A Policy study on stabilization of heating oil supply and demand

Energy Technology Data Exchange (ETDEWEB)

Lee, Bok Jae [Korea Energy Economics Institute, Euiwang (Korea)

1999-03-01

As a principal heating fuel for household and commercial sector, and a heat source fuel for industry, the heating oil shows its great demand intensively during a specific period (wintertime) due to its characteristics. It represents that the fluctuation of heating oil demand throughout the year is very extreme. Therefore, the stable supply of heating oil has been rising as an important task. It is desirable to develop and supply a new type of heating oil compounded of kerosene and gasoline with appropriate ratio for short- and mid-term to have a stable supply and demand of heating oil. For long-term prospect, it is desirable to supply petroleum products mixing gasoline and B-C oil as heating oil when it is equipped with combustion technology of boiler and distribution system. In this case, it is required to have investment on infrastructure for the supply of new heating oil (mixture of gasoline and B-C oil) and a proper preparatory period for the conversion of equipment (such as a boiler). The vitalization of storing oil is essential to stabilize the supply and demand of heating oil. In order to vitalize it, the price of heating oil should be determined by a market function reflecting the seasonal supply and demand circumstances. (author). 101 refs., 5 figs., 83 tabs.

Heat demand mapping and district heating grid expansion analysis: Case study of Velika Gorica

Directory of Open Access Journals (Sweden)

Dorotić Hrvoje

2017-01-01

Full Text Available Highly efficient cogeneration and district heating systems have a significant potential for primary energy savings and the reduction of greenhouse gas emissions through the utilization of a waste heat and renewable energy sources. These potentials are still highly underutilized in most European countries. They also play a key role in the planning of future energy systems due to their positive impact on the increase of integration of intermittent renewable energy sources, for example wind and solar in a combination with power to heat technologies. In order to ensure optimal levels of district heating penetration into an energy system, a comprehensive analysis is necessary to determine the actual demands and the potential energy supply. Economical analysis of the grid expansion by using the GIS based mapping methods hasn’t been demonstrated so far. This paper presents a heat demand mapping methodology and the use of its output for the district heating network expansion analysis. The result are showing that more than 59% of the heat demand could be covered by the district heating in the city of Velika Gorica, which is two times more than the present share. The most important reason of the district heating's unfulfilled potential is already existing natural gas infrastructure.

Heat demand mapping and district heating grid expansion analysis: Case study of Velika Gorica

Science.gov (United States)

Dorotić, Hrvoje; Novosel, Tomislav; Duić, Neven; Pukšec, Tomislav

2017-10-01

Highly efficient cogeneration and district heating systems have a significant potential for primary energy savings and the reduction of greenhouse gas emissions through the utilization of a waste heat and renewable energy sources. These potentials are still highly underutilized in most European countries. They also play a key role in the planning of future energy systems due to their positive impact on the increase of integration of intermittent renewable energy sources, for example wind and solar in a combination with power to heat technologies. In order to ensure optimal levels of district heating penetration into an energy system, a comprehensive analysis is necessary to determine the actual demands and the potential energy supply. Economical analysis of the grid expansion by using the GIS based mapping methods hasn't been demonstrated so far. This paper presents a heat demand mapping methodology and the use of its output for the district heating network expansion analysis. The result are showing that more than 59% of the heat demand could be covered by the district heating in the city of Velika Gorica, which is two times more than the present share. The most important reason of the district heating's unfulfilled potential is already existing natural gas infrastructure.

Electricity demand profile with high penetration of heat pumps in Nordic area

DEFF Research Database (Denmark)

Liu, Zhaoxi; Wu, Qiuwei; Nielsen, Arne Hejde

2013-01-01

This paper presents the heat pump (HP) demand profile with high HP penetration in the Nordic area in order to achieve the carbon neutrality power system. The calculation method in the European Standard EN14825 was used to estimate the HP electricity demand profile. The study results show...... there will be high power demand from HPs and the selection of supplemental heating for heat pumps has a big impact on the peak electrical power load of heating. The study in this paper gives an estimate of the scale of the electricity demand with high penetration of heat pumps in the Nordic area....

Energy efficiency policies for space heating in EU countries: A panel data analysis for the period 1990–2010

International Nuclear Information System (INIS)

Ó Broin, Eoin; Nässén, Jonas; Johnsson, Filip

2015-01-01

Highlights: • Space heating demand between 1990 and 2010 modelled using a panel of 14 EU countries. • The impacts of 260 efficiency polices affecting space heating demand are examined. • Regulatory policies found to have had a greater success than financial or informative. • High priority should be given to regulatory policies for space heating energy goals. - Abstract: We present an empirical analysis of the more than 250 space heating-focused energy efficiency policies that have been in force at the EU and national levels in the period 1990–2010. This analysis looks at the EU-14 residential sector (Pre-2004 EU-15, excluding Luxembourg) using a panel data regression analysis on unit consumption of energy for space heating (kWh/m 2 /year). The policies are represented as a regression variable using a semi-quantitative impact estimation obtained from the MURE Policy Database. The impacts of the policies as a whole, and subdivided into financial, regulatory, and informative policies, are examined. The correlation between the actual reductions in demand and the estimated impact of regulatory policies is found to be stronger than the corresponding correlations with the respective impacts of financial policies and informative polices. Together with the well-known market barriers to energy efficiency that exist in the residential sector, these findings suggest that regulatory policy measures be given a high priority in the design of an effective pathway towards the EU-wide goals for space heating energy

Space Heating Equipment

Energy Technology Data Exchange (ETDEWEB)

Rafferty, Kevin D.

1998-01-01

The performance evaluation of space heating equipment for a geothermal application is generally considered from either of two perspectives: (a) selecting equipment for installation in new construction, or (b) evaluating the performance and retrofit requirements of an existing system. With regard to new construction, the procedure is relatively straightforward. Once the heating requirements are determined, the process need only involve the selection of appropriately sized hot water heating equipment based on the available water temperature. It is important to remember that space heating equipment for geothermal applications is the same equipment used in non-geothermal applications. What makes geothermal applications unique is that the equipment is generally applied at temperatures and flow rates that depart significantly from traditional heating system design. This chapter presents general considerations for the performance of heating equipment at non-standard temperature and flow conditions, retrofit of existing systems, and aspects of domestic hot water heating.

Simple future weather files for estimating heating and cooling demand

DEFF Research Database (Denmark)

Cox, Rimante Andrasiunaite; Drews, Martin; Rode, Carsten

2015-01-01

useful estimates of future energy demand of a building. Experimental results based on both the degree-day method and dynamic simulations suggest that this is indeed the case. Specifically, heating demand estimates were found to be within a few per cent of one another, while estimates of cooling demand...... were slightly more varied. This variation was primarily due to the very few hours of cooling that were required in the region examined. Errors were found to be most likely when the air temperatures were close to the heating or cooling balance points, where the energy demand was modest and even...... relatively large errors might thus result in only modest absolute errors in energy demand....

Heat demand profiles of energy conservation measures in buildings and their impact on a district heating system

International Nuclear Information System (INIS)

Lundström, Lukas; Wallin, Fredrik

2016-01-01

Highlights: • Energy savings impact on an low CO 2 emitting district heating system. • Heat profiles of eight building energy conservation measures. • Exhaust air heat pump, heat recovery ventilation, electricity savings etc. • Heat load weather normalisation with segmented multivariable linear regression. - Abstract: This study highlights the forthcoming problem with diminishing environmental benefits from heat demand reducing energy conservation measures (ECM) of buildings within district heating systems (DHS), as the supply side is becoming “greener” and more primary energy efficient. In this study heat demand profiles and annual electricity-to-heat factors of ECMs in buildings are computed and their impact on system efficiency and greenhouse gas emissions of a Swedish biomass fuelled and combined heat and power utilising DHS are assessed. A weather normalising method for the DHS heat load is developed, combining segmented multivariable linear regressions with typical meteorological year weather data to enable the DHS model and the buildings model to work under the same weather conditions. Improving the buildings’ envelope insulation level and thereby levelling out the DHS heat load curve reduces greenhouse gas emissions and improves primary energy efficiency. Reducing household electricity use proves to be highly beneficial, partly because it increases heat demand, allowing for more cogeneration of electricity. However the other ECMs considered may cause increased greenhouse gas emissions, mainly because of their adverse impact on the cogeneration of electricity. If biomass fuels are considered as residuals, and thus assigned low primary energy factors, primary energy efficiency decreases when implementing ECMs that lower heat demand.

A Danish Heat Atlas for Supply Strategies and Demand Side Management

DEFF Research Database (Denmark)

Möller, Bernd

The expansion of district heating, the assessment of the impact of heat supply strategies, as well as the analysis of significant heat demand savings require sound decision support at high detail. Data is needed to continuously quantify potentials and costs of measures in the end-use and supply...... heat demand and possible savings. The location of each building relative to heat supply technologies is mapped and used for the assessment of supply strategies by potentials, costs and environmental impact. Both elements can furthermore be used to balance investments in supply with investments...

The potential reduction of household space heating CO2 emissions in the Netherlands

NARCIS (Netherlands)

Engelmoer, Wiebe

2011-01-01

SUMMARY Space heating is responsible for more than half of the total Dutch household energy demand, a large share is based on natural gas. With increasing concern about global warming and depleting gas reserves, energy saving has become an important topi

Decreasing of energy consumption for space heating in existing residential buildings; Combined geothermal and gas district heating systems

International Nuclear Information System (INIS)

Rosca, Marcel

2000-01-01

The City of Oradea, Romania, has a population of about 230 000 inhabitants. Almost 70% of the total heat demand, including industrial, is supplied by a classical East European type district heating system. The heat is supplied by two low grade coal fired co-generation power plants. The oldest distribution networks and substitutions, as well as one power plant, are 35 years old and require renovation or even reconstruction. The geothermal reservoir located under the city supplies at present 2,2% of the total heat demand. By generalizing the reinjection, the production can be increased to supply about 8% of the total heat demand, without any significant reservoir pressure or temperature decline over 25 years. Another potential energy source is natural gas, a main transport pipeline running close to the city. Two possible scenarios are envisaged to replace the low grade coal by natural gas and geothermal energy as heat sources for Oradea. In one scenario, the geothermal energy supplies the heat for tap water heating and the base load for space heating in a limited number of substations, with peak load being produced by natural gas fired boilers. In the other scenario, the geothermal energy is only used for tap water heating. In both scenarios, all substations are converted into heat plants, natural gas being the main energy source. The technical, economic, and environmental assessment of the two proposed scenarios are compared with each other, as well as with the existing district heating system. Two other possible options, namely to renovate and convert the existing co-generation power plants to natural gas fired boilers or to gas turbines, are only briefly discussed, being considered unrealistic, at least for the short and medium term future. (Author)

Demand side management for commercial buildings using an in line heat pump water heating methodology

International Nuclear Information System (INIS)

Rankin, Riaan; Rousseau, Pieter G.; Eldik, Martin van

2004-01-01

Most of the sanitary hot water used in South African buildings is heated by means of direct electrical resistance heaters. This is one of the major contributors to the undesirably high morning and afternoon peaks imposed on the national electricity supply grid. For this reason, water heating continues to be of concern to the electricity supplier, ESCOM. Previous studies, conducted by the Potchefstroom University for Christian Higher Education in South Africa, indicated that extensive application of the so called inline heat pump water heating methodology in commercial buildings could result in significant demand side management savings to ESKOM. Furthermore, impressive paybacks can be obtained by building owners who choose to implement the design methodology on existing or new systems. Currently, a few examples exist where the design methodology has been successfully implemented. These installations are monitored with a fully web centric monitoring system that allows 24 h access to data from each installation. Based on these preliminary results, a total peak demand reduction of 108 MW can be achieved, which represents 18% of the peak load reduction target set by ESKOM until the year 2015. This represents an avoided cost of approximately MR324 (ZAR) [Int J Energy Res 25(4) (1999) 2000]. Results based on actual data from the monitored installations shows a significant peak demand reduction for each installation. In one installation, a hotel with an occupancy of 220 people, the peak demand contribution of the hot water installation was reduced by 86%, realizing a 36% reduction in peak demand for the whole building. The savings incurred by the building owner also included significant energy consumption savings due to the superior energy efficiency of the heat pump water heater. The combined savings result in a conservatively calculated straight payback period of 12.5 months, with an internal rate of return of 98%. The actual cost of water heating is studied by

The potential demand for bioenergy in residential heating applications (bio-heat) in the UK based on a market segment analysis

International Nuclear Information System (INIS)

Jablonski, S.; Pantaleo, A.; Bauen, A.; Pearson, P.; Panoutsou, C.; Slade, R.

2008-01-01

How large is the potential demand for bio-heat in the UK? Whilst most research has focused on the supply of biomass for energy production, an understanding of the potential demand is crucial to the uptake of heat from bioenergy. We have designed a systematic framework utilising market segmentation techniques to assess the potential demand for biomass heat in the UK. First, the heat market is divided into relevant segments, characterised in terms of their final energy consumption, technological and fuel supply options. Second, the key technical, economic and organisational factors that affect the uptake of bioenergy in each heat segment are identified, classified and then analysed to reveal which could be strong barriers, which could be surmounted easily, and for which bioenergy heat represents an improvement compared to alternatives. The defined framework is applied to the UK residential sector. We identify provisionally the most promising market segments for bioenergy heat, and their current levels of energy demand. We find that, depending on the assumptions, the present potential demand for bio-heat in the UK residential sector ranges between 3% (conservative estimate) and 31% (optimistic estimate) of the total energy consumed in the heat market. (author)

Evaluation of a multiple linear regression model and SARIMA model in forecasting heat demand for district heating system

International Nuclear Information System (INIS)

Fang, Tingting; Lahdelma, Risto

2016-01-01

Highlights: • Social factor is considered for the linear regression models besides weather file. • Simultaneously optimize all the coefficients for linear regression models. • SARIMA combined with linear regression is used to forecast the heat demand. • The accuracy for both linear regression and time series models are evaluated. - Abstract: Forecasting heat demand is necessary for production and operation planning of district heating (DH) systems. In this study we first propose a simple regression model where the hourly outdoor temperature and wind speed forecast the heat demand. Weekly rhythm of heat consumption as a social component is added to the model to significantly improve the accuracy. The other type of model is the seasonal autoregressive integrated moving average (SARIMA) model with exogenous variables as a combination to take weather factors, and the historical heat consumption data as depending variables. One outstanding advantage of the model is that it peruses the high accuracy for both long-term and short-term forecast by considering both exogenous factors and time series. The forecasting performance of both linear regression models and time series model are evaluated based on real-life heat demand data for the city of Espoo in Finland by out-of-sample tests for the last 20 full weeks of the year. The results indicate that the proposed linear regression model (T168h) using 168-h demand pattern with midweek holidays classified as Saturdays or Sundays gives the highest accuracy and strong robustness among all the tested models based on the tested forecasting horizon and corresponding data. Considering the parsimony of the input, the ease of use and the high accuracy, the proposed T168h model is the best in practice. The heat demand forecasting model can also be developed for individual buildings if automated meter reading customer measurements are available. This would allow forecasting the heat demand based on more accurate heat consumption

Optimal Energy Management of Combined Cooling, Heat and Power in Different Demand Type Buildings Considering Seasonal Demand Variations

Directory of Open Access Journals (Sweden)

Akhtar Hussain

2017-06-01

Full Text Available In this paper, an optimal energy management strategy for a cooperative multi-microgrid system with combined cooling, heat and power (CCHP is proposed and has been verified for a test case of building microgrids (BMGs. Three different demand types of buildings are considered and the BMGs are assumed to be equipped with their own combined heat and power (CHP generators. In addition, the BMGs are also connected to an external energy network (EEN, which contains a large CHP, an adsorption chiller (ADC, a thermal storage tank, and an electric heat pump (EHP. By trading the excess electricity and heat energy with the utility grid and EEN, each BMG can fulfill its energy demands. Seasonal energy demand variations have been evaluated by selecting a representative day for the two extreme seasons (summer and winter of the year, among the real profiles of year-round data on electricity, heating, and cooling usage of all the three selected buildings. Especially, the thermal energy management aspect is emphasized where, bi-lateral heat trading between the energy supplier and the consumers, so-called energy prosumer concept, has been realized. An optimization model based on mixed integer linear programming has been developed for minimizing the daily operation cost of the EEN while fulfilling the energy demands of the BMGs. Simulation results have demonstrated the effectiveness of the proposed strategy.

A method of determining the thermal power demand of buildings connected to the district heating system with usage of heat accumulation

Directory of Open Access Journals (Sweden)

Turski Michał

2017-01-01

Full Text Available The paper presents a new method of determining the thermal power demand of buildings connected to the district heating system, which included the actual heat demand and the possibility of balancing the thermal power using the thermal storage capacity of district heating network and internal heat capacity of buildings. Moreover, the analysis of the effect of incidence of external air temperature and duration of episodes with the lowest outdoor temperatures on the thermal power demand of district heating system was conducted.

Quantifying demand flexibility of power-to-heat and thermal energy storage in the control of building heating systems

DEFF Research Database (Denmark)

Finck, Christian; Li, Rongling; Kramer, Rick

2018-01-01

restricted by power-to-heat conversion such as heat pumps and thermal energy storage possibilities of a building. To quantify building demand flexibility, it is essential to capture the dynamic response of the building energy system with thermal energy storage. To identify the maximum flexibility a building......’s energy system can provide, optimal control is required. In this paper, optimal control serves to determine in detail demand flexibility of an office building equipped with heat pump, electric heater, and thermal energy storage tanks. The demand flexibility is quantified using different performance...... of TES and power-to-heat in any case of charging, discharging or idle mode. A simulation case study is performed showing that a water tank, a phase change material tank, and a thermochemical material tank integrated with building heating system can be designed to provide flexibility with optimal control....

Geospatial Analysis of the Building Heat Demand and Distribution Losses in a District Heating Network

Directory of Open Access Journals (Sweden)

Tobias Törnros

2016-11-01

Full Text Available The district heating (DH demand of various systems has been simulated in several studies. Most studies focus on the temporal aspects rather than the spatial component. In this study, the DH demand for a medium-sized DH network in a city in southern Germany is simulated and analyzed in a spatially explicit approach. Initially, buildings are geo-located and attributes obtained from various sources including building type, ground area, and number of stories are merged. Thereafter, the annual primary energy demand for heating and domestic hot water is calculated for individual buildings. Subsequently, the energy demand is aggregated on the segment level of an existing DH network and the water flow is routed through the system. The simulation results show that the distribution losses are overall the highest at the end segments (given in percentage terms. However, centrally located pipes with a low throughflow are also simulated to have high losses. The spatial analyses are not only useful when addressing the current demand. Based on a scenario taking into account the refurbishment of buildings and a decentralization of energy production, the future demand was also addressed. Due to lower demand, the distribution losses given in percentage increase under such conditions.

Heat transfer capability analysis of heat pipe for space reactor

International Nuclear Information System (INIS)

Li Huaqi; Jiang Xinbiao; Chen Lixin; Yang Ning; Hu Pan; Ma Tengyue; Zhang Liang

2015-01-01

To insure the safety of space reactor power system with no single point failures, the reactor heat pipes must work below its heat transfer limits, thus when some pipes fail, the reactor could still be adequately cooled by neighbor heat pipes. Methods to analyze the reactor heat pipe's heat transfer limits were presented, and that for the prevailing capillary limit analysis was improved. The calculation was made on the lithium heat pipe in core of heat pipes segmented thermoelectric module converter (HP-STMC) space reactor power system (SRPS), potassium heat pipe as radiator of HP-STMC SRPS, and sodium heat pipe in core of scalable AMTEC integrated reactor space power system (SAIRS). It is shown that the prevailing capillary limits of the reactor lithium heat pipe and sodium heat pipe is 25.21 kW and 14.69 kW, providing a design margin >19.4% and >23.6%, respectively. The sonic limit of the reactor radiator potassium heat pipe is 7.88 kW, providing a design margin >43.2%. As the result of calculation, it is concluded that the main heat transfer limit of HP-STMC SRPS lithium heat pipe and SARIS sodium heat pipe is prevailing capillary limit, but the sonic limit for HP-STMC SRPS radiator potassium heat pipe. (authors)

Estimating end-use emissions factors for policy analysis: the case of space cooling and heating.

Science.gov (United States)

Jacobsen, Grant D

2014-06-17

This paper provides the first estimates of end-use specific emissions factors, which are estimates of the amount of a pollutant that is emitted when a unit of electricity is generated to meet demand from a specific end-use. In particular, this paper provides estimates of emissions factors for space cooling and heating, which are two of the most significant end-uses. The analysis is based on a novel two-stage regression framework that estimates emissions factors that are specific to cooling or heating by exploiting variation in cooling and heating demand induced by weather variation. Heating is associated with similar or greater CO2 emissions factor than cooling in all regions. The difference is greatest in the Midwest and Northeast, where the estimated CO2 emissions factor for heating is more than 20% larger than the emissions factor for cooling. The minor differences in emissions factors in other regions, combined with the substantial difference in the demand pattern for cooling and heating, suggests that the use of overall regional emissions factors is reasonable for policy evaluations in certain locations. Accurately quantifying the emissions factors associated with different end-uses across regions will aid in designing improved energy and environmental policies.

Optimisation of a Swedish district heating system with reduced heat demand due to energy efficiency measures in residential buildings

International Nuclear Information System (INIS)

Åberg, M.; Henning, D.

2011-01-01

The development towards more energy efficient buildings, as well as the expansion of district heating (DH) networks, is generally considered to reduce environmental impact. But the combined effect of these two progressions is more controversial. A reduced heat demand (HD) due to higher energy efficiency in buildings might hamper co-production of electricity and DH. In Sweden, co-produced electricity is normally considered to displace electricity from less efficient European condensing power plants. In this study, a potential HD reduction due to energy efficiency measures in the existing building stock in the Swedish city Linköping is calculated. The impact of HD reduction on heat and electricity production in the Linköping DH system is investigated by using the energy system optimisation model MODEST. Energy efficiency measures in buildings reduce seasonal HD variations. Model results show that HD reductions primarily decrease heat-only production. The electricity-to-heat output ratio for the system is increased for HD reductions up to 30%. Local and global CO 2 emissions are reduced. If co-produced electricity replaces electricity from coal-fired condensing power plants, a 20% HD reduction is optimal for decreasing global CO 2 emissions in the analysed DH system. - Highlights: ► A MODEST optimisation model of the Linköping district heating system is used. ► The impact of heat demand reduction on heat and electricity production is examined. ► Model results show that heat demand reductions decrease heat-only production. ► Local and global CO 2 emissions are reduced. ► The system electricity-to-heat output increases for reduced heat demand up to 30%.

Energy demand: Facts and trends

Energy Technology Data Exchange (ETDEWEB)

Chateau, B; Lapillonne, B

1982-01-01

The relationship between economic development and energy demand is investigated in this book. It gives a detailed analysis of the energy demand dynamics in industrialized countries and compares the past evolution of the driving factors behind energy demand by sector and by end-uses for the main OECD countries: residential sector (space heating, water heating, cooking...), tertiary sector, passenger and goods transport by mode, and industry (with particular emphasis on the steel and cement industry). This analysis leads to a more precise understanding of the long-term trends of energy demand; highlighting the influence on these trends of energy prices, especially after the oil price shocks, and of the type of economic development pattern.

Chapter 12. Space Heating Equipment

Energy Technology Data Exchange (ETDEWEB)

Rafferty, Kevin D.

1998-01-01

The performance evaluation of space heating equipment for a geothermal application is generally considered from either of two perspectives: (a) selecting equipment for installation in new construction, or (b) evaluating the performance and retrofit requirements of an existing system. With regard to new construction, the procedure is relatively straightforward. Once the heating requirements are determined, the process need only involve the selection of appropriately sized hot water heating equipment based on the available water temperature. It is important to remember that space heating equipment for geothermal applications is the same equipment used in non-geothermal applications. What makes geothermal applications unique is that the equipment is generally applied at temperatures and flow rates that depart significantly from traditional heating system design. This chapter presents general considerations for the performance of heating equipment at non-standard temperature and flow conditions, retrofit of existing systems, and aspects of domestic hot water heating.

More Wind Power Integration with Adjusted Energy Carriers for Space Heating in Northern China

Directory of Open Access Journals (Sweden)

Jianjun He

2012-08-01

Full Text Available In Northern China, due to the high penetration of coal-fired cogeneration facilities, which are generally equipped with extraction-condensing steam turbines, lots of wind power resources may be wasted during the heating season. In contrast, considerable coal is consumed in the power generation sector. In this article, firstly it is revealed that there exists a serious divergence in the ratio of electrical to thermal energy between end users’ demand and the cogenerations’ production during off-peak load at night, which may negate active power-balancing of the electric power grid. Secondly, with respect to this divergence only occurring during off-peak load at night, a temporary proposal is given so as to enable the integration of more wind power. The authors suggest that if the energy carrier for part of the end users’ space heating is switched from heating water to electricity (e.g., electric heat pumps (EHPs can provide space heating in the domestic sector, the ratio of electricity to heating water load should be adjusted to optimize the power dispatch between cogeneration units and wind turbines, resulting in fuel conservation. With this proposal, existing infrastructures are made full use of, and no additional ones are required. Finally a numerical simulation is performed in order to illustrate both the technical and economic feasibility of the aforementioned proposal, under ongoing infrastructures as well as electricity and space heating tariff conditions without changing participants’ benefits. The authors aim to persuade Chinese policy makers to enable EHPs to provide space heating to enable the integration of more wind power.

Determinants of residential space heating expenditures in Great Britain

Energy Technology Data Exchange (ETDEWEB)

Meier, Helena [Department of Economics, University of Hamburg, Von Melle Park 5, 20146 Hamburg (Germany); Rehdanz, Katrin [Department of Economics, University of Kiel, Olshausenstrasse 40, 24118 Kiel (Germany)

2010-09-15

In Great Britain, several policy measures have been implemented in order to increase energy efficiency and reduce carbon emissions. In the domestic sector, this could, for example, be achieved by improving space heating efficiency and thus decreasing heating expenditure. However, in order to efficiently design and implement such policy measures, a better understanding of the determinants affecting heating expenditure is needed. In this paper we examine the following determinants: socio-economic factors, building characteristics, heating technologies and weather conditions. In contrast to most other studies we use panel data to investigate household demand for heating in Great Britain. Our data sample is the result of an annual set of interviews with more than 5000 households, starting in 1991 and ending in 2005. The sample represents a total of 64,000 observations over the fifteen-year period. Our aim is to derive price and income elasticities both for Britain as a whole and for different types of household. Our results suggest that differences exist between owner-occupied and renter households. These households react differently to changes in income and prices. Our results also imply that a number of socio-economic criteria have a significant influence on heating expenditure, independently of the fuel used for heating. Understanding the impacts of different factors on heating expenditure and impact differences between types of household is helpful in designing target-oriented policy measures. (author)

The demand function for residential heat through district heating system and its consumption benefits in Korea

International Nuclear Information System (INIS)

Lim, Seul-Ye; Kim, Hyo-Jin; Yoo, Seung-Hoon

2016-01-01

The demand for residential heat (RH) through a district heating system (DHS) has been and will be expanded in Korea due to its better performance in energy efficiency and the abatement of greenhouse gas emissions than decentralized boilers. The purposes of this paper are two-fold. The first is to obtain the demand function for DHS-based RH in Korea and investigate the price and income elasticities of the demand employing the quarterly data covering the period 1988–2013. The short-run price and income elasticities are estimated as −0.700 and 0.918, respectively. Moreover, the long-run elasticities are −1.253 and 1.642, respectively. The second purpose is to measure the consumption benefits of DHS-based-RH employing the economic theory that they are the sum of the actual payment and consumer surplus for the consumption. Considering that the average price and estimated consumer surplus of the DHS-based RH use in 2013 are computed to be KRW 87,870 (USD 84.1) and KRW 62,764 (USD 60.1) per Gcal, the consumption benefits of the DHS-based RH are calculated to be KRW 150,634 (USD 144.2) per Gcal. This information can be beneficially utilized to conduct an economic feasibility study for a new DHS project related to RH supply. - Highlights: • Demand for residential heat (RH) from district heating system (DHS) is expanding. • We estimate the demand function for and consumption benefits of DHS-based RH. • Short-run price and income elasticities are −0.700 and 0.918, respectively. • Long-run price and income elasticities are −1.253 and 1.642, respectively. • Consumption benefits of DHS-based RH are KRW 150,634 (USD 144.2) per Gcal.

Real-time appraisal of the spatially distributed heat related health risk and energy demand of cities

Science.gov (United States)

Keramitsoglou, Iphigenia; Kiranoudis, Chris T.; Sismanidis, Panagiotis

2016-08-01

The Urban Heat Island (UHI) is an adverse environmental effect of urbanization that increases the energy demand of cities, impacts the human health, and intensifies and prolongs heatwave events. To facilitate the study of UHIs the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing of the National Observatory of Athens (IAASARS/NOA) has developed an operational real-time system that exploits remote sensing image data from Meteosat Second Generation - Spinning Enhanced Visible and Infrared Imager (MSG-SEVIRI) and generates high spatiotemporal land surface temperature (LST) and 2 m air temperature (TA) time series. These datasets form the basis for the generation of higher value products and services related to energy demand and heat-related health issues. These products are the heatwave hazard (HZ); the HUMIDEX (i.e. an index that describes the temperature felt by an individual exposed to heat and humidity); and the cooling degrees (CD; i.e. a measure that reflects the energy needed to cool a building). The spatiotemporal characteristics of HZ, HUMIDEX and CD are unique (1 km/5 min) and enable the appraisal of the spatially distributed heat related health risk and energy demand of cities. In this paper, the real time generation of the high spatiotemporal HZ, HUMIDEX and CD products is discussed. In addition, a case study corresponding to Athens' September 2015 heatwave is presented so as to demonstrate their capabilities. The overall aim of the system is to provide high quality data to several different end users, such as health responders, and energy suppliers. The urban thermal monitoring web service is available at http://snf-652558.vm.okeanos.grnet.gr/treasure/portal/info.html.

Heat Conduction of Air in Nano Spacing

Directory of Open Access Journals (Sweden)

Zhang Yao-Zhong

2009-01-01

Full Text Available Abstract The scale effect of heat conduction of air in nano spacing (NS is very important for nanodevices to improve their life and efficiency. By constructing a special technique, the changes of heat conduction of air were studied by means of measuring the heat conduction with heat conduction instrument in NS between the hot plate and the cooling plate. Carbon nanotubes were used to produce the nano spacing. The results show that when the spacing is small down to nanometer scale, heat conduction plays a prominent role in NS. It was found that the thickness of air is a non-linear parameter for demarcating the heat conduction of air in NS and the rate of heat conduction in unit area could be regard as a typical parameter for the heat conduction characterization at nanometer scale.

Effective Management of High-Use/High-Demand Space Using Restaurant-Style Pagers

Science.gov (United States)

Gonzalez, Adriana

2012-01-01

The library landscape is changing at a fast pace, with an increase in the demand for study space including quiet, individualized study space; open group study space; and as enclosed group study space. In large academic libraries, managing limited high-demand resources is crucial and is partially being driven by the greater emphasis on group…

Generation of Domestic Hot Water, Space Heating and Driving Pattern Profiles for Integration Analysis of Active Loads in Low Voltage Grids

DEFF Research Database (Denmark)

Diaz de Cerio Mendaza, Iker; Pigazo, Alberto; Bak-Jensen, Birgitte

2013-01-01

at household level. Despite of the well-known flexible service that this kind of loads can provide, their flexibility is highly dependent of the domestic hot water and space heating demand and the driving habits of each user. This paper presents two methodologies employed to randomly generate thermal power......The changes in the Danish energy sector, consequence of political agreements, are expected to have direct impact in the actual power distribution systems. Large number of electric boiler, heat pumps and electric vehicles are planned and will cope large percentage of the future power consumption...... demand and electric vehicle driving profiles, to be used for power grid calculations. The generated thermal profiles relied on a statistical analysis made from real domestic hot water and space heating data from 25 households of a typical Danish residential area. The driving profiles instead were formed...

Field evaluation and assessment of thermal energy storage for residential space heating

Science.gov (United States)

Hersh, H. N.

1982-02-01

A data base was developed based on two heating seasons and 45 test and 30 control homes in Maine and Vermont. Based on first analysis of monitored temperatures and electrical energy used for space heating, fuel bills and reports of users and utilities, the technical performance of TES ceramic and hydronic systems is deemed to be technically satisfactory and there is a high degree of customer acceptance and positive attitudes towards TES. Analysis of house data shows a high degree of variability in electric heat energy demand for a given degree-day. An analysis is underway to investigate relative differences in the efficiency of electricity utilization of storage and direct heating devices. The much higher price of storge systems relative to direct systems is an impediment to market penetration. A changing picture of rate structures may encourage direct systems at the expense of storage systems.

Compact seasonal PCM heat storage for solar heating systems

DEFF Research Database (Denmark)

Dannemand, Mark

Space heating of buildings and preparation of domestic hot water accounts for a large part of the society’s energy consumption. Solar radiation is an abundant and renewable energy source which can be harvested by solar collectors and used to cover heating demands in the built environment....... The seasonal availability of solar energy does however not match with the heating demands in buildings which typically are large in winter periods when limited solar energy is available. Heat can be stored over a few days in water stores but continuous heat losses limits the storage periods. The possibility...... of storing heat from summer where solar energy is widely available to winter periods where the heating demands are large, allows for implementing more renewable energy in our energy system. The phase change material (PCM) sodium acetate trihydrate (SAT) melts at 58 °C. The melting process requires...

Heat pumps in urban space heating systems: Energy and environmental aspects

International Nuclear Information System (INIS)

Carlini, M.; Impero Abenavoli, R.; Rome Univ. La Sapienza

1991-01-01

A statistical survey is conducted of air pollution in the city of Rome (Italy) due to conventional building space heating systems burning fossil fuels. The survey identifies the annual consumption of the different fuels and the relative amounts of the various pollutants released into the atmosphere by the heating plants, e.g., sulfur and nitrogen oxides, carbon monoxide, etc. Comparisons are then made between the ratios of urban heating plant air pollutants produced per tonne of fuel employed and those for ENEL (Italian National Electricity Board) coal, oil and natural gas fired power plants, in order to demonstrate the better environmental performances of the utility operated energy plants. The building space heating system energy consumption and pollution data are then used in a cost benefit analysis favouring the retrofitting of conventional heating systems with heat pump systems to obtain substantial reductions in energy consumption, heating bills and urban air pollution. The use of readily available, competitively priced and low polluting (in comparison with fuel oil and coal) methane as the energy source for space heating purposes is recommended. The paper also notes the versatility of the heat pump systems in that they could also be used for summer air conditioning

Low-Cost Gas Heat Pump for Building Space Heating

Energy Technology Data Exchange (ETDEWEB)

Garrabrant, Michael [Stone Mountain Technologies, Inc., Johnson City, TN (United States); Keinath, Christopher [Stone Mountain Technologies, Inc., Johnson City, TN (United States)

2016-10-11

Gas-fired residential space heating in the U.S is predominantly supplied by furnaces and boilers. These technologies have been approaching their thermodynamic limit over the past 30 years and improvements for high efficiency units have approached a point of diminishing return. Electric heat pumps are growing in popularity but their heating performance at low ambient temperatures is poor. The development of a low-cost gas absorption heat pump would offer a significant improvement to current furnaces and boilers, and in heating dominated climate zones when compared to electric heat pumps. Gas absorption heat pumps (GAHP) exceed the traditional limit of thermal efficiency encountered by typical furnaces and boilers, and maintain high levels of performance at low ambient temperatures. The project team designed and demonstrated two low-cost packaged prototype GAHP space heating systems during the course of this investigation. Led by Stone Mountain Technologies Inc. (SMTI), with support from A.O. Smith, and the Gas Technology Institute (GTI), the cross-functional team completed research and development tasks including cycle modeling, 8× scaling of a compact solution pump, combustion system development, breadboard evaluation, fabrication of two packaged prototype units, third party testing of the first prototype, and the evaluation of cost and energy savings compared to high and minimum efficiency gas options. Over the course of the project and with the fabrication of two Alpha prototypes it was shown that this technology met or exceeded most of the stated project targets. At ambient temperatures of 47, 35, 17 and -13°F the prototypes achieved gas based coefficients of performance of 1.50, 1.44, 1.37, and 1.17, respectively. Both units operated with parasitic loads well below the 750 watt target with the second Alpha prototype operating 75-100 watts below the first Alpha prototype. Modulation of the units at 4:1 was achieved with the project goal of 2:1 modulation

Causes of Potential Urban Heat Island Space Using Heat flux Budget Under Urban Canopy

Science.gov (United States)

Kwon, Y. J.; Lee, D. K.

2017-12-01

Raised concerns about possible contribution from urban heat island to global warming is about 30 percent. Therefore, mitigating urban heat island became one of major issues to solve among urban planners, urban designers, landscape architects, urban affair decision makers and etc. Urban heat island effect on a micro-scale is influenced by factors such as wind, water vapor and solar radiation. Urban heat island effect on a microscale is influenced by factors like wind, water vapor and solar radiation. These microscopic climates are also altered by factors affecting the heat content in space, like SVF and aspect ratio depending on the structural characteristics of various urban canyon components. Indicators of heat mitigation in urban design stage allows us to create a spatial structure considering the heat balance budget. The spatial characteristics affect thermal change by varying heat storage, emitting or absorbing the heat. The research defines characteristics of the space composed of the factors affecting the heat flux change as the potential urban heat island space. Potential urban heat island spaces are that having higher heat flux than periphery space. The study is to know the spatial characteristics that affects the subsequent temperature rise by the heat flux. As a research method, four types of potential heat island space regions were analyzed. I categorized the spatial types by comparing parameters' value of energy balance in day and night: 1) day severe areas, 2) day comfort areas, 3) night severe areas, 4) night comfort areas. I have looked at these four types of potential urban heat island areas from a microscopic perspective and investigated how various forms of heat influences on higher heat flux areas. This research was designed to investigate the heat indicators to be reflected in the design of urban canyon for heat mitigation. As a result, severe areas in daytime have high SVF rate, sensible heat is generated. Day comfort areas have shadow effect

Quebec residential electricity demand: a microeconometric approach

International Nuclear Information System (INIS)

Bernard, J.T.; Bolduc, D.; Belanger, D.

1996-01-01

An economic analysis of Quebec residential electricity demand was studied by micro-simulation models. These structural models describe all components which lead to decisions upon durable holdings and electric appliance usage. The demand for space and water heating systems was evaluated. Recent price change in favour of energy sources other than electricity were taken into account. Price and income elasticity ratios were found to be low, as expected when estimating short term use. The role played by socio-economic variables on the choice of space-water heating systems and electricity use was also examined. Recent conversions have indicated a trend toward preference by households in favour of natural gas or oil over electricity. 18 refs., 5 tabs., 1 fig

Demand response offered by households with direct electric heating

International Nuclear Information System (INIS)

Kofod, C.; Togeby, M.

2004-01-01

The peak power balance in the Nordic power system is gradually turning to be very tight, especially in the electric area of southern Sweden and eastern Denmark. Power stations are closed and hardly any investments in new production are carried out. Demand response is considered essential when the formation of spot prices shall send the signal of needed investments in new capacity. Demand response which are based on individual preferences, and carried out automatically, can be one way to increase the volume of price elastic demand. Demand response need hourly metering for calculation and documentation of the decrease in demand, and controllability in order to meet the timing requirements. Within the EU SAVE project EFFLOCOM (2002 - 2004), a Danish demand response pilot project was established in 2003 including 25 single family homes with direct electrical heating. The system has been tested during the winter 2003/2004. The tested technologies include hourly metering, communication by GRPS as well as the Internet. GPRS is used for daily remote meter reading and automatic control of the electric heating including individual control of up to five zones. The system is designed for automatic activation when the Nord Pool hourly Elspot prices exceed preset levels. The system can also be used as regulating power. The EFFLOCOM Web Bite includes an interactive demonstrator of the system. The developed customer Web Bite is including the services: 1) Access to setting the limits for the maximum duration of interruption for up to five different control zones for two periods of the day and for three price levels. 2) Access to stop an actual interruption. 3) A report on the hourly, daily, weekly and monthly use of electricity and the saved bonus by demand response control. The report is updated daily. The goals of up to 5 kW controlled per house were fulfilled. Besides the demand response bonus the customers have also saved electricity. A customer survey did show that the

The demands and resources arising from shared office spaces.

Science.gov (United States)

Morrison, Rachel L; Macky, Keith A

2017-04-01

The prevalence of flexible and shared office spaces is increasing significantly, yet the socioemotional outcomes associated with these environments are under researched. Utilising the job demands-resources (JD-R) model we investigate both the demands and the resources that can accrue to workers as a result of shared work environments and hot-desking. Data were collected from work experienced respondents (n = 1000) assessing the extent to which they shared their office space with others, along with demands comprising distractions, uncooperative behaviours, distrust, and negative relationships, and resources from co-worker friendships and supervisor support. We found that, as work environments became more shared (with hot-desking being at the extreme end of the continuum), not only were there increases in demands, but co-worker friendships were not improved and perceptions of supervisory support decreased. Findings are discussed in relation to employee well-being and recommendations are made regarding how best to ameliorate negative consequences of shared work environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Heating and cooling energy demand and related emissions of the German residential building stock under climate change

International Nuclear Information System (INIS)

Olonscheck, Mady; Holsten, Anne; Kropp, Juergen P.

2011-01-01

The housing sector is a major consumer of energy. Studies on the future energy demand under climate change which also take into account future changes of the building stock, renovation measures and heating systems are still lacking. We provide the first analysis of the combined effect of these four influencing factors on the future energy demand for room conditioning of residential buildings and resulting greenhouse gas (GHG) emissions in Germany until 2060. We show that the heating energy demand will decrease substantially in the future. This shift will mainly depend on the number of renovated buildings and climate change scenarios and only slightly on demographic changes. The future cooling energy demand will remain low in the future unless the amount of air conditioners strongly increases. As a strong change in the German energy mix is not expected, the future GHG emissions caused by heating will mainly depend on the energy demand for future heating. - Highlights: → The future heating energy demand of German residential buildings strongly decreases. → Extent of these changes mainly depends on the number of renovated buildings. → Demographic changes will only play a minor role. → Cooling energy demand will remain low in future but with large insecurities. → Germany's 2050 emission targets for the building stock are ambitious.

Demands for Space Transportation Systems for the next 30 years

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Demands for Space Transportation Systems for the next 30 years. Meeting the in-house and commercial launch demand for Communication and Remote Sensing spacecraft. Payload capability enhancement for expendable launch vehicles to meet the national needs.

NUMERICAL ANALYSIS OF HEAT STORAGE OF SOLAR HEAT IN FLOOR CONSTRUCTION

DEFF Research Database (Denmark)

Weitzmann, Peter; Holck, Ole; Svendsen, Svend

2003-01-01

with the highest energy con-sumption. The reduction depends on the solar collector area, distribution of the insulation thickness, heat-ing demand and control strategy, but not on pipe spacing and layer thickness and material. Finally, it is shown that the system can also be used for comfort heating of tiled...

A study of upwind schemes on the laminar hypersonic heating predictions for the reusable space vehicle

Science.gov (United States)

Qu, Feng; Sun, Di; Zuo, Guang

2018-06-01

With the rapid development of the Computational Fluid Dynamics (CFD), Accurate computing hypersonic heating is in a high demand for the design of the new generation reusable space vehicle to conduct deep space exploration. In the past years, most researchers try to solve this problem by concentrating on the choice of the upwind schemes or the definition of the cell Reynolds number. However, the cell Reynolds number dependencies and limiter dependencies of the upwind schemes, which are of great importance to their performances in hypersonic heating computations, are concerned by few people. In this paper, we conduct a systematic study on these properties respectively. Results in our test cases show that SLAU (Simple Low-dissipation AUSM-family) is with a much higher level of accuracy and robustness in hypersonic heating predictions. Also, it performs much better in terms of the limiter dependency and the cell Reynolds number dependency.

