many commercial buildings need heat in one part and, at the same time, cooling in another part. Even more common is the need for heating during one part of the day and cooling during another in the same spaces. If that energy could be shifted or stored for later use, significant energy might be saved. If a building's heating and cooling subsystems could be integrated with the building's structural mass and used to collect, store, and deliver energy, the energy might be save cost-effectively. To explore this opportunity, researchers at the Pacific Northwest Laboratory (PNL) examined the thermal interactions between the heating, ventilating, and air-conditioning (HVAC) system and the structure of a commercial building. Computer models were developed to simulate the interactions in an existing building located in Seattle, Washington, to determine how these building subsystems could be integrated to improve energy efficiency. The HVAC subsystems in the existing building were modeled. These subsystems consist of decentralized water-source heat pumps (WSHP) in a closed water loop, connected to cooling towers for heat rejection during cooling mode and boilers to augment heating. An initial base case'' computer model of the Seattle building, as-built, was developed. Metered data available for the building were used to calibrate this model to ensure that the analysis would provide information that closely reflected the operation of a real building. The HVAC system and building structure were integrated in the model using the concrete floor slabs as thermal storage media. The slabs may be actively charged during off-peak periods with the chilled water in the loop and then either actively or passively discharged into the conditioned space during peak periods. 21 refs., 37 figs., 17 tabs.

  3. Adaptive thermal comfort for buildings in Portugal based on occupants' thermal perception

    Energy Technology Data Exchange (ETDEWEB)

    Matias, L.; Pina Santos, C.; Rebelo, M. [LNEC National Laboratory for Civil Engineering, Lisbon (Portugal); Almeida, S. [FCT Foundation for Science and Technology, Lisbon (Portugal); Correia Guedes, M. [IST Higher Technical Inst., Lisbon (Portugal)

    2009-07-01

    The use of air conditioning systems in Portugal has increased in recent years. Most new service buildings are equipped with mechanical air conditioning systems, either due to commercial reasons, productivity, or due to high internal thermal loads, and solar gains through windows. However, a large percentage of older service buildings are still naturally ventilated. In ASHRAE 55 thermal comfort standard, an adaptive model was adopted as an optional method for determining acceptable thermal conditions in naturally conditioned spaces. Recently, Portugal's National Laboratory for Civil Engineering (LNEC) initiated an interdisciplinary research study in this field. The research team of physicists, social scientists, and civil engineers developed better modeling of adaptive thermal strategies. This paper described the adaptive approach that defined indoor thermal comfort requirements applicable to Portuguese buildings. The study focused on assessing, in real use conditions, indoor environments and the response of occupants of office and educational buildings, and homes for the elderly. The results were obtained from 285 field surveys carried out on 40 buildings and a set of 2367 questionnaires completed by occupants. Field surveys assessed and measured the main indoor environmental parameters during summer, winter and mid-season. This paper included the results of the analysis to the occupants' thermal perception and expectation, by relating them to both measured and collected indoor thermal environments and outdoor climate. The relation between the occupants' thermal sensation and preference was analysed for different types of activities, throughout different seasons. Results showed that occupants may tolerate broader temperature ranges than those indicated in current standards, particularly in the heating season. 10 refs., 3 tabs., 9 figs.

  4. Application of analogue techniques to the study of the thermal performance of buildings

    Energy Technology Data Exchange (ETDEWEB)

    Day, B.F.; Burberry, P.J.; Courtney, R.G. (ed.)

    1976-01-01

    For the study of the thermal behaviour of buildings, analogue computers possess several advantages over digital computers. In particular, they may be used to observe response to long runs of meteorological data. An analogue computer developed for this purpose at the University of Bristol is described. The computer has several special features. Electrical models of whole buildings may be rapidly assembled and modified, solar gain and external air temperature may be simulated, and heating systems with thermostatic control may be modelled. Energy consumption may also be monitored. The computer may also be used to simulate vapour movement and condensation. Applications of the computer have included work on the effect of thermal capacity, insulation and control systems on energy consumption, some investigations of solar heated housing, and extensive studies of the risk of condensation in roof and wall construction. The results of these and other studies will be described, and practical details of the apparatus given.

  5. On a computational model of building thermal dynamic response

    Science.gov (United States)

    Jarošová, Petra; Vala, Jiří

    2016-07-01

    Development and exploitation of advanced materials, structures and technologies in civil engineering, both for buildings with carefully controlled interior temperature and for common residential houses, together with new European and national directives and technical standards, stimulate the development of rather complex and robust, but sufficiently simple and inexpensive computational tools, supporting their design and optimization of energy consumption. This paper demonstrates the possibility of consideration of such seemingly contradictory requirements, using the simplified non-stationary thermal model of a building, motivated by the analogy with the analysis of electric circuits; certain semi-analytical forms of solutions come from the method of lines.

  6. Review on thermal performance of phase change energy storage building envelope

    Institute of Scientific and Technical Information of China (English)

    WANG Xin; ZHANG YinPing; XlAO Wei; ZENG RuoLang; ZHANG QunLi; DI HongFa

    2009-01-01

    Improving the thermal performance of building envelope is an important way to save building energy consumption. The phase change energy storage building envelope is helpful to effective use of renewable energy, reducing building operational energy consumption, increasing building thermal comfort, and reducing environment pollution and greenhouse gas emission. This paper presents the concept of ideal energy-saving building envelope, which is used to guide the building envelope material selection and thermal performance design. This paper reviews some available researches on phase change building material and phase change energy storage building envelope. At last, this paper presents some current problems needed further research.

  7. Simulation of thermocline thermal energy storage system using C

    OpenAIRE

    Meseret Tesfay; Meyyappan Venkatesan

    2013-01-01

    Solar thermal power generation is a modern technology, which has already shown feasible results in the production of electricity. Thermal energy storage (TES) is a crucial element in solar energy applications, which includes the increase of building thermal capacity, solar water heating systems for domestic use, and Concentrated Solar Thermal power plants for electricity generation. Economic, efficient and reliable thermal energy storage systems are a key need of solar thermal power plants, i...

  8. Co-simulation of innovative integrated HVAC systems in buildings

    Energy Technology Data Exchange (ETDEWEB)

    Trcka, Marija; Hensena, Jan L.M.; Wetter, Michael

    2010-06-21

    Integrated performance simulation of buildings HVAC systems can help in reducing energy consumption and increasing occupant comfort. However, no single building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to analyze integrated building systems and to enable rapid prototyping of innovative building and system technologies. One way to alleviate this problem is to use co-simulation, as an integrated approach to simulation. This article elaborates on issues important for co-simulation realization and discusses multiple possibilities to justify the particular approach implemented in the here described co-simulation prototype. The prototype is validated with the results obtained from the traditional simulation approach. It is further used in a proof-of-concept case study to demonstrate the applicability of the method and to highlight its benefits. Stability and accuracy of different coupling strategies are analyzed to give a guideline for the required coupling time step.

  9. Draught risk index tool for building energy simulations

    DEFF Research Database (Denmark)

    Vorre, Mette Havgaard; Jensen, Rasmus Lund; Nielsen, Peter V.

    2014-01-01

    Flow elements combined with a building energy simulation tool can be used to indicate areas and periods when there is a risk of draught in a room. The study tests this concept by making a tool for post-processing of data from building energy simulations. The objective is to show indications...

  10. Learning in a landscape : Simulation-building as reflexive intervention

    NARCIS (Netherlands)

    Beaulieu, Anne; Ratto, Matt; Scharnhorst, Andrea

    2013-01-01

    This article makes a dual contribution to scholarship in science and technology studies (STS) on simulation-building. It both documents a specific simulation-building project, and demonstrates a concrete contribution to interdisciplinary work of STS insights. The article analyses the struggles that

  11. Assessment of thermal insulation materials and systems for building applications

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-06-01

    The primary goal of the study was to provide a proper foundation for decision making by the federal government, industry, and consumer. The report may be used to identify areas where new test methods and standards are needed to establish new programs for improving thermal performance of buildings, and as a basis for setting new or improved standards after the recommended test programs have been completed.

  12. Assessment Framework of Building Facade in Optimizing Indoor Thermal Comfort of Green Building Index (GBI Certified Office Building

    Directory of Open Access Journals (Sweden)

    Abdul Tharim Asniza Hamimi

    2016-01-01

    Full Text Available During the past decade, the construction industry has seen a new trend in the development of “green” or “sustainable” construction concept around the world with vast support from prominent organization, together with the introduction of sustainable building codes. The establishment of green building certification systems worldwide is seen as one of the most efforts in the emerging green building movement. In order to support the development of the “green” and “sustainable” concept in Malaysia, Green Building Index (GBI was launched by the government on 21 May 2009 that created to promote sustainability in the built environment and raise awareness of environmental issues. However, the construction industry seems to have focused only on findings the “right mechanism” for an environmentally sustainable “final result” in order for the building to be certified as green with the lacking of continuous assessment on the building performance after the certifications. This study is purposely conducted to investigate the performance of various rated Green Building Index (GBI Non-Residential New Construction office buildings and the influence on Indoor Thermal Comfort (ITC of the selected buildings. The aim is to develop an assessment framework for optimum green building architectural façade to be used for office buildings in Malaysia as well as to analyse the occupants’ perception, satisfaction and performance in the selected Green Building Index (GBI rated office indoor environment. This research is still in its infancy; therefore the paper is focused on research aims, research scope and methodology, and expected deliverables for the proposed research.

  13. Thermal evaluation of vertical greenery systems for building walls

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Nyuk Hien; Kwang Tan, Alex Yong; Chen, Yu. [Department of Building, School of Design and Environment, National University of Singapore, 4 Architecture Drive, Singapore 117566 (Singapore); Sekar, Kannagi [Department of Building, School of Design and Environment, National University of Singapore, 4 Architecture Drive, Singapore 117566 (Singapore); National Parks Board, Singapore Botanic Garden, 1 Cluny Road, Singapore 259569 (Singapore); Tan, Puay Yok; Chan, Derek; Chiang, Kelly [National Parks Board, Singapore Botanic Garden, 1 Cluny Road, Singapore 259569 (Singapore); Wong, Ngian Chung [Building and Construction Authority, 5 Maxwell Road, Singapore 069110 (Singapore)

    2010-03-15

    This research involves the study of 8 different vertical greenery systems (VGSs) installed in HortPark to evaluate the thermal impacts on the performance of buildings and their immediate environment based on the surface and ambient temperatures. VGSs 3 and 4 have the best cooling efficiency according to the maximum temperature reduction of the wall and substrate surfaces. These results point to the potential thermal benefits of vertical greenery systems in reducing the surface temperature of buildings facades in the tropical climate, leading to a reduction in the cooling load and energy cost. In terms of the lowest diurnal range of average wall surface temperature fluctuation, VGSs 4 and 1 show the highest capacities. No vertical greenery system performs well in term of the diurnal range of average substrate temperature fluctuation. By limiting the diurnal fluctuation of wall surface temperatures, the lifespan of building facades is prolonged, slowing down wear and tear as well as savings in maintenance cost and the replacement of facade parts. The effects of vertical greenery systems on ambient temperature are found to depend on specific vertical greenery systems. VGS 2 has hardly any effect on the ambient temperature while the effects of VGS 4 are felt as far as 0.60 m away. Given the preponderance of wall facades in the built environment, the use of vertical greenery systems to cool the ambient temperature in building canyons is promising. Furthermore, air intakes of air-conditioning at a cooler ambient temperature translate into saving in energy cooling load. (author)

  14. Automated Comparison of Building Energy Simulation Engines (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Polly, B.; Horowitz, S.; Booten, B.; Kruis, N.; Christensen, C.

    2012-08-01

    This presentation describes the BEopt comparative test suite, which is a tool that facilitates the automated comparison of building energy simulation engines. It also demonstrates how the test suite is improving the accuracy of building energy simulation programs. Building energy simulation programs inform energy efficient design for new homes and energy efficient upgrades for existing homes. Stakeholders rely on accurate predictions from simulation programs. Previous research indicates that software tends to over-predict energy usage for poorly-insulated leaky homes. NREL is identifying, investigating, and resolving software inaccuracy issues. Comparative software testing is one method of many that NREL uses to identify potential software issues.

  15. Nuclear Thermal Rocket Element Environmental Simulator (NTREES)

    Science.gov (United States)

    Emrich, William J., Jr.

    2008-01-01

    To support the eventual development of a nuclear thermal rocket engine, a state-of-the-art experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The test device simulates the environmental conditions (minus the radiation) to which nuclear rocket fuel components will be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner as to accurately reproduce the temperatures and heat fluxes normally expected to occur as a result of nuclear fission while at the same time being exposed to flowing hydrogen. This project is referred to as the Nuclear Thermal Rocket Element Environment Simulator or NTREES. The NTREES device is located at the Marshall Space flight Center in a laboratory which has been modified to accommodate the high powers required to heat the test articles to the required temperatures and to handle the gaseous hydrogen flow required for the tests. Other modifications to the laboratory include the installation of a nitrogen gas supply system and a cooling water supply system. During the design and construction of the facility, every effort was made to comply with all pertinent regulations to provide assurance that the facility could be operated in a safe and efficient manner. The NTREES system can currently supply up to 50 kW of inductive heating to the fuel test articles, although the facility has been sized to eventually allow test article heating levels of up to several megawatts.

  16. Building and HVAC optimal control simulation. Application to an office building.

    OpenAIRE

    Kummert, Michaël; Andre, Philippe; Nicolas, Jacques

    1999-01-01

    This paper describes the methodology to apply discrete-time optimal control to a building and its HVAC installation. Simulation-based results concerning a passive solar commercial building are presented and discussed. The simulation environment includes the TRNSYS TYPE 56 as reference building model and HVAC detailed models to test the controller with realistic control signals. The optimal controller's sensitivity to meteorological forecasting quality and to other factors is analy...

  17. Advances in Thermal Insulation. Vacuum Insulation Panels and Thermal Efficiency to Reduce Energy Usage in Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Thorsell, Thomas

    2012-07-01

    We are coming to realize that there is an urgent need to reduce energy usage in buildings and it has to be done in a sustainable way. This thesis focuses on the performance of the building envelope; more precisely thermal performance of walls and super insulation material in the form of vacuum insulation. However, the building envelope is just one part of the whole building system, and super insulators have one major flaw: they are easily adversely affected by other problems in the built environment. Vacuum Insulation Panels are one fresh addition to the arsenal of insulation materials available to the building industry. They are composite material with a core and an enclosure which, as a composite, can reach thermal conductivities as low as 0.004 W/(mK). However, the exceptional performance relies on the barrier material preventing gas permeation, maintaining a near vacuum into the core and a minimized thermal bridge effect from the wrapping of barrier material round the edge of a panel. A serpentine edge is proposed to decrease the heat loss at the edge. Modeling and testing shows a reduction of 60 % if a reasonable serpentine edge is used. A diffusion model of permeation through multilayered barrier films with metallization coatings was developed to predict ultimate service life. The model combines numerical calculations with analytical field theory allowing for more precise determination than current models. The results using the proposed model indicate that it is possible to manufacture panels with lifetimes exceeding 50 years with existing manufacturing. Switching from the component scale to the building scale; an approach of integrated testing and modeling is proposed. Four wall types have been tested in a large range of environments with the aim to assess the hydrothermal nature and significance of thermal bridges and air leakages. The test procedure was also examined as a means for a more representative performance indicator than R-value (in USA). The

  18. Computer simulator for training operators of thermal cameras

    Science.gov (United States)

    Chrzanowski, Krzysztof; Krupski, Marcin

    2004-08-01

    A PC-based image generator SIMTERM developed for training operators of non-airborne military thermal imaging systems is presented in this paper. SIMTERM allows its users to generate images closely resembling thermal images of many military type targets at different scenarios obtained with the simulated thermal camera. High fidelity of simulation was achieved due to use of measurable parameters of thermal camera as input data. Two modified versions of this computer simulator developed for designers and test teams are presented, too.

  19. Evaluation of the effects of vegetation and green walls on building thermal performance and energy consumption

    Science.gov (United States)

    Susorova, Irina

    This research explored the use of vegetation in building facades as a potential solution to the problems of urban ecology and the excessive energy consumption in buildings. Vegetated facades substantially reduce building energy use, reduce the urban heat island effect, improve air quality, and increase the biodiversity of plants and animals in cities. The goal of this research was to evaluate the effects of plants on building thermal performance and energy consumption by developing a thermal model of a building facade covered with a layer of plants. The developed mathematical model accounts for thermal physical processes in a vegetated exterior wall including solar radiation, infrared radiative exchange between the facade and sky, the facade and ground, the facade and vegetation layer, convection to and from the facade, evapotranspiration from the plant layer, heat storage in the facade material, and heat conduction through the facade. The model calculates vegetated facade surface temperature and heat flux through the facade for multiple weather conditions, plant physiological characteristics, and facade parameters inputs. The model was validated with the results of a one-week long experiment measuring the thermal properties of bare and vegetated facades on the Illinois Institute of Technology campus. The experiment and subsequent sensitivity analysis demonstrated that a plant layer can effectively reduce the facade exterior surface temperature, daily temperature fluctuations, exterior wall temperature gradient, and, as a result, provide as much additional thermal insulation to the facade as a 2.5 cm layer of expanded polystyrene insulation. The vegetated facade model was also used to analyze the reduction in energy consumption in generic office and residential thermal zones for multiple parameters. The simulations showed that energy reduction could be as high as 6.2% of annual total energy use and 34.6% of cooling energy use in residential thermal zones. Overall

  20. Reducing Residential Peak Electricity Demand with Mechanical Pre-Cooling of Building Thermal Mass

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Will [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Roux, Jordan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-08-01

    This study uses an advanced airflow, energy and humidity modelling tool to evaluate the potential for residential mechanical pre-cooling of building thermal mass to shift electricity loads away from the peak electricity demand period. The focus of this study is residential buildings with low thermal mass, such as timber-frame houses typical to the US. Simulations were performed for homes in 12 US DOE climate zones. The results show that the effectiveness of mechanical pre-cooling is highly dependent on climate zone and the selected pre-cooling strategy. The expected energy trade-off between cooling peak energy savings and increased off-peak energy use is also shown.

  1. Demand Shifting with Thermal Mass in Large Commercial Buildings in a California Hot Climate Zone

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Peng; Yin, Rongxin; Brown, Carrie; Kim, DongEun

    2009-06-01

    The potential for using building thermal mass for load shifting and peak energy demand reduction has been demonstrated in a number of simulation, laboratory, and field studies. Previous Lawrence Berkeley National Laboratory research has demonstrated that the approach is very effective in cool and moderately warm climate conditions (California Climate Zones 2-4). However, this method had not been tested in hotter climate zones. This project studied the potential of pre-cooling the building early in the morning and increasing temperature setpoints during peak hours to reduce cooling-related demand in two typical office buildings in hotter California climates ? one in Visalia (CEC Climate Zone 13) and the other in San Bernardino (CEC Climate Zone 10). The conclusion of the work to date is that pre-cooling in hotter climates has similar potential to that seen previously in cool and moderate climates. All other factors being equal, results to date indicate that pre-cooling increases the depth (kW) and duration (kWh) of the possible demand shed of a given building. The effectiveness of night pre-cooling in typical office building under hot weather conditions is very limited. However, night pre-cooling is helpful for office buildings with an undersized HVAC system. Further work is required to duplicate the tests in other typical buildings and in other hot climate zones and prove that pre-cooling is truly effective.

  2. Thermal performance of integration of solar collectors and building envelopes

    Institute of Scientific and Technical Information of China (English)

    于国清; 龚小辉; 曹双华

    2009-01-01

    The integration of building with solar collector was studied. The theoretical model of integration of building envelopes and flat plate solar collectors was set up and the thermal performance of integration was studied in winter and summer,and compared to envelopes without solar collectors. The results show that the solar collection efficiency is raised in the integration of building envelopes and solar collectors with the air layer doors closed. This is true whether in winter or summer. The increment is higher as the inlet water temperature increases or the ambient temperature is low. In winter,the heat loss is significantly reduced through integration of the building envelopes and solar collectors with the closed air layer doors. The integration with the open air layer door is worse than that without collectors. In summer,the heat gains of the integration of envelopes and solar collectors are more obviously reduced than envelopes without collectors,the integration with the open air layer door is a little better than the closed one,but the difference is very small.

  3. Building energy demand aggregation and simulation tools

    DEFF Research Database (Denmark)

    Gianniou, Panagiota; Heller, Alfred; Rode, Carsten

    2015-01-01

    Nowadays, the minimization of energy consumption and the optimization of efficiency of the overall energy grid have been in the agenda of most national and international energy policies. At the same time, urbanization has put cities under the microscope towards achieving cost-effective energy...... savings due to their compact and highly dense form. Thus, accurate estimation of energy demand of cities is of high importance to policy-makers and energy planners. This calls for automated methods that can be easily expandable to higher levels of aggregation, ranging from clusters of buildings...... to neighbourhoods and cities. Buildings occupy a key place in the development of smart cities as they represent an important potential to integrate smart energy solutions. Building energy consumption affects significantly the performance of the entire energy network. Therefore, a realistic estimation...

  4. Building Performance Simulation tools for planning of energy efficiency retrofits

    OpenAIRE

    Mondrup, Thomas Fænø; Karlshøj, Jan; Vestergaard, Flemming

    2014-01-01

    Designing energy efficiency retrofits for existing buildings will bring environmental, economic, social, and health benefits. However, selecting specific retrofit strategies is complex and requires careful planning. In this study, we describe a methodology for adopting Building Performance Simulation (BPS) tools as energy and environmentally conscious decision-making aids. The methodology has been developed to screen buildings for potential improvements and to support the development of retro...

  5. Measurement, Prediction And Simulation Methods of Moisture Content In Buildings

    OpenAIRE

    Esmaeilpour, Mehrnoush

    2011-01-01

    ABSTRACT: This thesis represented some information on prediction and controlling of moisture content in buildings. Extreme disclosure to moisture is not only a common cause of major damage to building materials, it also can lead to unhealthy indoor living environments. So predicate and control moisture content provides a durable and long-term performance building with energy efficiency. Different methods (mechanical, simulation and graphical) for predicating and controlling the moisture cont...

  6. NUMERICAL SIMULATION OF TRANSIENT THERMAL FIELD IN LASER MELTING PROCESS

    Institute of Scientific and Technical Information of China (English)

    姚国凤; 陈光南

    2004-01-01

    Numerical simulation of thermal field was studied in laser processing. The 3 -D finite element model of transient thermal calculation is given by thermal conductive equation.The effects of phase transformation latent are considered. Numerical example is given to verify the model. Finally the real example of transient thermal field is given.

  7. Thermal and Daylighting Performance of Energy-Efficient Windows in Highly Glazed Residential Buildings: Case Study in Korea

    OpenAIRE

    Chang Heon Cheong; Taeyeon Kim; Seung-Bok Leigh

    2014-01-01

    Cooling load in highly glazed residential building can be excessively large due to uncontrolled solar energy entering the indoor space. This study focuses on the cooling load reduction and changes in the daylighting properties via the application of a double window system (DWS) with shading with various surface reflectivities in highly glazed residential buildings. Evaluation of thermal and daylighting performances is carried out using simulation tools. The reductions in cooling load and ener...

  8. Geometry model construction in infrared image theory simulation of buildings

    Institute of Scientific and Technical Information of China (English)

    谢鸣; 李玉秀; 徐辉; 谈和平

    2004-01-01

    Geometric model construction is the basis of infrared image theory simulation. Taking the construction of the geometric model of one building in Harbin as an example, this paper analyzes the theoretical groundings of simplification and principles of geometric model construction of buildings. It then discusses some particular treatment methods in calculating the radiation transfer coefficient in geometric model construction using the Monte Carlo Method.

  9. Computational Fluid Dynamics and Building Energy Performance Simulation

    DEFF Research Database (Denmark)

    Nielsen, Peter Vilhelm; Tryggvason, T.

    1998-01-01

    An interconnection between a building energy performance simulation program and a Computational Fluid Dynamics program (CFD) for room air distribution will be introduced for improvement of the predictions of both the energy consumption and the indoor environment. The building energy performance...

  10. Communication Capacity Building through Pharmacy Practice Simulation

    OpenAIRE

    Fejzic, Jasmina; Barker, Michelle; Hills, Ruth; Priddle, Alannah

    2016-01-01

    Objective. To examine the effectiveness of simulated learning modules (SLMs) encompassing EXcellence in Cultural Experiential Learning and Leadership (EXCELL) core competencies in enhancing pharmacy students’ professional communication skills.

  11. Empirical Validation of Building Simulation Software : Modeling of Double Facades

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Heiselberg, Per

    The work described in this report is the result of a collaborative effort of members of the International Energy Agency (IEA), Task 34/43: Testing and validation of building energy simulation tools experts group.......The work described in this report is the result of a collaborative effort of members of the International Energy Agency (IEA), Task 34/43: Testing and validation of building energy simulation tools experts group....

  12. Research on the simulation framework in Building Information Modeling

    OpenAIRE

    Liang, Nan; Xu, Hongqing; Yu, Qiong

    2012-01-01

    In recent ten years, Building Information Modeling (BIM) has been proposed and applied in the industry of architecture. For the high efficiency and visualization, BIM and correlative technologies are welcomed by architects, engineers, builders and owners, thus the technologies on modeling for design has been widely researched. However, little attention is given to simulation while simulation is an important part of design for building, maybe because it is seen as somewhat less related to the ...

  13. Thermal inertia and energy efficiency – Parametric simulation assessment on a calibrated case study

    International Nuclear Information System (INIS)

    Highlights: • We perform a parametric simulation study on a calibrated building energy model. • We introduce adaptive shadings and night free cooling in simulations. • We analyze the effect of thermal capacity on the parametric simulations results. • We recognize that cooling demand and savings scales linearly with thermal capacity. • We assess the advantage of medium-heavy over medium and light configurations. - Abstract: The reduction of energy consumption for heating and cooling services in the existing building stock is a key challenge for global sustainability today and buildings’ envelopes retrofit is one the main issues. Most of the existing buildings’ envelopes have low levels of insulation, high thermal losses due to thermal bridges and cracks, absence of appropriate solar control, etc. Further, in building refurbishment, the importance of a system level approach is often undervalued in favour of simplistic “off the shelf” efficient solutions, focused on the reduction of thermal transmittance and on the enhancement of solar control capabilities. In many cases, the importance of the dynamic thermal properties is often neglected or underestimated and the effective thermal capacity is not properly considered as one of the design parameters. The research presented aims to critically assess the influence of the dynamic thermal properties of the building fabric (roof, walls and floors) on sensible heating and cooling energy demand for a case study. The case study chosen is an existing office building which has been retrofitted in recent years and whose energy model has been calibrated according to the data collected in the monitoring process. The research illustrates the variations of the sensible thermal energy demand of the building in different retrofit scenarios, and relates them to the variations of the dynamic thermal properties of the construction components. A parametric simulation study has been performed, encompassing the use of

  14. Residential Solar-Based Seasonal Thermal Storage Systems in Cold Climates: Building Envelope and Thermal Storage

    OpenAIRE

    Alexandre Hugo; Radu Zmeureanu

    2012-01-01

    The reduction of electricity use for heating and domestic hot water in cold climates can be achieved by: (1) reducing the heating loads through the improvement of the thermal performance of house envelopes, and (2) using solar energy through a residential solar-based thermal storage system. First, this paper presents the life cycle energy and cost analysis of a typical one-storey detached house, located in Montreal, Canada. Simulation of annual energy use is performed using the TRNSYS softwar...

  15. Influence of Three Dynamic Predictive Clothing Insulation Models on Building Energy Use, HVAC Sizing and Thermal Comfort

    OpenAIRE

    Kwang Ho Lee; Stefano Schiavon

    2014-01-01

    In building energy simulation, indoor thermal comfort condition, energy use and equipment size are typically calculated based on the assumption that the clothing insulation is equal to a constant value of 0.5 clo during the cooling season and 1.0 clo during the heating season. The assumption is not reflected in practice and thus it may lead to errors. In reality, occupants frequently adjust their clothing depending on the thermal conditions, as opposed to the assumption of constant clothing ...

  16. Design of the Building Envelope: A Novel Multi-Objective Approach for the Optimization of Energy Performance and Thermal Comfort

    Directory of Open Access Journals (Sweden)

    Fabrizio Ascione

    2015-08-01

    Full Text Available According to the increasing worldwide attention to energy and the environmental performance of the building sector, building energy demand should be minimized by considering all energy uses. In this regard, the development of building components characterized by proper values of thermal transmittance, thermal capacity, and radiative properties is a key strategy to reduce the annual energy need for the microclimatic control. However, the design of the thermal characteristics of the building envelope is an arduous task, especially in temperate climates where the energy demands for space heating and cooling are balanced. This study presents a novel methodology for optimizing the thermo-physical properties of the building envelope and its coatings, in terms of thermal resistance, capacity, and radiative characteristics of exposed surfaces. A multi-objective approach is adopted in order to optimize energy performance and thermal comfort. The optimization problem is solved by means of a Genetic Algorithm implemented in MATLAB®, which is coupled with EnergyPlus for performing dynamic energy simulations. For demonstration, the methodology is applied to a residential building for two different Mediterranean climates: Naples and Istanbul. The results show that for Naples, because of the higher incidence of cooling demand, cool external coatings imply significant energy savings, whereas the insulation of walls should be high but not excessive (no more than 13–14 cm. The importance of high-reflective coating is clear also in colder Mediterranean climates, like Istanbul, although the optimal thicknesses of thermal insulation are higher (around 16–18 cm. In both climates, the thermal envelope should have a significant mass, obtainable by adopting dense and/or thick masonry layers. Globally, a careful design of the thermal envelope is always necessary in order to achieve high-efficiency buildings.

  17. Transient thermal behaviour of crumb rubber-modified concrete and implications for thermal response and energy efficiency in buildings

    International Nuclear Information System (INIS)

    Experimental data is presented for the dry and saturated steady state thermo-physical properties, and also the dynamic thermal properties, of 180, 120 and 65 mm target slump mix designs for Plain Rubberised Concrete (PRC) with varying %wt rubber substitution and aggregate replacement types (fine, coarse, and mixed). The composites had significantly lower density and thermal conductivity than plain concrete, and there was an inverse relationship between thermal admittance and (a) mix design target slump, and (b) %wt crumb rubber substitution. The thermal decrement remained almost constant, and yet the associated time lag can be increased significantly. Parametric analysis of the effects of crumb rubber substitution for a heavyweight PassivHaus standard dwelling (in non-mechanical ventilation mode) was conducted using building performance simulation. For a London (warmer) or Glasgow (cooler) climate, PRC can be used at up to 30%wt addition and all replacement types as a substitute for plain concrete without causing any significant difference in Dry Resultant Temperature (DRT) fluctuation, if used in conjunction with passive ventilation for night time cooling. However, for the same material there was a general tendency to increase the number of overheating hours in this construction type due to its greater ability to retain any stored heat energy. - Highlights: ► PRC has significantly lower density and thermal conductivity than plain concrete. ► Inverse relationship between thermal admittance and %wt crumb rubber substitution. ► Thermal decrement almost constant but associated time lag increased significantly. ► Up to 30%wt rubber used without significant difference in DRT fluctuation.

  18. Measurement and simulation of transparent building components with sun-shading; Messung und Simulation von transparenten Bauteilen mit Sonnenschutz

    Energy Technology Data Exchange (ETDEWEB)

    Simmler, H.; Manz, H.; Haas, A. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Duebendorf (Switzerland); Favarolo, P.A. [Universita Technica delle Marche, Ancona (Italy)

    2004-12-15

    This paper takes a look at the construction and simulation of modern office buildings that often feature lightweight construction and a high proportion of glazing or even double building skins completely made of glass. In particular, those thermal comfort and cooling aspects are discussed that require that the solar attributes of facade elements are taken into account. Work done at the Swiss Federal materials institute EMPA as part of the International Energy Agency's IEA Task 27 'Performance, durability and sustainability of advanced windows and solar components for building envelopes' is discussed. The properties of glazing and shading systems are presented and discussed. Results obtained by calculation are compared with those obtained from measurements. Modules for the calculation of the properties of glazing elements and their simulation are discussed, as are transparent insulation systems.

  19. Demand Shifting with Thermal Mass in Light and Heavy Mass Commercial Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Peng; Zagreus, Leah

    2009-05-01

    The potential for utilizing building thermal mass for load shifting and peak demand reduction has been demonstrated in a number of simulation, laboratory, and field studies. This project studied the potential of pre-cooling and demand limiting in a heavy mass and a light mass building in the Bay Area of California. The conclusion of the work to date is that pre-cooling has the potential to improve the demand responsiveness of commercial buildings while maintaining acceptable comfort conditions. Results indicate that pre-cooling increases the depth (kW) and duration (kWh) of the shed capacity of a given building, all other factors being equal. Due to the time necessary for pre-cooling, it is only applicable to day-ahead demand response programs. Pre-cooling can be very effective if the building mass is relatively heavy. The effectiveness of night pre-cooling under hot weather conditions has not been tested. Further work is required to quantify and demonstrate the effectiveness of pre-cooling in different climates. Research is also needed to develop screening tools that can be used to select suitable buildings and customers, identify the most appropriate pre-cooling strategies, and estimate the benefits to the customer and the utility.

  20. Thermal Performance of Building Roof with Infrared Reflective Coatings

    Institute of Scientific and Technical Information of China (English)

    SHEN Hui; TAN Hong-wei; KATSUO MIKI; LIU Xiao-yu

    2009-01-01

    This paper investigated the applicability and effects of infrared reflective coating on energy con-sumption of factory building in hot summer and warm winter zone. It first resorted to theoretical calculation, which demonstrated the beneficial effects of infrared reflective coating on reducing building energy consumption. Then it analyzed a field measurement done on two identical rooms respectively with ordinary coated roof and in-frared reflective coated roof from November 2006 to October 2007, on a 24h basis. The measured data include exterior and interior roof surface temperature, indoor air temperature, and indoor globe temperature. The relat-ed weather data is from a weather station near the measured area. The continuous measurement has been accom-plished in southern China, and the measured data indicate that roof surface temperature and heat gain are signifi-cantly decreased in summer while slight negative effects in winter are induced by adopting infrared reflective coating. Thus it is simple and applicable to reduce building energy consumption in this area by applying infrared reflective coating. Regress equation between reduced roof thermal property, such as surface temperature and heat gain, and reduction in absorbed solar radiation shows their highly linear relationship. Based on the mea-sured data, it is estimated that the reduced power consumption is 3.45 kWh/m2·month in June.

  1. Simulation of Room Climate of Public Buildings

    Directory of Open Access Journals (Sweden)

    Prorokova Maria

    2016-01-01

    Full Text Available The article presents the details of modeling of heat exchange and mass transfer in a room in the formation of a microclimate. The mathematical model is implemented in the program ANSYS Fluent and is used to predict the climate parameters after the implementation of energy saving measures in the building. Verification of the mathematical model by comparing the experimental data with the results of the measurement of microclimate parameters of the experiment.

  2. Simulation of probabilistic wind loads and building analysis

    Science.gov (United States)

    Shah, Ashwin R.; Chamis, Christos C.

    1991-01-01

    Probabilistic wind loads likely to occur on a structure during its design life are predicted. Described here is a suitable multifactor interactive equation (MFIE) model and its use in the Composite Load Spectra (CLS) computer program to simulate the wind pressure cumulative distribution functions on four sides of a building. The simulated probabilistic wind pressure load was applied to a building frame, and cumulative distribution functions of sway displacements and reliability against overturning were obtained using NESSUS (Numerical Evaluation of Stochastic Structure Under Stress), a stochastic finite element computer code. The geometry of the building and the properties of building members were also considered as random in the NESSUS analysis. The uncertainties of wind pressure, building geometry, and member section property were qualified in terms of their respective sensitivities on the structural response.

  3. Building Performance Simulation tools for planning of energy efficiency retrofits

    DEFF Research Database (Denmark)

    Mondrup, Thomas Fænø; Karlshøj, Jan; Vestergaard, Flemming

    2014-01-01

    Designing energy efficiency retrofits for existing buildings will bring environmental, economic, social, and health benefits. However, selecting specific retrofit strategies is complex and requires careful planning. In this study, we describe a methodology for adopting Building Performance...... to energy efficiency retrofits in social housing. To generate energy savings, we focus on optimizing the building envelope. We evaluate alternative building envelope actions using procedural solar radiation and daylight simulations. In addition, we identify the digital information flow and the information...... Simulation (BPS) tools as energy and environmentally conscious decision-making aids. The methodology has been developed to screen buildings for potential improvements and to support the development of retrofit strategies. We present a case study of a Danish renovation project, implementing BPS approaches...

  4. Energy Performance of a Novel System Combining Natural Ventilation with Diffuse Ceiling Inlet and Thermally Activated Building Systems (TABS)

    DEFF Research Database (Denmark)

    Yu, Tao

    saving potential and the steady-state and dynamic energy performance of this system. The presented work utilizes building simulation method to investigate the energy saving potential of this novel system. Afterwards, an experimental set-up is built in the laboratory to simulate a real office environment......As a response to new stringent energy policies in the building sector, office buildings have become well-insulated and highly-airtight, resulting in an increasing cooling need in both summer and winter. This study proposes a novel system combining natural ventilation with diffuse ceiling inlet...... and thermally activated building systems (TABS) for cooling and ventilation in future Danish office buildings. The new solution would have the special potential of using natural ventilation all year round even in the extremely cold seasons without any draught risk. The main focuses of this study are the energy...

  5. Space heating in buildings: thermal diagnosis of an industrial building; Chauffage des batiments: bilan thermique d`un batiment industriel

    Energy Technology Data Exchange (ETDEWEB)

    Brunet, R.

    1996-12-31

    The various heat transfer equations used for calculations in thermal diagnosis of an industrial building are reviewed: calculation of the heat losses through walls as a function of building materials, calculation of the energy consumption for heating fresh air (as a function of the air pollution rate in the building), calculation of the total heat losses, the heating energy demand and the annual energy consumption. Data concerning building materials characteristics, insulation and heating loads in the various regions of France, are also presented

  6. Residential Solar-Based Seasonal Thermal Storage Systems in Cold Climates: Building Envelope and Thermal Storage

    Directory of Open Access Journals (Sweden)

    Alexandre Hugo

    2012-10-01

    Full Text Available The reduction of electricity use for heating and domestic hot water in cold climates can be achieved by: (1 reducing the heating loads through the improvement of the thermal performance of house envelopes, and (2 using solar energy through a residential solar-based thermal storage system. First, this paper presents the life cycle energy and cost analysis of a typical one-storey detached house, located in Montreal, Canada. Simulation of annual energy use is performed using the TRNSYS software. Second, several design alternatives with improved thermal resistance for walls, ceiling and windows, increased overall air tightness, and increased window-to-wall ratio of South facing windows are evaluated with respect to the life cycle energy use, life cycle emissions and life cycle cost. The solution that minimizes the energy demand is chosen as a reference house for the study of long-term thermal storage. Third, the computer simulation of a solar heating system with solar thermal collectors and long-term thermal storage capacity is presented. Finally, the life cycle cost and life cycle energy use of the solar combisystem are estimated for flat-plate solar collectors and evacuated tube solar collectors, respectively, for the economic and climatic conditions of this study.

  7. Implementation of Models for Building Envelope Air Flow Fields in a Whole Building Hygrothermal Simulation Tool

    DEFF Research Database (Denmark)

    Sørensen, Karl Grau; Rode, Carsten

    2009-01-01

    phenomena that occur. However, there is still room for further development of such tools. This paper will present an attempt to integrate modelling of air flows in building envelopes into a whole building hygrothermal simulation tool. Two kinds of air flows have been considered: (1) Air flow in a ventilated...... cavity such as behind the exterior cladding of a building envelope, i.e. a flow which is parallel to the construction plane. (2) Infiltration/exfiltration of air through the building envelope, i.e. a flow which is perpendicular to the constructionplane. The paper presents the models and how they have...

  8. Sizing Thermally Activated Building Systems (TABS): A Brief Literature Review and Model Evaluation

    OpenAIRE

    Basu, Chandrayee; Schiavon, Stefano; Bauman, Fred

    2012-01-01

    While Thermally Activated Building Systems (TABS) is a recognized low-energy HVAC candidate system for net-zero-energy buildings, sizing of these systems is complex due to their slow thermal response. In this paper, seven design and control models have been reviewed and characterized systematically with an aim to investigate their applicability in various design scenarios and at different design stages. The design scenarios include variable space heat gain, different building thermal mass and...

  9. Improvement of energy performances of existing buildings by application of solar thermal systems

    OpenAIRE

    Krstić-Furundžić Aleksandra; Kosorić Vesna

    2009-01-01

    Improvement of energy performances of the existing buildings in the suburban settlement Konjarnik in Belgrade, by the application of solar thermal systems is the topic presented in this paper. Hypothetical models of building improvements are created to allow the benefits of applying solar thermal collectors to residential buildings in Belgrade climate conditions to be estimated. This case study presents different design variants of solar thermal collectors integrated into a multifamily ...

  10. Towards automatic building of continuous and discrete process simulator

    International Nuclear Information System (INIS)

    The problem to be solved is the simulation of essentially continuous processes but involving a limited number of events leading to discontinuities. The NEPTUNIX simulation package solves this problem in the folloving way: a description of the process model is made, using a non-procedural language, the model is then analysed and, if it is found correct, NEPTUNIX generates automatically the corresponding simulator. This simulator is efficient and transportable. Model description and other compiler outputs build up a complete documentation of the model, which documentation is also fundamental for easy and efficient operation of the simulator

  11. Co-Simulation of Building Energy and Control Systems with the Building Controls Virtual Test Bed

    Energy Technology Data Exchange (ETDEWEB)

    Wetter, Michael

    2010-08-22

    This article describes the implementation of the Building Controls Virtual Test Bed (BCVTB). The BCVTB is a software environment that allows connecting different simulation programs to exchange data during the time integration, and that allows conducting hardware in the loop simulation. The software architecture is a modular design based on Ptolemy II, a software environment for design and analysis of heterogeneous systems. Ptolemy II provides a graphical model building environment, synchronizes the exchanged data and visualizes the system evolution during run-time. The BCVTB provides additions to Ptolemy II that allow the run-time coupling of different simulation programs for data exchange, including EnergyPlus, MATLAB, Simulink and the Modelica modelling and simulation environment Dymola. The additions also allow executing system commands, such as a script that executes a Radiance simulation. In this article, the software architecture is presented and the mathematical model used to implement the co-simulation is discussed. The simulation program interface that the BCVTB provides is explained. The article concludes by presenting applications in which different state of the art simulation programs are linked for run-time data exchange. This link allows the use of the simulation program that is best suited for the particular problem to model building heat transfer, HVAC system dynamics and control algorithms, and to compute a solution to the coupled problem using co-simulation.

