WorldWideScience

Sample records for cost optimal heat

  1. HECDOR: a heat exchanger cost and design optimization routine

    Energy Technology Data Exchange (ETDEWEB)

    Turner, S.E.; Madsen, W.W.

    1977-04-01

    An update is presented on a series of four computer codes developed by the Bureau of Mines. The programs were developed to evaluate design parameters and cost of heat exchangers. The major differences in three of the programs were concerned with pumping costs; the first (N = 1) used both fluids, the second (N = 2) used tube side fluid, and the third (N = 3) used shell side fluid as a base for prime parameters. All three assumed no change in phase. The fourth program (N = 4) assumed a change of phase on the shell side.

  2. Analytical Thermal and Cost Optimization of Micro-Structured Plate-Fin Heat Sink

    DEFF Research Database (Denmark)

    Rezaniakolaei, Alireza; Rosendahl, Lasse

    Microchannel heat sinks have been widely used in the field of thermo-fluids due to the rapid growth in technological applications which require high rates of heat transfer in relatively small spaces and volumes. In this work, a micro plate-fin heat sink is optimized parametrically, to minimize...... the thermal resistance and to maximize the cost performance of the heat sink. The width and the height of the microchannels, and the fin thickness are analytically optimized at a wide range of pumping power. Using an effective numeric test, the generated equations also discuss the optimum parameters at three...... sizes of the substrate plat of the heat sink. Results show that, at any pumping power there are specific values of the channel width and fin thickness which produce minimum thermal resistance in the heat sink. The results also illustrate that, a larger channel width and a smaller fin thickness lead...

  3. Optimization of Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Ivan Catton

    2010-10-01

    The objective of this research is to develop tools to design and optimize heat exchangers (HE) and compact heat exchangers (CHE) for intermediate loop heat transport systems found in the very high temperature reator (VHTR) and other Generation IV designs by addressing heat transfer surface augmentation and conjugate modeling. To optimize heat exchanger, a fast running model must be created that will allow for multiple designs to be compared quickly. To model a heat exchanger, volume averaging theory, VAT, is used. VAT allows for the conservation of mass, momentum and energy to be solved for point by point in a 3 dimensional computer model of a heat exchanger. The end product of this project is a computer code that can predict an optimal configuration for a heat exchanger given only a few constraints (input fluids, size, cost, etc.). As VAT computer code can be used to model characteristics )pumping power, temperatures, and cost) of heat exchangers more quickly than traditional CFD or experiment, optimization of every geometric parameter simultaneously can be made. Using design of experiment, DOE and genetric algorithms, GE, to optimize the results of the computer code will improve heat exchanger disign.

  4. NLP modeling for the optimization of LiBr-H2O absorption refrigeration systems with exergy loss rate, heat transfer area, and cost as single objective functions

    DEFF Research Database (Denmark)

    Mussati, Sergio F.; Gernaey, Krist; Morosuk, Tatiana

    2016-01-01

    exergy loss rate, the total heat transfer area, and the total annual cost of the system. It was found that the optimal solution obtained by minimization of the total exergy loss rate provides “theoretical” upper bounds not only for the total heat transfer area of the system but also for each process unit...... and all stream temperatures, while the optimal solution obtained by minimization of the total heat transfer area provides the lower bounds for these model variables, to solve a cost optimization problem. The minimization of the total exergy loss rate by varying parametrically the available total heat...... and quantitatively with increasing available total heat transfer area. These optimization results allowed to find a “practical” value of the total heat transfer area, i.e. no benefits can be obtained by increasing the available total heat transfer area above this value since the minimal total exergy loss value...

  5. METHODOLOGY FOR DETERMINING THE OPTIMAL CLEANING PERIOD OF HEAT EXCHANGERS BY USING THE CRITERIA OF MINIMUM COST

    Directory of Open Access Journals (Sweden)

    Yanileisy Rodríguez Calderón

    2015-04-01

    Full Text Available One of the most serious problems of the Process Industry is that when planning the maintenance of the heat exchangers is not applied the methodologies based on economic criteria to optimize periods of cleaning surfaces resulting in additional costs for the company and for the country. This work develops and proposes a methodical based on the criterion of Minimum Cost for determining the optimal cleaning period. It is given an example of application of this method to the case of intercoolers of a centrifugal compressor with a high fouling level.It occurs this because is used sea water with many microorganisms as cooling agent which severely embeds transfer surfaces of side water. The methodology employed can be generalized to other applications.

  6. From Consumption to Prosumption - Operational Cost Optimization for Refrigeration System With Heat Waste Recovery

    DEFF Research Database (Denmark)

    Minko, Tomasz; Garcia, Jesus Lago; Bendtsen, Jan Dimon;

    2017-01-01

    Implementation of liquid cooling transforms a refrigeration system into a combined cooling and heating system. Reclaimed heat can be used for building heating purposes or can be sold. Carbon dioxide based refrigeration systems are considered to have a particularly high potential for becoming ecient...... heat energy producers. In this paper a CO2 system that operates in the subcritical region is examined. Modelling approach is presented, and used for operation optimisation by way of non-linear model predictive control techniques. Assuming that the heat is sold when using both objective functions...