On variations of space-heating energy use in office buildings

International Nuclear Information System (INIS)

Lin, Hung-Wen; Hong, Tianzhen

2013-01-01

Highlights: • Space heating is the largest energy end use in the U.S. building sector. • A key design and operational parameters have the most influence on space heating. • Simulated results were benchmarked against actual results to analyze discrepancies. • Yearly weather changes have significant impact on space heating energy use. • Findings enable stakeholders to make better decisions on energy efficiency. - Abstract: Space heating is the largest energy end use, consuming more than seven quintillion joules of site energy annually in the U.S. building sector. A few recent studies showed discrepancies in simulated space-heating energy use among different building energy modeling programs, and the simulated results are suspected to be underpredicting reality. While various uncertainties are associated with building simulations, especially when simulations are performed by different modelers using different simulation programs for buildings with different configurations, it is crucial to identify and evaluate key driving factors to space-heating energy use in order to support the design and operation of low-energy buildings. In this study, 10 design and operation parameters for space-heating systems of two prototypical office buildings in each of three U.S. heating climates are identified and evaluated, using building simulations with EnergyPlus, to determine the most influential parameters and their impacts on variations of space-heating energy use. The influence of annual weather change on space-heating energy is also investigated using 30-year actual weather data. The simulated space-heating energy use is further benchmarked against those from similar actual office buildings in two U.S. commercial-building databases to better understand the discrepancies between simulated and actual energy use. In summary, variations of both the simulated and actual space-heating energy use of office buildings in all three heating climates can be very large. However

Pseudo dynamic transitional modeling of building heating energy demand using artificial neural network

NARCIS (Netherlands)

Paudel, S.; Elmtiri, M.; Kling, W.L.; Corre, le O.; Lacarriere, B.

2014-01-01

This paper presents the building heating demand prediction model with occupancy profile and operational heating power level characteristics in short time horizon (a couple of days) using artificial neural network. In addition, novel pseudo dynamic transitional model is introduced, which consider

Evolution of residential electricity demand by end-use in Quebec 1979-1989: A conditional demand analysis

International Nuclear Information System (INIS)

Lafrance, G.; Perron, D.

1994-01-01

Some of the main conclusions are presented from a temporal analysis of three large-scale electricity demand surveys (1979, 1984, and 1989) for the Quebec residential sector. A regression method called conditional demand analysis was used. The study allows a number of conclusions about certain electricity consumption trends by end-uses from 1979 to 1989 by household type and by vintage category. For example, the results indicate that decreasing electricity consumption between 1979 and 1984 for a typical dwelling equipped with electric space heating was mainly related to a large decline in net heating consumption. Overall, the results suggest that some permanent energy savings have been realized by a typical household equipped with an electric heating system due to improvements in standards and changes in customer behavior. These energy savings were partly offset by increased electricity consumption from the purchase of new appliances and an increase in the demand for hot water. 7 refs., 1 fig., 8 tabs

Modeling global residential sector energy demand for heating and air conditioning in the context of climate change

International Nuclear Information System (INIS)

Isaac, Morna; Vuuren, Detlef P. van

2009-01-01

In this article, we assess the potential development of energy use for future residential heating and air conditioning in the context of climate change. In a reference scenario, global energy demand for heating is projected to increase until 2030 and then stabilize. In contrast, energy demand for air conditioning is projected to increase rapidly over the whole 2000-2100 period, mostly driven by income growth. The associated CO 2 emissions for both heating and cooling increase from 0.8 Gt C in 2000 to 2.2 Gt C in 2100, i.e. about 12% of total CO 2 emissions from energy use (the strongest increase occurs in Asia). The net effect of climate change on global energy use and emissions is relatively small as decreases in heating are compensated for by increases in cooling. However, impacts on heating and cooling individually are considerable in this scenario, with heating energy demand decreased by 34% worldwide by 2100 as a result of climate change, and air-conditioning energy demand increased by 72%. At the regional scale considerable impacts can be seen, particularly in South Asia, where energy demand for residential air conditioning could increase by around 50% due to climate change, compared with the situation without climate change

Residential solar-heating system

Science.gov (United States)

1978-01-01

Complete residential solar-heating and hot-water system, when installed in highly-insulated energy-saver home, can supply large percentage of total energy demand for space heating and domestic hot water. System which uses water-heating energy storage can be scaled to meet requirements of building in which it is installed.

The annual number of days that solar heated water satisfies a specified demand temperature

Energy Technology Data Exchange (ETDEWEB)

Yohanis, Y.G. [Thermal Systems Engineering Group, Faculty of Engineering, University of Ulster, BT37 0QB Northern Ireland (United Kingdom); Popel, O.; Frid, S.E. [Non-traditional Renewable Energy Sources, Institute for High Temperatures, Russian Academy of Sciences, 13/19 Izhorskaya str., IVTAN, Moscow 127412 (Russian Federation); Norton, B. [Dublin Institute of Technology, Aungier Street, Dublin 2 (Ireland)

2006-08-15

An analysis of solar water heating systems determines the number of days in each month when solar heated water wholly meets demand above a set temperature. The approach has been used to investigate the potential contribution to water heating loads of solar water heating in two UK locations. Correlations between the approach developed and the use of solar fractions are discussed. (author)

Anthropogenic heat flux estimation from space

NARCIS (Netherlands)

Chrysoulakis, Nektarios; Marconcini, Mattia; Gastellu-Etchegorry, Jean Philippe; Grimmond, C.S.B.; Feigenwinter, Christian; Lindberg, Fredrik; Frate, Del Fabio; Klostermann, Judith; Mitraka, Zina; Esch, Thomas; Landier, Lucas; Gabey, Andy; Parlow, Eberhard; Olofson, Frans

2016-01-01

H2020-Space project URBANFLUXES (URBan ANthrpogenic heat FLUX from Earth observation Satellites) investigates the potential of Copernicus Sentinels to retrieve anthropogenic heat flux, as a key component of the Urban Energy Budget (UEB). URBANFLUXES advances the current knowledge of the impacts

ANthropogenic heat FLUX estimation from Space

NARCIS (Netherlands)

Chrysoulakis, Nektarios; Marconcini, Mattia; Gastellu-Etchegorry, Jean Philippe; Grimmong, C.S.B.; Feigenwinter, Christian; Lindberg, Fredrik; Frate, Del Fabio; Klostermann, Judith; Mi, Zina; Esch, Thomas; Landier, Lucas; Gabey, Andy; Parlow, Eberhard; Olofson, Frans

2017-01-01

The H2020-Space project URBANFLUXES (URBan ANthrpogenic heat FLUX from Earth observation Satellites) investigates the potential of Copernicus Sentinels to retrieve anthropogenic heat flux, as a key component of the Urban Energy Budget (UEB). URBANFLUXES advances the current knowledge of the

Modelling the impact of urban form on household energy demand and related CO2 emissions in the Greater Dublin Region

International Nuclear Information System (INIS)

Liu Xiaochen; Sweeney, John

2012-01-01

This study aims to investigate the relationship between household space heating energy use and urban form (land use characteristics) for the Greater Dublin Region. The geographical distributions of household energy use are evaluated at the Enumeration Districts (ED) level based on the building thermal balance model. Moreover, it estimates the impact of possible factors on the household space heating consumption. Results illustrate that the distribution profile of dwellings is a significant factor related to overall heating energy demand and individual dwelling energy consumption for space heating. Residents living in compact dwellings with small floor areas consume less energy for space heating than residents living in dwellings with big floor areas. Moreover, domestic heating energy demand per household was also estimated for two extreme urban development scenarios: the compact city scenario and the dispersed scenario. The results illustrate that the compact city scenario is likely to decrease the domestic heating energy consumption per household by 16.2% compared with the dispersed city scenario. Correspondingly, the energy-related CO 2 emissions could be significantly decreased by compact city scenario compared with the dispersed city scenario. - Highlights: ► A method was developed to investigate urban form impacts on energy demand. ► This study estimates impacts of possible factors on the household energy consumption. ► Household heating energy demand is sensitive to dwelling distribution profile. ► The compact case could reduce domestic energy demand compared with the dispersed case.

Crawl space assisted heat pump. [using stored ground heat

Science.gov (United States)

Ternes, M. P.

1980-01-01

A variety of experiments and simulations, currently being designed or underway, to determine the feasibility of conditioning the source air of an air to air heat pump using stored ground heat or cool to produce higher seasonal COP's and net energy savings are discussed. The ground would condition ambient air as it is drawn through the crawl space of a house. Tests designed to evaluate the feasibility of the concept, to determine the amount of heat or cool available from the ground, to study the effect of the system on the heating and cooling loads of the house, to study possible mechanisms which could enhance heat flow through the ground, and to determine if diurnal temperature swings are necessary to achieve successful system performance are described.

Integration of Space Heating and Hot Water Supply in Low Temperature District Heating

DEFF Research Database (Denmark)

Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael

2014-01-01

pipes, where the water is at the highest temperature. The heat loss may be lowered by decreasing the temperatures in the network for which reason low temperature networks are proposed as a low loss solution for future district heating. However, the heating demand of the consumers involve both domestic......District heating makes it possible to provide heat for many consumers in an efficient manner. In particular, district heating based on combined heat and power production is highly efficient. One disadvantage of district heating is that there is a significant heat loss from the pipes...... to the surrounding ground. In larger networks involving both transmission and distribution systems, the heat loss is most significant from the distribution network. An estimate is that about 80-90 % of the heat loss occurs in the distribution system. In addition, the heat loss is naturally highest from the forward...

Design of stationary PEFC system configurations to meet heat and power demands

Science.gov (United States)

Wallmark, Cecilia; Alvfors, Per

This paper presents heat and power efficiencies of a modeled PEFC system and the methods used to create the system configuration. The paper also includes an example of a simulated fuel cell system supplying a building in Sweden with heat and power. The main method used to create an applicable fuel cell system configuration is pinch technology. This technology is used to evaluate and design a heat exchanger network for a PEFC system working under stationary conditions, in order to find a solution with high heat utilization. The heat exchanger network in the system connecting the reformer, the burner, gas cleaning, hot-water storage and the PEFC stack will affect the heat transferred to the hot-water storage and thereby the heating of the building. The fuel, natural gas, is reformed to a hydrogen-rich gas within a slightly pressurized system. The fuel processor investigated is steam reforming, followed by high- and low-temperature shift reactors and preferential oxidation. The system is connected to the electrical grid for backup and peak demands and to a hot-water storage to meet the varying heat demand for the building. The procedure for designing the fuel cell system installation as co-generation system is described, and the system is simulated for a specific building in Sweden during 1 year. The results show that the fuel cell system in combination with a burner and hot-water storage could supply the building with the required heat without exceeding any of the given limitations. The designed co-generation system will provide the building with most of its power requirements and would further generate income by sale of electricity to the power grid.

The sizes of Flat Plate and Evacuated Tube Collectors with Heat Pipe area as a function of the share of solar system in the heat demand

Directory of Open Access Journals (Sweden)

Olek Małgorzata

2016-01-01

Full Text Available The popularity of solar collectors in Poland is still increasing. The correct location of the collectors and a relatively high density of solar radiation allow delivering heat even in spite of relatively low ambient temperature. Moreover, solar systems used for heating domestic heat water (DHW in summer allow nearly complete elimination of conventional energy sources (e.g. gas, coal. That is why more and more house owners in Poland decide to install solar system installations. In Poland the most common types of solar collectors are flat plate collectors (FPC and evacuated tube collectors with heat pipe (ETCHP; both were selected for the analysis. The heat demand related to the preparation of hot water, connected with the size of solar collectors’ area, has been determined. The analysis includes FPC and ETCHP and heat demand of less than 10 000 kWh/year. Simulations were performed with the Matlab software and using data from a typical meteorological year (TMY. In addition, a 126–year period of measurements of insolation for Krakow has been taken into account. The HDKR model (Hay, Davis, Klucher, Reindl was used for the calculation of solar radiation on the absorber surface. The monthly medium temperature of the absorber depends on the amount of solar system heat and on the heat demand. All the previously mentioned data were used to determine solar efficiency. Due to the fact that solar efficiency and solar system heat are connected, the calculations were made with the use of an iterative method. Additionally, the upper limit for monthly useful solar system heat is resulted from the heat demand and thus the authors prepared a model of statistical solar system heat deviations based on the Monte Carlo method. It has been found that an increase in the useful solar system heat in reference to the heat demand is associated with more than proportional increase in the sizes of the analyzed surfaces of solar collector types.

Thulium heat sources for space power applications

International Nuclear Information System (INIS)

Alderman, C.J.

1992-05-01

Reliable power supplies for use in transportation and remote systems will be an important part of space exploration terrestrial activities. A potential power source is available in the rare earth metal, thulium. Fuel sources can be produced by activating Tm-169 targets in the space station reactor. The resulting Tm-170 heat sources can be used in thermoelectric generators to power instrumentation and telecommunications located at remote sites such as weather stations. As the heat source in a dynamic Sterling or Brayton cycle system, the heat source can provide a lightweight power source for rovers or other terrestrial transportation systems

Projecting demand and supply of forest biomass for heating in Norway

International Nuclear Information System (INIS)

Tromborg, Erik; Havskjold, Monica; Lislebo, Ole; Rorstad, Per Kristian

2011-01-01

This paper assesses the increase in demand and supply for forest biomass for heating in Norway in 2020. By then there is a political aim to double the national production of bioenergy from the level in 2008. The competitiveness of woody biomass in central and district heating is analyzed in a model selecting the least-cost heating technology and scale in municipalities given a set of constraints and under different fuels price scenarios. The supply of forest biomass from roundwood is estimated based on data of forest inventories combined with elasticities regarding price and standing volumes. The supply of biomass from harvesting residues is estimated in an engineering approach based on data from the national forest inventories and roundwood harvest. The results show how the production of bioenergy is affected by changes in energy prices and support schemes for bioenergy. One conclusion from the analyses is that the government target of 14 TWh more bioenergy by 2020 is not likely to be met by current technologies and policy incentives. The contribution of the analysis is the detailed presentation of the heat market potentials and technology choices combined with supply functions for both roundwood and harvesting residues. - Highlights: → This paper accesses the demand and supply for forest biomass for heating in Norway in 2020. → Market share for wood in central and new district heating is analyzed in a cost-minimizing model. → The supply of forest biomass includes wood chips from import, roundwood and harvesting residues. → The production of bioenergy is affected by changes in energy prices and support schemes. → The government target for bioenergy is not met by current technologies and policy incentives.

Potential for solar space heating in Scotland

Energy Technology Data Exchange (ETDEWEB)

Macgregor, A W.K.

1980-07-01

This paper investigates the relative effectiveness of passive-type solar-assisted space heating systems at various latitudes within the British Isles. A comparison is made of the useful solar gain of the same system linked to the same house at four different locations. Month-by-month energy balances indicate that the annual useful solar contribution at the highest latitude (Lerwick, 60 deg N) is about 35% higher than at the lowest latitude (Kew, 53 deg N). The main reason for this difference is the higher heating loads in the north, particularly outside the winter months. The estimated available irradiation on south-facing vertical surfaces was almost the same at all four locations. Previous work in the UK indicates that, contrary to the conclusions in this paper, more southerly latitudes were the most favorable for solar space heating. The reasons for the disparity are discussed. It is recommended that research and development of passive solar-assisted space heating systems should be most vigorously pursued in the more northerly latitudes of the British Isles, where both the potential benefit and the need are greatest.

Solar thermal space heating combined with swimming pool heating: A promising solution for southern Europe climates

Energy Technology Data Exchange (ETDEWEB)

Carvalho, M.J.; Neves, Ana [INETI/DER, Lisboa (Portugal)

2006-07-01

The system concept evaluation performed focused on systems that can provide hot water, space heating and swimming-pool heating, and are designed for application in southern climates specifically for single-family houses. Due to the climate characteristics of southern Europe, space heating is required only for a few months in the year. In this evaluation it was considered a six month period for space heating and, on the other six months, swimming pool heating was considered. This type of systems are applicable to a niche market of people who are building their houses as single-family houses and want also to take profit of the good climate conditions for the use of solar energy. It is common that the construction of a swimming pool is also planned and constructed. The evaluation is made considering as reference system a factory made with 4m{sup 2} collector area and 300 l storage tank. The system in evaluation offers extra service - space heating and swimming pool heating and is formed by a collector field and a combistore providing solar hot water preparation and space heating in the winter period and providing also swimming pool heating in the summer period. The evaluation made shows that in southern Europe climates this system will give extra service in comparison to the traditional solar systems used and can be economically interesting.

Effects of atmospheric variability on energy utilization and conservation. [Space heating energy demand modeling; Program HEATLOAD

Energy Technology Data Exchange (ETDEWEB)

Reiter, E.R.; Johnson, G.R.; Somervell, W.L. Jr.; Sparling, E.W.; Dreiseitly, E.; Macdonald, B.C.; McGuirk, J.P.; Starr, A.M.

1976-11-01

Research conducted between 1 July 1975 and 31 October 1976 is reported. A ''physical-adaptive'' model of the space-conditioning demand for energy and its response to changes in weather regimes was developed. This model includes parameters pertaining to engineering factors of building construction, to weather-related factors, and to socio-economic factors. Preliminary testing of several components of the model on the city of Greeley, Colorado, yielded most encouraging results. Other components, especially those pertaining to socio-economic factors, are still under development. Expansion of model applications to different types of structures and larger regions is presently underway. A CRT-display model for energy demand within the conterminous United States also has passed preliminary tests. A major effort was expended to obtain disaggregated data on energy use from utility companies throughout the United States. The study of atmospheric variability revealed that the 22- to 26-day vacillation in the potential and kinetic energy modes of the Northern Hemisphere is related to the behavior of the planetary long-waves, and that the midwinter dip in zonal available potential energy is reflected in the development of blocking highs. Attempts to classify weather patterns over the eastern and central United States have proceeded satisfactorily to the point where testing of our method for longer time periods appears desirable.

Secular trends in monthly heating and cooling demands in Croatia

Science.gov (United States)

Cvitan, Lidija; Sokol Jurković, Renata

2016-08-01

This paper analyzes long-term heating and cooling trends for five locations in Croatia from 1901 to 2008 to assist in the revision of Croatia's heating and cooling energy policy. Trends in monthly heating degree-days (HDD) and cooling degree-days (CDD) were determined for three related temperature threshold values each and analyzed to provide insight into the influence of desired thermal comfort on the extent of changes in energy consumption. Monthly trends in the corresponding number of heating days (HD) and cooling days (CD) were also analyzed. A basic investigation of HDD, HD, CDD, and CD trends proved to be essential to the development of a complete description of important climate-related conditions that impact energy demands associated with heating and cooling. In a few cases, the dependence of the trends on the implemented temperature thresholds was rather pronounced and was reflected in great spatial and temporal variations in monthly trends. The statistical significance of the detected monthly trends illustrated a diverse range of possible impacts of climate changes on heating and cooling energy consumption both across and within three main climate regions in Croatia (continental, mountainous, and maritime). It is confirmed that the applied monthly scale for analyses is suitable for assessing heating and cooling practices.

Solar Energy for Space Heating & Hot Water.

Science.gov (United States)

Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

This pamphlet reviews the direct transfer of solar energy into heat, particularly for the purpose of providing space and hot water heating needs. Owners of buildings and homes are provided with a basic understanding of solar heating and hot water systems: what they are, how they perform, the energy savings possible, and the cost factors involved.…

BIODIESEL BLENDS IN SPACE HEATING EQUIPMENT

International Nuclear Information System (INIS)

KRISHNA, C.R.

2001-01-01

Biodiesel is a diesel-like fuel that is derived from processing vegetable oils from various sources, such as soy oil, rapeseed or canola oil, and also waste vegetable oils resulting from cooking use. Brookhaven National laboratory initiated an evaluation of the performance of blends of biodiesel and home heating oil in space heating applications under the sponsorship of the Department of Energy (DOE) through the National Renewable Energy Laboratory (NREL). This report is a result of this work performed in the laboratory. A number of blends of varying amounts of a biodiesel in home heating fuel were tested in both a residential heating system and a commercial size boiler. The results demonstrate that blends of biodiesel and heating oil can be used with few or no modifications to the equipment or operating practices in space heating. The results also showed that there were environmental benefits from the biodiesel addition in terms of reductions in smoke and in Nitrogen Oxides (NOx). The latter result was particularly surprising and of course welcome, in view of the previous results in diesel engines where no changes had been seen. Residential size combustion equipment is presently not subject to NOx regulation. If reductions in NOx similar to those observed here hold up in larger size (commercial and industrial) boilers, a significant increase in the use of biodiesel-like fuel blends could become possible

Experimental validation of the buildings energy performance (PEC assessment methods with reference to occupied spaces heating

Directory of Open Access Journals (Sweden)

Cristian PETCU

2010-01-01

Full Text Available This paper is part of the series of pre-standardization research aimed to analyze the existing methods of calculating the Buildings Energy Performance (PEC in view of their correction of completing. The entire research activity aims to experimentally validate the PEC Calculation Algorithm as well as the comparative application, on the support of several case studies focused on representative buildings of the stock of buildings in Romania, of the PEC calculation methodology for buildings equipped with occupied spaces heating systems. The targets of the report are the experimental testing of the calculation models so far known (NP 048-2000, Mc 001-2006, SR EN 13790:2009, on the support provided by the CE INCERC Bucharest experimental building, together with the complex calculation algorithms specific to the dynamic modeling, for the evaluation of the occupied spaces heat demand in the cold season, specific to the traditional buildings and to modern buildings equipped with solar radiation passive systems, of the ventilated solar space type. The schedule of the measurements performed in the 2008-2009 cold season is presented as well as the primary processing of the measured data and the experimental validation of the heat demand monthly calculation methods, on the support of CE INCERC Bucharest. The calculation error per heating season (153 days of measurements between the measured heat demand and the calculated one was of 0.61%, an exceptional value confirming the phenomenological nature of the INCERC method, NP 048-2006. The mathematical model specific to the hourly thermal balance is recurrent – decisional with alternating paces. The experimental validation of the theoretical model is based on the measurements performed on the CE INCERC Bucharest building, within a time lag of 57 days (06.01-04.03.2009. The measurements performed on the CE INCERC Bucharest building confirm the accuracy of the hourly calculation model by comparison to the values

Meeting Czechoslovak demands for heat in long-term prospective, especially with regard to nuclear sources

International Nuclear Information System (INIS)

Klail, M.

1988-01-01

The development was studied of heat demand in the CSSR till the year 2030. The ratio of centralized and decentralized heat supply is currently 60 to 40; in the future a slight increase is expected in the decentralized type of heat supply, mainly as a result of more intensive use of natural gas. In 2030, 710 PU of centralized heat should be produced. A decisive element in meeting the demand will be a growing proportion of combined production of electric power and heat by nuclear power plants. The installed capacity of the nuclear power plants in 2030 should range between 23 and 41 thousand MW, the production of electric power in these plants should be 193 to 238 TWh/y. 109 territorial areas potentially suitable for use of heat from nuclear sources were selected. They were included in 19 regions of which 9 should in the year 2010 be linked to heat supply from nuclear power plants that will be in operation. It is expected that in the year 2030, nuclear sources will supply 250 PU of centralized heat. (Z.M.). 2 tabs., 14 refs

Modelling of air-conditioned and heated spaces

Energy Technology Data Exchange (ETDEWEB)

Moehl, U

1987-01-01

A space represents a complex system involving numerous components, manipulated variables and disturbances which need to be described if dynamic behaviour of space air is to be determined. A justifiable amount of simulation input is determined by the application of adjusted modelling of the individual components. The determination of natural air exchange in heated spaces and of space-air flow in air-conditioned space are a primary source of uncertainties. (orig.).

Eliminating LH2 in LOX-collect space launchers - Key to on-demand capability

Science.gov (United States)

Leingang, J. L.; Carreiro, L. R.; Maurice, L. Q.

1993-01-01

Two air-breathing reusable two-stage space launch vehicle concepts are proposed, in which the first stage employs turboramjet propulsion and the second stage uses rockets, which are expected to provide very rapid response launch of 10,000 lb polar-orbit payloads. In both concepts, liquid oxygen (LOX) for the second stage is collected during first stage ascent, thus eliminating the need for LOX ground servicing facilities. In the first concept, liquid hydrogen in the amount just sufficient to condense and collect second state LOX is the only cryogenic fluid that is loaded on the vehicle at takeoff. The second concept uses the heat sink of conventional jet propulsion fuel and water coolant to drive a lightweight adaptation of the commercial LOX production process, eliminating all cryogenics at takeoff. Both concepts should permit true launch-on-demand capability with aircraftlike ground operations.

Impact on energy requirements and emissions of heat pumps and micro-cogenerators participating in demand side management

International Nuclear Information System (INIS)

Cooper, Samuel J.G.; Hammond, Geoffrey P.; McManus, Marcelle C.; Rogers, John G.

2014-01-01

The potential impacts of participating in demand side management (DSM) on the performance of air source heat pumps (ASHP) and micro-combined heat and power (mCHP) units are considered by this study. As significant consumers and generators of electricity at the distribution level, large numbers of heat pumps and micro-cogenerators would provide considerable scope for participation in DSM systems. However, it is possible that operating regimes which are optimised for grid considerations will not achieve the maximum performance that is possible from the units. Modelling has been conducted to investigate the significance of this effect, considering the case where local distribution constraints are the main driver for demand side interventions. A model of domestic electrical demand has been adapted to consider a neighbourhood of 128 dwellings in order to identify when interventions are necessary. This has been combined with dynamic models of two combustion engine micro-cogenerators, a solid oxide fuel cell micro-cogenerator and two ASHPs. A simple thermal model of each building is combined with a range of user preferences in order to determine the preferred operating profiles of the heating units. The DSM scheme analysed here is likely to have minimal impact on the emissions and energy requirements associated with each heating unit. Its effect is similar to that which occurs without DSM if the control system gain is relaxed such that equivalent thermal comfort is achieved. DSM can reduce the peak electrical demand of the neighbourhood. However, in the scenarios investigated, it is unlikely that the peaks can be reduced sufficiently such that they do not exceed the capacity of the local distribution transformer if ASHPs are used in all dwellings. By using a combination of mCHP units with ASHPs, it is possible to supply heating to all dwellings without exceeding this capacity. In this case, the use of DSM can increase the ratio of ASHPs used. In the context of a low

Potential for increased wind-generated electricity utilization using heat pumps in urban areas

International Nuclear Information System (INIS)

Waite, Michael; Modi, Vijay

2014-01-01

Highlights: • Large-scale wind power and increased electric heat pumps were evaluated. • A deterministic model of wind power and electricity demand was developed. • Sub-models for space heating and domestic hot water demand were developed. • Increased use of heat pumps can improve the viability of large-scale wind power. • Larger wind power capacity can meet a target utilization rate with more heat pumps. - Abstract: The U.S. has substantial wind power potential, but given wind’s intermittent availability and misalignment with electricity demand profiles, large-scale deployment of wind turbines could result in high electricity costs due to energy storage requirements or low utilization rates. While fuel switching and heat pumps have been proposed as greenhouse gas (GHG) emissions and energy reduction strategies at the building scale, this paper shows that heat pump adoption could have additional system-wide benefits by increasing the utilization of wind-generated electricity. A model was developed to evaluate the effects of coupling large-scale wind power installations in New York State with increased use of electric heat pumps to meet a portion of space heating and domestic hot water (DHW) demands in New York City. The analysis showed significant increases in wind-generated electricity utilization with increased use of heat pumps, allowing for higher installed capacity of wind power. One scenario indicates that 78.5% annual wind-generated electricity utilization can be achieved with 3 GW of installed wind power capacity generated electricity equal to 20% of existing NYC annual electricity demand; if 20% of space heating and DHW demands are provided by heat pumps, the 78.5% utilization rate can be achieved with an increase of total wind power capacity to 5 GW. Therefore, this integrated supply–demand approach could provide additional system-wide emissions reductions

Profiling Space Heating Behavior in Chilean Social Housing: Towards Personalization of Energy Efficiency Measures

Directory of Open Access Journals (Sweden)

Victor Bunster

2015-06-01

Full Text Available Global increases in the demand for energy are imposing strong pressures over the environment while compromising the capacity of emerging economies to achieve sustainable development. In this context, implementation of effective strategies to reduce consumption in residential buildings has become a priority concern for policy makers as minor changes at the household scale can result in major energy savings. This study aims to contribute to ongoing research on energy consumer profiling by exploring the forecasting capabilities of discrete socio-economic factors that are accessible through social housing allocation systems. Accordingly, survey data gathered by the Chilean Ministry of Social Development was used identify key characteristics that may predict firewood usage for space heating purposes among potential beneficiaries of the Chilean social housing program. The analyzed data evidences strong correlations between general household characteristics and space heating behavior in certain climatic zones, suggesting that personalized delivery of energy efficiency measures can potentially increase the effectiveness of initiatives aimed towards the reduction of current patterns of consumption.

Theoretical energy and exergy analyses of solar assisted heat pump space heating system

Directory of Open Access Journals (Sweden)

Atmaca Ibrahim

2014-01-01

Full Text Available Due to use of alternative energy sources and energy efficient operation, heat pumps come into prominence in recent years. Especially in solar-assisted heat pumps, sizing the required system is difficult and arduous task in order to provide optimum working conditions. Therefore, in this study solar assisted indirect expanded heat pump space heating system is simulated and the results of the simulation are compared with available experimental data in the literature in order to present reliability of the model. Solar radiation values in the selected region are estimated with the simulation. The case study is applied and simulation results are given for Antalya, Turkey. Collector type and storage tank capacity effects on the consumed power of the compressor, COP of the heat pump and the overall system are estimated with the simulation, depending on the radiation data, collector surface area and the heating capacity of the space. Exergy analysis is also performed with the simulation and irreversibility, improvement potentials and exergy efficiencies of the heat pump and system components are estimated.

Green hypocrisy? Environmental attitudes and residential space heating expenditure

OpenAIRE

Traynor, Laura; Lange, Ian A.; Moro, Mirko

2012-01-01

In the UK, the largest proportion of household energy use is for space heating. Popular media make claims of a green hypocrisy: groups which have the strongest attitude towards the environment have the highest emissions. This study examines whether environmental attitudes and behaviours are associated with space heating energy use using data from the British Household Panel Survey. Results find that environmentally friendly attitudes generally do not lead to lower heating expenditures though ...

Hybrid Heat Pipes for Lunar and Martian Surface and High Heat Flux Space Applications

Science.gov (United States)

Ababneh, Mohammed T.; Tarau, Calin; Anderson, William G.; Farmer, Jeffery T.; Alvarez-Hernandez, Angel R.

2016-01-01

Novel hybrid wick heat pipes are developed to operate against gravity on planetary surfaces, operate in space carrying power over long distances and act as thermosyphons on the planetary surface for Lunar and Martian landers and rovers. These hybrid heat pipes will be capable of operating at the higher heat flux requirements expected in NASA's future spacecraft and on the next generation of polar rovers and equatorial landers. In addition, the sintered evaporator wicks mitigate the start-up problems in vertical gravity aided heat pipes because of large number of nucleation sites in wicks which will allow easy boiling initiation. ACT, NASA Marshall Space Flight Center, and NASA Johnson Space Center, are working together on the Advanced Passive Thermal experiment (APTx) to test and validate the operation of a hybrid wick VCHP with warm reservoir and HiK"TM" plates in microgravity environment on the ISS.

Adaptive heat pump and battery storage demand side energy management

Science.gov (United States)

Sobieczky, Florian; Lettner, Christian; Natschläger, Thomas; Traxler, Patrick

2017-11-01

An adaptive linear model predictive control strategy is introduced for the problem of demand side energy management, involving a photovoltaic device, a battery, and a heat pump. Moreover, the heating influence of solar radiation via the glass house effect is considered. Global sunlight radiation intensity and the outside temperature are updated by weather forecast data. The identification is carried out after adapting to a time frame witch sufficiently homogeneous weather. In this way, in spite of the linearity an increase in precision and cost reduction of up to 46% is achieved. It is validated for an open and closed loop version of the MPC problem using real data of the ambient temperature and the global radiation.

Heating of roads. Heat consumption and heat output as a function of climate, construction, demands on surface conditions and principle of heat supply. Uppvaermning av vaegar

Energy Technology Data Exchange (ETDEWEB)

Magnusson, R

1977-01-01

In this work analytical formulas for calculation of temperatures in a heated roadbed are given. The heat flux from a heated surface has been studied. The methods for snowclearence on different types of roads have been investigated. The construction work has been studied. The analytical formulas have been evaluated by comparison between calculated temperatures and temperatures measured in field and laboratory. The heat transfer coefficients in those formulas have been developed empirically by tests in laboratory and field. Surfaces with different types of traffic are divided into three classes according to the demands for snow removal. The construction work has been divided into cost elements. This has given a basis for calculating the economic effects of alternative designs. By this work has been developed a method useful on one hand for calculation of the optimum principle of regulation of the supply of heat and on the other hand for the design of the heat installations in the road.

Post-evaluation of a ground source heat pump system for residential space heating in Shanghai China

Science.gov (United States)

Lei, Y.; Tan, H. W.; Wang, L. Z.

2017-11-01

Residents of Southern China are increasingly concerned about the space heating in winter. The chief aim of the present work is to find a cost-effective way for residential space heating in Shanghai, one of the biggest city in south China. Economic and energy efficiency of three residential space heating ways, including ground source heat pump (GSHP), air source heat pump (ASHP) and wall-hung gas boiler (WHGB), are assessed based on Long-term measured data. The results show that the heat consumption of the building is 120 kWh/m2/y during the heating season, and the seasonal energy efficiency ratio (SEER) of the GSHP, ASHP and WHGB systems are 3.27, 2.30, 0.88 respectively. Compared to ASHP and WHGB, energy savings of GSHP during the heating season are 6.2 kgce/(m2.y) and 2.2 kgce/(m2.y), and the payback period of GSHP are 13.3 and 7.6 years respectively. The sensitivity analysis of various factors that affect the payback period is carried out, and the results suggest that SEER is the most critical factor affecting the feasibility of ground source heat pump application, followed by building load factor and energy price factor. These findings of the research have led the author to the conclusion that ground source heat pump for residential space heating in Shanghai is a good alternative, which can achieve significant energy saving benefits, and a good system design and operation management are key factors that can shorten the payback period.

Green hypocrisy? Environmental attitudes and residential space heating expenditure

Energy Technology Data Exchange (ETDEWEB)

Traynor, Laura; Lange, Ian; Moro, Mirko [Stirling Univ. (United Kingdom). Division of Economics

2012-06-15

In the UK, the largest proportion of household energy use is for space heating. Popular media make claims of a green hypocrisy: groups which have the strongest attitude towards the environment have the highest emissions. This study examines whether environmental attitudes and behaviours are associated with space heating energy use using data from the British Household Panel Survey. Results find that environmentally friendly attitudes generally do not lead to lower heating expenditures though environmentally friendly behaviours are associated with lower heating expenditure. Also, the effect of these attitudes and behaviours do not change as income increase.

Demand side management in South Africa at industrial residence water heating systems using in line water heating methodology

International Nuclear Information System (INIS)

Rankin, R.; Rousseau, P.G.

2008-01-01

The South African electrical utility, ESKOM, currently focuses its demand side management (DSM) initiatives on controlling electrical load between 18:00 and 20:00 each day, which is the utility's peak demand period. Funding is provided to energy service companies (ESCo's) to implement projects that can achieve load shifting out of this period. This paper describes how an improved in line water heating concept developed in previous studies was implemented into several real life industrial sanitary water heating systems to obtain the DSM load shift required by ESKOM. Measurements from a selection of these plants are provided to illustrate the significant load reductions that are being achieved during 18:00-20:00. The measured results also show that the peak load reduction is achieved without adversely affecting the availability of sufficient hot water to the persons using the showering and washing facilities served by the water heating system. A very good correlation also exists between these measured results and simulations that were done beforehand to predict the DSM potential of the project. The in line water heater concept provides an improved solution for DSM at sanitary water heating systems due to the stratified manner in which hot water is supplied to the tanks. This provides an improved hot water supply to users when compared to conventional in tank heating systems, even with load shifting being done. It also improves the storage efficiency of a plant, thereby allowing the available storage capacity of a plant to be utilized to its full extent for load shifting purposes

Validated TRNSYS Model for Solar Assisted Space Heating System

International Nuclear Information System (INIS)

Abdalla, Nedal

2014-01-01

The present study involves a validated TRNSYS model for solar assisted space heating system as applied to a residential building in Jordan using new detailed radiation models of the TRNSYS 17.1 and geometric building model Trnsys3d for the Google SketchUp 3D drawing program. The annual heating load for a building (Solar House) which is located at the Royal ScientiFIc Society (RS5) in Jordan is estimated under climatological conditions of Amman. The aim of this Paper is to compare measured thermal performance of the Solar House with that modeled using TRNSYS. The results showed that the annual measured space heating load for the building was 6,188 kWh while the heati.ng load for the modeled building was 6,391 kWh. Moreover, the measured solar fraction for the solar system was 50% while the modeled solar fraction was 55%. A comparison of modeled and measured data resulted in percentage mean absolute errors for solar energy for space heating, auxiliary heating and solar fraction of 13%, 7% and 10%, respectively. The validated model will be useful for long-term performance simulation under different weather and operating conditions.(author)

Heat and power demands in babassu palm oil extraction industry in Brazil

International Nuclear Information System (INIS)

Teixeira, Marcos A.

2005-01-01

The objective of this paper is to analyze the energy use profile of the babassu (Orbignya ssp-Palmae) oil extraction industry in Brazil in order to establish the basis for a cogeneration study of this important part of the Brazilian Northeast region economy, which is still ignored by energetic biomass studies. The work used information from new equipment suppliers that was analyzed against field information from operating units. The data was used to establish a basis for the thermal and mechanical energy consumption for the two main basic unit profiles for the sector: a simple one with just oil extraction and the other, more vertically integrated with other secondary by-products. For the energetic demand taken from the only oil extraction unit profile study, the minimum pressure for the steam process was estimated at 1.4MPa, electric demand at 5.79kW/ton of processed kernel and heat consumption at 2071MJ/ton of processed kernel (829kg steam/ton of processed kernel). For the vertically integrated unit profile, the following values were found: minimum pressure for the steam process 1.4MPa, electric demand 6.22kW/ton of processed kernel and heat consumption 21,503MJ/ton of processed kernel (7600kg steam/ton of processed kernel)

Low Temperature District Heating for Future Energy Systems

DEFF Research Database (Denmark)

Schmidt, Dietrich; Kallert, Anna; Blesl, Markus

2017-01-01

of the building stock. Low temperature district heating (LTDH) can contribute significantly to a more efficient use of energy resources as well as better integration of renewable energy (e.g. geothermal or solar heat), and surplus heat (e.g. industrial waste heat) into the heating sector. LTDH offers prospects......The building sector is responsible for more than one third of the final energy consumption of societies and produces the largest amount of greenhouse gas emissions of all sectors. This is due to the utilisation of combustion processes of mainly fossil fuels to satisfy the heating demand...... for both the demand side (community building structure) and the supply side (network properties or energy sources). Especially in connection with buildings that demand only low temperatures for space heating. The utilisation of lower temperatures reduces losses in pipelines and can increase the overall...

Utilization of Flexible Demand in a Virtual Power Plant Set-Up

DEFF Research Database (Denmark)

Thavlov, Anders; Bindner, Henrik W.

2014-01-01

High penetration levels from renewable energy sources in large-scale power systems demand a high degree of flexibility in the transmission and distribution system. This paper presents a method for utilization of flexible demand in the low-voltage distribution system using the thermal mass...... of a building to defer power consumption from electric space heating. The power consumption for heating is controlled by an operational virtual power plant, which is sending a set point for requested power consumption to the building management system. An optimization problem is formulated...

Climate Adaptivity and Field Test of the Space Heating Used Air-Source Transcritical CO2 Heat Pump

Science.gov (United States)

Song, Yulong; Ye, Zuliang; Cao, Feng

2017-08-01

In this study, an innovation of air-sourced transcritical CO2 heat pump which was employed in the space heating application was presented and discussed in order to solve the problem that the heating performances of the transcritical CO2 heat pump water heater deteriorated sharply with the augment in water feed temperature. An R134a cycle was adopted as a subcooling device in the proposed system. The prototype of the presented system was installed and supplied hot water for three places in northern China in winter. The field test results showed that the acceptable return water temperature can be increased up to 55°C, while the supply water temperature was raised rapidly by the presented prototype to up to 70°C directly, which was obviously appropriate to the various conditions of heating radiator in space heating application. Additionally, though the heating capacity and power dissipation decreased with the decline in ambient temperature or the augment in water temperature, the presented heat pump system performed efficiently whatever the climate and water feed temperature were. The real time COP of the presented system was generally more than 1.8 in the whole heating season, while the seasonal performance coefficient (SPC) was also appreciable, which signified that the economic efficiency of the presented system was more excellent than other space heating approaches such as fuel, gas, coal or electric boiler. As a result, the novel system will be a promising project to solve the energy issues in future space heating application.

The emissions from a space-heating biomass stove

International Nuclear Information System (INIS)

Koyuncu, T.; Pinar, Y.

2007-01-01

In this paper, the flue gas emissions of carbon monoxide (CO), nitrogen oxides (NO X ), sulphur dioxide (SO 2 ) and soot from an improved space-heating biomass stove and thermal efficiency of the stove have been investigated. Various biomass fuels such as firewood, wood shavings, hazelnut shell, walnut shell, peanut shell, seed shell of apricot (sweet and hot seed type), kernel removed corncob, wheat stalk litter (for cattle and sheep pen), cornhusk and maize stalk litter (for cattle pen) and charcoal were burned in the same space-heating biomass stove. Flue gas emissions were recorded during the combustion period at intervals of 5min. It was seen from the results that the flue gas emissions have different values depending on the characteristics of biomass fuels. Charcoal is the most appropriate biomass fuel for use in the space-heating biomass stoves because its combustion emits less smoke and the thermal efficiency of the stove is approximately 46%. (author)

Modelling energy demand in the buildings sector within the EU

Energy Technology Data Exchange (ETDEWEB)

O Broin, Eoin

2012-11-01

In the on-going effort within the EU to tackle greenhouse gas emissions and secure future energy supplies, the buildings sector is often referred to as offering a large potential for energy savings. The aim of this thesis is to produce scenarios that highlight the parameters that affect the energy demands and thus potentials for savings of the building sector. Top-down and bottom-up approaches to modelling energy demand in EU buildings are applied in this thesis. The top-down approach uses econometrics to establish the historical contribution of various parameters to energy demands for space and water heating in the residential sectors of four EU countries. The bottom-up approach models the explicit impact of trends in energy efficiency improvement on total energy demand in the EU buildings stock. The two approaches are implemented independently, i.e., the results from the top-down studies do not feed into those from the bottom-up studies or vice versa. The explanatory variables used in the top-down approach are: energy prices; heating degree days, as a proxy for outdoor climate; a linear time trend, as a proxy for technology development; and the lag of energy demand, as a proxy for inertia in the system. In this case, inertia refers to the time it takes to replace space and water heating systems in reaction to price changes. The analysis gives long-term price elasticities of demand as follows: for France, -0.17; for Italy, -0.35; for Sweden, -0.27; and for the UK, -0.35. These results reveal that the price elasticity of demand for space and water heating is inelastic in each of these cases. Nonetheless, scenarios created for the period up to 2050 using these elasticities and an annual price increase of 3 % show that demand can be reduced by more than 1 % per year in France and Sweden and by less than 1 % per year in Italy and the UK. In the bottom-up modelling, varying rates for conversion efficiencies, heating standards for new buildings, end-use efficiency, and

Domestic demand-side management (DSM): Role of heat pumps and thermal energy storage (TES) systems

International Nuclear Information System (INIS)

Arteconi, A.; Hewitt, N.J.; Polonara, F.