  12. Simulation based energy consumption calculation of an office building using solar-assisted air conditioning

    OpenAIRE

    Thomas, Sébastien; Andre, Philippe

    2008-01-01

    To minimize environmental impact and CO2 production associated with air-conditioning system operation, it is reasonable to evaluate the prospects of a clean energy source. The targets of the study are to evaluate cooling energy consumption to maintain thermal comfort in an office building and to point out solar energy to satisfy these cooling needs. Simulations were carried out with three different cooling systems in the same operating conditions to determine as accurately as possible the pot...

  13. Environmental and Economic Analysis of Thermal Active Building System

    Directory of Open Access Journals (Sweden)

    Paulo Fabiano Reis Lessa

    2016-05-01

    Full Text Available This paper is regarding one promising technological solution – which is so called Thermal Active Building Systems (TABS –for one of the most critical problems both in environmental and economic aspects, which is the raising energy consumption. Buildings are the principal application target of the solution once that population spends most part of their time inside them. Therefore, more energy is required to supply an increasingly demand in lighting, air conditioning, heating, electronic devices and so on. In this context, TABS emerge like a possible solution. To ensure the system efficiency or, in other words, prove its viability, it will be applied an environmental management tool (SWOT Analysis weighting all the pros and comparing with its drawbacks, based on previous experiences in implantation of such system, available in literature. A basic theoretical background, which is extremely important to a better comprehension of the system, covering both engineering and environmental management areas, is presented on this paper. Results shown that TABS are efficient mechanisms in the reduction of power consumption, committed with sustainable development, and which worth the investments in a Life Cycle Cost evaluation

  14. Working mechanism and numerical simulation of assembly coastal building techniques

    Institute of Scientific and Technical Information of China (English)

    陈育民; 刘汉龙; 陈泽

    2008-01-01

    A new coastal technique, named as assembly coastal building, was introduced. The main concept of the technique was the assembling components which could be combined and locked together to form a large caisson. The assembly coastal building technique was used in a sea access road in Zhuanghai 4X1 well, Dagang Oilfield. The design plans and in-situ tests in the sea access road project were introduced in detail. According to the Zhuanghai project, the numerical simulation method of assembly coastal building technique was proposed. 2D numerical simulations were performed in FLAC to analyze the displacement and stability of the technique in the construction process and post-construction period. The settlement calculated is close to the in-situ results, which proves that the proposed numerical method is reasonable. Results show that the assembly coastal building technique has large safety factor under the gravity loading and wave loadings.

  15. Thermal transport properties of uranium dioxide by molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Taku; Sinnott, Susan B. [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States); Tulenko, James S. [Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL 32611 (United States); Grimes, Robin W. [Department of Materials, Imperial College London, London SW7 2AZ (United Kingdom); Schelling, Patrick K. [AMPAC and Department of Physics, University of Central Florida, Orlando, FL 32816 (United States); Phillpot, Simon R. [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States)], E-mail: sphil@mse.ufl.edu

    2008-04-30

    The thermal conductivities of single crystal and polycrystalline UO{sub 2} are calculated using molecular dynamics simulations, with interatomic interactions described by two different potential models. For single crystals, the calculated thermal conductivities are found to be strongly dependent on the size of the simulation cell. However, a scaling analysis shows that the two models predict essentially identical values for the thermal conductivity for infinite system sizes. By contrast, simulations with the two potentials for identical fine polycrystalline structures yield estimated thermal conductivities that differ by a factor of two. We analyze the origin of this difference.

  16. Nuclear Thermal Rocket Simulation in NPSS

    Science.gov (United States)

    Belair, Michael L.; Sarmiento, Charles J.; Lavelle, Thomas M.

    2013-01-01

    Four nuclear thermal rocket (NTR) models have been created in the Numerical Propulsion System Simulation (NPSS) framework. The models are divided into two categories. One set is based upon the ZrC-graphite composite fuel element and tie tube-style reactor developed during the Nuclear Engine for Rocket Vehicle Application (NERVA) project in the late 1960s and early 1970s. The other reactor set is based upon a W-UO2 ceramic-metallic (CERMET) fuel element. Within each category, a small and a large thrust engine are modeled. The small engine models utilize RL-10 turbomachinery performance maps and have a thrust of approximately 33.4 kN (7,500 lbf ). The large engine models utilize scaled RL-60 turbomachinery performance maps and have a thrust of approximately 111.2 kN (25,000 lbf ). Power deposition profiles for each reactor were obtained from a detailed Monte Carlo N-Particle (MCNP5) model of the reactor cores. Performance factors such as thermodynamic state points, thrust, specific impulse, reactor power level, and maximum fuel temperature are analyzed for each engine design.

  17. Sustainable construction building performance simulation and asset and maintenance management

    CERN Document Server

    2016-01-01

    This book presents a collection of recent research works that highlight best practice solutions, case studies and practical advice on the implementation of sustainable construction techniques. It includes a set of new developments in the field of building performance simulation, building sustainability assessment, sustainable management, asset and maintenance management and service-life prediction. Accordingly, the book will appeal to a broad readership of professionals, scientists, students, practitioners, lecturers and other interested parties.

  18. Assessment of Retrofitting Measures for a Large Historic Research Facility Using a Building Energy Simulation Model

    Directory of Open Access Journals (Sweden)

    Young Tae Chae

    2016-06-01

    Full Text Available A calibrated building simulation model was developed to assess the energy performance of a large historic research building. The complexity of space functions and operational conditions with limited availability of energy meters makes it hard to understand the end-used energy consumption in detail and to identify appropriate retrofitting options for reducing energy consumption and greenhouse gas (GHG emissions. An energy simulation model was developed to study the energy usage patterns not only at a building level, but also of the internal thermal zones, and system operations. The model was validated using site measurements of energy usage and a detailed audit of the internal load conditions, system operation, and space programs to minimize the discrepancy between the documented status and actual operational conditions. Based on the results of the calibrated model and end-used energy consumption, the study proposed potential energy conservation measures (ECMs for the building envelope, HVAC system operational methods, and system replacement. It also evaluated each ECM from the perspective of both energy and utility cost saving potentials to help retrofitting plan decision making. The study shows that the energy consumption of the building was highly dominated by the thermal requirements of laboratory spaces. Among other ECMs the demand management option of overriding the setpoint temperature is the most cost effective measure.

  19. Molecular dynamics simulation of thermal conductivities of superlattice nanowires

    Institute of Scientific and Technical Information of China (English)

    杨决宽; 陈云飞; 颜景平

    2003-01-01

    Nonequilibrium molecular dynamics simulations were carried out to investigate heat transfer in superlattice nanowires. Results show that for fixed period length superlattice nanowires, the ratio of the total interfacial thermal resistance to the total thermal resistance and the effective thermal conductivities are invariant with the changes in interface numbers. Increasing the period length leads to an increase in the average interfacial thermal resistance, which indicates that the interfacial thermal resistance depends not only on the materials that constitute the alternating segments of superlattice nanowires, but also on the lattice strain throughout the segments. The modification of the lattice structure due to the lattice mismatch should be taken into account in the acoustic mismatch model. Simulation results also demonstrated the size confinement effect on the thermal conductivities for low dimensional structures, i.e. the thermal conductivities and the interfacial thermal resistance increase as the nanowire cross-sectional area increases.

  20. Communication Capacity Building through Pharmacy Practice Simulation.

    Science.gov (United States)

    Fejzic, Jasmina; Barker, Michelle; Hills, Ruth; Priddle, Alannah

    2016-03-25

    Objective. To examine the effectiveness of simulated learning modules (SLMs) encompassing EXcellence in Cultural Experiential Learning and Leadership (EXCELL) core competencies in enhancing pharmacy students' professional communication skills. Methods. Students completed three hours of preparatory lectures and eight hours of workshops comprising six SLMs themed around pharmacy practice and pharmacy placements. Each SLM comprised role-plays with actors, facilitation using EXCELL Social Interaction Maps (SIMs), and debriefing. Evaluations of SLMs included quantitative and qualitative survey responses collected before, during and after workshops, and after placements. Facilitators reflected on SLMs as a pedagogic modality. Results. Student feedback was positive about SLMs as an effective learning tool. The majority indicated areas of new learning and found SLMs enhanced their professional skills and confidence. Facilitator feedback was positive, and suggested SLM optimization strategies. Conclusion. Student and teaching team recommendations will inform future curriculum development including the optimization of SLMs in pharmacy education. PMID:27073281

  1. Design of energy-efficient buildings using interaction between Building Simulation Programme and Energy Supply Simulations for District Heating

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik; Dalla Rosa, Alessandro; Nagla, Inese

    demand density for which the connection to low-energy district heating networks is cost-effective and energy efficient. By using a dynamic energy simulation program for buildings it is possible to analyze the influence of the human behaviour for the building and link the results to the simulation program...... for district heating networks. The results show that human behaviour can lead to 50% higher heating demand and 60% higher peak loads than expected according to reference values in standardized calculation of energy demand pattern in energy-efficient buildings. The consequence is that in order to get the full...... that there is a large potential for distributing energy in areas with energy efficient buildings. As a measure for the feasibility of district heating, the linear heat density can be used as a representative value, and the results show that it is possible to supply heat with low-energy district heating networks...

  2. Real-time simulation of thermal shadows with EMIT

    Science.gov (United States)

    Klein, Andreas; Oberhofer, Stefan; Schätz, Peter; Nischwitz, Alfred; Obermeier, Paul

    2016-05-01

    Modern missile systems use infrared imaging for tracking or target detection algorithms. The development and validation processes of these missile systems need high fidelity simulations capable of stimulating the sensors in real-time with infrared image sequences from a synthetic 3D environment. The Extensible Multispectral Image Generation Toolset (EMIT) is a modular software library developed at MBDA Germany for the generation of physics-based infrared images in real-time. EMIT is able to render radiance images in full 32-bit floating point precision using state of the art computer graphics cards and advanced shader programs. An important functionality of an infrared image generation toolset is the simulation of thermal shadows as these may cause matching errors in tracking algorithms. However, for real-time simulations, such as hardware in the loop simulations (HWIL) of infrared seekers, thermal shadows are often neglected or precomputed as they require a thermal balance calculation in four-dimensions (3D geometry in one-dimensional time up to several hours in the past). In this paper we will show the novel real-time thermal simulation of EMIT. Our thermal simulation is capable of simulating thermal effects in real-time environments, such as thermal shadows resulting from the occlusion of direct and indirect irradiance. We conclude our paper with the practical use of EMIT in a missile HWIL simulation.

  3. Influence of Three Dynamic Predictive Clothing Insulation Models on Building Energy Use, HVAC Sizing and Thermal Comfort

    Directory of Open Access Journals (Sweden)

    Kwang Ho Lee

    2014-03-01

    Full Text Available In building energy simulation, indoor thermal comfort condition, energy use and equipment size are typically calculated based on the assumption that the clothing insulation is equal to a constant value of 0.5 clo during the cooling season and 1.0 clo during the heating season. The assumption is not reflected in practice and thus it may lead to errors. In reality, occupants frequently adjust their clothing depending on the thermal conditions, as opposed to the assumption of constant clothing values above, indicating that the clothing insulation variation should be captured in building simulation software to obtain more reliable and accurate results. In this study, the impact of three newly developed dynamic clothing insulation models on the building simulation is quantitatively assessed using the detailed whole-building energy simulation program, EnergyPlus version 6.0. The results showed that when the heating ventilation and air conditioning system (HVAC is controlled based on indoor temperature the dynamic clothing models do not affect indoor operative temperatures, energy consumption and equipment sizing. When the HVAC is controlled based on the PMV model the use of a fixed clothing insulation during the cooling (0.5 clo and heating (1.0 clo season leads to the incorrect estimation of the indoor operative temperatures, energy consumption and equipment sizing. The dynamic clothing models significantly (p < 0.0001 improve the ability of energy simulation tools to assess thermal comfort. The authors recommend that the dynamic clothing models should be implemented in dynamic building energy simulation software such as EnergyPlus.

  4. Thermal Properties of Lunar Regolith Simulants

    Science.gov (United States)

    Street, Kenneth; Ray, Chandra; Rickman, Doug

    2010-01-01

    Various high temperature chemical processes have been developed to extract oxygen and metals from lunar regolith. These processes are tested using terrestrial analogues of the regolith. But all practical terrestrial analogs contain H2O and/or OH-, the presence of which has substantial impact on important system behaviors. We have undertaken studies of lunar regolith simulants to determine the limits of the simulants to validate key components for human survivability during sustained presence on the moon. Differential Thermal Analysis (DTA) yields information on phase transitions and melting temperatures. Themo-Gravimetric Analysis (TGA) with mass spectrometric (MS) determination of evolved gas species yields chemical information on various oxygenated volatiles (water, carbon dioxide, sulfur oxides, nitrogen oxides and phosphorus oxides) and their evolution temperature profiles. The DTA and TGAMS studies included JSC-1A fine, NU-LHT-2M and its proposed feed stocks: anorthosite; dunite; HQ (high quality) glass and the norite from which HQ glass is produced. Fig 1 is a data profile for anorthosite. The DTA (Fig 1a) indicates exothermic transitions at 355 and 490 C and endothermic transitions at 970 and 1235 C. Below the 355 C transition, water (Molecular Weight, MW, 18 in Fig 1c) is lost accounting for approximately 0.1% mass loss due to water removal (Fig 1b). Just above 490 C a second type of water is lost, presumably bound in lattices of secondary minerals. Between 490 and the 970 transition other volatile oxides are lost including those of hydrogen (third water type), carbon (MW = 44), sulfur (MW = 64 and 80), nitrogen (MW 30 and 46) and possibly phosphorus (MW = 79, 95 or 142). Peaks at MW = 35 and 19 may be attributable to loss of chlorine and fluorine respectively. Negative peaks in the NO (MW = 30) and oxygen (MW = 32) MS profiles may indicate the production of NO2 (MW = 46). Because so many compounds are volatilized in this temperature range quantification of

  5. Methods for implementing Building Information Modeling and Building Performance Simulation approaches

    DEFF Research Database (Denmark)

    Mondrup, Thomas Fænø

    In the present thesis, a number of studies into the adoption of Building Information Modeling (BIM) and Building Performance Simulation (BPS) are presented. The thesis has two main goals. The first is to explore the benefits and challenges of adopting (a) BIM as a platform for Architecture......, Engineering, Construction, and Facility Management (AEC/ FM) communication, and (b) BPS as a platform for early-stage building performance prediction. The second is to develop (a) relevant AEC/FM communication support instruments, and (b) standardized BIM and BPS execution guidelines and information exchange...... to improve early-stage building performance prediction. However, because of complex BPS information exchange structures, the BPS process is not always practical, highlighting the need for these structures to be simplified and more, clearly articulated. In this thesis, buildingSMART standard approaches...

  6. Using passive cooling strategies to improve thermal performance and reduce energy consumption of residential buildings in U.A.E. buildings

    Directory of Open Access Journals (Sweden)

    Hanan M. Taleb

    2014-06-01

    Full Text Available Passive design responds to local climate and site conditions in order to maximise the comfort and health of building users while minimising energy use. The key to designing a passive building is to take best advantage of the local climate. Passive cooling refers to any technologies or design features adopted to reduce the temperature of buildings without the need for power consumption. Consequently, the aim of this study is to test the usefulness of applying selected passive cooling strategies to improve thermal performance and to reduce energy consumption of residential buildings in hot arid climate settings, namely Dubai, United Arab Emirates. One case building was selected and eight passive cooling strategies were applied. Energy simulation software – namely IES – was used to assess the performance of the building. Solar shading performance was also assessed using Sun Cast Analysis, as a part of the IES software. Energy reduction was achieved due to both the harnessing of natural ventilation and the minimising of heat gain in line with applying good shading devices alongside the use of double glazing. Additionally, green roofing proved its potential by acting as an effective roof insulation. The study revealed several significant findings including that the total annual energy consumption of a residential building in Dubai may be reduced by up to 23.6% when a building uses passive cooling strategies.

  7. A Software Architecture for Simulation Support in Building Automation

    Directory of Open Access Journals (Sweden)

    Sergio Leal

    2014-07-01

    Full Text Available Building automation integrates the active components in a building and, thus, has to connect components of different industries. The goal is to provide reliable and efficient operation. This paper describes how simulation can support building automation and how the deployment process of simulation assisted building control systems can be structured. We look at the process as a whole and map it to a set of formally described workflows that can partly be automated. A workbench environment supports the process execution by means of improved planning, collaboration and deployment. This framework allows integration of existing tools, as well as manual tasks, and is, therefore, many more intricate than regular software deployment tools. The complex environment of building commissioning requires expertise in different domains, especially lighting, heating, ventilation, air conditioning, measurement and control technology, as well as energy efficiency; therefore, we present a framework for building commissioning and describe a deployment process that is capable of supporting the various phases of this approach.

  8. Effective Energy Simulation and Optimal Design of Side-lit Buildings with Venetian Blinds

    Science.gov (United States)

    Cheng, Tian

    Venetian blinds are popularly used in buildings to control the amount of incoming daylight for improving visual comfort and reducing heat gains in air-conditioning systems. Studies have shown that the proper design and operation of window systems could result in significant energy savings in both lighting and cooling. However, there is no convenient computer tool that allows effective and efficient optimization of the envelope of side-lit buildings with blinds now. Three computer tools, Adeline, DOE2 and EnergyPlus widely used for the above-mentioned purpose have been experimentally examined in this study. Results indicate that the two former tools give unacceptable accuracy due to unrealistic assumptions adopted while the last one may generate large errors in certain conditions. Moreover, current computer tools have to conduct hourly energy simulations, which are not necessary for life-cycle energy analysis and optimal design, to provide annual cooling loads. This is not computationally efficient, particularly not suitable for optimal designing a building at initial stage because the impacts of many design variations and optional features have to be evaluated. A methodology is therefore developed for efficient and effective thermal and daylighting simulations and optimal design of buildings with blinds. Based on geometric optics and radiosity method, a mathematical model is developed to reasonably simulate the daylighting behaviors of venetian blinds. Indoor illuminance at any reference point can be directly and efficiently computed. They have been validated with both experiments and simulations with Radiance. Validation results show that indoor illuminances computed by the new models agree well with the measured data, and the accuracy provided by them is equivalent to that of Radiance. The computational efficiency of the new models is much higher than that of Radiance as well as EnergyPlus. Two new methods are developed for the thermal simulation of buildings. A

  9. Pseudo-Bond Graph model for the analysis of the thermal behavior of buildings

    Directory of Open Access Journals (Sweden)

    Merabtine Abdelatif

    2013-01-01

    Full Text Available In this work, a simplified graphical modeling tool, which in some extent can be considered in halfway between detailed physical and Data driven dynamic models, has been developed. This model is based on Bond Graphs approach. This approach has the potential to display explicitly the nature of power in a building system, such as a phenomenon of storage, processing and dissipating energy such as Heating, Ventilation and Air-Conditioning (HVAC systems. This paper represents the developed models of the two transient heat conduction problems corresponding to the most practical cases in building envelope, such as the heat transfer through vertical walls, roofs and slabs. The validation procedure consists of comparing the results obtained with this model with analytical solution. It has shown very good agreement between measured data and Bond Graphs model simulation. The Bond Graphs technique is then used to model the building dynamic thermal behavior over a single zone building structure and compared with a set of experimental data. An evaluation of indoor temperature was carried out in order to check our Bond Graphs model.

  10. Overcoming Microsoft Excel's Weaknesses for Crop Model Building and Simulations

    Science.gov (United States)

    Sung, Christopher Teh Boon

    2011-01-01

    Using spreadsheets such as Microsoft Excel for building crop models and running simulations can be beneficial. Excel is easy to use, powerful, and versatile, and it requires the least proficiency in computer programming compared to other programming platforms. Excel, however, has several weaknesses: it does not directly support loops for iterative…

  11. MALAYSIAN WEATHER DATA (TRY) FOR ENERGY SIMULATIONS IN BUILDINGS

    DEFF Research Database (Denmark)

    Reimann, Gregers Peter

    2001-01-01

    Detailed energy simulations for buildings in Malaysia have become possible after the recent construction of a Malaysian TRY (Test Reference Year) based on 21 years of hourly weather data from Subang Meteorological Station. The climatic parameters contained in the TRY are dry bulb temperature, wet...

  12. Improving the thermal performance of the building envelopes with the use of foam glass-ceramics

    OpenAIRE

    D.G. Portnyagin

    2015-01-01

    Recommendations on eliminating the defects of thermal insulation on the basis of the previously carried out thermal imaging surveys were given. Constructive solutions of building envelopes were proposed with regard to modeling thermal fields in ELCUT. A typical solution of thermal insulation of the basement joint is the unit exterior insulation of the basement wall to the level of the facing course bottom. This constructive solution is characterized by a significant thermal bridge, in the dir...

  13. Structural Simulations and Conservation Analysis -Historic Building Information Model (HBIM

    Directory of Open Access Journals (Sweden)

    C. Dore

    2015-02-01

    Full Text Available In this paper the current findings to date of the Historic Building Information Model (HBIM of the Four Courts in Dublin are presented. The Historic Building Information Model (HBIM forms the basis for both structural and conservation analysis to measure the impact of war damage which still impacts on the building. The laser scan survey was carried out in the summer of 2014 of the internal and external structure. After registration and processing of the laser scan survey, the HBIM was created of the damaged section of the building and is presented as two separate workflows in this paper. The first is the model created from historic data, the second a procedural and segmented model developed from laser scan survey of the war damaged drum and dome. From both models structural damage and decay simulations will be developed for documentation and conservation analysis.

  14. Bringing simulation to implementation: Presentation of a global approach in the design of passive solar buildings under humid tropical climates

    CERN Document Server

    Garde, François; Celaire, Robert

    2012-01-01

    In early 1995, a DSM pilot initiative has been launched in the French islands of Guadeloupe and Reunion through a partnership between several public and private partners (the French Public Utility EDF, the University of Reunion Island, low cost housing companies, architects, energy consultants, etc...) to set up standards to improve thermal design of new residential buildings in tropical climates. This partnership led to defining optimized bio-climatic urban planning and architectural designs featuring the use of passive cooling architectural principles (solar shading, natural ventilation) and components, as well as energy efficient systems and technologies. The design and sizing of each architectural component on internal thermal comfort in building has been assessed with a validated thermal and airflow building simulation software (CODYRUN). These technical specifications have been edited in a reference document which has been used to build over 300 new pilot dwellings through the years 1996-1998 in Reunion...

  15. Experimental and Numerical Analysis of Thermal and Hygrometric Characteristics of Building Structures Employing Recycled Plastic Aggregates and Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Francesco Colangelo

    2013-11-01

    Full Text Available The correct estimation of building energy consumptions is assuming an always increasing importance, and a detailed reproduction of building structures, with all the single components involved, is necessary to achieve this aim. In addition, the current ecological development tries to limit the use of natural raw materials as building components, in favor of alternative (waste materials, which ensure significant advantages from the economic, energetic and environmental point of views. In this work, dynamic heat and vapor transport in a typical three-dimensional (3D building structure, involving different types of environmental-friendly concrete mixtures, have been simulated by using finite elements. In particular, the authors propose to substitute part of the aggregates with plastic waste and to use a fly ash based geopolymeric binder for the production of low conductivity concrete, to be employed in eco-efficient buildings. Concrete produced with natural limestone aggregates has been considered as the reference benchmark. The whole characterization of the different types of concrete tested in the present work has been obtained through laboratory experiments. The structure taken into account in the simulations is a 3D thermal bridge, typical of building envelopes. The thermal and hygrometric transient behavior of this structure, employing plastic waste in different percentages and geopolymer concrete, has been analyzed by the authors.

  16. Numerical Simulation of Thermal Discharge Based on FVM Method

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A two-dimensional numerical model is proposed to simulate the thermal discharge from a power plant in Jiangsu Province. The equations in the model consist of two-dimensional non-steady shallow water equations and thermal waste transport equations. Finite volume method (FVM) is used to discretize the shallow water equations, and flux difference splitting (FDS) scheme is applied. The calculated area with the same temperature increment shows the effect of thermal discharge on sea water. A comparison between simulated results and the experimental data shows good agreement. It indicates that this method can give high precision in the heat transfer simulation in coastal areas.

  17. Attic extension and thermal renovation of the residential building: Case study

    Directory of Open Access Journals (Sweden)

    Jovanović-Popović Milica

    2006-01-01

    Full Text Available Buildings are the only resource growing constantly. Although relevant data for Serbia is not available, it is presumed that even more than 50% of energy production is spent on buildings in our country. This conclusion is based on two facts: the present industrial production and the state of buildings. In order to establish measures for energy efficient refurbishment, one residential building was analyzed in Belgrade. The chosen building represents the construction period when application of thermal insulation was not obligatory according to building regulation. As more than 35% of buildings were built in that period, they represent great potential for energy savings through the process of refurbishment.

  18. Behavior of nanoporous thermal barrier coatings under cyclic thermal loading. Computer-aided simulation

    International Nuclear Information System (INIS)

    The work presents the development of new algorithms for calculating the fraction of thermal energy dissipated during the irradiation on the inner surface of pores. On the basis of these algorithms, the simulation of heat transfer in three-layered systems was carried out taking into account the dissipation of thermal energy in specimens having different porosity. We have performed quantitative estimates of the portion of dissipating thermal energy and its influence on the distribution of thermal stresses in thermal barrier coating systems. It was demonstrated that the presence of pores with a large internal surface area in the intermediate layer material enables two-fold decrease of the internal thermal stresses

  19. Simulation of temperature in office with building integrated heating and cooling system

    DEFF Research Database (Denmark)

    Weitzmann, Peter

    2002-01-01

    by raising the temperature of the concrete to slightly above the desired room temperature. Another way of solving the problem of cooling is by using building integrated cooling in floors. This technique utilizes the thermal mass of concrete in the floors, by integrating PEX pipes in the floor. By maintaining...... the temperature of the concrete to a level slightly below the desired room temperature, the concrete will work as an absorber for the excess heat in the office. This can significantly reduce the need for air conditioning, which will give both improved indoor climate and lower energy costs in the building...... and thermal comfort parameters. The model is based on a numerical Finite Control Volume (FCV) method for the heat transfer in walls, ceiling, windows and floor. The model uses both convective and radiative heat transfer to the room air and between the room surfaces. The simulation model can be used...

  20. Hygrothermal Numerical Simulation Tools Applied to Building Physics

    CERN Document Server

    Delgado, João M P Q; Ramos, Nuno M M; Freitas, Vasco Peixoto

    2013-01-01

    This book presents a critical review on the development and application of hygrothermal analysis methods to simulate the coupled transport processes of Heat, Air, and Moisture (HAM) transfer for one or multidimensional cases. During the past few decades there has been relevant development in this field of study and an increase in the professional use of tools that simulate some of the physical phenomena that are involved in Heat, Air and Moisture conditions in building components or elements. Although there is a significant amount of hygrothermal models referred in the literature, the vast majority of them are not easily available to the public outside the institutions where they were developed, which restricts the analysis of this book to only 14 hygrothermal modelling tools. The special features of this book are (a) a state-of-the-art of numerical simulation tools applied to building physics, (b) the boundary conditions importance, (c) the material properties, namely, experimental methods for the measuremen...

  1. Building Interactive Simulations in Web Pages without Programming.

    Science.gov (United States)

    Mailen Kootsey, J; McAuley, Grant; Bernal, Julie

    2005-01-01

    A software system is described for building interactive simulations and other numerical calculations in Web pages. The system is based on a new Java-based software architecture named NumberLinX (NLX) that isolates each function required to build the simulation so that a library of reusable objects could be assembled. The NLX objects are integrated into a commercial Web design program for coding-free page construction. The model description is entered through a wizard-like utility program that also functions as a model editor. The complete system permits very rapid construction of interactive simulations without coding. A wide range of applications are possible with the system beyond interactive calculations, including remote data collection and processing and collaboration over a network. PMID:17282319

  2. HAM-Tools – a whole building simulation tool in Annex 41

    DEFF Research Database (Denmark)

    Kalagasidis, Angela Sasic; Rode, Carsten; Woloszyn, Monika

    2008-01-01

    HAM-Tools is a building simulation software. The main task of this tool is to simulate transfer processes related to building physics, i.e. heat, air and moisture transport in buildings and building components in operating conditions. The scope of the ECBCS Annex 41 “Whole Building Heat, Air and ...

  3. Development and validation of a new TRNSYS type for the simulation of external building walls containing PCM

    OpenAIRE

    Kuznik, F.; VIRGONE, J.; Johannes, K.

    2010-01-01

    International audience In building construction, the use of phase change materials (PCMs) allows the storage/release of energy from the solar radiation and/or internal loads. The application of such materials for lightweight construction (e.g., a wood house) makes it possible to improve thermal comfort and reduce energy consumption. However, in order to assess and optimize phase change materials included in building wall, numerical simulation is mandatory. For that purpose, a new TRNSYS Ty...

  4. Exploring design support possibilities of building performance simulation tools in building design process

    NARCIS (Netherlands)

    Harputlugil, G.U.; Bedir, M.

    2008-01-01

    Simulation is claimed to be an effective tool in building design to degrade the systems integration matter into comprehension of designers with either a tool or a process related approach. In this study, pre-design phase is considered with energy performance point of view. Aim of the study is explor

  5. Thermal calculations for the study of the heat evacuation in the vaults building of the centralised temporary storage (ATC)

    International Nuclear Information System (INIS)

    This article presents the thermal analyses of the vaults building at the future Spanish Nuclear Waste Storage facility (ATC) in which spent nuclear fuel and high activity nuclear wastes are to be stored efficiency, safety and securely. the analyses have been carried out by means of computational fluid dynamics (CFD) simulation codes, for the purpose of confirming the adequate design of the storage buildings and in order to obtain the air flow rate required to guarantee that the different thermal criteria are met. The design relies on natural convection in order to remove residual heat from the nuclear waste. The simulation model allows the designer to perform sensitivity analyses to evaluate the impact of different design parameters, to optimize the heat load per fuel canister and to provide an optimal loading plan for the facility. (Author)

  6. Simulation and Big Data Challenges in Tuning Building Energy Models

    Energy Technology Data Exchange (ETDEWEB)

    Sanyal, Jibonananda [ORNL; New, Joshua Ryan [ORNL

    2013-01-01

    EnergyPlus is the flagship building energy simulation software used to model whole building energy consumption for residential and commercial establishments. A typical input to the program often has hundreds, sometimes thousands of parameters which are typically tweaked by a buildings expert to get it right . This process can sometimes take months. Autotune is an ongoing research effort employing machine learning techniques to automate the tuning of the input parameters for an EnergyPlus input description of a building. Even with automation, the computational challenge faced to run the tuning simulation ensemble is daunting and requires the use of supercomputers to make it tractable in time. In this proposal, we describe the scope of the problem, the technical challenges faced and overcome, the machine learning techniques developed and employed, and the software infrastructure developed/in development when taking the EnergyPlus engine, which was primarily designed to run on desktops, and scaling it to run on shared memory supercomputers (Nautilus) and distributed memory supercomputers (Frost and Titan). The parametric simulations produce data in the order of tens to a couple of hundred terabytes.We describe the approaches employed to streamline and reduce bottlenecks in the workflow for this data, which is subsequently being made available for the tuning effort as well as made available publicly for open-science.

  7. Thermal Mapping Airborne Simulator for Small Satellite Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A high performance, inexpensive, airborne simulator that will serve as the prototype for a small satellite based imaging system capable of mapping thermal anomalies...

  8. EXPERIMENTAL THERMAL SIMULATION OF THE HIGH AUDIO SPEAKER

    Directory of Open Access Journals (Sweden)

    Liliana Cainiceanu

    2012-05-01

    Full Text Available This paper uses a thermal simulation model that can be applied to electromagnetic field and for the sound. Due to the symmetrical structure difuzorlui using AXI-symmetric pattern which significantly reduces computing time.

  9. Using DOE Commercial Reference Buildings for Simulation Studies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Field, K.; Deru, M.; Studer, D.

    2010-08-01

    The U.S. Department of Energy developed 256 EnergyPlus models for use in studies that aim to characterize about 70% of the U.S. commercial building stock. Sixteen building types - including restaurants, health care, schools, offices, supermarkets, retail, lodging, and warehouses - are modeled across 16 cities to represent the diversity of U.S. climate zones. Weighting factors have been developed to combine the models in proportions similar to those of the McGraw-Hill Construction Projects Starts Database for 2003-2007. This paper reviews the development and contents of these models and their applications in simulation studies.

  10. Addendum to the Building America House Simulation Protocols

    Energy Technology Data Exchange (ETDEWEB)

    Engebrecht-Metzger, C.; Wilson, E.; Horowitz, S.

    2012-12-01

    As Building America (BA) has grown to include a large and diverse cross-section of the home building and retrofit industries, it has become more important to develop accurate, consistent analysis techniques to measure progress towards the program's goals. The House Simulation Protocols (HSP) provides guidance to program partners and managers so that energy savings for new construction and retrofit projects can be compared alongside each other. The HSP provides the program with analysis methods that are proven to be effective and reliable in investigating the energy use of advanced energy systems and of entire houses.

  11. Addendum to the Building America House Simulation Protocols

    Energy Technology Data Exchange (ETDEWEB)

    Engebrecht, C. Metzger [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wilson, E. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Horowitz, S. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2012-12-01

    As DOE's Building America program has grown to include a large and diverse cross-section of the home building and retrofit industries, it has become more important to develop accurate, consistent analysis techniques to measure progress towards the program’s goals. The House Simulation Protocols (HSP) provide guidance to program partners and managers so that energy savings for new construction and retrofit projects can be compared alongside each other. The HSP provides the program with analysis methods that are proven to be effective and reliable in investigating the energy use of advanced energy systems and of entire houses.

  12. Indoor environment and energy consumption optimization using field measurements and building energy simulation

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik; Chasapis, Kleanthis; Gazovic, Libor;

    2015-01-01

    Modern buildings are usually equipped with advanced climate conditioning systems to ensure comfort of their occupants. However, analysis of their actual operation usually identifies large potential for improvements with respect to their efficiency. Present study investigated potential...... for improvements in an existing office building – a Town Hall of Viborg, Denmark. Thorough field measurements of indoor environment and occupant satisfaction survey were conducted to identify and describe indoor environmental quality problems. Collected data were also used to calibrate computer simulation model......, which was used for optimization of building’s performance. Proposed optimization scenarios bring 21-37% reduction on heating consumption and thermal comfort improvement by 7-12%. The approach (procedure) can help to optimize building operation and shorten the adjustment period....

  13. Simulation Speed Analysis and Improvements of Modelica Models for Building Energy Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Jorissen, Filip; Wetter, Michael; Helsen, Lieve

    2015-09-21

    This paper presents an approach for speeding up Modelica models. Insight is provided into how Modelica models are solved and what determines the tool’s computational speed. Aspects such as algebraic loops, code efficiency and integrator choice are discussed. This is illustrated using simple building simulation examples and Dymola. The generality of the work is in some cases verified using OpenModelica. Using this approach, a medium sized office building including building envelope, heating ventilation and air conditioning (HVAC) systems and control strategy can be simulated at a speed five hundred times faster than real time.

  14. Sustainable energy supply to very low-energy buildings by means of Micro-CHP technologies and solar thermal energy

    OpenAIRE

    Sicre, Benoit Ghislain

    2005-01-01

    Description and assessment of technology-related concepts aiming at improving the energy conservation in residential buildings. Explanation of the method and discussion of the whole-year simulation results for SOFC micro-CHP systems and Stirling engines in relation with single-family houses of different thermal insulation standards. Benchmark with conventional energy supply systems. Computation of allowable investment costs Beschreibung und Beurteilung unter technischen, ökonom...

  15. Thermal Modeling and Feedback Requirements for LIFE Neutronic Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Seifried, J E

    2009-07-15

    An initial study is performed to determine how temperature considerations affect LIFE neutronic simulations. Among other figures of merit, the isotopic mass accumulation, thermal power, tritium breeding, and criticality are analyzed. Possible fidelities of thermal modeling and degrees of coupling are explored. Lessons learned from switching and modifying nuclear datasets is communicated.

  16. Thermal simulation of storage in TSS-Galleries

    International Nuclear Information System (INIS)

    This report describes the experiment ''thermal simulation of storage in TSS-galleries'' what is been developed in salt mine of Asse, Germany. The report has 3 part: 1) Analysis of objectives and general description of boundary layers. 2) Geomechanics parameters of salt mine. 3) Thermal modelization, thermomechanics modelization and data acquisition

  17. APPLICATION OF NUMERICAL SIMULATION TO STUDY ON THERMAL CONDUCTION

    Institute of Scientific and Technical Information of China (English)

    C. Zhu; Z. Xu; D.E. Wu

    2004-01-01

    In this paper, using computer simulation and mathematic experiment method to solve the simplified one dimensional thermal conduction equation and to obtain the temperature distribution in a metal bar when its one end was heated. According to principle of hot expansion, a holograph of temperature distribution in the bar by laser holotechnique was taken. The results of numerical simulation and experiments are in good agreement and a new method for study on thermal conduction by laser holo-technique was found.

  18. Experimental study and advanced CFD simulation of fire safety performance of building external wall insulation system

    Directory of Open Access Journals (Sweden)

    Yan Zhenghua

    2013-11-01

    Full Text Available Large scale fire tests of building external wall insulation system were conducted. In the experiment, thermal-couples were mounted to measure the insulation system surface temperature and the gas temperature inside rooms at the second and third floors. Photos were also taken during the fire tests. The measurement provides information of the ignition and fire spread of the external insulation system which consists of surface protection layer, glass fibre net, bonding thin layer, anchor and the load bearing wall. Comprehensive simulations of the fire tests were carried out using an advanced CFD fire simulation software Simtec (Simulation of Thermal Engineering Complex [1, 2], which is now released by Simtec Soft Sweden, with the turbulent flow, turbulent combustion, thermal radiation, soot formation, convective heat transfer, the fully coupled three dimensional heat transfer inside solid materials, the ‘burn-out' of the surface protection layer and the pyrolysis of the insulation layer, etc, all computed. The simulation is compared with experimental measurement for validation. The simulation well captured the burning and fire spread of the external insulation wall.

  19. Building Behavior Simulation by Means of Artificial Neural Network in Summer Conditions

    Directory of Open Access Journals (Sweden)

    Cinzia Buratti

    2014-08-01

    Full Text Available Many studies in Italy showed that buildings are responsible for about 40% of total energy consumption, due to worsening performance of building envelope; in fact, a great number of Italian buildings were built before the 1970s and 80s. In particular, the energy consumptions for cooling are considerably increased with respect to the ones for heating. In order to reduce the cooling energy demand, ensuring indoor thermal comfort, a careful study on building envelope performance is necessary. Different dynamic software could be used in order to evaluate and to improve the building envelope during the cooling period, but much time and an accurate validation of the model are required. However, when a wide experimental data is available, the Artificial Neural Network (ANN can be an alternative, simple and fast tool to use. In the present study, the indoor thermal conditions in many dwellings built in Umbria Region were investigated in order to evaluate the envelope performance. They were recently built and have very low energy consumptions. Based on the experimental data, a feed forward network was trained, in order to evaluate the different envelopes performance. As input parameters the outdoor climatic conditions and the thermal characteristics of building envelopes were set, while, as a target parameter, the indoor air temperature was provided. A good training of network was obtained with a high regression value (0.9625 and a very small error (0.007 °C on air temperature. The network was also used to simulate the envelope behavior with new innovative glazing systems, in order to evaluate and to improve the energy performance.

  20. Analysis of thermal field within an urban canyon with variable thermophysical characteristics of the building's walls

    Science.gov (United States)

    De Lieto Vollaro, A.; Galli, G.; Vallati, A.; Romagnoli, R.

    2015-11-01

    In a typical urban configuration, a microclimatic analysis has been carried out. Using a CFD method, a N-S oriented urban street canyon, with a given H/W ratio, has been examined. The standard k-ε turbulence model has been used to simulate a three-dimensional flow field and to calculate the thermo-fluid dynamics parameters that characterize the street canyon. In this study has been analyzed the thermal flow field when the walls of the building change the properties of solar radiation absorption, in particular for α=0.2 and α=0.8. Solar radiation considered is that of 21/07 in Milan in two different hours: at 11:00 a.m. and at 02:00 p.m. The study shows the importance of the thermophysical properties of a wall, in the development of the thermal field and flow field. This is a very important topic, in terms of improvement of wellbeing and the quality of the air within the cities, through the choice of materials and colors of the facades of buildings.

  1. Design and Test of Advanced Thermal Simulators for an Alkali Metal-Cooled Reactor Simulator

    Science.gov (United States)

    Garber, Anne E.; Dickens, Ricky E.

    2011-01-01

    The Early Flight Fission Test Facility (EFF-TF) at NASA Marshall Space Flight Center (MSFC) has as one of its primary missions the development and testing of fission reactor simulators for space applications. A key component in these simulated reactors is the thermal simulator, designed to closely mimic the form and function of a nuclear fuel pin using electric heating. Continuing effort has been made to design simple, robust, inexpensive thermal simulators that closely match the steady-state and transient performance of a nuclear fuel pin. A series of these simulators have been designed, developed, fabricated and tested individually and in a number of simulated reactor systems at the EFF-TF. The purpose of the thermal simulators developed under the Fission Surface Power (FSP) task is to ensure that non-nuclear testing can be performed at sufficiently high fidelity to allow a cost-effective qualification and acceptance strategy to be used. Prototype thermal simulator design is founded on the baseline Fission Surface Power reactor design. Recent efforts have been focused on the design, fabrication and test of a prototype thermal simulator appropriate for use in the Technology Demonstration Unit (TDU). While designing the thermal simulators described in this paper, effort were made to improve the axial power profile matching of the thermal simulators. Simultaneously, a search was conducted for graphite materials with higher resistivities than had been employed in the past. The combination of these two efforts resulted in the creation of thermal simulators with power capacities of 2300-3300 W per unit. Six of these elements were installed in a simulated core and tested in the alkali metal-cooled Fission Surface Power Primary Test Circuit (FSP-PTC) at a variety of liquid metal flow rates and temperatures. This paper documents the design of the thermal simulators, test program, and test results.

  2. Experimental and Numerical Analysis of Air Flow, Heat Transfer and Thermal Comfort in Buildings with Different Heating Systems

    Directory of Open Access Journals (Sweden)

    Sabanskis A.

    2016-04-01

    Full Text Available Monitoring of temperature, humidity and air flow velocity is performed in 5 experimental buildings with the inner size of 3×3×3 m3 located in Riga, Latvia. The buildings are equipped with different heating systems, such as an air-air heat pump, air-water heat pump, capillary heating mat on the ceiling and electric heater. Numerical simulation of air flow and heat transfer by convection, conduction and radiation is carried out using OpenFOAM software and compared with experimental data. Results are analysed regarding the temperature and air flow distribution as well as thermal comfort.