  7. Cost Efficient Optimization Based Supervisory Controller for Supermarket Subsystems with Heat Recovery

    DEFF Research Database (Denmark)

    Minko, Tomasz; Wisniewski, Rafal; Bendtsen, Jan Dimon

    2015-01-01

    In this paper, we present a simple modelling approach for a thermal system, which consists of heating, ventilation, air conditioning system (HVAC) and a vapor compression cycle (VCC) system, with one loop heat recovery. In addition a simple model for water tank is presented, in which the reclaimed...... controllers of supermarkets subsystems. We find that when reliable information about the high price period is available, it is profitable to use the refrigeration system to generate heat during the low price period, store it and use it to substitute the conventional heater during the high price period....

  8. Optimizing the Costs of Solid Sorbent-Based CO2 Capture Process Through Heat Integration

    Energy Technology Data Exchange (ETDEWEB)

    Sjostrom, Sharon [Ada-Es, Inc., Highlands Ranch, CO (United States)

    2016-03-18

    The focus of this project was the ADAsorb™ CO2 Capture Process, a temperature-swing adsorption process that incorporates a three-stage fluidized bed as the adsorber and a single-stage fluidized bed as the regenerator. ADAsorb™ system was designed, fabricated, and tested under DOE award DEFE0004343. Two amine-based sorbents were evaluated in conjunction with the ADAsorb™ process: “BN”, an ion-exchange resin; and “OJ”, a metal organic framework (MOF) sorbent. Two cross heat exchanger designs were evaluated for use between the adsorber and regenerator: moving bed and fluidized bed. The fluidized bed approach was rejected fairly early in the project because the additional electrical load to power blowers or fans to overcome the pressure drop required for fluidization was estimated to be nominally three times the electrical power that could be generated from the steam saved through the use of the cross heat exchanger. The Energy Research Center at Lehigh University built and utilized a process model of the ADAsorb™ capture process and integrated this model into an existing model of a supercritical PC power plant. The Lehigh models verified that, for the ADAsorb™ system, the largest contributor to parasitic power was lost electrical generation, which was primarily electric power which the host plant could not generate due to the extraction of low pressure (LP) steam for sorbent heating, followed by power for the CO2 compressor and the blower or fan power required to fluidize the adsorber and regenerator. Sorbent characteristics such as the impacts of moisture uptake, optimized adsorption and regeneration temperature, and sensitivity to changes in pressure were also included in the modeling study. Results indicate that sorbents which adsorb more than 1-2% moisture by weight are unlikely to be cost competitive unless they have an extremely high CO2 working capacity that well exceeds 15% by weight. Modeling also revealed

  9. Heliostat cost optimization study

    Science.gov (United States)

    von Reeken, Finn; Weinrebe, Gerhard; Keck, Thomas; Balz, Markus

    2016-05-01

    This paper presents a methodology for a heliostat cost optimization study. First different variants of small, medium sized and large heliostats are designed. Then the respective costs, tracking and optical quality are determined. For the calculation of optical quality a structural model of the heliostat is programmed and analyzed using finite element software. The costs are determined based on inquiries and from experience with similar structures. Eventually the levelised electricity costs for a reference power tower plant are calculated. Before each annual simulation run the heliostat field is optimized. Calculated LCOEs are then used to identify the most suitable option(s). Finally, the conclusions and findings of this extensive cost study are used to define the concept of a new cost-efficient heliostat called `Stellio'.

  10. Optimized ground coupled heat pump mechanical package

    Energy Technology Data Exchange (ETDEWEB)

    Catan, M.A.

    1984-01-01

    The system which was optimized was a horizontal earth coil in a given house in the Pittsburgh area. The types of components used in the heat pump are essentially conventional. The method of this study is derived from one used to optimize an air-source heat pump for operation at standard steady state conditions. A computer model, created at Oak Ridge National Laboratory (ORNL), is used to predict heat pump performance for specified configuration and operating conditions. A predetermined set of design parameters is automatically altered by a constrained minimization program (a Numerical Algorithms Group library routine hereafter referred to as the optimizer) to find the combination for which the highest COP is predicted by the heat pump model. In the present study, the set of parameters to be varied include some pertaining to the ground coil as well as some pertaining to the heat pump. The optimizer, in this case, pursues a minimum life cycle cost which is calculated using the heat pump model, a ground coil model (called FTECM for Fast Transient Earth Coil model), and a parameterized cost model. The flow chart shows how the optimizer interacts with these programs to minimize life cycle cost.

  11. Optimizing operation costs of the heating system of a household using model predictive control considering a local PV installation

    DEFF Research Database (Denmark)

    Koch-Ciobotaru, Cosmin; Isleifsson, Fridrik Rafn; Gehrke, Oliver

    2012-01-01

    the effects of their large penetration in the distribution grid and reduces overloading the grid capacity, which is an increasing problem for the power system. The controller uses 24 hour prediction data for the ambient temperature, the solar irradiance, and for the PV output power. Simulation results...... of a thermostatic controller, a MPC with grid price optimization, and the proposed MPC are presented and discussed....