2013-01-01

Heat pumps are seen as a promising technology for load management in the built environment, in combination with the smart grid concept. They can be coupled with thermal energy storage (TES) systems to shift electrical loads from high-peak to off-peak hours, thus serving as a powerful tool in demand-side management (DSM). This paper analyzes heat pumps with radiators or underfloor heating distribution systems coupled with TES with a view to showing how a heat pump system behaves and how it influences the building occupants' thermal comfort under a DSM strategy designed to flatten the shape of the electricity load curve by switching off the heat pump during peak hours (16:00–19:00). The reference scenario for the analysis was Northern Ireland (UK). The results showed that the heat pump is a good tool for the purposes of DSM, also thanks to the use of TES systems, in particular with heating distribution systems that have a low thermal inertia, e.g. radiators. It proved possible to achieve a good control of the indoor temperature, even if the heat pump was turned off for 3 h, and to reduce the electricity bill if a “time of use” tariff structure was adopted. -- Highlights: ► Heat pump heating systems with thermal energy storage are considered. ► System behavior is investigated during a DSM strategy for reducing peak energy demand. ► Heat pump heating systems demonstrate to be able to have an active role in DSM programs. ► A TES system must be coupled with the heat pump in presence of low thermal inertia heating distribution systems. ► Central role played by incentives schemes to promote this technology

Experimental studies on a ground coupled heat pump with solar thermal collectors for space heating

International Nuclear Information System (INIS)

Xi, Chen; Hongxing, Yang; Lin, Lu; Jinggang, Wang; Wei, Liu

2011-01-01

This paper presents experimental studies on a solar-assisted ground coupled heat pump (SAGCHP) system for space heating. The system was installed at the Hebei Academy of Sciences in Shijiazhuang (lat. N38 o 03', long. E114 o 26'), China. Solar collectors are in series connection with the borehole array through plate heat exchangers. Four operation modes of the system were investigated throughout the coldest period in winter (Dec 5th to Dec 27th). The heat pump performance, borehole temperature distributions and solar colleting characteristics of the SAGCHP system are analyzed and compared when the system worked in continuous or intermittent modes with or without solar-assisted heating. The SAGCHP system is proved to perform space heating with high energy efficiency and satisfactory solar fraction, which is a promising substitute for the conventional heating systems. It is also recommended to use the collected solar thermal energy as an alternative source for the heat pump instead of recharging boreholes for heat storage because of the enormous heat capacity of the earth. -- Highlights: → We study four working modes of a solar-assisted ground coupled heat pump. → The heating performance is in direct relation with the borehole temperature. → Solar-assisted heating elevates borehole temperature and system performance. → The system shows higher efficiency over traditional heating systems in cold areas. → Solar heat is not suggested for high temperature seasonal storage.

Exergy and Energy Analysis of Low Temperature District Heating Network

DEFF Research Database (Denmark)

Li, Hongwei; Svendsen, Svend

is in line with a pilot project that is carrying out in Denmark with network supply/return temperature at 55oC/25 oC. The consumer domestic hot water (DHW) demand is supplied with a special designed district heating (DH) storage tank. The space heating (SH) demand is supplied with a low temperature radiator......Low temperature district heating (LTDH) with reduced network supply and return temperature provides better match of the low quality building thermal demand and the low quality waste heat supply. In this paper, an exemplary LTDH network was designed for 30 low energy demand residential houses, which....... The network thermal and hydraulic conditions were simulated under steady state with an in-house district heating network design and simulation code. Through simulation, the overall system energetic and exergetic efficiencies were calculated and the exergy losses for the major district heating system...

Impact of energy storage in buildings on electricity demand side management

International Nuclear Information System (INIS)

Qureshi, Waqar A.; Nair, Nirmal-Kumar C.; Farid, Mohammad M.

2011-01-01

Research highlights: → Phase change material (PCM) application for space heating has been implemented and assessed for built environment. → Real-Time Pricing (RTP) is assessed as tool to implement Demand Side Management programs effectively. → Two buildings, with and without PCM, have been compared for space heating using RTP in functional electricity market. → PCM found to offer peak load shifting, energy conservation, and reduction in price of electricity. -- Abstract: This paper assesses impact of using phase change materials (PCM) in buildings to leverage its thermal energy storage capability. The emphasis is from an electricity demand side perspective with case studies that incorporates wholesale electricity market data of New Zealand. The results presented in this paper show that for space heating application significant advantages could be obtained using PCM built structures. These positive impacts include peak load shifting, energy conservation and reduction in peak demand for network line companies and potential reduction in electricity consumption and savings for residential customers. This paper uses a testing facility that consists of two identically designed and shaped offices built at Tamaki Campus location of the University of Auckland, New Zealand. The walls and ceilings of one office are finished with ordinary gypsum boards while the interior of the other office is finished with PCM impregnated gypsum boards. Controlled heating facility is provided in both the offices for maintaining temperature within the range of human comfort. This facility is equipped with advanced data acquisition equipment for data monitoring and archiving both locally within the offices and also remotely. Through actual observations and analysis this paper demonstrates two major impacts of DSM. First, the application of phase change material (PCM) in building environment enabling efficient thermal storage to achieve some reduction in the overall electrical energy

Solar system for domestic hot water and space heating

Energy Technology Data Exchange (ETDEWEB)

Weiss, W. [Arbeitsgemeinschaf Erneubare Energie, Gleisdorf (Austria)

1997-12-31

The solar thermal markets, different types of solar systems for hot water and space heating, the dimensioning and the components of solar heating systems, the properties of the systems are reviewed in this presentation

Solar system for domestic hot water and space heating

Energy Technology Data Exchange (ETDEWEB)

Weiss, W [Arbeitsgemeinschaf Erneubare Energie, Gleisdorf (Austria)

1998-12-31

The solar thermal markets, different types of solar systems for hot water and space heating, the dimensioning and the components of solar heating systems, the properties of the systems are reviewed in this presentation

Heat pump system with selective space cooling

Science.gov (United States)

Pendergrass, J.C.

1997-05-13

A reversible heat pump provides multiple heating and cooling modes and includes a compressor, an evaporator and heat exchanger all interconnected and charged with refrigerant fluid. The heat exchanger includes tanks connected in series to the water supply and a condenser feed line with heat transfer sections connected in counterflow relationship. The heat pump has an accumulator and suction line for the refrigerant fluid upstream of the compressor. Sub-cool transfer tubes associated with the accumulator/suction line reclaim a portion of the heat from the heat exchanger. A reversing valve switches between heating/cooling modes. A first bypass is operative to direct the refrigerant fluid around the sub-cool transfer tubes in the space cooling only mode and during which an expansion valve is utilized upstream of the evaporator/indoor coil. A second bypass is provided around the expansion valve. A programmable microprocessor activates the first bypass in the cooling only mode and deactivates the second bypass, and vice-versa in the multiple heating modes for said heat exchanger. In the heating modes, the evaporator may include an auxiliary outdoor coil for direct supplemental heat dissipation into ambient air. In the multiple heating modes, the condensed refrigerant fluid is regulated by a flow control valve. 4 figs.

Performance analysis of diesel engine heat pump incorporated with heat recovery

International Nuclear Information System (INIS)

Shah, N.N.; Huang, M.J.; Hewitt, N.J.

2016-01-01

Highlights: • Diesel engine heat pump with heat recovery. • Water-to-water source heat pump based on R134a. • Possibility for different flow temperature for heat distribution system. • Possible retrofit application in off-gas or weak electricity network area. • Potential to diversify use of fossil fuel, primary energy and CO_2 emission savings. - Abstract: This paper presents experimental study of diesel engine heat pump (DEHP) system to find potential as retrofit technology in off-gas or weak electricity network area to replace existing gas/oil/electric heating system in domestic sector. Test set-up of diesel engine driven water-to-water heat pump system was built which included heat recovery arrangement from the engine coolant & exhaust gas. The system was designed to meet typical house heating demand in Northern Ireland. Performance of DEHP was evaluated to meet house-heating demand at different flow temperature (35, 45, 55 & 65 °C), a typical requirement of underfloor space heating, medium/high temperature radiators and domestic hot water. The performance was evaluated against four-evaporator water inlet temperature (0, 5, 10 & 15 °C) and at three different engine speed 1600, 2000 & 2400 rpm. Experiment results were analysed in terms of heating/cooling capacity, heat recovery, total heat output, primary energy ratio (PER), isentropic efficiency, etc. Test results showed that DEHP is able to meet house-heating demand with help of heat recovery with reduced system size. Heat recovery contributed in a range of 22–39% in total heat output. It is possible to achieve high flow temperature in a range of 74 °C with help of heat recovery. Overall system PER varied in a range of 0.93–1.33. Speed increment and flow temperature has significant impact on heat recovery, total heat output and PER. A case scenario with different flow temperature to match house-heating demand has been presented to show working potential with different heat distribution system

Measure Guideline. Combination Forced-Air Space and Tankless Domestic Hot Water Heating Systems

Energy Technology Data Exchange (ETDEWEB)

Rudd, Armin [Building Science Corporation Industry Team (BSC), Somerville, MA (United States)

2012-08-01

This document describes design and application guidance for combination space and tankless domestic hot water heating systems (combination systems) used in residential buildings, based on field evaluation, testing, and industry meetings conducted by Building Science Corporation. As residential building enclosure improvements continue to drive heating loads down, using the same water heating equipment for both space heating and domestic water heating becomes attractive from an initial cost and space-saving perspective. This topic is applicable to single- and multi-family residential buildings, both new and retrofitted.

Geothermal space/water heating for Mammoth Lakes Village, California. Quarterly technical progress report, 13 December 1976-12 March 1977

Energy Technology Data Exchange (ETDEWEB)

Sims, A.V.; Racine, W.C.

1977-01-01

During the second three months of this feasibility study to determine the technical, economic and environmental feasibility of heating Mammoth Lakes Village, California using geothermal energy, the following work was accomplished. A saturation survey of the number and types of space and water heaters currently in use in the Village was completed. Electric energy and ambient temperature metering equipment was installed. Peak heating demand for Mammoth Lakes was estimated for the years 1985, 1990 and 2000. Buildings were selected which are considered typical of Mammoth Lakes in terms of their heating systems to be used in estimating the cost of installing hydronic heating systems in Mammoth. Block diagrams and an order of magnitude cost comparison were prepared for high-temperature and low-temperature geothermal district heating systems. Models depicting a geothermal district heating system and a geothermal-electric power plant were designed, built and delivered to ERDA in Washington. Local input to the feasibility study was obtained from representatives of the State of California Departments of Transportation and Fish and Game, US Forest Service, and Mono County Planning Department.

Economic feasibility of solar water and space heating.

Science.gov (United States)

Bezdek, R H; Hirshberg, A S; Babcock, W H

1979-03-23

The economic feasibility in 1977 and 1978 of solar water and combined water and space heating is analyzed for single-family detached residences and multi-family apartment buildings in four representative U.S. cities: Boston, Massachusetts; Washington, D.C.; Grand Junction, Colorado; and Los Angeles, California. Three economic decision criteria are utilized: payback period, years to recovery of down payment, and years to net positive cash flow. The cost competitiveness of the solar systems compared to heating systems based on electricity, fuel oil, and natural gas is then discussed for each city, and the impact of the federal tax credit for solar energy systems is assessed. It is found that even without federal incentives some solar water and space heating systems are competitive. Enactment of the solar tax credit, however, greatly enhances their competitiveness. The implications of these findings for government tax and energy pricing policies are discussed.

Space Launch System Base Heating Test: Experimental Operations & Results

Science.gov (United States)

Dufrene, Aaron; Mehta, Manish; MacLean, Matthew; Seaford, Mark; Holden, Michael

2016-01-01

NASA's Space Launch System (SLS) uses four clustered liquid rocket engines along with two solid rocket boosters. The interaction between all six rocket exhaust plumes will produce a complex and severe thermal environment in the base of the vehicle. This work focuses on a recent 2% scale, hot-fire SLS base heating test. These base heating tests are short-duration tests executed with chamber pressures near the full-scale values with gaseous hydrogen/oxygen engines and RSRMV analogous solid propellant motors. The LENS II shock tunnel/Ludwieg tube tunnel was used at or near flight duplicated conditions up to Mach 5. Model development was based on the Space Shuttle base heating tests with several improvements including doubling of the maximum chamber pressures and duplication of freestream conditions. Test methodology and conditions are presented, and base heating results from 76 runs are reported in non-dimensional form. Regions of high heating are identified and comparisons of various configuration and conditions are highlighted. Base pressure and radiometer results are also reported.

Ventilation with heat recovery

DEFF Research Database (Denmark)

Tommerup, Henrik M.; Svendsen, Svend

2005-01-01

This paper presents the experiences from the use of ventilation with heat recovery in several experimental single-family houses developed and built within the last four years to meet the new Danish energy requirements of 2005. Included are descriptions of the ventilation system components...... and the main functional demands as well as measurements of the thermal efficiency, electricity consumptions and building air tightness. The paper addresses the aspects of minimizing the heat loss from the duct system and the heat recovery unit (when placed in an unheated attic space) in order to obtain...

Capillary-Driven Heat Transfer Experiment: Keeping It Cool in Space

Science.gov (United States)

Lekan, Jack F.; Allen, Jeffrey S.

1998-01-01

Capillary-pumped loops (CPL's) are devices that are used to transport heat from one location to another--specifically to transfer heat away from something. In low-gravity applications, such as satellites (and possibly the International Space Station), CPL's are used to transfer heat from electrical devices to space radiators. This is accomplished by evaporating one liquid surface on the hot side of the CPL and condensing the vapor produced onto another liquid surface on the cold side. Capillary action, the phenomenon that causes paper towels to absorb spilled liquids, is used to "pump" the liquid back to the evaporating liquid surface (hot side) to complete the "loop." CPL's require no power to operate and can transfer heat over distances as large as 30 ft or more. Their reliance upon evaporation and condensation to transfer heat makes them much more economical in terms of weight than conventional heat transfer systems. Unfortunately, they have proven to be unreliable in space operations, and the explanation for this unreliability has been elusive. The Capillary-Driven Heat Transfer (CHT) experiment is investigating the fundamental fluid physics phenomena thought to be responsible for the failure of CPL's in low-gravity operations. If the failure mechanism can be identified, then appropriate design modifications can be developed to make capillary phase-change heat-transport devices a more viable option in space applications. CHT was conducted onboard the Space Shuttle Columbia during the first Microgravity Science Laboratory (MSL-1) mission, STS-94, which flew from July 1 to 17, 1997. The CHT glovebox investigation, which was conceived by Dr. Kevin Hallinan and Jeffrey Allen of the University of Dayton, focused on studying the dynamics associated with the heating and cooling at the evaporating meniscus within a capillary phase-change device in a low-gravity environment. The CHT experimental hardware was designed by a small team of engineers from Aerospace Design

A novel algorithm for demand-control of a single-room ventilation unit with a rotary heat exchanger

DEFF Research Database (Denmark)

Smith, Kevin Michael; Jansen, Anders Lund; Svendsen, Svend

in the indoor environment. Based on these values, a demand-control algorithm varies fan speeds to change airflow rates and varies the rotational speed of the heat exchanger to modulate heat and moisture recovery. The algorithm varies airflow rates to provide free cooling and limit CO2 concentrations and varies...... moisture recovery by varying the rotational speed and then safely unbalances airflows in a worst-case scenario. In the algorithm, frost protection and minimum supply temperature take the highest priority and override other controls. This paper documents the proposed demand control algorithm and analyses...... its impacts on compliance of building regulations in Denmark. The paper presents an algorithm that manufacturers can program into their controls. The commercially available single-room ventilation unit with a rotary heat exchanger uses this algorithm coded in the C language. Future work will document...

Micro tube heat exchangers for Space, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Mezzo fabricates micro tube heat exchangers for a variety of applications, including aerospace, automotive racing, Department of Defense ground vehicles, economizers...

Investigations of Intelligent Solar Heating Systems for Single Family House

DEFF Research Database (Denmark)

Andersen, Elsa; Chen, Ziqian; Fan, Jianhua

2014-01-01

Three differently designed intelligent solar heating systems are investigated experimentally in a test facility. The systems provide all the needed yearly heating demand in single family houses. The systems are based on highly stratified tanks with variable auxiliary heated volumes. The tank is a......, the control strategy of intelligent solar heating systems is investigated and the yearly auxiliary energy use of the systems and the electricity price for supplying the consumers with domestic hot water and space heating are calculated....... systems.The system will be equipped with an intelligent control system where the control of the electrical heating element(s)/heat pump is based on forecasts of the variable electricity price, the heating demand and the solar energy production.By means of numerical models of the systems made in Trnsys......Three differently designed intelligent solar heating systems are investigated experimentally in a test facility. The systems provide all the needed yearly heating demand in single family houses. The systems are based on highly stratified tanks with variable auxiliary heated volumes. The tank...

Heat-pipe development for the SPAR space-power system

International Nuclear Information System (INIS)

Ranken, W.A.

1981-01-01

The SPAR space power system design is based on a high temperature fast spectrum nuclear reactor that furnishes heat to a thermoelectric conversion system to generate an electrical power output of 100 kW/sub (e)/. An important feature of this design is the use of alkali metal heat pipes to provide redundant, reliable, and low-loss heat transfer at high temperature. Three sets of heat pipes are used in the system. These include sodium/molybdenum heat pipes to transfer heat from the reactor core to the conversion system, potassium/niobium heat pipes to couple the conversion system to the radiator in a redundant manner, and potassium/titanium heat pipes to distribute rejected heat throughout the radiator surface. The designs of these units are discussed and fabrication methods and testing results are described. 12 figures

Micro-Channel Embedded Pulsating Heat Pipes, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — As the need for thermal control technology becomes more demanding Micro-Channel Embedded Pulsating Heat Pipes (ME-PHPs) represents a sophisticated and enabling...

Evaluation of Advanced Models for PAFS Condensation Heat Transfer in SPACE Code

Energy Technology Data Exchange (ETDEWEB)

Bae, Byoung-Uhn; Kim, Seok; Park, Yu-Sun; Kang, Kyung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Ahn, Tae-Hwan; Yun, Byong-Jo [Pusan National University, Busan (Korea, Republic of)

2015-10-15

The PAFS (Passive Auxiliary Feedwater System) is operated by the natural circulation to remove the core decay heat through the PCHX (Passive Condensation Heat Exchanger) which is composed of the nearly horizontal tubes. For validation of the cooling and operational performance of the PAFS, PASCAL (PAFS Condensing Heat Removal Assessment Loop) facility was constructed and the condensation heat transfer and natural convection phenomena in the PAFS was experimentally investigated at KAERI (Korea Atomic Energy Research Institute). From the PASCAL experimental result, it was found that conventional system analysis code underestimated the condensation heat transfer. In this study, advanced condensation heat transfer models which can treat the heat transfer mechanisms with the different flow regimes in the nearly horizontal heat exchanger tube were analyzed. The models were implemented in a thermal hydraulic safety analysis code, SPACE (Safety and Performance Analysis Code for Nuclear Power Plant), and it was evaluated with the PASCAL experimental data. With an aim of enhancing the prediction capability for the condensation phenomenon inside the PCHX tube of the PAFS, advanced models for the condensation heat transfer were implemented into the wall condensation model of the SPACE code, so that the PASCAL experimental result was utilized to validate the condensation models. Calculation results showed that the improved model for the condensation heat transfer coefficient enhanced the prediction capability of the SPACE code. This result confirms that the mechanistic modeling for the film condensation in the steam phase and the convection in the condensate liquid contributed to enhance the prediction capability of the wall condensation model of the SPACE code and reduce conservatism in prediction of condensation heat transfer.

Price and income elasticities of residential energy demand in Germany

International Nuclear Information System (INIS)

Schulte, Isabella; Heindl, Peter

2017-01-01

We apply a quadratic expenditure system to estimate price and expenditure elasticities of residential energy demand (electricity and heating) in Germany. Using official expenditure data from 1993 to 2008, we estimate an expenditure elasticity for electricity of 0.3988 and of 0.4055 for space heating. The own price elasticity for electricity is −0.4310 and −0.5008 in the case of space heating. Disaggregation of households by expenditure and socio-economic composition reveals that the behavioural response to energy price changes is weaker (stronger) for low-income (top-income) households. There are considerable economies of scale in residential energy use but scale effects are not well approximated by the new OECD equivalence scale. Real increases in energy prices show a regressive pattern of incidence, implying that the welfare consequences of direct energy taxation are larger for low income households. The application of zero-elasticities in assessments of welfare consequences of energy taxation strongly underestimates potential welfare effects. The increase in inequality is 22% smaller when compared to the application of disaggregated price and income elasticities as estimated in this paper. - Highlights: • We estimate price, income, and expenditure elasticities for residential energy demand in Germany. • We differentiate elasticities by income groups and household type. • Electricity and space heating are necessary goods since the expenditure elasticities are smaller than unity. • Low-income households show a weaker reaction to changing prices when compared to high-income households. • Direct energy taxation has regressive effects, meaning that larger burdens fall upon low-income households.

Heat Roadmap Europe

DEFF Research Database (Denmark)

Connolly, David

2017-01-01

This paper compares the electricity, heating, and cooling sectors at national level for various European countries. Annual energy demands are compared for all 28 EU countries, while peak hourly demands are compared for four countries that vary significantly. The results indicate that the heat...... demand is currently the largest of the three demand types considered in terms of both annual and peak demands: it is the largest annual demand in 25 of the 28 EU countries, and it represents the largest peak demand in all four countries analysed. Electricity, heating, and cooling demands are all likely...... that the demand for electricity could double compared to today, depending on how these changes occur. Considering the scale of additional electricity required to electrify future heating and cooling demands, heat pumps should be prioritised over electric heating and other alternatives, such as district heating...

Wind Turbines and Heat Pumps. Balancing wind power fluctuations using flexible demand

International Nuclear Information System (INIS)

Warmer, C.J.; Hommelberg, M.P.F.; Kamphuis, I.G.; Derszi, Z.; Kok, J.K.

2007-01-01

In order to overcome portfolio imbalance for traders of variable power from wind we have built an 'Imbalance Reduction System' (IRS) and performed a real-world field test with it, in which imbalance is minimized within a real-time electricity market portfolio, consisting of wind power and industrial and residential consumers and producers (Combined Heat and Power for district heating; residential heat pumps; industrial cold store; emergency generators). IRS uses the PowerMatcher concept, a coordination system for supply and demand of electricity in a which multi-agent system is combined with microeconomic principles. IRS appears to offer opportunities for embedding less predictable generators such as wind power more smoothly in the portfolio. We describe the context and operation of the Imbalance Reduction System and discuss a number of results from the performed field test. Also we introduce a business model for the balance responsible party, based on the e3-value method

A new test procedure to evaluate the performance of substations for collective heating systems

Science.gov (United States)

Baetens, Robin; Verhaert, Ivan

2017-11-01

The overall heat demand of a single dwelling, existing out of space heating and domestic hot water production, decreases due to higher insulation rates. Because of this, investing in efficient and renewable heat generation becomes less interesting. Therefore, to incorporate renewables or residual heat on a larger scale, district heating or collective heating systems grow in importance. Within this set-up, the substation is responsible for the interaction between local demand for comfort and overall energy performance of the collective heating system. Many different configurations of substations exist, which influence both local comfort and central system performance. Next to that, also hybrids exist with additional local energy input. To evaluate performance of such substations, a new experimental-based test procedure is developed in order to evaluate these different aspects, characterized by the two roles a substation has, namely as heat generator and as heat consumer. The advantage of this approach is that an objective comparison between individual and central systems regarding performance on delivering local comfort can be executed experimentally. The lab set-up consists out of three different subsystems, namely the central system, the domestic hot water consumption and the local space heating. The central system can work with different temperature regimes and control strategies, as these aspects have proven to have the largest influence on actual performance. The domestic hot water system is able to generate similar tap profiles according to eco-design regulation for domestic hot water generation. The space heating system is able to demand a modular heat load.

A new test procedure to evaluate the performance of substations for collective heating systems

Directory of Open Access Journals (Sweden)

Baetens Robin

2017-01-01

Full Text Available The overall heat demand of a single dwelling, existing out of space heating and domestic hot water production, decreases due to higher insulation rates. Because of this, investing in efficient and renewable heat generation becomes less interesting. Therefore, to incorporate renewables or residual heat on a larger scale, district heating or collective heating systems grow in importance. Within this set-up, the substation is responsible for the interaction between local demand for comfort and overall energy performance of the collective heating system. Many different configurations of substations exist, which influence both local comfort and central system performance. Next to that, also hybrids exist with additional local energy input. To evaluate performance of such substations, a new experimental-based test procedure is developed in order to evaluate these different aspects, characterized by the two roles a substation has, namely as heat generator and as heat consumer. The advantage of this approach is that an objective comparison between individual and central systems regarding performance on delivering local comfort can be executed experimentally. The lab set-up consists out of three different subsystems, namely the central system, the domestic hot water consumption and the local space heating. The central system can work with different temperature regimes and control strategies, as these aspects have proven to have the largest influence on actual performance. The domestic hot water system is able to generate similar tap profiles according to eco-design regulation for domestic hot water generation. The space heating system is able to demand a modular heat load.

Investigation of a low flow solar heating system for space heating and domestic hot water supply for Aidt Miljø A/S

DEFF Research Database (Denmark)

Vejen, Niels Kristian

1997-01-01

A low flow solar heating system for space heating and domestic hot water supply from Aidt Miljø A/Swas tested in a laboratory test facility.......A low flow solar heating system for space heating and domestic hot water supply from Aidt Miljø A/Swas tested in a laboratory test facility....

A comprehensive assessment of the life cycle energy demand of passive houses

International Nuclear Information System (INIS)

Stephan, André; Crawford, Robert H.; Myttenaere, Kristel de

2013-01-01

Highlights: • The life cycle energy demand of a passive house (PH) is measured over 100 years. • Embodied, operational and user transport energy demand are considered. • Embodied energy represents the highest energy consumption in all variations. • A PH might not save energy compared to a standard house. • A poorly insulated city apartment can use less energy than a best case suburban PH. - Abstract: Certifications such as the Passive House aim to reduce the final space heating energy demand of residential buildings. The latter are responsible for a significant share of final energy consumption in Europe of which nearly 70% is associated with space conditioning, notably heating. The improvement of the energy efficiency of residential buildings, in terms of space heating, can therefore reduce their total energy demand. However, most certifications totally overlook other energy requirements associated with residential buildings. Studies on passive houses do not take into consideration the embodied energy required to manufacture the building materials, especially the large amount of insulation required to achieve high operational efficiencies. At an urban scale, most passive houses are single family detached houses located in low density suburbs with a high car usage, resulting in considerable transport related energy demand. This paper analyses the total life cycle energy demand of a typical Belgian passive house, comprising embodied, operational and transport energy. It relies on a comprehensive technique developed by Stephan et al. [1] and conducts a parametric analysis as well as a comparison to alternative building types. Results show that current building energy efficiency certifications might not ensure a lower energy demand and can, paradoxically result in an increased energy consumption because of their limited scope. More comprehensive system boundaries should be used to make sure that net energy savings do occur. The embodied energy of passive

Investigation of a solar heating system for space heating and domestic hot water supply for Sol&Træ A.m.b.a

DEFF Research Database (Denmark)

Vejen, Niels Kristian

1999-01-01

A solar heating system for space heating and domestic hot water supply from "Sol&Træ A.m.b.a." was tested in a laboratory test facility.......A solar heating system for space heating and domestic hot water supply from "Sol&Træ A.m.b.a." was tested in a laboratory test facility....

Direct utilization of geothermal energy for space and water heating at Marlin, Texas. Final report

Energy Technology Data Exchange (ETDEWEB)

Conover, M.F.; Green, T.F.; Keeney, R.C.; Ellis, P.F. II; Davis, R.J.; Wallace, R.C.; Blood, F.B.

1983-05-01

The Torbett-Hutchings-Smith Memorial Hospital geothermal heating project, which is one of nineteen direct-use geothermal projects funded principally by DOE, is documented. The five-year project encompassed a broad range of technical, institutional, and economic activities including: resource and environmental assessments; well drilling and completion; system design, construction, and monitoring; economic analyses; public awareness programs; materials testing; and environmental monitoring. Some of the project conclusions are that: (1) the 155/sup 0/F Central Texas geothermal resource can support additional geothermal development; (2) private-sector economic incentives currently exist, especially for profit-making organizations, to develop and use this geothermal resource; (3) potential uses for this geothermal resource include water and space heating, poultry dressing, natural cheese making, fruit and vegetable dehydrating, soft-drink bottling, synthetic-rubber manufacturing, and furniture manufacturing; (4) high maintenance costs arising from the geofluid's scaling and corrosion tendencies can be avoided through proper analysis and design; (5) a production system which uses a variable-frequency drive system to control production rate is an attractive means of conserving parasitic pumping power, controlling production rate to match heating demand, conserving the geothermal resource, and minimizing environmental impacts.

Characterizing U.S. Heat Demand for Potential Application of Geothermal Direct Use: Preprint

Energy Technology Data Exchange (ETDEWEB)

McCabe, Kevin; Gleason, Michael; Reber, Tim; Young, Katherine R.

2016-10-01

In this paper, we assess the U.S. demand for low-temperature thermal energy at the county resolution for four major end-use sectors: residential buildings, commercial buildings, manufacturing facilities, and agricultural facilities. Existing, publicly available data on the U.S. thermal demand market are characterized by coarse spatial resolution, with assessments typically at the state-level or larger. For many uses, these data are sufficient; however, our research was motivated by an interest in assessing the potential demand for direct use (DU) of low-temperature (30 degrees to 150 degrees C) geothermal heat. The availability and quality of geothermal resources for DU applications are highly spatially heterogeneous; therefore, to assess the potential market for these resources, it is necessary to understand the spatial variation in demand for low-temperature resources at a local resolution. This paper presents the datasets and methods we used to develop county-level estimates of the thermal demand for the residential, commercial, manufacturing, and agricultural sectors. Although this analysis was motivated by an interest in geothermal energy deployment, the results are likely to have broader applications throughout the energy industry. The county-resolution thermal demand data developed in this study for four major U.S. sectors may have far-reaching implications for building technologies, industrial processes, and various distributed renewable energy thermal resources (e.g. biomass, solar).

Characterizing U.S. Heat Demand Market for Potential Application of Geothermal Direct Use

Energy Technology Data Exchange (ETDEWEB)

McCabe, Kevin; Gleason, Michael; Reber, Tim; Young, Katherine R.

2017-05-01

In this paper, we assess the U.S. demand for low-temperature thermal energy at the county resolution for four major end-use sectors: residential buildings, commercial buildings, manufacturing facilities, and agricultural facilities. Existing, publicly available data on the U.S. thermal demand market are characterized by coarse spatial resolution, with assessments typically at the state-level or larger. For many uses, these data are sufficient; however, our research was motivated by an interest in assessing the potential demand for direct use (DU) of low-temperature (30 degrees to 150 degrees C) geothermal heat. The availability and quality of geothermal resources for DU applications are highly spatially heterogeneous; therefore, to assess the potential market for these resources, it is necessary to understand the spatial variation in demand for low-temperature resources at a local resolution. This paper presents the datasets and methods we used to develop county-level estimates of the thermal demand for the residential, commercial, manufacturing, and agricultural sectors. Although this analysis was motivated by an interest in geothermal energy deployment, the results are likely to have broader applications throughout the energy industry. The county-resolution thermal demand data developed in this study for four major U.S. sectors may have far-reaching implications for building technologies, industrial processes, and various distributed renewable energy thermal resources (e.g. biomass, solar).

Titanium Loop Heat Pipes for Space Nuclear Radiators, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project will develop titanium Loop Heat Pipes (LHPs) that can be used in low-mass space nuclear radiators, such as...

Solar water heater for NASA's Space Station

Science.gov (United States)

Somers, Richard E.; Haynes, R. Daniel

1988-01-01

The feasibility of using a solar water heater for NASA's Space Station is investigated using computer codes developed to model the Space Station configuration, orbit, and heating systems. Numerous orbit variations, system options, and geometries for the collector were analyzed. Results show that a solar water heater, which would provide 100 percent of the design heating load and would not impose a significant impact on the Space Station overall design is feasible. A heat pipe or pumped fluid radial plate collector of about 10-sq m, placed on top of the habitat module was found to be well suited for satisfying water demand of the Space Station. Due to the relatively small area required by a radial plate, a concentrator is unnecessary. The system would use only 7 to 10 percent as much electricity as an electric water-heating system.

Accident analysis of heat pipe cooled and AMTEC conversion space reactor system

International Nuclear Information System (INIS)

Yuan, Yuan; Shan, Jianqiang; Zhang, Bin; Gou, Junli; Bo, Zhang; Lu, Tianyu; Ge, Li; Yang, Zijiang

2016-01-01

Highlights: • A transient analysis code TAPIRS for HPS has been developed. • Three typical accidents are analyzed using TAPIRS. • The reactor system has the self-stabilization ability under accident conditions. - Abstract: A space power with high power density, light weight, low cost and high reliability is of crucial importance to future exploration of deep space. Space reactor is an excellent candidate because of its unique characteristics of high specific power, low cost, strong environment adaptability and so on. Among all types of space reactors, heat pipe cooled space reactor, which adopts the passive heat pipe (HP) as core cooling component, is considered as one of the most promising choices and is widely studied all over the world. This paper develops a transient analysis code (TAPIRS) for heat pipe cooled space reactor power system (HPS) based on point reactor kinetics model, lumped parameter core heat transfer model, combined HP model (self-diffusion model, flat-front startup model and network model), energy conversion model of Alkali Metal Thermal-to-Electric Conversion units (AMTEC), and HP radiator model. Three typical accidents, i.e., control drum failure, AMTEC failure and partial loss of the heat transfer area of radiator are then analyzed using TAPIRS. By comparing the simulation results of the models and steady state with those in the references, the rationality of the models and the solution method is validated. The results show the following. (1) After the failure of one set of control drums, the reactor power finally reaches a stable value after two local peaks under the temperature feedback. The fuel temperature rises rapidly, however it is still under safe limit. (2) The fuel temperature is below a safe limit under the AMTEC failure and partial loss of the heat transfer area of radiator. This demonstrates the rationality of the system design and the potential applicability of the TAPIRS code for the future engineering application of

Power System Integration of Flexible Demand in the Low Voltage Network

DEFF Research Database (Denmark)

Thavlov, Anders

, it is natural to consider electricity consumption from households as an integrated part of a potential flexible demand side in the future power system. However, as an individual unit a single household is not able to generate a large impact in the power system. Therefore, a mechanism is needed which can...... is even greater as almost 50% of the electricity consumption in households is utilised for space heating and cooling and for heating of domestic hot water. Consequently, there exists a significant potential in the integration of power consumption for heating purposes in households for demand response...... of electricity on the Nordic energy exchange, Nord Pool, or alternatively the flexibility can be sold as an ancillary service to the transmission system operator. In this way, the electricity consumption in households are indirectly integrated into the power market, through the virtual power plant...

Heat of Fusion Storage with High Solar Fraction for Solar Low Energy Buildings

DEFF Research Database (Denmark)

Schultz, Jørgen Munthe; Furbo, Simon

The paper presents the results of a theoretical investigation of use of phase change materials (PCM’s) with active use of super cooling as a measure for obtaining partly heat loss free seasonal storages for solar combi-systems with 100% coverage of the energy demand of both space heating and dome......The paper presents the results of a theoretical investigation of use of phase change materials (PCM’s) with active use of super cooling as a measure for obtaining partly heat loss free seasonal storages for solar combi-systems with 100% coverage of the energy demand of both space heating...... and domestic hot water. The work is part of the IEA Solar Heating & Cooling Programme Task 32 “Advanced Storage Concepts for Solar Buildings”. The investigations are based on a newly developed TRNSYS type for simulation of a PCM-storage with controlled super-cooling. The super-cooling makes it possible to let...... storage parts already melted to cool down to surrounding temperature without solidification in which state that part of the storage will be heat loss free but still will hold the latent heat in form of the heat of fusion. At the time of energy demand the solidification of the super-cooled storage part...

Experimental results of a 3 k Wh thermochemical heat storage module for space heating application

NARCIS (Netherlands)

Finck, C.J.; Henquet, E.M.R.; Soest, C.F.L. van; Oversloot, H.P.; Jong, A.J. de; Cuypers, R.; Spijker, J.C. van 't

2014-01-01

A 3 kWh thermochemical heat storage (TCS) module was built as part of an all-in house system implementation focusing on space heating application at a temperature level of 40 ºC and a temperature lift of 20 K. It has been tested and measurements showed a maximum water circuit temperature span

Investigation af a solar heating system for space heating and domestic hot water supply with a high degree of coverage

DEFF Research Database (Denmark)

Vejen, Niels Kristian

1999-01-01

A solar storage tank for space heating and domestic hot water supply was designed and testet in af laboratory test facility.......A solar storage tank for space heating and domestic hot water supply was designed and testet in af laboratory test facility....

Investigation of a heat storage for a solar heating system for combined space heating and domestic hot water supply for homeowner´s association "Bakken"

DEFF Research Database (Denmark)

Vejen, Niels Kristian

1998-01-01

A heat storage for a solar heating system for combined space heating and domestic hot water supply was tested in a laboratory test facility.The heat storage consist of a mantle tank with water for the heating system and of a hot water tank, which by means of thermosyphoning is heated by the water...

Linear programming control of a group of heat pumps

NARCIS (Netherlands)

Fink, J.; van Leeuwen, Richard Pieter; Hurink, Johann L.; Smit, Gerardus Johannes Maria

2015-01-01

For a new district in the Dutch city Meppel, a hybrid energy concept is developed based on bio-gas co-generation. The generated electricity is used to power domestic heat pumps which supply thermal energy for domestic hot water and space heating demand of households. In this paper, we investigate

Transient heat pipe investigations for space power systems

International Nuclear Information System (INIS)

Merrigan, M.A.; Keddy, E.S.; Sena, J.T.

1985-01-01

A 4-meter long, high temperature, high power, molybdenum-lithium heat pipe has been fabricated and tested in transient and steady state operation at temperatures to 1500 K. Maximum power throughput during the tests was approximately 37 kW/cm 2 for the 1.4 cm diameter vapor space of the annular wick heat pipe. The evaporator flux density for the tests was 150.0 W/cm 2 over a length of 40 cm. Condenser length was approximately 3.0 m with radiant heat rejection from the condenser to a coaxial, water cooled radiation calorimeter. A variable radiation shield, controllable from the outside of the vacuum enclosure, was used to vary the load on the heat pipe during the tests. 1 ref., 9 figs

Heat Roadmap Europe 1

DEFF Research Database (Denmark)

Connolly, David; Mathiesen, Brian Vad; Østergaard, Poul Alberg

2012-01-01

Heat Roadmap Europe (Pre-study 1) investigates the role of district heating in the EU27 energy system by mapping local conditions across Europe, identifying the potential for district heating expansion, and subsequently simulating the potential resource in an hourly model of the EU27 energy system....... In 2010, approximately 12% of the space heating demand in Europe is met by district heating, but in this study four alternative scenarios are considered for the EU27 energy system: 1. 2010 with 30% district heating 2. 2010 with 50% district heating 3. 2030 with 30% district heating 4. 2050 with 50......% district heating These scenarios are investigated in two steps. Firstly, district heating replaces individual boilers by converting condensing power plants to combined heat and power plants (CHP) to illustrate how district heating improves the overall efficiency of the energy system. In the second step...

DReAM: Demand Response Architecture for Multi-level District Heating and Cooling Networks

Energy Technology Data Exchange (ETDEWEB)

Bhattacharya, Saptarshi; Chandan, Vikas; Arya, Vijay; Kar, Koushik

2017-05-19

In this paper, we exploit the inherent hierarchy of heat exchangers in District Heating and Cooling (DHC) networks and propose DReAM, a novel Demand Response (DR) architecture for Multi-level DHC networks. DReAM serves to economize system operation while still respecting comfort requirements of individual consumers. Contrary to many present day DR schemes that work on a consumer level granularity, DReAM works at a level of hierarchy above buildings, i.e. substations that supply heat to a group of buildings. This improves the overall DR scalability and reduce the computational complexity. In the first step of the proposed approach, mathematical models of individual substations and their downstream networks are abstracted into appropriately constructed low-complexity structural forms. In the second step, this abstracted information is employed by the utility to perform DR optimization that determines the optimal heat inflow to individual substations rather than buildings, in order to achieve the targeted objectives across the network. We validate the proposed DReAM framework through experimental results under different scenarios on a test network.

Solar space heating for the Visitors Center, Stephens College, Columbia, Missouri

Science.gov (United States)

1980-01-01

The solar energy system located at the Visitors' Center on the Stephens College Campus, Columbia, Missouri is discussed. The system is installed in a four-story, 15,000 square foot building. The solar energy system is an integral design of the building and utilizes 176 hydronic flat plate collectors which use a 50 percent water ethylene blycol solution and water-to-water heat exchanger. Solar heated water is stored in a 5,000 gallon water storage tank located in the basement equipment room. A natural gas fired hot water boiler supplies hot water when the solar energy heat supply fails to meet the demand. The designed solar contribution is 71 percent of the heating load.

Laboratory Testing of Solar Combi System with Compact Long Term PCM Heat Storage

DEFF Research Database (Denmark)

Johansen, Jakob Berg; Englmair, Gerald; Dannemand, Mark

2016-01-01

To enable the transition from fossil fuels as a primary heat source for domestic hot water preparation and space heating solar thermal energy has great potential. The heat from the sun has the disadvantage that it is not always available when there is a demand. To solve this mismatch a thermal...... seasonal storage can be used to store excess heat from the summer to the winter when the demand is higher than the supply. Installing a long term thermal storage in a one family house it needs to be compact and sensible heat storages are not suitable. A latent heat storage with a phase change material (PCM...

Energetic and financial evaluation of solar assisted heat pump space heating systems

International Nuclear Information System (INIS)

Bellos, Evangelos; Tzivanidis, Christos; Moschos, Konstantinos; Antonopoulos, Kimon A.

2016-01-01

Highlights: • Four solar heating systems are presented in this work. • Various combinations between solar collectors and heat pumps are presented. • The systems are compared energetically and financially. • The use of PV and an air source heat pump is the best choice financially. • The use of PVT with a water source heat pump is the best solution energetically. - Abstract: Using solar energy for space heating purposes consists an alternative way for substituting fossil fuel and grid electricity consumption. In this study, four solar assisted heat pump heating systems are designed, simulated and evaluated energetically and financially in order to determine the most attractive solution. The use of PV collectors with air source heat pump is compared to the use of FPC, PVT and FPC with PV coupled with a water source heat pump. A sensitivity analysis for the electricity cost is conducted because of the great variety of this parameter over the last years. The final results proved that for electricity cost up to 0.23 €/kW h the use of PV coupled with an air source heat pump is the most sustainable solution financially, while for higher electricity prices the coupling of PVT with an water source heat pump is the best choice. For the present electricity price of 0.2 €/kW h, 20 m"2 of PV is able to drive the air source heat pump with a yearly solar coverage of 67% leading to the most sustainable solution. Taking into account energetic aspects, the use of PVT leads to extremely low grid electricity consumption, fact that makes this technology the most environmental friendly.

Analysis of the possibility to cover energy demand from renewable sources on the motive power of the heat pump in low-energy building

Directory of Open Access Journals (Sweden)

Knapik Maciej

2017-01-01

Full Text Available The article presents the problem of the demand for electricity for the heat pump and an analysis of the coverage of this demand by renewable energy sources such as wind turbines and photovoltaic cells, which generate electricity in low energy buildings. Low-energy and passive constructions are a result of introduction of new ideas in building design process. Their main objective is to achieve a significant reduction in demand for renewable primary energy, necessary to cover the needs of these buildings, mostly related to their heating, ventilation and domestic hot water This article presents the results of numerical analysis and calculations performed in MATLAB software, based on typical meteorological years. The results showed that renewable energy sources, can allow to cover a significant demand for electricity, that is required to power the heat pump it is economically justified.

Design of annual storage solar space heating systems

Energy Technology Data Exchange (ETDEWEB)

Hooper, F C; Cook, J D

1979-11-01

Design considerations for annual storage solar space heating systems are discussed. A simulation model for the performance of suh systems is described, and a method of classifying system configurations is proposed. It is shown that annual systems sized for unconstrained performance, with no unused collector or storage capacity, and no rejected heat, minimize solar acquisition costs. The optimal performance corresponds to the condition where the marginal storage-to-collector sizing ratio is equal to the corresponding marginal cost ratio.

Active charge, passive discharge floor space heating system

Energy Technology Data Exchange (ETDEWEB)

Salt, H.; Mahoney, K.J.