  3. Experimental and Numerical Analysis of Air Flow, Heat Transfer and Thermal Comfort in Buildings with Different Heating Systems

    Science.gov (United States)

    Sabanskis, A.; Virbulis, J.

    2016-04-01

    Monitoring of temperature, humidity and air flow velocity is performed in 5 experimental buildings with the inner size of 3×3×3 m3 located in Riga, Latvia. The buildings are equipped with different heating systems, such as an air-air heat pump, air-water heat pump, capillary heating mat on the ceiling and electric heater. Numerical simulation of air flow and heat transfer by convection, conduction and radiation is carried out using OpenFOAM software and compared with experimental data. Results are analysed regarding the temperature and air flow distribution as well as thermal comfort.

  4. Improvement of energy performances of existing buildings by application of solar thermal systems

    Directory of Open Access Journals (Sweden)

    Krstić-Furundžić Aleksandra

    2009-01-01

    Full Text Available Improvement of energy performances of the existing buildings in the suburban settlement Konjarnik in Belgrade, by the application of solar thermal systems is the topic presented in this paper. Hypothetical models of building improvements are created to allow the benefits of applying solar thermal collectors to residential buildings in Belgrade climate conditions to be estimated. This case study presents different design variants of solar thermal collectors integrated into a multifamily building envelope. The following aspects of solar thermal systems integration are analyzed in the paper: energy, architectural, ecological and economic. The results show that in Belgrade climatic conditions significant energy savings and reduction of CO2 emissions can be obtained with the application of solar thermal collectors.

  5. Numerical simulation and exergetic analysis of building ventilation solar chimneys

    International Nuclear Information System (INIS)

    Highlights: • Exergetic analysis of a building ventilation solar chimney. • Numerical CFD model developed, validated and employed to study the flow. • Analysis of the solar chimney energy and exergy efficiencies. • Mechanical and thermal exergy distributions have been analysed. • Crucial points in the chimney identified to improve its performance. - Abstract: The solar chimneys used in buildings are passive solar devices which improve natural ventilation. A detailed exergetic analysis has been developed in this work, both for general balance and specific variables. To apply this analysis, a three-dimensional CFD model has been built and validated with bibliographic experimental data. The values of the variables have been examined both inside and at the exit of the solar chimney, resulting in a detailed description of the inner phenomena and parameters influencing the exergetic efficiency. The results of this study offer new tools: a numerical methodology and an exergetic analysis, to improve the design of building ventilation solar chimneys. It also affords a deeper understanding of the thermal and fluid-dynamic behaviour, and suggests some qualitative improvements. However, the numerical data obtained from the case studied, show that solar chimneys as natural ventilation systems offer quite a small efficiency and will remain within the sphere of architectural decisions

  6. Synergetic Effect between Lighting Efficiency Enhancement and Building Energy Reduction Using Alternative Thermal Operating System of Indoor LED Lighting

    Directory of Open Access Journals (Sweden)

    Byung-Lip Ahn

    2015-08-01

    Full Text Available We investigated the synergetic effect between light-emitting diode (LED lighting efficiency and building energy savings in heating and cooling using an alternative thermal operating system (ATOS of indoor LED lighting integrated with the ventilation system of a building as an active cooling device. The heat generated from LED lighting and the indoor lighting illuminance were experimentally determined. The indoor heat gains in cooling and heating periods were determined using measurement data; the annual energy savings of an office building in heating and cooling were calculated through simulation. The LED lighting illuminance increased by approximately 40% and the lighting contribution for indoor heat gain was 7.8% in summer, while 69.8% in winter with the ATOS. Consequently, the annual total energy use of the office building could be reduced by 5.9%; the energy use in cooling and heating was reduced by 18.4% and 3.3%, respectively.

  7. Impact of the U.S. National Building Information Model Standard (NBIMS) on Building Energy Performance Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Bazjanac, Vladimir

    2007-08-01

    The U.S. National Institute for Building Sciences (NIBS) started the development of the National Building Information Model Standard (NBIMS). Its goal is to define standard sets of data required to describe any given building in necessary detail so that any given AECO industry discipline application can find needed data at any point in the building lifecycle. This will include all data that are used in or are pertinent to building energy performance simulation and analysis. This paper describes the background that lead to the development of NBIMS, its goals and development methodology, its Part 1 (Version 1.0), and its probable impact on building energy performance simulation and analysis.

  8. Computer Simulation in Problems of Thermal Strength

    Directory of Open Access Journals (Sweden)

    Olga I. Chelyapina

    2012-05-01

    Full Text Available This article discusses informative technology of using graphical programming environment LabVIEW 2009 when calculating and predicting the thermal strength of materials with an inhomogeneous structure. Algorithm for processing the experimental data was developed as part of the problem.

  9. Development and validation of a new TRNSYS type for the simulation of external building walls containing PCM

    Energy Technology Data Exchange (ETDEWEB)

    Kuznik, Frederic; Virgone, Joseph; Johannes, Kevyn [Universite de Lyon, CNRS, INSA de Lyon, CETHIL, UMR 5008, F-69621 Villeurbanne, France Universite Lyon 1, F-69622 (France)

    2010-07-15

    In building construction, the use of phase change materials (PCMs) allows the storage/release of energy from the solar radiation and/or internal loads. The application of such materials for lightweight construction (e.g., a wood house) makes it possible to improve thermal comfort and reduce energy consumption. However, in order to assess and optimize phase change materials included in building wall, numerical simulation is mandatory. For that purpose, a new TRNSYS Type, named Type 260, is developed to model the thermal behavior of an external wall with PCM. This model is presented in this paper and validated using experimental data from the literature. (author)

  10. Regulation and control of thermally activated building systems; Regelung und Steuerung von thermoaktiven Bauteilsystemen

    Energy Technology Data Exchange (ETDEWEB)

    Toedtli, Juerg [Consulting Juerg Toedtli, Zuerich (Switzerland); Gwerder, Markus; Renggli, Franz; Guentensperger, Werner [Siemens Building Technologies, Zug (Switzerland); Lehmann, Beat; Dorer, Viktor [EMPA, Duebendorf (Switzerland). Abt. Building Technologies; Hildebrand, Kurt [Hochschule Luzern - Technik und Architektur, Horw (Switzerland)

    2009-11-15

    Thermally activated building systems (TABS) are becoming increasingly important in terms of energy efficient cooling and heating of buildings. In practice, however, regulation and control of such systems often causes problems. Started five years ago with the aim of getting to grips with these problems, the TABS Control research project was completed in early 2009. The project yielded the following results: various models and simulation programs for TABS; performance-bound calculations for regulating zones; a range of zone regulation/control strategies for planners to choose from, including good solutions for automatic switching between heating and cooling, for pulsed operation of the zone pump and for room temperature control; the implementation of a subset of these strategies as standard solutions in a Siemens building automation system; laboratory tests on these strategies; a new procedure for the integrated planning of TABS and their regulation/control (referred to as UBB planning procedure - Unknown But Bounded); an Excel planning tool; guidelines on selecting the hydraulic switching topology; a method for operation optimization; the theoretical basis for the new integrated planning procedure and the new regulation/ control strategies; a patent application.

  11. Performance Evaluation of Modern Building Thermal Envelope Designs in the Semi-Arid Continental Climate of Tehran

    Directory of Open Access Journals (Sweden)

    Shaghayegh Mohammad

    2013-10-01

    Full Text Available In this paper we evaluate the thermal performance of a range of modern wall constructions used in the residential buildings of Tehran in order to find the most appropriate alternative to the traditional un-fired clay and brick materials, which are increasingly being replaced in favor of more slender wall constructions employing hollow clay, autoclaved aerated concrete or light expanded clay aggregate blocks. The importance of improving the building envelope through estimating the potential for energy saving due to the application of the most energy-efficient wall type is presented and the wall constructions currently erected in Tehran are introduced along with their dynamic and steady-state thermal properties. The application of a dynamic simulation tool is explained and the output of the thermal simulation model is compared with the dynamic thermal properties of the wall constructions to assess their performance in summer and in winter. Finally, the best and worst wall type in terms of their cyclic thermal performance and their ability to moderate outdoor conditions is identified through comparison of the predicted indoor temperature and a target comfort temperature.

  12. GENERIC BUILDING BLOCKS FOR SIMULATION MODELLING OF STOCHASTIC CONTINUOUS SYSTEMS♣

    Directory of Open Access Journals (Sweden)

    M. Albertyn

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: The key objective is to present the generic building blocks of a methodology that can be used to model stochastic continuous systems efficiently. The original simulation model of a real-world system is used as the basis for the development of a generic modelling methodology. The generic building blocks of the methodology are used to construct two new simulation models using two different simulation software packages (Arena and Simul8. The evaluation method, the determination of adequate sample sizes and the verification and validation of the models are discussed. The models and software packages are compared and conclusions are presented.

    AFRIKAANSE OPSOMMING: Die hoofdoelwit is om die generiese boublokke van ‘n metodiek voor te hou wat gebruik kan word om stogastiese kontinue stelsels doeltreffend te modelleer. Die oorspronklike simulasiemodel van ‘n werklike-wêreld-stelsel word gebruik as die basis vir die ontwikkeling van ‘n generiese modelleringsmetodiek. Die generiese boublokke van die metodiek word gebruik om twee nuwe simulasiemodelle te konstrueer met twee verskillende simulasiesagtewarepakkette (Arena en Simul8. Die evaluasiemetode, die vasstelling van voldoende monstergroottes en die verifikasie en validering van die modelle word bespreek. Die modelle en sagtewarepakkette word vergelyk en gevolgtrekkings word voorgehou.

  13. Simulation of thermal-well sucker-rod pumping

    Energy Technology Data Exchange (ETDEWEB)

    Wong, A. (Alberta Oil Sands Technology and Research Authority (CA)); Sudol, T.A. (Alberta Research Council (CA))

    1992-05-01

    A major problem experienced in pumping thermal wells is low volumetric efficiencies resulting from steam and noncondensable gas interference. This paper examines the results of physical simulations performed on a full-scale sucker-rod pump test facility and numerical simulations that used an equation of state (EOS) to predict theoretical volumetric pump efficiencies.

  14. Savings in Cooling Energy with a Thermal Management System for LED Lighting in Office Buildings

    Directory of Open Access Journals (Sweden)

    Byung-Lip Ahn

    2015-06-01

    Full Text Available Light-emitting diode (LED lighting should be considered for lighting efficiency enhancement, however, waste heat from light-emitting diode (LED lighting increases the internal cooling load during the summer season. In order to solve this problem we propose a thermal management system for light-emitting diode (LED lighting with a heat exchanger module integrated with the building’s heating, ventilation, and air conditioning (HVAC system to move the lighting’s waste heat outdoors. An experiment was carried out to investigate the thermal effects in a test chamber and the heat exchange rate between the heat sink and the duct air. The heat generated by the light-emitting diode (LED lighting was calculated as 78.1% of light-emitting diode (LED input power and the heat exchange rate of the lighting heat exchange module was estimated to be between 86.5% and 98.1% according to the light-emitting diode (LED input power and the flow rate of air passing the heat sink. As a result, the average light-emitting diode (LED lighting heat contribution rate for internal heat gain was determined as 0.05; this value was used to calculate the heating and cooling energy demand of the office building through an energy simulation program. In the simulation results, the cooling energy demand was reduced by 19.2% compared with the case of conventionally installed light-emitting diode (LED lighting.

  15. Applying measured reflection from the ground to simulations of thermal perfromance of solar collectors

    DEFF Research Database (Denmark)

    Dragsted, Janne; Furbo, Simon

    2009-01-01

    and the azimuth of the surface in question. The paper will present an analysis of simulations of the thermal performance of solar collectors using the standard description of the albedo and using the albedo determined by the measurements. It will be elucidated how important an accurate description...... of the reflection from the ground is for the thermal performance of solar collectors.......Solar radiation on tilted and vertical surfaces in the Arctic is, in large parts of the year, strongly influenced by reflection from snow. In connection with planning and optimization of energy efficient buildings and solar energy systems in the Arctic, it is important to have an accurate...

  16. Thermal Performance Analysis of Solar Collectors Installed for Combisystem in the Apartment Building

    Science.gov (United States)

    Žandeckis, A.; Timma, L.; Blumberga, D.; Rochas, C.; Rošā, M.

    2012-01-01

    The paper focuses on the application of wood pellet and solar combisystem for space heating and hot water preparation at apartment buildings under the climate of Northern Europe. A pilot project has been implemented in the city of Sigulda (N 57° 09.410 E 024° 52.194), Latvia. The system was designed and optimised using TRNSYS - a dynamic simulation tool. The pilot project was continuously monitored. To the analysis the heat transfer fluid flow rate and the influence of the inlet temperature on the performance of solar collectors were subjected. The thermal performance of a solar collector loop was studied using a direct method. A multiple regression analysis was carried out using STATGRAPHICS Centurion 16.1.15 with the aim to identify the operational and weather parameters of the system which cause the strongest influence on the collector's performance. The parameters to be used for the system's optimisation have been evaluated.

  17. Equipping simulators with an advanced thermal hydraulics model EDF's experience

    International Nuclear Information System (INIS)

    The development of an accelerated version of the advanced CATHARe-1 thermal hydraulics code designed for EDF training simulators (CATHARE-SIMU) was successfully completed as early as 1991. Its successful integration as the principal model of the SIPA Post-Accident Simulator meant that its use could be extended to full-scale simulators as part of the renovation of the stock of existing simulators. In order to further extend the field of application to accidents occurring in shutdown states requiring action and to catch up with developments in respect of the CATHARE code, EDF initiated the SCAR Project designed to adapt CATHARE-2 to simulator requirements (acceleration, parallelization of the computation and extension of the simulation range). In other respects, the installation of SIPA on workstations means that the authors can envisage the application of this remarkable training facility to the understanding of thermal hydraulics accident phenomena

  18. Deterministic simulation of thermal neutron radiography and tomography

    Science.gov (United States)

    Pal Chowdhury, Rajarshi; Liu, Xin

    2016-05-01

    In recent years, thermal neutron radiography and tomography have gained much attention as one of the nondestructive testing methods. However, the application of thermal neutron radiography and tomography is hindered by their technical complexity, radiation shielding, and time-consuming data collection processes. Monte Carlo simulations have been developed in the past to improve the neutron imaging facility's ability. In this paper, a new deterministic simulation approach has been proposed and demonstrated to simulate neutron radiographs numerically using a ray tracing algorithm. This approach has made the simulation of neutron radiographs much faster than by previously used stochastic methods (i.e., Monte Carlo methods). The major problem with neutron radiography and tomography simulation is finding a suitable scatter model. In this paper, an analytic scatter model has been proposed that is validated by a Monte Carlo simulation.

  19. Assessment of the thermal environment in a simulated aircraft cabin using thermal manikin exposure

    DEFF Research Database (Denmark)

    Strøm-Tejsen, Peter; Zukowska, Daria; Jama, Agnieszka;

    2007-01-01

    The thermal environment in a full-scale 21-seat section of an aircraft cabin installed in a climate chamber was investigated. Fourteen heated cylinders and two thermal manikins were used to simulate the heat load, buoyancy flow and flow obstruction from passengers in the cabin. Measurements were...

  20. The Effect of Passive Design Strategies on Thermal Performance of Female Secondary School Buildings during Warm Season in Hot Dry Climate

    Directory of Open Access Journals (Sweden)

    Sahar eZahiri

    2016-03-01

    Full Text Available This paper describes a series of field studies and simulation analysis to improve the thermal performance of school buildings in the city of Tehran in Iran during warm season. The field studies used on-site measurement and questionnaire-based survey in the warm spring season in a typical female secondary school building. The on-site monitoring assessed the indoor air temperature and humidity levels of six classrooms while the occupants completed questionnaires covering their thermal sensations and thermal preferences. Moreover, thermal simulation analysis was also carried out to evaluate and improve the thermal performance of the classrooms based on the students’ thermal requirements and passive design strategies. In this study, the environmental design guidelines for female secondary school buildings were introduced for the hot and dry climate of Tehran, using passive design strategies. The study shows that the application of passive design strategies including south and south-east orientation, 10cm thermal insulation in wall and 5cm in the roof, and the combination of 30cm side fins and overhangs as a solar shading devices, as well as all-day ventilation strategy and the use of thermal mass materials with 25cm-30cm thickness, has considerable impact on indoor air temperatures in warm season in Tehran and keeps the indoor environment in an acceptable thermal condition. The results of the field studies also indicated that most of the occupants found their thermal environment not to be comfortable and the simulation results showed that passive design techniques had a significant influence on the indoor air temperature and can keep it in an acceptable range based on the female students’ thermal requirement. Therefore, in order to enhance the indoor environment and to increase the learning performance of the students, it is necessary to use the appropriate passive design strategies, which also reduce the need for mechanical systems and

  1. 3D thermal climate monitoring in factory buildings

    NARCIS (Netherlands)

    Posselt, G.; Booij, P.S.; Thiede, S.; Fransman, J.E.; Driessen, B.J.F.; Herrmann, C.

    2015-01-01

    Guaranteeing defined conditions, such as the temperature levels inside the factory's building shell, is often important to produce high-quality products. Heating, ventilation and air conditioning (HVAC) equipment, as part of the technical building services, is energy intensive and accounts for a maj

  2. Modeling And Predictive Control Of High Performance Buildings With Distributed Energy Generation And Thermal Storage

    OpenAIRE

    Li, Siwei; Karava, Panagiota

    2014-01-01

    Building-integrated photovoltaic-thermal (BIPV/T) systems replace conventional building cladding with solar technology that generates electricity and heat. For example, unglazed transpired solar collectors, known as UTCs, can be integrated with open-loop photovoltaic thermal (PV/T) systems to preheat ventilation air and/or to feed hot air into an air source heat pump, thus satisfying a significant part of the building’s heating and/or hot water requirements while also generating electricity. ...

  3. Building Software for Simulation Theory and Algorithms, with Applications in C++

    CERN Document Server

    Nutaro, James

    2010-01-01

    This book offers a concise introduction to the art of building simulation software. It clearly demonstrates the five skills necessary for building simulations of complicated systems: abstractions for simulation dynamic systems; basic simulation algorithms for continuous and discrete event simulations; combining continuous and discrete event simulations into a coherent whole; strategies for testing a simulation; and theoretical foundations of the modeling constructs and simulation algorithms. This is indispensable reading for software programmers, developers, and engineers, and students in rela

  4. Assessment of the Portuguese building thermal code: Newly revised requirements for cooling energy needs used to prevent the overheating of buildings in the summer

    International Nuclear Information System (INIS)

    In this paper, cooling energy needs are calculated by the steady-state methodology of the Portuguese building thermal code. After the first period of building code implementation, re-evaluation according to EN ISO 13790 is recommended in order to compare results with the dynamic simulation results. From these analyses, a newly revised methodology arises including a few corrections in procedure. This iterative result is sufficiently accurate to calculate the building's cooling energy needs. Secondly, results show that the required conditions are insufficient to prevent overheating. The use of the gain utilization factor as an overheating risk index is suggested, according to an adaptive comfort protocol, and is integrated in the method used to calculate the maximum value for cooling energy needs. This proposed streamlined method depends on reference values: window-to-floor area ratio, window shading g-value, integrated solar radiation and gain utilization factor, which leads to threshold values significantly below the ones currently used. These revised requirements are more restrictive and, therefore, will act to improve a building's thermal performance during summer. As a rule of thumb applied for Portuguese climates, the reference gain utilization factor should assume a minimum value of 0.8 for a latitude angle range of 40-41oN, 0.6 for 38-39oN and 0.5 for 37oN. -- Highlights: → A newly revised methodology for Portuguese building thermal code. → The use of the gain utilization factor as an overheating risk index is suggested. → The proposed streamlined method depends on reference values. → Threshold maximum values are significantly below the ones currently used.

  5. Thermal performance study and evaluation of comfort temperatures in vernacular buildings of North-East India

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Manoj Kumar; Atreya, S.K. [Instrument Design and Development Centre, Indian Institute of Technology Delhi, New Delhi 110016 (India); Mahapatra, Sadhan [Department of Energy, Tezpur University, Tezpur 784028, Assam (India)

    2010-02-15

    Solar passive techniques are being used in vernacular buildings throughout the world. Researchers have done extensive study on thermal performance of vernacular buildings in the different parts of the world. Vernacular architecture of North-Eastern India represents the principle of climate-responsive architecture, which still lacks experimental validation and quantitative analysis. Thermal comfort not only makes the occupants comfortable but also governs energy consumption in the building. Detailed field studies on thermal performances of typical traditional vernacular dwellings in different bioclimatic zones have been undertaken. This field study includes detailed survey of 150 vernacular dwellings, field tests and thermal sensation vote of 300 occupants on ASHRAE thermal sensation scale. Field test includes measurement of temperature, humidity, illumination level and building design parameters. Thermal performances of these vernacular dwellings were evaluated for winter, pre-summer, summer/monsoon and pre-winter months of the year 2008. This evaluation is based on 'adaptive approach', which is the outcome of the field studies and is now part of ASHRAE standard 55/2004 for predicting comfortable temperature of naturally ventilated buildings. This study also tried to find out the range of comfort temperature in these vernacular buildings for different season of the year. It has been found that these vernacular dwellings perform quite satisfactorily except in the winter months and the occupants feel comfortable in a wider range of temperature. (author)

  6. Guidelines for Energy Simulation of Commercial Buildings: Final.

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, Michael; Caner, Phoebe

    1992-03-01

    This report distills the experience gained from intensive computer building simulation work for the Energy Edge project. The purpose of this report is twofold: to use that experience to guide conservation program managers in their use of modeling, and to improve the accuracy of design-phase computer models. Though the main emphasis of the report is on new commercial construction, it also addresses modeling as it pertains to retrofit construction. To achieve these purposes, this report will: (1) discuss the value of modeling for energy conservation programs; (2) discuss strengths and weaknesses of computer models; (3) provide specific guidelines for model input; (4) discuss input topics that are unusually large drivers of energy use and model inaccuracy; (5) provide guidelines for developing baseline models; (6) discuss types of energy conservation measures (ECMs) and building operation that are not suitable to modeling and present possible alternatives to modeling for analysis; and (7) provide basic requirements for model documentation. This project was initiated to determine whether commercial buildings can be designed and constructed to use at least 30% less energy than if they were designed and built to meet the current regional model energy code, the Model Conservation Standards (MCS) developed by the Pacific Northwest Electric Power and Conservation Planning Council. Secondary objectives of the project are to determine the incremental energy savings of a wide variety of ECMs and to compare the predictive accuracy of design-phase models with models that are carefully tuned to monitored building data.

  7. Effect of Thermal Bridges in Insulated Walls on Air-Conditioning Loads Using Whole Building Energy Analysis

    Directory of Open Access Journals (Sweden)

    Mohamed F. Zedan

    2016-06-01

    Full Text Available Thermal bridges in building walls are usually caused by mortar joints between insulated building blocks and by the presence of concrete columns and beams within the building envelope. These bridges create an easy path for heat transmission and therefore increase air-conditioning loads. In this study, the effects of mortar joints only on cooling and heating loads in a typical two-story villa in Riyadh are investigated using whole building energy analysis. All loads found in the villa, which broadly include ventilation, transmission, solar and internal loads, are considered with schedules based on local lifestyles. The thermal bridging effect of mortar joints is simulated by reducing wall thermal resistance by a percentage that depends on the bridges to wall area ratio (TB area ratio or Amj/Atot and the nominal thermal insulation thickness (Lins. These percentage reductions are obtained from a correlation developed by using a rigorous 2D dynamic model of heat transmission through walls with mortar joints. The reduction in thermal resistance is achieved through minor reductions in insulation thickness, thereby keeping the thermal mass of the wall essentially unchanged. Results indicate that yearly and monthly cooling loads increase almost linearly with the thermal bridge to wall area ratio. The increase in the villa’s yearly loads varies from about 3% for Amj/Atot = 0.02 to about 11% for Amj/Atot = 0.08. The monthly increase is not uniform over the year and reaches a maximum in August, where it ranges from 5% for Amj/Atot = 0.02 to 15% for Amj/Atot = 0.08. In winter, results show that yearly heating loads are generally very small compared to cooling loads and that heating is only needed in December, January and February, starting from late night to late morning. Monthly heating loads increase with the thermal bridge area ratio; however, the variation is not as linear as observed in cooling loads. The present results highlight the importance of

  8. Numerical simulation of thermal behavior during laser metal deposition shaping

    Institute of Scientific and Technical Information of China (English)

    LONG Ri-sheng; LIU Wei-jun; XING Fei; WANG Hua-bing

    2008-01-01

    Based on the element life and death theory of finite element analysis (FEA),a three-dimensional multi-track and multi-layer model for laser metal deposition shaping (LMDS) was developed with ANSYS parametric design language (APDL),and detailed numerical simulations of temperature and thermal stress were conducted.Among those simulations,long-edge parallel reciprocating scanning method was introduced.The distribution regularities of temperature,temperature gradient,Von Mise's effective stress,X-directional,Y-directional and Z-directional thermal stresses were studied.LMDS experiments were carried out with nickel-based superalloy using the same process parameters as those in simulation.The measured temperatures of molten pool are in accordance with the simulated results.The crack engendering and developing regularities of samples show good agreement with the simulation results.

  9. Building Simulation Modelers are we big-data ready?

    Energy Technology Data Exchange (ETDEWEB)

    Sanyal, Jibonananda [ORNL; New, Joshua Ryan [ORNL

    2014-01-01

    Recent advances in computing and sensor technologies have pushed the amount of data we collect or generate to limits previously unheard of. Sub-minute resolution data from dozens of channels is becoming increasingly common and is expected to increase with the prevalence of non-intrusive load monitoring. Experts are running larger building simulation experiments and are faced with an increasingly complex data set to analyze and derive meaningful insight. This paper focuses on the data management challenges that building modeling experts may face in data collected from a large array of sensors, or generated from running a large number of building energy/performance simulations. The paper highlights the technical difficulties that were encountered and overcome in order to run 3.5 million EnergyPlus simulations on supercomputers and generating over 200 TBs of simulation output. This extreme case involved development of technologies and insights that will be beneficial to modelers in the immediate future. The paper discusses different database technologies (including relational databases, columnar storage, and schema-less Hadoop) in order to contrast the advantages and disadvantages of employing each for storage of EnergyPlus output. Scalability, analysis requirements, and the adaptability of these database technologies are discussed. Additionally, unique attributes of EnergyPlus output are highlighted which make data-entry non-trivial for multiple simulations. Practical experience regarding cost-effective strategies for big-data storage is provided. The paper also discusses network performance issues when transferring large amounts of data across a network to different computing devices. Practical issues involving lag, bandwidth, and methods for synchronizing or transferring logical portions of the data are presented. A cornerstone of big-data is its use for analytics; data is useless unless information can be meaningfully derived from it. In addition to technical

  10. Thermal crosstalk simulation and measurement of linear terahertz detector arrays

    Science.gov (United States)

    Li, Weizhi; Huang, Zehua; Wang, Jun; Li, Mingyu; Gou, Jun; Jiang, Yadong

    2015-11-01

    Thermal simulation of differently structured linear terahertz detector arrays (TDAs) based on lithium tantalate was performed by finite element analysis (FEA). Simulation results revealed that a relatively simple TDA structure can have good thermal insulation, i.e., low thermal crosstalk effect (TCE), between adjacent pixels, which was thus selected for the real fabrication of TDA sample. Current responsivity (Ri) of the sample for a 2.52 THz source was measured to be 6.66 × 10-6 A/W and non-uniformity (NU) of Ri was 4.1%, showing good performance of the sample. TCE test result demonstrated that small TCE existed in the sample, which was in good agreement with the simulation results.

  11. Detailed thermal-hydraulic computation into a containment building

    Energy Technology Data Exchange (ETDEWEB)

    Caruso. A.; Flour, I.; Simonin, O. [EDF/LNH, Chatou (France); Cherbonnel, C [EDF/SEPTEN, Villeurbanne (France)

    1995-09-01

    This paper deals with numerical predictions of the influence of water sprays upon stratifications into a containment building using a two-dimensional two-phase flow code. Basic equations and closure assumptions are briefly presented. A test case in a situation involving spray evaporation is first detailed to illustrate the validation step. Then results are presented for a compressible recirculating flow into a containment building with condensation phenomena.

  12. Modelling to predict future energy performance of solar thermal cooling systems for building applications in the North East of England

    International Nuclear Information System (INIS)

    Controlling and reducing energy consumption in buildings has been identified by policy makers and politicians as way of meeting global targets for greenhouse gas reductions and mitigating the impacts of climate change. Buildings must be designed and built to withstand harsh future weather patterns, and be energy efficient to run. In the UK, there has been an increasing demand to provide cooling in summer months and this is likely to increase in the future with global temperatures rising. While the potential of solar thermal energy to cool buildings has been investigated in warmer climates, this is not the case in the UK. An optimised solar thermal simulation model was developed using the UKCIP climate change weather prediction scenarios over the next 40 years to assess cooling effectiveness delivered by solar powered air cooling systems. This paper bridges the modern concept of solar cooling technology and future potential for new build and retrofitted commercial applications, using modern modelling concepts. -- Highlights: • Weather scenarios in 2080 demonstrate greater demand of cooling. • Cooling absorption effectiveness on building types to increase in future years. • Application in cooler climates can still save considerable amounts of carbon

  13. Assessing energy and thermal comfort of different low-energy cooling concepts for non-residential buildings

    International Nuclear Information System (INIS)

    Highlights: • Impact of five cooling technologies are simulated in six European climate zones with Trnsys 17. • The ventilation strategies reduce the cooling energy need even in South Europe climate. • Constant ventilation controller can lead to a poor cooling performance. • Comparing radiant strategies with air conditioning scenario, the energy saving is predicted to within 5–35%. - Abstract: Energy consumption for cooling is growing dramatically. In the last years, electricity peak consumption grew significantly, switching from winter to summer in many EU countries. This is endangering the stability of electricity grids. This article outlines a comprehensive analysis of an office building performances in terms of energy consumption and thermal comfort (in accordance with static – ISO 7730:2005 – and adaptive thermal comfort criteria – EN 15251:2007 –) related to different cooling concepts in six different European climate zones. The work is based on a series of dynamic simulations carried out in the Trnsys 17 environment for a typical office building. The simulation study was accomplished for five cooling technologies: natural ventilation (NV), mechanical night ventilation (MV), fan-coils (FC), suspended ceiling panels (SCP), and concrete core conditioning (CCC) applied in Stockholm, Hamburg, Stuttgart, Milan, Rome, and Palermo. Under this premise, the authors propose a methodology for the evaluation of the cooling concepts taking into account both, thermal comfort and energy consumption

  14. Evaluating Different Green School Building Designs for Albania: Indoor Thermal Comfort, Energy Use Analysis with Solar Systems

    Science.gov (United States)

    Dalvi, Ambalika Rajendra

    Improving the conditions of schools in many parts of the world is gradually acquiring importance. The Green School movement is an integral part of this effort since it aims at improving indoor environmental conditions. This would in turn, enhance student- learning while minimizing adverse environmental impact through energy efficiency of comfort-related HVAC and lighting systems. This research, which is a part of a larger research project, aims at evaluating different school building designs in Albania in terms of energy use and indoor thermal comfort, and identify energy efficient options of existing schools. We start by identifying three different climate zones in Albania; Coastal (Durres), Hill/Pre-mountainous (Tirana), mountainous (Korca). Next, two prototypical school building designs are identified from the existing stock. Numerous scenarios are then identified for analysis which consists of combinations of climate zone, building type, building orientation, building upgrade levels, presence of renewable energy systems (solar photovoltaic and solar water heater). The existing building layouts, initially outlined in CAD software and then imported into a detailed building energy software program (eQuest) to perform annual simulations for all scenarios. The research also predicted indoor thermal comfort conditions of the various scenarios on the premise that windows could be opened to provide natural ventilation cooling when appropriate. This study also estimated the energy generated from solar photovoltaic systems and solar water heater systems when placed on the available roof area to determine the extent to which they are able to meet the required electric loads (plug and lights) and building heating loads respectively. The results showed that there is adequate indoor comfort without the need for mechanical cooling for the three climate zones, and that only heating is needed during the winter months.

  15. User's manual for computer code SOLTES-1 (simulator of large thermal energy systems)

    International Nuclear Information System (INIS)

    SOLTES simulates the steady-state response of thermal energy systems to time-varying data such as weather and loads. Thermal energy system models of both simple and complex systems can easily be modularly constructed from a library of routines. These routines mathematically model solar collectors, pumps, switches, thermal energy storage, thermal boilers, auxiliary boilers, heat exchangers, extraction turbines, extraction turbine/generators, condensers, regenerative heaters, air conditioners, heating and cooling of buildings, process vapor, etc.; SOLTES also allows user-supplied routines. The analyst need only specify fluid names to obtain readout of property data for heat-transfer fluids and constants that characterize power-cycle working fluids from a fluid property data bank. A load management capability allows SOLTES to simulate total energy systems that simultaneously follow heat and power loads and demands. Generalized energy accounting is available, and values for system performance parameters may be automatically determined by SOLTES. Because of its modularity and flexibility, SOLTES can be used to simulate a wide variety of thermal energy systems such as solar power/total energy, fossil fuel power plants/total energy, nuclear power plants/total energy, solar energy heating and cooling, geothermal energy, and solar hot water heaters

  16. Energy consumption program: A computer model simulating energy loads in buildings

    Science.gov (United States)

    Stoller, F. W.; Lansing, F. L.; Chai, V. W.; Higgins, S.

    1978-01-01

    The JPL energy consumption computer program developed as a useful tool in the on-going building modification studies in the DSN energy conservation project is described. The program simulates building heating and cooling loads and computes thermal and electric energy consumption and cost. The accuracy of computations are not sacrificed, however, since the results lie within + or - 10 percent margin compared to those read from energy meters. The program is carefully structured to reduce both user's time and running cost by asking minimum information from the user and reducing many internal time-consuming computational loops. Many unique features were added to handle two-level electronics control rooms not found in any other program.

  17. Building integrated solar thermal collectors for heating & cooling applications

    OpenAIRE

    Buker, Mahmut Sami

    2015-01-01

    International Energy Agency Solar Heating & Cooling (IEA SHC) programme states the fact that space/water heating and cooling demand account for over 75% of the energy consumed in single and multi-family homes. Solar energy technology can meet up to 100% of this demand depending on the size of the system, storage capacity, the heat load and the region’s climate. Solar thermal collectors are particular type of heat extracting devices that convert solar radiation into thermal energy through a...

  18. Thermal simulation and analysis of the STF cryomodule

    Institute of Scientific and Technical Information of China (English)

    XU Qing-Jin; Ohuchi Norihito; Kiyosumi Tsuchiya; Tsai Ming-Hsun; ZONG Zhan-Guo; ZHAI Ji-Yuan; GAO Jie

    2009-01-01

    STF is a superconducting RF test facility constructed at the high energy accelerator research orga-nization of Japan (KEK), as a main part of a R&D project for the proposed International Linear Collider (ILC) in Asia. Thermal study of the STF 1.3 GHz 9-cell cavity cryomodule was carried out within a collaboration between China and Japan. Static and dynamic thermal behaviors of the STF cryomodule were simulated and analyzed with the FEM method, and some simulation results were compared with the available experimental data. This paper presents the details.

  19. The Effect Of Thermal Insulation Of An Apartment Building On The Thermo-Hydraulic Stability Of Its Heating System

    Science.gov (United States)

    Kurčová, Mária

    2015-12-01

    The contribution aims to investigate the effect of the decreased thermal losses of an apartment building due to the thermal insulation of opaque external building constructions and the replacement of transparent constructions. It emphasizes the effect of the thermal characteristics of external constructions on the functionality of the existing heating system in the building and the related requirements for the renovation of the heating system in order to ensure the hydraulic stability of the system and the thermal comfort of the inhabitants.

  20. Selecting Eco-Friendly Thermal Systems for the “Vittoriale Degli Italiani” Historic Museum Building

    OpenAIRE

    Davide Astiaso Garcia; Umberto Di Matteo; Fabrizio Cumo

    2015-01-01

    Thermal systems installed in museums should guarantee the maintenance of the optimal hygrothermal parameters ranges for the conservation of their collection materials. Considering the preservation of historic buildings, according to their historical and landscaping constraints, not all the thermal system typologies could be installed in these buildings’ typologies. Therefore, the main aim of this paper is to present some indications for the choice of the best thermal system solutions for a co...

  1. Influence of duration of thermal comfort provision on heating behavior of buildings

    International Nuclear Information System (INIS)

    Because of the permanent dilemma whether residential buildings using district heating should be heated continually or discontinuously, we evaluated how the yearly heating load and the peak heating load of a small building in Serbia depend on the duration of thermal comfort provision. Using HTB2 software, a product of the Welsh School of Architecture, it was found that an increase in the duration of thermal comfort provision in the building from 16 h to 24 h increases the yearly heating load by 20%, reduces the peak heating load by up to 40% and may increase the number of new customers served with the same heating plant by up to 40%

  2. Electro-Thermal-Mechanical Simulation Capability Final Report

    Energy Technology Data Exchange (ETDEWEB)

    White, D

    2008-02-06

    This is the Final Report for LDRD 04-ERD-086, 'Electro-Thermal-Mechanical Simulation Capability'. The accomplishments are well documented in five peer-reviewed publications and six conference presentations and hence will not be detailed here. The purpose of this LDRD was to research and develop numerical algorithms for three-dimensional (3D) Electro-Thermal-Mechanical simulations. LLNL has long been a world leader in the area of computational mechanics, and recently several mechanics codes have become 'multiphysics' codes with the addition of fluid dynamics, heat transfer, and chemistry. However, these multiphysics codes do not incorporate the electromagnetics that is required for a coupled Electro-Thermal-Mechanical (ETM) simulation. There are numerous applications for an ETM simulation capability, such as explosively-driven magnetic flux compressors, electromagnetic launchers, inductive heating and mixing of metals, and MEMS. A robust ETM simulation capability will enable LLNL physicists and engineers to better support current DOE programs, and will prepare LLNL for some very exciting long-term DoD opportunities. We define a coupled Electro-Thermal-Mechanical (ETM) simulation as a simulation that solves, in a self-consistent manner, the equations of electromagnetics (primarily statics and diffusion), heat transfer (primarily conduction), and non-linear mechanics (elastic-plastic deformation, and contact with friction). There is no existing parallel 3D code for simulating ETM systems at LLNL or elsewhere. While there are numerous magnetohydrodynamic codes, these codes are designed for astrophysics, magnetic fusion energy, laser-plasma interaction, etc. and do not attempt to accurately model electromagnetically driven solid mechanics. This project responds to the Engineering R&D Focus Areas of Simulation and Energy Manipulation, and addresses the specific problem of Electro-Thermal-Mechanical simulation for design and analysis of energy

  3. Improving the thermal performance of the building envelopes with the use of foam glass-ceramics

    Directory of Open Access Journals (Sweden)

    D.G. Portnyagin

    2015-12-01

    Full Text Available Recommendations on eliminating the defects of thermal insulation on the basis of the previously carried out thermal imaging surveys were given. Constructive solutions of building envelopes were proposed with regard to modeling thermal fields in ELCUT. A typical solution of thermal insulation of the basement joint is the unit exterior insulation of the basement wall to the level of the facing course bottom. This constructive solution is characterized by a significant thermal bridge, in the direction through the cross-section of the floor slab under the insulation of the wall. The article presents the results of eliminating the thermal bridge by substituting of ceramic or silica bricks for thermal insulation bricks of foamglass. We discussed the roof and parapet joint. The paper also presents the results of heat loss calculation when replacing of the top line of backfills above the level of the coating by the brick thermal insulation made of foamglass.

  4. Review of thermal energy storage technologies based on PCM application in buildings

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Zhang, Yinping

    2013-01-01

    developed to serve the building industry. Various PCM technologies tailored for building applications are studied with respect to technological potential to improve indoor environment, increase thermal inertia and decrease energy use for building operation. What is more, in this review special attention......Thermal energy storage systems (TES), using phase change material (PCM) in buildings, are widely investigated technologies and a fast developing research area. Therefore, there is a need for regular and consistent reviews of the published studies. This review is focused on PCM technologies...... is paid to discussion and identification of proper methods to correctly determine the thermal properties of PCM materials and their composites and as well procedures to determine their energy storage and saving potential. The purpose of the paper is to highlight promising technologies for PCM application...

  5. Mathematical and Statistical Models and Methods for Describing the Thermal Characteristics of Buildings

    DEFF Research Database (Denmark)

    Madsen, Henrik; Bacher, Peder; Andersen, Philip Hvidthøft Delff

    2010-01-01

    the thermal characteristics of buildings. Many of the stochastic models are developed and tested using data from outdoor test- ing during a number of EU projects (PASSYS, PASLINK, DAME-BC, ..). These projects have provided the background for new methods for using frequent readings of the energy consumption...... methods for time series modelling or system identification. Applying these methods the following can be achieved: Characterization of the energy performance of buildings (including energy labelling), identification of how to improve the thermal performance of the building, and improved control of the energy......This paper describes a number of statistical methods and models for describing the thermal characteristics of buildings using frequent readings of heat consumption, ambient air temperature, and other available climate variables. For some of the methods frequent readings of the indoor air...

  6. Nuclear Thermal Rocket Element Environmental Simulator (NTREES) Upgrade Activities

    Science.gov (United States)

    Emrich, William J., Jr.

    2014-01-01

    Over the past year the Nuclear Thermal Rocket Element Environmental Simulator (NTREES) has been undergoing a significant upgrade beyond its initial configuration. The NTREES facility is designed to perform realistic non-nuclear testing of nuclear thermal rocket (NTR) fuel elements and fuel materials. Although the NTREES facility cannot mimic the neutron and gamma environment of an operating NTR, it can simulate the thermal hydraulic environment within an NTR fuel element to provide critical information on material performance and compatibility. The first phase of the upgrade activities which was completed in 2012 in part consisted of an extensive modification to the hydrogen system to permit computer controlled operations outside the building through the use of pneumatically operated variable position valves. This setup also allows the hydrogen flow rate to be increased to over 200 g/sec and reduced the operation complexity of the system. The second stage of modifications to NTREES which has just been completed expands the capabilities of the facility significantly. In particular, the previous 50 kW induction power supply has been replaced with a 1.2 MW unit which should allow more prototypical fuel element temperatures to be reached. The water cooling system was also upgraded to so as to be capable of removing 100% of the heat generated during. This new setup required that the NTREES vessel be raised onto a platform along with most of its associated gas and vent lines. In this arrangement, the induction heater and water systems are now located underneath the platform. In this new configuration, the 1.2 MW NTREES induction heater will be capable of testing fuel elements and fuel materials in flowing hydrogen at pressures up to 1000 psi at temperatures up to and beyond 3000 K and at near-prototypic reactor channel power densities. NTREES is also capable of testing potential fuel elements with a variety of propellants, including hydrogen with additives to inhibit

  7. Dynamic Heat Storage and Cooling Capacity of a Concrete Deck with PCM and Thermally Activated Building System

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    the performance of the new deck with PCM concrete is the thermal properties of such a new material, as the PCM concrete is yet to be well defined. The results presented in the paper include models in which the PCM concrete material properties, such as thermal conductivity, and specific heat capacity were first......This paper presents a heat storage and cooling concept that utilizes a phase change material (PCM) and a thermally activated building system (TABS) implemented in a hollow core concrete deck. Numerical calculations of the dynamic heat storage capacity of the hollow core concrete deck element...... with and without microencapsulated PCM are presented. The new concrete deck with microencapsulated PCM is the standard deck on which an additional layer of the PCM concrete was added and, at the same time, the latent heat storage was introduced to the construction. The challenge of numerically simulating...