  12. Heat exchanger design based on economic optimization

    Energy Technology Data Exchange (ETDEWEB)

    Caputo, Antonio C.; Pelagagge, Marcello P.; Salini, Paolo [University of l' Aquila (Italy). Faculty of Engineering], e-mail: caputo@ing.inivaq.it, e-mail: pelmar@ing.inivaq.it, e-mail: salini@ing.inivaq.it

    2006-07-01

    Owing to the wide utilization of heat exchangers in industrial processes their cost minimization is an important target for both designers and users. Traditional design approaches are based on iterative procedures which assume a configuration and gradually change design parameters until a satisfying solution is reached which meets the design specifications. However, such methods, besides being time consuming, do not guarantee the reach of an optimal solution. In this paper a procedure for optimal design for shell and tube heat exchangers is proposed which utilizes a genetic algorithm to minimize the total discounted cost of the equipment including the capital investment and pumping related annual energy expenditures. In order to verify the performances of the proposed method four case studies are also presented showing that total cost reductions greater than 15% are feasible respect traditionally designed exchangers. (author)

  13. Wind Electrolysis: Hydrogen Cost Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Saur, G.; Ramsden, T.

    2011-05-01

    This report describes a hydrogen production cost analysis of a collection of optimized central wind based water electrolysis production facilities. The basic modeled wind electrolysis facility includes a number of low temperature electrolyzers and a co-located wind farm encompassing a number of 3MW wind turbines that provide electricity for the electrolyzer units.

  14. Optimizing Sustainable Geothermal Heat Extraction

    Science.gov (United States)

    Patel, Iti; Bielicki, Jeffrey; Buscheck, Thomas

    2016-04-01

    Geothermal heat, though renewable, can be depleted over time if the rate of heat extraction exceeds the natural rate of renewal. As such, the sustainability of a geothermal resource is typically viewed as preserving the energy of the reservoir by weighing heat extraction against renewability. But heat that is extracted from a geothermal reservoir is used to provide a service to society and an economic gain to the provider of that service. For heat extraction used for market commodities, sustainability entails balancing the rate at which the reservoir temperature renews with the rate at which heat is extracted and converted into economic profit. We present a model for managing geothermal resources that combines simulations of geothermal reservoir performance with natural resource economics in order to develop optimal heat mining strategies. Similar optimal control approaches have been developed for managing other renewable resources, like fisheries and forests. We used the Non-isothermal Unsaturated-saturated Flow and Transport (NUFT) model to simulate the performance of a sedimentary geothermal reservoir under a variety of geologic and operational situations. The results of NUFT are integrated into the optimization model to determine the extraction path over time that maximizes the net present profit given the performance of the geothermal resource. Results suggest that the discount rate that is used to calculate the net present value of economic gain is a major determinant of the optimal extraction path, particularly for shallower and cooler reservoirs, where the regeneration of energy due to the natural geothermal heat flux is a smaller percentage of the amount of energy that is extracted from the reservoir.

  15. District Heating Network Design and Configuration Optimization with Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Hongwei Li

    2013-12-01

    Full Text Available In this paper, the configuration of a district heating network which connects from the heating plant to the end users is optimized. Each end user in the network represents a building block. The connections between the heat generation plant and the end users are represented with mixed integer and the pipe friction and heat loss formulations are non-linear. In order to find the optimal district heating network configuration, genetic algorithm which handles the mixed integer nonlinear programming problem is chosen. The network configuration is represented with binary and integer encoding and is optimized in terms of the net present cost. The optimization results indicates that the optimal DH network configuration is determined by multiple factors such as the consumer heating load, the distance between the heating plant to the consumer, the design criteria regarding the pressure and temperature limitation, as well as the corresponding network heat loss.

  16. Heat Sink Design and Optimization

    Science.gov (United States)

    2015-12-01

    Natural convection Radiation Design Modeling Optimization 16. SECURITY CLASSIFICATION OF: 17...Hs = 3.94 in.  Width Ws = 5.42 in.  Fins  Height Hf = 0.98 in.  Length...different fin thicknesses (tf) The next parameter considered was fin height, Hf . Smaller height has a negative influence on overall heat sink

  17. Optimization of Heat Treatment in Aspect of Production’s Costs Reducing and Improving of Casting Quality from Duplex Cast Steel

    Directory of Open Access Journals (Sweden)

    D. Dyja

    2007-07-01

    Full Text Available The paper determines possibilities of cost optimisation in the production of GX2CrNiMoCu25-6-3-3 type duplex cast steel castings through selection of appropriate solution heat treatment temperature, which value depends on the content of alloying elements. Metallographic analysis was carried out for as-cast and heat treated cast steel. Hardness and impact strength of the cast steel were determined, which were correlated with the volume fraction of phases determined by means of ImagePro computer image analyser. It has been shown that increased carbon content creates a need to use higher treatment temperatures, thereby increasing the production cost. With increasing carbon content the cast steel hardness after solution heat treatment increases, however, crack resistance decreases