1987-01-01

This space heating system has a rockbed beneath and in contact with the floor of a dwelling, which is heated by radiation and convection from the floor. The ability of the heating system to maintain comfort conditions with no additional energy input is discussed and it is shown that the system is more suitable for use in mild climates than severe ones. Experimental work on horizontal air flow rockbeds is reported and shows that shallow beds can be designed in the same way as vertical air flow beds. The influence of natural convection on the effective thermal conductivity of the experimental rockbeds is reported.

Benefits and well-being perceived by green spaces users during heat waves

Directory of Open Access Journals (Sweden)

Dentamaro I

2010-07-01

Full Text Available In urban environments, green spaces have proven to act as ameliorating factors of some climatic features related to heat stress, reducing their effects and providing comfortable outdoor settings for people. In addition, green spaces have demonstrated greater capacity, compared with built-up areas, for promoting human health and well-being. In this paper, we present results of a study conducted in Italy with the general goal to contribute to the theoretical and empirical rationale for linking green spaces with well-being in urban environments. Specifically, the study focused on the physical and psychological benefits and the general well-being associated with the use of green spaces on people when heat stress episodes are more likely to occur. A questionnaire was set up and administered to users of selected green spaces in Italy (metropolitan area of Milan and Bari - n=400. Results indicate that longer and frequent visits of green spaces generate significant improvements of the perceived benefits and well-being among users. These results are consistent with the idea that the use of green spaces could alleviate the perception of thermal discomfort during periods of heat stress.

Convection heat transfer of closely-spaced spheres with surface blowing

Energy Technology Data Exchange (ETDEWEB)

Kleinstreuer, C. (North Carolina State Univ., Raleigh, NC (United States). Dept. of Mechanical and Aerospace Engineering); Chiang, H. (Thermofluid Technology Div., Industrial Technology Research Inst., Chutung (Taiwan, Province of China))

1993-05-01

A validated computer simulation model has been developed for the analysis of colinear spheres in a heated gas stream. Using the Galerkin finite element method, the steady-state Navier-Stokes and heat transfer equations have been solved describing laminar axisymmetric thermal flow past closely-spaced monodisperse spheres with fluid injection. Of interest are the coupled nonlinear interaction effects on the temperature fields and ultimately on the Nusselt number of each sphere for different free stream Reynolds numbers (20 [<=] Re [<=] 200) and intersphere distances (1.5 [<=] d[sub ij] [<=] 6.0) in the presence of surface blowing (0 [<=] v[sub b] [<=] 0.1). Fluid injection (i.e. blowing) and associated wake effects generate lower average heat transfer coefficients for each interacting sphere when the Reynolds number increases (Re > 100). Heat transfer is also reduced at small spacings especially for the second and third sphere. A Nusselt number correlation for each interacting (porous) sphere has been developed based on computer experiments. (orig.)

Heating and cooling energy demand in underground buildings : potential for saving in various climates and functions

NARCIS (Netherlands)

van Dronkelaar, C.; Costola, D.; Mangkuto, R.A.; Hensen, J.L.M.

2014-01-01

Underground buildings are pointed out as alternatives to conventional aboveground buildings for reducing total energy requirements, while alleviating land use and location problems. This paper investigates the potential in reducing the heating and cooling energy demand of underground buildings

Retrofitting Combined Space and Water Heating Systems: Laboratory Tests

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B.; Bohac, D.; Huelman, P.; Olson, R.; Hewitt, M.

2012-10-01

Better insulated and tighter homes can often use a single heating plant for both space and domestic water heating. These systems, called dual integrated appliances (DIA) or combination systems, can operate at high efficiency and eliminate combustion safety issues associated by using a condensing, sealed combustion heating plant. Funds were received to install 400 DIAs in Minnesota low-income homes. The NorthernSTAR DIA laboratory was created to identify proper system components, designs, operating parameters, and installation procedures to assure high efficiency of field installed systems. Tests verified that heating loads up to 57,000 Btu/hr can be achieved with acceptable return water temperatures and supply air temperatures.

Retrofitting Combined Space and Water Heating Systems. Laboratory Tests

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [NorthernStar Building America Partnership, St. Paul, MN (United States); Bohac, D. [NorthernStar Building America Partnership, St. Paul, MN (United States); Huelman, P. [NorthernStar Building America Partnership, St. Paul, MN (United States); Olsen, R. [NorthernStar Building America Partnership, St. Paul, MN (United States); Hewett, M. [NorthernStar Building America Partnership, St. Paul, MN (United States)

2012-10-01

Better insulated and tighter homes can often use a single heating plant for both space and domestic water heating. These systems, called dual integrated appliances (DIA) or combination systems, can operate at high efficiency and eliminate combustion safety issues associated by using a condensing, sealed combustion heating plant. Funds were received to install 400 DIAs in Minnesota low-income homes. The NorthernSTAR DIA laboratory was created to identify proper system components, designs, operating parameters, and installation procedures to assure high efficiency of field installed systems. Tests verified that heating loads up to 57,000 Btu/hr can be achieved with acceptable return water temperatures and supply air temperatures.

Residential space heating with wood burning stoves. Energy efficiency and indoor climate; Boligopvarmning ved braendefyring. Energieffektivitet og indeklima

Energy Technology Data Exchange (ETDEWEB)

Jensen, Ole Michael; Afshari, A.; Bergsoee, N.C.; Carvalho, R. [Miljoestyrelsen, Copenhagen (Denmark); Aalborg Univ.. Statens Byggeforskningsinstitut, Aalborg (Denmark))

2012-11-01

Two issues turn up concerning how to use wood-burning stoves in modern homes. The first is whether wood-burning stoves in future may still act as a genuine heat source, given that new and refurbished single-family houses retain the heat much better than older ones and therefore need less and less energy for space heating. The second issue is whether it will still be possible to use wood-burning stoves in modern houses where the air exchange is controlled by mechanical ventilation or possibly heat recovery. It is a question whether firing techniques can be developed that will work in airtight houses with mechanical ventilation and negative pressure, so that harmful particle emissions can be avoided. To illustrate the first issue, a field study was designed to look carefully at seven modern wood-burning stoves that were set up in six new houses and one older house and investigated, both in terms of firing and heat release. As a background for this part of the study, a heat balance calculation was made for each house. The question is, whether wood-burning stoves will also in the future have a role to play as a heating source. Modern houses grow ever tighter and only need to be supplied with a small quantity of heat. The new Danish Buildings Requirement, 2010 has resulted in a further reduction of 25 % of the energy demand, including the energy supply for heating. However, the new requirements imply that the heating season eventually become so short that a traditional central heating installation becomes superfluous. This means that by using the small amounts of wood cut in gardens and hedgerows of the neighbourhood, a wood-burning stove will, in principle, cover the heating demand. Therefore, the question is rather whether a wood-burning stove is manufactured that can successfully be adapted to new houses. As a consequence of this development, future stoves must be further scaled down in order to meet the heating demand of a modern low-energy house and the stoves must

Investigation and assessment of wall heat transfer correlations in SPACE code

International Nuclear Information System (INIS)

Kim, Jung Woo; Kim, Kyung Doo; Moon, Sang Ki; Choi, Ki Yong; Park, Hyun Sik

2010-06-01

SPACE, which is a safety analysis code for nuclear power plants, has been developed to analyze the multidimensional, two-component and three-field flow. This code can be applied to safety analysis for approval which is thermal-hydraulic analysis to support the nuclear power station design, establishment of accident ease strategy, development of operating guide line, experiment plan and analysis. To do so, SPACE code has 12 wall heat transfer mode and the corresponding models and correlations to deal with the physical heat transfer phenomenon in wall surface. In this report, the physical correlation models regarding the wall heat transfer are explained and their performance is assessed against several SET

Experimental Studies on Grooved Double Pipe Heat Exchanger with Different Groove Space

Science.gov (United States)

Sunu, P. W.; Arsawan, I. M.; Anakottapary, D. S.; Santosa, I. D. M. C.; Yasa, I. K. A.

2018-01-01

Experimental studies were performed on grooved double pipe heat exchanger (DPHE) with different groove space. The objective of this work is to determine optimal heat transfer parameter especially logarithmic mean temperature difference (LMTD). The document in this paper also provides the total heat observed by the cold fluid. The rectangular grooves were incised on outer surface of tube side with circumferential pattern and two different grooves space, namely 1 mm and 2 mm. The distance between grooves and the grooves high were kept constant, 8 mm and 0.3 mm respectively. The tube diameter is 20 mm and its made of aluminium. The shell is made of acrylic which has 28 mm in diameter. Water is used as the working fluid. Using counter flow scheme, the cold fluid flows in the annulus room of DPHE. The volume flowrate of hot fluid remains constant at 15 lpm. The volume flowrate of cold fluid were varied from 11 lpm to 15 lpm. Based on logarithmic mean temperature difference analysis, the LMTD of 1 mm grooves space was higher compared to that of 2 mm grooves space. The smaller grooves space has more advantage since the recirculating region are increased which essentially cause larger heat transfer enhancement.

Space qualification of high capacity grooved heat pipes

Energy Technology Data Exchange (ETDEWEB)

Dubois, M; Mullender, B; Druart, J [SABCA, Societe Anomyme Belgel de Construction Aeronautique (Belgium); Supper, W; Beddows, A [ESTEC-The (Netherlands)

1997-12-31

Based on the thermal requirements of the future telecommunication satellites, the development of a High Capacity Grooved Heat Pipe (HPG), was contracted by ESA to SABCA leading to an aluminium extruded heat pipe (outer diameter of 25 mm) based on a multi re-entrant grooves design. After an intensive acceptance test campaign whose results showed a good confidence in the design and the fulfillment of the required specifications of heat transport and on tilt capability (experimental maximum heat transport capability of 1500 Watt metres for a vapour temperature of 20 deg C), similar heat pipes have been developed with various outer diameters (11 mm, 15 mm and 20 mm) and with various shapes (circular outer shapes, integrated saddles). Several of these heat pipes were tested during two parabolic flight campaigns, by varying the heat loads during the micro-gravity periods. This HGP heat pipe family is now being submitted to a space qualification program according to ESA standards (ESA PSS-49), both in straight and bent configuration. Within this qualification, the heat pipes are submitted to an extended test campaign including environmental (random/sinus vibration, constant acceleration) and thermal tests (thermal performance, thermal cycle, thermal soak, ageing). (authors) 9 refs.

Space qualification of high capacity grooved heat pipes

Energy Technology Data Exchange (ETDEWEB)

Dubois, M.; Mullender, B.; Druart, J. [SABCA, Societe Anomyme Belgel de Construction Aeronautique (Belgium); Supper, W.; Beddows, A. [ESTEC-The (Netherlands)

1996-12-31

Based on the thermal requirements of the future telecommunication satellites, the development of a High Capacity Grooved Heat Pipe (HPG), was contracted by ESA to SABCA leading to an aluminium extruded heat pipe (outer diameter of 25 mm) based on a multi re-entrant grooves design. After an intensive acceptance test campaign whose results showed a good confidence in the design and the fulfillment of the required specifications of heat transport and on tilt capability (experimental maximum heat transport capability of 1500 Watt metres for a vapour temperature of 20 deg C), similar heat pipes have been developed with various outer diameters (11 mm, 15 mm and 20 mm) and with various shapes (circular outer shapes, integrated saddles). Several of these heat pipes were tested during two parabolic flight campaigns, by varying the heat loads during the micro-gravity periods. This HGP heat pipe family is now being submitted to a space qualification program according to ESA standards (ESA PSS-49), both in straight and bent configuration. Within this qualification, the heat pipes are submitted to an extended test campaign including environmental (random/sinus vibration, constant acceleration) and thermal tests (thermal performance, thermal cycle, thermal soak, ageing). (authors) 9 refs.

Determination of hourly contract heat and water flow and demand of the tariffs; Tuntinen tilaustehon ja -vesivirran maeaeritys ja tariffien vaatimukset

Energy Technology Data Exchange (ETDEWEB)

Hippinen, I.; Pirhonen, J.; Ahtila, P. [Helsinki University of Technology, Otaniemi (Finland); Maekelae, V.M. [Komartek Oy, Lappeenranta (Finland)

2000-07-01

This is the final report of the research project 'Determination of hourly contract heat and water flow and demand of the tariffs', which was carried out by the Helsinki University of Technology and Komartek Oy. The report consists of two parts. Part A presents the study of the Helsinki University of Technology, in which the consumption of domestic hot water in different size houses were clarified. Part B presents the tariff calculations carried out by Komartek Oy. In the part of the Helsinki University of Technology, the consumption of hot household water has been measured in different sized houses in order to determine their real demand of district heat and heat exhanger capacity. Including earlier measurements, measurements were carried out in 35 buildings. The size of the houses varied from a two-family house to a house of 204 flats. The domestic hot water flows and water temperatures to and from the heat exchanger were measured continuously during periods of a day and a week. To find out the congruence between reality and the dimensioning standards, the measurement results have been compared with the current dimensioning standards. It became evident in the study, that the current dimensioning standards are considerably oversized. Measured maximum heat consumptions were in general less than half of the dimensioned maximums. Operation times for the maximum loads were very short timed, ranging from some tens of seconds to a couple of minutes. The maximum peak loads were either in the mornings or in the evenings. However, no special week-days with clear maximum loads were found during week measurements. In second part was studied how the domestic hot water consumption will influence on the incomes of a DH company and payments of different kinds of customers. Domestic hot water was calculated as a one hour maximum. It was found out that there were outstanding differences in payments of different sizes of customers between different tariffs when the total

Optimal supply and demand investments in municipal energy systems

International Nuclear Information System (INIS)

Rolfsman, Bjoern

2004-01-01

In many municipalities, there are district heating networks, which are quite commonly supplied by combined heat and power plants (CHP). A district heating network contains buildings of different types. In this paper, one such municipal energy system is analysed. In order to provide space heating and domestic hot water, investments could be made on the supply side in power plants, or on the demand side in the buildings, for example in the form of extra wall insulation. The electricity from the CHP plants is supplied to the municipality but can also be sold to the electricity market, and electricity can, of course, also be bought from the market. The variation in price on the spot market over any given day is significant. The need for district heat in the building stock also varies, for example due to climatic conditions. The energy system in the case study is analysed with a mixed integer linear programming model. The model has 3 h time steps in order to reflect diurnal variations, and an entire year is analysed. A case study is presented for the city of Linkoeping in Sweden. On the demand side, the options are: extra wall insulation, extra attic insulation and better types of windows. The building stock is divided into nine categories

Measure Guideline: Combined Space and Water Heating Installation and Optimization

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [NorthernSTAR Building America Partnership, St. Paul, MN (United States); Bohac, D. [NorthernSTAR Building America Partnership, St. Paul, MN (United States); Huelman, P. [NorthernSTAR Building America Partnership, St. Paul, MN (United States)

2017-03-01

Combined space and water heater (combi or combo) systems are defined by their dual functionality. Combi systems provide both space heating and water heating capabilities with a single heat source. This guideline will focus on the installation and operation of residential systems with forced air heating and domestic hot water (DHW) functionality. Past NorthernSTAR research has used a combi system to replace a natural gas forced air distribution system furnace and tank type water heater (Schoenbauer et al. 2012; Schoenbauer, Bohac, and McAlpine 2014). The combi systems consisted of a water heater or boiler heating plant teamed with a hydronic air handler that included an air handler, water coil, and water pump to circulate water between the heating plant and coil. The combi water heater or boiler had a separate circuit for DHW. Past projects focused on laboratory testing, field characterization, and control optimization of combi systems. Laboratory testing was done to fully characterize and test combi system components; field testing was completed to characterize the installed performance of combi systems; and control methodologies were analyzed to understand the potential of controls to simplify installation and design and to improve system efficiency and occupant comfort. This past work was relied upon on to create this measure guideline.

Measure Guideline: Combined Space and Water Heating Installation and Optimization

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Bohac, D. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Huelman, P. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership

2017-03-03

Combined space and water heater (combi or combo) systems are defined by their dual functionality. Combi systems provide both space heating and water heating capabilities with a single heat source. This guideline will focus on the installation and operation of residential systems with forced air heating and domestic hot water (DHW) functionality. Past NorthernSTAR research has used a combi system to replace a natural gas forced air distribution system furnace and tank type water heater (Schoenbauer et al. 2012; Schoenbauer, Bohac, and McAlpine 2014). The combi systems consisted of a water heater or boiler heating plant teamed with a hydronic air handler that included an air handler, water coil, and water pump to circulate water between the heating plant and coil. The combi water heater or boiler had a separate circuit for DHW. Past projects focused on laboratory testing, field characterization, and control optimization of combi systems. Laboratory testing was done to fully characterize and test combi system components; field testing was completed to characterize the installed performance of combi systems; and control methodologies were analyzed to understand the potential of controls to simplify installation and design and to improve system efficiency and occupant comfort. This past work was relied upon on to create this measure guideline.

Analysis on exergy consumption patterns for space heating in Slovenian buildings

International Nuclear Information System (INIS)

Dovjak, Mateja; Shukuya, Masanori; Olesen, Bjarne W.; Krainer, Ales

2010-01-01

Problem of high energy use for heating in Slovenian buildings is analyzed with exergy and energy analysis. Results of both are compared and discussed. Three cases of exterior building walls are located in three climatic zones in winter conditions. Results of energy analyses show that the highest heating energy demand appears in the case with less thermal insulation, especially in colder climate. If the comparison is made only on the energy supply and exergy supply, the results of exergy analysis are the same as those of energy analysis. The main difference appears, if the whole chain of supply and demand is taken into consideration. Exergy calculations enable us to analyze how much exergy is consumed in which part, from boiler to building envelope. They also reveal how much energy is supplied for the purpose of heating. Results show that insulation has much bigger effect than effect of boiler efficiency. However, the most effective solution is to improve building envelope together with boiler efficiency. Better thermal insulation also makes an important contribution to the improvement of thermal comfort conditions. It causes higher surface temperatures resulting in a larger warm radiant exergy emission rate and consequently better thermal comfort.

Performance predictions and measurements for space-power-system heat pipes

International Nuclear Information System (INIS)

Prenger, F.C. Jr.

1981-01-01

High temperature liquid metal heat pipes designed for space power systems have been analyzed and tested. Three wick designs are discussed and a design rationale for the heat pipe is provided. Test results on a molybdenum, annular wick heat pipe are presented. Performance limitations due to boiling and capillary limits are presented. There is evidence that the vapor flow in the adiabatic section is turbulent and that the transition Reynolds number is 4000

The Swiss heating reactor (SHR) for district heating of small communities

International Nuclear Information System (INIS)

Burgsmueller, P.; Jacobi, A.Jr.; Jaeger, J.F.; Klaentschi, M.J.; Seifritz, W.; Vuillemier, F.; Wegmann, F.

1987-01-01

With fossil fuel running out in a foreseeable future, it is essential to develop substitution strategies. Some 40-50 % of the heat demand in industrial countries is below 120 degrees C, for space heating and warm water production, causing a corresponding fraction of air pollution by SO 2 and to a lesser extent NO x if fossil fuels are used. Yet, contemporary LWR technology makes it feasible to supply a district heating network without basically new reactor development. Units in the power range 10-50 MW are most suitable for Switzerland, both in respect of network size and of the democratic decision making structure. A small BWR for heating purpose is being developed by parts of the Swiss Industry and the Swiss Federal Institute for Reactor Research (EIR). The economic target of 100-120 SFr/MWh heat at the consumer's seems achievable. (author)

Performance of a Solar Heating System with Photovoltaic Thermal Hybrid Collectors and Heat Pump

DEFF Research Database (Denmark)

Dannemand, Mark; Furbo, Simon; Perers, Bengt

2017-01-01

. When the solar collectors are unable to supply the heat demand an auxiliary heat source is used. Heat pumps can generate this heat. Liquid/water heat pumps have better performance than air/water heat pumps in cold climates but requires installation of a tubing system for the cold side of the heat pump....... The tubes are typically placed in the ground, requires a significant land area and increase the installation cost. A new system design of a solar heating system with two storage tanks and a liquid/water heat pump is presented. The system consists of PVT collectors that generate both heat and electricity......The energy consumption in buildings accounts for a large part of the World’s CO2 emissions. Much energy is used for appliances, domestic hot water preparation and space heating. In solar heating systems, heat is captured by solar collectors when the sun is shining and used for heating purposes...

[Optimization of urban green space spatial arrangement based on supply-demand analysis: a case study in Nanjing City, China].

Science.gov (United States)

Gui, Kun-Peng; Xu, Jian-Gang; Zhang, Xiang

2013-05-01

Urban green space has the functions of ecological and social services, and the two services levels are decided by the supply-demand relationship. However, the supply-demand of green space not only involves in quantity, but also refers to spatial distribution. Therefore, only greening indicators can not wholly reflect the true levels of green space services. Based on the supply-demand analysis and supported by the ArcGIS, this paper examined the ecological and social services levels of the urban green spaces in Nanjing City by using the evenness indicator and the rate the people could enjoy the public green space in their accessible area. Accordingly, the ecological and social services levels of the green space in the City were investigated. The results showed that in the east of Nanjing City, green spaces were rich, but high accessible ones were lack, which resulted in a moderate social service level. In the center of the City, green spaces were lack and distributed unevenly, resulting in the low levels of ecological and social services. In Hexi area, due to the shortage in ecological green space and its uneven distribution, the green spaces had a high level social service but a low level ecological service. In the southern and northern areas of the City, green spaces were in deficiency, uneven distribution, and lack in high accessible.

A model predictive control strategy for the space heating of a smart building including cogeneration of a fuel cell-electrolyzer system

DEFF Research Database (Denmark)

Sossan, Fabrizio; Bindner, Henrik W.; Madsen, Henrik

2014-01-01

The objective of this paper is to analyze the value of energy replacement in the context of demand response. Energy replacement is dened as the possibility of the consumer to choose the most convenient source for providing space heating to a smart building according to a dynamic electricity price....... In the proposed setup, heat is provided by conventional electric radiators and a combined heat and power generation system, composed by a fuel cell and an electrolyzer. The energy replacement strategy is formulated using model predictive control and mathematical models of the components involved. Simulations show...... that the predictive energy replacement strategy reduces the operating costs of the system and is able to provide a larger amount of regulating power to the grid. In the paper, we also develop a novel dynamic model of a PEM fuel cell suitable for micro-grid applications. The model is realized applying a grey...

Heat-electricity convertion systems for a Brazilian space micro nuclear reactor

Energy Technology Data Exchange (ETDEWEB)

Guimaraes, Lamartine N.F.; Marcelino, Natalia B.; Placco, Guilherme M.; Nascimento, Jamil A.; Borges, Eduardo M., E-mail: guimarae@ieav.cta.br, E-mail: lamartine.guimaraes@pq.cnpq.br, E-mail: jamil@ieav.cta.br, E-mail: jalnsgf@outlook.com, E-mail: borges.em@hotmail.com, E-mail: ecorborges@hotmail.com, E-mail: ivayolini@gmail.com, E-mail: guilherme_placco@ig.com.br [Instituto de Estudos Avancados (IEAv/DCTA), Sao Jose dos Campos, SP (Brazil); Barrios Junior, Ary Garcia, E-mail: arygarcia89@yahoo.com [Faculdade de Tecnologia Sao Francisco (FATESF), Jacarei, SP (Brazil)

2013-07-01

This contribution will discuss the evolution work in the development of thermal cycles to allow the development of heat-electricity conversion for the Brazilian space micro nuclear Reactor. Namely, innovative core and nuclear fuel elements, Brayton cycle, Stirling engine, heat pipes, passive multi-fluid turbine, among others. This work is basically to set up the experimental labs that will allow the specification and design of the space equipment. Also, some discussion of the cost so far, and possible other applications will be presented. (author)

Heat-electricity convertion systems for a Brazilian space micro nuclear reactor

International Nuclear Information System (INIS)

Guimaraes, Lamartine N.F.; Marcelino, Natalia B.; Placco, Guilherme M.; Nascimento, Jamil A.; Borges, Eduardo M.; Barrios Junior, Ary Garcia

2013-01-01

This contribution will discuss the evolution work in the development of thermal cycles to allow the development of heat-electricity conversion for the Brazilian space micro nuclear Reactor. Namely, innovative core and nuclear fuel elements, Brayton cycle, Stirling engine, heat pipes, passive multi-fluid turbine, among others. This work is basically to set up the experimental labs that will allow the specification and design of the space equipment. Also, some discussion of the cost so far, and possible other applications will be presented. (author)

Space nuclear power and man's extraterrestrial civilization

International Nuclear Information System (INIS)

Angelo, J.J.; Buden, D.

1983-01-01

This paper examines leading space nuclear power technology candidates. Particular emphasis is given the heat-pipe reactor technology currently under development at the Los Alamos National Laboratory. This program is aimed at developing a 10-100 kWe, 7-year lifetime space nuclear power plant. As the demand for space-based power reaches megawatt levels, other nuclear reactor designs including: solid core, fluidized bed, and gaseous core, are considered

District heating

International Nuclear Information System (INIS)

Hansen, L.

1993-01-01

The environmental risks and uncertainties of a high-energy future are disturbing and give rise to several reservations concerning the use of fossil fuels. A number of technologies will help to reduce atmospheric pollution. In Denmark special importance is attached to the following: Energy conservation. Efficient energy conversion. Renewable energy sources. District heating, combined production of heat and power. Many agree that district heating (DH), produced by the traditional heat-only plant, and combined heat and power (CHP) have enormous potential when considering thermal efficiency and lowered environmental impacts: The basic technology of each is proven, it would be relatively simple to satisfy a substantial part of the energy demand, and their high efficiencies mean reduced pollution including greenhouse gas emissions. This is especially important in high population density areas - the obviously preferred sites for such energy generation. Compared with individual heating DH can provide a community with an operationally efficient and most often also an economically competitive heat supply. This is particularly true under the circumstances where the DH system is supplied from CHP plants. Their use results in very substantial improvements in overall efficiency. Further environmental improvements arise from the reduced air pollution obtainable in reasonably large CHP plants equipped with flue gas cleaning to remove particles, sulphur dioxide, and nitrogen acids. As a consequence of these considerations, DH plays an important role in fulfilling the space and water heating demand in many countries. This is especially the case in Denmark where this technology is utilised to a very great extent. Indeed, DH is one of the reasons why Denmark has relatively good air quality in the cities. (au)

Solar Heating System with Building-Integrated Heat Storage

DEFF Research Database (Denmark)

Heller, Alfred

1996-01-01

Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating, and due to storage. Heat demand is reduced due to direct solar heating, due to storage and due to lower heat losses through the ground. In theory, by running the system flow backwards through the sand storage, active heating...... can be achieved.The objective of the report is to present results from measured system evaluation andcalculations and to give guidelines for the design of such solar heating systems with building integrated sand storage. The report is aimed to non-technicians. In another report R-006 the main results...

Potential application of glazed transpired collectors to space heating in cold climates

International Nuclear Information System (INIS)

Gao, Lixin; Bai, Hua; Mao, Shufeng

2014-01-01

Highlights: • A mathematical model for glazed transpired collectors (GTC) is developed. • Glazing results in optical loss, but it decreases convective heat loss effectively. • Thermal performance of GTC shows considerable improvement on flat-plate collectors. • GTC using recirculated air is applicable to space heating in cold climates. - Abstract: Although unglazed transpired collectors (UTC) succeed in industrial ventilation applications, solar fraction is very low when they are used in space heating in cold climates due to the lower exit air temperature. Considering the potential for glazed transpired collectors (GTC) using recirculated air for space heating applications in cold climates, a mathematical model is developed for predicting the thermal performance of GTC. Simulation results show that although glazing results in optical loss, it could decrease convective heat loss resulted from high crosswind velocities effectively. For a solar radiation of 400 W/m 2 , an ambient temperature of −10 °C, and a suction velocity of 0.01 m/s, the exit air temperature of GTC is higher than that of UTC for crosswind velocities exceeding 3.0 m/s. By comparison with a conventional flat-plate solar air collector operating under the same conditions, the thermal performance of GTC shows a significant improvement. For a five-storey hotel building located in the severe cold climate zone of China, case study shows that the annual solar fraction of the GTC-based solar air heating system is about 20%, which is two times higher than that of the flat-plate collector-based system and nearly nine times higher than that of the UTC-based system respectively. Hence, an enormous amount of energy will be saved with the application of GTC to space heating in cold climates

Impacts of the 2011 Tohoku earthquake on electricity demand in Japan. State space approach

International Nuclear Information System (INIS)

Honjo, Keita; Ashina, Shuichi

2017-01-01

Some papers report that consumers' electricity saving behavior (Setsuden) after the 2011 Tohoku Earthquake resulted in the reduction of the domestic electricity demand. However, time variation of the electricity saving effect (ESE) has not yet been sufficiently investigated. In this study, we develop a state space model of monthly electricity demand using long-term data, and estimate time variation of the ESE. We also estimate time variation of CO_2 emissions caused by Setsuden. Our result clearly indicates that Setsuden after the earthquake was not temporary but became established as a habit. Between March 2011 and October 2015, the ESE on power demand ranged from 2.9% to 6.9%, and the ESE on light demand ranged from 2.6% to 9.0%. The ESE on the total electricity demand was 3.2%-7.5%. Setsuden also contributed to the reduction of CO_2 emissions, but it could not offset the emissions increase caused by the shutdown of nuclear power plants. (author)

Estimation of European Union residential sector space cooling potential

International Nuclear Information System (INIS)

Jakubcionis, Mindaugas; Carlsson, Johan

2017-01-01

Data on European residential space cooling demands are scarce and often of poor quality. This can be concluded from a review of the Comprehensive Assessments on the energy efficiency potential in the heating and cooling sector performed by European Union Member States under Art. 14 of the Energy Efficiency Directive. This article estimates the potential space cooling demands in the residential sector of the EU and the resulting impact on electricity generation and supply systems using the United States as a proxy. A georeferenced approach was used to establish the potential residential space cooling demand in NUTS-3 regions of EU. The total potential space cooling demand of the EU was estimated to be 292 TW h for the residential sector in an average year. The additional electrical capacity needed was estimated to 79 GW. With proper energy system development strategies, e.g. matching capacity of solar PV with cooling demand, or introduction of district cooling, the stresses on electricity system from increasing cooling demand can be mitigated. The estimated potential of space cooling demand, identified in this paper for all EU Members States, could be used while preparing the next iteration of EU MS Comprehensive Assessments or other energy related studies. - Highlights: • An estimation of EU space cooling demand potential in residential sector is presented. • An estimate of space cooling demand potential is based on using USA data as a proxy. • Significant cooling demand increase can be expected. • Cooling demand increase would lead to increased stress in energy supply systems. • Proper policies and strategies might measurably decrease the impact on energy systems.

Research-grade CMOS image sensors for demanding space applications

Science.gov (United States)

Saint-Pé, Olivier; Tulet, Michel; Davancens, Robert; Larnaudie, Franck; Magnan, Pierre; Corbière, Franck; Martin-Gonthier, Philippe; Belliot, Pierre

2017-11-01

Imaging detectors are key elements for optical instruments and sensors on board space missions dedicated to Earth observation (high resolution imaging, atmosphere spectroscopy...), Solar System exploration (micro cameras, guidance for autonomous vehicle...) and Universe observation (space telescope focal planes, guiding sensors...). This market has been dominated by CCD technology for long. Since the mid- 90s, CMOS Image Sensors (CIS) have been competing with CCDs for more and more consumer domains (webcams, cell phones, digital cameras...). Featuring significant advantages over CCD sensors for space applications (lower power consumption, smaller system size, better radiations behaviour...), CMOS technology is also expanding in this field, justifying specific R&D and development programs funded by national and European space agencies (mainly CNES, DGA, and ESA). All along the 90s and thanks to their increasingly improving performances, CIS have started to be successfully used for more and more demanding applications, from vision and control functions requiring low-level performances to guidance applications requiring medium-level performances. Recent technology improvements have made possible the manufacturing of research-grade CIS that are able to compete with CCDs in the high-performances arena. After an introduction outlining the growing interest of optical instruments designers for CMOS image sensors, this talk will present the existing and foreseen ways to reach high-level electro-optics performances for CIS. The developments of CIS prototypes built using an imaging CMOS process and of devices based on improved designs will be presented.

Energy and exergy analysis of low temperature district heating network

International Nuclear Information System (INIS)

Li, Hongwei; Svendsen, Svend

2012-01-01

Low temperature district heating with reduced network supply and return temperature provides better match of the low quality building heating demand and the low quality heating supply from waste heat or renewable energy. In this paper, a hypothetical low temperature district heating network is designed to supply heating for 30 low energy detached residential houses. The network operational supply/return temperature is set as 55 °C/25 °C, which is in line with a pilot project carried out in Denmark. Two types of in-house substations are analyzed to supply the consumer domestic hot water demand. The space heating demand is supplied through floor heating in the bathroom and low temperature radiators in the rest of rooms. The network thermal and hydraulic conditions are simulated under steady state. A district heating network design and simulation code is developed to incorporate the network optimization procedure and the network simultaneous factor. Through the simulation, the overall system energy and exergy efficiencies are calculated and the exergy losses for the major district heating system components are identified. Based on the results, suggestions are given to further reduce the system energy/exergy losses and increase the quality match between the consumer heating demand and the district heating supply. -- Highlights: ► Exergy and energy analysis for low and medium temperature district heating systems. ► Different district heating network dimensioning methods are analyzed. ► Major exergy losses are identified in the district heating network and the in-house substations. ► Advantages to apply low temperature district heating are highlighted through exergy analysis. ► The influence of thermal by-pass on system exergy/energy performance is analyzed.

A heat receiver design for solar dynamic space power systems

Science.gov (United States)

Baker, Karl W.; Dustin, Miles O.; Crane, Roger

1990-01-01

An advanced heat pipe receiver designed for a solar dynamic space power system is described. The power system consists of a solar concentrator, solar heat receiver, Stirling heat engine, linear alternator and waste heat radiator. The solar concentrator focuses the sun's energy into a heat receiver. The engine and alternator convert a portion of this energy to electric power and the remaining heat is rejected by a waste heat radiator. Primary liquid metal heat pipes transport heat energy to the Stirling engine. Thermal energy storage allows this power system to operate during the shade portion of an orbit. Lithium fluoride/calcium fluoride eutectic is the thermal energy storage material. Thermal energy storage canisters are attached to the midsection of each heat pipe. The primary heat pipes pass through a secondary vapor cavity heat pipe near the engine and receiver interface. The secondary vapor cavity heat pipe serves three important functions. First, it smooths out hot spots in the solar cavity and provides even distribution of heat to the engine. Second, the event of a heat pipe failure, the secondary heat pipe cavity can efficiently transfer heat from other operating primary heat pipes to the engine heat exchanger of the defunct heat pipe. Third, the secondary heat pipe vapor cavity reduces temperature drops caused by heat flow into the engine. This unique design provides a high level of reliability and performance.

Energetical and ecological assessment of solar- and heat pump technologies for hot water preparation and space heating in Austria

International Nuclear Information System (INIS)

Faninger, G.

1991-11-01

Solar and heat pump systems have been proved in many applications on the market. To achieve an efficient energy output it is necessary to consider the special conditions of these technologies. The energetical and ecological criteria of solar and heat pump systems for hot water preparation and space heating are analysed on the basis of experimental data. (author)

Solar Space and Water Heating for School -- Dallas, Texas

Science.gov (United States)

1982-01-01

90 page report gives overview of retrofitted solar space-heating and hot-water system installation for 61-year-old high school. Description, specifications, modifications, plan drawings for roof, three floors, basement, correspondence, and documents are part of report.

Potential of Demand Side Management to Reduce Carbon Dioxide Emissions Associated with the Operation of Heat Pumps

Directory of Open Access Journals (Sweden)

Samuel J. G. Cooper

2013-06-01

Full Text Available This work considers the potential reduction in the carbon dioxide emissions associated with the operation of Air Source Heat Pump which could be achieved by using demand side management. In order to achieve significant reductions in carbon dioxide emissions, it is widely envisioned that electrification of the heating sector will need to be combined with decarbonisation of the electrical supply. By influencing the times at when electric heat pumps operate such that they coincide more with electricity generation which has a low marginal carbon emissions factor, it has been suggested that these emissions could be reduced further. In order to investigate this possibility, models of the UK electrical grid based on scenarios for 2020 to 2050 have been combined with a dynamic model of an air source heat pump unit and thermal models of a population of dwellings. The performance and carbon dioxide emissions associated with the heat pumps are compared both with and without demand side management interventions intended to give preference to operation when the marginal emissions factor of the electricity being generated is low. It is found that these interventions are unlikely to be effective at achieving further reductions in emissions. A reduction of around 3% was observed in scenarios based around 2035 but in other scenarios the reduction was insignificant. In the scenarios with high wind generation (2050, the DSM scheme considered here tends to improve thermal comfort (with minimal increases in emissions rather than achieving a decrease in emissions. The reasons for this are discussed and further recommendations are made.

Climate change and energy demand

International Nuclear Information System (INIS)

Hengeveld, H.G.

1991-01-01

Climate and weather events affect energy demand in most economic sectors. Linear relationships exist between consumption and heating degree days, and peak electricity demand increases significantly during heat waves. The relative magnitudes of demand changes for a two times carbon dioxide concentration scenario are tabulated, illustrating heating degree days and cooling degree days for 5 Prairie locations. Irrigation, water management, crop seeding and harvesting and weed control are examples of climate-dependent agricultural activities involving significant energy use. The variability of summer season liquid fuel use in the agricultural sector in the Prairie provinces from 1984-1989 shows a relationship between agricultural energy use and regional climate fluctuations. 4 refs., 2 figs., 1 tab

The Distributed Geothermal Market Demand Model (dGeo): Documentation

Energy Technology Data Exchange (ETDEWEB)

McCabe, Kevin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Mooney, Meghan E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sigrin, Benjamin O [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gleason, Michael [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Liu, Xiaobing [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-11-06

The National Renewable Energy Laboratory (NREL) developed the Distributed Geothermal Market Demand Model (dGeo) as a tool to explore the potential role of geothermal distributed energy resources (DERs) in meeting thermal energy demands in the United States. The dGeo model simulates the potential for deployment of geothermal DERs in the residential and commercial sectors of the continental United States for two specific technologies: ground-source heat pumps (GHP) and geothermal direct use (DU) for district heating. To quantify the opportunity space for these technologies, dGeo leverages a highly resolved geospatial database and robust bottom-up, agent-based modeling framework. This design is consistent with others in the family of Distributed Generation Market Demand models (dGen; Sigrin et al. 2016), including the Distributed Solar Market Demand (dSolar) and Distributed Wind Market Demand (dWind) models. dGeo is intended to serve as a long-term scenario-modeling tool. It has the capability to simulate the technical potential, economic potential, market potential, and technology deployment of GHP and DU through the year 2050 under a variety of user-defined input scenarios. Through these capabilities, dGeo can provide substantial analytical value to various stakeholders interested in exploring the effects of various techno-economic, macroeconomic, financial, and policy factors related to the opportunity for GHP and DU in the United States. This report documents the dGeo modeling design, methodology, assumptions, and capabilities.

Combined Space and Water Heating: Next Steps to Improved Performance

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Bohac, D. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Huelman, P. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States)

2016-07-13

A combined space- and water-heating (combi) system uses a high-efficiency direct-vent burner that eliminates safety issues associated with natural draft appliances. Past research with these systems shows that using condensing water heaters or boilers with hydronic air handling units can provide both space and water heating with efficiencies of 90% or higher. Improved controls have the potential to reduce complexity and improve upon the measured performance. This project demonstrates that controls can significantly benefit these first-generation systems. Laboratory tests and daily load/performance models showed that the set point temperature reset control produced a 2.1%-4.3% (20-40 therms/year) savings for storage and hybrid water heater combi systems operated in moderate-load homes.

Industrial excess heat for district heating in Denmark

International Nuclear Information System (INIS)

Bühler, Fabian; Petrović, Stefan; Karlsson, Kenneth; Elmegaard, Brian

2017-01-01

Highlights: •Method for utilisation potential of industrial excess heat for district heating. •Industrial excess heat from thermal processes is quantified at single production units. •Linking of industrial excess heat sources and district heating demands done in GIS. •Excess heat recovery using direct heat transfer and heat pumps. •5.1% of the Danish district heating demand could be supplied by industrial excess heat. -- Abstract: Excess heat is available from various sources and its utilisation could reduce the primary energy use. The accessibility of this heat is however dependent amongst others on the source and sink temperature, amount and potential users in its vicinity. In this work a new method is developed which analyses excess heat sources from the industrial sector and how they could be used for district heating. This method first allocates excess heat to single production units by introducing and validating a new approach. Spatial analysis of the heat sources and consumers are then performed to evaluate the potential for using them for district heating. In this way the theoretical potential of using the excess heat for covering the heating demand of buildings is determined. Through the use of industry specific temperature profiles the heat usable directly or via heat pumps is further found. A sensitivity analysis investigates the impact of future energy efficiency measures in the industry, buildings and the district heating grid on the national potential. The results show that for the case study of Denmark, 1.36 TWh of district heat could be provided annually with industrial excess heat from thermal processes which equals 5.1% of the current demand. More than half of this heat was found to be usable directly, without the need for a heat pump.

Investigation on Solar Heating System with Building-Integrated Heat Storage

DEFF Research Database (Denmark)

Heller, Alfred

1996-01-01

Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating and due to storage. The storage affects the heat demand passively due to higher temperatures. Hence heat loss is reduced and passive heating is optioned. In theory, by running the system flow backwards, active heating can...... solar collector area of the system, was achieved. Active heating from the sand storage was not observed. The pay-back time for the system can be estimated to be similar to solar heated domestic hot water systems in general. A number of minor improvements on the system could be pointed out....

A solar combi-system based on a heat exchanger between the collector loop and space-heating loop (IEA task 26 generic system 2). A report of IEA SHC - task 26 solar combisystems

International Nuclear Information System (INIS)

Ellehauge, K.

2002-12-01

The most common Danish solar combi-system is theoretically investigated in the report. The principle in the system is that in a normal solar hot water system a heat exchanger is added to deliver solar energy from the collector loop directly to the space heating loop. In this way solar energy for space heating is not stored which is expected to decrease the performance. On the other hand the system is relatively inexpensive, which can compensate for a reduced performance. A TRNSYS model of the system is developed and sensitivity analyses of parameters are performed by simulation. The analyses show no major improvements of the system. Special emphasis has been put on investigating the control strategy and to investigate if the thermal mass of radiators of floor could act as buffer for the solar energy delivered to space heating and in this way improve the performance. The analyses show that this is possible and has advantages at larger collector areas. However the improvements are not as large as expected. An economic optimisation gives and optimum solar collector area of approximately 10 m 2 . However the optimum curve is quite flat for areas above 7 m 2 , and collector areas up to 15 m 2 are also feasible. The calculated performacnes have been the basis for comparisons with the other systems modelled in the task 26. The comparison shows that the performance is not among the best, but however probably not as bad as expected. Furthermore the inexpensive design compensates to some extent for the lower performance. Furthermore the material use of the system and the energy used to produce the materials has been estimated. The energy demand is in a range that gives energy pay back times of 1.9-2.5 years. (au)

Effect of the inter-block spacing on the thermal performance of a PCM based heat sink

Energy Technology Data Exchange (ETDEWEB)

Faraji, M.; El Qarnia, H. [Cadi Ayyad Univ., Marrakech (Morocco). Faculte des sciences Semlalia, Dept. de physique, Laboratoire de mecanique des fluides et d' energetique; El Khadir, L. [Cadi Ayyad Univ., Marrakech (Morocco). Faculte des sciences Semlalia, Dept. de physique, Laboratoire d' tomatique de l' Environnement et Procedes de Transferts

2010-07-01

Advanced electronic devices require efficient thermal control systems. Heat transfer analysis of such systems is challenging because of constraints regarding space limitations, power consumption and noise level. This study considered the problem of melting and natural convection in a rectangular enclosure heated with 3 heat sources with a constant and uniform volumetric heat generation. The heat sources were protruding and mounted on a vertical conducting plate. Conjugate conduction in a plate and heat sources coupled with natural convection and melting process were examined in an effort to determine the effects of the inter-blocks spacing ratio on the thermal performance of the cooling PCM-heat sink. The percentage contribution of substrate heat conduction on the total removed heat from heat sources was also investigated. Correlations were derived for the non- dimensional secured working time and the corresponding melt fraction. In order to investigate the thermal behaviour of the proposed heat sink, a mathematical model was developed based on the mass, momentum and energy conservation equations. The results revealed that for lower inter-blocks spacing, the dimensionless secured working time needed by the chips to reach the critical temperature was maximized. The highest inter-blocks spacing ratio provoked a sudden rise in chip temperatures and thus reduced the dimensionless secured working time. It was concluded that this approach can be used in the design of PCM-based cooling systems. 9 refs., 2 tabs., 4 figs.