  8. Building energy efficiency and thermal comfort in tropical climates

    Energy Technology Data Exchange (ETDEWEB)

    Bastide, A.; Lauret, P.; Garde, F.; Boyer, H. [Laboratoire de Physique du Batiment et des Systemes, Universite de La Reunion, Saint-Pierre, Ile de La Reunion (France)

    2006-07-01

    The paper deals with the optimization of building energy efficiency in tropical climates by reducing the period of air-conditioning thanks to natural ventilation and a better bioclimatic design. A bioclimatic approach to designing comfortable buildings in hot and humid tropical regions requires, firstly, some preliminary, important work on the building envelope to limit the energy contributions, and secondly, an airflow optimization based on the analysis of natural ventilation airflow networks. For the first step, tools such as nodal or zonal models have been largely implemented in building energy codes to evaluate energy transport between indoor and outdoor. For the second step, the assessment of air velocities, in three dimensions and in a large space, can only be performed through the use of detailed models such as with CFD. A new modelling approach based on the derivation of a new quantity - i.e. the well-ventilated percentage of a living space is proposed. The well-ventilated percentage of a space allows a time analysis of the air motion behaviour of the building in its environment. These percentages can be over a period such as 1 day, a season or a year. Twelve living spaces with different configuration of openings have been studied to compare the performance of ventilation function of the opening distribution. Results and discussion are presented in the paper. This method is helpful for an architect to design the rooms according to their use, and their environment. Finally, the developed models can be used in building projects to estimate the period of the natural ventilation and to reduce the energy consumption due to air-conditioning. (author)

  9. Dynamic evaluation of thermal comfort environment of air-conditioned buildings

    Energy Technology Data Exchange (ETDEWEB)

    Hanqing, Wang; Zhiyong, Wang [Department of Civil Engineering, Zhuzhou Institute of Technology, Zhuzhou Hunan 412008 (China); Chunhua, Huang; Yingyun, Liu [Nanhua University, Hengyang 421001 (China); Zhiqiang, Liu [School of Energy and Power Engineering, Central South University, Changsha 410083 (China); Guangfa, Tang [School of Civil Engineering, Hunan University, Changsha 410082 (China)

    2006-11-15

    In this paper, based upon Fanger's thermal comfort concept, several concepts, which utilize computing results obtained from the large eddy simulation (LES), are put forward, such as thermal comfort index based on time-averaged parameters, instantaneous thermal index, time-averaged thermal comfort index and time-averaged thermal comfort index along walking routes. Also their discrepancies and calculation methods are discussed in the paper. Apart from these, we have calculated PD value as an example, whose results indicate that the distributions of four indices are obviously different. Therefore, it is suggested to distinguish different cases and select correspondingly thermal comfort evaluation indices.

  10. Detailed user behavior in building simulation; Gedetailleerd gebruikersgedrag in gebouwsimulatie

    Energy Technology Data Exchange (ETDEWEB)

    Parys, W.; Saelens, D.; Hens, H. [Afdeling Bouwfysica, K.U. Leuven, Leuven (Belgium)

    2011-02-15

    A global methodology to integrate realistic use of an office building in uncertainty analysis of the energy consumption through a modular and stochastic behavioral model is proposed. The latter incorporates both the stochastic nature of occupant behavior and the inherent variability amongst individuals by defining representative active and passive users. The behavioral model consists of submodels for occupancy, use of shading devices, window operation, control of artificial lighting and heat gains by appliances. The submodels are selected based on a literature review. This methodology is applied in a Monte Carlo analysis of the uncertainty because of the building use on the simulated energy demands of an office building. [Dutch] Er is een globale methode ontwikkeld om realistisch gebouwgebruik in een kantoorgebouw te integreren in een onzekerheidsanalyse voor het energiegebruik. Dit gebeurt via een modulair en stochastisch gedragsmodel. Het gedragsmodel bestaat uit submodellen voor bezetting, gebruik van zonwering, openen van het raam, sturing van het kunstlicht en warmteproductie door kantoorapparatuur. Alle submodellen zijn geselecteerd op basis van een literatuurstudie. Deze methode wordt toegepast in een Monte Carlo-analyse van de onzekerheid door gebouwgebruik op gesimuleerde energiebehoeften van een kantoorgebouw.

  11. Energy Simulation of a Holographic PVT Concentrating System for Building Integration Applications

    Directory of Open Access Journals (Sweden)

    Julia Marín-Sáez

    2016-07-01

    Full Text Available A building integrated holographic concentrating photovoltaic-thermal system has been optically and energetically simulated. The system has been designed to be superimposed into a solar shading louvre; in this way the concentrating unit takes profit of the solar altitude tracking, which the shading blinds already have, to increase system performance. A dynamic energy simulation has been conducted in two different locations—Sde Boker (Israel and Avignon (France—both with adequate annual irradiances for solar applications, but with different weather and energy demand characteristics. The simulation engine utilized has been TRNSYS, coupled with MATLAB (where the ray-tracing algorithm to simulate the holographic optical performance has been implemented. The concentrator achieves annual mean optical efficiencies of 30.3% for Sde Boker and 43.0% for the case of Avignon. Regarding the energy production, in both locations the thermal energy produced meets almost 100% of the domestic hot water demand as this has been considered a priority in the system control. On the other hand, the space heating demands are covered by a percentage ranging from 15% (Avignon to 20% (Sde Boker. Finally, the electricity produced in both places covers 7.4% of the electrical demand profile for Sde Boker and 9.1% for Avignon.

  12. How to measure thermal effects of personal cooling systems: human, thermal manikin and human simulator study

    International Nuclear Information System (INIS)

    Thermal effects, such as cooling power and thermophysiological responses initiated upon application of a personal cooling system, can be assessed with (i) humans, (ii) a thermal manikin and (iii) a thermophysiological human simulator. In order to compare these methods, a cooling shirt (mild cooling) and an ice vest (strong cooling) were measured using human participants and a thermal manikin. Under all conditions, cooling was provided for 45 min, while resting at a room temperature of 24.6–25.0 °C and a relative humidity of 22–24%. Subsequently, the thermophysiological human simulator was used under the same conditions to provide data on thermophysiological responses such as skin and rectal temperatures. The cooling power determined using the thermal manikin was 2 times higher for the cooling shirt and 1.5 times higher for the ice vest compared to the cooling power determined using human participants. For the thermophysiological human simulator, the cooling power of the cooling shirt was similar to that obtained using human participants. However, it was 2 times lower for the ice vest when using the thermophysiological human simulator. The thermophysiological human simulator is shown to be a useful tool to predict thermophysiological responses, especially upon application of mild cooling intensity. However, the thermophysiological human simulator needs to be further improved for strong cooling intensities under heterogeneous conditions

  13. A New Mathematical Simulation Approach for Thermal Cracking Furnace Studies

    Institute of Scientific and Technical Information of China (English)

    LanXingying; XuChunming; GaoJinsen; ZhangHongmei

    2005-01-01

    Thermal cracking of hydrocarbons for olefin production is normally carried out in long reactor tubes suspended in a large gas fired furnace. In this paper, a coupled furnace-reactor mathematical model based on a computational fluid dynamics (CFD) technique is developed to simulate the complex fluid dynamics phenomena in the thermal cracking furnace. The model includes mass transfer, momentum transfer, and heat transfer, as well as thermal cracking reactions, fuel combustion and radiative heat transfer. The rationality and reliability of the mathematical model is confirmed by the approximate agreement of predicted data and industrial data. The coupled furnace-reactor simulation revealed the details of both the transfer and reaction processes taking place in the thermal cracking furnace. The results indicate highly nonuniform distribution of the flue-gas velocity, concentration and temperature in the furnace, which cause nonuniform distribution of tube skin temperature and heat flux of the reactor tubes. Profiles of oil-gas velocity,pressure, temperature and product yields in the lengthwise direction of the reactor tube are obtained. Furthermore, in the radial direction steep velocity and temperature gradients and relatively slight gradients of species concentration are found.In conclusion, the model can provide more information on the fluid dynamics and reaction behavior in the thermal cracking furnace, and guidance for the design and improvement of thermal cracking furnaces.

  14. Simulations of thermal conductance across tilt grain boundaries in graphene

    Institute of Scientific and Technical Information of China (English)

    Peng Wang; Bo Gong; Qiong Feng; Hong-Tao Wang

    2012-01-01

    Non-equilibrium molecular dynamics (MD) method was performed to simulate the thermal transportation process in graphene nanoribbons (GNRs).A convenient way was conceived to introduce tilt grain boundaries (GBs) into the graphene lattice by repetitive removing C atom rows along certain directions.Comprehensive MD simulations reveal that larger-angle GBs are effective thermal barriers and substantially reduce the average thermal conductivity of GNRs.The GB thermal conductivity is ~ 10 W.m-1·K-1 for a bicrystal GNR with a misorientation of 21.8°,which is ~97% less than that of a prefect GNR with the same size.The total thermal resistance has a monotonic dependence on the density of the 5-7 defects along the GBs.A theoretical model is proposed to capture this relation and resolve the contributions by both the reduction in the phonon mean free path and the defect-induced thermal resistance.

  15. Building intelligence in third-generation training and battle simulations

    Science.gov (United States)

    Jacobi, Dennis; Anderson, Don; von Borries, Vance; Elmaghraby, Adel; Kantardzic, Mehmed; Ragade, Rammohan

    2003-09-01

    Current war games and simulations are primarily attrition based, and are centered on the concept of force on force. They constitute what can be defined as "second generation" war games. So-called "first generation" war games were focused on strategy with the primary concept of mind on mind. We envision "third generation" war games and battle simulations as concentrating on effects with the primary concept being system on system. Thus the third generation systems will incorporate each successive generation and take into account strategy, attrition and effects. This paper will describe the principal advantages and features that need to be implemented to create a true "third generation" battle simulation and the architectural issues faced when designing and building such a system. Areas of primary concern are doctrine, command and control, allied and coalition warfare, and cascading effects. Effectively addressing the interactive effects of these issues is of critical importance. In order to provide an adaptable and modular system that will accept future modifications and additions with relative ease, we are researching the use of a distributed Multi-Agent System (MAS) that incorporates various artificial intelligence methods. The agent architecture can mirror the military command structure from both vertical and horizontal perspectives while providing the ability to make modifications to doctrine, command structures, inter-command communications, as well as model the results of various effects upon one another, and upon the components of the simulation. This is commonly referred to as "cascading effects," in which A affects B, B affects C and so on. Agents can be used to simulate units or parts of units that interact to form the whole. Even individuals can eventually be simulated to take into account the affect to key individuals such as commanders, heroes, and aces. Each agent will have a learning component built in to provide "individual intelligence" based on

  16. Thermal comfort and ventilation criteria for low energy residential buildings in building codes

    DEFF Research Database (Denmark)

    Cao, Guangyu; Kurnitski, Jarek; Awbi, Hazim;

    2012-01-01

    Indoor environmental quality and energy performance of buildings are becoming more and more important in the design and construction of low energy, passive and zero energy buildings. At the same time, improved insulation and air tightness have the potential to resulting in a deterioration of the ...

  17. Weldability investigation steel P 91 by weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2015-07-01

    Full Text Available This paper elaborates results of hardness and impact energy of thermal cycle simulated specimens of high-alloy steel P 91 and their dependence on cooling time from 800 to 500 °C. Results were obtained by measuring hardness HV 1 and by experimental testing of Charpy notched specimens. Metallographic analysis of samples was performed on scanning electronic microscope.

  18. Optical and thermal simulation chain for LED package

    NARCIS (Netherlands)

    Tapaninen, O.; Myohanen, P.; Majanen, M.; Sitomaniemi, A.; Olkkonen, J.; Hildenbrand, V.; Gielen, A.W.J.; Mackenzie, F.V.; Barink, M.; Smilauer, V.; Patzak, B.

    2016-01-01

    This paper presents a test case for coupling two physical aspects of an LED, optical and thermal, using specific simulation models coupled through an open source platform for distributed multi-physics modelling. The glue code for coupling is written with Python programming language including routine

  19. Thermal stability of silicon nanowires:atomistic simulation study

    Institute of Scientific and Technical Information of China (English)

    Liu Wen-Liang; Zhang Kai-Wang; Zhong Jian-Xin

    2009-01-01

    Using the Stillinger-Weber (SW) potential model, we investigate the thermal stability of pristine silicon nanowires based on classical molecular dynamics (MD) simulations. We explore the structural evolutions and the Lindemann indices of silicon nanowires at different temperatures in order to unveil atomic-level melting behaviour of silicon nanowires.The simulation results show that silicon nanowires with surface reconstructions have higher thermal stability than those without surface reconstructions, and that silicon nanowires with perpendicular dimmer rows on the two (100) surfaces have somewhat higher thermal stability than nanowires with parallel dimmer rows on the two (100) surfaces. Furthermore, the melting temperature of silicon nanowires increases as their diameter increases and reaches a saturation value close to the melting temperature of bulk silicon. The value of the Lindemann index for melting silicon nanowires is 0.037.

  20. Hybrid simulation of metal oxide surge-arrester thermal behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Huang, L.; Raghuveer, M.R. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Electrical and Computer Engineering

    1996-01-01

    A finite-difference-based technique for simulating the thermal behaviour of a metal oxide surge arrester (MOSA) was described. The improved hybrid thermal modelling technique was claimed to accurately represent heat-transfer modes. Fin theory was used to represent arrester sheds. The proposed model, which relies on simple measurements at the arrester terminals, yields the temporal variation of temperature in a MOSA in both the axial and radial direction. The thermal behaviour of a MOSA under steady-state and transient conditions can be simulated using such a model under different environmental conditions. The accuracy of the modelling technique was demonstrated experimentally by measurements conducted on an arrester. 15 refs., 7 figs.

  1. Infrared Thermography Assessment of Thermal Bridges in Building Envelope: Experimental Validation in a Test Room Setup

    Directory of Open Access Journals (Sweden)

    Francesco Bianchi

    2014-10-01

    Full Text Available Thermal infrared imaging is a valuable tool to perform non-destructive qualitative tests and to investigate buildings envelope thermal-energy behavior. The assessment of envelope thermal insulation, ventilation, air leakages, and HVAC performance can be implemented through the analysis of each thermogram corresponding to an object surface temperature. Thermography also allows the identification of thermal bridges in buildings’ envelope that, together with windows and doors, constitute one of the weakest component increasing thermal losses. A quantitative methodology was proposed in previous researches by the authors in order to evaluate the effect of such weak point on the energy balance of the whole building. In the present work, in-field experimental measurements were carried out with the purpose of evaluating the energy losses through the envelope of a test room experimental field. In-situ thermal transmittance of walls, ceiling and roof were continuously monitored and each element was characterized by its own thermal insulation capability. Infrared thermography and the proposed quantitative methodology were applied to assess the energy losses due to thermal bridges. The main results show that the procedure confirms to be a reliable tool to quantify the incidence of thermal bridges in the envelope thermal losses.

  2. A Method for more specific Simulation of Operative Temperature in Thermal Analysis Programmes

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik

    2008-01-01

    Simulation of energy consumption of buildings on hourly basis is closely connected to the thermal indoor climate. The operative temperature can be used as a simple measure for thermal environment. The operative temperature is a function of the air temperature, the mean radiant temperature...... and inhomogeneous radiation plays an important role for the usability and functionality of the room. In order to calculate the mean radiant temperature as function of the person´s location in the room one needs to calculate the angular factor between the person and the surfaces. The angular factor between surfaces...... can easily be calculated; however the angular factor between a person and a surface cannot be found directly from a formula, but needs to be approximated in order to be used in computer simulations. The paper describes different kinds of validations that have been done to compare different models...

  3. Preparation and characterization of phase change material for thermal energy storage in buildings

    Science.gov (United States)

    Lo, Tommy Y.

    2016-04-01

    The paper presents the developing of novel form-stable composite phase change material (PCM) by incorporation of paraffin into lightweight aggregate through vacuum impregnation. The macro-encapsulated Paraffin-lightweight aggregate is a chemical compatible, thermal stable and thermal reliable PCM material for thermal energy storage applications in buildings. The 28 days compressive strength of NWAC using PCM-LWA is 33 - 53 MPa, which has an opportunity for structural purpose. Scanning electronic microscopic images indicated the paraffin can be held inside the porous structure of the aggregate. Thermal performance test showed that the cement paste panel with composite PCM can reduce the indoor temperature.

  4. Predictive Optimal Control of Active and Passive Building Thermal Storage Inventory

    Energy Technology Data Exchange (ETDEWEB)

    Gregor P. Henze; Moncef Krarti

    2003-12-17

    Cooling of commercial buildings contributes significantly to the peak demand placed on an electrical utility grid. Time-of-use electricity rates encourage shifting of electrical loads to off-peak periods at night and weekends. Buildings can respond to these pricing signals by shifting cooling-related thermal loads either by precooling the building's massive structure or the use of active thermal energy storage systems such as ice storage. While these two thermal batteries have been engaged separately in the past, this project investigates the merits of harnessing both storage media concurrently in the context of predictive optimal control. This topical report describes the demonstration of the model-based predictive optimal control for active and passive building thermal storage inventory in a test facility in real-time using time-of-use differentiated electricity prices without demand charges. The laboratory testing findings presented in this topical report cover the second of three project phases. The novel supervisory controller successfully executed a three-step procedure consisting of (1) short-term weather prediction, (2) optimization of control strategy over the next planning horizon using a calibrated building model, and (3) post-processing of the optimal strategy to yield a control command for the current time step that can be executed in the test facility. The primary and secondary building mechanical systems were effectively orchestrated by the model-based predictive optimal controller in real-time while observing comfort and operational constraints. The findings reveal that when the optimal controller is given imperfect weather fore-casts and when the building model used for planning control strategies does not match the actual building perfectly, measured utility costs savings relative to conventional building operation can be substantial. This requires that the facility under control lends itself to passive storage utilization and the building

  5. Introducing molecular life science students to model building using computer simulations

    NARCIS (Netherlands)

    Aegerter-Wilmsen, T.; Janssen, F.J.J.M.; Kettenis, D.; Sessink, O.; Hartog, R.; Bisseling, T.

    2006-01-01

    Computer simulations can facilitate the building of models of natural phenomena in research, for example in the molecular life sciences. In order to introduce molecular life science students to using computer simulations for model building, a digital case was developed in which students build a mode

  6. Combining Infrared Thermography and Numerical Analysis for Evaluating Thermal Bridges In Buildings: A Case Study

    Directory of Open Access Journals (Sweden)

    Iole Nardi

    2015-01-01

    Full Text Available Energy dispersions for transmission in buildings with highly insulated envelope are mainly due to thermal bridges. And because the energy certification of buildings shall be based on real thermal performance and not on theoretical components, nowadays their incidence on energy saving is relevant. Currently, infrared thermography is considered exclusively as a qualitative tool to detect thermal irregularities in buildings, but thermographic inspection allows not only the localization of thermal bridges, but also the identification of temperature field and, therefore, the quantization of the energy losses through such elements of discontinuities. This approach marks a shift from a qualitative to a quantitative analysis of the thermographic image of a building. The aim of this paper is to study the effect of three different types of thermal bridge, estimated as a percentage increase of the homogeneous wall thermal transmittance. Results are obtained exclusively with thermographic surveys without further information on the wall stratigraphy. Finally, the methodology has been validated by comparing with the results obtained by numerical calculation.

  7. Engineering-Based Thermal CFD Simulations on Massive Parallel Systems

    KAUST Repository

    Frisch, Jérôme

    2015-05-22

    The development of parallel Computational Fluid Dynamics (CFD) codes is a challenging task that entails efficient parallelization concepts and strategies in order to achieve good scalability values when running those codes on modern supercomputers with several thousands to millions of cores. In this paper, we present a hierarchical data structure for massive parallel computations that supports the coupling of a Navier–Stokes-based fluid flow code with the Boussinesq approximation in order to address complex thermal scenarios for energy-related assessments. The newly designed data structure is specifically designed with the idea of interactive data exploration and visualization during runtime of the simulation code; a major shortcoming of traditional high-performance computing (HPC) simulation codes. We further show and discuss speed-up values obtained on one of Germany’s top-ranked supercomputers with up to 140,000 processes and present simulation results for different engineering-based thermal problems.

  8. Engineering-Based Thermal CFD Simulations on Massive Parallel Systems

    Directory of Open Access Journals (Sweden)

    Jérôme Frisch

    2015-05-01

    Full Text Available The development of parallel Computational Fluid Dynamics (CFD codes is a challenging task that entails efficient parallelization concepts and strategies in order to achieve good scalability values when running those codes on modern supercomputers with several thousands to millions of cores. In this paper, we present a hierarchical data structure for massive parallel computations that supports the coupling of a Navier–Stokes-based fluid flow code with the Boussinesq approximation in order to address complex thermal scenarios for energy-related assessments. The newly designed data structure is specifically designed with the idea of interactive data exploration and visualization during runtime of the simulation code; a major shortcoming of traditional high-performance computing (HPC simulation codes. We further show and discuss speed-up values obtained on one of Germany’s top-ranked supercomputers with up to 140,000 processes and present simulation results for different engineering-based thermal problems.

  9. Calculation of the thermal solar contribution in facilities of ACS in buildings. Comparison between the method of strong simulation and F-Chart considering lost in the circuits; Calculo de la contribucion solar termica en instalaciones de ACS en edificios. Comparacion entre el metodo de simulacion dinamica y F-Chart considerando perdidas en los circuitos

    Energy Technology Data Exchange (ETDEWEB)

    Guillo, J. F.; Lucas, M.; Lucas, R.; Vicente, P. G.

    2008-07-01

    It has analyzed the impact of distribution losses in the size of solar installations by comparing two methods commonly used in calculating the contribution of solar residential building: f-chart and dynamic simulation. 3 schemes have been analysed in a building 22 houses and 70 occupants located in the IV and climate in the province of Alicante. For comparison between the two methodologies have been used for calculating the same values input from climate data as consumption of ACS. (Author)

  10. Building Merger Trees from Cosmological N-body Simulations

    CERN Document Server

    Tweed, D; Blaizot, J; Colombi, S; Slyz, A

    2009-01-01

    Although a fair amount of work has been devoted to growing Monte-Carlo merger trees which resemble those built from an N-body simulation, comparatively little effort has been invested in quantifying the caveats one necessarily encounters when one extracts trees directly from such a simulation. To somewhat revert the tide, this paper seeks to provide its reader with a comprehensive study of the problems one faces when following this route. The first step to building merger histories of dark matter haloes and their subhaloes is to identify these structures in each of the time outputs (snapshots) produced by the simulation. Even though we discuss a particular implementation of such an algorithm (called AdaptaHOP) in this paper, we believe that our results do not depend on the exact details of the implementation but extend to most if not all (sub)structure finders. To illustrate this point, we compare AdaptaHOP s results to the standard Friend- Of-Friend algorithm (FOF), widely utilized in the astrophysical commu...

  11. An algorithm to build mock galaxy catalogues using MICE simulations

    CERN Document Server

    Carretero, J; Gaztanaga, E; Crocce, M; Fosalba, P

    2014-01-01

    We present a method to build mock galaxy catalogues starting from a halo catalogue that uses halo occupation distribution (HOD) recipes as well as the subhalo abundance matching (SHAM) technique. Combining both prescriptions we are able to push the absolute magnitude of the resulting catalogue to fainter luminosities than using just the SHAM technique and can interpret our results in terms of the HOD modelling. We optimize the method by populating with galaxies friends-of-friends dark matter haloes extracted from the Marenostrum Institut de Ci\\`{e}ncies de l'Espai (MICE) dark matter simulations and comparing them to observational constraints. Our resulting mock galaxy catalogues manage to reproduce the observed local galaxy luminosity function and the colour-magnitude distribution as observed by the Sloan Digital Sky Survey. They also reproduce the observed galaxy clustering properties as a function of luminosity and colour. In order to achieve that, the algorithm also includes scatter in the halo mass - gala...

  12. Simulation Technology Laboratory Building 970 hazards assessment document

    International Nuclear Information System (INIS)

    The Department of Energy Order 5500.3A requires facility-specific hazards assessments be prepared, maintained, and used for emergency planning purposes. This hazards assessment document describes the chemical and radiological hazards associated with the Simulation Technology Laboratory, Building 970. The entire inventory was screened according to the potential airborne impact to onsite and offsite individuals. The air dispersion model, ALOHA, estimated pollutant concentrations downwind from the source of a release, taking into consideration the toxicological and physical characteristics of the release site, the atmospheric conditions, and the circumstances of the release. The greatest distances at which a postulated facility event will produce consequences exceeding the ERPG-2 and Early Severe Health Effects thresholds are 78 and 46 meters, respectively. The highest emergency classification is a Site Area Emergency. The Emergency Planning Zone is 100 meters

  13. Simulation Technology Laboratory Building 970 hazards assessment document

    Energy Technology Data Exchange (ETDEWEB)

    Wood, C.L.; Starr, M.D.

    1994-11-01

    The Department of Energy Order 5500.3A requires facility-specific hazards assessments be prepared, maintained, and used for emergency planning purposes. This hazards assessment document describes the chemical and radiological hazards associated with the Simulation Technology Laboratory, Building 970. The entire inventory was screened according to the potential airborne impact to onsite and offsite individuals. The air dispersion model, ALOHA, estimated pollutant concentrations downwind from the source of a release, taking into consideration the toxicological and physical characteristics of the release site, the atmospheric conditions, and the circumstances of the release. The greatest distances at which a postulated facility event will produce consequences exceeding the ERPG-2 and Early Severe Health Effects thresholds are 78 and 46 meters, respectively. The highest emergency classification is a Site Area Emergency. The Emergency Planning Zone is 100 meters.

  14. Analysis of the effect of passive strategies on a nearly zero Danish residential building by means of dynamic simulations

    DEFF Research Database (Denmark)

    Avantaggiato, Marta; Simone, Angela; de Carli, Michele;

    2014-01-01

    is raising the issue of overheating even in the middle seasons creating not negligible thermal discomfort. Through building simulation program, the effect of passive cooling strategies, such as solar shading and natural night-time ventilation, on a residential building under Copenhagen climate conditions...... on the indoor environment. When an alternative mechanical ventilation system was considered to exploit the nighttime cooling potential,results show a more constant indoor air temperature performance, just below 26˚C. Even though this temperature trend satisfied the design conditions and users’ safety,it isn...

  15. The updated algorithm of the Energy Consumption Program (ECP): A computer model simulating heating and cooling energy loads in buildings

    Science.gov (United States)

    Lansing, F. L.; Strain, D. M.; Chai, V. W.; Higgins, S.

    1979-01-01

    The energy Comsumption Computer Program was developed to simulate building heating and cooling loads and compute thermal and electric energy consumption and cost. This article reports on the new additional algorithms and modifications made in an effort to widen the areas of application. The program structure was rewritten accordingly to refine and advance the building model and to further reduce the processing time and cost. The program is noted for its very low cost and ease of use compared to other available codes. The accuracy of computations is not sacrificed however, since the results are expected to lie within + or - 10% of actual energy meter readings.

  16. Simulating past droughts and associated building damages in France

    Directory of Open Access Journals (Sweden)

    T. Corti

    2009-09-01

    Full Text Available Droughts can induce important building damages due to shrinking and swelling of soils, leading to costs as large as for floods in some regions. Previous studies have focused on damage data analysis, geological or constructional aspects. Here, a study investigating the climatic aspects of soil subsidence damage is presented for the first time. We develop a simple model to examine if the meteorology has a considerable impact on the interannual variability of damages from soil subsidence in France. We find that the model is capable of reproducing yearly drought-induced building damages for the time period 1989–2002, thus suggesting a strong meteorological influence. Furthermore, our results reveal a doubling of damages in these years compared to 1961–1990, mainly as a consequence of increasing temperatures. This indicates a link to climate change. We also apply the model to the extreme summer of 2003, which caused a further increase in damage by a factor four, according to a preliminary damage estimate. The simulation result for that year shows strong damage underestimation, pointing to additional sources of vulnerability. Damage data suggest a higher sensitivity to soil subsidence of regions first affected by drought in the 2003 summer, possibly due to a lack of preparedness and adaptation. This is of strong concern in the context of climate change, as densely populated regions in Central Europe and North America are expected to become newly affected by drought in the future.

  17. Investigation of thermal effect on exterior wall surface of building material at urban city area

    Directory of Open Access Journals (Sweden)

    Mohd Fadhil Md Din, Hazlini Dzinun, M. Ponraj, Shreeshivadasan Chelliapan, Zainura Zainun Noor, Dilshah Remaz, Kenzo Iwao

    2012-01-01

    Full Text Available This paper describes the investigation of heat impact on the vertical surfaces of buildings based on their thermal behavior. The study was performed based on four building materials that is commonly used in Malaysia; brick, concrete, granite and white concrete tiles. The thermal performances on the building materials were investigated using a surface temperature sensor, data logging system and infrared thermography. Results showed that the brick had the capability to absorb and store heat greater than other materials during the investigation period. The normalized heat (total heat/solar radiation of the brick was 0.093 and produces high heat (51% compared to granite, confirming a substantial amount of heat being released into the atmosphere through radiation and convection. The most sensitive material that absorbs and stores heat was in the following order: brick > concrete > granite > white concrete tiles. It was concluded that the type of exterior wall material used in buildings had significant impact to the environment.

  18. Investigation of thermal effect on exterior wall surface of building material at urban city area

    Energy Technology Data Exchange (ETDEWEB)

    Md Din, Mohd Fadhil; Dzinun, Hazlini; Ponraj, M.; Chelliapan, Shreeshivadasan; Noor, Zainura Zainun [Institute of Environmental Water Resources and Management (IPASA), Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Remaz, Dilshah [Faculty of Built Environment, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Iwao, Kenzo [Nagoya Institute of Technology, Nagoya (Japan)

    2012-07-01

    This paper describes the investigation of heat impact on the vertical surfaces of buildings based on their thermal behavior. The study was performed based on four building materials that is commonly used in Malaysia; brick, concrete, granite and white concrete tiles. The thermal performances on the building materials were investigated using a surface temperature sensor, data logging system and infrared thermography. Results showed that the brick had the capability to absorb and store heat greater than other materials during the investigation period. The normalized heat (total heat/solar radiation) of the brick was 0.093 and produces high heat (51% compared to granite), confirming a substantial amount of heat being released into the atmosphere through radiation and convection. The most sensitive material that absorbs and stores heat was in the following order: brick > concrete > granite > white concrete tiles. It was concluded that the type of exterior wall material used in buildings had significant impact to the environment.

  19. A thermal battery and a method for building it

    Energy Technology Data Exchange (ETDEWEB)

    Yamadzaki, K.; Kumano, Y.; Nakanisi, M.; Yamane, T.

    1982-07-14

    Anodes of the thermal battery are made of metallic calcium, while the electrolyte is made from a mixture of a lithium compound with other salts. Granules of an electrolyte carrier are introduced into the electrolyte which in the external part contains a low concentration of the lithium compound and in the interior part, a high concentration of the lithium compound. With activation of the battery, the formation of a calcium and Li2 alloy, which has a low melting point (230C), is limited. The battery has a stable discharge voltage and the formation of short circuits (KZ) in it is prevented, increasing the reliability.

  20. Energy system investment model incorporating heat pumps with thermal storage in buildings and buffer tanks

    DEFF Research Database (Denmark)

    Hedegaard, Karsten; Balyk, Olexandr

    2013-01-01

    be taken into account. In this study, we present a model that facilitates analysing individual heat pumps and complementing heat storages in integration with the energy system, while optimising both investments and operation. The model incorporates thermal building dynamics and covers various heat storage...... options: passive heat storage in the building structure via radiator heating, active heat storage in concrete floors via floor heating, and use of thermal storage tanks for space heating and hot water. It is shown that the model is well qualified for analysing possibilities and system benefits...

  1. New kinds of energy-storing building composite PCMs for thermal energy storage

    International Nuclear Information System (INIS)

    Graphical abstract: In this work, 10 new kinds of BCPCMs were prepared by blending of liquid xylitol pentalaurate (XPL) and xylitol pentamyristate (XPM) esters into gypsum, cement, diatomite, perlite and vermiculite. DSC results showed that the melting temperatures and energy storage capacities of the prepared BCPCMs are in range of about 40–55 °C and 31–126 J/g, respectively. TG investigations and thermal cycling test showed that the BCPCMs had good thermal endurance and thermal reliability. It can be also concluded that among the prepared 10 kinds materials, especially the BCPCMs including perlite, vermiculite, diatomite were found to better candidates for thermal energy storage applications in buildings due to the fact that they have relatively high heat storage ability. Highlights: ► New kinds BCPCMs were prepared by blending of liquid XPL and XPM esters with some building materials. ► The BCPCMs had suitable melting temperatures and energy storage capacities. ► Especially, the BCPCMs including perlite, vermiculite, diatomite were found to better candidates for thermal energy storage. - Abstract: Energy storing-composite phase change materials (PCMs) are significant means of thermal energy storage in buildings. Although several building composite PCMs (BCPCMs) have been developed in recent years, the additional investigations are still required to enrich the diversity of BCPCMs for solar heating and energy conservation applications in buildings. For this purpose, the present work is focused the preparation, characterization and determination of 10 new kinds of BCPCMs. The BCPCMs were prepared by blending of liquid xylitol pentalaurate (XPL) and xylitol pentamyristate (XPM) esters with gypsum, cement, diatomite, perlite and vermiculite as supporting matrices. The scanning electron microscopy (SEM) and Fourier Transform Infrared (FT-IR) analysis showed that the ester compounds were adsorbed uniformly into the building materials due to capillary forces

  2. Modeling of hydronic radiant cooling of a thermally homeostatic building using a parametric cooling tower

    International Nuclear Information System (INIS)

    Highlights: • Investigated cooling of thermally homeostatic buildings in 7 U.S. cities by modeling. • Natural energy is harnessed by cooling tower to extract heat for building cooling. • Systematically studied possibility and conditions of using cooling tower in buildings. • Diurnal ambient temperature amplitude is taken into account in cooling tower cooling. • Homeostatic building cooling is possible in locations with large ambient T amplitude. - Abstract: A case is made that while it is important to mitigate dissipative losses associated with heat dissipation and mechanical/electrical resistance for engineering efficiency gain, the “architect” of energy efficiency is the conception of best heat extraction frameworks—which determine the realm of possible efficiency. This precept is applied to building energy efficiency here. Following a proposed process assumption-based design method, which was used for determining the required thermal qualities of building thermal autonomy, this paper continues this line of investigation and applies heat extraction approach investigating the extent of building partial homeostasis and the possibility of full homeostasis by using cooling tower in one summer in seven selected U.S. cities. Cooling tower heat extraction is applied parametrically to hydronically activated radiant-surfaces model-buildings. Instead of sizing equipment as a function of design peak hourly temperature as it is done in heat balance design-approach of selecting HVAC equipment, it is shown that the conditions of using cooling tower depend on both “design-peak” daily-mean temperature and the distribution of diurnal range in hourly temperature (i.e., diurnal temperature amplitude). Our study indicates that homeostatic building with natural cooling (by cooling tower alone) is possible only in locations of special meso-scale climatic condition such as Sacramento, CA. In other locations the use of cooling tower alone can only achieve homeostasis

  3. Meteorological simulation of thermal environment in the Sichuan basin

    Institute of Scientific and Technical Information of China (English)

    HongbinZHANG; KeisukeHANAKI; ToshiyaARAMAKI

    2003-01-01

    A highly versatile numerical code - the Regional Atmospheric Modeling System (RAMS) was used into the heat island simulation of an inland mega-city - Chongqing and Sichuan Basin, China. The entire horizontal calculation domain 2000 km×2000 km and the vertical calculation domain was from 50cm under ground to the altitude of 15 000 m. The USGS (U.S.Geological Survey) topography and land use data, the NCEP (National Centers for Environmental Prediction) meteorological data were used as the input data of this simulation. The simulation shows that the temperature of Chongqing''s urban area was higher than that of suburb area corresponding to the topographical condition. It was confirmed that RAMS could be applied for the simulation of thermal environment. It was also demonstrated that the local climate in the smaller scale could be expressed by generating two-way interactive nesting grid.

  4. Integrated EM & Thermal Simulations with Upgraded VORPAL Software

    Energy Technology Data Exchange (ETDEWEB)

    D.N. Smithe, D. Karipides, P. Stoltz, G. Cheng, H. Wang

    2011-03-01

    Nuclear physics accelerators are powered by microwaves which must travel in waveguides between room-temperature sources and the cryogenic accelerator structures. The ohmic heat load from the microwaves is affected by the temperature-dependent surface resistance and in turn affects the cryogenic thermal conduction problem. Integrated EM & thermal analysis of this difficult non-linear problem is now possible with the VORPAL finite-difference time-domain simulation tool. We highlight thermal benchmarking work with a complex HOM feed-through geometry, done in collaboration with researchers at the Thomas Jefferson National Accelerator Laboratory, and discuss upcoming design studies with this emerging tool. This work is part of an effort to generalize the VORPAL framework to include generalized PDE capabilities, for wider multi-physics capabilities in the accelerator, vacuum electronics, plasma processing and fusion R&D fields, and we will also discuss user interface and algorithmic upgrades which facilitate this emerging multiphysics capability.

  5. Building interactive simulations in a Web page design program.

    Science.gov (United States)

    Kootsey, J Mailen; Siriphongs, Daniel; McAuley, Grant

    2004-01-01

    A new Web software architecture, NumberLinX (NLX), has been integrated into a commercial Web design program to produce a drag-and-drop environment for building interactive simulations. NLX is a library of reusable objects written in Java, including input, output, calculation, and control objects. The NLX objects were added to the palette of available objects in the Web design program to be selected and dropped on a page. Inserting an object in a Web page is accomplished by adding a template block of HTML code to the page file. HTML parameters in the block must be set to user-supplied values, so the HTML code is generated dynamically, based on user entries in a popup form. Implementing the object inspector for each object permits the user to edit object attributes in a form window. Except for model definition, the combination of the NLX architecture and the Web design program permits construction of interactive simulation pages without writing or inspecting code. PMID:17271495

  6. Thermal conductivity of model zeolites: molecular dynamics simulation study

    Science.gov (United States)

    Murashov, Vladimir V.

    1999-02-01

    The thermal conductivity of model zeolites was investigated using non-equilibrium molecular dynamics calculations. This type of calculation was found to overestimate the thermal conductivity of low-density silica polymorphs. A better reproduction of the experimental results was found for zeolites, and this was related to the lower phonon mean free path. The thermal conductivity of framework silicates was shown to be determined primarily by the vibrations of the continuous oxygen sublattice. Thus, the most drastic suppression of the heat transfer was related to alterations of the O-O distances; for example, a sixfold reduction in thermal conductivity compared to that of siliceous LTA zeolite was found for LTA-A1PO4. Framework cations were shown to affect the heat transfer by changing the vibrational modes of the structural building units of the framework and non-framework counter-cations, by disturbing the oxygen sublattice locally and acting as Rayleigh and resonant scatterers. A model assuming the heat transfer to be due only to non-dispersive acoustic phonons failed to reproduce the dependence of the thermal conductivity on the mass of the cations and the unit-cell dimension, thus suggesting a more sophisticated mechanism of heat transfer to be operative in framework materials. The effect of non-framework non-ionic species on the thermal conductivity was shown to be determined by their effect on the characteristics of the oxygen framework vibrations. Thus, repulsive interactions between the oxygen sublattice and Xe8 clusters, reducing the anisotropy and anharmonicity of the oxygen vibrations, give rise to enhanced heat transfer in LTA-SiO2 at ambient conditions.

  7. Evaluation of thermal resistance of building insulations with reflective surfaces

    Science.gov (United States)

    Št'astník, S.

    2012-09-01

    The thermal resistance of advanced insulation materials, applied namely in civil engineering, containing reflective surfaces and air gaps, cannot be evaluated correctly using the valid European standards because of presence of the dominant nonlinear radiative heat transfer and other phenomena not included in the recommended computational formulae. The proper general physical analysis refers to rather complicated problems from classical thermodynamics, whose both existence theory and numerical analysis contain open questions and cannot be done in practice when the optimization of composition of insulation layers is required. This paper, coming from original experimental results, demonstrates an alternative simplified computational approach, taking into account the most important physical processes, useful in the design of modern insulation systems.

  8. Numerical simulation for thermal flow filling process of casting

    Institute of Scientific and Technical Information of China (English)

    CHEN Ye; ZHAO Yu-hong; HOU Hua

    2006-01-01

    The solution algorithm (SOLA) method was used to solve the velocity and pressure field of the thermal flow filling process, and the volume of fluid (VOF) method for the free surface problem. Since the "donor-acceptor" rule often results in the free interface vague, the explicit difference method was adopted, and a method describing the free surface state at 0<F<1 was proposed to deal with this problem. In order to raise the computation efficiency, such algorithms were investigated and invalidated as: 1) internal and external area separation simplification algorithm; 2) the reducing necessary search area method. With the improved algorithms, the filling processes of the valve cover castings with gravity cast and an up cylinder block casting with low-pressure cast were simulated, the simulation results are believable and the computation efficiency is greatly improved. The SOLA-VOF model and its difference method for thermal fluid flow filling process were introduced.

  9. Simulation of collision cascades and thermal spikes in ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Devanathan, Ramaswami; Weber, William J.

    2010-10-01

    Classical molecular dynamics simulations have been employed to examine defect production by energetic recoils in UO2, Gd2Ti2O7, Gd2Zr2O7 and ZrSiO4. These atomistic simulations provide details of the nature and size distribution of defect clusters produced in collision cascades. The accommodation of recoil damage by lower energy cation exchange and greater occupation of anion structural vacancies is a contributing factor for the greater radiation tolerance of Gd2Zr2O7 relative to Gd2Ti2O7. In addition, electronic energy loss processes in UO2 has been modeled in the form of a thermal spike to study the details of track formation and track structure. For thermal spikes with energy deposition of 4 keV/nm in UO2, a track was not formed and mainly isolated Frenkel pairs are produced.