  18. Optimal control of induction heating processes

    CERN Document Server

    Rapoport, Edgar

    2006-01-01

    This book introduces new approaches to solving optimal control problems in induction heating process applications. Optimal Control of Induction Heating Processes demonstrates how to apply and use new optimization techniques for different types of induction heating installations. Focusing on practical methods for solving real engineering optimization problems, the text features a variety of specific optimization examples for induction heater modes and designs, particularly those used in industrial applications. The book describes basic physical phenomena in induction heating and induction

  19. Topology Optimization of Thermal Heat Sinks

    DEFF Research Database (Denmark)

    Klaas Haertel, Jan Hendrik; Engelbrecht, Kurt; Lazarov, Boyan Stefanov

    2015-01-01

    In this paper, topology optimization is applied to optimize the cooling performance of thermal heat sinks. The coupled two-dimensional thermofluid model of a heat sink cooled with forced convection and a density-based topology optimization including density filtering and projection are implemented...... in COMSOL Multiphysics. The optimization objective is to minimize the heat sink’s temperature for a prescribed pressure drop and fixed heat generation. To conduct the optimization, COMSOL’s Optimization Module with GCMMA as the optimization method is used. The implementation of this topology optimization...

  20. Optimization of a ground coupled heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, V.D.; Catan, M.A.

    1984-01-01

    A cooperative analytical project has optimized a horizontal ground coil heat pump system for the Pittsburgh climate. This is the first step in the exploration of several advanced designs including various ground coil devices and advanced heat pump components. The project made use of new and existing design tools to simulate system performance and determine first cost. The system life cycle cost was minimized while constraining the system to meet the design day cooling load using a function minimizing program. Among the system parameters considered were: air-to-refrigerant frontal area, air-to-refrigerant fin pitch, air-to-refrigerant air flowrate, compressor displacement, liquid-to-refrigerant coil length, liquid-to-refrigerant coil diameter, ground coil fluid flowrate, ground coil length, and ground coil depth.

  1. Heat savings and heat generation technologies: Modelling of residential investment behaviour with local health costs

    DEFF Research Database (Denmark)

    Zvingilaite, Erika; Klinge Jacobsen, Henrik

    2015-01-01

    their primary heating source with secondary heating e.g. a woodstove. This choice results in increased indoor air pollution with fine particles causing health effects. We integrate health cost due to use of woodstoves into household optimisation of heating expenditures. The results show that due...... heating comfort is minimised. The private solution may deviate from the socio-economical optimal solution and we suggest changes to policy to incentivise the individuals to make choices more in line with the socio-economic optimal mix of energy savings and technologies. The households can combine...

  2. Optimal Ground Source Heat Pump System Design

    Energy Technology Data Exchange (ETDEWEB)

    Ozbek, Metin [ENVIRON; Yavuzturk, Cy [University of Hartford; Pinder, George [University of Vermont

    2015-04-15

    Despite the facts that GSHPs first gained popularity as early as the 1940’s and they can achieve 30 to 60 percent in energy savings and carbon emission reductions relative to conventional HVAC systems, the use of geothermal energy in the U.S. has been less than 1 percent of the total energy consumption. The key barriers preventing this technically-mature technology from reaching its full commercial potential have been its high installation cost and limited consumer knowledge and trust in GSHP systems to deliver the technology in a cost-effective manner in the market place. Led by ENVIRON, with support from University Hartford and University of Vermont, the team developed and tested a software-based a decision making tool (‘OptGSHP’) for the least-cost design of ground-source heat pump (‘GSHP’) systems. OptGSHP combines state of the art optimization algorithms with GSHP-specific HVAC and groundwater flow and heat transport simulation. The particular strength of OptGSHP is in integrating heat transport due to groundwater flow into the design, which most of the GSHP designs do not get credit for and therefore are overdesigned.

  3. Optimal Ground Source Heat Pump System Design

    Energy Technology Data Exchange (ETDEWEB)

    Ozbek, Metin [Environ Holdings Inc., Princeton, NJ (United States); Yavuzturk, Cy [Univ. of Hartford, West Hartford, CT (United States); Pinder, George [Univ. of Vermont, Burlington, VT (United States)

    2015-04-01

    Despite the facts that GSHPs first gained popularity as early as the 1940’s and they can achieve 30 to 60 percent in energy savings and carbon emission reductions relative to conventional HVAC systems, the use of geothermal energy in the U.S. has been less than 1 percent of the total energy consumption. The key barriers preventing this technically-mature technology from reaching its full commercial potential have been its high installation cost and limited consumer knowledge and trust in GSHP systems to deliver the technology in a cost-effective manner in the market place. Led by ENVIRON, with support from University Hartford and University of Vermont, the team developed and tested a software-based a decision making tool (‘OptGSHP’) for the least-cost design of ground-source heat pump (‘GSHP’) systems. OptGSHP combines state of the art optimization algorithms with GSHP-specific HVAC and groundwater flow and heat transport simulation. The particular strength of OptGSHP is in integrating heat transport due to groundwater flow into the design, which most of the GSHP designs do not get credit for and therefore are overdesigned.