Laboratory Evaluation of Gas-Fired Tankless and Storage Water Heater Approaches to Combination Water and Space Heating

Energy Technology Data Exchange (ETDEWEB)

Kingston, T. [Gas Technology Inst., Des Plaines, IL (United States); Scott, S. [Gas Technology Inst., Des Plaines, IL (United States)

2013-03-01

Homebuilders are exploring more cost-effective combined space and water heating systems (combo systems) with major water heater manufacturers that are offering pre-engineered forced air space heating combo systems. In this project, unlike standardized tests, laboratory tests were conducted that subjected condensing tankless and storage water heater based combo systems to realistic, coincidental space and domestic hot water loads and found that the tankless combo system maintained more stable DHW and space heating temperatures than the storage combo system, among other key findings.

Economic Evaluation of a Solar Charged Thermal Energy Store for Space Heating

OpenAIRE

Melo, Manuel

2013-01-01

A thermal energy store corrects the misalignment of heating demand in the winter relative to solar thermal energy gathered in the summer. This thesis reviews the viability of a solar charged hot water tank thermal energy store for a school at latitude 56.25N, longitude -120.85W

Heat Roadmap Europe: Identifying strategic heat synergy regions

International Nuclear Information System (INIS)

Persson, U.; Möller, B.; Werner, S.

2014-01-01

This study presents a methodology to assess annual excess heat volumes from fuel combustion activities in energy and industry sector facilities based on carbon dioxide emission data. The aim is to determine regional balances of excess heat relative heat demands for all third level administrative regions in the European Union (EU) and to identify strategic regions suitable for large-scale implementation of district heating. The approach is motivated since the efficiency of current supply structures to meet building heat demands, mainly characterised by direct use of primary energy sources, is low and improvable. District heating is conceived as an urban supply side energy efficiency measure employable to enhance energy system efficiency by increased excess heat recoveries; hereby reducing primary energy demands by fuel substitution. However, the importance of heat has long been underestimated in EU decarbonisation strategies and local heat synergies have often been overlooked in energy models used for such scenarios. Study results indicate that 46% of all excess heat in EU27, corresponding to 31% of total building heat demands, is located within identified strategic regions. Still, a realisation of these rich opportunities will require higher recognition of the heat sector in future EU energy policy. - Highlights: • EU27 energy and industry sector heat recycling resources are mapped and quantified. • Target regions for large-scale implementation of district heating are identified. • 46% of total EU27 excess heat volume is seized in 63 strategic heat synergy regions. • Large urban zones have lead roles to play in transition to sustainability in Europe. • Higher recognition of heat sector is needed in future EU energy policy for realisation

Model-based energy performance assessment of the world largest underground seasonal thermal energy storage in a pilot district heating system in Chifeng City

NARCIS (Netherlands)

Xu, L.; Torrens Galdiz, J.I.; Guo, F.; Yang, X.; Hensen, J.L.M.

2017-01-01

District heating systems play an important role in supporting energy transition by using and storing energy delivered by renewable and other low-grade energy sources such as industrial waste heat. However, this low-grade heat is not always able to satisfy the heating demand, including space heating

Self-rewetting carbon nanofluid as working fluid for space and terrestrial heat pipes

Science.gov (United States)

Di Paola, R.; Savino, R.; Mirabile Gattia, D.; Marazzi, R.; Vittori Antisari, M.

2011-11-01

Thermal management is very important in modern electronic systems. Recent researches have been dedicated to the study of the heat transfer performances of binary heat transfer fluids with peculiar surface tension properties and in particular to that of "self-rewetting fluids", i.e., liquids with a surface tension increasing with temperature and concentration. Since in the course of liquid/vapor-phase change, self-rewetting fluids behavior induces a rather strong liquid inflow (caused by both temperature and concentration gradients) from the cold region (where liquid condensates) to the hot evaporator region, this fluids have been proposed and investigated as new heat transfer fluids for advanced heat transfer devices, e.g., heat pipes or heat spreaders for terrestrial and space applications (Savino et al. in Space Technol 25(1):59-61, 2009). The present work is dedicated to the study of the thermophysical properties of a new class of heat transfer fluids based on water/alcohol solutions with suspended carbon nanostructures, in particular single-wall carbon nanohorns (SWNH), synthesized by a homemade apparatus with an AC arc discharge in open air (Mirabile Gattia et al. in Nanotechnology 18:255604, 2007). SWNHs are cone-shaped nanoparticles with diameters between 1 and 5 nm and lengths in the range of 20-100 nm. SWNHs could be found in the form of quite-spherical aggregates with diameters ranging from 20 to 100 nm. The paper also discusses the results of these investigations and laboratory characterization tests of different heat pipes, including reference ordinary heat pipes and innovative pipes filled with self-rewetting fluids and self-rewetting nanofluids. The potential interest of the proposed studies stems from the large number of possible industrial applications, including space technologies and terrestrial applications, such as cooling of electronic components.

Self-rewetting carbon nanofluid as working fluid for space and terrestrial heat pipes

International Nuclear Information System (INIS)

Di Paola, R.; Savino, R.; Mirabile Gattia, D.; Marazzi, R.; Vittori Antisari, M.

2011-01-01

Thermal management is very important in modern electronic systems. Recent researches have been dedicated to the study of the heat transfer performances of binary heat transfer fluids with peculiar surface tension properties and in particular to that of “self-rewetting fluids”, i.e., liquids with a surface tension increasing with temperature and concentration. Since in the course of liquid/vapor-phase change, self-rewetting fluids behavior induces a rather strong liquid inflow (caused by both temperature and concentration gradients) from the cold region (where liquid condensates) to the hot evaporator region, this fluids have been proposed and investigated as new heat transfer fluids for advanced heat transfer devices, e.g., heat pipes or heat spreaders for terrestrial and space applications (Savino et al. in Space Technol 25(1):59–61, 2009). The present work is dedicated to the study of the thermophysical properties of a new class of heat transfer fluids based on water/alcohol solutions with suspended carbon nanostructures, in particular single-wall carbon nanohorns (SWNH), synthesized by a homemade apparatus with an AC arc discharge in open air (Mirabile Gattia et al. in Nanotechnology 18:255604, 2007). SWNHs are cone-shaped nanoparticles with diameters between 1 and 5 nm and lengths in the range of 20–100 nm. SWNHs could be found in the form of quite-spherical aggregates with diameters ranging from 20 to 100 nm. The paper also discusses the results of these investigations and laboratory characterization tests of different heat pipes, including reference ordinary heat pipes and innovative pipes filled with self-rewetting fluids and self-rewetting nanofluids. The potential interest of the proposed studies stems from the large number of possible industrial applications, including space technologies and terrestrial applications, such as cooling of electronic components.

Demand control on room level of the supply air temperature in an air heating and ventilation system

DEFF Research Database (Denmark)

Polak, Joanna; Afshari, Alireza; Bergsøe, Niels Christian

2017-01-01

air heating and ventilation system in a high performance single family house using BSim simulation software. The provision of the desired thermal conditions in different rooms was examined. Results show that the new control strategy can facilitate maintaining of desired temperatures in various rooms......The aim of this study was to investigate a new strategy for control of supply air temperature in an integrated air heating and ventilation system. The new strategy enables demand control of supply air temperature in individual rooms. The study is based on detailed dynamic simulations of a combined....... Moreover, this control strategy enables controlled temperature differentiation between rooms within the house and therefore provides flexibility and better balance in heat delivery. Consequently, the thermal conditions in the building can be improved....

The impact of air-tightness in the retrofitting practice of low temperature heating

OpenAIRE

Wang, Qian; Holmberg, Sture

2014-01-01

In Sweden, the energy usage in existing residential buildings amounted to 147 TWh in 2012, equivalent to almost 40 % of the final overall national energy usage. Among all the end users in building service sectors, 60 % of the final energy in Sweden is used for space heating and domestic hot water (DHW) production in 2013. In order to reduce the supply temperature for space heating in existing buildings, combined approaches are favorably adopted: to reduce the net energy demand by air-tightnes...

Model for Determining Geographical Distribution of Heat Saving Potentials in Danish Building Stock

DEFF Research Database (Denmark)

Petrovic, Stefan; Karlsson, Kenneth Bernard

2014-01-01

Since the global oil crisis in the 1970s, Denmark has followed a path towards energy independency by continuously improving its energy efficiency and energy conservation. Energy efficiency was mainly tackled by introducing a high number of combined heat and power plants in the system, while energy...... conservation was predominantly approached by implementing heat saving measures. Today, with the goal of 100% renewable energy within the power and heat sector by the year 2035, reductions in energy demand for space heating and the preparation of domestic hot water remain at the top of the agenda in Denmark....... A highly detailed model for determining heat demand, possible heat savings and associated costs in the Danish building stock is presented. Both scheduled and energy-saving renovations until year 2030 have been analyzed. The highly detailed GIS-based heat atlas for Denmark is used as a container for storing...

Space shuttle/food system study. Volume 2, Appendix A: Active heating system-screening analysis. Appendix B: Reconstituted food heating techniques analysis

Science.gov (United States)

1974-01-01

Technical data are presented which were used to evaluate active heating methods to be incorporated into the space shuttle food system design, and also to evaluate the relative merits and penalties associated with various approaches to the heating of rehydrated food during space flight. Equipment heating candidates were subject to a preliminary screening performed by a selection rationale process which considered the following parameters; (1) gravitational effect; (2) safety; (3) operability; (4) system compatibility; (5) serviceability; (6) crew acceptability; (7) crew time; (8) development risk; and (9) operating cost. A hot air oven, electrically heated food tray, and microwave oven were selected for further consideration and analysis. Passive, semi-active, and active food preparation approaches were also studied in an effort to determine the optimum method for heating rehydrated food. Potential complexity, cost, vehicle impact penalties, and palatability were considered in the analysis. A summary of the study results is provided along with cost estimates for each of the potential sytems

Thin film heat flux sensor for Space Shuttle Main Engine turbine environment

Science.gov (United States)

Will, Herbert

1991-01-01

The Space Shuttle Main Engine (SSME) turbine environment stresses engine components to their design limits and beyond. The extremely high temperatures and rapid temperature cycling can easily cause parts to fail if they are not properly designed. Thin film heat flux sensors can provide heat loading information with almost no disturbance of gas flows or of the blade. These sensors can provide steady state and transient heat flux information. A thin film heat flux sensor is described which makes it easier to measure small temperature differences across very thin insulating layers.

Utilising heat from nuclear waste for space heating

International Nuclear Information System (INIS)

Deacon, D.

1982-01-01

A heating unit utilising the decay heat from irradiated material comprises a storage envelope for the material associated with a heat exchange system, means for producing a flow of air over the heat exchange system to extract heat from the material, an exhaust duct capable of discharging the heated air to the atmosphere, and means for selectively diverting at least some of the heated air to effect the required heating. With the flow of air over the heat exchange system taking place by a natural thermosyphon process the arrangement is self regulating and inherently reliable. (author)

Geothermal district heating system feasibility analysis, Thermopolis, Wyoming

Energy Technology Data Exchange (ETDEWEB)

Goering, S.W.; Garing, K.L.; Coury, G.; Mickley, M.C.

1982-04-26

The purpose of this study is to determine the technical and economic feasibility of constructing and operating a district heating system to serve the residential, commercial, and public sectors in Thermopolis. The project geothermal resource assessment, based on reviews of existing information and data, indicated that substantial hot water resources likely exist in the Rose Dome region 10 miles northeast of Thermopolis, and with quantities capable of supporting the proposed geothermal uses. Preliminary engineering designs were developed to serve the space heating and hot water heating demands for buildings in the Thermopolis-East Thermopolis town service area. The heating district design is based on indirect geothermal heat supply and includes production wells, transmission lines, heat exchanger units, and the closed loop distribution and collection system necessary to serve the individual customers. Three options are presented for disposal of the cooled waters-reinjection, river disposal, and agricultural reuse. The preliminary engineering effort indicates the proposed system is technically feasible. The design is sized to serve 1545 residences, 190 businesses, and 24 public buildings. The peak design meets a demand of 128.2 million Btu at production rates of 6400 gpm.

A Study of Thermal Performance of Contemporary Technology-Rich Educational Spaces

Directory of Open Access Journals (Sweden)

Sarah Elmasry

2013-08-01

Full Text Available One of the most dominant features of a classroom space is its high occupancy, which results in high internal heat gain (approximately 5 KW. Furthermore, installation of educational technologies, such as smart boards, projectors and computers in the spaces increases potential internal heat gain. Previous studies on office buildings indicate that with the introduction of IT equipment in spaces during the last decade, cooling load demands are increasing with an associated increase in summer electrical demand. Due to the fact that educational technologies in specific correspond to pedagogical practices within the space, a lot of variations due to occupancy patterns occur. Also, thermal loads caused by educational technologies are expected to be dependent on spatial configuration, for example, position with respect to the external walls, lighting equipment, mobility of devices. This study explores the thermal impact of educational technologies in 2 typical educational spaces in a facility of higher education; the classroom and the computer lab. The results indicate that a heat gain ranging between 0.06 and 0.095 KWh/m2 is generated in the rooms when educational technologies are in use. The second phase of this study is ongoing, and investigates thermal zones within the rooms due to distribution of educational technologies. Through simulation of thermal performance of the rooms, alternative room configurations are thus recommended in response to the observed thermal zones.

Model documentation report: Commercial Sector Demand Module of the National Energy Modeling System

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-01-01

This report documents the objectives, analytical approach and development of the National Energy Modeling System (NEMS) Commercial Sector Demand Module. The report catalogues and describes the model assumptions, computational methodology, parameter estimation techniques, model source code, and forecast results generated through the synthesis and scenario development based on these components. The NEMS Commercial Sector Demand Module is a simulation tool based upon economic and engineering relationships that models commercial sector energy demands at the nine Census Division level of detail for eleven distinct categories of commercial buildings. Commercial equipment selections are performed for the major fuels of electricity, natural gas, and distillate fuel, for the major services of space heating, space cooling, water heating, ventilation, cooking, refrigeration, and lighting. The algorithm also models demand for the minor fuels of residual oil, liquefied petroleum gas, steam coal, motor gasoline, and kerosene, the renewable fuel sources of wood and municipal solid waste, and the minor services of office equipment. Section 2 of this report discusses the purpose of the model, detailing its objectives, primary input and output quantities, and the relationship of the Commercial Module to the other modules of the NEMS system. Section 3 of the report describes the rationale behind the model design, providing insights into further assumptions utilized in the model development process to this point. Section 3 also reviews alternative commercial sector modeling methodologies drawn from existing literature, providing a comparison to the chosen approach. Section 4 details the model structure, using graphics and text to illustrate model flows and key computations.

District Heating Expansion Potential with Low-Temperature and End-Use Heat Savings

DEFF Research Database (Denmark)

Nielsen, Steffen; Grundahl, Lars

2018-01-01

District heating has the potential to play a key role in the transition towards a renewable energy system. However, the development towards reduced heat demands threatens the feasibility of district heating. Despite this challenge, opportunity exists in the form of fourth generation district...... heating, which operates at lower temperatures and enables better renewable integration. This article investigates this challenge by examining the district heating potential within three scenarios: The first is a reference scenario with current heat demand and temperatures, the second includes heat demand...... costs. The models are applied using an example case of The Northern Region of Denmark. The article concludes that the district heating potential is highest in the reference scenario. When heat savings are introduced, district heating expansions, in most cases, will not be feasible. Introducing low...

On-Demand Telemetry

Data.gov (United States)

National Aeronautics and Space Administration — AFRC has previously investigated the use of Network Based Telemetry. We will be building on that research to enable On-Demand Telemetry. On-Demand Telemetry is a way...

Utes for space heating and cooling in North Africa

International Nuclear Information System (INIS)

Nordell, B.; Grein, M. a.

2006-01-01

The North Africa climate is dry and warm with annual mean temperature from 15 degree centigrade to 25 degree centigrade, with a temperature difference of 20 degree centigrade between the coldest and warmest month. Heating is needed during the short winter and there is a large cooling demand during the long summer. Since the undisturbed ground temperature is equal to the annual mean air temperature, the ground is warmer than the air during the winter and colder than air during summer. This is what is required for the direct use of the ground for heating and cooling. In such systems, ground coupled heating and cooling systems, and also in storage systems, Underground Thermal Energy Storage (UTES), some kind of underground duct (PIPE) system is used to inject or extract heat from the ground. Thermal energy is then stored and recovered by heating and cooling of the ground, while the ducts are the heat exchangers with the system. The duct system could be placed horizontally or vertically (e.g. in boreholes) in the ground. In many cases heat pumps or cooling machines are included in the systems but in favourable cases, such as in the North African climate, the ground can be used directly for heating and cooling. then, only a circulation pump is used to pump water through the underground duct system with high efficiencies. Such systems can also be used for thermal energy storage, during shorter periods (diurnal) or even between the seasons. In September 2005 Sebha University and Luleu University of Technology started a Libyan Swedish collaboration to develop and implement these systems for the North African climate. Sweden has considerable experience in ground coupled systems, theoretically and practically, and there are presently more than 300.000 systems in operation in Sweden, mainly for heating. Most of these are small-scale heating systems for singe-family houses but during the last decade several hundred large-scale systems have been built for heating and cooling of

Model of a thermal energy storage device integrated into a solar assisted heat pump system for space heating

International Nuclear Information System (INIS)

Badescu, Viorel

2003-01-01

Details about modelling a sensible heat thermal energy storage (TES) device integrated into a space heating system are given. The two main operating modes are described. Solar air heaters provide thermal energy for driving a vapor compression heat pump. The TES unit ensures a more efficient usage of the collected solar energy. The TES operation is modeled by using two non-linear coupled partial differential equations for the temperature of the storage medium and heat transfer fluid, respectively. Preliminary results show that smaller TES units provide a higher heat flux to the heat pump vaporiser. This makes the small TES unit discharge more rapidly during time periods with higher thermal loads. The larger TES units provide heat during longer time periods, even if the heat flux they supply is generally smaller. The maximum heat flux is extracted from the TES unit during the morning. Both the heat pump COP and exergy efficiency decrease when the TES unit length increases. Also, the monthly thermal energy stored by the TES unit and the monthly energy necessary to drive the heat pump compressor are increased by increasing the TES unit length

Optimising building net energy demand with dynamic BIPV shading

International Nuclear Information System (INIS)

Jayathissa, P.; Luzzatto, M.; Schmidli, J.; Hofer, J.; Nagy, Z.; Schlueter, A.

2017-01-01

Highlights: •Coupled analysis of PV generation and building energy using adaptive BIPV shading. •20–80% net energy saving compared to an equivalent static system. •The system can in some cases compensate for the entire heating/cooling/lighting load. •High resolution radiation simulation including impacts of module self shading. -- Abstract: The utilisation of a dynamic photovoltaic system for adaptive shading can improve building energy performance by controlling solar heat gains and natural lighting, while simultaneously generating electricity on site. This paper firstly presents an integrated simulation framework to couple photovoltaic electricity generation to building energy savings through adaptive shading. A high-resolution radiance and photovoltaic model calculates the photovoltaic electricity yield while taking into account partial shading between modules. The remaining solar irradiation that penetrates the window is used in a resistance-capacitance building thermal model. A simulation of all possible dynamic configurations is conducted for each hourly time step, of which the most energy efficient configuration is chosen. We then utilise this framework to determine the optimal orientation of the photovoltaic panels to maximise the electricity generation while minimising the building’s heating, lighting and cooling demand. An existing adaptive photovoltaic facade was used as a case study for evaluation. Our results report a 20–80% net energy saving compared to an equivalent static photovoltaic shading system depending on the efficiency of the heating and cooling system. In some cases the Adaptive Solar Facade can almost compensate for the entire energy demand of the office space behind it. The control of photovoltaic production on the facade, simultaneously with the building energy demand, opens up new methods of building management as the facade can control both the production and consumption of electricity.

Synergies of wind power and electrified space heating: case study for Beijing.

Science.gov (United States)

Chen, Xinyu; Lu, Xi; McElroy, Michael B; Nielsen, Chris P; Kang, Chongqing

2014-01-01

Demands for electricity and energy to supply heat are expected to expand by 71% and 47%, respectively, for Beijing in 2020 relative to 2009. If the additional electricity and heat are supplied solely by coal as is the current situation, annual emissions of CO2 may be expected to increase by 59.6% or 99 million tons over this interval. Assessed against this business as usual (BAU) background, the present study indicates that significant reductions in emissions could be realized using wind-generated electricity to provide a source of heat, employed either with heat pumps or with electric thermal storage (ETS) devices. Relative to BAU, reductions in CO2 with heat pumps assuming 20% wind penetration could be as large as 48.5% and could be obtained at a cost for abatement of as little as $15.6 per ton of avoided CO2. Even greater reductions, 64.5%, could be realized at a wind penetration level of 40% but at a higher cost, $29.4 per ton. Costs for reduction of CO2 using ETS systems are significantly higher, reflecting the relatively low efficiency for conversion of coal to power to heat.

Price, environment and security: Exploring multi-modal motivation in voluntary residential peak demand response

International Nuclear Information System (INIS)

Gyamfi, Samuel; Krumdieck, Susan

2011-01-01

Peak demand on electricity grids is a growing problem that increases costs and risks to supply security. Residential sector loads often contribute significantly to seasonal and daily peak demand. Demand response projects aim to manage peak demand by applying price signals and automated load shedding technologies. This research investigates voluntary load shedding in response to information about the security of supply, the emission profile and the cost of meeting critical peak demand in the customers' network. Customer willingness to change behaviour in response to this information was explored through mail-back survey. The diversified demand modelling method was used along with energy audit data to estimate the potential peak load reduction resulting from the voluntary demand response. A case study was conducted in a suburb of Christchurch, New Zealand, where electricity is the main source for water and space heating. On this network, all water heating cylinders have ripple-control technology and about 50% of the households subscribe to differential day/night pricing plan. The survey results show that the sensitivity to supply security is on par with price, with the emission sensitivity being slightly weaker. The modelling results show potential 10% reduction in critical peak load for aggregate voluntary demand response. - Highlights: → Multiple-factor behaviour intervention is necessarily for effective residential demand response. → Security signals can achieve result comparable to price. → The modelling results show potential 10% reduction in critical peak load for aggregate voluntary demand response. → New Zealand's energy policy should include innovation and development of VDR programmes and technologies.

Optimal usage of low temperature heat sources to supply district heating by heat pumps

DEFF Research Database (Denmark)

Pieper, Henrik; Ommen, Torben Schmidt; Markussen, Wiebke Brix

2017-01-01

This paper presents a theoretical study on the optimal usage of different low temperature heat sources to supply district heating by heat pumps. The study is based on data for the Copenhagen region. The heat sources were prioritized based on the coefficient of performance calculated for each hour...... and the covered demand of each heat source as well as required peak unit capacity. The results showed that heat pumps using different heat sources yield better performance than a heat pump based on a single one. The performance was influenced by the composition of the different heat sources. It was found that 78......% groundwater, 22% seawater and 0% air resulted in highest COP of 3.33 for the given heat demand. Furthermore, the implementation of rule based short term storage made peak units redundant. The variation in base load capacity showed that heat pumps utilizing the analyzed heat sources could perform very...

The role of district heating in future renewable energy systems

DEFF Research Database (Denmark)

Lund, Henrik; Möller, Bernd; Mathiesen, Brian Vad

2010-01-01

Based on the case of Denmark, this paper analyses the role of district heating in future Renewable Energy Systems. At present, the share of renewable energy is coming close to 20 per cent. From such point of departure, the paper defines a scenario framework in which the Danish system is converted...... to 100 per cent Renewable Energy Sources (RES) in the year 2060 including reductions in space heating demands by 75 per cent. By use of a detailed energy system analysis of the complete national energy system, the consequences in relation to fuel demand, CO2 emissions and cost are calculated for various...... as in a potential future system based 100 per cent on renewable energy....

Theoretical overview of heating power and necessary heating supply temperatures in typical Danish single-family houses from the 1900s

DEFF Research Database (Denmark)

Østergaard, Dorte Skaarup; Svendsen, Svend

2016-01-01

in typical Danish single-family houses constructed in the 1900s. The study provides a simplified theoretical overview of typical building constructions and standards for the calculation of design heat loss and design heating power in Denmark in the 1900s. The heating power and heating demand in six typical...... Danish single-family houses constructed in the 1900s were estimated based on simple steady-state calculations. We found that the radiators in existing single-family houses should not necessarilrbe expected to be over-dimensioned compared to current design heat loss. However, there is considerable...... potential for using low-temperature space heating in existing single-family houses in typical operation conditions. Older houses were not always found to require higher heating system temperatures than newer houses. We found that when these houses have gone through reasonable energy renovations, most...

Spatial Heat Planning and Heat Demand Reductions in Buildings

DEFF Research Database (Denmark)

Nielsen, Steffen

2013-01-01

to an energy system based 100% on renewable energy is not just a fi-ne-tuning of the existing system, but is a fundamental change of the entire energy system. However, similar to the use of fossil fuels, biomass re-sources, which account of a large share of the renewable energy sources, are limited in relation...... long-term savings in investments in production capacity and fuel costs. Through a case study, the amount of these long-term sav-ings is compared to the costs of implementing heat savings. The case study shows that heat reductions of roughly 50% are feasible if the long-term costs are included. Savings...

Critical evaluation of molybdenum and its alloys for use in space reactor core heat pipes

International Nuclear Information System (INIS)

Lundberg, L.B.

1981-01-01

The choice of pure molybdenum as the prime candidate material for space reactor core heat pipes is examined, and the advantages and disadvantages of this material are brought into focus. Even though pure molybdenum heat pipes have been built and tested, this metal's high ductile-brittle transition temperature and modest creep strength place significant design restrictions on a core heat pipe made from it. Molybdenum alloys are examined with regard to their promise as potential replacements for pure molybdenum. The properties of TZM and molybdenum-rhenium alloys are examined, and it appears that Mo-Re alloys with 10 to 15 wt % rhenium offer the most advantage as an alternative to pure molybdenum in space reactor core heat pipes

Heat Roadmap Europe

DEFF Research Database (Denmark)

David, Andrei; Mathiesen, Brian Vad; Averfalk, Helge

2017-01-01

The Heat Roadmap Europe (HRE) studies estimated a potential increase of the district heating (DH) share to 50% of the entire heat demand by 2050, with approximately 25–30% of it being supplied using large-scale electric heat pumps. This study builds on this potential and aims to document that suc......The Heat Roadmap Europe (HRE) studies estimated a potential increase of the district heating (DH) share to 50% of the entire heat demand by 2050, with approximately 25–30% of it being supplied using large-scale electric heat pumps. This study builds on this potential and aims to document...

Society demands for the quality of education as a factor of modern education space forming

Directory of Open Access Journals (Sweden)

Ivanova Svetlana V.

2016-01-01

Full Text Available The authors research the problems of increasing in modern conditions society demands for qualitative characteristics of education services. The quality of education is considered as one of the determining factors of forming educational space. The paper analyzes the influence of social and economic conditions inherent in the post-industrial era on forming and transforming of education space at the modern stage of society development, shows the ways to overcome emerging contradictions. The authors pay special attention to the significance of project approach in solving the problems of improving education quality.

WinSim: A simple simulation program for evaluating the influence of windows on heating demand and risk of overheating

DEFF Research Database (Denmark)

Schultz, Jørgen Munthe; Svendsen, Sv Aa Højgaard

1998-01-01

A two-node model of a room has been implemented in a computer program, WinSim, devel-oped for evaluation of thermal performance of windows in new buildings and in case of retro-fitting. The program calculates the annual heating demand and the number of hours with in-door temperatures higher than...... a user defined limit. WinSim is characterised by the limited amount of required input data. Guide-lines for calculation of the effective thermal capacity of the room is given, and results obtained with WinSim have been compared to results from an advanced building simulation program. Good agreement has...... been found between the two programs with respect to calculated annual heating demand and energy savings due to win-dow exchange, and also the calculated number of hours with overtemperature is similar. Based on the limited examples used for the comparison it can be concluded that WinSim is well suited...

Warm homes: Drivers of the demand for heating in the residential sector in New Zealand

International Nuclear Information System (INIS)

Howden-Chapman, Philippa; Viggers, Helen; Chapman, Ralph; O'Dea, Des; Free, Sarah; O'Sullivan, Kimberley

2009-01-01

New Zealand houses are large, often poorly constructed and heated, by OECD standards, and consequently are colder and damper indoors than recommended by the World Health Organisation. This affects both the energy consumption and the health of households. The traditional New Zealand household pattern of only heating one room of the house has been unchanged for decades, although there has been substantial market penetration of unflued gas heaters and more recently heat pumps. This paper describes the residential sector and the results of two community-based trials of housing and heating interventions that have been designed to measure the impact of (1) retrofitting insulation and (2) replacing unflued gas heaters and electric resistance heaters with heat pumps, wood pellet burners and flued gas heaters. The paper describes findings on the rebound effect or 'take-back'-the extent to which households take the gains from insulation and heating improvements as comfort (higher temperatures) rather than energy savings, and compares energy-saving patterns with those suggested by an earlier study. Findings on these aspects of household space heating are discussed in the context of the New Zealand government's policy drive for a more sustainable energy system, and the implications for climate change policy.

Laboratory Evaluation of Gas-Fired Tankless and Storage Water Heater Approaches to Combination Water and Space Heating

Energy Technology Data Exchange (ETDEWEB)

Kingston, T.; Scott, S.

2013-03-01

Homebuilders are exploring more cost effective combined space and water heating systems (combo systems) with major water heater manufacturers that are offering pre-engineered forced air space heating combo systems. In this project, unlike standardized tests, laboratory tests were conducted that subjected condensing tankless and storage water heater based combo systems to realistic, coincidental space and domestic hot water loads with the following key findings: 1) The tankless combo system maintained more stable DHW and space heating temperatures than the storage combo system. 2) The tankless combo system consistently achieved better daily efficiencies (i.e. 84%-93%) than the storage combo system (i.e. 81%- 91%) when the air handler was sized adequately and adjusted properly to achieve significant condensing operation. When condensing operation was not achieved, both systems performed with lower (i.e. 75%-88%), but similar efficiencies. 3) Air handlers currently packaged with combo systems are not designed to optimize condensing operation. More research is needed to develop air handlers specifically designed for condensing water heaters. 4) System efficiencies greater than 90% were achieved only on days where continual and steady space heating loads were required with significant condensing operation. For days where heating was more intermittent, the system efficiencies fell below 90%.

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

Regenerative heat sources for heating networks

International Nuclear Information System (INIS)

Huenges, Ernst; Sperber, Evelyn; Eggers, Jan-Bleicke; Noll, Florian; Kallert, Anna Maria; Reuss, Manfred

2015-01-01

The ambitious goal, the German Federal Government has set itself, to reduce the emissions of greenhouse gases by 80% to 95% by the year 2050. As there are currently more than half of German energy consumption for the production of heat is required, big contributions to climate protection can be expected from this area if more renewable heat sources are used. Renewable heat sources such as bioenergy, solar thermal and geothermal energy in particular can be provided as compared to fossil fuels with significantly lower specific CO 2 emissions. Objectives in the heating market and scenarios for the transformation of the heat sector have been elaborated in the BMU Lead Study 2011. The main pillar of this scenario is the reduction of final energy consumption for heat by the energy-efficient renovation of existing buildings and further increasing demands on the energetic quality of new buildings. To cover the remaining energy demand, a focus is on the expansion of heating networks based on renewable energies. [de

Development and test of a space-reactor-core heat pipe

International Nuclear Information System (INIS)

Merrigan, M.A.; Runyan, J.E.; Martinez, H.E.; Keddy, E.S.

1983-01-01

A heat pipe designed to meet the heat transfer requirements of a 100-kW/sub e/ space nuclear power system has been developed and tested. General design requirements for the device included an operating temperature of 1500 0 K with an evaporator radial flux density of 100 w/cm 2 . The total heat-pipe length of 2 m comprised an evaporator length of 0.3 m, a 1.2-m adiabatic section, and a condenser length of 0.5 m. A four-artery design employing screen arteries and distribution wicks was used with lithium serving as the working fluid. Molybdenum alloys were used for the screen materials and tube shell. Hafnium and zirconium gettering materials were used in connection with a pre-purified distilled lithium charge to ensure internal chemical compatibility. After initial performance verification, the 14.1-mm i.d. heat pipe was operated at 15 kW throughput at 1500 0 K for 100 hours. No performance degradation was observed during the test

District heating and heat storage using the solution heat of an ammonia/water system

International Nuclear Information System (INIS)

Taube, M.; Peier, W.; Mayor, J.C.

1976-01-01

The article describes a model for the optimum use of the heat energy generated in a nuclear power station for district heating and heat storage taking account of the electricity and heat demand varying with time. (HR/AK) [de

The space heating market and the big customers; Vaermemarknaden och storkunderna

Energy Technology Data Exchange (ETDEWEB)

Maardsjoe, Olle

2007-07-01

This report focuses on the cost of heating in multiple-occupancy buildings, commercial premises and industrial premises. A summary has been created of the development of heating, primarily in the 2000s, for as long as statistics are available (essentially 2004). Total heating has seen a reduction over the period as regards both total usage and specifically in kWh/sq. m. District heating, on the other hand, has seen an increase in total turnover, now accounting for around two-thirds of demand - or about 42 TWh - as well. The increase in district heating has come about partly as a result of property renovation and people exchanging their sources of heating. A reduction in oil consumption has been the primary cause of this transition. There has also been a slight increase in the number of heat pumps in use. In total, heat pumps account for a small proportion of the heating of the properties in question. Heating costs account for a large proportion of operating expenses for property owners, in fact up to 40-50 percent of ongoing operating expenses. Reducing the cost of heating is very important, as this directly affects the property owners' bottom lines. Contractors are offering services to help property owners to optimise their energy-saving measures. The price of district heating, where this is available, is being used as a basis. This is why the structure of the price of district heating affects what measures are implemented. In price constructions with too high a flexible element, there is plenty of incentive to make savings on energy. District heating suppliers' coverage of set costs is reduced once the measures to ensure savings have been implemented, and so they have to increase their prices retrospectively. In price constructions with a high set element, there is little incentive to make savings, with a subsequent increase in demand for heating in extreme cases. District heating suppliers can be forced to make investments in both generation and

Combined heat pump for sanitary hot water and space heating with CO{sub 2} as refrigerant; Kombineret brugsvands- og rumvarmepumpe med CO{sub 2} som koelemiddel

Energy Technology Data Exchange (ETDEWEB)

Schoen Poulsen, C. [Teknologisk Institut (Denmark)

2006-05-19

This project report describes the implementation of the Danish project called 'Combined heat pump for sanitary hot water and space heating with CO{sub 2} as refrigerant'. In the course of the project, a combined heat pump has been developed for heating sanitary hot water and producing domestic space heating. The project shows that CO2 has excellent properties in systems where a high temperature is desired on the gas cooler side and that it is possible to combine the production of sanitary hot water with the production of domestic space heating. During the project, a number of system solutions have been analysed and at the end of the project a prototype was built. It was tested in the laboratory according to a current Dutch standard for heat pumps for sanitary hot water. The prototype was constructed without the space heat part which solely has been analysed according to calculations. The reason is that there currently are no applicable European standards for the testing of combined systems and as the total efficiency of the system mainly depends on the temperature out of the gas cooler it was decided not to spend resources on the construction of the combined system in the prototype version of the unit. Instead, a number of proposals have been submitted to how the system with a space heat section could be constructed. The main components used in the prototype (compressor, exchangers, valve, control and tank) are all partly commercially available and therefore focus has been on the system construction. During the project, a number of CFD calculations have been carried out on the gas cooler in the hot water tank and the results show how important it is that the gas cooler is designed and placed correctly. The laboratory tests carried out on the unit show that the COP of the heat pump plant in connection with sanitary hot water tapping (according to Dutch standard) is 1.4 1.5 which is not immediately satisfactory. But when it is considered that the unit is a

Thermal performance analysis of a phase change thermal storage unit for space heating

Energy Technology Data Exchange (ETDEWEB)

Halawa, E.; Saman, W. [Institute for Sustainable Systems and Technologies School of Advanced Manufacturing and Mechanical Engineering, University of South Australia, Mawson Lakes SA 5095 (Australia)

2011-01-15

This paper presents the results of a comprehensive numerical study on the thermal performance of an air based phase change thermal storage unit (TSU) for space heating. The unit is designed for integration into space heating and cooling systems. The unit consists of a number of one dimensional phase change material (PCM) slabs contained in a rectangular duct where air passes between the slabs. The numerical analysis was based on an experimentally validated model. A parametric study has been carried out including the study on the effects of charge and discharge temperature differences, air mass flow rate, slab thicknesses, air gaps and slab dimensions on the air outlet temperatures and heat transfer rates of the thermal storage unit. The paper introduces and discusses quantities called charge and discharge temperature differences which play an important role in the melting and freezing processes. (author)

Solar heating, cooling, and domestic hot water system installed at Kaw Valley State Bank and Trust Company, Topeka, Kansas

Science.gov (United States)

1980-01-01

The building has approximately 5600 square feet of conditioned space. Solar energy was used for space heating, space cooling, and preheating domestic hot water (DHW). The solar energy system had an array of evacuated tube-type collectors with an area of 1068 square feet. A 50/50 solution of ethylene glycol and water was the transfer medium that delivered solar energy to a tube-in-shell heat exchanger that in turn delivered solar heated water to a 1100 gallon pressurized hot water storage tank. When solar energy was insufficient to satisfy the space heating and/or cooling demand, a natural gas-fired boiler provided auxiliary energy to the fan coil loops and/or the absorption chillers. Extracts from the site files, specification references, drawings, and installation, operation and maintenance instructions are presented.

Conceptual Design of a Condensing Heat Exchanger for Space Systems Using Porous Media

Science.gov (United States)

Hasan, Mohammad M.; Khan, Lutful I.; Nayagam, Vedha; Balasubramaniam, Ramaswamy

2006-01-01

Condensing heat exchangers are used in many space applications in the thermal and humidity control systems. In the International Space Station (ISS), humidity control is achieved by using a water cooled fin surface over which the moist air condenses, followed by "slurper bars" that take in both the condensate and air into a rotary separator and separates the water from air. The use of a cooled porous substrate as the condensing surface provides and attractive alternative that combines both heat removal as well as liquid/gas separation into a single unit. By selecting the pore sizes of the porous substrate a gravity independent operation may also be possible with this concept. Condensation of vapor into and on the porous surface from the flowing air and the removal of condensate from the porous substrate are the critical processes involved in the proposed concept. This paper describes some preliminary results of the proposed condensate withdrawal process and discusses the on-going design and development work of a porous media based condensing heat exchanger at the NASA Glenn Research Center in collaboration with NASA Johnson Space Center.

Space and Terrestrial Power System Integration Optimization Code BRMAPS for Gas Turbine Space Power Plants With Nuclear Reactor Heat Sources

Science.gov (United States)

Juhasz, Albert J.

2007-01-01

In view of the difficult times the US and global economies are experiencing today, funds for the development of advanced fission reactors nuclear power systems for space propulsion and planetary surface applications are currently not available. However, according to the Energy Policy Act of 2005 the U.S. needs to invest in developing fission reactor technology for ground based terrestrial power plants. Such plants would make a significant contribution toward drastic reduction of worldwide greenhouse gas emissions and associated global warming. To accomplish this goal the Next Generation Nuclear Plant Project (NGNP) has been established by DOE under the Generation IV Nuclear Systems Initiative. Idaho National Laboratory (INL) was designated as the lead in the development of VHTR (Very High Temperature Reactor) and HTGR (High Temperature Gas Reactor) technology to be integrated with MMW (multi-megawatt) helium gas turbine driven electric power AC generators. However, the advantages of transmitting power in high voltage DC form over large distances are also explored in the seminar lecture series. As an attractive alternate heat source the Liquid Fluoride Reactor (LFR), pioneered at ORNL (Oak Ridge National Laboratory) in the mid 1960's, would offer much higher energy yields than current nuclear plants by using an inherently safe energy conversion scheme based on the Thorium --> U233 fuel cycle and a fission process with a negative temperature coefficient of reactivity. The power plants are to be sized to meet electric power demand during peak periods and also for providing thermal energy for hydrogen (H2) production during "off peak" periods. This approach will both supply electric power by using environmentally clean nuclear heat which does not generate green house gases, and also provide a clean fuel H2 for the future, when, due to increased global demand and the decline in discovering new deposits, our supply of liquid fossil fuels will have been used up. This is

Optimization of operating parameters of ground source heat pump system for space heating and cooling by Taguchi method and utility concept

International Nuclear Information System (INIS)

Sivasakthivel, T.; Murugesan, K.; Thomas, H.R.

2014-01-01

Highlights: • Ground Source Heat Pump (GSHP) technology is suitable for both heating and cooling. • Important parameters that affect the GSHP performance has been listed. • Parameters of GSHP system has been optimized for heating and cooling mode. • Taguchi technique and utility concept are developed for GSHP optimization. - Abstract: Use of ground source energy for space heating applications through Ground Source Heat pump (GSHP) has been established as an efficient thermodynamic process. The electricity input to the GSHP can be reduced by increasing the COP of the system. However, the COP of a GSHP system will be different for heating and cooling mode operations. Hence in order to reduce the electricity input to the GSHP, an optimum value of COP has to be determined when GSHP is operated in both heating and cooling modes. In the present research, a methodology is proposed to optimize the operating parameters of a GSHP system which will operate on both heating and cooling modes. Condenser inlet temperature, condenser outlet temperature, dryness fraction at evaporator inlet and evaporator outlet temperature are considered as the influencing parameters of the heat pump. Optimization of these parameters for only heating or only cooling mode operation is achieved by employing Taguchi method for three level variations of the above parameters using an L 9 (3 4 ) orthogonal array. Higher the better concept has been used to get a higher COP. A computer program in FORTAN has been developed to carry out the computations and the results have been analyzed for the optimum conditions using Signal-to-Noise (SN) ratio and Analysis Of Variance (ANOVA) method. Based on this analysis, the maximum COP for only heating and only cooling operation are obtained as 4.25 and 3.32 respectively. By making use of the utility concept both the higher values of COP obtained for heating and cooling modes are optimized to get a single optimum COP for heating and cooling modes. A single

Dynamic simulation of space heating systems with radiators controlled by TRVs in buildings

Energy Technology Data Exchange (ETDEWEB)

Xu, Baoping; Fu, Lin; Di, Hongfa [Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084 (China)

2008-07-01

The objective of this paper is to develop a model for simulating the thermal and hydraulic behavior of space heating systems with radiators controlled by thermostat valves (TRVs) in multi-family buildings. This is done by treating the building and the heating system as a complete entity. Sub-models for rooms, radiators, TRVs, and the hydraulic network are derived. Then the suggested sub-models are combined to form an integrated model by considering interactions between them. The proposed model takes into account the heat transfer between neighboring rooms, the transport delay in the radiator, the self-adjusting function of the TRV, and the consumer's regulation behavior, as well as the hydraulic interactions between consumers. To test the model, two space heating systems in Beijing and Tianjin were investigated, and the model was validated under three operation modes. There was good agreement between the measured and simulated values for room temperature, return water temperature, and flow rate. A modeling analysis case was given based on an existing building and heating system. It was found that when the set value of the TRVs were kept on 2-3, about 12.4% reduction of heat consumption could be gained, compared with the situation in which the TRVs were kept fully open. The water flow rate was an important index that truly reflected the heat load change. It was also noted that if the flow rate or supply water temperature changed much during the transport delay time in the radiator, ignoring the transport delay would introduce an obvious deviation of the simulation results. Additionally, when an apartment stopped using the heating system during a heating season, the heat consumption of its neighboring apartments would be increased about 6-14%. (author)

Indirect control of flexible demand for power system applications

DEFF Research Database (Denmark)

Sossan, Fabrizio

This thesis addresses the topic of control of flexible demand to provide support to the operation of the electric power system. We focus on the indirect control approach, a framework that enables demand response by means of a consumption incentive signal. Initially, the concept of flexibility...... a shift in the consumption according to an indirect control signal. We present from simple control algorithms with a few requirements up to model predictive control strategies. The performance of the indirect control algorithms are compared by means of hardware-in-the-loop simulations using Power...... and storage in the operation of the future power system, we develop a model predictive control strategy for a smart building with the objective of supplying iii space heating and providing regulating power to the grid according to a dynamic electricity price. We named this application energy replacement...