  10. Evaluating local and overall thermal comfort in buildings using thermal manikins

    Energy Technology Data Exchange (ETDEWEB)

    Foda, E.

    2012-07-01

    Evaluation methods of human thermal comfort that are based on whole-body heat balance with its surroundings may not be adequate for evaluations in non-uniform thermal conditions. Under these conditions, the human body's segments may experience a wide range of room physical parameters and the evaluation of the local (segmental) thermal comfort becomes necessary. In this work, subjective measurements of skin temperature were carried out to investigate the human body's local responses due to a step change in the room temperature; and the variability in the body's local temperatures under different indoor conditions and exposures as well as the physiological steady state local temperatures. Then, a multi-segmental model of human thermoregulation was developed based on these findings to predict the local skin temperatures of individuals' body segments with a good accuracy. The model predictability of skin temperature was verified for steady state and dynamic conditions using measured data at uniform neutral, cold and warm as well as different asymmetric thermal conditions. The model showed very good predictability with average absolute deviation ranged from 0.3-0.8 K. The model was then implemented onto the control system of the thermal manikin 'THERMINATOR' to adjust the segmental skin temperature set-points based on the indoor conditions. This new control for the manikin was experimentally validated for the prediction of local and overall thermal comfort using the equivalent temperature measure. THERMINATOR with the new control mode was then employed in the evaluation of localized floor-heating system variants towards maximum energy efficiency. This aimed at illustrating a design strategy using the thermal manikin to find the optimum geometry and surface area of a floor-heater for a single seated person. Furthermore, a psychological comfort model that is based on local skin temperature was adapted for the use with the model of human

  11. Simulation of diurnal thermal energy storage systems: Preliminary results

    Science.gov (United States)

    Katipamula, S.; Somasundaram, S.; Williams, H. R.

    1994-12-01

    This report describes the results of a simulation of thermal energy storage (TES) integrated with a simple-cycle gas turbine cogeneration system. Integrating TES with cogeneration can serve the electrical and thermal loads independently while firing all fuel in the gas turbine. The detailed engineering and economic feasibility of diurnal TES systems integrated with cogeneration systems has been described in two previous PNL reports. The objective of this study was to lay the ground work for optimization of the TES system designs using a simulation tool called TRNSYS (TRaNsient SYstem Simulation). TRNSYS is a transient simulation program with a sequential-modular structure developed at the Solar Energy Laboratory, University of Wisconsin-Madison. The two TES systems selected for the base-case simulations were: (1) a one-tank storage model to represent the oil/rock TES system; and (2) a two-tank storage model to represent the molten nitrate salt TES system. Results of the study clearly indicate that an engineering optimization of the TES system using TRNSYS is possible. The one-tank stratified oil/rock storage model described here is a good starting point for parametric studies of a TES system. Further developments to the TRNSYS library of available models (economizer, evaporator, gas turbine, etc.) are recommended so that the phase-change processes is accurately treated.

  12. Simulation of diurnal thermal energy storage systems: Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Katipamula, S.; Somasundaram, S. [Pacific Northwest Lab., Richland, WA (United States); Williams, H.R. [Univ. of Alaska, Fairbanks, AK (United States). Dept. of Mechanical Engineering

    1994-12-01

    This report describes the results of a simulation of thermal energy storage (TES) integrated with a simple-cycle gas turbine cogeneration system. Integrating TES with cogeneration can serve the electrical and thermal loads independently while firing all fuel in the gas turbine. The detailed engineering and economic feasibility of diurnal TES systems integrated with cogeneration systems has been described in two previous PNL reports. The objective of this study was to lay the ground work for optimization of the TES system designs using a simulation tool called TRNSYS (TRaNsient SYstem Simulation). TRNSYS is a transient simulation program with a sequential-modular structure developed at the Solar Energy Laboratory, University of Wisconsin-Madison. The two TES systems selected for the base-case simulations were: (1) a one-tank storage model to represent the oil/rock TES system, and (2) a two-tank storage model to represent the molten nitrate salt TES system. Results of the study clearly indicate that an engineering optimization of the TES system using TRNSYS is possible. The one-tank stratified oil/rock storage model described here is a good starting point for parametric studies of a TES system. Further developments to the TRNSYS library of available models (economizer, evaporator, gas turbine, etc.) are recommended so that the phase-change processes is accurately treated.

  13. APPLICATION OF DYNAMIC SIMULATIONS IN THE ANALYSIS OF MEASURES FOR IMPROVING ENERGY EFFICIENCY OF BUILDINGS

    OpenAIRE

    DRAGICEVIC SNEZANA M.

    2016-01-01

    One of the most commonly used methods for improving energy performances of buildings is reducing heating energy consumption. This paper shows a comparative analysis of building energy demand for space heating based on case studies in which building modifications were made with insulating materials of building envelopes and with different window types. For the analysis, a public building with 6 floors, located in Belgrade, was selected. For a dynamical simulation and evaluation of the applied ...

  14. Mathematical modelling and simulation of the thermal performance of a solar heated indoor swimming pool

    Directory of Open Access Journals (Sweden)

    Mančić Marko V.

    2014-01-01

    Full Text Available Buildings with indoor swimming pools have a large energy footprint. The source of major energy loss is the swimming pool hall where air humidity is increased by evaporation from the pool water surface. This increases energy consumption for heating and ventilation of the pool hall, fresh water supply loss and heat demand for pool water heating. In this paper, a mathematical model of the swimming pool was made to assess energy demands of an indoor swimming pool building. The mathematical model of the swimming pool is used with the created multi-zone building model in TRNSYS software to determine pool hall energy demand and pool losses. Energy loss for pool water and pool hall heating and ventilation are analyzed for different target pool water and air temperatures. The simulation showed that pool water heating accounts for around 22%, whereas heating and ventilation of the pool hall for around 60% of the total pool hall heat demand. With a change of preset controller air and water temperatures in simulations, evaporation loss was in the range 46-54% of the total pool losses. A solar thermal sanitary hot water system was modelled and simulated to analyze it's potential for energy savings of the presented demand side model. The simulation showed that up to 87% of water heating demands could be met by the solar thermal system, while avoiding stagnation. [Projekat Ministarstva nauke Republike Srbije, br. III 42006: Research and development of energy and environmentally highly effective polygeneration systems based on using renewable energy sources

  15. Evaluation of Various Retrofitting Concepts of Building Envelope for Offices Equipped with Large Radiant Ceiling Panels by Dynamic Simulations

    Directory of Open Access Journals (Sweden)

    Sabina Jordan

    2015-09-01

    Full Text Available In order to achieve significant savings in energy and an improved level of thermal comfort in retrofitted existing buildings, specific retrofitting concepts that combine new technologies and design need to be developed and implemented. Large radiant surfaces systems are now among the most promising future technologies to be used both in retrofitted and in new low-energy buildings. These kinds of systems have been the topic of several studies dealing with thermal comfort and energy utilization, but some specific issues concerning their possible use in various concepts for retrofitting are still poorly understood. In the present paper, some results of dynamic simulations, with the transient system simulation tool (TRNSYS model, of the retrofitted offices equipped with radiant ceiling panels are presented and thoroughly analysed. Based on a precise comparison of the results of these simulations with actual measurements in the offices, certain input data for the model were added, so that the model was consequently validated. The model was then applied to the evaluation of various concepts of building envelopes for office retrofitting. By means of dynamic simulations of indoor environment it was possible to determine the benefits and limitations of individual retrofitting concepts. Some specific parameters, which are relevant to these concepts, were also identified.

  16. Overall Thermal Performance of Flexible Piping Under Simulated Bending Conditions

    Science.gov (United States)

    Fesmire, James E.; Augustynowicz, S. D.; Demko, J. A.; Thompson, Karen (Technical Monitor)

    2001-01-01

    Flexible, vacuum-insulated transfer lines for low-temperature applications have higher thermal losses than comparable rigid lines. Typical flexible piping construction uses corrugated tubes, inner and outer, with a multilayer insulation (MLI) system in the annular space. Experiments on vacuum insulation systems in a flexible geometry were conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The effects of bending were simulated by causing the inner tube to be eccentric with the outer tube. The effects of spacers were simulated in a controlled way by inserting spacer tubes for the length of the cylindrical test articles. Two material systems, standard MLI and a layered composite insulation (LCI), were tested under the full range of vacuum levels using a liquid nitrogen boiloff calorimeter to determine the apparent thermal conductivity (k-value). The results indicate that the flexible piping under simulated bending conditions significantly degrades the thermal performance of the insulation system. These data are compared to standard MLI for both straight and flexible piping configurations. The definition of an overall k-value for actual field installations (k(sub oafi)) is described for use in design and analysis of cryogenic piping systems.

  17. Thermal Performance of Typical Residential Building in Karachi with Different Materials for Construction

    Directory of Open Access Journals (Sweden)

    Nafeesa Shaheen

    2016-04-01

    Full Text Available This research work deals with a study of a residential building located in climatic context of Karachi with the objective of being the study of thermal performance based upon passive design techniques. The study helps in reducing the electricity consumption by improving indoor temperatures. The existing residential buildings in Karachi were studied with reference to their planning and design, analyzed and evaluated. Different construction?s compositions of buildings were identified, surveyed and analyzed in making of the effective building envelops. Autodesk® Ecotect, 2011 was used to determine indoor comfort conditions and HVAC (Heating, Ventilation, Air-Conditioning and Cooling loads. The result of the research depicted significant energy savings of 38.5% in HVAC loads with proposed building envelop of locally available materials and glazing.

  18. Dynamic thermal simulation on retrofitting scenarios for semi-extensive sheep farms

    Directory of Open Access Journals (Sweden)

    Maria E. Menconi

    2014-10-01

    Full Text Available Sheep and goat have a high adaptability to different climatic conditions. Nevertheless, even in extensive farming, these species benefit from the presence of structures that can mitigate stress from heat, cold and humidity changes. These shelters are used at night or for limited periods during the year. These are characterised by a low engineering and make extensive use of recycled material. Interesting innovation in rural areas could be represented by the re-development of these buildings in order to improve their internal microclimate. This work develops a thermal dynamic simulation model aimed at identifying the best solution to retrofit the envelope of existing livestock buildings. In this paper, three different solutions have been tested: insulation of vertical surfaces, insulation of roof and window type. Eight different materials have been considered for roof and vertical surfaces and four for the different kind of window glazing, analysing the building microclimate responses. As a reference building to compare the different solutions adopted has been chosen an extensive sheep farm located in the Italian Apennines. The results suggest that the best solution is to insulate the roof. The other elements offer negligible results in term of improving the internal microclimate conditions. For coating the roof it can also be considered a good response of all the analysed insulating materials, in order to increase the period of maintaining the temperature of comfort and not exceeding its critical values within the building.

  19. Characterizing the spatiotemporal evolution of building-stock age in Poultney, Vermont: a GIS-based approach to improve thermal efficiency in historical buildings

    OpenAIRE

    John Van Hoesen; Steven Letendre

    2013-01-01

    Many industrialized countries are exploring ways to facilitate the prioritization of efforts targeting improved thermal efficiency in an aging building stock. Older buildings, typically, have inefficient building envelopes and higher energy-consumption patterns relative to new construction, which contributes to higher overall energy consumption at the local and regional scale. Reducing energy consumption by increasing the efficiency of older buildings will result in lower anthropogenic greenh...

  20. Identification of the main thermal characteristics of building components using MATLAB

    DEFF Research Database (Denmark)

    Jimenez, M.J.; Madsen, Henrik; Andersen, Klaus Kaae

    2008-01-01

    This paper presents the application of the IDENT Graphical User Interface of MATLAB to estimate the thermal properties of building components from outdoor dynamic testing, imposing appropriate physical constraints and assuming linear and time invariant parametric models. The theory is briefly...

  1. Thermal energy storage - A review of concepts and systems for heating and cooling applications in buildings

    DEFF Research Database (Denmark)

    Pavlov, Georgi Krasimiroy; Olesen, Bjarne W.

    2012-01-01

    The use of thermal energy storage (TES) in buildings in combination with space heating and/or space cooling has recently received much attention. A variety of TES techniques have developed over the past decades. TES systems can provide short-term storage for peak-load shaving as well as long-term...

  2. Thermal and Daylighting Performance of Energy-Efficient Windows in Highly Glazed Residential Buildings: Case Study in Korea

    Directory of Open Access Journals (Sweden)

    Chang Heon Cheong

    2014-10-01

    Full Text Available Cooling load in highly glazed residential building can be excessively large due to uncontrolled solar energy entering the indoor space. This study focuses on the cooling load reduction and changes in the daylighting properties via the application of a double window system (DWS with shading with various surface reflectivities in highly glazed residential buildings. Evaluation of thermal and daylighting performances is carried out using simulation tools. The reductions in cooling load and energy cost through the use of DWS are evaluated through a comparative simulation considering conventional windows: a single window and a double window. Three variables of window types, natural ventilation, and shading reflectivity are reflected in the study. According to our results, implementation of DWS reduced cooling load by 43%–61%. Electricity cost during the cooling period was reduced by a maximum of 24%. However, a shading device setting that prioritizes effective cooling load reduction can greatly decrease the daylighting factor and luminance level of indoor space. A DWS implementing shading device with highly reflective at all surfaces is appropriate option for the more comfortable thermal and visual environment, while a shading device with low reflectivity at rear of the surface can contribute an additional 4% cooling load reduction.

  3. Characterizing Thermal Properties of Melting Te Semiconductor: Thermal Diffusivity Measurements and Simulation

    Science.gov (United States)

    Zhu, Shen; Su, Ching-Hua; Li, C.; Lin, B.; Ben, H.; Scripa, R. N.; Lehoczky, S. L.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Tellurium is an element for many II-VI and I-III-VI(sub 2) compounds that are useful materials for fabricating many devises. In the melt growth techniques, the thermal properties of the molten phase are important parameter for controlling growth process to improve semiconducting crystal quality. In this study, thermal diffusivity of molten tellurium has been measured by a laser flash method in the temperature range from 500 C to 900 C. A pulsed laser with 1064 nm wavelength is focused on one side of the measured sample. The thermal diffusivity can be estimated from the temperature transient at the other side of the sample. A numerical simulation based on the thermal transport process has been also performed. By numerically fitting the experimental results, both the thermal conductivity and heat capacity can be derived. A relaxation phenomenon, which shows a slow drift of the measured thermal conductivity toward the equilibrium value after cooling of the sample, was observed for the first time. The error analysis and the comparison of the results to published data measured by other techniques will be discussed in the presentation.

  4. Minerve: thermal-hydraulic phenomena simulation and virtual reality

    International Nuclear Information System (INIS)

    MINERVE is a 3D interactive application representing the thermal-hydraulic phenomena happening in a nuclear plant. Therefore, the 3D geometric model of the French 900 MW PWR installations has been built. The users can interact in real time with this model to see at each step of the simulation what happens in the pipes. The thermal-hydraulic simulation is made by CATHARE-2, which calculates at every time step data on about one thousand meshes (the whole primary circuit, a part of the second circuit, and the Residual Heat Removal System). The simulation covers incidental and accidental cases on these systems. There are two main innovations in MINERVE: In the domain of nuclear plant's visualization, it is to introduce interactive 3D software mechanisms to visualize results of a physical simulation. In the domain of real-time 3D, it is to visualize fluids in a pipe, while they can have several configurations, like bubbles or single liquid phase. These mechanisms enable better comprehension and better visual representation of the possible phenomena. This paper describes the functionalities of MINERVE, and the difficulties to represent fluids with several characteristics like speed, configuration,..., in 3D. On the end, we talk about the future of MINERVE, and more widely of the possible futures of such an application in scientific visualization. (authors)

  5. Thermal hydraulic simulations, error estimation and parameter sensitivity studies in Drekar::CFD

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Thomas Michael; Shadid, John N; Pawlowski, Roger P; Cyr, Eric C; Wildey, Timothy Michael

    2014-01-01

    This report describes work directed towards completion of the Thermal Hydraulics Methods (THM) CFD Level 3 Milestone THM.CFD.P7.05 for the Consortium for Advanced Simulation of Light Water Reactors (CASL) Nuclear Hub effort. The focus of this milestone was to demonstrate the thermal hydraulics and adjoint based error estimation and parameter sensitivity capabilities in the CFD code called Drekar::CFD. This milestone builds upon the capabilities demonstrated in three earlier milestones; THM.CFD.P4.02 [12], completed March, 31, 2012, THM.CFD.P5.01 [15] completed June 30, 2012 and THM.CFD.P5.01 [11] completed on October 31, 2012.

  6. Simulation, optimization and control of a thermal cracking furnace

    Energy Technology Data Exchange (ETDEWEB)

    Masoumi, M.E.; Sadrameli, S.M.; Towfighi, J. [Chemical Engineering Department, Tarbiat Modarres University, P.O. Box 14115-143, Tehran, Iran (Iran); Niaei, A. [Department of Applied Chemistry, University of Tabriz, 51666-14766 Tabriz, Iran (Iran)

    2006-03-01

    The ethylene production process is one of the most important aspect of a petrochemical plant and the cracking furnace is the heart of the process. Since, ethylene is one of the raw materials in the chemical industry and the market situation of not only the feed and the product, but also the utility is rapidly changing, the optimal operation and control of the plant is important. A mathematical model, which describes the static and dynamic operations of a pilot plant furnace, was developed. The static simulation was used to predict the steady-state profiles of temperature, pressure and products yield. The dynamic simulation of the process was used to predict the transient behavior of thermal cracking reactor. Using a dynamic programming technique, an optimal temperature profile was developed along the reactor. Performances of temperature control loop were tested for different controller parameters and disturbances. The results of the simulation were tested experimentally in a computer control pilot plant. (author)

  7. An experimental and simulation study on build thickness dependent microstructure for electron beam melted Ti–6Al–4V

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Xipeng, E-mail: xptan1985@gmail.com [Singapore Centre for 3D Printing, School of Mechanical & Aerospace Engineering, Nanyang Technological University, HW1-01-05, 2A Nanyang Link, 637372 Singapore (Singapore); Kok, Yihong; Tan, Yu Jun [Singapore Centre for 3D Printing, School of Mechanical & Aerospace Engineering, Nanyang Technological University, HW1-01-05, 2A Nanyang Link, 637372 Singapore (Singapore); Vastola, Guglielmo, E-mail: vastolag@ihpc.a-star.edu.sg [Institute of High Performance Computing, A*Star, 1 Fusionopolis Way, #16-16 Connexis, 138632 Singapore (Singapore); Pei, Qing Xiang; Zhang, Gang; Zhang, Yong-Wei [Institute of High Performance Computing, A*Star, 1 Fusionopolis Way, #16-16 Connexis, 138632 Singapore (Singapore); Tor, Shu Beng; Leong, Kah Fai; Chua, Chee Kai [Singapore Centre for 3D Printing, School of Mechanical & Aerospace Engineering, Nanyang Technological University, HW1-01-05, 2A Nanyang Link, 637372 Singapore (Singapore)

    2015-10-15

    Build thickness dependent microstructure of electron beam melted (EBM{sup ®}) Ti–6Al–4V has been investigated from both experiment and simulation using four block samples with thicknesses of 1, 5, 10 and 20 mm. We observe a mixed microstructure of alternate α/β with some α′ martensite inside the 1 mm-thick sample. By contrast, only the alternate α/β microstructure with both colony and basket-weave morphologies occurs inside the 5 mm-, 10 mm- and 20 mm-thick samples. It is found that β spacing is constantly increased with the build thickness, leading to an obvious decrease in microhardness. Finite element method (FEM) simulations show that cooling rates and thermal profiles during EBM process are favorable for the formation of martensite. Moreover, full-scale FEM simulations reveal that the average temperature inside the samples is higher as the build thickness increases. It suggests that martensitic decomposition is faster in thicker samples, which is in good agreement with the experimental observations. - Highlights: • Build geometry dependent microstructure and microhardness for EBM-built Ti–6Al–4V. • Phase evolution involved in EBM process. • FEM simulation of EBM process. • α′ martensite formation and its identification.

  8. An experimental and simulation study on build thickness dependent microstructure for electron beam melted Ti–6Al–4V

    International Nuclear Information System (INIS)

    Build thickness dependent microstructure of electron beam melted (EBM®) Ti–6Al–4V has been investigated from both experiment and simulation using four block samples with thicknesses of 1, 5, 10 and 20 mm. We observe a mixed microstructure of alternate α/β with some α′ martensite inside the 1 mm-thick sample. By contrast, only the alternate α/β microstructure with both colony and basket-weave morphologies occurs inside the 5 mm-, 10 mm- and 20 mm-thick samples. It is found that β spacing is constantly increased with the build thickness, leading to an obvious decrease in microhardness. Finite element method (FEM) simulations show that cooling rates and thermal profiles during EBM process are favorable for the formation of martensite. Moreover, full-scale FEM simulations reveal that the average temperature inside the samples is higher as the build thickness increases. It suggests that martensitic decomposition is faster in thicker samples, which is in good agreement with the experimental observations. - Highlights: • Build geometry dependent microstructure and microhardness for EBM-built Ti–6Al–4V. • Phase evolution involved in EBM process. • FEM simulation of EBM process. • α′ martensite formation and its identification

  9. Regulation and control of thermally activated building systems (TABS); Regelung und Steuerung von thermoaktiven Bauteilsystemen (TABS)

    Energy Technology Data Exchange (ETDEWEB)

    Toedtli, Juerg [Consulting Juerg Toedtli, Zuerich (Switzerland); Gwerder, Markus; Renggli, Franz; Guentensperger, Werner [Siemens Building Technologies, Zug (Switzerland); Lehmann, Beat; Dorer, Viktor [Empa, Abt. Building Technologies, Duebendorf (Switzerland); Hildebrand, Kurt [Hochschule Luzern - Technik and Architektur, Horw (Switzerland)

    2009-10-15

    Thermally activated building systems (TABS) are becoming increasingly important in terms of energy efficient cooling and heating of buildings. In practice, however, regulation and control of such systems often causes problems. Started five years ago with the aim of getting to grips with these problems, the TABS Control research project was completed in early 2009. The project yielded the following results: various models and simulation programs for TABS; performance-bound calculations for regulating zones; a range of zone regulation/control strategies for planners to choose from, including good solutions for automatic switching between heating and cooling, for pulsed operation of the zone pump and for room temperature control; the implementation of a subset of these strategies as standard solutions in a Siemens building automation system; laboratory tests on these strategies; a new procedure for the integrated planning of TABS and their regulation/control (referred to as UBB planning procedure - Unknown But Bounded); an Excel planning tool; guidelines on selecting the hydraulic switching topology; a method for operation optimization; the theoretical basis for the new integrated planning procedure and the new regulation/ control strategies; a patent application. [German] Thermoaktive Bauteilsysteme (TABS) haben eine zunehmende Bedeutung bei der energieeffizienten Kuehlung und Heizung von Gebaeuden, doch ihre Regelung/Steuerung fuehrt in der Praxis oft zu Problemen. Mit dem Ziel, diese Probleme in den Griff zu bekommen, wurde vor fuenf Jahren das Forschungsprojekt TABS-Control gestartet, das zu Beginnd des Jahres 2009 abgeschlossen wurde. Es wurden folgende wesentliche Resultate erarbeitet: Modelle und Simulationsprogramme fuer TABS; Performance-Bound-Berechnungen fuer die Zonenregelung; eine Auswahl von Regel-/ Steuer-Strategien fuer die Zonenregelung, u. a. mit Loesungen fuer das automatische Umschalten zwischen Heizen und Kuehlen, fuer den Taktbetrieb der

  10. Comparative Thermal Analysis of Different Cool Roof Materials for Minimizing Building Energy Consumption

    Directory of Open Access Journals (Sweden)

    Y. Anand

    2014-01-01

    Full Text Available The roof and walls in the urban areas contribute to major share in the absorption of solar radiations and also retard the outflow of the absorbed radiation from the building envelope, thereby increasing the global warming by inducing the heat island effect. The impact of using cool roof technologies on the thermal comfort of the office buildings has been estimated. Cool roofs reduce electricity consumption for maintaining the temperature of the air-conditioned buildings in the comfort level and also increase comfort in buildings merely not relying completely on cooling equipment. The cool roofs and cool pavements, however, can mitigate summer urban heat islands by improving indoor air quality and comfort. The thermal analysis of different materials has been carried out to analyze the impact of the rate of heat transfer on the building envelope and the results obtained indicate that different cool roof techniques are beneficial in maintaining the comfort level of the building which purely depends on the ambient temperature conditions.

  11. Computer simulation for better design and operation of large office building air-conditioning

    NARCIS (Netherlands)

    Lain, M.; Hensen, J.; Zmrhal, V.

    2009-01-01

    The paper deals with the use of computer simulations both for the design support of a new buildings and HVAC system development and for the optimisation of the system control strategy in the building. This is presented on a real office building in Prague. For a new large bank head office in Prague,

  12. DSMC Simulation of Microstructure Actuation by Knudsen Thermal Force

    Science.gov (United States)

    Pikus, Aaron; Sebastiao, Israel; Strongrich, Andrew; Alexeenko, Alina

    2015-11-01

    Compact, low-power and highly accurate vacuum sensors are needed for emerging applications such as high-altitude communication platforms, small satellites and in-vacuum manufacturing processes. A novel MEMS-based pressure and gas sensor - Microelectromechanical In-plane Knudsen Radiometric Actuator (MIKRA) - has been developed at Purdue. MIKRA is based on Knudsen thermal force generated by rarefied flow driven by thermal gradients within the microstructure. The goal of this work is to model the rarefied gas flow in the MIKRA sensor to validate the numerical modeling of rarefied thermally-driven flows and gain insights for sensor design. The Direct Simulation Monte Carlo (DSMC) solver SPARTA is employed to numerically calculate the distribution of the flowfield and surface properties. The resulting forces on the colder shuttle beam are calculated and compared to the available experimental data as well as other numerical solvers. Both DSMC and experimental results suggest that the maximum forces occur at a Knudsen number of approximately 1. The streamlines indicate the presence of two small vortexes between the heated beam and the colder shuttle beam, and a larger one above these two beams. The DSMCsimulations, validated by experimental measurements, help understand the unique flow behaviors encountered in rarefied thermally-driven flows. NSF CBET grant #1055453.

  13. Modeling and Simulation of Multi-Room Buildings

    Directory of Open Access Journals (Sweden)

    D.W.U. Perera

    2016-04-01

    Full Text Available Buildings are one of the largest energy consumers in the world which accounts for nearly 40% of the total global energy consumption. In the countries where cold climate conditions predominate, space heating is the key contributor to the increased energy consumption. Today there is a growing trend to use Building Energy Management Systems (BEMS to control the energy consumption of buildings in an efficient manner. BEMS require a good heating model of the building to be integrated for better control purposes. This article refers to the development of different types of physics based buillding heating models, regarding single-zone, multi-floor and multi-room buildings. They address the propriety of each model in building heating control concerning the prediction accuracy and the prediction time. These models are verified for a residential building having three floors. According to the results, the multi-floor model is recognized to have the best qualifications obliged as a model for control.

  14. The Effect Of Thermal Insulation Of An Apartment Building On The Thermo-Hydraulic Stability Of Its Heating System

    Directory of Open Access Journals (Sweden)

    Kurčová Mária

    2015-12-01

    Full Text Available The contribution aims to investigate the effect of the decreased thermal losses of an apartment building due to the thermal insulation of opaque external building constructions and the replacement of transparent constructions. It emphasizes the effect of the thermal characteristics of external constructions on the functionality of the existing heating system in the building and the related requirements for the renovation of the heating system in order to ensure the hydraulic stability of the system and the thermal comfort of the inhabitants.

  15. A cellular automaton based model simulating HVAC fluid and heat transport in a building. Modeling approach and comparison with experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Saiz, A. [Department of Applied Mathematics, Polytechnic University of Valencia, ETSGE School, Camino de Vera s/n, 46022 Valencia (Spain); Urchueguia, J.F. [Department of Applied Physics, Polytechnic University of Valencia, ETSII School, Camino de Vera s/n, 46022 Valencia (Spain); Martos, J. [Superior Technical School of Engineering, Department of Electronic Engineering, University of Valencia, Vicente Andres Estelles s/n, Burjassot 46100, Valencia (Spain)

    2010-09-15

    A discrete model characterizing heat and fluid flow in connection with thermal fluxes in a building is described and tested against experiment in this contribution. The model, based on a cellular automaton approach, relies on a set of a few quite simple rules and parameters in order to simulate the dynamic evolution of temperatures and energy flows in any water or brine based thermal energy distribution network in a building or system. Using an easy-to-record input, such as the instantaneous electrical power demand of the heating or cooling system, our model predicts time varying temperatures in characteristic spots and the related enthalpy flows whose simulation usually requires heavy computational tools and detailed knowledge of the network elements. As a particular example, we have applied our model to simulate an existing fan coil based hydronic heating system driven by a geothermal heat pump. When compared to the experimental temperature and thermal energy records, the outcome of the model coincides. (author)

  16. Comparisons between different models for thermal simulation of GTAW process

    Institute of Scientific and Technical Information of China (English)

    Xu Yanli; Wei Yanhong

    2005-01-01

    Two mathematical models are built to study the effects of the fluid flow on thermal distributions of the gas tungsten arc welding(GTAW) process. One model is based on the heat conductivity equation, which doesn' t take the effects of the fluid flow into account, and the other couples the laminar heat transfer and fluid flow in the weld pool, which is called laminar fluid flow model in short. The simulated results of the two models show that the pattern and velocity of the fluid flow play a critical role in determining the thermal distribution and the weld pool shape. For the laminar fluid flow model, its highest temperature is 400 K lower than that calculated with the other model and the depth of its weld pool is shallower too, which is mainly caused by the main vortex of the flow in the weld pool.

  17. True Concurrent Thermal Engineering Integrating CAD Model Building with Finite Element and Finite Difference Methods

    Science.gov (United States)

    Panczak, Tim; Ring, Steve; Welch, Mark

    1999-01-01

    Thermal engineering has long been left out of the concurrent engineering environment dominated by CAD (computer aided design) and FEM (finite element method) software. Current tools attempt to force the thermal design process into an environment primarily created to support structural analysis, which results in inappropriate thermal models. As a result, many thermal engineers either build models "by hand" or use geometric user interfaces that are separate from and have little useful connection, if any, to CAD and FEM systems. This paper describes the development of a new thermal design environment called the Thermal Desktop. This system, while fully integrated into a neutral, low cost CAD system, and which utilizes both FEM and FD methods, does not compromise the needs of the thermal engineer. Rather, the features needed for concurrent thermal analysis are specifically addressed by combining traditional parametric surface based radiation and FD based conduction modeling with CAD and FEM methods. The use of flexible and familiar temperature solvers such as SINDA/FLUINT (Systems Improved Numerical Differencing Analyzer/Fluid Integrator) is retained.

  18. Molecular dynamics simulation of effective thermal conductivity and study of enhanced thermal transport mechanism in nanofluids

    Science.gov (United States)

    Sarkar, Suranjan; Selvam, R. Panneer

    2007-10-01

    Nanofluids have been proposed as a route for surpassing the performance of currently available heat transfer liquids in the near future. In this study an equilibrium molecular dynamics simulation was used to model a nanofluid system. The thermal conductivity of the base fluid and nanofluid was computed using the Green-Kubo method for various volume fractions of nanoparticle loadings. This study showed the ability of molecular dynamics to predict the enhanced thermal conductivity of nanofluids. Through molecular dynamics calculation of mean square displacements for liquid phase in base fluid and for liquid and solid phases in nanofluid, this study tried to investigate the mechanisms involved in thermal transport of nanofluids at the atomic level. The result showed that the thermal transport enhancement of nanofluids was mostly due to the increased movement of liquid atoms in the presence of nanoparticle. Diffusion coefficients were also calculated for base fluid and nanofluids. Similarity of enhancement in thermal conductivity and diffusion coefficient for nanofluids indicates similar transport process for mass and heat.

  19. Simulation-based support for integrated design of new low-energy office buildings

    DEFF Research Database (Denmark)

    Petersen, Steffen

    and building modelling because of the design situation. The method is implemented in an existing building simulation tool. A test case featuring an office located in Copenhagen, Denmark, shows that the suggested method reduces the energy required for heating and ventilation compared to more conventional......This thesis reports on four years of research with the aim to contribute to the implementation of low-energy office buildings with high quality of indoor environment and good total economy. Focus has been on the design decisions made in the early stages of the building design process. The objective...... is to contribute to a development where simulations of building energy performance and indoor environment is used for generating an input to the overall building design process prior to any actual form giving of the building. This input should be considered as one of several similar inputs from other building...

  20. Reflective coatings for interior and exterior of buildings and improving thermal performance

    International Nuclear Information System (INIS)

    Highlights: ► Increase building energy efficiency by optimizing surface optical properties. ► Study different scenarios with both interior and exterior reflective coatings. ► Combined thermal effect of both interior and exterior reflective coatings. -- Abstract: The importance of reducing building energy usage and thriving for more energy efficient architectures, has nurtured creative solutions and smart choices of materials in the last few decades. Among those are optimizing surface optical properties for both interior and exterior claddings of the building. Development in the coil-coating steel industries has now made it possible to allocate correct optical properties for steel clad buildings with improved thermal performance. Although the importance of the exterior coating and solar gain are thoroughly studied in many literatures, the effect of interior cladding are less tackled, especially when considering a combination of both interior and exterior reflective coatings. This paper contemplates the thermal behavior of small cabins with reflective coatings on both interior and exterior cladding, under different conditions and climates with the aim to clarify and point out to the potential energy saving by smart choices of clad coatings.

  1. Building-Related Symptoms, Energy, and Thermal Control in the Workplace: Personal and Open Plan Offices

    Directory of Open Access Journals (Sweden)

    Sally S. Shahzad

    2016-04-01

    Full Text Available This study compared building-related symptoms in personal and open plan offices, where high and low levels of control over the thermal environment were provided, respectively. The individualized approach in Norway provided every user with a personal office, where they had control over an openable window, door, blinds, and thermostat. In contrast, the open plan case studies in the United Kingdom provided control over openable windows and blinds only for limited occupants seated around the perimeter of the building, with users seated away from the windows having no means of environmental control. Air conditioning was deployed in the Norwegian case study buildings, while displacement ventilation and natural ventilation were utilized in the British examples. Field studies of thermal comfort were applied with questionnaires, environmental measurements, and interviews. Users’ health was better in the Norwegian model (28%, while the British model was much more energy efficient (up to 10 times. The follow-up interviews confirmed the effect of lack of thermal control on users’ health. A balanced appraisal was made of energy performance and users’ health between the two buildings.

  2. Modelling, experimentation and simulation of a reversible HP/ORC unit to get a Positive Energy Building

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Quoilin, Sylvain;

    2015-01-01

    This paper presents an innovative building comprising a heat pump connected to a solar roof and a geothermal heat exchanger. This unit is able to invert its cycle and operate as an Organic Rankine Cycle (ORC). The solar roof is producing large amount of heat throughout the year. This allows...... and fluid R134a shows promising performance with a net electrical energy produced over one year reaching 4030 kWh. Following that, a prototype has been built and has proven the feasibility of the technology. Finally, a simulation code including the building, the ground heat exchanger, the thermal energy...... storage, the solar roof and the reversible HP/ORC unit is developed and allows to perform a sensivity analysis. Annual results show that this technology leads to a Positive Energy Building....

  3. Simulation Study for Measuring Thermal Conductivity and Thermal Diffusivity of Nanofluid Using Hot Wire—Laser Probe Beam Displacement Technique

    Science.gov (United States)

    Yunus, W. Mahmood Mat; Ali, Faris Mohammed; Talib, Zainal Abidin

    2011-03-01

    In this paper, we present thermal conductivity and thermal diffusivity of chromium (Cr) nanoparticle suspended in ethylene glycol at different volume fraction concentrations of nanoparticle. All samples have been prepared using single step method. The thermal conductivity and thermal diffusivity were measured via hot wire-laser beam deflection method. A numerical simulation of the heat conduction equation and probe beam deflection has been performed to determine the effective thermal conductivity and effective thermal diffusivity of Cr nanofluids. By fitting the experimental data to the numerical data, the thermal conductivity and thermal diffusivity of chromium (Cr)-ethylene glycol was obtained. The results also show that the effective thermal conductivity and thermal diffusivity of nanofluids increases with the increasing of nanoparticle volume fraction concentration in base fluid.

  4. Selecting Eco-Friendly Thermal Systems for the “Vittoriale Degli Italiani” Historic Museum Building

    Directory of Open Access Journals (Sweden)

    Davide Astiaso Garcia

    2015-09-01

    Full Text Available Thermal systems installed in museums should guarantee the maintenance of the optimal hygrothermal parameters ranges for the conservation of their collection materials. Considering the preservation of historic buildings, according to their historical and landscaping constraints, not all the thermal system typologies could be installed in these buildings’ typologies. Therefore, the main aim of this paper is to present some indications for the choice of the best thermal system solutions for a considered historic museum building, called Vittoriale degli Italiani, in the north of Italy, taking into account their installation feasibility and their related environmental impacts. The methodology includes a monitoring of the current hygrothermal parameters as well as the assessment of design heat and cooling loads related to the maintenance of the optimal hygrothermal parameters ranges for the conservation of collection materials. In addition, a Life Cycle Assessment (LCA of each selected system typology is considered for highlighting the most eco-friendly solution among the suitable ones. The obtained results highlights the feasible thermal system solutions able to maintain the hygrothermal parameters between the optimal ranges with a lower environmental impact in the Vittoriale degli Italiani historic museum building.

  5. An Empirical Validation of Building Simulation Software for Modelling of Double-Skin Facade (DSF)

    DEFF Research Database (Denmark)

    Larsen, Olena Kalyanova; Heiselberg, Per; Felsmann, Clemens;

    2009-01-01

    Double-skin facade (DSF) buildings are being built as an attractive, innovative and energy efficient solution. Nowadays, several design tools are used for assessment of thermal and energy performance of DSF buildings. Existing design tools are well-suited for performance assessment of conventional...

  6. Occupant Time Period of Thermal Adaption to Change of Outdoor Air Temperature in Naturally Ventilated Buildings

    DEFF Research Database (Denmark)

    liu, weiwei; Wargocki, Pawel; Xiong, Jing

    2014-01-01

    The present work proposed a method to determine time period of thermal adaption of occupants in naturally ventilated building, based on the relationship between their neutral temperatures and running mean outdoor air temperature. Based on the data of the field investigation, the subjects’ time pe...... with the value of the subjects in this study. The comparison shows that the occupants in China had a shorter time period of thermal adaption than European occupants, which means that Chinese occupants can adapt to a new outdoor climate condition faster....... period of thermal adaption was obtained with the proposed method. The result revealed that the subjects needed to take 4.25 days to fully adapt to a step-change in outdoor air temperature. The time period of thermal adaption for the occupants in five European countries was also calculated and compared...

  7. Dynamic Simulation of the Green Roofs Impact on Building Energy Performance, Case Study of Antananarivo, Madagascar

    OpenAIRE

    Hery Tiana Rakotondramiarana; Tojo Fanomezana Ranaivoarisoa; Dominique Morau

    2015-01-01

    Green roofs improve building energy performance and constitute an alternative to sustainable buildings. A green roof model is dynamically coupled with a building thermal model to assess its energy performance that takes into account the indoor air temperature dynamic changes. Under the climate conditions in Antananarivo, we compared green and conventional roofs. The present study shows that green roofs protect the roof structure under extreme temperature and large temperature fluctuations. Fo...

  8. Solar thermal energy / exhaust air heat pump / wood pellet furnace for a sustainable heat supply of low energy buildings in older buildings; Solarthermie / Abluft-Waermepumpe / Pelletofen. Kombisysteme zur nachhaltigen Waermeversorgung von Niedrigenergiehaeusern im Gebaeudebestand

    Energy Technology Data Exchange (ETDEWEB)

    Diefenbach, Nikolaus; Born, Rolf [Institut Wohnen und Umwelt GmbH, Darmstadt (Germany); Staerz, Norbert [Ingenieurbuero inPlan, Pfungstadt (Germany)

    2009-11-13

    The research project under consideration reports on combination systems for a sustainable heat supply for low-energy buildings in older building. For this, a central and decentralized system configuration consisting of solar thermal energy, exhaust air heat pump and wood pellet furnace are presented. Solutions for an interaction of these three heat suppliers in one plant are designated regarding the control strategy. The fundamentals of the computerized simulations for the central and decentralized system are presented. A cost estimate with both variants of the combination system as well as a comparison with conventional energy-saving heat supply systems follow.

  9. Physical and JIT Model Based Hybrid Modeling Approach for Building Thermal Load Prediction

    Science.gov (United States)

    Iino, Yutaka; Murai, Masahiko; Murayama, Dai; Motoyama, Ichiro

    Energy conservation in building fields is one of the key issues in environmental point of view as well as that of industrial, transportation and residential fields. The half of the total energy consumption in a building is occupied by HVAC (Heating, Ventilating and Air Conditioning) systems. In order to realize energy conservation of HVAC system, a thermal load prediction model for building is required. This paper propose a hybrid modeling approach with physical and Just-in-Time (JIT) model for building thermal load prediction. The proposed method has features and benefits such as, (1) it is applicable to the case in which past operation data for load prediction model learning is poor, (2) it has a self checking function, which always supervises if the data driven load prediction and the physical based one are consistent or not, so it can find if something is wrong in load prediction procedure, (3) it has ability to adjust load prediction in real-time against sudden change of model parameters and environmental conditions. The proposed method is evaluated with real operation data of an existing building, and the improvement of load prediction performance is illustrated.

  10. Molecular dynamics simulations of thermal effects in nanometric cutting process

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Understanding the basic action of how material removing in nanoscale is a critical issue of producing well-formed components.In order to clarify thermal effects on material removal at atomic level,molecular dynamics(MD)simulations of nanometric cutting of mono-crystalline copper are performed with Morse,EAM and Tersoff potential.The effects of cutting speed on temperature distribution are investigated.The simulation results demonstrate that the temperature distribution shows a roughly concentric shape around shear zone and a steep temperature gradient lies in diamond tool,a relative high temperature is located in shear zone and machined surface,but the highest temperature is found in chip.At a high cutting speed mode,the atoms in shear zone with high temperature implies a large stress is built up in a local region.