  4. Optimal design of the separate type heat pipe heat exchanger

    Institute of Scientific and Technical Information of China (English)

    YU Zi-tao; HU Ya-cai; CEN Ke-fa

    2005-01-01

    Separate type heat pipe heat exchangers are often used for large-scale heat exchanging. The arrangement of such a heat exchanger conveniently allows heat input to and output from the heat exchanger at remote locations. The traditional method of designing an ordinary HPHE (heat pipe heat exchanger) is commonly applied in the separate type exchanger design, but the calculations have to be carried out separately, which makes it very complicated. In this work, the ε-NTU (effectiveness-Number of Transfer Units) method was applied for optimization analysis of single- or multi-level separate type heat pipe heat exchangers. An optimizing formula for single-level separate type heat pipe heat exchangers was obtained. The optimizing principles of effectiveness-NTU and heat transfer rate by the equal distribution method for multi-level separate type heat pipe heat exchanger are presented. The design of separate type heat pipe heat exchangers by the optimizing method is more convenient and faster than by the traditional method.

  5. Optimization of existing heat-integrated refinery distillation systems

    Energy Technology Data Exchange (ETDEWEB)

    Gadalla, M.; Jobson, M.; Smith, R.

    2003-01-01

    Existing refinery distillation systems are highly energy-intensive, and have complex column configurations that interact strongly with the associated heat exchanger network. An optimization approach is developed for existing refinery distillation processes. The optimization framework includes shortcut models developed for the simulation of the existing distillation column, and a retrofit shortcut model for the heat exchanger network. The existing distillation process is optimized by changing key operating parameters, while simultaneously accounting for hydraulic limitations and the design and the performance of the existing heat exchanger network. A case study shows that a reduction in energy consumption and operating costs of over 25% can be achieved. (Author)

  6. Cost Overrun Optimism: Fact or Fiction

    Science.gov (United States)

    2016-02-29

    Image designed by Diane Fleischer Cost Overrun Optimism : FACT or FICTION? Maj David D. Christensen, USAF Program managers are advocates by...3 : 254–271 A Publication of the Defense Acquisition University http://www.dau.mil Cost Overrun Optimism : Fact or Fiction? According to Gansler...generally confirmed. From as early as the 10 percent completion point, the optimism of the pro- jected cost overrun at completion is apparent. Throughout

  7. Portfolio Optimization Model with Transaction Costs

    Institute of Scientific and Technical Information of China (English)

    Shu-ping Chen; Chong Li; Sheng-hong Li; Xiong-wei Wu

    2002-01-01

    The purpose of the article is to formulate, under the l∞ risk measure, a model of portfolio selection with transaction costs and then investigate the optimal strategy within the proposed. The characterization of a optimal strategy and the efficient algorithm for finding the optimal strategy are given.

  8. Topology optimization for transient heat transfer problems

    DEFF Research Database (Denmark)

    Zeidan, Said; Sigmund, Ole; Lazarov, Boyan Stefanov

    The focus of this work is on passive control of transient heat transfer problems using the topology optimization (TopOpt) method [1]. The goal is to find distributions of a limited amount of phase change material (PCM), within a given design domain, which optimizes the heat energy storage [2]. Our......, TopOpt has later been extended to transient problems in mechanics and photonics (e.g. [5], [6] and [7]). In the presented approach, the optimization is gradient-based, where in each iteration the non-steady heat conduction equation is solved,using the finite element method and an appropriate time...

  9. Optimal Control of Diesel Engines with Waste Heat Recovery System

    NARCIS (Netherlands)

    Willems, F.P.T.; Donkers, M.C.F.; Kupper, F.

    2014-01-01

    This study presents an integrated energy and emission management strategy for a Euro-VI diesel engine with Waste Heat Recovery (WHR) system. This Integrated Powertrain Control (IPC) strategy optimizes the CO2-NOx trade-off by minimizing the operational costs associated with fuel and AdBlue consumpti

  10. Optimal Heating in Heat-Treatment Process Based on Grey Asynchronous Particle Swarm Optimization

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    To ensure plate heating quality and reduce energy consumption in heat-treatment process, optimal heating for plates in a roller hearth furnace was investigated and a new strategy for heating procedure optimization was developed. During solving process, plate temperature forecast model based on heat transfer mechanics was established to calculate plate temperature with the assumed heating procedure. In addition, multi-objective feature of optimal heating was analyzed. And the method, which is composed of asynchronous particle swarm optimization and grey relational analysis, was adopted for solving the multi-objective problem. The developed strategy for optimizing heating has been applied to the mass production. The result indicates that the absolute plate discharging temperature deviation between measured value and target value does not exceed ± 8 ℃, and the relative deviation is less than ± 0.77%.