Heating and cooling building energy demand evaluation; a simplified model and a modified degree days approach

International Nuclear Information System (INIS)

De Rosa, Mattia; Bianco, Vincenzo; Scarpa, Federico; Tagliafico, Luca A.

2014-01-01

Highlights: • A dynamic model to estimate the energy performance of buildings is presented. • The model is validated against leading software packages, TRNSYS and Energy Plus. • Modified degree days are introduced to account for solar irradiation effects. - Abstract: Degree days represent a versatile climatic indicator which is commonly used in building energy performance analysis. In this context, the present paper proposes a simple dynamic model to simulate heating/cooling energy consumption in buildings. The model consists of several transient energy balance equations for external walls and internal air according to a lumped-capacitance approach and it has been implemented utilizing the Matlab/Simulink® platform. Results are validated by comparison to the outcomes of leading software packages, TRNSYS and Energy Plus. By using the above mentioned model, energy consumption for heating/cooling is analyzed in different locations, showing that for low degree days the inertia effect assumes a paramount importance, affecting the common linear behavior of the building consumption against the standard degree days, especially for cooling energy demand. Cooling energy demand at low cooling degree days (CDDs) is deeply analyzed, highlighting that in this situation other factors, such as solar irradiation, have an important role. To take into account these effects, a correction to CDD is proposed, demonstrating that by considering all the contributions the linear relationship between energy consumption and degree days is maintained

Avoided economic impacts of energy demand changes by 1.5 and 2 °C climate stabilization

Science.gov (United States)

Park, Chan; Fujimori, Shinichiro; Hasegawa, Tomoko; Takakura, Jun’ya; Takahashi, Kiyoshi; Hijioka, Yasuaki

2018-04-01

Energy demand associated with space heating and cooling is expected to be affected by climate change. There are several global projections of space heating and cooling use that take into consideration climate change, but a comprehensive uncertainty of socioeconomic and climate conditions, including a 1.5 °C global mean temperature change, has never been assessed. This paper shows the economic impact of changes in energy demand for space heating and cooling under multiple socioeconomic and climatic conditions. We use three shared socioeconomic pathways as socioeconomic conditions. For climate conditions, we use two representative concentration pathways that correspond to 4.0 °C and 2.0 °C scenarios, and a 1.5 °C scenario driven from the 2.0 °C scenario with assumption in conjunction with five general circulation models. We find that the economic impacts of climate change are largely affected by socioeconomic assumptions, and global GDP change rates range from +0.21% to ‑2.01% in 2100 under the 4.0 °C scenario, depending on the socioeconomic condition. Sensitivity analysis that differentiates the thresholds of heating and cooling degree days clarifies that the threshold is a strong factor that generates these differences. Meanwhile, the impact of the 1.5 °C is small regardless of socioeconomic assumptions (‑0.02% to ‑0.06%). The economic loss caused by differences in socioeconomic assumption under the 1.5 °C scenario is much smaller than that under the 2 °C scenario, which implies that stringent climate mitigation can work as a risk hedge to socioeconomic development diversity.

The Liquid Droplet Radiator - an Ultralightweight Heat Rejection System for Efficient Energy Conversion in Space

Science.gov (United States)

Mattick, A. T.; Hertzberg, A.

1984-01-01

A heat rejection system for space is described which uses a recirculating free stream of liquid droplets in place of a solid surface to radiate waste heat. By using sufficiently small droplets ( 100 micron diameter) of low vapor pressure liquids the radiating droplet sheet can be made many times lighter than the lightest solid surface radiators (heat pipes). The liquid droplet radiator (LDR) is less vulnerable to damage by micrometeoroids than solid surface radiators, and may be transported into space far more efficiently. Analyses are presented of LDR applications in thermal and photovoltaic energy conversion which indicate that fluid handling components (droplet generator, droplet collector, heat exchanger, and pump) may comprise most of the radiator system mass. Even the unoptimized models employed yield LDR system masses less than heat pipe radiator system masses, and significant improvement is expected using design approaches that incorporate fluid handling components more efficiently. Technical problems (e.g., spacecraft contamination and electrostatic deflection of droplets) unique to this method of heat rejectioon are discussed and solutions are suggested.

Thermo-economic Optimization of Solar Assisted Heating and Cooling (SAHC System

Directory of Open Access Journals (Sweden)

A. Ghafoor

2014-12-01

Full Text Available The energy demand for cooling is continuously increasing due to growing thermal loads, changing architectural modes of building, and especially due to occupants indoor comfort requirements resulting higher electricity demand notably during peak load hours. This increasing electricity demand is resulting higher primary energy consumption and emission of green house gases (GHG due to electricity generation from fossil fuels. An exciting alternative to reduce the peak electricity consumption is the possible utilization of solar heat to run thermally driven cooling machines instead of vapor compression machines utilizing high amount of electricity. In order to widen the use of solar collectors, they should also be used to contribute for sanitary hot water production and space heating. Pakistan lying on solar belt has a huge potential to utilize solar thermal heat for heating and cooling requirement because cooling is dominant throughout the year and the enormous amount of radiation availability provides an opportunity to use it for solar thermal driven cooling systems. The sensitivity analysis of solar assisted heating and cooling system has been carried out under climatic conditions of Faisalabad (Pakistan and its economic feasibility has been calculated using maximization of NPV. Both storage size and collector area has been optimized using different economic boundary conditions. Results show that optimum area of collector lies between 0.26m2 to 0.36m2 of collector area per m2 of conditioned area for ieff values of 4.5% to 0.5%. The optimum area of collector increases by decreasing effective interest rate resulting higher solar fraction. The NPV was found to be negative for all ieff values which shows that some incentives/subsidies are needed to be provided to make the system cost beneficial. Results also show that solar fraction space heating varies between 87 and 100% during heating season and solar fraction cooling between 55 and 100% during

Electricity and heat supply of a settlement at different standards of energy efficiency; Strom- und Waermeversorgung einer Siedlung bei unterschiedlichen Energieeffizienz-Standards

Energy Technology Data Exchange (ETDEWEB)

Schuberth, Jens; Tschetschorke, Katja

2013-07-15

The underlying study analyses the ecologic impact and the economic efficiency of several conventional and innovative heat supply systems to provide a quarter heat for space and water heating and electricity for residential and commercial application and for street lighting. Retrofits of buildings change the ratio of demands for electricity and heat. The demand for heat decreases more than the demand for electricity, and the share of distribution losses in heat grids rises. The question is if it is still economically efficient to build or extend local and long-distance district heating networks. Demands for final and primary energy, greenhouse gas emissions and costs (for operation, energy consumption and investments) of the different systems are compared and rated both in charts and tables. A sensitivity analysis includes increasing energy purchasing costs and assesses the possible economic efficiency of the supply systems in future. Another sensitivity analysis estimates how the climate impact of the supply systems for heat and electricity changes if electricity generation becomes less harmful for climate. Additionally, costs for environmental damage - so-called external costs - are internalised in the analysis of economic efficiency. In an overall rating ecologic and economically efficient systems are recommended.

Spatiotemporal and economic analysis of industrial excess heat as a resource for district heating

DEFF Research Database (Denmark)

Bühler, Fabian; Petrović, Stefan; Holm, Fridolin Müller

2018-01-01

detailed analysis of the most suitable types of industries and the costs is required, allowing a targeted exploitation of this resource. This work extends the spatial and thermodynamic analysis, to account for the temporal match between industrial excess heat and district heating demands, as well...... as the costs for implementation and operation of the systems. This allows the determination of cost-effective district heating potentials, as well as the analysis of different industries and technological requirements. The results show that the temporal mismatch between excess heat and district heating demand...... and lack of demand, reduces the theoretical substitution potential by almost 30%. If heat storages are introduced, the total potential is reduced by only 10%. A majority of the excess heat can be utilised at socio-economic heating costs lower than the average Danish district heating price and the cost...

Demographic determinants of energy demand of households in Germany; Demografische Determinanten der Energienachfrage der Haushalte in Deutschland

Energy Technology Data Exchange (ETDEWEB)

Engel, Kerstin

2010-05-28

This thesis investigates in demographic determinants of energy demand of households in Germany, with focus on space heating and individual motor car traffic. Result of this thesis is a simulation model based on the approach of system dynamics, which is used to simulate two scenarios. The first scenario, called the reference scenario, is based on demographic data of the next decades, which is assumed to be realistic. The second alternative scenario runs without the probable demographic changes. By comparing the scenarios the role of demography in the range of energy demand is quantified. (orig.)

Electricity Demand Forecasting Using a Functional State Space Model

OpenAIRE

Nagbe , Komi; Cugliari , Jairo; Jacques , Julien

2018-01-01

In the last past years the liberalization of the electricity supply, the increase variability of electric appliances and their use, and the need to respond to the electricity demand in the real time had made electricity demand forecasting a challenge. To this challenge, many solutions are being proposed. The electricity demand involves many sources such as economic activities, household need and weather sources. All this sources make hard electricity demand forecasting. To forecast the electr...

Green Space and Deaths Attributable to the Urban Heat Island Effect in Ho Chi Minh City.

Science.gov (United States)

Dang, Tran Ngoc; Van, Doan Quang; Kusaka, Hiroyuki; Seposo, Xerxes T; Honda, Yasushi

2018-04-01

To quantify heat-related deaths in Ho Chi Minh City, Vietnam, caused by the urban heat island (UHI) and explore factors that may alleviate the impact of UHIs. We estimated district-specific meteorological conditions from 2010 to 2013 using the dynamic downscaling model and calculated the attributable fraction and number of mortalities resulting from the total, extreme, and mild heat in each district. The difference in attributable fraction of total heat between the central and outer districts was classified as the attributable fraction resulting from the UHI. The association among attributable fraction, attributable number with a green space, population density, and budget revenue of each district was then explored. The temperature-mortality relationship between the central and outer areas was almost identical. The attributable fraction resulting from the UHI was 0.42%, which was contributed by the difference in temperature distribution between the 2 areas. Every 1-square-kilometer increase in green space per 1000 people can prevent 7.4 deaths caused by heat. Green space can alleviate the impacts of UHIs, although future studies conducting a heath economic evaluation of tree planting are warranted.

Simulation of hybrid ground-coupled heat pump with domestic hot water heating systems using HVACSIM+

Energy Technology Data Exchange (ETDEWEB)

Cui, Ping; Yang, Hongxing [Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong (China); Spitler, Jeffrey D. [School of Mechanical Engineering, Oklahoma State University (United States); Fang, Zhaohong [Ground Source Heat Pump Research Center, Shandong University of Architecture and Engineering, Jinan (China)

2008-07-01

A hybrid ground-coupled heat pump (HGCHP) with domestic hot water (DHW) supply system has been proposed in this paper for space cooling/heating and DHW supply for residential buildings in hot-climate areas. A simulation model for this hybrid system is established within the HVACSIM+ environment. A sample system, applied for a small residential apartment located in Hong Kong, is hourly simulated in a typical meteorological year. The conventional GCHP system and an electric heater for DHW supply are also modeled and simulated on an hourly basis within the HVACSIM+ for comparison purpose. The results obtained from this case study show that the HGCHP system can effectively alleviate the imbalanced loads of the ground heat exchanger (GHE) and can offer almost 95% DHW demand. The energy saving for DHW heating is about 70% compared with an electric heater. This proposed scheme, i.e. the HGCHP with DHW supply, is suitable to residential buildings in hot-climate areas, such as in Hong Kong. (author)

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

period required, economic viability, and operating conditions. One of the main issues impeding the utilization of the full potential of natural and renewable energy sources, e.g., solar and geothermal, for space heating and space cooling applications is the development of economically competitive......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 (seasonal) storage for the introduction of natural and renewable energy sources. TES systems for heating or cooling are utilized in applications where there is a time mismatch between the demand and the most economically favorable supply of energy. The selection of a TES system mainly depends on the storage...

Household energy demand. Empirical studies concerning Sweden

Energy Technology Data Exchange (ETDEWEB)

Dargay, J; Lundin, A

1978-06-01

This paper investigates the effects of energy policy on households in Sweden and provides the material necessary for evaluation of current and proposed energy-conservation measures. Emphasis is placed on the impact of enery taxation or price changes on household demand for electricity, heating oil, and gasoline and the consequences of such measures for income distribution. The results of the Swedish studies of household demand for heating oil and gasoline indicate that price changes can have a considerable long run impact on fuel utilization. In the short run, price responsiveness is notably reduced, but it is nevertheless of consequence for energy demand.

Solar heating, cooling, and domestic hot water system installed at Kaw Valley State Bank and Trust Company, Topeka, Kansas. Final report

Energy Technology Data Exchange (ETDEWEB)

None

1980-11-01

The building has approximately 5600 square feet of conditioned space. Solar energy is used for space heating, space cooling, and preheating domestic hot water (DHW). The solar energy system has an array of evacuated tube-type collectors with an area of 1068 square feet. A 50/50 solution of ethylene glycol and water is the transfer medium that delivers solar energy to a tube-in-shell heat exchanger that in turn delivers solar-heated water to a 1100 gallon pressurized hot water storage tank. When solar energy is insufficient to satisfy the space heating and/or cooling demand, a natural gas-fired boiler provides auxiliary energy to the fan coil loops and/or the absorption chillers. Extracts from the site files, specification references, drawings, and installation, operation and maintenance instructions are included.

Ultra-Low Heat-Leak, High-Temperature Superconducting Current Leads for Space Applications

Science.gov (United States)

Rey, Christopher M.

2013-01-01

NASA Goddard Space Flight Center has a need for current leads used in an adiabatic demagnetization refrigerator (ADR) for space applications. These leads must comply with stringent requirements such as a heat leak of approximately 100 W or less while conducting up to 10 A of electric current, from more than 90 K down to 10 K. Additionally, a length constraint of leak leads currently to NASA's specs.

APPLICATIONS OF THERMAL ENERGY STORAGE TO WASTE HEAT RECOVERY IN THE FOOD PROCESSING INDUSTRY, Final Report

Energy Technology Data Exchange (ETDEWEB)

Lundberg, W. L.; Christenson, James A.

1979-07-31

A project is discussed in which the possibilities for economical waste heat recovery and utilization in the food industry were examined. Waste heat availability and applications surveys were performed at two manufacturing plants engaged in low temperature (freezing) and high temperature (cooking, sterilizing, etc.) food processing. The surveys indicate usable waste heat is available in significant quantities which could be applied to existing, on-site energy demands resulting in sizable reductions in factory fuel and energy usage. At the high temperature plant, the energy demands involve the heating of fresh water for boiler make-up, for the food processes and for the daily clean-up operation. Clean-up poses an opportunity for thermal energy storage since waste heat is produced during the one or two production shifts of each working day while the major clean-up effort does not occur until food production ends. At the frozen food facility, the clean-up water application again exists and, in addition, refrigeration waste heat could also be applied to warm the soil beneath the ground floor freezer space. Systems to recover and apply waste heat in these situations were developed conceptually and thermal/economic performance predictions were obtained. The results of those studies indicate the economics of waste heat recovery can be attractive for facilities with high energy demand levels. Small factories, however, with relatively low energy demands may find the economics marginal although, percentagewise, the fuel and energy savings are appreciable.

Integration of available regenerative energy sources in community networks for both electricity and heating

Energy Technology Data Exchange (ETDEWEB)

Alcalde Melo, Henrique

2013-03-06

In the last years, energy prices for German households have been increasing constantly. Some reasons for that include: the dependency of Germany on external fossil fuels to supply its energy demand, the decision to invest in renewable energy generation and to shut down all its nuclear power plants. Nowadays households are already able to generate energy on-site, however the generation potential depends on climatic conditions as well as the specific location and the type of the building. The aim of this work is to evaluate whether a community of new efficient single-family houses can generate enough energy on-site to supply its electricity and heating demand over the year based on renewable energy sources and with the support of energy storage systems, including electric vehicles. The theoretical community is situated in the city of Cottbus, Germany. For this community, an electricity load profile was designed based on the use of common devices and separated in controllable and uncontrollable loads. Electricity is generated on-site through photovoltaic panels and small wind turbines, and the electricity generation potential is evaluated based on the community's available space, which is rather limited, and the actual regulations in the State of Brandenburg. A comparison of the available technologies to supply the heating demand as well as to store energy in the household sector is presented and discussed. It is assumed that each household has an electric vehicle that can be charged and also discharged in the community as an extra energy storage system. A software simulation system was designed with which an energy balance analysis is carried out based on hourly values of supply and demand. Under the assumptions taken for this study, the results of the simulation show that the community is able to generate more energy than consumed throughout a year, however in a few occasions there is not enough energy available to supply the community's energy demand

Integration of available regenerative energy sources in community networks for both electricity and heating

Energy Technology Data Exchange (ETDEWEB)

Alcalde Melo, Henrique

2013-03-06

In the last years, energy prices for German households have been increasing constantly. Some reasons for that include: the dependency of Germany on external fossil fuels to supply its energy demand, the decision to invest in renewable energy generation and to shut down all its nuclear power plants. Nowadays households are already able to generate energy on-site, however the generation potential depends on climatic conditions as well as the specific location and the type of the building. The aim of this work is to evaluate whether a community of new efficient single-family houses can generate enough energy on-site to supply its electricity and heating demand over the year based on renewable energy sources and with the support of energy storage systems, including electric vehicles. The theoretical community is situated in the city of Cottbus, Germany. For this community, an electricity load profile was designed based on the use of common devices and separated in controllable and uncontrollable loads. Electricity is generated on-site through photovoltaic panels and small wind turbines, and the electricity generation potential is evaluated based on the community's available space, which is rather limited, and the actual regulations in the State of Brandenburg. A comparison of the available technologies to supply the heating demand as well as to store energy in the household sector is presented and discussed. It is assumed that each household has an electric vehicle that can be charged and also discharged in the community as an extra energy storage system. A software simulation system was designed with which an energy balance analysis is carried out based on hourly values of supply and demand. Under the assumptions taken for this study, the results of the simulation show that the community is able to generate more energy than consumed throughout a year, however in a few occasions there is not enough energy available to supply the community's energy demand. Water can be

District space heating potential of low temperature hydrothermal geothermal resources in the southwestern United States. Technical report

Energy Technology Data Exchange (ETDEWEB)

McDevitt, P.K.; Rao, C.R.

1978-10-01

A computer simulation model (GIRORA-Nonelectric) is developed to study the economics of district space heating using geothermal energy. GIRORA-Nonelectric is a discounted cashflow investment model which evaluates the financial return on investment for space heating. This model consists of two major submodels: the exploration for and development of a geothermal anomaly by a geothermal producer, and the purchase of geothermal fluid by a district heating unit. The primary output of the model is a calculated rate of return on investment earned by the geothermal producer. The results of the sensitivity analysis of the model subject to changes in physical and economic parameters are given in this report. Using the results of the economic analysis and technological screening criteria, all the low temperature geothermal sites in Southwestern United States are examined for economic viability for space heating application. The methodology adopted and the results are given.

Measurement and analysis of SPS kicker magnet heating and outgassing with Different Bunch Spacing

CERN Document Server

Barnes, M J; Cornelis, K; Ducimetière, L; Mahner, E; Papotti, G; Rumolo, G; Senaj, V; Shaposhnikova, E

2010-01-01

Fast kicker magnets are used to inject beam into and eject beam out of the CERN SPS accelerator ring. These kickers are generally ferrite loaded transmission line type magnets with a rectangular shaped aperture through which the beam passes. Unless special precautions are taken the impedance of the ferrite yoke can provoke significant beam induced heating, over several hours, even above the Curie temperature of the ferrite. At present the nominal bunch spacing in the SPS is 25 ns, however for an early stage of LHC operation it is preferable to have 50 ns bunch spacing. Machine Development (MD) studies have been carried out with an inter-bunch spacing of 25 ns, 50 ns or 75 ns. For some of the SPS kicker magnets the 75 ns bunch spacing resulted in considerable beam induced heating. In addition the MDs showed that 50 ns bunch spacing could result in a very rapid pressure rise in the kicker magnet and thus cause an interlock. This paper discusses the MD observations of the SPS kickers and analyses the available d...

Space and time variability of heating requirements for greenhouse tomato production in the Euro-Mediterranean area.

Science.gov (United States)

Mariani, Luigi; Cola, Gabriele; Bulgari, Roberta; Ferrante, Antonio; Martinetti, Livia

2016-08-15

The Euro-Mediterranean area is the seat of a relevant greenhouse activity, meeting the needs of important markets. A quantitative assessment of greenhouse energy consumption and of its variability in space and time is an important decision support tool for both greenhouse-sector policies and farmers. A mathematical model of greenhouse energy balance was developed and parameterized for a state-of-the-art greenhouse to evaluate the heating requirements for vegetables growing. Tomato was adopted as reference crop, due to its high energy requirement for fruit setting and ripening and its economic relevance. In order to gain a proper description of the Euro-Mediterranean area, 56 greenhouse areas located within the ranges 28°N-72°N and 11°W-55°E were analyzed over the period 1973-2014. Moreover, the two 1973-1987 and 1988-2014 sub-periods were separately studied to describe climate change effects on energy consumption. Results account for the spatial variability of energy needs for tomato growing, highlighting the strong influence of latitude on the magnitude of heat requirements. The comparison between the two selected sub-periods shows a decrease of energy demand in the current warm phase, more relevant for high latitudes. Finally, suggestions to reduce energy consumptions are provided. Copyright © 2016 Elsevier B.V. All rights reserved.

Improvement of Thrust Bearing Calculation Considering the Convectional Heating within the Space between the Pads

Directory of Open Access Journals (Sweden)

Monika Chmielowiec-Jablczyk

2018-02-01

Full Text Available A modern thrust bearing tool is used to estimate the behavior of tilting pad thrust bearings not only in the oil film between pad and rotating collar, but also in the space between the pads. The oil flow in the space significantly influences the oil film inlet temperature and the heating of pad and collar. For that reason, it is necessary to define an oil mixing model for the space between the pads. In the bearing tool, the solutions of the Reynolds equation including a cavitation model, the energy equation and the heat transfer equation are done iteratively with the finite volume method by considering a constant flow rate. Both effects—laminar/turbulent flow and centrifugal force—are considered. The calculation results are compared with measurements done for a flooded thrust bearing with nominal eight tilting pads with an outer diameter of 180 mm. The heat convection coefficients for the pad surfaces mainly influence the pad temperature field and are adjusted to the measurement results. In the following paper, the calculation results for variable space distances, influence of different parameters on the bearing behavior and operating condition at high load are presented.

Forecasted electric power demands for the Baltimore Gas and Electric Company. Volume 1 and Volume 2. Documentation manual

International Nuclear Information System (INIS)

Estomin, S.L.; Beach, J.E.; Goldsmith, J.V.

1991-05-01

The two-volume report presents the results of an econometric forecast of peak load and electric power demand for the Baltimore Gas and Electric Company (BG ampersand E) through the year 2009. Separate energy sales models were estimated for residential sales in Baltimore City, residential sales in the BG ampersand E service area excluding Baltimore City, commercial sales, industrial sales, streetlighting sales, and Company use plus losses. Econometric equations were also estimated for electric space heating and air conditioning saturation in Baltimore City and in the remainder of the BG ampersand E service territory. In addition to the energy sales models and the electric space conditioning saturation models, econometric models of summer and winter peak demand on the BG ampersand E system were estimated

Demonstrating a small utility approach to demand-side program implementation

International Nuclear Information System (INIS)

1991-01-01

The US DOE awarded a grant to the Burlington Electric Department (B.E.D.) to test a demand-side management (DSM) demonstration program designed to quickly save a significant amount of power with little disruption to the utility's customers or its normal operations. B.E.D. is a small municipal utility located in northern Vermont, with a lengthy history of successful DSM involvement. In our grant application, we proposed to develop a replicable program and approach to DSM that might be useful to other small utilities and to write a report to enable such replication. We believe that this DSM program and/or individual program components are replicable. This report is designed to allow other utilities interested in DSM to replicate this program or specific program design features to meet their DSM goals. We also wanted to use the opportunity of this grant to test the waters of residential heating fuel-switching. We hoped to test the application of one fuel-switching technology, and to benefit from the lessons learned in developing a full-scale DSM program for this end- use. To this end the pilot effort has been very successful. In the pilot pressure we installed direct-vent gas fired space heaters sized as supplemental heating units in 44 residences heated solely by electric resistance heat. We installed the gas space heating units at no cost to the owners or residents. We surveyed participating customers. The results of those surveys are included in this report and preliminary estimates of winter peak capacity load reductions are also noted in this report

Demonstrating a small utility approach to demand-side program implementation

Energy Technology Data Exchange (ETDEWEB)

1991-10-01

The US DOE awarded a grant to the Burlington Electric Department (B.E.D.) to test a demand-side management (DSM) demonstration program designed to quickly save a significant amount of power with little disruption to the utility's customers or its normal operations. B.E.D. is a small municipal utility located in northern Vermont, with a lengthy history of successful DSM involvement. In our grant application, we proposed to develop a replicable program and approach to DSM that might be useful to other small utilities and to write a report to enable such replication. We believe that this DSM program and/or individual program components are replicable. This report is designed to allow other utilities interested in DSM to replicate this program or specific program design features to meet their DSM goals. We also wanted to use the opportunity of this grant to test the waters of residential heating fuel-switching. We hoped to test the application of one fuel-switching technology, and to benefit from the lessons learned in developing a full-scale DSM program for this end- use. To this end the pilot effort has been very successful. In the pilot pressure we installed direct-vent gas fired space heaters sized as supplemental heating units in 44 residences heated solely by electric resistance heat. We installed the gas space heating units at no cost to the owners or residents. We surveyed participating customers. The results of those surveys are included in this report and preliminary estimates of winter peak capacity load reductions are also noted in this report.

Solar chimney: A sustainable approach for ventilation and building space conditioning

Directory of Open Access Journals (Sweden)

Lal, S.,

2013-03-01

Full Text Available The residential and commercial buildings demand increase with rapidly growing population. It leads to the vertical growth of the buildings and needs proper ventilation and day-lighting. The natural air ventilation system is not significantly works in conventional structure, so fans and air conditioners are mandatory to meet the proper ventilation and space conditioning. Globally building sector consumed largest energy and utmost consumed in heating, ventilation and space conditioning. This load can be reduced by application of solar chimney and integrated approaches in buildings for heating, ventilation and space conditioning. It is a sustainable approach for these applications in buildings. The authors are reviewed the concept, various method of evaluation, modelings and performance of solar chimney variables, applications and integrated approaches.

Heat transport analysis in a district heating and snow melting system in Sapporo and Ishikari, Hokkaido applying waste heat from GTHTR300

International Nuclear Information System (INIS)

Kasahara, Seiji; Kamiji, Yu; Terada, Atsuhiko; Yan Xing; Inagaki, Yoshiyuki; Murata, Tetsuya; Mori, Michitsugu

2015-01-01

A district heating and snow melting system utilizing waste heat from Gas Turbine High temperature Gas Reactor of 300 MW_e (GTHTR300), a heat-electricity cogeneration design of high temperature gas-cooled reactor, was analyzed. Application areas are set in Sapporo and Ishikari, the heavy snowfall cities in Northern Japan. The heat transport analyses are carried out by modeling the components in the system; pipelines of the secondary water loops between GTHTR300s and heat demand district and heat exchangers to transport the heat from the secondary water loops to the tertiary loops in the district. Double pipe for the secondary loops are advantageous for less heat loss and smaller excavation area. On the other hand, these pipes has disadvantage of more electricity consumption for pumping. Most of the heat demand in the month of maximum requirement can be supplied by 2 GTHTR300s and delivered by 9 secondary loops and around 5000 heat exchangers. Closer location of GTHTR300 site to the heat demand district is largely advantageous economically. Less decrease of the distance from 40 km to 20 km made the heat loss half and cost of the heat transfer system 22% smaller. (author)

A quasi-transient model of a transcritical carbon dioxide direct-expansion ground source heat pump for space and water heating

International Nuclear Information System (INIS)

Eslami-Nejad, Parham; Ouzzane, Mohamed; Aidoun, Zine

2015-01-01

In this study, a theoretical quasi-transient model is developed for detailed simulations of a carbon dioxide (CO_2) direct-expansion ground source heat pump (DX-GSHP). This model combines a transient analytical model for the ground, steady-state numerical models for the borehole and the gas cooler, as well as several thermodynamic models for the remaining components of a conventional heat pump, organized in interacting subroutines to form a powerful simulation tool. Extensive validation combining experimental data and CFD-generated results was performed for the borehole before the tool was used to simulate a practical application case. Performance is investigated for a system satisfying both space heating and domestic hot water requirements of a typical single family detached home in a cold climate region. The variation of different system parameters is also evaluated in this study. It is shown that CO_2 DX-GSHPs can offer relatively efficient and stable performance for integrated water and space heating applications. Furthermore, the importance of an accurate geothermal borehole sizing is highlighted for the DX-CO_2 heat pump systems. It is shown that, due to changes in the system working conditions, the total borehole length is not linearly correlated with the heat pump energy consumption and other parameters such as heat pump coefficient of performance and pressure drop in ground heat exchangers. Results showed that increasing the total borehole length of an optimum design (reference case study) by 25% decreases the total annual energy consumption by only 6%. However, reducing total borehole length of the reference case by 25% increases the total annual energy consumption by 10%. - Highlights: • A quasi-transient model for CO_2 direct-exchange ground-source heat pump is developed. • Validation combining experimental data and CFD-generated results was performed. • The effect of the borehole size on the design parameters is evaluated. • Results show that

An optimisation framework for thermal energy storage integration in a residential heat pump heating system

International Nuclear Information System (INIS)

Renaldi, R.; Kiprakis, A.; Friedrich, D.

2017-01-01

Highlights: • An integrated framework for the optimal design of low carbon heating systems. • Development of a synthetic heat demand model with occupancy profiles. • Linear model of a heat pump with thermal energy storage heating system. • Evaluation of domestic heating system from generally available input parameters. • The lower carbon heating system can be cost competitive with conventional systems. - Abstract: Domestic heating has a large share in the UK total energy consumption and significant contribution to the greenhouse gas emissions since it is mainly fulfilled by fossil fuels. Therefore, decarbonising the heating system is essential and an option to achieve this is by heating system electrification through heat pumps (HP) installation in combination with renewable power generation. A potential increase in performance and flexibility can be achieved by pairing HP with thermal energy storage (TES), which allows the shifting of heat demand to off peak periods or periods with surplus renewable electricity. We present a design and operational optimisation model which is able to assess the performance of HP–TES relative to conventional heating systems. The optimisation is performed on a synthetic heat demand model which requires only the annual heat demand, temperature and occupancy profiles. The results show that the equipment and operational cost of a HP system without TES are significantly higher than for a conventional system. However, the integration of TES and time-of-use tariffs reduce the operational cost of the HP systems and in combination with the Renewable Heating Incentive make the HP systems cost competitive with conventional systems. The presented demand model and optimisation procedure will enable the design of low carbon district heating systems which integrate the heating system with the variable renewable electricity supply.

Heat savings in buildings in a 100% renewable heat and power system in Denmark with different shares of district heating

DEFF Research Database (Denmark)

Zvingilaite, Erika; Balyk, Olexandr

2014-01-01

levels of heat savings, which can be implemented by reducing heat transmission losses through building elements and by installing ventilation systems with heat recovery, in different future Danish heat and power system scenarios. Today almost 50% of heat demand in Denmark is covered by district heating......The paper examines implementation of heat saving measures in buildings in 2050, under the assumption that heat and power supply comes solely from renewable resources in Denmark.Balmorel – a linear optimisation model of heat and power sectors in Denmark is used for investigating economically viable....... A further expansion of district heating network in Denmark is assessed and penetration of heat savings is analysed in this context.If all heat saving measures, included in the model, are implemented, heat demand in Danish buildings in 2050 could be reduced by around 40%. Results show that it is cost...

Investigation of heat exchangers for energy conversion systems of megawatt-class space power plants

Science.gov (United States)

Ilmov, D. N.; Mamontov, Yu. N.; Skorohodov, A. S.; Smolyarov, V. A.; Filatov, N. I.

2016-01-01

The specifics of operation (high temperatures in excess of 1000 K and large pressure drops of several megapascals between "hot" and "cold" coolant paths) of heat exchangers in the closed circuit of a gasturbine power converter operating in accordance with the Brayton cycle with internal heat recovery are analyzed in the context of construction of space propulsion systems. The design of a heat-exchange matrix made from doubly convex stamped plates with a specific surface relief is proposed. This design offers the opportunity to construct heat exchangers with the required parameters (strength, rigidity, weight, and dimensions) for the given operating conditions. The diagram of the working area of a test bench is presented, and the experimental techniques are outlined. The results of experimental studies of heat exchange and flow regimes in the models of heat exchangers with matrices containing 50 and 300 plates for two pairs of coolants (gas-gas and gas-liquid) are detailed. A criterion equation for the Nusselt number in the range of Reynolds numbers from 200 to 20 000 is proposed. The coefficients of hydraulic resistance for each coolant path are determined as functions of the Reynolds number. It is noted that the pressure in the water path in the "gas-liquid" series of experiments remained almost constant. This suggests that no well-developed processes of vaporization occurred within this heat-exchange matrix design even when the temperature drop between gas and water was as large as tens or hundreds of degrees. The obtained results allow one to design flight heat exchangers for various space power plants.

A Data Analysis Approach for Diagnosing Malfunctioning in Domestic Space Heating

NARCIS (Netherlands)

Tabatabaei, S.

Around one third of worldwide energy usage is for the residential section and 60% of the energy consumption in this domestic area is for space heating. Therefore, monitoring and controlling this part of energy usage can have a major effect on the overall energy consumption and also on the emission

America: AGA [American Gas Association] initiative aims to boost gas demand

International Nuclear Information System (INIS)

Fraser, K.M.

1992-01-01

This article focuses on the aim of the American Gas Association to increase natural gas demand in the key areas of gas electric generation, natural gas vehicles, gas cooling, and conversion of oil burning facilities, electric water heaters and household appliances such as space heating, stoves, washers and lighting. The need to improve the reliability of natural gas supplies is discussed. It is anticipated that natural gas will not replace coal as the main energy source for power generation, but that it will help utilities to meet environmental regulations. (UK)

Urban climate and energy demand interaction in Northern Eurasia

Science.gov (United States)

Kasilova, E. V.; Ginzburg, A. S.; Demchenko, P. F.

2017-11-01

The regional and urban climate change in Northern Eurasia is one of the main challenges for sustainable development of human habitats situated in boreal and temperate areas. The half of primary energy is spent for space heating even under quite a mild European climate. Implementation of the district heating in urban areas is currently seen as one of the key conditions of sustainable development. The clear understanding of main problems of the urban climateenergy demand interaction is crucial for both small towns and megacities. The specific features of the urban energy systems in Finland, Russia and China under the changing climate conditions were studied. Regional manifestations of the climate change were examined. The climate projections were established for urban regions of the Northern Eurasia. It was shown that the climate warming is likely to continue intensively there. History and actual development trends were discussed for the urban district heating systems in Russia, China and Finland. Common challenges linked with the climate change have been identified for the considered areas. Adaptation possibilities were discussed taking into account climate-energy interactions.

Decomposing final energy use for heating in the residential sector in Austria

International Nuclear Information System (INIS)

Holzmann, Angela; Adensam, Heidelinde; Kratena, Kurt; Schmid, Erwin

2013-01-01

In Austria a considerable number of measures have been implemented to reduce final energy use for residential heating since the 1990s. The aim of this analysis is to investigate, why – despite these implemented measures – final energy use for heating has not decreased in the expected way. The impact of eight factors on final energy use for heating is quantified by applying the Logarithmic Mean Divisia Index (LMDI I) method. The dataset covers the sector of private households in Austria for the period from 1993 to 2009. The main findings of the analysis are: (1) while technical improvements reduce final energy use for heating significantly, rising comfort needs nearly outweigh these savings. (2) Consumer behaviour reduces calculated final energy use considerably. (3) The extent of this reduction is declining significantly in the period observed. (4) The growing share of single-family houses has increased energy demand for heating in the observed period, though a reversal of this trend is detected from 2007 onwards. (5) The impact of growing floor space per person is the major effect revealed by the analysis. (6) Weather conditions have a major impact on annual fluctuations of energy consumption. -- Highlights: •We did an Index decomposition analysis of the Austrian residential heating demand. •Eight impact factors on heating demand have been identified. •Rising comfort needs outweigh savings caused by technical improvements. •Consumer behaviour has a major impact on residential final energy use for heating. •Weather changes play a major role when analysing annual changes in energy use

Solar space heating for the visitors' center, Stephens College, Columbia, Missouri. Final report

Energy Technology Data Exchange (ETDEWEB)

Henley, Marion

1980-06-01

This document is the final report of the solar energy system located at the Visitors' Center on the Stephens College Campus, Columbia, Missouri. The system is installed in a four-story, 15,000 square foot building designed to include the college's Admission Office, nine guest rooms for overnight lodging for official guests of the college, a two-story art gallery, and a Faculty Lounge. The solar energy system is an integral design of the building and utilizes 176 Honeywell/Lennox hydronic flat-plate collectors which use a 50% water-ethylene glycol solution and water-to-water heat exchanger. Solar heated water is stored in a 5000 gallon water storage tank located in the basement equipment room. A natural gas fired hot water boiler supplies hot water when the solar energy heat supply fails to meet the demand. The designed solar contribution is 71% of the heating load. The demonstration period for this project ends June 30, 1984.

Competition in the market for space heating. District heating as the infrastructure for competition among fuels and technologies

International Nuclear Information System (INIS)

Grohnheit, Poul Erik; Gram Mortensen, Bent Ole

2003-01-01

None of the EU directives on liberalisation of the electricity and gas markets are considering the district heating systems, although the district heating networks offer the possibility of competition between natural gas and a range of other fuels on the market for space heating. Cogeneration of electricity and heat for industrial processes or district heating is a technology option for increased energy efficiency and thus reduction of CO 2 emissions. In the mid-1990s less than 10% of the electricity generation in the European Union was combined production with significant variations among Member States. These variations are explained by different national legislation and relative power of institutions, rather than difference in industrial structure, climate or urban physical structure. The 'single energy carrier' directives have provisions that support the development of combined heat and power (CHP), but they do not support the development and expansion of the district heating infrastructure. The article is partly based on a contribution to the Shared Analysis Project for the European Commission DG Energy, concerning the penetration of CHP, energy saving, and renewables as instruments to meet the targets of the Kyoto Protocol within the liberalised European energy market. The quantitative and legal differences of the heat markets in selected Member States are described, and the consequences of the directives are discussed. Finally, we summarise the tasks for a European policy concerning the future regulation of district heating networks for CHP, emphasising the need for rules for a fair competition between natural gas and district heating networks

Visualized study on specific points on demand curves and flow patterns in a single-side heated narrow rectangular channel

International Nuclear Information System (INIS)

Wang Junfeng; Huang Yanping; Wang Yanlin

2011-01-01

Highlights: → Specific points on the demand curve and flow patterns are visually studied. → Bubbly, churn, and annular flows were observed. → Onset of flow instability and bubbly-churn transition occurs at the same time. → The evolution of specific points and flow pattern transitions were examined. - Abstract: A simultaneous visualization and measurement study on some specific points on demand curves, such as onset of nucleate boiling (ONB), onset of significant void (OSV), onset of flow instability (OFI), and two-phase flow patterns in a single-side heated narrow rectangular channel, having a width of 40 mm and a gap of 3 mm, was carried out. New experimental approaches were adopted to identify OSV and OFI in a narrow rectangular channel. Under experimental conditions, the ONB could be predicted well by the Sato and Matsumura model. The OSV model of Bowring can reasonably predict the OSV if the single-side heated condition is considered. The OFI was close to the saturated boiling point and could be described accurately by Kennedy's correlation. The two-phase flow patterns observed in this experiment could be classified into bubbly, churn, and annular flow. Slug flow was never observed. The OFI always occurred when the bubbles at the channel exit began to coalesce, which corresponded to the beginning of the bubbly-churn transition in flow patterns. Finally, the evolution of specific points and flow pattern transitions were examined in a single-side heated narrow rectangular channel.

Energy Efficiency and Sustainability Evaluation of Space and Water Heating in Urban Residential Buildings of the Hot Summer and Cold Winter Zone in China

Directory of Open Access Journals (Sweden)

Xiao Chen

2016-09-01

Full Text Available With the urbanization process of the hot summer and cold winter (HSCW zone in China, the energy consumption of space and water heating in urban residential buildings of the HSCW zone has increased rapidly. This study presents the energy efficiency and sustainability evaluation of various ways of space and water heating taking 10 typical cities in the HSCW zone as research cases. Two indicators, primary energy efficiency (PEE and sustainability index based on exergy efficiency, are adopted to perform the evaluation. Models for the energy and total exergy efficiencies of various space and water heating equipment/systems are developed. The evaluation results indicate that common uses of electricity for space and water heating are the most unsustainable ways of space and water heating. In terms of PEE and sustainability index, air-source heat pumps for space and water heating are suitable for the HSCW zone. The PEE and sustainability index of solar water heaters with auxiliary electric heaters are greatly influenced by local solar resources. Air-source heat pump assisted solar hot water systems are the most sustainable among all water heating equipment/systems investigated in this study. Our works suggest the key potential for improving the energy efficiency and the sustainability of space and water heating in urban residential buildings of the HSCW zone.

Optimal study of a solar air heating system with pebble bed energy storage

International Nuclear Information System (INIS)

Zhao, D.L.; Li, Y.; Dai, Y.J.; Wang, R.Z.

2011-01-01

Highlights: → Use two kinds of circulation media in the solar collector. → Air heating and pebble bed heat storage are applied with different operating modes. → Design parameters of the system are optimized by simulation program. → It is found that the system can meet 32.8% of the thermal energy demand in heating season. → Annual solar fraction aims to be 53.04%. -- Abstract: The application of solar air collectors for space heating has attracted extensive attention due to its unique advantages. In this study, a solar air heating system was modeled through TRNSYS for a 3319 m 2 building area. This air heating system, which has the potential to be applied for space heating in the heating season (from November to March) and hot water supply all year around in North China, uses pebble bed and water storage tank as heat storage. Five different working modes were designed based on different working conditions: (1) heat storage mode, (2) heating by solar collector, (3) heating by storage bed, (4) heating at night and (5) heating by an auxiliary source. These modes can be operated through the on/off control of fan and auxiliary heater, and through the operation of air dampers manually. The design, optimization and modification of this system are described in this paper. The solar fraction of the system was used as the optimization parameter. Design parameters of the system were optimized by using the TRNSYS program, which include the solar collector area, installation angle of solar collector, mass flow rate through the system, volume of pebble bed, heat transfer coefficient of the insulation layer of the pebble bed and water storage tank, height and volume of the water storage tank. The TRNSYS model has been verified by data from the literature. Results showed that the designed solar system can meet 32.8% of the thermal energy demand in the heating season and 84.6% of the energy consumption in non-heating season, with a yearly average solar fraction of 53.04%.