  11. Investigation on Thermal Properties of Composite of Rice Husk, Corncob and Baggasse for Building Thermal Insulation

    Directory of Open Access Journals (Sweden)

    Kyauta E.E. Dauda D.M

    2014-12-01

    Full Text Available The thermal properties of some Agricultural waste ( Rice Husk, Bagasse and Corncob was investigated with the purpose of determining their use as insulators. Using varied composite percentages of each sample wastes at increasing and decreasing quantities to determine best mixtures has assisted in accurate recommendation. The work has explored the potentials for using composite samples of Rice Husk, Bagasse and Corncob as materials for thermal insulation, a solution which offers a reduction in resource use, promote recycle of the wastes, less dependent on toxic chemical types in wood/cellulose based insulators, in addition to reducing energy consumed by altering internal air conditions.The criteria for evaluation includes experimental determination of Thermal Conductivities and Specific Heat Capacities for composites samples and other dependable properties.The results from evaluations have identified that sample G with 0.231Wm-1 k -1 and 22.114m-1 is the best mixed with more rice husk and considerable percentage of bagasse to less percentage of corncob

  12. The estimation of enclosing structures edge zones influence on thermal performance and energy efficiency of buildings (rus

    Directory of Open Access Journals (Sweden)

    Korniyenko S.V.

    2011-12-01

    Full Text Available One of priority directions in modern building is maintenance of energy efficiency of buildings and constructions. This problem can be realized by perfection of architectural, constructive and technical decisions. The particular interest is represented by an influence estimation of temperature and moisture mode of enclosing structures on a thermal performance and energy efficiency of buildings. The analysis of the data available in the literature has shown absence of effective calculation methods of temperature and moisture mode in edge zones of enclosing structures that complicates the decision of this problem.The purpose of the given work is an estimation of edge zones influence on a thermal performance and energy efficiency of buildings. The design procedure of energy parameters of a building for the heating period, realized in the computer program is developed. The given technique allows settling an invoice power inputs on heating, hot water supply, an electrical supply. Power inputs on heating include conduction heat-losses through an envelope of a building taking into account edge zones, ventilation heat-losses and leakage air (infiltration, internal household thermal emissions, heat-receipt from solar radiation. On an example it is shown that the account of edge zones raises conduction heat-losses through an envelope of a building on 37 %, the expense of thermal energy on building heating on 32 %, and the expense thermal and electric energy on 13 %. Consequently, thermal and moisture mode in edge zones of enclosing structures makes essential impact on building power consumption. Perfection of the constructive decision leads to decrease of transmission heat-losses through an envelope of a building on 29 %, the expense of thermal energy on building heating on 25 %, the expense of thermal and electric energy on 10 %. Thus, perfection of edge zones of enclosing structures has high potential of energy efficiency.

  13. Simulation Tests in Whole Building Heat and Moisture Transfer

    DEFF Research Database (Denmark)

    Rode, Carsten; Peuhkuri, Ruut Hannele; Woloszyn, Monika

    2006-01-01

    An important part of the International Energy Agency project, ECBCS, Annex 41 is about modelling the integral heat, air and moisture transfer processes that take place in “whole buildings”. Such modelling deals with all most relevant elements of buildings: The indoor air, the building envelope...

  14. Thermal activation of building construction: possibility also in building reconstructions; Thermische Bauteilaktivierung auch bei Bauwerksanierungen

    Energy Technology Data Exchange (ETDEWEB)

    Glueck, B. [TGA Joessnitz (Plauen) (Germany)

    2002-04-01

    The thermal activation of concrete ceilings, also concrete called core activation, is getting a large spread in the last years. Since the water tubing registers must be brought in during the concreting process, this technology is not applicable in the case of reconstructions. To be able to use the energetic advantages - which occur with the use of water temperatures near room temperature, also within the construction area, there is a set of suggestions. A version, which includes even the storage in the available concrete ceilings, is examined in consideration of is efficiency. (orig.) [German] Die thermische Bauteilaktivierung von Massivdecken - auch Betonkernaktivierung genannt - hat in den letzten Jahren eine grosse Verbreitung erfahren. Da die wasserdurchflossenen Rohrregister waehrend des Betoniervorgangs eingebracht werden muessen, ist diese Technologie im Sanierungsfall nicht anwendbar. Um die energetischen Vorteile - die beim Einsatz von raumnahen Wassertemperaturen auftreten - auch im Sanierungsbereich nutzbar zu machen, gibt es eine Reihe von Vorschlaegen. Eine Variante, die sogar die Speicherung von vorhandenen Massivdecken einbezieht, wird auf ihre Leistungsfaehigkeit untersucht. (orig.)

  15. Impacts of dynamic interactions on the predicted thermal performance of earth–air heat exchangers for preheating, cooling and ventilation of buildings

    OpenAIRE

    Gan, Guohui

    2015-01-01

    Earth–air tunnel ventilation is an energy efficient ventilation technique that makes use of relatively stable soil temperature in shallow ground for preheating and cooling of supply air to a building. During operation, an earth–air heat exchanger interacts with the soil and atmosphere and the performance varies with the soil and atmospheric conditions. A computer program has been developed for modelling of coupled heat and moisture transfer in soil and for simulation of the dynamic thermal pe...

  16. On the impact of building attenuation models in urban VANET simulations

    OpenAIRE

    Luis Urquiza-Aguiar; Carolina Tripp-Barba; José Estrada-Jiménez; Mónica Aguilar Igartua

    2015-01-01

    Buildings are important elements of cities for VANETs, since these obstacles may attenuate communications between vehicles. Consequently, the impact of buildings has to be considered as part of the attenuation model in VANET simulations of urban scenarios. However, the more elaborated the model, the more information needs to be processed during the simulation, which implies longer processing times. This complexity in simulations is not always worth it, because simplified channel models occasi...

  17. Thermal behavior simulation of Ni/MH battery

    Institute of Scientific and Technical Information of China (English)

    LI DaHe; YANG Kai; CHEN Shi; WU Feng

    2009-01-01

    Thermal behavior of overcharged Ni/MH battery is studied with microcalorimeter. The battery Is in-stalled in a special device in a microcslorimeter with a quartz frequency thermometer. Quantity of heat and heat capacity of the battery charged at different state of charge (SOC) st different rates are meas-ured by the microcalorimeter. Based on a series of aseumputions, heat transfer equation is set up. Ex-pression of heat generation is attained by curve fitting instead of theoretical calculation. Thermal model is used to simulate thermal behavior of the battery in charging period, results of calculation and expe-riment match very well. The temperature distribution is non-uniform because the poor conductivity limits the heat transfer during charging process. It is difficult to greatly improve the heat conductivity of the battery because it is related to materials inside the battery including electrodes, separators and so on. Therefore, high rate charge should be avoided in actual use. It may cause some damage to the battery.

  18. Simulation Technology of Environmental Impacts by Zero-energy Residential Buildings Based on Emergy Analysis Method

    Institute of Scientific and Technical Information of China (English)

    Hong Zhou; XiaoLong Xue; WangShu Yang

    2014-01-01

    This paper presents a simulation technology of environmental impact for the building. By emergy analysis method, emergy costs of building( or construction engineering) can be calculated in the life cycle. It includes the engineering cost, environmental cost and social cost of building. Through integrating GIS technology with multi-agent technology, life cycle substance and energy metabolism of building ( construction engineering) can be simulated and their environmental influence can be dynamically displayed. Based on the case study of entries works ‘Sunny Inside’ by Xiamen University in 2013 China International Solar Decathlon Competition, we discovered the changing pattern of surrounding environmental impact from waste streams of the zero-energy building and ordinary construction. The simulation results verified and showed the Odum principles of maximum power. This paper provides a new research perspective and integration approach for the environmental impact assessment in building and construction engineering. The result will help decision-making in design and construction engineering scheme.

  19. Parabolic Trough Photovoltaic/Thermal Collectors: Design and Simulation Model

    Directory of Open Access Journals (Sweden)

    Laura Vanoli

    2012-10-01

    Full Text Available This paper presents a design procedure and a simulation model of a novel concentrating PVT collector. The layout of the PVT system under investigation was derived from a prototype recently presented in literature and commercially available. The prototype consisted in a parabolic trough concentrator and a linear triangular receiver. In that prototype, the bottom surfaces of the receiver are equipped with mono-crystalline silicon cells whereas the top surface is covered by an absorbing surface. The aperture area of the parabola was covered by a glass in order to improve the thermal efficiency of the system. In the modified version of the collector considered in this paper, two changes are implemented: the cover glass was eliminated and the mono-crystalline silicon cells were replaced by triple-junction cells. In order to analyze PVT performance, a detailed mathematical model was implemented. This model is based on zero-dimensional energy balances. The simulation model calculates the temperatures of the main components of the system and the main energy flows Results showed that the performance of the system is excellent even when the fluid temperature is very high (>100 °C. Conversely, both electrical and thermal efficiencies dramatically decrease when the incident beam radiation decreases.

  20. Study of temperature dependence of thermal conductivity in cross-linked epoxies using molecular dynamics simulations with long range interactions

    International Nuclear Information System (INIS)

    In this work, we demonstrate the use of the Green–Kubo integral of the heat flux autocorrelation function, incorporating long-range corrections to model the thermal conductivity versus temperature relationship of cross-linked polymers. The simulations were performed on a cross-linked epoxy made from DGEBA and a curing agent (diamino diphenyl sulfone) using a consistent valence force field (CVFF). A dendrimeric approach was utilized for building equilibrated cross-linked structures that allowed replication of the experimental dilatometric curve for the epoxy system. We demonstrate that the inclusion of a long-range correction within the Ewald/PPPM approach brings the results close to experimentally measured conductivity within an error of 10% while providing a good prediction of the relationship of thermal conductivity versus temperature. This method shows significant promise towards the computation of thermal conductivity from simulations even before synthesis of the polymer for purposes of materials by design. (paper)

  1. Application of Nanotechnology-Based Thermal Insulation Materials in Building Construction

    Science.gov (United States)

    Bozsaky, David

    2016-03-01

    Nanotechnology-based materials have previously been used by space research, pharmaceuticals and electronics, but in the last decade several nanotechnology-based thermal insulation materials have appeared in building industry. Nowadays they only feature in a narrow range of practice, but they offer many potential applications. These options are unknown to most architects, who may simply be afraid of these materials owing to the incomplete and often contradictory special literature. Therefore, they are distrustful and prefer to apply the usual and conventional technologies. This article is intended to provide basic information about nanotechnology-based thermal insulation materials for designers. It describes their most important material properties, functional principles, applications, and potential usage options in building construction.

  2. Use of infrared thermography in detection, remediation, and commissioning of thermal comfort problems in office buildings

    Science.gov (United States)

    Colantonio, Antonio

    2001-03-01

    Thermal comfort complaints within work places are one of the leading causes of workforce productivity loss within office environments. Generally, mechanical systems are relied on to provide adequate indoor environments. In many situations, these systems cannot provide suitable work environments due to unacceptable asymmetrical radiant temperature conditions found in exterior zones of building interiors. Public Works and Government Services Canada (PWGSC) has developed methodologies using infrared technology to assist building and office managers in reducing thermal comfort complaints and improve workforce productivity. Detection, verification, remediation and commissioning of solutions are easily and effectively carried out with the assistance of infrared radiometers and proper inspection and analysis procedures. This paper will outline two case studies and detail methodologies used in each case.

  3. Thermal and airflow prediction in buildings by associating models with different levels of details within an object-oriented simulation environment; Prediction des performances thermo-aerauliques des batiments par association de modeles de differents niveaux de finesse au sein d'un environnement oriente objet

    Energy Technology Data Exchange (ETDEWEB)

    Mora, L.

    2003-09-01

    The design of innovative HVAC systems, as well as the evaluation of the comfort of occupants requires a detailed estimation of airflows and heat transfers within building zones. Zonal and CFD methods can in principal provide such details, but in practice they are difficult to apply to study a whole building over long periods of time. In this study, we propose a new simulation platform based on the object oriented simulation environment SPARK to treat most of building zones using the nodal approach. This modeling method considers each zone as a fully and instantaneously well mixed volume. In this case, each zone can be characterized by a unique computational node where temperature, pressure and concentration are determined. Then, some specific rooms are studied with more details. In order to see the impact of these details on the entire building model, we propose different coupling methods depending on models associations between the nodal approach, and zonal or CFD room models. After a brief presentation of the different modeling methods used in this study, we attempt to demonstrate the interest to use one method instead of another depending on the room characteristics or the modeler's objectives. We then present the developed platform in which we solve both nodal and zonal models, and we couple detailed room models with the first method. Finally, a few applications demonstrate some capabilities of the developed platform to not only adjust the level of detail for each room model, but also propose new ways of research. In fact, the last application shows a new coupling method between zonal and CFD methods. In this approach, the first method acquires the airflow structure from results obtained using a CFD model in the room. Consequently, the developed platform has numerous applications, to study the dynamics of heat and mass transfers in buildings as well as in their immediate surroundings. (author)

  4. Effect of Thermal Bridges in Insulated Walls on Air-Conditioning Loads Using Whole Building Energy Analysis

    OpenAIRE

    Mohamed F. Zedan; Sami Al-Sanea; Abdulaziz Al-Mujahid; Zeyad Al-Suhaibani

    2016-01-01

    Thermal bridges in building walls are usually caused by mortar joints between insulated building blocks and by the presence of concrete columns and beams within the building envelope. These bridges create an easy path for heat transmission and therefore increase air-conditioning loads. In this study, the effects of mortar joints only on cooling and heating loads in a typical two-story villa in Riyadh are investigated using whole building energy analysis. All loads found in the villa, which br...

  5. Computational method for simulation of thermal load distribution in a lithographic lens.

    Science.gov (United States)

    Yu, Xinfeng; Ni, Mingyang; Rui, Dawei; Qu, Yi; Zhang, Wei

    2016-05-20

    As a crucial step for thermal aberration prediction, thermal simulation is an effective way to acquire the temperature distribution of lenses. In the case of rigorous thermal simulation with the finite volume method, the amount of absorbed energy and its distribution within lens elements should be provided to guarantee simulation accuracy. In this paper, a computational method for simulation of thermal load distribution concerning lens material absorption was proposed based on light intensity of lens elements' surfaces. An algorithm for the verification of the method was also introduced, and the results showed that the method presented in this paper is an effective solution for thermal load distribution in a lithographic lens. PMID:27411148

  6. A Temperature-Dependent Thermal Model of IGBT Modules Suitable for Circuit-Level Simulations

    DEFF Research Database (Denmark)

    Wu, Rui; Wang, Huai; Pedersen, Kristian Bonderup;

    2016-01-01

    A basic challenge in the IGBT transient simulation study is to obtain the realistic junction temperature, which demands not only accurate electrical simulations but also precise thermal impedance. This paper proposed a transient thermal model for IGBT junction temperature simulations during short...... circuits or overloads. The updated Cauer thermal model with varying thermal parameters is obtained by means of FEM thermal simulations with temperature-dependent physical parameters. The proposed method is applied to a case study of a 1700 V/1000 A IGBT module. Furthermore, a testing setup is built up...

  7. Application of Nanotechnology-Based Thermal Insulation Materials in Building Construction

    OpenAIRE

    Bozsaky David

    2016-01-01

    Nanotechnology-based materials have previously been used by space research, pharmaceuticals and electronics, but in the last decade several nanotechnology-based thermal insulation materials have appeared in building industry. Nowadays they only feature in a narrow range of practice, but they offer many potential applications. These options are unknown to most architects, who may simply be afraid of these materials owing to the incomplete and often contradictory special literature. Therefore, ...

  8. Energy system investment model incorporating heat pumps with thermal storage in buildings and buffer tanks

    International Nuclear Information System (INIS)

    Individual compression heat pumps constitute a potentially valuable resource in supporting wind power integration due to their economic competitiveness and possibilities for flexible operation. When analysing the system benefits of flexible heat pump operation, effects on investments should be taken into account. In this study, we present a model that facilitates analysing individual heat pumps and complementing heat storages in integration with the energy system, while optimising both investments and operation. The model incorporates thermal building dynamics and covers various heat storage options: passive heat storage in the building structure via radiator heating, active heat storage in concrete floors via floor heating, and use of thermal storage tanks for space heating and hot water. It is shown that the model is well qualified for analysing possibilities and system benefits of operating heat pumps flexibly. This includes prioritising heat pump operation for hours with low marginal electricity production costs, and peak load shaving resulting in a reduced need for peak and reserve capacity investments. - Highlights: • Model optimising heat pumps and heat storages in integration with the energy system. • Optimisation of both energy system investments and operation. • Heat storage in building structure and thermal storage tanks included. • Model well qualified for analysing system benefits of flexible heat pump operation. • Covers peak load shaving and operation prioritised for low electricity prices

  9. Building America Best Practices Series, Volume 6: High-Performance Home Technologies: Solar Thermal & Photovoltaic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, Michael C.; Gilbride, Theresa L.; Ruiz, Kathleen A.; Steward, Heidi E.; Love, Pat M.

    2007-06-04

    This guide is was written by PNNL for the US Department of Energy's Building America program to provide information for residential production builders interested in building near zero energy homes. The guide provides indepth descriptions of various roof-top photovoltaic power generating systems for homes. The guide also provides extensive information on various designs of solar thermal water heating systems for homes. The guide also provides construction company owners and managers with an understanding of how solar technologies can be added to their homes in a way that is cost effective, practical, and marketable. Twelve case studies provide examples of production builders across the United States who are building energy-efficient homes with photovoltaic or solar water heating systems.

  10. A Building Energy Efficiency Optimization Method by Evaluating the Effective Thermal Zones Occupancy

    Directory of Open Access Journals (Sweden)

    Franco Cotana

    2012-12-01

    Full Text Available Building energy efficiency is strongly linked to the operations and control systems, together with the integrated performance of passive and active systems. In new high quality buildings in particular, where these two latter aspects have been already implemented at the design stage, users’ perspective, obtained through post-occupancy assessment, has to be considered to reduce whole energy requirement during service life. This research presents an innovative and low-cost methodology to reduce buildings’ energy requirements through post-occupancy assessment and optimization of energy operations using effective users’ attitudes and requirements as feedback. As a meaningful example, the proposed method is applied to a multipurpose building located in New York City, NY, USA, where real occupancy conditions are assessed. The effectiveness of the method is tested through dynamic simulations using a numerical model of the case study, calibrated through real monitoring data collected on the building. Results show that, for the chosen case study, the method provides optimized building energy operations which allow a reduction of primary energy requirements for HVAC, lighting, room-electricity, and auxiliary supply by about 21%. This paper shows that the proposed strategy represents an effective way to reduce buildings’ energy waste, in particular in those complex and high-efficiency buildings that are not performing as well as expected during the concept-design-commissioning stage, in particular due to the lack of feedback after the building handover.

  11. Molecular Dynamics Simulation of Thermal Conductivity in Si-Ge Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    HUANG Xiao-Peng; HUAI Xiu-Lan

    2008-01-01

    @@ Thermal conductivity of nanocomposites is calculated by molecular dynamics (MD) simulation. The effect of size on thermal conductivity of nanowire composites and the temperature profiles are studied. The results indicate that the thermal conductivity of nanowire composites could be much lower than alloy value; the thermal conductivity is slightly dependent on temperature except at very low temperature.

  12. Thermal properties of a new ecological building material / Granular cork embedded in white cement

    Directory of Open Access Journals (Sweden)

    Cherki Abou-bakr

    2014-04-01

    Full Text Available Cork, natural and renewable product, has thermal and acoustic properties very interesting because of its microstructure and porosity representing a significant portion of its apparent volume; it’s coming from Moroccan Maamora’s forest. This work is a contribution to understand the thermal behaviour of the composite material based on granular cork embedded in white cement. An experimental investigation of its thermal properties was mainly performed using the asymmetrical device of transient Hot Plate method. The effect of granular cork size on the thermal properties of the mixture was studied. The experimental study of this sustainable material aims to characterize its thermal properties and then compare them with those of white cement without cork for motivate the proposal that this composite material will be used as walls insulator. A comparison of the energy performances of the composite material and white cement was made; it allows deducing a very interesting energy gain. The findings of the experiments indicate that the composite is better than white cement in term of thermal insulation, energy storage capacity and lightness. So, it can be used to realize the internal walls insulation. Its utilization should contribute to the improvement of the energy efficiency in building especially that this is a mixture based on a sustainable and renewable material.

  13. Hydro-thermal experiments and simulations within a granitic fracture

    Science.gov (United States)

    Neuville, Amélie; Flekkøy, Eirik; Jørgen Måløy, Knut; Toussaint, Renaud; Galland, Olivier

    2013-04-01

    The porous medium that we consider is a fracture with impermeable walls that have a complex topography. Our study aims at addressing the heat and mass transport which occurs during the injection of cold water into a fracture, initially filled with warm water and embedded in a warm rock. The characterization of such transfers is relevant to, for instance, hydrothermal circulations occurring at depth, or use of temperature measurements as a tracer of flow pathways. The fluid-rock interface separates exclusively-diffusive from advecto-diffusive processes where the water flows, and the heat diffusion is different in the water and rock. We look at the shape of the isotherm lines (in two dimensions) or surfaces (in three dimensions -- 3D) through time, until steady state is reached. We have both numerical and experimental approaches. The numerical simulations are done with a coupled lattice Boltzmann method that solves both the complete Navier-Stokes and advection-diffusion equations in 3D. The experimental setup has been developed in order to adjust the scaling of our simulations and further investigate the complexity of the hydro-thermal exchange. In this setup, an infrared camera and thermistors are used to monitor the temperature in space and time. Water is injected through a partly natural rough fracture: the bottom part is a granitic bloc with a rough wall, and the top part is a flat layer which is transparent in the infrared range. The surface of the granitic bloc has been digitized using a photogrammetry software (MicMac, developed by the French Institut Géographique National). This digitized surface is then transformed into a 3D mask showing void spaces and rock (digitized porous medium), and is used for the 3D hydro-thermal simulations. We will first present a numerical simulation where the geometry of the fracture consists of flat parallel walls perturbed by a single cavity. Then we will present experimental observations of the temperature done using a

  14. Rocks, Clays, Water, and Salts: Highly Durable, Infinitely Rechargeable, Eminently Controllable Thermal Batteries for Buildings

    Directory of Open Access Journals (Sweden)

    Alan W. Rempel

    2013-01-01

    Full Text Available Materials that store the energy of warm days, to return that heat during cool nights, have been fundamental to vernacular building since ancient times. Although building with thermally rechargeable materials became a niche pursuit with the advent of fossil fuel-based heating and cooling, energy and climate change concerns have sparked new enthusiasm for these substances of high heat capacity and moderate thermal conductivity: stone, adobe, rammed earth, brick, water, concrete, and more recently, phase-change materials. While broadly similar, these substances absorb and release heat in unique patterns characteristic of their mineralogies, densities, fluidities, emissivities, and latent heats of fusion. Current architectural practice, however, shows little awareness of these differences and the resulting potential to match materials to desired thermal performance. This investigation explores that potential, illustrating the correspondence between physical parameters and thermal storage-and-release patterns in direct-, indirect-, and isolated-gain passive solar configurations. Focusing on heating applications, results demonstrate the superiority of water walls for daytime warmth, the tunability of granite and concrete for evening warmth, and the exceptional ability of phase-change materials to sustain near-constant heat delivery throughout the night.

  15. Thermal Energy Storage for Building Load Management: Application to Electrically Heated Floor

    Directory of Open Access Journals (Sweden)

    Hélène Thieblemont

    2016-07-01

    Full Text Available In cold climates, electrical power demand for space conditioning becomes a critical issue for utility companies during certain periods of the day. Shifting a portion or all of it to off-peak periods can help reduce peak demand and reduce stress on the electrical grid. Sensible thermal energy storage (TES systems, and particularly electrically heated floors (EHF, can store thermal energy in buildings during the off-peak periods and release it during the peak periods while maintaining occupants’ thermal comfort. However, choosing the type of storage system and/or its configuration may be difficult. In this paper, the performance of an EHF for load management is studied. First, a methodology is developed to integrate EHF in TRNSYS program in order to investigate the impact of floor assembly on the EHF performance. Then, the thermal comfort (TC of the night-running EHF is studied. Finally, indicators are defined, allowing the comparison of different EHF. Results show that an EHF is able to shift 84% of building loads to the night while maintaining acceptable TC in cold climate. Moreover, this system is able to provide savings for the customer and supplier if there is a significant difference between off-peak and peak period electricity prices.

  16. Fuzzy Evaluation of Thermal Comfort in Naturally Ventilated Residential Buildings in China

    Institute of Scientific and Technical Information of China (English)

    WANG Yi; NIU Tian-cai; LIU Jia-ping; XIAO Yong-qiang

    2009-01-01

    In order to assess the differences between the human body thermal sensation in naturally ventilat-ed space and that in air-conditioned space,the fuzzy evaluation model was adopted in the research of thermal sensation in naturally ventilated space.Based on the questionnaires and field measurements,the membership functions were presented by the statistic of the covering frequency to the fuzzy subset.Dry-bulb temperature was taken as the only independent variable for membership functions.The maximum values of membership grades are all at 0.5 or so, which is a distinction character on thermal comfort of naturally ventihted space.By the cal-culating resultS of membership grades value to different fuzzy evaluation subsets,the Predicted Mean Vote (PMV)was obtained.Furthermore,energy coefficient(Ea) was introduced to calculate the energy consump-tion,and the prediction methods of residential building energy consumption were also discussed.Finally,the importance of evaluation model of thermal sense is shown through the energy consumption prediction in a specificresidential building.

  17. Building Energy Storage Panel Based on Paraffin/Expanded Perlite: Preparation and Thermal Performance Study

    Directory of Open Access Journals (Sweden)

    Xiangfei Kong

    2016-01-01

    Full Text Available This study is focused on the preparation and performance of a building energy storage panel (BESP. The BESP was fabricated through a mold pressing method based on phase change material particle (PCMP, which was prepared in two steps: vacuum absorption and surface film coating. Firstly, phase change material (PCM was incorporated into expanded perlite (EP through a vacuum absorption method to obtain composite PCM; secondly, the composite PCM was immersed into the mixture of colloidal silica and organic acrylate, and then it was taken out and dried naturally. A series of experiments, including differential scanning calorimeter (DSC, scanning electron microscope (SEM, best matching test, and durability test, have been conducted to characterize and analyze the thermophysical property and reliability of PCMP. Additionally, the thermal performance of BESP was studied through a dynamic thermal property test. The results have showed that: (1 the surface film coating procedure can effectively solve the leakage problem of composite phase change material prepared by vacuum impregnation; (2 the optimum adsorption ratio for paraffin and EP was 52.5:47.5 in mass fraction, and the PCMP has good thermal properties, stability, and durability; and (3 in the process of dynamic thermal performance test, BESP have low temperature variation, significant temperature lagging, and large heat storage ability, which indicated the potential of BESP in the application of building energy efficiency.

  18. The Implementation of Industry Foundation Classes in Simulation Tools for the Building Industry

    Energy Technology Data Exchange (ETDEWEB)

    Bazjanac, Vladimir; Crawley, Drury B.

    1997-06-01

    Industry Foundation Classes (IFC) provide an environment of interoperability among IFC-compliant software applications in the architecture, engineering, construction, and facilities management (AEC/FM) industry. They allow building simulation software to automatically acquire building geometry and other building data from project models created with IFC compliant CAD software. They also facilitate direct exchange of input and output data with other simulation software. This paper discusses how simulation software can be made compliant with version 1.5 of the IFC. It also describes the immediate plans for expansion of IFC and the process of definition and addition of new classes to the model.

  19. Design and thermal performance of a passive cooled building for the semiarid climate of India

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, A.; Nayak, J.K.; Sodha, M.S.; Tiwari, G.N.

    1984-01-01

    This communication presents design and thermal performance of a hostel building using passive cooling approaches at Jodhpur in India. Jodhpur is a representative of the semiarid climate in India where, in summer, on average, ambient air temperature is 34.4/sup 0/C, relative humidity is 28% and substantial wind in the southeast direction is present. A thermal model, based on Fourier series in time) expansions of solar insolation and ambient air temperature, is developed and applied to study the effectiveness of various cooling approaches such as a wind tower, a desert cooling fan and evaporative cooling on the roof. Numerical calculations show that the best cooling occurs in the rooms which are partially underground and when the roof is treated by evaporative cooling. The living room becomes thermally very comfortable when roof evaporative cooling is used along with a desert cooling fan.

  20. Simulation and parametric optimisation of thermal power plant cycles

    Directory of Open Access Journals (Sweden)

    P. Ravindra Kumar

    2016-09-01

    Full Text Available The objective of the paper is to analyse parametric studies and optimum steam extraction pressures of three different (subcritical, supercritical and ultra-supercritical coal fired power plant cycles at a particular main steam temperature of 600 °C by keeping the reheat temperature at 537 °C and condenser pressure at 0.09 bar as constant. In order to maximize the heat rate gain possible with supercritical and ultra-supercritical steam conditions, eight stages of feed water heater arrangement with single reheater is considered. The system is optimized in such a way that the percentage exergetic losses are reduced for the increase of the exergetic efficiency and higher fuel utilization. The plant cycles are simulated and optimized by using Cycle Tempo 5.0 simulation software tool. From the simulation study, it is observed that the thermal efficiency of the three different power plant cycles obtained as 41.40, 42.48 and 43.03%, respectively. The specific coal consumption for three different power plant cycles are 0.56, 0.55 and 0.54 Tonnes/MWh. The improvement in feed water temperatures at the inlet of steam generator of respective cycles are 291, 305 and 316 °C.

  1. The Climate Analysis Seoul (CAS) simulation for thermal characteristics in different urban locations in Seoul, Korea

    Science.gov (United States)

    Lee, Young-Gon; Lee, Jisu; Kim, Baek-Jo

    2016-04-01

    The Climate Analysis Seoul (CAS) being tailored for simulating detailed climate was applied to investigate the temperature distribution around the Seonjeongneung Royal Tombs that includes forest and grassland and in the surrounding high-density buildings in Seoul, Korea for a hot summer days of August 6-7, 2015. In this study, we used the digitalized topographical and land-use data of the 5 m resolution and wind and air temperature fields of 100 m resolution produced by the numerical model MetPhoMod (MPM), part of the CAS for the area of interest with an area of 25,000,000 m2. The difference of the temperatures compared with the representative meteorological station of Seoul was analyzed by considering the presence or absence of the Seonjeongneung Royal Tombs. For the case of heat wave issued in Seoul from August 6th, 06 LST to 7th, 18 LST, 2015, the simulation results presented that averaged temperatures in the green area were 2 °C lower than the one of the standard weather station, whereas they showed 1.5 °C higher when the green area was replaced with the building area. From this simulation result, we can suggest that the green area has a temperature reduction effect of 1-3 °C and its influence can be extended up to 150 m from the boundary of the green area. This fact reconfirms that the urban green area generates a micro-scale cool-island effect and this local phenomenon can reduce heat stress produced by surplus thermal sources of the surrounding buildings and paved roads during the hot summer days. Key words: Climate Analysis Seoul (CAS), Urban Green Area, Cool-Island Effect

  2. Monte Carlo simulation of positronium thermalization in gases

    Directory of Open Access Journals (Sweden)

    Marjanović Srđan D.

    2010-01-01

    Full Text Available In this paper we present the results of Monte Carlo simulations of positronium (Ps swarm thermalization in helium (He and water vapour. We have investigated the temporal evolution of energy and spatial parameters of the swarm and their sensitivity to the shape of the cross-section and the initial energy distribution. Positron anihilation spectroscopy (PAS and positron emission tomography (PET are techniques that depend on anihilation of positronium in materials and tissue. The results obtained point that the Monte Carlo technique shows good agreement with experimental results and is capable of accurately describing the behaviour of Ps particles including the energy, particle lifetime and the moment and location of the anihilation.

  3. Absolute rate of thermal desorption from first-principles simulation

    International Nuclear Information System (INIS)

    We present a technique for computing by first-principles simulation the absolute desorption rate γ of adsorbate molecules from a surface for any coverage and temperature. The technique is valid when the thermal equilibration rate on the surface is faster than γ, and is based on an exact expression for γ in terms of the difference of non-configurational chemical potentials of gas-phase and adsorbed molecules. This difference is expressed in terms of a potential of mean force, which is computed by constrained first-principles molecular dynamics. The technique is applied to D2O on the MgO(001) surface at low coverage, using the generalized gradient approximation (GGA) for exchange-correlation energy. Comparisons with experimental temperature programmed desorption data allow an assessment of the accuracy of the GGA for the adsorption of D2O on MgO(001). (letter to the editor)

  4. Collider bypass diode thermal simulations and measurements for the SSCL

    Energy Technology Data Exchange (ETDEWEB)

    Rostamzadeh, C.; Tool, G.

    1993-05-01

    Warm bypass diodes will be used as a component of a quench protection system to bypass an exponentially decaying current of 36 sec. time constant and peak current of 7000 A. Temperature excursions due to approximately 252 Kilo Ampere Sec. are studied using ANSYS, a finite element analysis program. A parabolic current waveform of similar energy but higher MIITs (1058 MIIT) was applied to the bypass circuit and temperature excursion was measured at various locations. The procedure of current waveform generation and thermal measurements is illustrated in this paper. A comparison of simulation technique with actual measurements confirms the accuracy of the bypass diode assembly model. This assembly is installed at the SSC half-cell string test facility and results are extremely encouraging.

  5. Nuclear Thermal Rocket Element Environmental Simulator (NTREES) Upgrade Activities

    Science.gov (United States)

    Emrich, William

    2013-01-01

    A key technology element in Nuclear Thermal Propulsion is the development of fuel materials and components which can withstand extremely high temperatures while being exposed to flowing hydrogen. NTREES provides a cost effective method for rapidly screening of candidate fuel components with regard to their viability for use in NTR systems. The NTREES is designed to mimic the conditions (minus the radiation) to which nuclear rocket fuel elements and other components would be subjected to during reactor operation. The NTREES consists of a water cooled ASME code stamped pressure vessel and its associated control hardware and instrumentation coupled with inductive heaters to simulate the heat provided by the fission process. The NTREES has been designed to safely allow hydrogen gas to be injected into internal flow passages of an inductively heated test article mounted in the chamber.

  6. Advanced wellbore thermal simulator GEOTEMP2 user manual

    Energy Technology Data Exchange (ETDEWEB)

    Mondy, L.A.; Duda, L.E.

    1984-11-01

    GEOTEMP2 is a wellbore thermal simulator computer code designed for geothermal drilling and production applications. The code treats natural and forced convection and conduction within the wellbore and heat conduction within the surrounding rock matrix. A variety of well operations can be modeled including injection, production, forward, and reverse circulation with gas or liquid, gas or liquid drilling, and two-phase steam injection and production. Well completion with several different casing sizes and cement intervals can be modeled. The code allows variables suchas flow rate to change with time enabling a realistic treatment of well operations. This user manual describes the input required to properly operate the code. Ten sample problems are included which illustrate all the code options. Complete listings of the code and the output of each sample problem are provided.

  7. The Simulation and Mapping of Building Performance Indicators based on European Weather Stations

    CERN Document Server

    van Schijndel, A W M

    2012-01-01

    Due to the climate change debate, a lot of research and maps of external climate parameters are available. However, maps of indoor climate performance parameters are still lacking. This paper presents a methodology for obtaining maps of performances of similar buildings that are virtually spread over whole Europe. The produced maps are useful for analyzing regional climate influence on building performance indicators such as energy use and indoor climate. This is shown using the Bestest building as a reference benchmark. An important application of the mapping tool is the visualization of potential building measures over the EU. Also the performances of single building components can be simulated and mapped. It is concluded that the presented method is efficient as it takes less than 15 minutes to simulate and produce the maps on a 2.6GHz/4GB computer. Moreover, the approach is applicable for any type of building.

  8. Space nuclear reactor SP-100 thermal-hydraulic simulation

    International Nuclear Information System (INIS)

    Since 1983 it has been under development in the USA the project SP-100 of space nuclear reactors for electric generation in a range of 100 to 1000 KWe. In this project the heat is generated at the core of a fast compact liquid lithium refrigerated reactor. Thermoelectric converters produce direct current electric energy and the primary and secondary loops flow is controlled by electromagnetic thermoelectric pumps (EMTE). In this work it is studied a system with a fast nuclear reactor, with similar characteristics to the SP-100, aiming at generating high electric power in space for a future application on the TERRA (Advanced Fast Reactor Technology) Project of IEAv (Institute for Advanced Studies). It will be presented the working principles, basic structure and operation characteristics of an electromagnetic thermoelectric pump (EMTE) for a liquid metal cooled nuclear reactor refrigeration loops flow control. In order to determine the operating point of the reactor, it is indispensable the simulation of the EMTE pump along with the other components of the system, once all the working parameters are connected. So, it has been developed a computer system, named BEMTE-3 (a FORTRAN micro-computer code), which simulates the primary and secondary refrigeration components of liquid metal cooled fast space reactor. This computer code also simulates the thermoelectric conversion, with the flow being controlled by the EMTE pump with thermoelectric converters, determining the system operation point for a given nominal operating power. The BEMTE-3 is used for the study of the SP-100 primary and secondary loops thermal-hydraulic simulation and for the calculation of the operating point of the system based on data from available projects. (author)

  9. Dynamic Simulation of the Green Roofs Impact on Building Energy Performance, Case Study of Antananarivo, Madagascar

    Directory of Open Access Journals (Sweden)

    Hery Tiana Rakotondramiarana

    2015-05-01

    Full Text Available Green roofs improve building energy performance and constitute an alternative to sustainable buildings. A green roof model is dynamically coupled with a building thermal model to assess its energy performance that takes into account the indoor air temperature dynamic changes. Under the climate conditions in Antananarivo, we compared green and conventional roofs. The present study shows that green roofs protect the roof structure under extreme temperature and large temperature fluctuations. For the case of Antananarivo, the amplitude of the temperature fluctuations at the top face of the support is reduced by 28 °C when using green roof. The impact of the green roof on indoor air temperature and energy demand is investigated. The vegetation decreases the maximum indoor air temperature and improves the building thermal comfort during summer days. It has no effect on the minimum indoor air temperature, but additional soil thickness can increase it. In addition, a global sensitivity analysis, which is carried out on the proposed model without considering any specific weather data, allows us to identify the most influential parameters on the energy demand. It has been found that green roofs have almost insignificant thermal impact in insulated buildings; however, their potential prevails over the building envelope and weather characteristics in the case of non-insulated building.

  10. Direct numerical simulation of turbulent thermal boundary layers

    Science.gov (United States)

    Kong, Hojin; Choi, Haecheon; Lee, Joon Sik

    2000-10-01

    In this paper, a method of generating realistic turbulent temperature fluctuations at a computational inlet is proposed and direct numerical simulations of turbulent thermal boundary layers developing on a flat plate with isothermal and isoflux wall boundary conditions are carried out. Governing equations are integrated using a fully implicit fractional-step method with 352×64×128 grids for the Reynolds number of 300, based on the free-stream velocity and the inlet momentum thickness, and the Prandtl number of 0.71. The computed Stanton numbers for the isothermal and isoflux walls are in good agreement with power-law relations without transient region from the inlet. The mean statistical quantities including root-mean-square temperature fluctuations, turbulent heat fluxes, turbulent Prandtl number, and skewness and flatness of temperature fluctuations agree well with existing experimental and numerical data. A quadrant analysis is performed to investigate the coherence between the velocity and temperature fluctuations. It is shown that the behavior of the wall-normal heat flux is similar to that of the Reynolds shear stress, indicating close correlation between the streamwise velocity and temperature. The effect of different thermal boundary conditions at the wall on the near-wall turbulence statistics is also discussed.

  11. Numerical simulations of subcritical reactor kinetics in thermal hydraulic transient phases

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, J.; Park, W. S. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    A subcritical reactor driven by a linear proton accelerator has been considered as a nuclear waste incinerator at Korea Atomic Energy Research Institute (KAERI). Since the multiplication factor of a subcritical reactor is less than unity, to compensate exponentially decreasing fission neutrons, external neutrons form spallation reactions are essentially required for operating the reactor in its steady state. Furthermore, the profile of accelerator beam currents is very important in controlling a subcritical reactor, because the reactor power varies in accordance to the profile of external neutrons. We have developed a code system to find numerical solutions of reactor kinetics equations, which are the simplest dynamic model for controlling reactors. In a due course of our previous numerical study of point kinetics equations for critical reactors, however, we learned that the same code system can be used in studying dynamic behavior of the subcritical reactor. Our major motivation of this paper is to investigate responses of subcritical reactors for small changes in thermal hydraulic parameters. Building a thermal hydraulic model for the subcritical reactor dynamics, we performed numerical simulations for dynamic responses of the reactor based on point kinetics equations with a source term. Linearizing a set of coupled differential equations for reactor responses, we focus our research interest on dynamic responses of the reactor to variations of the thermal hydraulic parameters in transient phases. 5 refs., 8 figs. (Author)

  12. User's manual for computer code SOLTES-1 (simulator of large thermal energy systems). [For CDC 6600

    Energy Technology Data Exchange (ETDEWEB)

    Fewell, M.E.; Grandjean, N.R.; Dunn, J.C.; Edenburn, M.W.

    1978-09-01

    SOLTES simulates the steady-state response of thermal energy systems to time-varying data such as weather and loads. Thermal energy system models of both simple and complex systems can easily be modularly constructed from a library of routines. These routines mathematically model solar collectors, pumps, switches, thermal energy storage, thermal boilers, auxiliary boilers, heat exchangers, extraction turbines, extraction turbine/generators, condensers, regenerative heaters, air conditioners, heating and cooling of buildings, process vapor, etc.; SOLTES also allows user-supplied routines. The analyst need only specify fluid names to obtain readout of property data for heat-transfer fluids and constants that characterize power-cycle working fluids from a fluid property data bank. A load management capability allows SOLTES to simulate total energy systems that simultaneously follow heat and power loads and demands. Generalized energy accounting is available, and values for system performance parameters may be automatically determined by SOLTES. Because of its modularity and flexibility, SOLTES can be used to simulate a wide variety of thermal energy systems such as solar power/total energy, fossil fuel power plants/total energy, nuclear power plants/total energy, solar energy heating and cooling, geothermal energy, and solar hot water heaters.

  13. CFD Simulation of Air Velocity Distribution in Occupied Livestock Buildings

    OpenAIRE

    Svidt, Kjeld; Zhang, G.; Bjerg, B.

    1998-01-01

    In modem livestock buildings the design of the ventilation systems is important in order to obtain good air distribution. The use of Computational Fluid Dynamics for predicting the air flow and air quality makes it possible to include the effect of room geometry, equipment and occupants in the design of ventilation systems. However, it is not appropriate to include the detailed geometry of a large group of lying or standing animals affecting the air flow in the building.It is necessary to hav...