  11. Selection and costing of heat exchangers

    Science.gov (United States)

    1992-12-01

    ESDU 92013 gives guidance on the selection of heat exchanger types for a given duty against various criteria; they include the general characteristics, together with such detailed aspects as the ranges of pressure and temperature appropriate, compatibility with the fluids involved, space and weight requirements, and cleaning accessibility and maintenance. That allows an initial choice to be made from 18 principal types of exchangers. The various types are all illustrated. A final choice can then be made between the feasible types on the basis of costs. Detailed costing data provided by manufacturers are tabulated as a function of heat load, operating pressure and the types of cold- and hot-side fluids for the following types of exchangers: shell-and-tube, double-pipe, printed-circuit, plate-fin, air-cooled and welded plate. Costing data are also tabulated as a function of heat load and the types of cold- and hot-side fluids for gasketed-plate exchangers. Seven worked examples of selection based on technical suitability and using the tabulated cost data illustrate fully the use of the information.

  12. Optimized ground coupled heat pump mechanical package

    Energy Technology Data Exchange (ETDEWEB)

    Catan, M.A.

    1987-01-01

    This project addresses the question of how well a ground coupled heat pump system could perform with a heat pump which was designed specifically for such systems operating in a northern climate. Conventionally, systems are designed around water source heat pumps which are not designed for ground coupled heat pump application. The objective of the project is to minimize the life cycle cost for a ground coupled system given the freedom to design the heat pump and the ground coil in concert. In order to achieve this objective a number of modeling tools were developed which will likely be of interest in their own right.

  13. Optimization of heat saving in buildings using unsteady heat transfer model

    Directory of Open Access Journals (Sweden)

    Dedinec Aleksandra

    2015-01-01

    Full Text Available Reducing the energy consumption growth rate is increasingly becoming one of the main challenges for ensuring sustainable development, particularly in the buildings as the largest end-use sector in many countries. Along this line, the aim of this paper is to analyse the possibilities for energy savings in the construction of new buildings and reconstruction of the existing ones developing a tool that, in terms of the available heating technologies and insulation, provides answer to the problem of optimal cost effective energy consumption. The tool is composed of an unsteady heat transfer model which is incorporated into a cost-effective energy saving optimization. The unsteady heat transfer model uses annual hourly meteorological data, chosen as typical for the last ten-year period, as well as thermo physical features of the layers of the building walls. The model is tested for the typical conditions in the city of Skopje, Macedonia. The results show that the most cost effective heating technology for the given conditions is the wood fired stove, followed by the inverter air-conditioner. The centralized district heating and the pellet fired stoves are the next options. The least cost effective option is the panel that uses electricity. In this paper, the optimal insulation thickness is presented for each type of heating technology.

  14. 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

  15. Optimal Heating Strategies for a Convection Oven

    NARCIS (Netherlands)

    Stigter, J.D.; Scheerlinck, N.; Nicolai, B.M.; Impe, van J.F.

    2001-01-01

    In this study classical control theory is applied to a heat conduction model with convective boundary conditions. Optimal heating strategies are obtained through solution of an associated algebraic Riccati equation for a finite horizon linear quadratic regulator (LQR). The large dimensional system

  16. Optimization of Transient Heat Exchanger Performance for Improved Energy Efficiency

    Science.gov (United States)

    Bran Anleu, Gabriela; Kavehpour, Pirouz; Lavine, Adrienne; Wirz, Richard

    2014-11-01

    Heat exchangers are used in a multitude of applications within systems for energy generation, energy conversion, or energy storage. Many of these systems (e.g. solar power plants) function under transient conditions, but the design of the heat exchangers is typically optimized assuming steady state conditions. There is a potential for significant energy savings if the transient behavior of the heat exchanger is taken into account in designing the heat exchanger by optimizing its operating conditions in relation to the transient behavior of the overall system. The physics of the transient behavior of a heat exchanger needs to be understood to provide design parameters for transient heat exchangers to deliver energy savings. A numerical model was used to determine the optimized mass flow rates thermal properties for a thermal energy storage system. The transient behavior is strongly linked to the dimensionless parameters relating fluid properties, the mass flow rates, and the temperature of the fluids at the inlet of each stream. Smart metals, or advanced heat exchanger surface geometries and methods of construction will be used to meet the three goals mentioned before: 1) energy and cost reduction, 2) size reduction, and 3) optimal performance for all modes of operation.

  17. Investigation and optimization of the depth of flue gas heat recovery in surface heat exchangers

    Science.gov (United States)

    Bespalov, V. V.; Bespalov, V. I.; Melnikov, D. V.