Application of multi-criteria decision-making model for choice of the optimal solution for meeting heat demand in the centralized supply system in Belgrade

International Nuclear Information System (INIS)

Grujić, Miodrag; Ivezić, Dejan; Živković, Marija

2014-01-01

The expected growth of living standard, number of inhabitants and development of technology, industry and agriculture will cause a significant increase of energy consumption in cities. Three scenarios of energy sector development until 2030 and corresponding energy consumption for the city of Belgrade are analyzed in this paper. These scenarios consider different level of economic development, investments in energy sector, substitution of fossil fuels, introduction of renewable energy sources and implementation of energy efficiency measures. The proposed model for selection of optimal district heating system compares different options for fulfilling expected new heat demand through eight criteria for each scenario. Proposed options are combination of different energy sources and technologies for their use. The criteria weights are set according to Serbian economy and energy position. The criteria include financial aspects, environmental impact and availability of energy. Multi-criteria method ELECTRE (ELimination Et Choix Traduisant la REalite) is used as a tool for obtaining the optimal option. It is concluded that combination of CHP (combined heat and power) plant and centralized use of geothermal energy is optimal choice in the optimistic scenario. In the pessimistic and business as usual scenario the optimal option is combination of new gas boilers and centralized use of geothermal energy. - Highlights: • Three scenarios for meeting new heat demand are developed and assessed. • Constructing CHP (combined heat and power) is desirable in case of significant electricity price growth. • In all scenarios the chosen option includes using geothermal energy for heating

Mapping of potential heat sources for heat pumps for district heating in Denmark

International Nuclear Information System (INIS)

Lund, Rasmus; Persson, Urban

2016-01-01

The ambitious policy in Denmark on having a 100% renewable energy supply in 2050 requires radical changes to the energy systems to avoid an extensive and unsustainable use of biomass resources. Currently, wind power is being expanded and the increasing supply of electricity is slowly pushing the CHP (combined heat and power) plants out of operation, reducing the energy efficiency of the DH (district heating) supply. Here, large heat pumps for district heating is a frequently mentioned solution as a flexible demand for electricity and an energy efficient heat producer. The idea is to make heat pump use a low temperature waste or ambient heat source, but it has so far been very unclear which heat sources are actually available for this purpose. In this study eight categories of heat sources are analysed for the case of Denmark and included in a detailed spatial analysis where the identified heat sources are put in relation to the district heating areas and the corresponding demands. The analysis shows that potential heat sources are present near almost all district heating areas and that sea water most likely will have to play a substantial role as a heat source in future energy systems in Denmark. - Highlights: • The availability of heat sources for heat pumps in Denmark are mapped and quantified. • A novel methodology for assessment of low temperature industrial excess heat is presented. • There are heat sources available for 99% of district heating networks in Denmark. • The concentration of heat sources is generally bigger around bigger cities than smaller. • Ambient temperature heat sources will be more needed in district heating of big cities.

Estimation of demand function on natural gas and study of demand analysis

Energy Technology Data Exchange (ETDEWEB)

Kim, Y.D. [Korea Energy Economics Institute, Euiwang (Korea, Republic of)

1998-04-01

Demand Function is estimated with several methods about the demand on natural gas, and analyzed per usage. Since the demand on natural gas, which has big share of heating use, has a close relationship with temperature, the inter-season trend of price and income elasticity is estimated considering temperature and economic formation. Per usage response of natural gas demand on the changes of price and income is also estimated. It was estimated that the response of gas demand on the changes of price and income occurs by the change of number of users in long term. In case of the response of unit consumption, only industrial use shows long-term response to price. Since gas price barely responds to the change of exchange rate, it seems to express the price-making mechanism that does not reflect timely the import condition such as exchange rate, etc. 16 refs., 12 figs., 13 tabs.

Design package for a complete residential solar space heating and hot water system

Science.gov (United States)

1978-01-01

Information necessary to evaluate the design of a solar space heating and hot water system is reported. System performance specifications, the design data brochure, the system description, and other information pertaining to the design are included.

Practical versus theoretical domestic energy consumption for space heating

International Nuclear Information System (INIS)

Audenaert, A.; Briffaerts, K.; Engels, L.

2011-01-01

Methods to calculate the theoretical energy consumption consider several things: the number of degree days per year that need to be compensated by heating, the characteristics of the dwelling, the number of occupants and the characteristics of the installation for space heating and sanitary hot water. However, these methods do not take into account consumer behaviour, which may affect the actual consumption. The theoretical calculation methods are based on assumptions and use a number of standardized parameters. The difference between the actual and the theoretical energy consumption, and the impact of the residents' behaviour on energy consumption, is analysed by means of a literature study and a practical research. An energy advice procedure (EAP) audit is executed in five dwellings, as well as a survey regarding the energy related behaviour of the households. The theoretically calculated consumption is compared with the billed actual energy consumption of the families. The results show some problems with the current procedure and give some options to improve it. Some research needs are identified to gain more insights in the influence of different behavioural factors on the actual energy use for heating. - Highlights: → The energy advice procedure (EAP) calculates the energy use for heating in dwellings. → Calculations are compared with the real energy use for 5 dwellings. → A survey on the occupants' behaviour is used to interpret the observed differences. → Default values used in the EAP can be very different from the observed behaviour.

Practical versus theoretical domestic energy consumption for space heating

Energy Technology Data Exchange (ETDEWEB)

Audenaert, A., E-mail: amaryllis.audenaert@artesis.be [Department of Applied Engineering: Construction, Artesis University College of Antwerp, Paardenmarkt 92, B-2000 Antwerp (Belgium); Department of Environment, Technology and Technology Management, University of Antwerp, Prinsstraat 13, B-2000 Antwerp (Belgium); Briffaerts, K. [Unit Transition Energy and Environment, VITO NV, Boeretang 200, B-2400 Mol (Belgium); Engels, L. [Department of Applied Engineering: Construction, Artesis University College of Antwerp, Paardenmarkt 92, B-2000 Antwerp (Belgium)

2011-09-15

Methods to calculate the theoretical energy consumption consider several things: the number of degree days per year that need to be compensated by heating, the characteristics of the dwelling, the number of occupants and the characteristics of the installation for space heating and sanitary hot water. However, these methods do not take into account consumer behaviour, which may affect the actual consumption. The theoretical calculation methods are based on assumptions and use a number of standardized parameters. The difference between the actual and the theoretical energy consumption, and the impact of the residents' behaviour on energy consumption, is analysed by means of a literature study and a practical research. An energy advice procedure (EAP) audit is executed in five dwellings, as well as a survey regarding the energy related behaviour of the households. The theoretically calculated consumption is compared with the billed actual energy consumption of the families. The results show some problems with the current procedure and give some options to improve it. Some research needs are identified to gain more insights in the influence of different behavioural factors on the actual energy use for heating. - Highlights: > The energy advice procedure (EAP) calculates the energy use for heating in dwellings. > Calculations are compared with the real energy use for 5 dwellings. > A survey on the occupants' behaviour is used to interpret the observed differences. > Default values used in the EAP can be very different from the observed behaviour.

Large-size deployable construction heated by solar irradiation in free space

Science.gov (United States)

Pestrenina, Irena; Kondyurin, Alexey; Pestrenin, Valery; Kashin, Nickolay; Naymushin, Alexey

Large-size deployable construction in free space with subsequent direct curing was invented more than fifteen years ago (Briskman et al., 1997 and Kondyurin, 1998). It caused a lot of scientific problems, one of which is a possibility to use the solar energy for initiation of the curing reaction. This paper is devoted to investigate the curing process under sun irradiation during a space flight in Earth orbits. A rotation of the construction is considered. This motion can provide an optimal temperature distribution in the construction that is required for the polymerization reaction. The cylindrical construction of 80 m length with two hemispherical ends of 10 m radius is considered. The wall of the construction of 10 mm carbon fibers/epoxy matrix composite is irradiated by heat flux from the sun and radiates heat from the external surface by the Stefan- Boltzmann law. A stage of polymerization reaction is calculated as a function of temperature/time based on the laboratory experiments with certified composite materials for space exploitation. The curing kinetics of the composite is calculated for different inclination Low Earth Orbits (300 km altitude) and Geostationary Earth Orbit (40000 km altitude). The results show that • the curing process depends strongly on the Earth orbit and the rotation of the construction; • the optimal flight orbit and rotation can be found to provide the thermal regime that is sufficient for the complete curing of the considered construction. The study is supported by RFBR grant No.12-08-00970-a. 1. Briskman V., A.Kondyurin, K.Kostarev, V.Leontyev, M.Levkovich, A.Mashinsky, G.Nechitailo, T.Yudina, Polymerization in microgravity as a new process in space technology, Paper No IAA-97-IAA.12.1.07, 48th International Astronautical Congress, October 6-10, 1997, Turin Italy. 2. Kondyurin A.V., Building the shells of large space stations by the polymerisation of epoxy composites in open space, Int. Polymer Sci. and Technol., v.25, N4

Diamond wire cutting of heat exchangers

International Nuclear Information System (INIS)

Beckman, T.R.; Bjerler, J.

1991-01-01

With the change-out of equipment at nuclear power plants comes large quantities of low level contaminated metallic waste. Of particular concern are large heat exchangers, preheaters and steam generators. These bulky items consume huge volumes of burial space. The need for volume reduction and recycling of these metals has created new demands for 'how' to cut heat exchangers into useful sizes for decontamination, melting or compaction. This paper reviews the cutting solution provided by a diamond wire system, with particular regard for cutting of a Ringhals Preheater Bundle at Studsvik Nuclear in 1989. The background of diamond wire sawing is discussed and basic components of wire sawing are explained. Other examples of wire cutting decommissioned components are also given. (author)

Energy demand of the German and Dutch residential building stock under climate change

Science.gov (United States)

Olonscheck, Mady; Holsten, Anne; Walther, Carsten; Kropp, Jürgen P.

2014-05-01

In order to mitigate climate change, extraordinary measures are necessary in the future. The building sector, in particular, offers considerable potential for transformation to lower energy demand. On a national level, however, successful and far-reaching measures will likely be taken only if reliable estimates regarding future energy demand from different scenarios are available. The energy demand for space heating and cooling is determined by a combination of behavioral, climatic, constructional, and demographic factors. For two countries, namely Germany and the Netherlands, we analyze the combined effect of future climate and building stock changes as well as renovation measures on the future energy demand for room conditioning of residential buildings until 2060. We show how much the heating energy demand will decrease in the future and answer the question of whether the energy decrease will be exceeded by an increase in cooling energy demand. Based on a sensitivity analysis, we determine those influencing factors with the largest impact on the future energy demand from the building stock. Both countries have national targets regarding the reduction of the energy demand for the future. We provide relevant information concerning the annual renovation rates that are necessary to reach these targets. Retrofitting buildings is a win-win option as it not only helps to mitigate climate change and to lower the dependency on fossil fuels but also transforms the buildings stock into one that is better equipped for extreme temperatures that may occur more frequently with climate change. For the Netherlands, the study concentrates not only on the national, but also the provincial level, which should facilitate directed policy measures. Moreover, the analysis is done on a monthly basis in order to ascertain a deeper understanding of the future seasonal energy demand changes. Our approach constitutes an important first step towards deeper insights into the internal dynamics

Analysis on exergy consumption patterns for space heating in Slovenian buildings

DEFF Research Database (Denmark)

Dovjak, Mateja; Shukuya, Masanori; Olesen, Bjarne W.

2010-01-01

and demand is taken into consideration. Exergy calculations enable us to analyze how much exergy is consumed in which part, from boiler to building envelope. They also reveal how much energy is supplied for the purpose of heating. Results show that insulation has much bigger effect than effect of boiler...... efficiency. However, the most effective solution is to improve building envelope together with boiler efficiency. Better thermal insulation also makes an important contribution to the improvement of thermal comfort conditions. It causes higher surface temperatures resulting in a larger warm radiant exergy...... emission rate and consequently better thermal comfort....

Low temperature nuclear heat

Energy Technology Data Exchange (ETDEWEB)

Kotakorpi, J.; Tarjanne, R. [comps.

1977-08-01

The meeting was concerned with the use of low grade nuclear heat for district heating, desalination, process heat, and agriculture and aquaculture. The sessions covered applications and demand, heat sources, and economics.

User's manual for the Heat Pipe Space Radiator design and analysis Code (HEPSPARC)

Science.gov (United States)

Hainley, Donald C.

1991-01-01

A heat pipe space radiatior code (HEPSPARC), was written for the NASA Lewis Research Center and is used for the design and analysis of a radiator that is constructed from a pumped fluid loop that transfers heat to the evaporative section of heat pipes. This manual is designed to familiarize the user with this new code and to serve as a reference for its use. This manual documents the completed work and is intended to be the first step towards verification of the HEPSPARC code. Details are furnished to provide a description of all the requirements and variables used in the design and analysis of a combined pumped loop/heat pipe radiator system. A description of the subroutines used in the program is furnished for those interested in understanding its detailed workings.

Heat Transfer and Fluid Dynamics Measurements in the Expansion Space of a Stirling Cycle Engine

Science.gov (United States)

Jiang, Nan; Simon, Terrence W.

2006-01-01

The heater (or acceptor) of a Stirling engine, where most of the thermal energy is accepted into the engine by heat transfer, is the hottest part of the engine. Almost as hot is the adjacent expansion space of the engine. In the expansion space, the flow is oscillatory, impinging on a two-dimensional concavely-curved surface. Knowing the heat transfer on the inside surface of the engine head is critical to the engine design for efficiency and reliability. However, the flow in this region is not well understood and support is required to develop the CFD codes needed to design modern Stirling engines of high efficiency and power output. The present project is to experimentally investigate the flow and heat transfer in the heater head region. Flow fields and heat transfer coefficients are measured to characterize the oscillatory flow as well as to supply experimental validation for the CFD Stirling engine design codes. Presented also is a discussion of how these results might be used for heater head and acceptor region design calculations.

Heat pumps: heat recovery

Energy Technology Data Exchange (ETDEWEB)

Pielke, R

1976-01-01

The author firstly explains in a general manner the functioning of the heat pump. Following a brief look at the future heat demand and the possibilities of covering it, the various methods of obtaining energy (making use of solar energy, ground heat, and others) and the practical applications (office heating, swimming pool heating etc.) are explained. The author still sees considerable difficulties in using the heat pump at present on a large scale. Firstly there is not enough maintenance personnel available, secondly the electricity supply undertakings cannot provide the necessary electricity on a wide basis without considerable investments. Other possibilities to save energy or to use waste energy are at present easier and more economical to realize. Recuperative and regenerative systems are described.

Heating of large format filters in sub-mm and fir space optics

Science.gov (United States)

Baccichet, N.; Savini, G.

2017-11-01

Most FIR and sub-mm space borne observatories use polymer-based quasi-optical elements like filters and lenses, due to their high transparency and low absorption in such wavelength ranges. Nevertheless, data from those missions have proven that thermal imbalances in the instrument (not caused by filters) can complicate the data analysis. Consequently, for future, higher precision instrumentation, further investigation is required on any thermal imbalances embedded in such polymer-based filters. Particularly, in this paper the heating of polymers when operating at cryogenic temperature in space will be studied. Such phenomenon is an important aspect of their functioning since the transient emission of unwanted thermal radiation may affect the scientific measurements. To assess this effect, a computer model was developed for polypropylene based filters and PTFE-based coatings. Specifically, a theoretical model of their thermal properties was created and used into a multi-physics simulation that accounts for conductive and radiative heating effects of large optical elements, the geometry of which was suggested by the large format array instruments designed for future space missions. It was found that in the simulated conditions, the filters temperature was characterized by a time-dependent behaviour, modulated by a small scale fluctuation. Moreover, it was noticed that thermalization was reached only when a low power input was present.

Public demand for preserving local open space.

Science.gov (United States)

Jeffrey D. Kline

2006-01-01

Increased development results in the loss of forest, farm, range, and other open space lands that contribute to the quality of life of U.S. residents. I describe an economic rationale for growing public support for preserving local open space, based the growing scarcity of open space lands. I test the rationale empirically by correlating the prevalence of open space...

Electric Boiler and Heat Pump Thermo-Electrical Models for Demand Side Management Analysis in Low Voltage Grids

DEFF Research Database (Denmark)

Diaz de Cerio Mendaza, Iker; Bak-Jensen, Birgitte; Chen, Zhe

2013-01-01

The last fifteen years many European countries have integrated large percentage of renewable energy on their electricity generation mix. In Denmark the 21.3% of the electricity consumed nowadays is produced by the wind, and it has planned to be the 50% by 2025. In order to front future challenges...... on the power system control and operation, created by this unstable way of generation, Demand Side Management turns to be a promising solution. The storage capacity from thermo-electric units, like electric boilers and heat pumps, allows operating them with certain freedom. Hence they can be employed under...... certain coordination, to actively respond to the power system fluctuations. The following paper presents two simple thermo-electrical models of an electrical boiler and an air-source CO2 heat pump system. The purpose is using them in low voltage grids analysis to assess their capacity and flexibility...

Frosting characteristics and heating performance of a direct-expansion solar-assisted heat pump for space heating under frosting conditions

International Nuclear Information System (INIS)

Huang, Wenzhu; Ji, Jie; Xu, Ning; Li, Guiqiang

2016-01-01

Highlights: • Frosting and heating performance of DX-SAHP under frosting conditions is investigated. • The conditions when DX-SAHP frosts are studied. • The frosting process is observed during 360 min of operating. • The effect of ambient temperature, relative humidity and solar irradiation is analyzed. - Abstract: Direct expansion solar-assisted heat pump system (DX-SAHP) is promising in energy saving applications, but the performance of DX-SAHP under frosting conditions is rarely reported in the published literatures. In this paper, a DX-SAHP system with bare solar collectors for space heating is designed and experimentally investigated in the enthalpy difference lab with a solar simulator. The system is tested under a range of frosting conditions, with the ambient temperatures from 7 °C to −3 °C, the relative humidities of 50%, 70% and 90% and the solar irradiances of 0 W/m"2, 100 W/m"2, 200 W/m"2 and 300 W/m"2. The conditions when the DX-SAHP system frosts are studied. Results show that solar irradiance as low as 100 W/m"2 can totally prevent frosting when the ambient temperature is above −3 °C and the relative humidity is 70%. Besides, the frosting process is observed to be slower than that of fin-and-tube heat exchangers. The evaporator is not seriously frosted and the system performance is not significantly influenced after 360 min of continuous operating. Moreover the effects of ambient parameters, including the ambient temperature and the relative humidity, especially solar irradiation, on the system performance are studied and analyzed. Solar irradiation can effectively prevent or retard frosting, and also improve the heating performance of the DX-SAHP system. The DX-SAHP system is proved to be applicable under frosting conditions.

The study of development of welded compact plate heat exchanger for high temperature and pressure

International Nuclear Information System (INIS)

Park, Jae Hong; Lim, Hyug; Kim, Jung Kyu; Cho, Sung Youl; Kwon, Oh Boong

2009-01-01

In view of space saving, the design of more compact heat exchangers is relatively important. Also, to meet the demand for saving energy and resources today, manufacturers are trying to enhance efficiency and reduce the size and weight of heat exchangers. Over the past decade, there has been tremendous advancement in the manufacturing technology of high efficiency heat exchangers. This has allowed the use of smaller and high performance heat exchangers. Consequently, the use of smaller and high performance heat exchanger becomes popular in the design of heat exchangers. Welded compact plate heat exchanger is used in high temperature and pressure. In the design of heat exchanger, it is necessary to understand the heat transfer characteristics, so performance data are provided to help design of this type heat exchanger.

Earliest Deadline Control of a Group of Heat Pumps with a Single Energy Source

Directory of Open Access Journals (Sweden)

Jiří Fink

2016-07-01

Full Text Available In this paper, we develop and investigate the optimal control of a group of 104 heat pumps and a central Combined Heat and Power unit (CHP. The heat pumps supply space heating and domestic hot water to households. Each house has a buffer for domestic hot water and a floor heating system for space heating. Electricity for the heat pumps is generated by a central CHP unit, which also provides thermal energy to a district heating system. The paper reviews recent smart grid control approaches for central and distributed levels. An online algorithm is described based on the earliest deadline first theory that can be used on the aggregator level to control the CHP and to give signals to the heat pump controllers if they should start or should wait. The central controller requires only a limited amount of privacy-insensitive information from the heat pump controllers about their deadlines, which the heat pump controllers calculate for themselves by model predictions. In this way, a robust heat pump and CHP control is obtained, which is able to minimize energy demand and results in the desired thermal comfort for the households. The simulations demonstrate fast computation times due to minor computational and communication overheads.

Study of a Two-Pipe Chilled Beam System for both Cooling and Heating of Office Buildings

DEFF Research Database (Denmark)

Gordnorouzi, Rouzbeh; Hultmark, Göran; Afshari, Alireza

Active chilled beam systems are used to provide heating and cooling in order to achieve comfortable thermal indoor climate. For heating and cooling applications, an active chilled beam has two water circuits comprising four pipes that supply warm and cold water respectively to the beam coil...... according to the space demand. Lindab Comfort A/S has introduced an active chilled beam system which has just one water circuit (two pipes) that is used for both heating and cooling. The concept is based on high temperature cooling and low temperature heating. In this study the energy saving potential...

Analysis and decrease of the energy demand of bioethanol-production by process integration

Energy Technology Data Exchange (ETDEWEB)

Pfeffer, Martin; Wukovits, Walter; Beckmann, Georg; Friedl, Anton [Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna (Austria)

2007-11-15

Process simulation was used to decrease the external heat demand during the production of bioethanol by integration in a network of facilities for heat and power generation. Models for bioethanol fermentation and purification process, the production of DDGS as well as production and utilization of biogas were developed to calculate the heat demand of bioethanol-production and the amount of heat and power generated from residues of the bioethanol process. Depending on the form of biogas utilization (CHP-plant, biogas fired boiler) and the capacity of the bioethanol plant, the conversion of stillage from the bioethanol process to biogas covers a considerable amount of the heat demand necessary for bioethanol-production and purification. (author)

Model for Determining Geographical Distribution of Heat Saving Potentials in Danish Building Stock

Directory of Open Access Journals (Sweden)

Stefan Petrovic

2014-02-01

Full Text Available Since the global oil crisis in the 1970s, Denmark has followed a path towards energy independency by continuously improving its energy efficiency and energy conservation. Energy efficiency was mainly tackled by introducing a high number of combined heat and power plants in the system, while energy conservation was predominantly approached by implementing heat saving measures. Today, with the goal of 100% renewable energy within the power and heat sector by the year 2035, reductions in energy demand for space heating and the preparation of domestic hot water remain at the top of the agenda in Denmark. A highly detailed model for determining heat demand, possible heat savings and associated costs in the Danish building stock is presented. Both scheduled and energy-saving renovations until year 2030 have been analyzed. The highly detailed GIS-based heat atlas for Denmark is used as a container for storing data about physical properties for 2.5 million buildings in Denmark. Consequently, the results of the analysis can be represented on a single building level. Under the assumption that buildings with the most profitable heat savings are renovated first, the consequences of heat savings for the economy and energy system have been quantified and geographically referenced. The possibilities for further improvements of the model and the application to other geographical regions have been discussed.

Solar space and water heating system at Stanford University Central Food Services Building. Final report

Energy Technology Data Exchange (ETDEWEB)

1980-05-01

This active hydronic domestic hot water and space heating system was 840 ft/sup 2/ of single-glazed, liquid, flat plate collectors and 1550 gal heat storage tanks. The following are discussed: energy conservation, design philosophy, operation, acceptance testing, performance data, collector selection, bidding, costs, economics, problems, and recommendations. An operation and maintenance manual and as-built drawings are included in appendices. (MHR)

Numerical Investigation of Floor Heating Systems in Low Energy Houses

DEFF Research Database (Denmark)

Weitzmann, Peter; Kragh, Jesper; Jensen, Claus Franceos

2002-01-01

In this paper an investigation of floor heating systems is performed with respect to heating demand and room temperature. Presently (2001) no commercially available building simulation programs that can be used to evaluate heating demand and thermal comfort in buildings with building integrated....... The model calculates heating demand, room temperatures, and thermal comfort parameters for a person in the room. 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 has been used to calculate heating demand and room temperature in a typical well insulated Danish single-family house with a heating demand of approximately 6000 kWh per year, for a 130 m² house. Two different types of floor heating systems...

Field measurement and estimate of gaseous and particle pollutant emissions from cooking and space heating processes in rural households, northern China

Science.gov (United States)

Chen, Yuanchen; Shen, Guofeng; Liu, Weijian; Du, Wei; Su, Shu; Duan, Yonghong; Lin, Nan; Zhuo, Shaojie; Wang, Xilong; Xing, Baoshan; Tao, Shu

2016-01-01

Pollutant emissions into outdoor air from cooking and space heating processes with various solid fuels were measured, and daily household emissions were estimated from the kitchen performance tests. The burning of honeycomb briquette had the lowest emission factors, while the use of wood produced the highest pollutants. Daily emissions from space heating were significantly higher than those from cooking, and the use of honeycomb briquette for cooking and raw coal chunk for space heating reduces 28%, 24% and 25% for CO, PM10 and PM2.5, compared to wood for cooking and peat for space heating. Much higher emissions were observed during the initial phase than the stable phase due to insufficient air supply and lower combustion temperature at the beginning of burning processes. However, more mass percent of fine particles formed in the later high temperature stable burning phase may increase potential inhalation exposure risks.

Greenhouse gas and energy analysis of substitute natural gas from biomass for space heat

International Nuclear Information System (INIS)

Pucker, Johanna; Zwart, Robin; Jungmeier, Gerfried

2012-01-01

In this paper, the greenhouse gas and energy balances of the production and use for space heating of substitute natural gas from biomass (bio-SNG) for space heat are analysed. These balances are compared to the use of natural gas and solid biomass as wood chips to provide the same service. The reduction of the greenhouse gas emissions (CO 2 -eq.) – carbon dioxide, methane and nitrous oxide – and of the fossil primary energy use is investigated in a life cycle assessment (LCA). This assessment was performed for nine systems for bio-SNG; three types of gasification technologies (O 2 -blown entrained flow, O 2 -blown circulating fluidised bed and air–steam indirect gasification) with three different types of feedstock (forest residues, miscanthus and short rotation forestry). The greenhouse gas analysis shows that forest residues using the air–steam indirect gasification technology result in the lowest greenhouse gas emissions (in CO 2 -eq. 32 kg MWh −1 of heat output). This combination results in 80% reduction of greenhouse gas emissions when compared to natural gas and a 29% reduction of greenhouse gases if the forest residues were converted to wood chips and combusted. The gasification technologies O 2 -blown entrained flow and O 2 -blown circulating fluidised bed gasification have higher greenhouse gas emissions that range between in CO 2 -eq. 41 to 75 kg MWh −1 of heat output depending on the feedstock. When comparing feedstocks in the bio-SNG systems, miscanthus had the highest greenhouse gas emissions bio-SNG systems producing in CO 2 -eq. 57–75 kg MWh −1 of heat output. Energy analysis shows that the total primary energy use is higher for bio-SNG systems (1.59–2.13 MWh MWh −1 of heat output) than for the reference systems (in 1.37–1.51 MWh MWh −1 of heat output). However, with bio-SNG the fossil primary energy consumption is reduced compared to natural gas. For example, fossil primary energy use is reduced by 92% when air�

Combined Space and Water Heating: Next Steps to Improved Performance

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, B. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Bohac, D. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Huelman, P. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States)

2016-07-13

A combined space- and water-heating (combi) system uses a high-efficiency direct-vent burner that eliminates safety issues associated with natural draft appliances. Past research with these systems shows that using condensing water heaters or boilers with hydronic air handling units can provide both space and water heating with efficiencies of 90% or higher. Improved controls have the potential to reduce complexity and improve upon the measured performance. This project demonstrates that controls can significantly benefit these first-generation systems. Laboratory tests and daily load/performance models showed that the set point temperature reset control produced a 2.1%–4.3% (20–40 therms/year) savings for storage and hybrid water heater combi systems operated in moderate-load homes. The full modulation control showed additional savings over set point control (in high-load homes almost doubling the savings: 4%–5% over the no-control case). At the time of installation the reset control can be implemented for $200–$400, which would provide paybacks of 6–25 years for low-load houses and 3–15 years for high-load houses. Full modulation implementation costs would be similar to the outdoor reset and would provide paybacks of 5-½–20 years for low-load houses and 2-½–10 years for high-load houses.

Demand side management for smart district heating

DEFF Research Database (Denmark)

Big, Oovidiu; Li, Hongwei; Svendsen, Svend

2016-01-01

between 25% and 35%. By making the light renovation, the heating system needs a minimum supply water temperature of 58ºC in order to cover the thermal comfort. Through extensive renovation, the supply water temperature could be reduced to 50ºC which makes it possible to transform the District Heating...... Temperature into Low Temperature. The building time constant for the extensive renovation is 86 hours which is double than a light building renovation and 53 hours higher than a non-renovated building. In the end of the paper is developed a formula which has the purpose to validate the results of virtual...... simulations. The relative percentage difference between the theoretical calculation and the virtual simulation results are between 2.5% and 17.5%....

Energy Systems Scenario Modelling and Long Term Forecasting of Hourly Electricity Demand

DEFF Research Database (Denmark)

Alberg Østergaard, Poul; Møller Andersen, Frits; Kwon, Pil Seok

2015-01-01

. The results show that even with a limited short term electric car fleet, these will have a significant effect on the energy system; the energy system’s ability to integrate wind power and the demand for condensing power generation capacity in the system. Charging patterns and flexibility have significant...... or inflexible electric vehicles and individual heat pumps, and in the long term it is investigated what the effects of changes in the load profiles due to changing weights of demand sectors are. The analyses are based on energy systems simulations using EnergyPLAN and demand forecasting using the Helena model...... effects on this. Likewise, individual heat pumps may affect the system operation if they are equipped with heat storages. The analyses also show that the long term changes in electricity demand curve profiles have little impact on the energy system performance. The flexibility given by heat pumps...

Regional allocation of biomass to U.S. energy demands under a portfolio of policy scenarios.

Science.gov (United States)

Mullins, Kimberley A; Venkatesh, Aranya; Nagengast, Amy L; Kocoloski, Matt

2014-01-01

The potential for widespread use of domestically available energy resources, in conjunction with climate change concerns, suggest that biomass may be an essential component of U.S. energy systems in the near future. Cellulosic biomass in particular is anticipated to be used in increasing quantities because of policy efforts, such as federal renewable fuel standards and state renewable portfolio standards. Unfortunately, these independently designed biomass policies do not account for the fact that cellulosic biomass can equally be used for different, competing energy demands. An integrated assessment of multiple feedstocks, energy demands, and system costs is critical for making optimal decisions about a unified biomass energy strategy. This study develops a spatially explicit, best-use framework to optimally allocate cellulosic biomass feedstocks to energy demands in transportation, electricity, and residential heating sectors, while minimizing total system costs and tracking greenhouse gas emissions. Comparing biomass usage across three climate policy scenarios suggests that biomass used for space heating is a low cost emissions reduction option, while biomass for liquid fuel or for electricity becomes attractive only as emissions reduction targets or carbon prices increase. Regardless of the policy approach, study results make a strong case for national and regional coordination in policy design and compliance pathways.

Effect of Ducted HPWH on Space-Conditioning and Water Heating Energy Use -- Central Florida Lab Home

Energy Technology Data Exchange (ETDEWEB)

Colon, Carlos [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Martin, Eric [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Parker, Danny [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States)

2016-11-01

The purpose of this research is to investigate the impact of ducted heat pump water heaters (HPWHs) on space conditioning and water heating energy use in residential applications. Two identical HPWHs, each of 60 gallon capacity were tested side by side at the Flexible Residential Test facility (FRTF) laboratories of the Florida Solar Energy Center (FSEC) campus in Cocoa, Florida. The water heating experiments were run in each test house from July 2014 until February 2015.

Electric radiant heating or, why are plumbers getting our work?

Energy Technology Data Exchange (ETDEWEB)

Lemieux, G. [Britech, Toronto, ON (Canada)

2009-02-15

Electric radiant heating (ERH) technologies are now being installed in floors as a means of reducing heating costs. The radiant installations have seen a large increase in sales over the last decade, and are now being used in commercial applications. Sales of hydronic ERH systems have increased by 24 per cent over the last year. ERH systems are energy efficient and do not cause drafts. The systems consist of resistant heating cables installed within the floors of a room. The cables are supplied as loose cables and tracks with predetermined spacings or rugged, heavier cable that can be stapled onto wooden subfloors. Program temperature setbacks can be applied on a room-by-room basis. Electric thermal storage systems allow building owners to store heat in the floors and are ideal for use in combination with time-of-use electric metering. Some electric utilities are now promoting the use of electric thermal storage in order to reduce demand during peak times. Thermostats used with the systems should have floor sensors and ambient air sensors to control space heating in conjunction with the floor sensor. It was concluded that electrical contractors who gain knowledge in the application and installation of the systems will tap into a growing revenue stream. 5 figs.

Electric radiant heating or, why are plumbers getting our work?

International Nuclear Information System (INIS)

Lemieux, G.

2009-01-01

Electric radiant heating (ERH) technologies are now being installed in floors as a means of reducing heating costs. The radiant installations have seen a large increase in sales over the last decade, and are now being used in commercial applications. Sales of hydronic ERH systems have increased by 24 per cent over the last year. ERH systems are energy efficient and do not cause drafts. The systems consist of resistant heating cables installed within the floors of a room. The cables are supplied as loose cables and tracks with predetermined spacings or rugged, heavier cable that can be stapled onto wooden subfloors. Program temperature setbacks can be applied on a room-by-room basis. Electric thermal storage systems allow building owners to store heat in the floors and are ideal for use in combination with time-of-use electric metering. Some electric utilities are now promoting the use of electric thermal storage in order to reduce demand during peak times. Thermostats used with the systems should have floor sensors and ambient air sensors to control space heating in conjunction with the floor sensor. It was concluded that electrical contractors who gain knowledge in the application and installation of the systems will tap into a growing revenue stream. 5 figs

Dry heat tolerance of the dry colony in Nostoc sp. HK-01 for useful usage in space agriculture

Science.gov (United States)

Kimura, Shunta; Tomita-Yokotani, Kaori; Yamashita, Masamichi; Sato, Seigo; Katoh, Hiroshi

Space agriculture producing foods is important as one of approach for space habitation. Nostoc sp. HK-01 is one of terrestrial cyanobacterium having a high dry tolerance and it has several ability, photosynthesis, nitrogen fixation and usefulness as a food, it is thought that it can be used for space agriculture. Besides, a study on each tolerance predicted at the time of introduction to space agriculture is necessary. Therefore, as one of the tolerance that are intended to space environment, dry heat ( 100(°) C, 10 h ) tolerance of dry colony in Nostoc sp. HK-01 has been investigated, but the detail function of them has not yet been elucidated. We focused on the extracellular polysaccharides ( EPS ) having the various tolerance, desiccation, low temperature, NaCl, and heavy particle beam. We will consider the function and useful usage of this cyanobacterum in space agriculture after the consideration of the results of contribution of the possibility that EPS improves dry heat tolerance under a dry condition.

Assessment of CFD Hypersonic Turbulent Heating Rates for Space Shuttle Orbiter

Science.gov (United States)

Wood, William A.; Oliver, A. Brandon

2011-01-01

Turbulent CFD codes are assessed for the prediction of convective heat transfer rates at turbulent, hypersonic conditions. Algebraic turbulence models are used within the DPLR and LAURA CFD codes. The benchmark heat transfer rates are derived from thermocouple measurements of the Space Shuttle orbiter Discovery windward tiles during the STS-119 and STS-128 entries. The thermocouples were located underneath the reaction-cured glass coating on the thermal protection tiles. Boundary layer transition flight experiments conducted during both of those entries promoted turbulent flow at unusually high Mach numbers, with the present analysis considering Mach 10{15. Similar prior comparisons of CFD predictions directly to the flight temperature measurements were unsatisfactory, showing diverging trends between prediction and measurement for Mach numbers greater than 11. In the prior work, surface temperatures and convective heat transfer rates had been assumed to be in radiative equilibrium. The present work employs a one-dimensional time-accurate conduction analysis to relate measured temperatures to surface heat transfer rates, removing heat soak lag from the flight data, in order to better assess the predictive accuracy of the numerical models. The turbulent CFD shows good agreement for turbulent fuselage flow up to Mach 13. But on the wing in the wake of the boundary layer trip, the inclusion of tile conduction effects does not explain the prior observed discrepancy in trends between simulation and experiment; the flight heat transfer measurements are roughly constant over Mach 11-15, versus an increasing trend with Mach number from the CFD.

Reducing residential solid fuel combustion through electrified space heating leads to substantial air quality, health and climate benefits in China's Beijing-Tianjin-Hebei region

Science.gov (United States)

Yang, J.; Mauzerall, D. L.

2017-12-01

During periods of high pollution in winter, household space heating can contribute more than half of PM2.5 concentrations in China's Beijing-Tianjin-Hebei (BTH) region. The majority of rural households and some urban households in the region still heat with small stoves and solid fuels such as raw coal, coal briquettes and biomass. Thus, reducing emissions from residential space heating has become a top priority of the Chinese government's air pollution mitigation plan. Electrified space heating is a promising alternative to solid fuel. However, there is little analysis of the air quality and climate implications of choosing various electrified heating devices and utilizing different electricity sources. Here we conduct an integrated assessment of the air quality, human health and climate implications of various electrified heating scenarios in the BTH region using the Weather Research and Forecasting model with Chemistry. We use the Multi-resolution Emission Inventory for China for the year 2012 as our base case and design two electrification scenarios in which either direct resistance heaters or air source heat pumps are installed to replace all household heating stoves. We initially assume all electrified heating devices use electricity from supercritical coal-fired power plants. We find that installing air source heat pumps reduces CO2 emissions and premature deaths due to PM2.5 pollution more than resistance heaters, relative to the base case. The increased health and climate benefits of heat pumps occur because they have a higher heat conversion efficiency and thus require less electricity for space heating than resistance heaters. We also find that with the same heat pump installation, a hybrid electricity source (40% of the electricity generated from renewable sources and the rest from coal) further reduces both CO2 emissions and premature deaths than using electricity only from coal. Our study demonstrates the air pollution and CO2 mitigation potential and

Renewable Heating And Cooling

Science.gov (United States)

Renewable heating and cooling is a set of alternative resources and technologies that can be used in place of conventional heating and cooling technologies for common applications such as water heating, space heating, space cooling and process heat.

Adaptive neuro-fuzzy based inferential sensor model for estimating the average air temperature in space heating systems

Energy Technology Data Exchange (ETDEWEB)

Jassar, S.; Zhao, L. [Department of Electrical and Computer Engineering, Ryerson University, 350 Victoria Street, Toronto, ON (Canada); Liao, Z. [Department of Architectural Science, Ryerson University (Canada)

2009-08-15

The heating systems are conventionally controlled by open-loop control systems because of the absence of practical methods for estimating average air temperature in the built environment. An inferential sensor model, based on adaptive neuro-fuzzy inference system modeling, for estimating the average air temperature in multi-zone space heating systems is developed. This modeling technique has the advantage of expert knowledge of fuzzy inference systems (FISs) and learning capability of artificial neural networks (ANNs). A hybrid learning algorithm, which combines the least-square method and the back-propagation algorithm, is used to identify the parameters of the network. This paper describes an adaptive network based inferential sensor that can be used to design closed-loop control for space heating systems. The research aims to improve the overall performance of heating systems, in terms of energy efficiency and thermal comfort. The average air temperature results estimated by using the developed model are strongly in agreement with the experimental results. (author)

Automatic heating control system

Energy Technology Data Exchange (ETDEWEB)

Whittle, A.J.

1989-11-15

A heating control system for buildings comprises at least one heater incorporating heat storage means, a first sensor for detecting temperature within the building, means for setting a demand temperature, a second sensor for detecting outside temperature, a timer, and means for determining the switch on time of the heat storage means on the basis of the demand temperature and the internal and external temperatures. The system may additionally base the switch on time of the storage heater(s) on the heating and cooling rates of the building (as determined from the sensed temperatures); or on the anticipated daytime temperature (determined from the sensed night time temperature). (author).

Geothermal heat potential - the source for heating greenhouses in Southestern Europe

Directory of Open Access Journals (Sweden)

Urbancl Danijela

2016-01-01

Full Text Available The paper presents economically evaluated solutions for heating greenhouses with geothermal potential, if the same greenhouse is placed in two different locations in Southeastern Europe, one in Slovenia and the other in Serbia. The direct geothermal water exploitation using heat exchangers is presented and the remaining heat potential of already used geothermal water is exploited using high temperature heat pumps. Energy demands for heating greenhouses are calculated considering climatic parameters of both locations. Furthermore, different constructions materials are taken into account, and energy demands are evaluated if the same greenhouse is made of 4 mm toughened single glass, double insulated glass or polycarbonate plates. The results show that the geothermal energy usage is economically feasible in both locations, because payback periods are in range from two to almost eight years for different scenarios.

Effect of Ducted HPWH on Space-Conditioning and Water Heating Energy Use -- Central Florida Lab Home

Energy Technology Data Exchange (ETDEWEB)

Colon, Carlos [Florida Solar Energy Center, Cocoa, FL (United States); Martin, Eric [Florida Solar Energy Center, Cocoa, FL (United States); Parker, Danny [Florida Solar Energy Center, Cocoa, FL (United States)

2016-11-01

The purpose of this research is to investigate the impact of ducted heat pump water heaters (HPWH's) on space conditioning and water heating energy use in residential applications. Two identical HPWH's, each of 60 gallon capacity were tested side by side at the Flexible Residential Test facility (FRTF) laboratories of the Florida Solar Energy Center (FSEC) campus in Cocoa, Florida. The water heating experiments were run in each test house from July 2014 until February 2015.

Heating of a fully saturated darcian half-space: Pressure generation, fluid expulsion, and phase change

Science.gov (United States)

Delaney, P.

1984-01-01

Analytical solutions are developed for the pressurization, expansion, and flow of one- and two-phase liquids during heating of fully saturated and hydraulically open Darcian half-spaces subjected to a step rise in temperature at its surface. For silicate materials, advective transfer is commonly unimportant in the liquid region; this is not always the case in the vapor region. Volume change is commonly more important than heat of vaporization in determining the position of the liquid-vapor interface, assuring that the temperatures cannot be determined independently of pressures. Pressure increases reach a maximum near the leading edge of the thermal front and penetrate well into the isothermal region of the body. Mass flux is insensitive to the hydraulic properties of the half-space. ?? 1984.

Lunar Heat Flux Measurements Enabled by a Microwave Radiometer Aboard the Deep Space Gateway

Science.gov (United States)

Siegler, M.; Ruf, C.; Putzig, N.; Morgan, G.; Hayne, P.; Paige, D.; Nagihara, S.; Weber, R.

2018-02-01

We would like to present a concept to use the Deep Space Gateway as a platform for constraining the geothermal heat production, surface, and near-surface rocks, and dielectric properties of the Moon from orbit with passive microwave radiometery.

Flexible demand in the GB domestic electricity sector in 2030

International Nuclear Information System (INIS)

Drysdale, Brian; Wu, Jianzhong; Jenkins, Nick

2015-01-01

Highlights: • Annual domestic demand by category and daily flexible load profiles are shown to 2030. • Valuable flexible demand requires loads to be identifiable, accessible, and useful. • The extent of flexible demand varies significantly on a diurnal and seasonal basis. • Barriers to accessing domestic demand include multiple low value loads and apathy. • Existing market structure a barrier to fully rewarding individual load flexibility. - Abstract: In order to meet greenhouse gas emissions targets the Great Britain (GB) future electricity supply will include a higher fraction of non-dispatchable generation, increasing opportunities for demand side management to maintain a supply/demand balance. This paper examines the extent of flexible domestic demand (FDD) in GB, its usefulness in system balancing and appropriate incentives to encourage consumers to participate. FDD, classified as electric space and water heating (ESWH), and cold and wet appliances, amounts to 59 TW h in 2012 (113 TW h total domestic demand) and is calculated to increase to 67 TW h in 2030. Summer and winter daily load profiles for flexible loads show significant seasonal and diurnal variations in the total flexible load and between load categories. Low levels of reflective consumer engagement with electricity consumption and a resistance to automation present barriers to effective access to FDD. A value of £1.97/household/year has been calculated for cold appliance loads used for frequency response in 2030, using 2013 market rates. The introduction of smart meters in GB by 2020 will allow access to FDD for system balancing. The low commercial value of individual domestic loads increases the attractiveness of non-financial incentives to fully exploit FDD. It was shown that appliance loads have different characteristics which can contribute to an efficient power system in different ways

Effects of heat and electricity saving measures in district-heated multistory residential buildings

International Nuclear Information System (INIS)

Truong, Nguyen Le; Dodoo, Ambrose; Gustavsson, Leif

2014-01-01

Highlights: • We analyzed the potential for energy savings in district heated buildings. • Measures that reduce more peak load production give higher primary energy savings. • Efficient appliances increase heat demand but give net primary energy savings. • Efficient appliances give the largest net primary energy savings. - Abstract: The effects of heat and electricity saving measures in district-heated buildings can be complex because these depend not only on how energy is used on the demand side but also on how energy is provided from the supply side. In this study, we analyze the effects of heat and electricity saving measures in multistory concrete-framed and wood-framed versions of an existing district-heated building and examine the impacts of the reduced energy demand on different district heat (DH) production configurations. The energy saving measures considered are for domestic hot water reduction, building thermal envelope improvement, ventilation heat recovery (VHR), and household electricity savings. Our analysis is based on a measured heat load profile of an existing DH production system in Växjö, Sweden. Based on the measured heat load profile, we model three minimum-cost DH production system using plausible environmental and socio-political scenarios. Then, we investigate the primary energy implications of the energy saving measures applied to the two versions of the existing building, taking into account the changed DH demand, changed cogenerated electricity, and changed electricity use due to heat and electricity saving measures. Our results show that the difference between the final and primary energy savings of the concrete-framed and wood-framed versions of the case-study building is minor. The primary energy efficiency of the energy saving measures depends on the type of measure and on the composition of the DH production system. Of the various energy saving measures explored, electricity savings give the highest primary energy savings

Spray cooling heat transfer: Technology overview and assessment of future challenges for micro-gravity application

International Nuclear Information System (INIS)

Silk, Eric A.; Golliher, Eric L.; Paneer Selvam, R.