  14. Comparison of simplified and advanced building simulation tool with measured data

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik; Schiønning, Peder; Dethlefsen, Espen

    2013-01-01

    In the future building design must progress to a format where CO 2 neutral societies are optimized as a whole and innovative technologies integrated. The purpose of this paper is to demonstrate the problems using a simplified design tool to simulate a complicated building and how this may not give...

  15. Issues to Be Solved for Energy Simulation of An Existing Office Building

    Directory of Open Access Journals (Sweden)

    Ki Uhn Ahn

    2016-04-01

    Full Text Available With the increasing focus on low energy buildings and the need to develop sustainable built environments, Building Energy Performance Simulation (BEPS tools have been widely used. However, many issues remain when applying BEPS tools to existing buildings. This paper presents the issues that need to be solved for the application of BEPS tools to an existing office building. The selected building is an office building with 33 stories above ground, six underground levels, and a total floor area of 91,898 m2. The issues to be discussed in this paper are as follows: (1 grey data not ready for simulation; (2 subjective assumptions and judgments on energy modeling; (3 stochastic characteristics of building performance and occupants behavior; (4 verification of model fidelity-comparison of aggregated energy; (5 verification of model fidelity-calibration by trial and error; and (6 use of simulation model for real-time energy management. This study investigates the aforementioned issues and explains the factors that should be considered to address these issues when developing a dynamic simulation model for existing buildings.

  16. Numerical simulation of high-temperature phase transition thermal energy storage container for solar thermal power generation applications

    OpenAIRE

    Haiting CUI; Sun, Kunkun; Ning LI

    2015-01-01

    The heat storage process of the high temperature thermal energy storage container using single-stage PCM for solar thermal power generation is numerically simulated. The change curves of the PCM's temperature and liquid rate over time during the single-stage thermal stage melting process and its cloud distributions of the liquid rate at different time have been obtained. Through the analysis of the curves and cloud figures, in the premise of ensuring the heat accumulation amount, three kinds ...

  17. Modeling and simulation of the energy use in an occupied residential building in cold climate

    International Nuclear Information System (INIS)

    Highlights: ► An overview of the energy-characteristics based on illustrations in graphical figures. ► Figures to support identification and validation energy refurbishment measures. ► Emphasizing energy efficiency measures in early stage of building design. -- Abstract: In order to reduce the energy use in the building sector there is a demand for tools that can identify significant building energy performance parameters. In the work introduced in this paper presents a methodology, based on a simulation module and graphical figures, for interactive investigations of the building energy performance. The building energy use simulation program is called TEKLA and is using EN832 with an improved procedure in calculating the heat loss through the floor and the solar heat gain. The graphical figures are simple and are illustrating the savings based on retrofit measures and climate conditions. The accuracy of the TEKLA simulation was investigated on a typical single-family building in Sweden for a period of time in a space heating demand of relatively cold and mild climate. The model was found applicable for relative investigations. Further, the methodology was applied on a typical single family reference building. The climate data from three locations in Sweden were collected and a set of relevant measures were studied. The investigated examples illustrate how decisions in the early stages of the building design process can have decisive importance on the final building energy performance.

  18. Assessment of Retrofitting Measures for a Large Historic Research Facility Using a Building Energy Simulation Model

    OpenAIRE

    Young Tae Chae; Lee, Young M.; David Longinott

    2016-01-01

    A calibrated building simulation model was developed to assess the energy performance of a large historic research building. The complexity of space functions and operational conditions with limited availability of energy meters makes it hard to understand the end-used energy consumption in detail and to identify appropriate retrofitting options for reducing energy consumption and greenhouse gas (GHG) emissions. An energy simulation model was developed to study the energy usage patterns not o...

  19. Building America House Simulation Protocols - Revised October 2010

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-10-01

    This document was developed to track and manage progress toward multi-year, average whole-building energy reduction research goals for new construction and existing homes, using a consistent reference point. This report corrects editorial errors that were in the original publication.

  20. CFD Simulation of Air Velocity Distribution in Occupied Livestock Buildings

    DEFF Research Database (Denmark)

    Svidt, Kjeld; Zhang, G.; Bjerg, B.

    In modem livestock buildings the design of the ventilation systems is important in order to obtain good air distribution. The use of Computational Fluid Dynamics for predicting the air flow and air quality makes it possible to include the effect of room geometry, equipment and occupants in the de...

  1. Solar cooling - comparative study between thermal and electrical use in industrial buildings

    Science.gov (United States)

    Badea, N.; Badea, G. V.; Epureanu, A.; Frumuşanu, G.

    2016-08-01

    The increase in the share of renewable energy sources together with the emphasis on the need for energy security bring to a spotlight the field of trigeneration autonomous microsystems, as a solution to cover the energy consumptions, not only for isolated industrial buildings, but also for industrial buildings located in urban areas. The use of solar energy for cooling has been taken into account to offer a cooling comfort in the building. Cooling and air- conditioned production are current applications promoting the use of solar energy technologies. Solar cooling systems can be classified, depending on the used energy, in electrical systems using mechanical compression chillers and systems using thermal compression by absorption or adsorption. This comparative study presents the main strengths and weaknesses of solar cooling obtained: i) through the transformation of heat resulted from thermal solar panels combined with adsorption chillers, and ii) through the multiple conversion of electricity - photovoltaic panels - battery - inverter - combined with mechanical compression chillers. Both solutions are analyzed from the standpoints of energy efficiency, dynamic performances (demand response), and costs sizes. At the end of the paper, experimental results obtained in the climatic condition of Galafi city, Romania, are presented.

  2. CFD Simulation of X-Ads Downcomer Thermal Stratification

    CERN Document Server

    Anissimov, V

    2006-01-01

    This work presents a numerical simulation using CFX 4.4 of the Energy Amplifier Experimental Facility (X-ADS) downcomer channel. The simulation is focused on the Steady-State Analysis. The Intermediate Heat exchangers (IHX) of the X-ADS reference configuration are immersed in the lead-bismuth eutectic of the downcomer. Due to the absence of a physical separation between the primary coolant hot and cold collectors, two different flow paths are available in the downcomer region: inside the IHX and outside it (IHX by-pass flow). The amount of IHX by-pass flow is determined by the balance between the driving force due to buoyancy (originated by the weight difference between the cooled fluid inside the IHX and the hot outside downcomer fluid) and the IHX pressure losses. At the IHX exit the two flow paths are mixed before the core inlet. This fact provides a potential for a downcomer thermal stratification, which is influenced by the actual value of coolant flow rate outside the IHX. The amount and extension of th...

  3. A Temperature-Dependent Thermal Model of IGBT Modules Suitable for Circuit-Level Simulations

    OpenAIRE

    Wu, Rui; Wang, Huai; Ma, Ke; Ghimire, Pramod; Iannuzzo, Francesco; Blaabjerg, Frede

    2014-01-01

    Thermal impedance of IGBT modules may vary with operating conditions due to that the thermal conductivity and heat capacity of materials are temperature dependent. This paper proposes a Cauer thermal model for a 1700 V/1000 A IGBT module with temperature-dependent thermal resistances and thermal capacitances. The temperature effect is investigated by Finite Element Method (FEM) simulation based on the geometry and material information of the IGBT module. The developed model is ready for circu...

  4. Cold Thermal Storage and Peak Load Reduction for Office Buildings in Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Nabil Y.Abdel-Shafi; Ramzy R.Obaid; Ibrahim M.Jomoah

    2014-01-01

    This paper involves the investigations of the chilled water and ice cold thermal storage technologies along with the associated operating strategies for the air conditioning (AC) systems of the typical office buildings in Saudi Arabia, so as to reduce the electricity energy consumption during the peak load periods. In Saudi Arabia, the extensive use of AC for indoor cooling in offices composes a large proportion of the annual peak electricity demand. The very high temperatures over long summer periods, extending from May to October, and the low cost of energy are the key factors in the wide and extensive use of air conditioners in the kingdom. This intense cooling load adds up to the requirement increase in the capacity of power plants, which makes them under utilized during the off-peak periods. Thermal energy storage techniques are one of the effective demand-side energy management methods. Systems with cold storage shifts all or part of the electricity requirement from peak hours to off-peak hours to reduce demand charges and/or take advantage of off-peak rates. The investigations reveal that the cold thermal energy storage techniques are effective from both technical and economic perspectives in the reduction of energy consumption in the buildings during peak periods.

  5. Poverty Simulations: Building Relationships among Extension, Schools, and the Community

    Science.gov (United States)

    Franck, Karen L.; Barnes, Shelly; Harrison, Julie

    2016-01-01

    Poverty simulations can be effective experiential learning tools for educating community members about the impact of poverty on families. The project described here includes survey results from three simulations with community leaders and teachers. This project illustrated how such workshops can help Extension professionals extend their reach and…

  6. Integration of Building energy and energy supply simulations for low-energy district heating supply to energy-efficient buildings

    DEFF Research Database (Denmark)

    Dalla Rosa, Alessandro

    2012-01-01

    of the human behaviour regarding the building and link the results to the simulation program for DH networks. The results show that human behaviour can lead to 50% higher heating demand and 60% higher peak loads than expected according to reference values in standardized calculation of energy demand....... The analysis also shows that the connection of low-energy buildings to DH networks is potentially a good solution in Denmark for reaching the climatic goals, but a high degree of connection must be reached, especially for detached houses, where most of the buildings in a typical community must be connected......The future will demand implementation of C02 neutral communities, the consequences being a far more complex design of the whole energy system, since the future energy infrastructures will be dynamic and climate responsive systems. Software able to work with such level of complexity is at present...

  7. Energy Efficiency through Thermal Energy Storage - Evaluation of the Possibilities for the Swedish Building Stock, Phase 1

    OpenAIRE

    Heier, Johan; Bales, Chris; Martin, Viktoria

    2010-01-01

    As a first step in assessing the potential of thermal energy storage in Swedish buildings, the current situation of the Swedish building stock and different storage methods are discussed in this paper. Overall, many buildings are from the 1960’s or earlier having a relatively high energy demand, creating opportunities for large energy savings. The major means of heating are electricity for detached houses and district heating for multi dwelling houses and premises. Cooling needs are relativel...

  8. Selection of Weather Parameters for Air-Conditioning System Design for Buildings with Long Thermal Lag

    Institute of Scientific and Technical Information of China (English)

    GE Lian-feng; LEI Ming; CHEN You-ming

    2009-01-01

    Two building factors-a longer thermal lag of more than one hour for building envelops and a lag of indoor radiation to convert into cooling load-have impact on the instantaneous heat input and instantaneous cooling load.So the two factors should be taken into account when selecting the weather parameters for air-con-ditioning system design.This paper developed a new statistic method for the rational selection of coincident solar irradiance,dry-bulb and wet-bulb temperatures.The method was applied to historic weather records of 25 years in Hong Kong to generate coincident design weather data.And the results show that traditional design solar irra-diance,dry-bulb and wet-bulb temperatures may be significantly overestimated in many conditions,and the de-sign weather data for the three different constructions is not kept constant.

  9. Thermal distribution in small buildings: A review and analysis of recent literature

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, J.W. (Brookhaven National Lab., Upton, NY (United States)); Modera, M.P. (Lawrence Berkeley Lab., CA (United States))

    1992-09-01

    This report reviews and analyzes recent technical literature on two subjects relating to thermal distribution in small buildings: energy losses in ductwork and the energy consequences of zone control. Energy losses in ductwork stem from three factors: fan-induced infiltration, duct leakage, and conductive heat losses through duct walls. The first two mechanisms are intertwined, and together account for about half of all duct losses. Ducted forced-air distribution systems are found, on average, to be 60%--70% efficient. Zone control, that is, the ability to operate different zones of a building at different temperatures, is potentially an energy-conserving strategy, but field results suggest that the energy savings are far from automatic.

  10. Order selection of thermal models by frequency analysis of measurements for building energy efficiency estimation

    International Nuclear Information System (INIS)

    Highlights: • The partial differential heat equation is introduced in matrix representation. • The link between different representations of thermal models is presented. • Measurable variation of the output is considered for model order reduction. • Model order reduction can optimize building energy performance characterization. - Abstract: Experimental identification of the dynamic models of heat transfer in walls is needed for optimal control and characterization of building energy performance. These models use the heat equation in time domain which can be put in matrix form and then, through state-space representation, transformed in a transfer function which is of infinite order. However, the model acts as a low-pass filter and needs to respond only to the frequency spectrum present in the measured inputs. Then, the order of the transfer function can be determined by using the frequency spectrum of the measured inputs and the accuracy of the sensors. The main idea is that from two models of different orders, the one with a lower order can be used in building parameter identification, when the difference between the outputs is negligible or lower than the output measurement error. A homogeneous light wall is used as an example for a detailed study and examples of homogeneous building elements with very high and very low time constants are given. The first order model is compared with a very high order model (hundreds of states) which can be considered almost continuous in space

  11. Building Blocks for the Rapid Development of Parallel Simulations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Scientists need to be able to quickly develop and run parallel simulations without paying the high price of writing low-level message passing codes using compiled...

  12. Rigidly framed earth retaining structures thermal soil structure interaction of buildings supporting unbalanced lateral earth pressures

    CERN Document Server

    Aboumoussa, Walid

    2014-01-01

    Structures placed on hillsides often present a number of challenges and a limited number of economical choices for site design. An option sometimes employed is to use the building frame as a retaining element, comprising a Rigidly Framed Earth Retaining Structure (RFERS). The relationship between temperature and earth pressure acting on RFERS, is explored in this monograph through a 4.5 year monitoring program of a heavily instrumented in service structure. The data indicated that the coefficient of earth pressure behind the monitored RFERS had a strong linear correlation with temperature. The study also revealed that thermal cycles, rather than lateral earth pressure, were the cause of failure in many structural elements. The book demonstrates that depending on the relative stiffness of the retained soil mass and that of the structural frame, the developed lateral earth pressure, during thermal expansion, can reach magnitudes several times larger than those determined using classical earth pressure theories....

  13. Preliminary study of small scale solar test cells for solar thermal evaluation of building components

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, G. [CIEMAT, Renewable Energy Dept., Madrid (Spain)]|[CENIDET, Mechanical Engineering Dept., Cuernavaca, Morelos (Mexico); Jimenez, M.J.; Heras, M.R. [CIEMAT, Renewable Energy Dept., Madrid (Spain)

    2004-07-01

    This paper presents a preliminary study to validate small scale solar test cells for thermal evaluation of building components such as windows and roofs. The description and performance of the scale test cells are described. The validation of the thermal performance was made with the real test cell Passys indirectly by applying the classical averaging method that was initially used for the Passys cells to determine overall heat loss coefficient, UA, and the solar heat gain, gA. The use of this methodology was selected, as a first approach, to evaluate the viability of the study of scale test cells. Our preliminary results indicate that some percentage differences were high for some tests. Therefore, it is necessary to increase the period of time of the measurements of the scale test cells, in order to use dynamic system methods to reduce the percentage differences of UA and gA. (orig.)

  14. Thermal Simulation of Biogas Plants Using Mat Lab

    Directory of Open Access Journals (Sweden)

    Shaheen.M.Sain

    2014-10-01

    Full Text Available The major prerequisite for the optimum production of methane from a biogas plant is the sustenance of digester temperature within the narrow limits (300C-350C. It is experimentally investigated that, the MIT biogas plant is not maintaining optimum temperature, this decreases the efficiency and increases the detention time for charge. To maintain the plant in optimum temperature, it is necessary to find out the heat losses from the biogas plant and the external energy inputs need to operate the plant. Rate of gas yield, and the detention time (time necessary to anaerobically digest organic wastes in a biogas reactor, are favorable functions of the temperature in the digester. A thermal simulation for MIT biogas plant has developed using matlab in order to understand the heat transfer from the slurry and the gas holder to the surrounding earth and air respectively. The computation has been performed when the slurry is maintained at 200C and 300C, optimum temperature of anaerobic fermentation. If the slurry is considered to be at 350C, the optimum temperature of anaerobic fermentation, the total heat loss from the plant is higher than the heat loss when the slurry is maintained at 200C. The heat calculations provide an appraisal for the heat which has to be supplied by external means to compensate for the net heat losses which occur if the slurry is to be maintained at 350C. A solar system with auxiliary electric heater is designed for maintaining the slurry at 350C.In conclusion; the results of thermal analysis are used to define a strategy for operating biogas plant at optimum temperatures. .

  15. Savings in Cooling Energy with a Thermal Management System for LED Lighting in Office Buildings

    OpenAIRE

    Byung-Lip Ahn; Ji-Woo Park; Seunghwan Yoo; Jonghun Kim; Seung-Bok Leigh; Cheol-Yong Jang

    2015-01-01

    Light-emitting diode (LED) lighting should be considered for lighting efficiency enhancement, however, waste heat from light-emitting diode (LED) lighting increases the internal cooling load during the summer season. In order to solve this problem we propose a thermal management system for light-emitting diode (LED) lighting with a heat exchanger module integrated with the building’s heating, ventilation, and air conditioning (HVAC) system to move the lighting’s waste heat outdoors. An ex...

  16. Properties of Agro-Industrial Aerated Concrete as Potential Thermal Insulation for Building

    OpenAIRE

    Aminudin Eeydzah; Md Din Mohd Fadhil; Hussin Mohd Warid; Abdullah Abd Halid; Iwao Kenzo; Ichikawa Yo

    2016-01-01

    The present paper is aiming to provide an actual state of the development of non autoclaved Agro-Industrial aerated concrete by using multiple ashes as improvement of thermal behavior for building. The feasibility of Agro-Industrial wastes as lightweight concrete by utilizing the Palm Oil Fuel Ash (POFA) as binder replacement and bottom ash as fine aggregate was investigated in this paper. Portland cement, bottom ash, aluminum powder and lime (Ca(OH)2) were used in this study. The POFA was us...

  17. Analysis of Thermal Comfort in a Residential Room with Multiple Vents: A Case Study by Numerical Simulation Technique

    Directory of Open Access Journals (Sweden)

    D. Prakash

    2013-12-01

    Full Text Available Thermal comfort is very essential for the occupants in the residential building without air-conditioning system in the hot and arid climatic regions. In this study, the thermal comfort prevailed inside the room with window openings at their adjacent walls was analyzed under various wind directions by computational fluid dynamic technique. The CFD simulation was validated with the experimental results obtained from wind tunnel test rig and network model and found that it is having a good agreement. The room with single window opening at the adjacent walls was investigated under various wind directions and based on their prevailed uncomforted zones, the window opening at the windward side wall was splited in to multiple vents as double and triple vent system without changing window opening area. From this study, it was identified that the triple vent system reduces the indoor temperature and predicted mean vote by 0.3 and provides improved uniform thermal comfort.

  18. Calibrated energy simulations of potential energy savings in actual retail buildings

    Science.gov (United States)

    Alhafi, Zuhaira

    Retail stores are commercial buildings with high energy consumption due to their typically large volumes and long hours of operation. This dissertation assesses heating, ventilating and air conditioning saving strategies based on energy simulations with input parameters from actual retail buildings. The dissertation hypothesis is that "Retail store buildings will save a significant amount of energy by (1) modifying ventilation rates, and/or (2) resetting set point temperatures. These strategies have shown to be beneficial in previous studies. As presented in the literature review, potential energy savings ranged from 0.5% to 30% without compromising indoor thermal comfort and indoor air quality. The retail store buildings can be ventilated at rates significantly lower than rates called for in the ASHRAE Standard 62.1-2010 while maintaining acceptable indoor air quality. Therefore, two dissertation objectives are addressed: (1) Investigate opportunities to reduce ventilation rates that do not compromise indoor air quality in retail stores located in Central Pennsylvania, (2) Investigate opportunities to increase (in summer) and decrease (in winter) set point temperatures that do not compromise thermal comfort. This study conducted experimental measurements of ventilation rates required to maintain acceptable air quality and indoor environmental conditions requirements for two retail stores using ASHRAE Standard 62.1_2012. More specifically, among other parameters, occupancy density, indoor and outdoor pollutant concentrations, and indoor temperatures were measured continuously for one week interval. One of these retail stores were tested four times for a yearlong time period. Pollutants monitored were formaldehyde, carbon dioxide, particle size distributions and concentrations, as well as total volatile organic compounds. As a part of the base protocol, the number of occupants in each store was hourly counted during the test, and the results reveal that the occupant

  19. SIMULATION OF TSUNAMI FORCE ON ROWS OF BUILDINGS IN ACEH REGION AFTER TSUNAMI DISASTER IN 2004

    Directory of Open Access Journals (Sweden)

    Radianta Triatmadja

    2014-10-01

    Full Text Available After the Indian Ocean Tsunami 2004 in Aceh, houses and other buildings were reconstructed by government and Non-Governmental Organizations (NGO. The new buildings near the coastline are open directly to similar tsunami attack. The layout of such new residential are normally arranged and aligned as rows of buildings. The front rows of the buildings suffer more tsunami force due to their location that are closer to the beach and the effect of the reflection from the adjacent buildings. This research aims to analyze the tsunami force on buildings of different types, and the effect of other buildings nearby. The research was conducted using a physical model at the Hydraulic and Hydrology Laboratory, Research Centre for Engineering Science, Universitas Gadjah Mada Indonesia. The physical model simulations were carried out in a flume of 24 m long, 1.45 m wide, and 1.5 m high, that was facilitated with tsunami generator based on dam break system. The models of the buildings were made of plywood and were placed in a row perpendicular to the flume. The distance between the buildings was varied to observe the effect of the gaps. The results show that the force on the building depends on the gap between the buildings. Although the effect of the gap was more significant on low buildings, the effect of force on high buildings was more sensitive to the change of the gap size. Simple equation for practical use is proposed to calculate the tsunami force on building with the effect of nearby buildings.

  20. Thermal insulation of old buildings; Waermeschutz im Altbau. Energetische Modernisierung mit PUR-Hartschaum nach Energieeinsparverordnung (EnEV)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    In this documentation of the ''German Federation of Industry'' of the manufactures of PU rigid foams the main problems of the thermal insulation of old buildings are elucidated and exemplified. -Manufacture of PU rigid foams and thermal insulation properties. -Thermal insulations of floors, walls and roofs. -Roof constructions. -Energy saving. Laws and regulations. -Designs as helps for architects and workmen. -Costs and examples of calculations. Efficiency. -Recycling of PU rigid foams.

  1. Contribution of Portuguese Vernacular Building Strategies to Indoor Thermal Comfort and Occupants’ Perception

    Directory of Open Access Journals (Sweden)

    Jorge Fernandes

    2015-11-01

    Full Text Available Solar passive strategies that have been developed in vernacular architecture from different regions are a response to specific climate effects. These strategies are usually simple, low-tech and have low potential environmental impact. For this reason, several studies highlight them as having potential to reduce the demands of non-renewable energy for buildings operation. In this paper, the climatic contrast between northern and southern parts of mainland Portugal is presented, namely the regions of Beira Alta and Alentejo. Additionally, it discusses the contribution of different climate-responsive strategies developed in vernacular architecture from both regions to assure thermal comfort conditions. In Beira Alta, the use of glazed balconies as a strategy to capture solar gains is usual, while in Alentejo the focus is on passive cooling strategies. To understand the effectiveness of these strategies, thermal performances and comfort conditions of two case studies were evaluated based on the adaptive comfort model. Field tests included measurement of hygrothermal parameters and surveys on occupants’ thermal sensation. From the results, it has been found that the case studies have shown a good thermal performance by passive means alone and that the occupants feel comfortable, except during winter where there is the need to use simple heating systems.

  2. Properties of Agro-Industrial Aerated Concrete as Potential Thermal Insulation for Building

    Directory of Open Access Journals (Sweden)

    Aminudin Eeydzah

    2016-01-01

    Full Text Available The present paper is aiming to provide an actual state of the development of non autoclaved Agro-Industrial aerated concrete by using multiple ashes as improvement of thermal behavior for building. The feasibility of Agro-Industrial wastes as lightweight concrete by utilizing the Palm Oil Fuel Ash (POFA as binder replacement and bottom ash as fine aggregate was investigated in this paper. Portland cement, bottom ash, aluminum powder and lime (Ca(OH2 were used in this study. The POFA was used to replace Portland cement and Hydrated Lime at 0%, 5%, 10% and 15% by weight and aluminum powder was added at 0.75% dry weight in order to form bubbles. The compressive strength, water absorption, porosity and the thermal conductivity test were carried out after the concrete were water cured for 7 days and later being exposed to the air and water until 28days. The results show that the 20% replacements give the optimum strength of 7.143MPa and 30% give the best thermal conductivity with 0.48W/mK. Hence, this study aim, was to develop an agro-industrial aerated concrete good in insulation but having an optimum strength. Hence, it has been found that the more the percentage of POFA is added the lower the thermal conductivity since the pore structure is increasing and by the optimization done, 30% replacement has been chosen as the best mix design for Agro-Industrial Aerated Concrete.

  3. Radiant floor cooling coupled with dehumidification systems in residential buildings: A simulation-based analysis

    International Nuclear Information System (INIS)

    Highlights: • The floor radiant cooling in a typical apartment is analyzed. • Dehumidification devices, fan-coil and mechanical ventilation are compared. • The results are analyzed in terms of both thermal comfort and energy consumption. • The energy consumption of the dehumidifiers is higher than that of other systems. • The mechanical ventilation decreases the moisture level better than other systems. - Abstract: The development of radiant cooling has stimulated an interest in new systems based on coupling ventilation with radiant cooling. However, radiant cooling systems may cause condensation to form on an active surface under warm and humid conditions during the cooling season. This phenomenon occurs when surface temperature falls below dew point. To prevent condensation, air humidity needs to be reduced with a dehumidification device or a mechanical ventilation system. There are two main options to achieve this. The first is to use dehumidification devices that reduce humidity, but are not coupled with ventilation, i.e. devices that handle room air and leave air change to infiltrations. The second is to combine a mechanical ventilation system with dehumidifying finned coils. This study analyzes the floor radiant cooling of a typical residential apartment within a multi-storey building in three Italian climate zones by means of a detailed simulation tool. Five systems were compared in terms of both indoor thermal comfort and energy consumption: radiant cooling without dehumidification; radiant cooling with a soft dehumidification device; radiant cooling with a dehumidification device which also supplies sensible cooling; radiant cooling coupled with fan coils; and radiant cooling with a mechanical ventilation system which dehumidifies and cools

  4. Load sharing with a local thermal network fed by a microcogenerator: Thermo-economic optimization by means of dynamic simulations

    International Nuclear Information System (INIS)

    The cogeneration is the combined production of electric and/or mechanical and thermal energy starting by a single energy source; in particular in this paper the analysis will be focused on a cogeneration system with electric power lower than 15 kW (micro-cogeneration). The paper analyzes a system consisting of a natural gas-fired micro-cogeneration unit (MCHP), a heat storage and a peak boiler. The system provides thermal and electric energy to two end-users, the former is a tertiary building (office), where the generation system is located, and the latter is a residential building connected to the former through a district heating micro-grid. In order to analyze the influence of climatic conditions, two different geographical locations in Italy (Benevento and Milano) are considered, that are also characterized by different natural gas and electricity tariffs. Particular attention is paid to the choice of the users, in order to obtain more stable and continuous electric and thermal loads (load sharing approach) and to increase the operating hours per year of the MCHP unit. The operation of the MCHP is governed by a control system, aimed to optimize a thermo-economic objective function. The models representing the components, the thermo-economic objective function and the buildings have been implemented in a widely used commercial software for building simulations. The models are calibrated and validated through data obtained from experimental tests carried out in the laboratory of the University of Sannio (Benevento). The results of the simulations highlight the potential benefits of the thermal load sharing approach. In particular, this study shows that an MCHP unit connected by means of a thermal micro-grid to different users in “load sharing mode” can obtain a high number of operating hours as well as significant energy (Primary Energy Saving) and environmental (avoided CO2 equivalent emissions) benefits with respect to an appropriate reference system, even

  5. Design and Build of Reactor Simulator for Fission Surface Power Technology Demonstrator Unit

    Science.gov (United States)

    Godfroy, Thomas; Dickens, Ricky; Houts, Michael; Pearson, Boise; Webster, Kenny; Gibson, Marc; Qualls, Lou; Poston, Dave; Werner, Jim; Radel, Ross

    2011-01-01

    The Nuclear Systems Team at NASA Marshall Space Flight Center (MSFC) focuses on technology development for state of the art capability in non-nuclear testing of nuclear system and Space Nuclear Power for fission reactor systems for lunar and Mars surface power generation as well as radioisotope power systems for both spacecraft and surface applications. Currently being designed and developed is a reactor simulator (RxSim) for incorporation into the Technology Demonstrator Unit (TDU) for the Fission Surface Power System (FSPS) Program, which is supported by multiple national laboratories and NASA centers. The ultimate purpose of the RxSim is to provide heated NaK to a pair of Stirling engines in the TDU. The RxSim includes many different systems, components, and instrumentation that have been developed at MSFC while working with pumped NaK systems and in partnership with the national laboratories and NASA centers. The main components of the RxSim are a core, a pump, a heat exchanger (to mimic the thermal load of the Stirling engines), and a flow meter for tests at MSFC. When tested at NASA Glenn Research Center (GRC) the heat exchanger will be replaced with a Stirling power conversion engine. Additional components include storage reservoirs, expansion volumes, overflow catch tanks, safety and support hardware, instrumentation (temperature, pressure, flow) for data collection, and power supplies. This paper will discuss the design and current build status of the RxSim for delivery to GRC in early 2012.

  6. Thermal comfort in air-conditioned buildings in hot and humid climates--why are we not getting it right?

    Science.gov (United States)

    Sekhar, S C

    2016-02-01

    While there are plenty of anecdotal experiences of overcooled buildings in summer, evidence from field studies suggests that there is indeed an issue of overcooling in tropical buildings. The findings suggest that overcooled buildings are not a consequence of occupant preference but more like an outcome of the HVAC system design and operation. Occupants' adaptation in overcooled indoor environments through additional clothing cannot be regarded as an effective mitigating strategy for cold thermal discomfort. In the last two decades or so, several field studies and field environmental chamber studies in the tropics provided evidence for occupants' preference for a warmer temperature with adaptation methods such as elevated air speeds. It is important to bear in mind that indoor humidity levels are not compromised as they could have an impact on the inhaled air condition that could eventually affect perceived air quality. This review article has attempted to track significant developments in our understanding of the thermal comfort issues in air-conditioned office and educational buildings in hot and humid climates in the last 25 years, primarily on occupant preference for thermal comfort in such climates. The issue of overcooled buildings, by design intent or otherwise, is discussed in some detail. Finally, the article has explored some viable adaptive thermal comfort options that show considerable promise for not only improving thermal comfort in tropical buildings but are also energy efficient and could be seen as sustainable solutions.

  7. Thermal simulation of the formation and evolution of coalbed gas

    Institute of Scientific and Technical Information of China (English)

    DUAN Yi; WU Baoxiang; ZHENG Chaoyang; WANG Chuanyuan

    2005-01-01

    Thermal simulation experiment of gas generation from the peat and the coals were performed using the high temperature and pressure apparatus, at temperature ranging from 336.8-600℃, a pressure of 50MPa and two heating rates of 20℃/h and 2℃/h, and the evolution and formation of coalbed gas components were studied. Results show that for the coals, the gaseous products are mainly composed of hydrocarbon gases. However, for the peat the content of hydrocarbon gases in gaseous products is lower than that of non-hydrocarbon components. In the generated hydrocarbon gases methane is predominant and heavy hydrocarbon gases (C2-5) are present in small amount.Meanwhile, carbon dioxide (CO2) predominates the generated non-hydrocarbon gases, and hydrogen (H2) and sulfurated hydrogen (H2S) are existent in trace amount. It is also observed that temperature is the main factor controlling the evolution of coalbed gas generation. With increasing vitrinite reflectance, methane rapidly increases, CO2 sightly increases, and C2-5 hydrocarbons first increase and then decrease. The peat and Shanxi formation coal have a higher generative potential of coalbed gases than coals and Taiyuan formation coal, respectively, reflecting the effect of the property of organic matter on the characteristics of coalbed gas component generation. In this study, it is found that low heating rate is favorable for the generation of methane, H2and CO2, and the decomposition of C2-5 hydrocarbons. This shows that heating time plays an important controlling role in the generation and evolution of coalbed gases. The results obtained from the simulation experiment in the study of coalbed gases in natural system are also discussed.

  8. Energy Efficiency in Residential Buildings in Mozambique - Measurements and Simulations

    OpenAIRE

    Auziane, Gabriel

    2015-01-01

    Mozambique, situated in south-east Africa, has sub-tropical and tropical climate and plenty of natural resources for energy production. The country is however poor, and only about 25% of the population has access to electricity from the grid. A very large part of the energy used in the country is used in the residential sector, and there is a general lack of knowledge, regulations and tools concerning energy efficiency in buildings. The aim of this work is to contribute to a framework o...

  9. Weldability prediction of high strength steel S960QL after weld thermal cycle simulation

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2014-10-01

    Full Text Available This paper presents weld thermal cycle simulation of high strength steel S960QL, and describes influence of cooling time t8/5 on hardness and impact toughness of weld thermal cycle simulated specimens. Furthermore, it presents analysis of characteristic fractions done by electron scanning microscope which can contribute to determination of welding parameters for S960QL steel.

  10. Evaluation of Moisture Buffer Effects by Performing Whole-Building Simulations

    DEFF Research Database (Denmark)

    Rode, Carsten; Mendes, Nathan; K., Grau

    2004-01-01

    The humidity of rooms and the moisture conditions of materials in the enclosure of buildings depend much on each other because of the moisture exchange that takes place over the interior surfaces. These moisture influences also depend strongly on the thermal conditions of indoor spaces and enclos...

  11. Integration of thermal photovoltaic hybrid sensors to the building. Final report july 2004. Integrated research project 6.2; Integration de capteurs hybrides photovoltaiques thermiques au bati. Rapport final juillet 2004. Projet de recherche integre 6.2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The electricity and the heat are two complementary energies necessary for the accommodation. A thermal solar installation needs the electric power for the coolant fluid flow. This research project concerns the optimization of integrated solutions to the building, providing simultaneously these two energies. This document presents the proposed researches programs: analysis of the socio-economic aspects, the physical phenomena knowledge, simulation of the behavior, experimentation, hybrid components integration, simulation of the photovoltaic modules operating and thermal simulation of an electric converter. (A.L.B.)

  12. Thermal plume above a simulated sitting person with different complexity of body geometry

    DEFF Research Database (Denmark)

    Zukowska, Daria; Melikov, Arsen Krikor; Popiolek, Zbigniew J.

    2007-01-01

    . The characteristics of the thermal plume generated by a sitting person were studied using four human body simulators with different complexity of geometry but equal surface area: a vertical cylinder, a rectangular box, a dummy, and a thermal manikin. The results show that the dummy and the thermal......Occupants are one of the main heat sources in rooms. They generate thermal plumes with characteristics, which depend on geometry, surface temperature and area of the human body in contact with the surrounding air as well as temperature, velocity and turbulence intensity distribution in the room...... manikin generate almost identical thermal plumes. Therefore, with respect to the generated thermal plume, the dummy can be successfully used as a simulator of a sitting person. The cylinder and the rectangular box generate much more concentrated plumes than the thermal manikin but can correctly simulate...

  13. Mechanical-Electrochemical-Thermal Simulation of Lithium-Ion Cells

    Energy Technology Data Exchange (ETDEWEB)

    Santhanagopalan, Shriram; Zhang, Chao; Sprague, Michael A.; Pesaran, Ahmad

    2016-06-01

    Models capture the force response for single-cell and cell-string levels to within 15%-20% accuracy and predict the location for the origin of failure based on the deformation data from the experiments. At the module level, there is some discrepancy due to poor mechanical characterization of the packaging material between the cells. The thermal response (location and value of maximum temperature) agrees qualitatively with experimental data. In general, the X-plane results agree with model predictions to within 20% (pending faulty thermocouples, etc.); the Z-plane results show a bigger variability both between the models and test-results, as well as among multiple repeats of the tests. The models are able to capture the timing and sequence in voltage drop observed in the multi-cell experiments; the shapes of the current and temperature profiles need more work to better characterize propagation. The cells within packaging experience about 60% less force under identical impact test conditions, so the packaging on the test articles is robust. However, under slow-crush simulations, the maximum deformation of the cell strings with packaging is about twice that of cell strings without packaging.

  14. Quantum Thermal Bath for Path Integral Molecular Dynamics Simulation.

    Science.gov (United States)

    Brieuc, Fabien; Dammak, Hichem; Hayoun, Marc

    2016-03-01

    The quantum thermal bath (QTB) method has been recently developed to account for the quantum nature of the nuclei by using standard molecular dynamics (MD) simulation. QTB-MD is an efficient but approximate method when dealing with strongly anharmonic systems, while path integral molecular dynamics (PIMD) gives exact results but in a huge amount of computation time. The QTB and PIMD methods have been combined in order to improve the PIMD convergence or correct the failures of the QTB-MD technique. Therefore, a new power spectral density of the random force within the QTB has been developed. A modified centroid-virial estimator of the kinetic energy, especially adapted to QTB-PIMD, has also been proposed. The method is applied to selected systems: a one-dimensional double-well system, a ferroelectric phase transition, and the position distribution of an hydrogen atom in a fuel cell material. The advantage of the QTB-PIMD method is its ability to give exact results with a more reasonable computation time for strongly anharmonic systems. PMID:26799437

  15. Geosynthetic clay liners shrinkage under simulated daily thermal cycles.

    Science.gov (United States)

    Sarabadani, Hamid; Rayhani, Mohammad T

    2014-06-01

    Geosynthetic clay liners are used as part of composite liner systems in municipal solid waste landfills and other applications to restrict the escape of contaminants into the surrounding environment. This is attainable provided that the geosynthetic clay liner panels continuously cover the subsoil. Previous case histories, however, have shown that some geosynthetic clay liner panels are prone to significant shrinkage and separation when an overlying geomembrane is exposed to solar radiation. Experimental models were initiated to evaluate the potential shrinkage of different geosynthetic clay liner products placed over sand and clay subsoils, subjected to simulated daily thermal cycles (60°C for 8 hours and 22°C for 16 hours) modelling field conditions in which the liner is exposed to solar radiation. The variation of geosynthetic clay liner shrinkage was evaluated at specified times by a photogrammetry technique. The manufacturing techniques, the initial moisture content, and the aspect ratio (ratio of length to width) of the geosynthetic clay liner were found to considerably affect the shrinkage of geosynthetic clay liners. The particle size distribution of the subsoil and the associated suction at the geosynthetic clay liner-subsoil interface was also found to have significant effects on the shrinkage of the geosynthetic clay liner. PMID:24718363

  16. Geosynthetic clay liners shrinkage under simulated daily thermal cycles.

    Science.gov (United States)

    Sarabadani, Hamid; Rayhani, Mohammad T

    2014-06-01

    Geosynthetic clay liners are used as part of composite liner systems in municipal solid waste landfills and other applications to restrict the escape of contaminants into the surrounding environment. This is attainable provided that the geosynthetic clay liner panels continuously cover the subsoil. Previous case histories, however, have shown that some geosynthetic clay liner panels are prone to significant shrinkage and separation when an overlying geomembrane is exposed to solar radiation. Experimental models were initiated to evaluate the potential shrinkage of different geosynthetic clay liner products placed over sand and clay subsoils, subjected to simulated daily thermal cycles (60°C for 8 hours and 22°C for 16 hours) modelling field conditions in which the liner is exposed to solar radiation. The variation of geosynthetic clay liner shrinkage was evaluated at specified times by a photogrammetry technique. The manufacturing techniques, the initial moisture content, and the aspect ratio (ratio of length to width) of the geosynthetic clay liner were found to considerably affect the shrinkage of geosynthetic clay liners. The particle size distribution of the subsoil and the associated suction at the geosynthetic clay liner-subsoil interface was also found to have significant effects on the shrinkage of the geosynthetic clay liner.

  17. Redesigning Terraced Social Housing in the UK for Flexibility Using Building Energy Simulation with Consideration of Passive Design

    Directory of Open Access Journals (Sweden)

    Hasim Altan

    2015-05-01

    Full Text Available A chosen case study house forms the basis of this paper, which is a pilot energy-efficient social housing project, completed by one of the largest housing developers in the UK. The main aim of this study is to inform the redesign of flexible energy-efficient housing units. The housing, designed for social tenants, was built by the Accent Group in 2005, using modern construction methods and sustainable materials, based on extensive research from the adaptable and “Grow Home” principles of Avi Friedman as well as open building implementation. The first pilot scheme was designed in collaboration with the Building Energy Analysis Unit at the University of Sheffield, together with the Goddard Wybor Practise, and was a successful housing development with respect to being environmentally friendly and a low-energy design scheme for the UK climate. This paper presents redesigning of flexible terraced housing units, and their performance evaluation, using a building simulation method as well as the passive-house planning package. The aim was to plan a row of terraced houses that can not only utilize a flexible design concept in floor planning layout, but also to reduce energy consumption with a passive design with particular attention paid to material selection. In addition, building simulation work has been carried out with the use of DesignBuilder software for both thermal and energy performance evaluation. The study examines the annual energy performance and comfort conditions in the designed house to be situated in the Northeast of England, UK. A terraced house unit design is considered a flexible home that can adjust to the needs of different tenants for the purpose of achieving a sustainable building under different aspects, such as low energy, low carbon, use of renewables, and low impact materials, with flexibility by design.

  18. Biology Students Building Computer Simulations Using StarLogo TNG

    Science.gov (United States)

    Smith, V. Anne; Duncan, Ishbel

    2011-01-01

    Confidence is an important issue for biology students in handling computational concepts. This paper describes a practical in which honours-level bioscience students simulate complex animal behaviour using StarLogo TNG, a freely-available graphical programming environment. The practical consists of two sessions, the first of which guides students…

  19. An implementation of co-simulation for performance prediction of innovative integrated HVAC systems in buildings

    Energy Technology Data Exchange (ETDEWEB)

    Trcka, Marija; Wetter, Michael; Hensen, Jan L.M.

    2010-07-01

    Integrated performance simulation of buildings and heating, ventilation and air-conditioning (HVAC) systems can help reducing energy consumption and increasing level of occupant comfort. However, no singe building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to accommodate the ever-increasing complexity and rapid innovations in building and system technologies. One way to alleviate this problem is to use co-simulation. The co-simulation approach represents a particular case of simulation scenario where at least two simulators solve coupled differential-algebraic systems of equations and exchange data that couples these equations during the time integration. This paper elaborates on issues important for co-simulation realization and discusses multiple possibilities to justify the particular approach implemented in a co-simulation prototype. The prototype is verified and validated against the results obtained from the traditional simulation approach. It is further used in a case study for the proof-of-concept, to demonstrate the applicability of the method and to highlight its benefits. Stability and accuracy of different coupling strategies are analyzed to give a guideline for the required coupling frequency. The paper concludes by defining requirements and recommendations for generic cosimulation implementations.