    2017-09-01

    Economic issues associated with designing deep flue gas heat recovery units for natural gas-fired boilers are examined. The governing parameter affecting the performance and cost of surface-type condensing heat recovery heat exchangers is the heat transfer surface area. When firing natural gas, the heat recovery depth depends on the flue gas temperature at the condenser outlet and determines the amount of condensed water vapor. The effect of the outlet flue gas temperature in a heat recovery heat exchanger on the additionally recovered heat power is studied. A correlation has been derived enabling one to determine the best heat recovery depth (or the final cooling temperature) maximizing the anticipated reduced annual profit of a power enterprise from implementation of energy-saving measures. Results of optimization are presented for a surface-type condensing gas-air plate heat recovery heat exchanger for the climatic conditions and the economic situation in Tomsk. The predictions demonstrate that it is economically feasible to design similar heat recovery heat exchangers for a flue gas outlet temperature of 10°C. In this case, the payback period for the investment in the heat recovery heat exchanger will be 1.5 years. The effect of various factors on the optimal outlet flue gas temperature was analyzed. Most climatic, economical, or technological factors have a minor effect on the best outlet temperature, which remains between 5 and 20°C when varying the affecting factors. The derived correlation enables us to preliminary estimate the outlet (final) flue gas temperature that should be used in designing the heat transfer surface of a heat recovery heat exchanger for a gas-fired boiler as applied to the specific climatic conditions.

  18. Numerical topology optimization of heat sinks

    OpenAIRE

    Van Oevelen, Tijs; Baelmans, Martine

    2014-01-01

    The availability of flexible production techniques challenges their full exploitation during thermo-hydraulic design of micro heat sinks. In this context, a systematic approach capable to take advantage of the practically unlimited design freedom is highly desirable. Therefore, we propose to use topology optimization, a numerical design optimization method well-established in structural mechanics problems. In this paper, the fundamentals of topology optimization, and its application in thermo...

  19. Cost Optimization of Product Families using Analytic Cost Models

    DEFF Research Database (Denmark)

    Brunø, Thomas Ditlev; Nielsen, Peter

    2012-01-01

    This paper presents a new method for analysing the cost structure of a mass customized product family. The method uses linear regression and backwards selection to reduce the complexity of a data set describing a number of historical product configurations and incurred costs. By reducing the data...... set, the configuration variables which best describe the variation in product costs are identified. The method is tested using data from a Danish manufacturing company and the results indicate that the method is able to identify the most critical configuration variables. The method can be applied...... in product family redesign projects focusing on cost reduction to identify which modules contribute the most to cost variation and should thus be optimized....

  20. Cost Optimization of Product Families using Analytic Cost Models

    DEFF Research Database (Denmark)

    Brunø, Thomas Ditlev; Nielsen, Peter

    2012-01-01

    This paper presents a new method for analysing the cost structure of a mass customized product family. The method uses linear regression and backwards selection to reduce the complexity of a data set describing a number of historical product configurations and incurred costs. By reducing the data...... set, the configuration variables which best describe the variation in product costs are identified. The method is tested using data from a Danish manufacturing company and the results indicate that the method is able to identify the most critical configuration variables. The method can be applied...... in product family redesign projects focusing on cost reduction to identify which modules contribute the most to cost variation and should thus be optimized....

  1. Gasification Plant Cost and Performance Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Samuel Tam; Alan Nizamoff; Sheldon Kramer; Scott Olson; Francis Lau; Mike Roberts; David Stopek; Robert Zabransky; Jeffrey Hoffmann; Erik Shuster; Nelson Zhan

    2005-05-01

    As part of an ongoing effort of the U.S. Department of Energy (DOE) to investigate the feasibility of gasification on a broader level, Nexant, Inc. was contracted to perform a comprehensive study to provide a set of gasification alternatives for consideration by the DOE. Nexant completed the first two tasks (Tasks 1 and 2) of the ''Gasification Plant Cost and Performance Optimization Study'' for the DOE's National Energy Technology Laboratory (NETL) in 2003. These tasks evaluated the use of the E-GAS{trademark} gasification technology (now owned by ConocoPhillips) for the production of power either alone or with polygeneration of industrial grade steam, fuel gas, hydrocarbon liquids, or hydrogen. NETL expanded this effort in Task 3 to evaluate Gas Technology Institute's (GTI) fluidized bed U-GAS{reg_sign} gasifier. The Task 3 study had three main objectives. The first was to examine the application of the gasifier at an industrial application in upstate New York using a Southeastern Ohio coal. The second was to investigate the GTI gasifier in a stand-alone lignite-fueled IGCC power plant application, sited in North Dakota. The final goal was to train NETL personnel in the methods of process design and systems analysis. These objectives were divided into five subtasks. Subtasks 3.2 through 3.4 covered the technical analyses for the different design cases. Subtask 3.1 covered management activities, and Subtask 3.5 covered reporting. Conceptual designs were developed for several coal gasification facilities based on the fluidized bed U-GAS{reg_sign} gasifier. Subtask 3.2 developed two base case designs for industrial combined heat and power facilities using Southeastern Ohio coal that will be located at an upstate New York location. One base case design used an air-blown gasifier, and the other used an oxygen-blown gasifier in order to evaluate their relative economics. Subtask 3.3 developed an advanced design for an air

  2. Ecological optimization for general heat engines

    Science.gov (United States)

    Long, Rui; Liu, Wei

    2015-09-01

    We conducted an analysis of efficiency and its bounds for general heat engines under the maximum ecological criterion. For generality, both nonisothermal heat-exchanging processes and internal dissipation were taken into consideration. When the product of the internal dissipation and the heat capacity ratio is one, the efficiency under the maximum ecological criterion is the same as that of the irreversible Carnot model. However, the efficiencies have different physical meanings and optimization spaces. Furthermore, the efficiency is independent of the time it takes to complete each process and the heat conductance. For other situations, numerical calculations were conducted to investigate the parameters' effects on optimal efficiency. When the dimensionless contact times approach zero, the irreversible Carnot model is recovered. The general upper and lower bounds of optimal efficiency are obtained by applying the asymmetric heat capacity ratio limits when the dimensionless contact times approach infinity. In addition, the efficiency of general endoreversible heat engines was investigated. The efficiency bounds of different real-life heat engines under the maximum ecological criterion are proposed.