2008-01-01

Advanced on-board flight systems for future NASA space exploration programs consist of components such as laser-diode arrays (LDA's) and multi-chip modules (MCM's). Thermal management of these systems require high heat flux cooling capability (≥100 W/cm 2 ), tight temperature control (approx. ±2 deg. C), reliable start-up (on demand) and long term stability. Traditional multiphase thermal control technologies for space flight (e.g., loop heat pipes, capillary pumped loops, etc.) satisfy the temperature control, start-up and stability requirements, but their heat flux removal capabilities are limited. Spray cooling can provide high heat fluxes in excess of 100 W/cm 2 using fluorinerts and over 1000 W/cm 2 with water while allowing tight temperature control at low coolant fluid flow rates. Spray cooling has been flight proven in an open loop configuration through the Space shuttle's flash evaporator system (FES). However, several closed system issues require investigation to further advance the technology to a technology readiness level (TRL) appropriate for closed system space flight application. This paper provides a discussion of the current status of spray cooling technology as well as NASA's goals, current direction, and challenges associated with the implementation and practice of this technology in the micro-gravity environment

Performance analysis of a soil-based thermal energy storage system using solar-driven air-source heat pump for Danish buildings sector

DEFF Research Database (Denmark)

Jradi, M.; Veje, C.; Jørgensen, B. N.

2017-01-01

and the economic and environmental aspects. However, the intermittent nature of solar energy and the lack of high solar radiation intensities in various climates favour the use of various energy storage techniques to eliminate the discrepancy between energy supply and demand. The current work presents an analysis......, Denmark, in addition to charging the soil storage medium in summer months when excess electric power is generated. The stored heat is discharged in December and January to provide the space heating and domestic hot water demands of the residential project without the utilization of an external heating...... losses and the surrounding soil temperature variation throughout the year. It was found that the overall system heating coefficient of performance is around 4.76, where the reported energetic efficiency is 5.88% for the standalone PV system, 19.1% for the combined PV-ASHP system, and 22...

Heat exchanger optimization of a closed Brayton cycle for nuclear space propulsion

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Guilherme B.; Guimaraes, Lamartine N.F.; Braz Filho, Francisco A., E-mail: gbribeiro@ieav.cta.br, E-mail: guimarae@ieav.cta.br, E-mail: braz@ieav.cta.br [Instituto de Estudos Avancados (IEAV), Sao Jose dos Campos, SP (Brazil). Divisao de Energia Nuclear

2015-07-01

Nuclear power systems turned to space electric propulsion differs strongly from usual ground-based power systems regarding the importance of overall size and weight. For propulsion power systems, weight and efficiency are essential drivers that should be managed during conception phase. Considering that, this paper aims the development of a thermal model of a closed Brayton cycle that applies the thermal conductance of heat exchangers in order to predict the energy conversion performance. The centrifugal-flow turbine and compressor characterization were achieved using algebraic equations from literature data. The binary mixture of He-Xe with molecular weight of 40 g/mole is applied and the impact of heat exchanger optimization in thermodynamic irreversibilities is evaluated in this paper. (author)

Heat exchanger optimization of a closed Brayton cycle for nuclear space propulsion

International Nuclear Information System (INIS)

Ribeiro, Guilherme B.; Guimaraes, Lamartine N.F.; Braz Filho, Francisco A.

2015-01-01

Nuclear power systems turned to space electric propulsion differs strongly from usual ground-based power systems regarding the importance of overall size and weight. For propulsion power systems, weight and efficiency are essential drivers that should be managed during conception phase. Considering that, this paper aims the development of a thermal model of a closed Brayton cycle that applies the thermal conductance of heat exchangers in order to predict the energy conversion performance. The centrifugal-flow turbine and compressor characterization were achieved using algebraic equations from literature data. The binary mixture of He-Xe with molecular weight of 40 g/mole is applied and the impact of heat exchanger optimization in thermodynamic irreversibilities is evaluated in this paper. (author)

Thermal energy storage with geothermal triplet for space heating and cooling

Science.gov (United States)

Bloemendal, Martin; Hartog, Niels

2017-04-01

Many governmental organizations and private companies have set high targets in avoiding CO2 emissions and reducing energy (Kamp, 2015; Ministry-of-Economic-affairs, 2016). ATES systems use groundwater wells to overcome the discrepancy in time between the availability of heat (during summer) and the demand for heat (during winter). Aquifer Thermal Energy Storage is an increasingly popular technique; currently over 2000 ATES systems are operational in the Netherlands (Graaf et al., 2016). High temperature ATES may help to improve performance of these conventional ATES systems. ATES systems use heat pumps to get the stored heat to the required temperature for heating of around 40-50°C and to produce the cold water for cooling in summer. These heat pumps need quite a lot of power to run; on average an ATES system produces 3-4 times less CO2 emission compared to conventional. Over 60% of those emission are accounted for by the heat pump (Dekker, 2016). This heat pump power consumption can be reduced by utilizing other sources of sustainable heat and cooling capacity for storage in the subsurface. At such operating temperatures the required storage temperatures do no longer match the return temperatures in the building systems. Therefore additional components and an additional well are required to increase the groundwater temperature in summer (e.g. solar collectors) and decrease it in winter (e.g. dry coolers). To prevent "pollution" of the warm and cold well return water from the building can be stored in a third well until weather conditions are suitable for producing the required storage temperature. Simulations and an economical evaluation show great potential for this type of aquifer thermal energy storage; economic performance is better than normal ATES while the emissions are reduce by a factor ten. At larger temperature differences, also the volume of groundwater required to pump around is much less, which causes an additional energy saving. Research now

Miniature Heat Pipes

Science.gov (United States)

1997-01-01

Small Business Innovation Research contracts from Goddard Space Flight Center to Thermacore Inc. have fostered the company work on devices tagged "heat pipes" for space application. To control the extreme temperature ranges in space, heat pipes are important to spacecraft. The problem was to maintain an 8-watt central processing unit (CPU) at less than 90 C in a notebook computer using no power, with very little space available and without using forced convection. Thermacore's answer was in the design of a powder metal wick that transfers CPU heat from a tightly confined spot to an area near available air flow. The heat pipe technology permits a notebook computer to be operated in any position without loss of performance. Miniature heat pipe technology has successfully been applied, such as in Pentium Processor notebook computers. The company expects its heat pipes to accommodate desktop computers as well. Cellular phones, camcorders, and other hand-held electronics are forsible applications for heat pipes.

District heating from coal cures Germany's oil phobia

Energy Technology Data Exchange (ETDEWEB)

Cooper, G.

1982-04-30

Germany's firm commitment to district heating, energy conservation and renewable energy was the most striking impression to emerge from this year's Hanover Fair. Despite the present low price of oil, industry and government are resolved to reduce the country's dependence on this fuel. Although oil now accounts for only 44 per cent of German's total energy consumption, compared with 55 per cent in 1972, price rises and economic stagnation mean that its value is now equivalent to some 20 per cent of the country's exports compared with just 6 per cent in 1972. Space and process heating are the biggest oil users. District heating schemes, heat pumps and waste-heat recovery are all being vigorously promoted to reduce the oil demand from these sectors. A recent study by the German Ministry of Research and Technology estimates that 25 per cent of all domestic heat could be delivered economically by district heating, some three times the present installed capacity.

Technology Roadmaps: Solar Heating and Cooling

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-09-06

The solar heating and cooling (SHC) roadmap outlines a pathway for solar energy to supply almost one sixth (18 EJ) of the world's total energy use for both heating and cooling by 2050. This would save some 800 megatonnes of carbon dioxide (CO2) emissions per year; more than the total CO2 emissions in Germany in 2009. While solar heating and cooling today makes a modest contribution to world energy demand, the roadmap envisages that if concerted action is taken by governments and industry, solar energy could annually produce more than 16% of total final energy use for low temperature heat and nearly 17% for cooling. Given that global energy demand for heat represents almost half of the world's final energy use -- more than the combined global demand for electricity and transport -- solar heat can make a significant contribution in both tackling climate change and strengthening energy security.

Technology Roadmaps: Solar Heating and Cooling

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-07-01

The solar heating and cooling (SHC) roadmap outlines a pathway for solar energy to supply almost one sixth (18 EJ) of the world’s total energy use for both heating and cooling by 2050. This would save some 800 megatonnes of carbon dioxide (CO2) emissions per year; more than the total CO2 emissions in Germany in 2009. While solar heating and cooling today makes a modest contribution to world energy demand, the roadmap envisages that if concerted action is taken by governments and industry, solar energy could annually produce more than 16% of total final energy use for low temperature heat and nearly 17% for cooling. Given that global energy demand for heat represents almost half of the world’s final energy use – more than the combined global demand for electricity and transport – solar heat can make a significant contribution in both tackling climate change and strengthening energy security.

A techno-economic comparison of ground-coupled and air-coupled heat pump system for space cooling

Energy Technology Data Exchange (ETDEWEB)

Esen, Hikmet; Esen, Mehmet [Department of Mechanical Education, Faculty of Technical Education, University of Firat, 23119 Elazig (Turkey); Inalli, Mustafa [Department of Mechanical Engineering, Faculty of Engineering, University of Firat, 23119 Elazig (Turkey)

2007-05-15

This paper reports a techno-economic comparison between a ground-coupled heat pump (GCHP) system and an air-coupled heat pump (ACHP) system. The systems connected to a test room in Firat University, Elazig (38.41{sup o}N, 39.14{sup o}E), Turkey, were designed and constructed for space cooling. The performances of the GCHP and the ACHP system were experimentally determined. The experimental results were obtained from June to September in cooling season of 2004. The average cooling performance coefficients (COP{sub sys}) of the GCHP system for horizontal ground heat exchanger (HGHE) in the different trenches, at 1 and 2m depths, were obtained to be 3.85 and 4.26, respectively and the COP{sub sys} of the ACHP system was determined to be 3.17. The test results indicate that system parameters can have an important effect on performance, and that GCHP systems are economically preferable to ACHP systems for the purpose of space cooling. (author)

Improvement of Thrust Bearing Calculation Considering the Convectional Heating within the Space between the Pads

OpenAIRE

Monika Chmielowiec-Jablczyk; Andreas Schubert; Christian Kraft; Hubert Schwarze; Michal Wodtke; Michal Wasilczuk

2018-01-01

A modern thrust bearing tool is used to estimate the behavior of tilting pad thrust bearings not only in the oil film between pad and rotating collar, but also in the space between the pads. The oil flow in the space significantly influences the oil film inlet temperature and the heating of pad and collar. For that reason, it is necessary to define an oil mixing model for the space between the pads. In the bearing tool, the solutions of the Reynolds equation including a cavitation model, the ...

Developments to an existing city-wide district energy network – Part I: Identification of potential expansions using heat mapping

International Nuclear Information System (INIS)

Finney, Karen N.; Sharifi, Vida N.; Swithenbank, Jim; Nolan, Andy; White, Simon; Ogden, Simon

2012-01-01

Highlights: ► Domestic heat loads here are vast: 1.5 GW for current areas and 35 MW for new homes. ► Other heat sinks in Sheffield had a heat load/demand of 54 MW. ► New heat sources could provide additional heat to the network to meet these demands. ► Six ‘heat zones’ for possible district energy network expansions were identified. ► The infrastructure was planned, including energy centres, back-ups and heat pipes. - Abstract: District heating can provide cost-effective and low-carbon energy to local populations, such as space heating in winter and year-round hot/cold water; this is also associated with electricity generation in combined-heat-and-power systems. Although this is currently rare in the UK, many legislative policies, including the Renewable Heat Incentive, aim to increase the amount of energy from such sources; including new installations, as well as extending/upgrading existing distributed energy schemes. Sheffield already has an award-winning district energy network, incorporating city-wide heat distribution. This paper aimed to demonstrate the opportunities for expansions to this through geographical information systems software modelling for an in-depth analysis of the heat demands in the city. ‘Heat maps’ were produced, locating existing and emerging heat sources and sinks. Heat loads (industrial, commercial, educational, health care, council and leisure facilities/complex) total 53 MW, with existing residential areas accounting for ∼1500 MW and new housing developments potentially adding a further 35 MW in the future. A number of current and emerging heat sources were also discovered – potential suppliers of thermal energy to the above-defined heat sinks. From these, six ‘heat zones’ where an expansion to the existing network could be possible were identified and the infrastructure planned for each development.

Demand response in energy markets

International Nuclear Information System (INIS)

Skytte, K.; Birk Mortensen, J.

2004-11-01

Improving the ability of energy demand to respond to wholesale prices during critical periods of the spot market can reduce the total costs of reliably meeting demand, and the level and volatility of the prices. This fact has lead to a growing interest in the short-run demand response. There has especially been a growing interest in the electricity market where peak-load periods with high spot prices and occasional local blackouts have recently been seen. Market concentration at the supply side can result in even higher peak-load prices. Demand response by shifting demand from peak to base-load periods can counteract the market power in the peak-load. However, demand response has so far been modest since the current short-term price elasticity seems to be small. This is also the case for related markets, for example, green certificates where the demand is determined as a percentage of the power demand, or for heat and natural gas markets. This raises a number of interesting research issues: 1) Demand response in different energy markets, 2) Estimation of price elasticity and flexibility, 3) Stimulation of demand response, 4) Regulation, policy and modelling aspects, 5) Demand response and market power at the supply side, 6) Energy security of supply, 7) Demand response in forward, spot, ancillary service, balance and capacity markets, 8) Demand response in deviated markets, e.g., emission, futures, and green certificate markets, 9) Value of increased demand response, 10) Flexible households. (BA)

Evaluation of climate change impacts on energy demand

DEFF Research Database (Denmark)

Taseska, Verica; Markovska, Natasa; Callaway, John M.

2012-01-01

change and the energy demand in Macedonia. The analyses are conducted using the MARKAL (MARKet ALlocation)-Macedonia model, with a focus on energy demand in commercial and residential sectors (mainly for heating and cooling). Three different cases are developed: 1) Base Case, which gives the optimal...... electricity production mix, taking into account country’s development plans (without climate change); 2) Climate Change Damage Case, which introduces the climate changes by adjusting the heating and cooling degree days inputs, consistent with the existing national climate scenarios; and 3) Climate Change...... Adaptation Case, in which the optimal electricity generation mix is determined by allowing for endogenous capacity adjustments in the model. This modeling exercise will identify the changes in the energy demand and in electricity generation mix in the Adaptation Case, as well as climate change damages...

Renewable energy in the heating sector in Austria with particular reference to the region of Upper Austria

International Nuclear Information System (INIS)

Kranzl, Lukas; Kalt, Gerald; Müller, Andreas; Hummel, Marcus; Egger, Christiane; Öhlinger, Christine; Dell, Gerhard

2013-01-01

The heating sector has been neglected in energy policies for quite some time, especially on the European level. Only recently, with the implementation of the European directive 2009/28/EC the sector has gained higher attention. The objective of this paper is to provide an overview of the heat market in Austria and of the current status and future prospects of renewable energy in the heat sector (RES-H) up to 2030. Despite the growing energy demand, the share of renewable energy in the total energy demand for space heating and hot water increased from about 20% in 1970 to about 34% in 2008. This is mainly due to ambitious RES-H support instruments and regional policy targets. For example, the government of the region of Upper Austria has implemented a target of 100% RES-H share in the space heating and hot water sector until the year 2030. However, the National Renewable Energy Action Plan for 2020 foresees only moderate growth rates for RES-H compared to recent market growth and scenarios in literature. Due to the ambitious targets and support schemes of regional governments it seems likely that RES-H deployment could growstronger than stated in the action plan. - Highlights: ► Overview on Austrian heat sector and RES-H development. ► Growing RES-H market mainly due to regional promotion schemes. ► Austrian NREAP foresees only moderate growth of RES-H up to 2020. ► Targets and policies on the regional level might lead to stronger RES-H deployment

Regulation and Measurement of the Heat Generated by Automatic Tooth Preparation in a Confined Space.

Science.gov (United States)

Yuan, Fusong; Zheng, Jianqiao; Sun, Yuchun; Wang, Yong; Lyu, Peijun

2017-06-01

The aim of this study was to assess and regulate heat generation in the dental pulp cavity and circumambient temperature around a tooth during laser ablation with a femtosecond laser in a confined space. The automatic tooth preparing technique is one of the traditional oral clinical technology innovations. In this technique, a robot controlled an ultrashort pulse laser to automatically complete the three-dimensional teeth preparing in a confined space. The temperature control is the main measure for protecting the tooth nerve. Ten tooth specimens were irradiated with a femtosecond laser controlled by a robot in a confined space to generate 10 teeth preparation. During the process, four thermocouple sensors were used to record the pulp cavity and circumambient environment temperatures with or without air cooling. A statistical analysis of the temperatures was performed between the conditions with and without air cooling (p heat generated in the pulp cavity was lower than the threshold for dental pulp damage. These results indicate that femtosecond laser ablation with air cooling might be an appropriate method for automatic tooth preparing.

Changes in the timing, length and heating degree days of the heating season in central heating zone of China

Science.gov (United States)

Shen, Xiangjin; Liu, Binhui

2016-01-01

Climate change affects the demand for energy consumption, especially for heating and cooling buildings. Using daily mean temperature (Tmean) data, this study analyzed the spatiotemporal changes of the starting date for heating (HS), ending date for heating (HE), length (HL) and heating degree day (HDD) of the heating season in central heating zone of China. Over China’s central heating zone, regional average HS has become later by 0.97 day per decade and HE has become earlier by 1.49 days per decade during 1960–2011, resulting in a decline of HL (−2.47 days/decade). Regional averaged HDD decreased significantly by 63.22 °C/decade, which implies a decreasing energy demand for heating over the central heating zone of China. Spatially, there are generally larger energy-saving rate in the south, due to low average HDD during the heating season. Over China’s central heating zone, Tmean had a greater effect on HL in warm localities and a greater effect on HDD in cold localities. We project that the sensitivity of HL (HDD) to temperature change will increase (decrease) in a warmer climate. These opposite sensitivities should be considered when we want to predict the effects of climate change on heating energy consumption in China in the future. PMID:27651063

The Roles of Teachers' Science Talk in Revealing Language Demands within Diverse Elementary School Classrooms: A Study of Teaching Heat and Temperature in Singapore

Science.gov (United States)

Seah, Lay Hoon; Yore, Larry D.

2017-01-01

This study of three science teachers' lessons on heat and temperature seeks to characterise classroom talk that highlighted the ways language is used and to examine the nature of the language demands revealed in constructing, negotiating, arguing and communicating science ideas. The transcripts from the entire instructional units for these…

Energy and exergy analysis of low temperature district heating network

DEFF Research Database (Denmark)

Li, Hongwei; Svendsen, Svend

2012-01-01

is designed to supply heating for 30 low energy detached residential houses. The network operational supply/return temperature is set as 55 °C/25 °C, which is in line with a pilot project carried out in Denmark. Two types of in-house substations are analyzed to supply the consumer domestic hot water demand...... energy/exergy losses and increase the quality match between the consumer heating demand and the district heating supply.......Low temperature district heating with reduced network supply and return temperature provides better match of the low quality building heating demand and the low quality heating supply from waste heat or renewable energy. In this paper, a hypothetical low temperature district heating network...

Greenhouse gas and energy analysis of substitute natural gas from biomass for space heat

Energy Technology Data Exchange (ETDEWEB)

Pucker, J.; Jungmeier, G. [JOANNEUM RESEARCH Forschungsgesellschaft mbH, RESOURCES - Institute for Water, Energy and Sustainability, Steyrergasse 17, 8010 Graz (Austria); Zwart, R. [Energy Research Centre of The Netherlands (ECN), Westerduinweg 3, 1755 LE Petten (Netherlands)

2012-03-15

In this paper, the greenhouse gas and energy balances of the production and use for space heating of substitute natural gas from biomass (bio-SNG) for space heat are analysed. These balances are compared to the use of natural gas and solid biomass as wood chips to provide the same service. The reduction of the greenhouse gas emissions (CO{sub 2}-eq.) - carbon dioxide, methane and nitrous oxide - and of the fossil primary energy use is investigated in a life cycle assessment (LCA). This assessment was performed for nine systems for bio-SNG; three types of gasification technologies (O{sub 2}-blown entrained flow, O{sub 2}-blown circulating fluidised bed and air-steam indirect gasification) with three different types of feedstock (forest residues, miscanthus and short rotation forestry). The greenhouse gas analysis shows that forest residues using the air-steam indirect gasification technology result in the lowest greenhouse gas emissions (in CO{sub 2}-eq. 32 kg MWh{sup -1} of heat output). This combination results in 80% reduction of greenhouse gas emissions when compared to natural gas and a 29% reduction of greenhouse gases if the forest residues were converted to wood chips and combusted. The gasification technologies O{sub 2}-blown entrained flow and O{sub 2}-blown circulating fluidised bed gasification have higher greenhouse gas emissions that range between in CO{sub 2}-eq. 41 to 75 kg MWh{sup -1} of heat output depending on the feedstock. When comparing feedstocks in the bio-SNG systems, miscanthus had the highest greenhouse gas emissions bio-SNG systems producing in CO2-eq. 57-75 kg MWh{sup -1} of heat output. Energy analysis shows that the total primary energy use is higher for bio-SNG systems (1.59-2.13 MWh MWh{sup -1} of heat output) than for the reference systems (in 1.37-1.51 MWh MWh{sup -1} of heat output). However, with bio-SNG the fossil primary energy consumption is reduced compared to natural gas. For example, fossil primary energy use is reduced by

Reducing cell-to-cell spacing for large-format lithium ion battery modules with aluminum or PCM heat sinks under failure conditions

International Nuclear Information System (INIS)

Coleman, Brittany; Ostanek, Jason; Heinzel, John

2016-01-01

Highlights: • Finite element analysis to evaluate heat sinks for large format li-ion batteries. • Solid metal heat sink and composite heat sink (metal filler and wax). • Transient simulations show response from rest to steady-state with normal load. • Transient simulations of two different failure modes were considered. • Significance of spacing, material properties, interface quality, and phase change. - Abstract: Thermal management is critical for large-scale, shipboard energy storage systems utilizing lithium-ion batteries. In recent years, there has been growing research in thermal management of lithium-ion battery modules. However, there is little information available on the minimum cell-to-cell spacing limits for indirect, liquid cooled modules when considering heat release during a single cell failure. For this purpose, a generic four-cell module was modeled using finite element analysis to determine the sensitivity of module temperatures to cell spacing. Additionally, the effects of different heat sink materials and interface qualities were investigated. Two materials were considered, a solid aluminum block and a metal/wax composite block. Simulations were run for three different transient load profiles. The first profile simulates sustained high rate operation where the system begins at rest and generates heat continuously until it reaches steady state. And, two failure mode simulations were conducted to investigate block performance during a slow and a fast exothermic reaction, respectively. Results indicate that composite materials can perform well under normal operation and provide some protection against single cell failure; although, for very compact designs, the amount of wax available to absorb heat is reduced and the effectiveness of the phase change material is diminished. The aluminum block design performed well under all conditions, and showed that heat generated during a failure is quickly dissipated to the coolant, even under the

Characterization of dynamic thermal control schemes and heat transfer pathways for incorporating variable emissivity electrochromic materials into a space suit heat rejection system

Science.gov (United States)

Massina, Christopher James

The feasibility of conducting long duration human spaceflight missions is largely dependent on the provision of consumables such as oxygen, water, and food. In addition to meeting crew metabolic needs, water sublimation has long served as the primary heat rejection mechanism in space suits during extravehicular activity (EVA). During a single eight hour EVA, approximately 3.6 kg (8 lbm) of water is lost from the current suit. Reducing the amount of expended water during EVA is a long standing goal of space suit life support systems designers; but to date, no alternate thermal control mechanism has demonstrated the ability to completely eliminate the loss. One proposed concept is to convert the majority of a space suit's surface area into a radiator such that the local environment can be used as a radiative thermal sink for rejecting heat without mass loss. Due to natural variations in both internal (metabolic) loads and external (environmental) sink temperatures, radiative transport must be actively modulated in order to maintain an acceptable thermal balance. Here, variable emissivity electrochromic devices are examined as the primary mechanism for enabling variable heat rejection. This dissertation focuses on theoretical and empirical evaluations performed to determine the feasibility of using a full suit, variable emissivity radiator architecture for space suit thermal control. Operational envelopes are described that show where a given environment and/or metabolic load combination may or may not be supported by the evaluated thermal architecture. Key integration considerations and guidelines include determining allowable thermal environments, defining skin-to-radiator heat transfer properties, and evaluating required electrochromic performance properties. Analysis also considered the impacts of dynamic environmental changes and the architecture's extensibility to EVA on the Martian surface. At the conclusion of this work, the full suit, variable emissivity

Refrigerated Warehouse Demand Response Strategy Guide

Energy Technology Data Exchange (ETDEWEB)

Scott, Doug [VaCom Technologies, San Luis Obispo, CA (United States); Castillo, Rafael [VaCom Technologies, San Luis Obispo, CA (United States); Larson, Kyle [VaCom Technologies, San Luis Obispo, CA (United States); Dobbs, Brian [VaCom Technologies, San Luis Obispo, CA (United States); Olsen, Daniel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2015-11-01

This guide summarizes demand response measures that can be implemented in refrigerated warehouses. In an appendix, it also addresses related energy efficiency opportunities. Reducing overall grid demand during peak periods and energy consumption has benefits for facility operators, grid operators, utility companies, and society. State wide demand response potential for the refrigerated warehouse sector in California is estimated to be over 22.1 Megawatts. Two categories of demand response strategies are described in this guide: load shifting and load shedding. Load shifting can be accomplished via pre-cooling, capacity limiting, and battery charger load management. Load shedding can be achieved by lighting reduction, demand defrost and defrost termination, infiltration reduction, and shutting down miscellaneous equipment. Estimation of the costs and benefits of demand response participation yields simple payback periods of 2-4 years. To improve demand response performance, it’s suggested to install air curtains and another form of infiltration barrier, such as a rollup door, for the passageways. Further modifications to increase efficiency of the refrigeration unit are also analyzed. A larger condenser can maintain the minimum saturated condensing temperature (SCT) for more hours of the day. Lowering the SCT reduces the compressor lift, which results in an overall increase in refrigeration system capacity and energy efficiency. Another way of saving energy in refrigerated warehouses is eliminating the use of under-floor resistance heaters. A more energy efficient alternative to resistance heaters is to utilize the heat that is being rejected from the condenser through a heat exchanger. These energy efficiency measures improve efficiency either by reducing the required electric energy input for the refrigeration system, by helping to curtail the refrigeration load on the system, or by reducing both the load and required energy input.

Solar/electric heating systems for the future energy system

DEFF Research Database (Denmark)

Furbo, Simon; Dannemand, Mark; Perers, Bengt

elements/heat pump, advanced heat storage tanks and advanced control systems. Heat is produced by solar collectors in sunny periods and by electrical heating elements/heat pump. The electrical heating elements/heat pump will be in operation in periods where the heat demand cannot be covered by solar energy....... The aim is to use the auxiliary heating units when the electricity price is low, e.g. due to large electricity production by wind turbines. The unit is equipped with an advanced control system where the control of the auxiliary heating is based on forecasts of the electricity price, the heat demand...

Effects of Heating on Teflon(Registered Trademark) FEP Thermal Control Material from the Hubble Space Telescope

Science.gov (United States)

deGroh, Kim; Gaier, James R.; Hall, Rachelle L.; Norris, Mary Jo; Espe, Matthew P.; Cato, Daveen R.

1999-01-01

Metallized Teflon(Registered Trademark) FEP (fluorinated ethylene propylene) thermal control material on the Hubble Space Telescope (HST) is degrading in the space environment. Teflon(Registered Trademark) FEP thermal control blankets (space-facing FEP) retrieved during the first servicing mission (SM1) were found to be embrittled on solar facing surfaces and contained microscopic cracks. During the second servicing mission (SM2) astronauts noticed that the FEP outer layer of the multi-layer insulation (MLI) covering the telescope was cracked in many locations around the telescope. Large cracks were observed on the light shield, forward shell and equipment bays. A tightly curled piece of cracked FEP from the light shield was retrieved during SM2 and was severely embrittled, as witnessed by ground testing. A Failure Review Board (FRB) was organized to determine the mechanism causing the MLI degradation. Density, x-ray crystallinity and solid state nuclear magnetic resonance (NMR) analyses of FEP retrieved during SM1 were inconsistent with results of FEP retrieved during SM2. Because the retrieved SM2 material curled while in space, it experienced a higher temperature extreme during thermal cycling, estimated at 200 C, than the SM1 material, estimated at 50 C. An investigation on the effects of heating pristine and FEP exposed on HST was therefore conducted. Samples of pristine. SM1, and SM2 FEP were heated to 200 C and evaluated for changes in density and morphology. Elevated temperature exposure was found to have a major impact on the density of the retrieved materials. Characterization of polymer morphology of as-received and heated FEP samples by NMR provided results that were consistent with the density results. These findings have provided insight to the damage mechanisms of FEP in the space environment.

Optimal dimensioning of low-energy district heating networks with operational planning

DEFF Research Database (Denmark)

Tol, Hakan; Svendsen, Svend

2012-01-01

in design stage resulted in satisfaction of heat demand of the house in low temperature operation. In this paper the operational planning of the low-energy DH systems was investigated to reduce the dimensions of the distribution network with consideration given both to current high-heat and future low......-heat demand situations. The operational planning was based on boosting (increasing) the supply temperature at peak-demand situations which occur rarely over a year period. Hence optimal pipe dimensions of low-energy DH systems were investigated based on the dynamic response of in-house heating systems...... of operational planning in comparison to DH network dimensioned according to high heat demand situation....

Achieving low return temperature for domestic hot water preparation by ultra-low-temperature district heating

DEFF Research Database (Denmark)

Yang, Xiaochen; Svendsen, Svend

2017-01-01

District heating (DH) is a cost-effective method of heat supply, especially to area with high heat density. Ultra-low-temperature district heating (ULTDH) is defined with supply temperature at 35-45 degrees C. It aims at making utmost use of the available low-temperature energy sources. In order...... to achieve high efficiency of the ULTDH system, the return temperature should be as low as possible. For the energy-efficient buildings in the future, it is feasible to use ULTDH to cover the space heating demand. However, considering the comfort and hygiene requirements of domestic hot water (DHW...... lower return temperature and higher efficiency for DHW supply, an innovative substation was devised, which replaced the bypass with an instantaneous heat exchanger and a micro electric storage tank. The energy performance of the proposed substation and the resulting benefits for the DH system...

Industrial excess heat for district heating in Denmark

DEFF Research Database (Denmark)

Bühler, Fabian; Petrovic, Stefan; Karlsson, Kenneth Bernard

2017-01-01

analyses excess heat sources from the industrial sector and how they could be used for district heating. This method first allocates excess heat to single production units by introducing and validating a new approach. Spatial analysis of the heat sources and consumers are then performed to evaluate...... the potential for using them for district heating. In this way the theoretical potential of using the excess heat for covering the heating demand of buildings is determined. Through the use of industry specific temperature profiles the heat usable directly or via heat pumps is further found. A sensitivity...... analysis investigates the impact of future energy efficiency measures in the industry, buildings and the district heating grid on the national potential. The results show that for the case study of Denmark, 1.36 TWh of district heat could be provided annually with industrial excess heat from thermal...

Development and preliminary assessment of the wall condensation heat transfer models for the SPACE code

International Nuclear Information System (INIS)

Park, Hyun Sik; Choi, Ki Yong; Moon, Sang Ki; Kim, Jung Woo; Kim, Kyung Doo

2009-01-01

The wall condensation heat transfer models are developed for the SPACE code and are assessed for various condensation conditions. Both default and alternative models were selected through an extensive literature survey. For a pure steam condensation, a maximum value among the Nusselt, Chato, and Shah's correlations is used in order to consider the geometric and turbulent effects. In the presence of non-condensable gases, the Colburn-Hougen's diffusion model was used as a default model and a non-iterative condensation model proposed by No and Park was selected as an alternative model. The wall condensation heat transfer models were assessed preliminarily by using arbitrary test conditions. Both wall condensation models could simulate the heat transfer coefficients and heat fluxes in the vertical, horizontal and turbulent conditions quite reasonably for a pure steam condensation. Both the default and alternative wall condensation models were also verified for the condensation heat transfer coefficient and heat flux in the presence of noncondensable gas. However, some improvements and further detailed verification are necessary for the condensation phenomena in the presence of noncondensable gas

Process for adapting a heat source and a thermal machine by temporary heat storage

International Nuclear Information System (INIS)

Cahn, R.P.; Nicholson, E.W.

1975-01-01

The process described is intended to ensure the efficient use of the heat from a nuclear reactor or from a furnace burning fossil fuel at constant power, and of a boiler in a power station comprising a multi-stage steam turbine, the steam extracted from the turbine being used for pre-heating the boiler feed water. This process is most flexible with a varying load. It includes the high temperature storage of the excess heat energy in a low vapor pressure storage liquid (hydrocarbon oils, molten salts or liquid metals) at atmospheric pressure when the demand is low; then, when the energy demand is at its height, the reduction of steam extraction from the turbine with simultaneous utilisation of the hot heat storage liquid for the various maintenance heating functions of the power station by heat exchange, so that the heat can expand totally in the turbine with generation of energy [fr

Cultural Ecosystem Services of Urban Green Spaces-Supply and Demand in The Densely Built-Up Areas. Poznan Old Town Case Study

Science.gov (United States)

Ponizy, Lidia; Majchrzak, Weronika; Zwierzchowska, Iwona

2017-12-01

The quality of life of big city dwellers depends on the use of green infrastructure. The idea of a compact city, opposed to urban sprawl, can lead to reduced access to green areas and increased demand for cultural services provided through urban green infrastructure. Considering the above, the aim of the paper was to identify the supply of and demand for cultural ecosystem services related to the urban green spaces in densely built-up urban areas. To find out how important the ability to use green areas for dwellers of the densely built-up areas is, the questionnaire interviews with the residents of the area of the Old Town of Poznan were conducted. Questions in the survey concerned the amount of green spaces and their availability, the way of use, types of activity, factors limiting the use and factors encouraging to visit green spaces and the motives for using green areas away from inhabitants’ place of residence. Respondents claim that there is not enough greenery, especially associated with housing and street side greenery; the amount of parks (which they use most) is slightly higher, in their opinion. Limitations that influence utilising green spaces concern both greenery itself (e.g. insufficient recreational infrastructure, neglected green areas) as well as respondent’s issues (e.g. lack of free time). Improvements to recreational infrastructure and more well-kept green spaces would encourage respondents to utilise it more often. Active participation of inhabitants in developing and maintaining their closest neighbourhood would allow to enlarge green spaces in housing areas and make them more customized to the residents’ needs and requirements in terms of functionality and aesthetic.

A study on experiment and numerical simulation of heat exchanger in heating furnace

Directory of Open Access Journals (Sweden)

Z. C. Lv

2018-01-01

Full Text Available In this paper, air preheater is used the research object and its heat transfer law is studied by experiment and numerical simulation. The experimental data showed that with the increases of inlet air velocity, the comprehensive heat transfer coefficient and heat transfer efficiency increase, but the temperature efficiency decreases and the resistance loss on the air side increases. The numerical simulation results showed that the larger the diameter of the tube, the better the heat transfer effect. When horizontal spacing in the range of 290 - 305 mm and longitudinal spacing is 70 - 90 mm, the heat transfer effect is best. The optimized heat exchanger structure is that diameter is 60 mm, horizontal spacing is 300 mm, longitudinal spacing is 90 mm. As the inlet air flow rate increases, the heat transfer efficiency increases, but the temperature efficiency decreases and the resistance loss on the air side increases.

Thermal energy storage for electricity-driven space heating in a day-ahead electricity market

DEFF Research Database (Denmark)

Pensini, Alessandro

2012-01-01

Thermal Energy Storage (TES) in a space heating (SH) application was investigated. The study aimed to determine the economic benefits of introducing TES into an electricity-driven SH system under a day-ahead electricity market. The performance of the TES was assessed by comparing the cost...... of electricity in a system with a TES unit to the case where no storage is in use and the entire heat requirement is fulfilled by purchasing electricity according to the actual load. The study had two goals: 1. Determining how the size – in terms of electricity input (Pmax) and energy capacity (Emax...

Thermal performance and heat transport in aquifer thermal energy storage

Science.gov (United States)

Sommer, W. T.; Doornenbal, P. J.; Drijver, B. C.; van Gaans, P. F. M.; Leusbrock, I.; Grotenhuis, J. T. C.; Rijnaarts, H. H. M.

2014-01-01

Aquifer thermal energy storage (ATES) is used for seasonal storage of large quantities of thermal energy. Due to the increasing demand for sustainable energy, the number of ATES systems has increased rapidly, which has raised questions on the effect of ATES systems on their surroundings as well as their thermal performance. Furthermore, the increasing density of systems generates concern regarding thermal interference between the wells of one system and between neighboring systems. An assessment is made of (1) the thermal storage performance, and (2) the heat transport around the wells of an existing ATES system in the Netherlands. Reconstruction of flow rates and injection and extraction temperatures from hourly logs of operational data from 2005 to 2012 show that the average thermal recovery is 82 % for cold storage and 68 % for heat storage. Subsurface heat transport is monitored using distributed temperature sensing. Although the measurements reveal unequal distribution of flow rate over different parts of the well screen and preferential flow due to aquifer heterogeneity, sufficient well spacing has avoided thermal interference. However, oversizing of well spacing may limit the number of systems that can be realized in an area and lower the potential of ATES.

Heat and Mass Transport in Heat Pipe Wick Structures

OpenAIRE

Iverson, B. D.; Davis, T. W.; Garimella, S V; North, M. T.; Kang, S.

2007-01-01

Anovel experimental approach is developed for characterizing the performance of heat pipe wick structures. This approach simulates the actual operation of wick structures in a heat pipe. Open, partially submerged, sintered copper wicks of varying pore size are studied under the partially saturated conditions found in normal heat pipe operation. A vertical wick orientation, where the capillary lift is in opposition to gravity, is selected to test the wicks under the most demanding conditions. ...

Feasibility of geothermal space/water heating for Mammoth Lakes Village, California. Final report, September 1976--September 1977

Energy Technology Data Exchange (ETDEWEB)

Sims, A.V.; Racine, W.C.

1977-12-01

Results of a study to determine the technical, economic, and environmental feasibility of geothermal district heating for Mammoth Lakes Village, California are reported. The geothermal district heating system selected is technically feasible and will use existing technology in its design and operation. District heating can provide space and water heating energy for typical customers at lower cost than alternative sources of energy. If the district heating system is investor owned, lower costs are realized after five to six years of operation, and if owned by a nonprofit organization, after zero to three years. District heating offers lower costs than alternatives much sooner in time if co-generation and/or DOE participation in system construction are included in the analysis. During a preliminary environmental assessment, no potential adverse environmental impacts could be identified of sufficient consequence to preclude the construction and operation of the proposed district heating system. A follow-on program aimed at implementing district heating in Mammoth is outlined.

Quantitative Analysis of the Principal-Agent Problem in Commercial Buildings in the U.S.: Focus on Central Space Heating and Cooling

Energy Technology Data Exchange (ETDEWEB)

Blum, Helcio; Sathaye, Jayant

2010-05-14

We investigate the existence of the principal-agent (PA) problem in non-government, non-mall commercial buildings in the U.S. in 2003. The analysis concentrates on space heating and cooling energy consumed by centrally installed equipment in order to verify whether a market failure caused by the PA problem might have prevented the installation of energy-efficient devices in non-owner-occupied buildings (efficiency problem) and/or the efficient operation of space-conditioning equipment in these buildings (usage problem). Commercial Buildings Energy Consumption Survey (CBECS) 2003 data for single-owner, single-tenant and multi-tenant occupied buildings were used for conducting this evaluation. These are the building subsets with the appropriate conditions for assessing both the efficiency and the usage problems. Together, these three building types represent 51.9percent of the total floor space of all buildings with space heating and 59.4percent of the total end-use energy consumption of such buildings; similarly, for space cooling, they represent 52.7percent of floor space and 51.6percent of energy consumption. Our statistical analysis shows that there is a usage PA problem. In space heating it applies only to buildings with a small floor area (<_50,000 sq. ft.). We estimate that in 2003 it accounts for additional site energy consumption of 12.3 (+ 10.5 ) TBtu (primary energy consumption of 14.6 [+- 12.4] TBtu), corresponding to 24.0percent (+- 20.5percent) of space heating and 10.2percent (+- 8.7percent) of total site energy consumed in those buildings. In space cooling, however, the analysis shows that the PA market failure affects the complete set of studied buildings. We estimate that it accounts for a higher site energy consumption of 8.3 (+-4.0) TBtu (primary energy consumption of 25.5 [+- 12.2]TBtu), which corresponds to 26.5percent (+- 12.7percent) of space cooling and 2.7percent (+- 1.3percent) of total site energy consumed in those buildings.

Sizing Hydrogen Energy Storage in Consideration of Demand Response in Highly Renewable Generation Power Systems

Directory of Open Access Journals (Sweden)

Mubbashir Ali

2018-05-01

Full Text Available From an environment perspective, the increased penetration of wind and solar generation in power systems is remarkable. However, as the intermittent renewable generation briskly grows, electrical grids are experiencing significant discrepancies between supply and demand as a result of limited system flexibility. This paper investigates the optimal sizing and control of the hydrogen energy storage system for increased utilization of renewable generation. Using a Finnish case study, a mathematical model is presented to investigate the optimal storage capacity in a renewable power system. In addition, the impact of demand response for domestic storage space heating in terms of the optimal sizing of energy storage is discussed. Finally, sensitivity analyses are conducted to observe the impact of a small share of controllable baseload production as well as the oversizing of renewable generation in terms of required hydrogen storage size.

Natural convective flows in a horizontal channel provided with heating isothermal blocks: Effect of the inter blocks spacing

International Nuclear Information System (INIS)

Bakkas, M.; Hasnaoui, M.; Amahmid, A.

2010-01-01

A numerical study of laminar steady natural convection induced in a two dimensional horizontal channel provided with rectangular heating blocks, periodically mounted on its lower wall, is carried out. The blocks' surface temperature, T H ' , is maintained constant and the former are connected with adiabatic surfaces. The upper wall of the channel is maintained cold at a temperature T C ' H ' . Fluid flow, temperature fields and heat transfer rates are presented for different combinations of the governing parameters which are the Rayleigh number (10 2 ≤Ra≤2x10 6 ), the blocks' spacing (1/4≤C=l ' /H ' ≤1), the blocks' height (1/8≤B=h ' /H ' ≤1/2) and the relative width of the blocks (A=(L ' -l ' )/H ' =1/2). The results obtained in the case of air (Pr = 0.72) show that the flow structure and the heat transfer are significantly influenced by the control parameters. It is found that there are situations where the increase of the blocks' spacing leads to a reduction of heat transfer.