  20. The conference of Russian Association of Engineers for Heating, Ventilation, Air-Conditioning, Heat Supply and Building Thermal Physics (ABOK

    Directory of Open Access Journals (Sweden)

    V.M. Yakubson

    2014-04-01

    Full Text Available On April, 11th, in Lenexpo the XVI conference of Russian Association of Engineers for Heating, Ventilation, Air-Conditioning, Heat Supply and Building Thermal Physics (ABOK “Effective HVAC and Heat Supply Systems” took place. There were a lot of presentations of new equipment for building systems and networks. All these reports were dedicated to the ways to make buildings more comfortable for people, to increase the energy efficiency, to reduce expenses and to improve the production efficiency. But besides the specific equipment, there were some reports dedicated to more general problems in design, installation and maintenance of building systems and networks

  1. Development of thermal simulation system for heavy section ductile iron solidification

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    A new reliable thermal simulation system for studying solidification of heavy section ductile iron has been developed using computer feedback control and artificial intelligent methods. Results of idle test indicate that the temperature in the system responses exactly to the inputted control data and the temperature control error is less than ± 0.5 %. It is convenient to simulate solidification of heavy section ductile iron using this new system. Results of thermal simulation experiments show that the differences in nodularity and number of graphite nodule per unit area in the thermal simulation specimen and the actual heavy section block is less than 5 % and 10 %, respectively.

  2. Thermal and lighting perception in four fully glazed office buildings in Santiago, Chile

    Directory of Open Access Journals (Sweden)

    Claudio Vásquez

    2013-12-01

    Full Text Available Corresponding author: Claudio Vásquez, School of Architecture, Catholic University of Chile. 1916 El Comendador str. Providencia, Santiago, ZIP: 7530091, Chile. Tel.: +56 9 92826305; E-mail: clvasque@uc.cl This paper is part of a general research project whose main objective is to establish a baseline for post-occupancy energy consumption and indoor environmental quality for office buildings in Santiago, Chile. This study aims at understanding how architectonical variables relate to, and can even determine, user comfort perception. Thus, one-year continuous monitoring in several floors at four office buildings was performed and seasonal surveys were completed. Survey participants were asked a series of questions regarding spatial orientation and comfort perception in their workspace. The data from the comfort survey and onsite measurements such as season of the year, case study, type of workspace and possibility of an outdoor view from the workstation were contrasted with the components obtained by a Principal Component Analysis (PCA. Three components were selected from the PCA, and three Maps of Perception (MP were produced. These maps were then analyzed and interpreted so as to obtain information on the general perception of thermal and lighting comfort at workspaces within several office buildings in Santiago.

  3. Thermal and lighting perception in four fully glazed office buildings in Santiago, Chile

    Directory of Open Access Journals (Sweden)

    Claudio Vásquez Záldivar

    2013-12-01

    Full Text Available This paper is part of a general research project whose main objective is to establish a baseline for post-occupancy energy consumption and indoor environmental quality for office buildings in Santiago, Chile. This study aims at understanding how architectonical variables relate to, and can even determine, user comfort perception.  Thus, one-year continuous monitoring in several floors at four office buildings was performed and seasonal surveys were completed.  Survey participants were asked a series of questions regarding spatial orientation and comfort perception in their workspace.The data from the comfort survey and onsite measurements such as season of the year, case study, type of workspace and possibility of an outdoor view from the workstation were contrasted with the components obtained by a Principal Component Analysis (PCA. Three components were selected from the PCA, and three Maps of Perception (MP were produced. These maps were then analyzed and interpreted so as to obtain information on the general perception of thermal and lighting comfort at workspaces within several office buildings in Santiago.

  4. Optimisation of trench isolated bipolar transistors on SOI substrates by 3D electro-thermal simulations

    Science.gov (United States)

    Nigrin, S.; Armstrong, G. A.; Kranti, A.

    2007-09-01

    This paper provides a comprehensive analysis of thermal resistance of trench isolated bipolar transistors on SOI substrates based on 3D electro-thermal simulations calibrated to experimental data. The impact of emitter length, width, spacing and number of emitter fingers on thermal resistance is analysed in detail. The results are used to design and optimise transistors with minimum thermal resistance and minimum transistor area.

  5. Bio-fiber from field to thermal insulation of building insulation of building; Kasvikuitu pellolta rakennuksen laemmoeneristeeksi

    Energy Technology Data Exchange (ETDEWEB)

    Kauriinvaha, E.; Viljanen, M.; Pasila, A.; Kymaelaeinen, H.-R.; Pehkonen, A.

    2001-07-01

    The study has been conducted in cooperation of Laboratory of Structural Engineering and Building Physics of Helsinki University of Technology and Department of Agriculture and Household Technology of Helsinki University. The results from the feasibility study have been basis for the second phase of the study. The second phase included the studies of production of raw material, preprocessing and the thermal and moisture physical behavior of bio-fiber based thermal insulation materials. On the basis of the results quality requirements of raw material and insulation material are presented. Publication 'The Production Line of Bio-fiber Based Thermal Insulation Materials. Feasibility Study' has been published. Flax and hemp fibers can be harvested in fall or in spring. Spring harvesting was done using dry-line technology. The seeds of flax are harvested in autumn and the fibers are dry. Due to long and strong fibers the harvesting of fiber flax and hemp differ from the harvesting of cereal. Speed and inertia force of the cutting blade must be higher when harvesting flax and hemp. The blade also blocks up and becomes blunt faster. The mentioned problems were solved by developing the materials and the blade of the combined harvester. In order to improve the durability and cutting efficiency a band saw based blade was developed. With slow speed the power consumption of the developed device was 5-10 % lower than that of the conventional blade. For the processing of flax and hemp stalks a hammer mill based defibering and a separation device was developed. The fibers included 10-17 % of strives so that the strive content of autumn harvested flax was highest and of spring harvested hemp lowest. The fiber yield of spring harvested materials was 20 - 30 Tic and of autumn harvested 10-15 %. From spring harvested flax 500-1000 kg/ha and from hemp 1500 kg/ha of loose fill insulation material without additives can be obtained. Thermal insulation for buildings can be

  6. The new research centre of the Brazilian Petroleum Company in Rio de Janeiro, Brazil: The achievements in the thermal performance of air-conditioned buildings in the tropics

    Energy Technology Data Exchange (ETDEWEB)

    Brandao, Rafael; Marcondes, Monica Pereira; De Benedetto, Gisele S.; Goncalves, Joana Carla Soares; Duarte, Denise Helena Silva; Ramos, Jose Ovidio [Laboratorio de Conforto Ambiental e Eficiencia Energetica (LABAUT), Departamento de Tecnologia da Arquitetura (AUT), Faculdade de Arquitetura e Urbanismo, Universidade de Sao Paulo (FAUUSP), Sao Paulo, Brasil, Rua do Lago, 876, Cidade Universitaria, 05508-900 Sao Paulo, SP (Brazil)

    2008-07-01

    The study on the thermal performance of the air-conditioned buildings of the new research centre of the Brazilian Petroleum Company, in the tropical climate of Rio de Janeiro, was part of a bigger research and consultancy project involving environmental issues. The architectural design was the subject of a national competition in 2004, encompassing over 100,000 m{sup 2}. According to the design brief, out of the 10 buildings of the new research centre, 7 have to be either completely or partially air-conditioned, due to specific occupation requirements. The challenge for better thermal performance was related to systems' energy efficiency, to the introduction of natural ventilation and to the notion of adaptive comfort, which were verified with the support of thermal dynamic simulations. At the early stages of the assessments, the potential for natural ventilation in the working spaces considering the mixed-mode strategy achieved 30% of occupation hours. However, the development of the design project led to fully air-conditioned working spaces, due to users' references regarding the conventional culture of the office environment. Nevertheless, the overall architectural approach in accordance to the climatic conditions still showed a contribution to the buildings' energy efficiency. (author)

  7. Nanocluster building blocks of artificial square spin ice: Stray-field studies of thermal dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Pohlit, Merlin, E-mail: pohlit@physik.uni-frankfurt.de; Porrati, Fabrizio; Huth, Michael; Müller, Jens [Institute of Physics, Goethe-University Frankfurt, Frankfurt/Main (Germany); Ohno, Yuzo; Ohno, Hideo [Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Sendai (Japan)

    2015-05-07

    We present measurements of the thermal dynamics of a Co-based single building block of an artificial square spin ice fabricated by focused electron-beam-induced deposition. We employ micro-Hall magnetometry, an ultra-sensitive tool to study the stray field emanating from magnetic nanostructures, as a new technique to access the dynamical properties during the magnetization reversal of the spin-ice nanocluster. The obtained hysteresis loop exhibits distinct steps, displaying a reduction of their “coercive field” with increasing temperature. Therefore, thermally unstable states could be repetitively prepared by relatively simple temperature and field protocols allowing one to investigate the statistics of their switching behavior within experimentally accessible timescales. For a selected switching event, we find a strong reduction of the so-prepared states' “survival time” with increasing temperature and magnetic field. Besides the possibility to control the lifetime of selected switching events at will, we find evidence for a more complex behavior caused by the special spin ice arrangement of the macrospins, i.e., that the magnetic reversal statistically follows distinct “paths” most likely driven by thermal perturbation.

  8. 3D COMPUTER SIMULATION FOR LIGNIFICATION OF ANCIENT CHINESE TIMBER BUILDINGS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A pioneer research work was carried out by investigators engaged in surveying and mapping for describing ancient Chinese timber buildings by 3D frame graphs w ith a computer.Users can know the structural layers and the assembly process of the se buildings if the frame graphs are processed further with a computer model.Th is can be implemented by computer simulation technique.This technique display t he raw data on the screen of a computer and interactively manage them by combini ng technologies from computer graphics and image processing,multi-media technol ogy,artificial intelligence,highly parallel real-time computation technique an d human behavior science.This paper presents the implementing procedure of ligni fi cation simulation for large-sized wooden buildings as well as 3D dynamic assembl y of these buildings under the 3DS MAX environment.The results from computer sim ulation are also shown in the paper.

  9. The Building Fabric Thermal Performance of Passivhaus Dwellings—Does It Do What It Says on the Tin?

    Directory of Open Access Journals (Sweden)

    David Johnston

    2016-01-01

    Full Text Available The Passivhaus (or Passive House Standard is one of the world’s most widely known voluntary energy performance standards. For a dwelling to achieve the Standard and be granted Certification, the building fabric requires careful design and detailing, high levels of thermal insulation, building airtightness, close site supervision and careful workmanship. However, achieving Passivhaus Certification is not a guarantee that the thermal performance of the building fabric as designed will actually be achieved in situ. This paper presents the results obtained from measuring the in situ whole building heat loss coefficient (HLC of a small number of Certified Passivhaus case study dwellings. They are located on different sites and constructed using different technologies in the UK. Despite the small and non-random nature of the dwelling sample, the results obtained from the in situ measurements revealed that the thermal performance of the building fabric, for all of the dwellings, performed very close to the design predictions. This suggests that in terms of the thermal performance of the building fabric, Passivhaus does exactly what it says on the tin.

  10. Re-adaptation of Malay House Thermal Comfort Design Elements into Modern Building Elements – Case Study of Selangor Traditional Malay House & Low Energy Building in Malaysia

    Directory of Open Access Journals (Sweden)

    Nur Hidayahtuljamilah Ramli

    2012-01-01

    Full Text Available The traditional Malay house is one of the richest components of Malay’s cultural heritage in Malaysia. Generally, the traditional Malay house is a reflection of the Malay community’s way of living. With greater global awareness of the environment and a renewed perspective on contemporary Malaysian architecture, architects and designers are once again looking for tropical solutions in building design. One of the main characteristics of traditional Malay house is that they are designed with a deep understanding and respect for nature, but this design-with-nature approach is no longer found in the modern buildings. The purpose is therefore to study the thermal comfort design elements such as building orientation, interior layout space, natural ventilation and lighting, window designs, and stack effect on the roof design. The investigation was carried out through observations, interviews and some research visits. A comprehensive research was accomplished on the adaptation of Malay house architecture elements with selected the Selangor traditional Malay house as the key study and one modern building which is the Ministry of Energy, Green Technology & Water (MEGTW building, Putrajaya. This study attempts to have recorded information for those who are interested and for the future generation because the traditional Malay house was evolved by the Malays over generations, adapting to their needs, culture and environment. This study is crucial to revive the awareness in the understanding and appreciation of the technique of thermal comfort design elements of traditional Malay house adapted into modern building design.

  11. Micromechanical Simulation of Thermal Cyclic Behavior of ZrO2/Ti Functionally Graded Thermal Barrier Coatings

    OpenAIRE

    Hideaki Tsukamoto

    2015-01-01

    This study numerically investigates cyclic thermal shock behavior of ZrO2/Ti functionally graded thermal barrier coatings (FG TBCs) based on a nonlinear mean-field micromechanical approach, which takes into account the time-independent and dependent inelastic deformation, such as plasticity of metals, creep of metals and ceramics, and diffusional mass flow at the ceramic/metal interface. The fabrication processes for the FG TBCs have been also considered in the simulation. The effect of creep...

  12. Correlation between subjective assessments of local thermal discomfort and thermal manikin measurements in a simulated aircraft cabin

    DEFF Research Database (Denmark)

    Zukowska, Daria; Strøm-Tejsen, Peter; Jama, Agnieszka;

    2005-01-01

    The thermal environment in a 21-seat simulated section of an aircraft cabin installed in a climate chamber was investigated. Using two thermal manikins and fourteen heated cylin-ders to represent passengers, measurements were carried out at cabin temperatures of 20.6°C, 23.3°C and 26.1°C (69°F, 74...

  13. The thermal conductivity and thermal rectification of carbon nanotubes studied using reverse non-equilibrium molecular dynamics simulations

    International Nuclear Information System (INIS)

    The thermal conductivity of single-walled and multi-walled carbon nanotubes has been investigated as a function of the tube length L, temperature and chiral index using non-equilibrium molecular dynamics simulations. In the ballistic-diffusive regime the thermal conductivity follows a Lα law. The exponent α is insensitive to the diameter of the carbon nanotube; α∼0.77 has been derived for short carbon nanotubes at room temperature. The temperature dependence of the thermal conductivity shows a peak before falling at higher temperatures (>500 K). The phenomenon of thermal rectification in nanotubes has been investigated by gradually changing the atomic mass in the tube-axial direction as well as by loading extra masses on the terminal sites of the tube. A higher thermal conductivity occurs when heat flows from the low-mass to the high-mass region.

  14. An Automated BIM Model to Conceptually Design, Analyze, Simulate, and Assess Sustainable Building Projects

    Directory of Open Access Journals (Sweden)

    Farzad Jalaei

    2014-01-01

    Full Text Available Quantifying the environmental impacts and simulating the energy consumption of building’s components at the conceptual design stage are very helpful for designers needing to make decisions related to the selection of the best design alternative that would lead to a more energy efficient building. Building Information Modeling (BIM offers designers the ability to assess different design alternatives at the conceptual stage of the project so that energy and life cycle assessment (LCA strategies and systems are attained. This paper proposes an automated model that links BIM, LCA, energy analysis, and lighting simulation tools with green building certification systems. The implementation is within developing plug-ins on BIM tool capable of measuring the environmental impacts (EI and embodied energy of building components. Using this method, designers will be provided with a new way to visualize and to identify the potential gain or loss of energy for the building as a whole and for each of its associated components. Furthermore, designers will be able to detect and evaluate the sustainability of the proposed buildings based on Leadership in Energy and Environmental Design (LEED rating system. An actual building project will be used to illustrate the workability of the proposed methodology.

  15. Experimental study of passive cooling of building facade using phase change materials to increase thermal comfort in buildings in hot humid areas

    Directory of Open Access Journals (Sweden)

    A. A. Madhumathi, B. M.C. Sundarraja

    2012-01-01

    Full Text Available Storage of cooler night temperatures using Phase Change Material (PCM energy storage technique, for cooling of ambient air during hot day times can be an alternate of current cooling techniques in building sector. This work presents the results of an experimental set-up to test energy saving potential of phase change materials with typical construction materials in building facade in Hot-Humid Climatic Regions in real conditions. The main objective of this research is to demonstrate experimentally that it is possible to improve the thermal comfort and reduce the energy consumption of a building without substantial increase in the weight of the construction materials with the inclusion of PCM. This research was conducted to study and evaluate the performance of the existing materials integrated with Organic PCM Polyethylene glycol (PEG E600. This research suggested that the heat gain is significantly reduced when the PCM is incorporated into the brick (conventional building material.

  16. Simulation on spread of fire smoke in the elevator shaft for a high-rise building

    OpenAIRE

    Yunchun Xia

    2014-01-01

    Spread of fire smoke in the elevator shaft of a high-rise building is influenced by many driving facts. We simulate smoke spreading in the elevator shaft, stair room, and pre-chamber with and without different supplied pressurized air. The simulation shows that smoke moves very fast in the elevator shaft. When a 12 floor high-rise building is in fire, smoke can fill up the elevator shaft in less than 1.5 min after a fire started, temperature in the elevator shaft can be higher than 187°C in 5...

  17. Building of Nuclear Ship Engineering Simulation System development of the simulator for the integral type reactor

    International Nuclear Information System (INIS)

    JAERI had carried out the design study of a light-weight and compact integral type reactor of power 100 MWth with passive safety as a power source for the future nuclear ships, and completed an engineering design. To confirm the design and operation performance and to utilize the study of automation of the operations of reactor, we developed a real-time simulator for the integral type reactor. This simulator is a part of Nuclear Ship Engineering Simulation System (NESSY) and on the same hardware as 'Mutsu' simulator which was developed to simulate the first Japanese nuclear ship Mutsu'. Simulation accuracy of 'Mutsu' simulator was verified by comparing the simulation results With data got in the experimental voyage of 'Mutsu'. The simulator for the integral type reactor uses the same programs which were used in 'Mutsu' simulator for the separate type PWR, and the simulated results are approximately consistent with the calculated values using RELAP5/MOD2 (The later points are reported separately). Therefore simulation accuracy of the simulator for the integral type reactor is also expected to be reasonable, though it is necessary to verify by comparing with the real plant data or experimental data in future. We can get the perspectives to use as a real-time engineering simulator and to achieve the above-mentioned aims. This is a report on development of the simulator for the integral type reactor mainly focused on the contents of the analytical programs expressed the structural features of reactor. (author)

  18. Numerical simulation of seismic response of a base isolated building with low shear modulus rubber isolators

    International Nuclear Information System (INIS)

    This paper describes seismic-response simulations of a base-isolated building subjected to actual earthquakes using the 3-D computer program, SISEC, developed at Argonne National Laboratory. The isolation system consists of six medium shape factor, high damping, and low shear modulus rubber bearings. To ensure the accuracy of analytical simulation, recorded data of full-size reinforced concrete structures located in Sendai, Japan are used as the benchmarks for comparisons of numerical simulations with observations. Results obtained from both analytical simulations and earthquake observations indicate that the advantage of base isolation in mitigating the acceleration of superstructure is very pronounced. For the two representative earthquakes, one had the strongest ground motion and the other one had similar magnitudes as the rest of the earthquakes recorded at the test site, the simulated accelerations at the roof level of the isolated building are about 20% to 30% of the ordinary building accelerations. Also, results reveal that for both ordinary and base-isolated buildings the computed accelerations agree reasonably well with those recorded

  19. Agent-based simulation of building evacuation using a grid graph-based model

    Science.gov (United States)

    Tan, L.; Lin, H.; Hu, M.; Che, W.

    2014-02-01

    Shifting from macroscope models to microscope models, the agent-based approach has been widely used to model crowd evacuation as more attentions are paid on individualized behaviour. Since indoor evacuation behaviour is closely related to spatial features of the building, effective representation of indoor space is essential for the simulation of building evacuation. The traditional cell-based representation has limitations in reflecting spatial structure and is not suitable for topology analysis. Aiming at incorporating powerful topology analysis functions of GIS to facilitate agent-based simulation of building evacuation, we used a grid graph-based model in this study to represent the indoor space. Such model allows us to establish an evacuation network at a micro level. Potential escape routes from each node thus could be analysed through GIS functions of network analysis considering both the spatial structure and route capacity. This would better support agent-based modelling of evacuees' behaviour including route choice and local movements. As a case study, we conducted a simulation of emergency evacuation from the second floor of an official building using Agent Analyst as the simulation platform. The results demonstrate the feasibility of the proposed method, as well as the potential of GIS in visualizing and analysing simulation results.

  20. Agent-based simulation of building evacuation using a grid graph-based model

    International Nuclear Information System (INIS)

    Shifting from macroscope models to microscope models, the agent-based approach has been widely used to model crowd evacuation as more attentions are paid on individualized behaviour. Since indoor evacuation behaviour is closely related to spatial features of the building, effective representation of indoor space is essential for the simulation of building evacuation. The traditional cell-based representation has limitations in reflecting spatial structure and is not suitable for topology analysis. Aiming at incorporating powerful topology analysis functions of GIS to facilitate agent-based simulation of building evacuation, we used a grid graph-based model in this study to represent the indoor space. Such model allows us to establish an evacuation network at a micro level. Potential escape routes from each node thus could be analysed through GIS functions of network analysis considering both the spatial structure and route capacity. This would better support agent-based modelling of evacuees' behaviour including route choice and local movements. As a case study, we conducted a simulation of emergency evacuation from the second floor of an official building using Agent Analyst as the simulation platform. The results demonstrate the feasibility of the proposed method, as well as the potential of GIS in visualizing and analysing simulation results

  1. Influence of measurement uncertainty on classification of thermal environment in buildings according to European Standard EN 15251

    DEFF Research Database (Denmark)

    Kolarik, Jakub; Olesen, Bjarne W.

    2015-01-01

    European Standard EN 15 251 in its current version does not provide any guidance on how to handle uncertainty of long term measurements of indoor environmental parameters used for classification of buildings. The objective of the study was to analyse the uncertainty for field measurements...... measurements of operative temperature at two measuring points (south/south-west and north/northeast orientation). Results of the present study suggest that measurement uncertainty needs to be considered during assessment of thermal environment in existing buildings. When expanded standard uncertainty was taken...... of operative temperature and evaluate its effect on categorization of thermal environment according to EN 15251. A data-set of field measurements of operative temperature four office buildings situated in Denmark, Italy and Spain was used. Data for each building included approx. one year of continuous...

  2. Thermal responses and its relation with the building outdoor conditions; Respuestas termicas y su relacion con la envolvente del edificio

    Energy Technology Data Exchange (ETDEWEB)

    Marincic, Irene [Universidad de Sonora, Hermosillo, Sonora (Mexico); Isalgue, Antoni [Universidad Politecnica de Cataluna, Barcelona (Spain)

    2000-07-01

    In order to understand and to control the indoor thermal behavior in buildings, it is necessary to know the origin of the energies coming into and outside the building, identifying the geometric factors and physical properties, that can modify the thermal balance of the system. In this work, we analyze the thermal behavior of a building experimentally, related with its exterior conditions. Specifically, we analyze the thermal response indoors at different distances from the building envelope, which implies different thermal insulation situations. Supported on temperature measurements in a residential building, which is representative of local construction styles (adjacent other buildings), we analyze the thermal response effects depending on the distances between the considered points and the envelope and on the insulation between both. Applying a methodology based on experimental transfer functions of buildings, the thermal behavior in the temporary and frequency domains is evaluated. With this methodology, it is possible to visualize certain phenomena and to obtain thermal parameters that characterize the dynamic aspects of the thermal response. The main scope is to extract information from the building analysis, in order to extrapolate the behavior conclusions to a proper thermal design of similar constructions. From the thermal responses analysis at different spatial localization, we conclude that the distance from the building envelope (and also its properties) has a great influence on thermal inertia effects, which can modify importantly the thermal response. This phenomena has a parallelism with the skin effect of the magnetic fields penetration in conductors. The spatial localization implies a certain thermal mass involved in each case, which controls the penetration of exterior thermal oscillation. [Spanish] Para poder entender y controlar los comportamientos termicos en el interior de los edificios, es necesario conocer el origen de las energias que

  3. Dynamic simulations to develop a natural ventilation concept for an office building

    OpenAIRE

    Thewes, Andreas; Maas, Stefan; SCHOLZEN, Frank; Waldmann, Danièle; Zuerbes, Arno

    2010-01-01

    The Sustainability Group of the University of Luxembourg defined for their new buildings a maximum thermal end-energy of 14 kWh/(m3a) and an electricity consumption for HVAC and lighting below 6 kWh/(m3a). Therefore it was necessary to avoid active cooling loads and mechanical ventilation in the offices and small lecture rooms. The well insulated and air-tight façade, including special outside shading elements which were designed as a grid over the complete building envelope, was ...

  4. Simulation-based education for building clinical teams

    Directory of Open Access Journals (Sweden)

    Marshall Stuart

    2010-01-01

    Full Text Available Failure to work as an effective team is commonly cited as a cause of adverse events and errors in emergency medicine. Until recently, individual knowledge and skills in managing emergencies were taught, without reference to the additional skills required to work as part of a team. Team training courses are now becoming commonplace, however their strategies and modes of delivery are varied. Just as different delivery methods of traditional education can result in different levels of retention and transfer to the real world, the same is true in team training of the material in different ways in traditional forms of education may lead to different levels of retention and transfer to the real world, the same is true in team training. As team training becomes more widespread, the effectiveness of different modes of delivery including the role of simulation-based education needs to be clearly understood. This review examines the basis of team working in emergency medicine, and the components of an effective emergency medical team. Lessons from other domains with more experience in team training are discussed, as well as the variations from these settings that can be observed in medical contexts. Methods and strategies for team training are listed, and experiences in other health care settings as well as emergency medicine are assessed. Finally, best practice guidelines for the development of team training programs in emergency medicine are presented.

  5. Note: Local thermal conductivities from boundary driven non-equilibrium molecular dynamics simulations

    International Nuclear Information System (INIS)

    We report non-equilibrium molecular dynamics simulations of heat transport in models of molecular fluids. We show that the “local” thermal conductivities obtained from non-equilibrium molecular dynamics simulations agree within numerical accuracy with equilibrium Green-Kubo computations. Our results support the local equilibrium hypothesis for transport properties. We show how to use the local dependence of the thermal gradients to quantify the thermal conductivity of molecular fluids for a wide range of thermodynamic states using a single simulation

  6. Monte-Carlo simulations of thermal reversal in granular planar media

    International Nuclear Information System (INIS)

    A general model is developed to simulate thermally agitated magnetization reversal in granular planar media. The modeled system is a two-dimensional hexagonal array with 40x40 grains. In this work, two systems were modeled; one consists of cobalt nanoparticles (D=20 nm) with an average anisotropy coupling constant a(=KV/kT)=200, and another consists of FePt nanoparticles (D=5 nm) with a=80. For both media, the time dependence of thermal coercivity at different array separations d is simulated. These simulations showed that interaction effects slow down the time variation of thermal coercivity

  7. Synergetic Effect between Lighting Efficiency Enhancement and Building Energy Reduction Using Alternative Thermal Operating System of Indoor LED Lighting

    OpenAIRE

    Byung-Lip Ahn; Ji-Woo Park; Seunghwan Yoo; Jonghun Kim; Hakgeun Jeong; Seung-Bok Leigh; Cheol-Yong Jang

    2015-01-01

    We investigated the synergetic effect between light-emitting diode (LED) lighting efficiency and building energy savings in heating and cooling using an alternative thermal operating system (ATOS) of indoor LED lighting integrated with the ventilation system of a building as an active cooling device. The heat generated from LED lighting and the indoor lighting illuminance were experimentally determined. The indoor heat gains in cooling and heating periods were determined using measurement dat...

  8. A prototype data archive for the PIER 'thermal distribution systems in commercial buildings' project

    Energy Technology Data Exchange (ETDEWEB)

    Diamond, Rick C.; Wray, Craig P.; Smith, Brian V.; Dickerhoff, Darryl J.; Matson, Nance E.; Cox, Skylar A.

    2004-01-01

    A prototype archive for a selection of building energy data on thermal distribution systems in commercial buildings was developed and pilot tested. While the pilot demonstrated the successful development of the data archive prototype, several questions remain about the usefulness of such an archive. Specifically, questions on the audience, frequency of use, maintenance, and updating of the archive would need to be addressed before this prototype is taken to the next level.

  9. Micromechanical Simulation of Thermal Cyclic Behavior of ZrO2/Ti Functionally Graded Thermal Barrier Coatings

    Directory of Open Access Journals (Sweden)

    Hideaki Tsukamoto

    2015-03-01

    Full Text Available This study numerically investigates cyclic thermal shock behavior of ZrO2/Ti functionally graded thermal barrier coatings (FG TBCs based on a nonlinear mean-field micromechanical approach, which takes into account the time-independent and dependent inelastic deformation, such as plasticity of metals, creep of metals and ceramics, and diffusional mass flow at the ceramic/metal interface. The fabrication processes for the FG TBCs have been also considered in the simulation. The effect of creep and compositional gradation patterns on micro-stress states in the FG TBCs during thermal cycling has been examined in terms of the amplitudes, ratios, maximum and mean values of thermal stresses. The compositional gradation patterns highly affect thermal stress states in case of high creep rates of ZrO2. In comparison with experimental data, maximum thermal stresses, amplitudes and ratios of thermal stresses can be effective parameters for design of such FG TBCs subject to cyclic thermal shock loadings.

  10. Opportunities and constraints of presently used thermal manikins for thermo-physiological simulation of the human body

    Science.gov (United States)

    Psikuta, Agnes; Kuklane, Kalev; Bogdan, Anna; Havenith, George; Annaheim, Simon; Rossi, René M.

    2016-03-01

    Combining the strengths of an advanced mathematical model of human physiology and a thermal manikin is a new paradigm for simulating thermal behaviour of humans. However, the forerunners of such adaptive manikins showed some substantial limitations. This project aimed to determine the opportunities and constraints of the existing thermal manikins when dynamically controlled by a mathematical model of human thermal physiology. Four thermal manikins were selected and evaluated for their heat flux measurement uncertainty including lateral heat flows between manikin body parts and the response of each sector to the frequent change of the set-point temperature typical when using a physiological model for control. In general, all evaluated manikins are suitable for coupling with a physiological model with some recommendations for further improvement of manikin dynamic performance. The proposed methodology is useful to improve the performance of the adaptive manikins and help to provide a reliable and versatile tool for the broad research and development domain of clothing, automotive and building engineering.

  11. Numerical simulations of turbulent thermal, bubble and hybrid plumes

    Science.gov (United States)

    Fabregat, Alexandre; Dewar, William K.; Özgökmen, Tamay M.; Poje, Andrew C.; Wienders, Nicolas

    2015-06-01

    To understand the near-field dynamics of blowout plumes such as the one produced by the 2010 Deepwater Horizon oil spill in the Gulf of Mexico, the effects of gas bubbles on turbulent mixing and entrainment are studied via turbulence resolving simulations. We compare the evolution of three plumes where extremely large buoyancy anomalies are produced either thermally (single phase), solely by an imposed gas phase volume fraction, or by a combination of both buoyancy forcings. The plumes, with identical volume, momentum and buoyancy fluxes at the inlet, are released into an environment stratified with a constant temperature gradient. To clarify the first-order effects of dynamically active, dispersed bubbles, we employ a simple model which neglects the momentum of the gas phase while retaining bubble induced buoyancy in the seawater momentum equation. The gas phase is then distinguished by a single, measurable parameter, the slip velocity relative to that of the liquid phase. We find that bubbles, parameterized simply by a constant slip velocity, without any explicit assumptions of direct bubble induced turbulent production, significantly increase turbulent mixing in the plume in agreement with previous experimental results. Examination of mean momenta and turbulent kinetic energy budgets shows that the increased turbulence is due to direct modification of the mean profiles of both the momentum and the active scalar fields by the slipping gas phase. The narrowing of the active scalar field in the two-phase flow results in larger direct buoyancy production of turbulent energy at all vertical levels. The turbulence production is, however, primarily mechanical. At modest values of z/D, where the slip velocity is only a small fraction of the liquid phase velocity, slip stretches the mean vertical velocity field producing larger radial gradients and increased conversion of mean to turbulent energy. This first order effect, acting on the mean vertical velocity component

  12. Breathing façades: a new concept to create dynamic thermal ambiances in buildings located in hot climates

    OpenAIRE

    Elghawaby, Mahmoud

    2012-01-01

    International audience Mimicking nature is not a new approach, but has been recently reformu-lated under the scientific term: "biomimicry". It aims to innovate non-biological systems inspired by nature. This article proposes a new rereading of this concept in architecture and in particular in building ventilation systems. The various methods of thermal adaptation to hot climat found in nature provide a wide source of inspiration in order to develop new concepts for achieving thermal comfor...

  13. Dynamic simulation of residential buildings with seasonal sorption storage of solar energy - parametric analysis

    OpenAIRE

    Hennaut, Samuel; Thomas, Sébastien; Davin, Elisabeth; Andre, Philippe

    2011-01-01

    This work focuses on the evaluation of the performances of a solar combisystem coupled to seasonal thermochemical storage using SrBr2/H20 as adsorbent/adsorbate couple. The objective is to determine the characteristics required for solar system and storage reactor to reach a 100 % solar fraction for a building with a low heating load. The complete system, including the storage reactor, is simulated, using the dynamic simulation software TRNSYS. The influence of some components and p...

  14. Virtual Design Studio (VDS) - Development of an Integrated Computer Simulation Environment for Performance Based Design of Very-Low Energy and High IEQ Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yixing [Building Energy and Environmental Systems Lab. (BEESL), Syracuse, NY (United States); Zhang, Jianshun [Syracuse Univ., NY (United States); Pelken, Michael [Syracuse Univ., NY (United States); Gu, Lixing [Univ. of Central Florida, Orlando, FL (United States); Rice, Danial [Building Energy and Environmental Systems Lab. (BEESL), Syracuse, NY (United States); Meng, Zhaozhou [Building Energy and Environmental Systems Lab. (BEESL), Syracuse, NY (United States); Semahegn, Shewangizaw [Building Energy and Environmental Systems Lab. (BEESL), Syracuse, NY (United States); Feng, Wei [Building Energy and Environmental Systems Lab. (BEESL), Syracuse, NY (United States); Ling, Francesca [Syracuse Univ., NY (United States); Shi, Jun [Building Energy and Environmental Systems Lab. (BEESL), Syracuse, NY (United States); Henderson, Hugh [CDH Energy, Cazenovia, NY (United States)

    2013-09-01

    on evaluating thermal performance, air quality and lighting environmental quality because of their strong interaction with the energy performance of buildings. The VDS software framework contains four major functions: 1) Design coordination: It enables users to define tasks using the Input-Process-Output flow approach, which specifies the anticipated activities (i.e., the process), required input and output information, and anticipated interactions with other tasks. It also allows task scheduling to define the work flow, and sharing of the design data and information via the internet. 2) Modeling and simulation: It enables users to perform building simulations to predict the energy consumption and IEQ conditions at any of the design stages by using EnergyPlus and a combined heat, air, moisture and pollutant simulation (CHAMPS) model. A method for co-simulation was developed to allow the use of both models at the same time step for the combined energy and indoor air quality analysis. 3) Results visualization: It enables users to display a 3-D geometric design of the building by reading BIM (building information model) file generated by design software such as SketchUp, and the predicted results of heat, air, moisture, pollutant and light distributions in the building. 4) Performance evaluation: It enables the users to compare the performance of a proposed building design against a reference building that is defined for the same type of buildings under the same climate condition, and predicts the percent of improvements over the minimum requirements specified in ASHRAE Standard 55-2010, 62.1-2010 and 90.1-2010. An approach was developed to estimate the potential impact of a design factor on the whole building performance, and hence can assist the user to identify areas that have most pay back for investment. The VDS software was developed by using C++ with the conventional Model, View and Control (MVC) software architecture. The software has been verified by using a

  15. Climatic zoning for the calculation of the thermal demand of buildings in Extremadura (Spain)

    Science.gov (United States)

    Moral, Francisco J.; Pulido, Elena; Ruíz, Antonio; López, Fernando

    2016-05-01

    The present work reports on a methodology to assess the climatic severity of a particular geographic region as compared to specific information available in the current regulations. The viability for each of the 387 municipalities in the Autonomous Community of Extremadura (Spain) is analysed, making a distinction between those with reliable climate reports and those for which no such information is available. In the case study, although the weather conditions in Extremadura are quite homogeneous according to the Spanish Technical Building Code (STBC 2015) classification and most areas are associated to zone C4 (soft winters and hot summers), the southern area in the region is associated to zone D1, similar to the north of Spain, where winters and summers are cool, which does not coincide with the actual climate in the south of Extremadura. The general climatic homogeneity in Extremadura was also highlighted with the new procedure, predominating zone C4, but unexpected or unreal climatic zoning was not generated, giving place to a consistent spatial distribution of zones throughout the region. Consequently, the proposed method allows a more accurate climatic zoning of any region in agreement with the Spanish legislation on energy efficiency in buildings, which would enhance the setting of thermal demand rates according to the actual climatic characterisation of the area in which a particular municipality is located.

  16. Effect of water-ice phase change on thermal performance of building materials

    Science.gov (United States)

    Kočí, Václav; Černý, Robert

    2016-07-01

    The effect of water ice-phase change on thermal performance of integrated building material is investigated in this paper. As a characteristic construction, simple external wall made of aerated autoclaved concrete was assumed which was exposed to dynamic climatic condition of Šerák, Czech Republic. The computational modelling of hygrothermal performance was carried out using computer codes HEMOT and SIFEL that work on the basis of finite element method. The effect of phase change was taken into account by fixed-domain method, when experimentally determined effective specific heat capacity was used as a material parameter. It comprises also the effect of heat consumption and heat release that accompany the water-ice phase change. Comparing to the results with specific heat capacity, the effect of phase change on thermal performance could be quantified. The results showed that temperature fields can differ more than 6 °C. Additionally, the amount energy transported through the wall may be higher up to 4 %. This confirmed, that the effect water-ice phase change should be included in all the relevant energy calculations.

  17. Identification of thermal properties distribution in building wall using infrared thermography

    Science.gov (United States)

    Brouns, Jordan; Dumoulin, Jean

    2016-04-01

    [1] L. Ibos, J-P. Monchau, V. Feuillet, Y. Candau, A comparative study of in-situ measurement methods of a building wall thermal resistance using infrared thermography, in Proc. SPIE 9534, Twelfth International Conference on Quality Control by Artificial Vision 2015, 95341I (April 30, 2015); doi:10.1117/12.2185126 [2] Nassiopoulos, A., Bourquin, F., On-site building walls characterization, Numerical Heat Transfer, Part A : Applications, 63(3) :179 :200, 2013 [3] J. Brouns, Développement d'outils numériques pour l'audit énergétique des bâtiments, PhD thesis, Université Paris-Est, SIE, 2014 [4] J.-L. Lions, Contrôle optimal de systèmes gouvernés par des équations aux dérivées partielles. Book, Dunod editor, 1968.

  18. Comparison of CFD simulation of night purge ventilation to full-scale building measurements

    Science.gov (United States)

    Chigurupati, Asha; Gorle, Catherine; Iaccarino, Gianluca

    2014-11-01

    Efforts to improve the understanding of air motion in and around buildings can lead to more efficient natural ventilation systems, thereby significantly reducing a building's heating and cooling demands. CFD simulations enable solving the details of the flow and convective heat transfer in buildings and have the potential to predict the performance of natural ventilation with a high degree of accuracy. Understanding the actual predictive capability of CFD simulations is however complicated by the complexity of the geometry and physics involved, and the uncertainty and variability in the boundary conditions. In the present study we model the night flush process in the Y2E2 building on Stanford University's campus and compare the results to measurements in the full-scale, operational building. We model half of the building, which consists of three floors with office spaces and two atriums. We solve the RANS equations using ANSYS/Fluent and k-e RNG theory turbulence closure model for the duration of one night flush and will present a comparison of the CFD results to measurements of the temperature on each floor in both atriums. Future investigations will focus on the potential of reducing the discrepancy between observed and predicted values by varying uncertain model parameters and boundary conditions.

  19. Stochastic Modeling of Overtime Occupancy and Its Application in Building Energy Simulation and Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kaiyu; Yan, Da; Hong, Tianzhen; Guo, Siyue

    2014-02-28

    Overtime is a common phenomenon around the world. Overtime drives both internal heat gains from occupants, lighting and plug-loads, and HVAC operation during overtime periods. Overtime leads to longer occupancy hours and extended operation of building services systems beyond normal working hours, thus overtime impacts total building energy use. Current literature lacks methods to model overtime occupancy because overtime is stochastic in nature and varies by individual occupants and by time. To address this gap in the literature, this study aims to develop a new stochastic model based on the statistical analysis of measured overtime occupancy data from an office building. A binomial distribution is used to represent the total number of occupants working overtime, while an exponential distribution is used to represent the duration of overtime periods. The overtime model is used to generate overtime occupancy schedules as an input to the energy model of a second office building. The measured and simulated cooling energy use during the overtime period is compared in order to validate the overtime model. A hybrid approach to energy model calibration is proposed and tested, which combines ASHRAE Guideline 14 for the calibration of the energy model during normal working hours, and a proposed KS test for the calibration of the energy model during overtime. The developed stochastic overtime model and the hybrid calibration approach can be used in building energy simulations to improve the accuracy of results, and better understand the characteristics of overtime in office buildings.

  20. Assessment of Extent and Degree of Thermal Damage to Polymeric Materials in the Three Mile Island Unit 2 Reactor Building

    International Nuclear Information System (INIS)

    Thermal damage to susceptible materials in accessible regions of the TMI-2 reactor building shows damage-distribution patterns that indicate non-uniform intensity of exposure. No clear explanation for non-uniformity is found in existing evidence; e.g., in some regions a lack of thermally susceptible materials frustrates analysis. Elsewhere, burned materials are present next to materials that seem similar but appear unscathed-leading to conjecture that the latter materials preferentially absorb water vapor during periods of high local steam concentration. Most of the polar crane pendant shows heavy burns on one half of its circumferential surface. This evidence suggests that the polar crane pendant side that experienced heaviest burn damage was exposed to intense radiant energy from a transient fire plume in the reactor containment volume. Tests and simple heat-transfer calculations based on pressure and temperature records from the accident show that the atmosphere inside the reactor building was probably 8% hydrogen in air, a value not inconsistent with the extent of burn damage. Burn-pattern geography indicates uniform thermal exposure in the dome volume to the 406-ft level (about 6 ft below the polar crane girder), partial thermal exposure in the volume between the 406- and 347-ft levels as indicated by the polar crane cable, and lack of damage to most thermally susceptible materials in the west quadrant of the reactor building; some evidence of thermal exposure Is seen in the free volume between the 305- and 347-ft levels. (author)