  3. Optimal Management of Geothermal Heat Extraction

    Science.gov (United States)

    Patel, I. H.; Bielicki, J. M.; Buscheck, T. A.

    2015-12-01

    Geothermal energy technologies use the constant heat flux from the subsurface in order to produce heat or electricity for societal use. As such, a geothermal energy system is not inherently variable, like systems based on wind and solar resources, and an operator can conceivably control the rate at which heat is extracted and used directly, or converted into a commodity that is used. Although geothermal heat is a renewable resource, this heat can be depleted over time if the rate of heat extraction exceeds the natural rate of renewal (Rybach, 2003). For heat extraction used for commodities that are sold on the market, sustainability entails balancing the rate at which the reservoir renews with the rate at which heat is extracted and converted into profit, on a net present value basis. We present a model that couples natural resource economic approaches for managing renewable resources with simulations of geothermal reservoir performance in order to develop an optimal heat mining strategy that balances economic gain with the performance and renewability of the reservoir. Similar optimal control approaches have been extensively studied for renewable natural resource management of fisheries and forests (Bonfil, 2005; Gordon, 1954; Weitzman, 2003). Those models determine an optimal path of extraction of fish or timber, by balancing the regeneration of stocks of fish or timber that are not harvested with the profit from the sale of the fish or timber that is harvested. Our model balances the regeneration of reservoir temperature with the net proceeds from extracting heat and converting it to electricity that is sold to consumers. We used the Non-isothermal Unconfined-confined Flow and Transport (NUFT) model (Hao, Sun, & Nitao, 2011) to simulate the performance of a sedimentary geothermal reservoir under a variety of geologic and operational situations. The results of NUFT are incorporated into the natural resource economics model to determine production strategies that

  4. Messaging with Cost-Optimized Interstellar Beacons

    Science.gov (United States)

    Benford, James; Benford, Gregory; Benford, Dominic

    2010-06-01

    On Earth, how would we build galactic-scale beacons to attract the attention of extraterrestrials, as some have suggested we should do? From the point of view of expense to a builder on Earth, experience shows an optimum trade-off. This emerges by minimizing the cost of producing a desired power density at long range, which determines the maximum range of detectability of a transmitted signal. We derive general relations for cost-optimal aperture and power. For linear dependence of capital cost on transmitter power and antenna area, minimum capital cost occurs when the cost is equally divided between antenna gain and radiated power. For nonlinear power-law dependence, a similar simple division occurs. This is validated in cost data for many systems; industry uses this cost optimum as a rule of thumb. Costs of pulsed cost-efficient transmitters are estimated from these relations by using current cost parameters (/W, /m2) as a basis. We show the scaling and give examples of such beacons. Galactic-scale beacons can be built for a few billion dollars with our present technology. Such beacons have narrow "searchlight" beams and short "dwell times" when the beacon would be seen by an alien observer in their sky. More-powerful beacons are more efficient and have economies of scale: cost scales only linearly with range R, not as R2, so number of stars radiated to iincreases as the square of cost. On a cost basis, they will likely transmit at higher microwave frequencies, ˜10 GHz. The natural corridor to broadcast is along the galactic radius or along the local spiral galactic arm we are in. A companion paper asks "If someone like us were to produce a beacon, how should we look for it?"

  5. Messaging with Cost-Optimized Interstellar Beacons

    Science.gov (United States)

    Benford, James; Benford, Gregory; Benford, Dominic

    2010-01-01

    On Earth, how would we build galactic-scale beacons to attract the attention of extraterrestrials, as some have suggested we should do? From the point of view of expense to a builder on Earth, experience shows an optimum trade-off. This emerges by minimizing the cost of producing a desired power density at long range, which determines the maximum range of detectability of a transmitted signal. We derive general relations for cost-optimal aperture and power. For linear dependence of capital cost on transmitter power and antenna area, minimum capital cost occurs when the cost is equally divided between antenna gain and radiated power. For nonlinear power-law dependence, a similar simple division occurs. This is validated in cost data for many systems; industry uses this cost optimum as a rule of thumb. Costs of pulsed cost-efficient transmitters are estimated from these relations by using current cost parameters ($/W, $/sq m) as a basis. We show the scaling and give examples of such beacons. Galactic-scale beacons can be built for a few billion dollars with our present technology. Such beacons have narrow "searchlight" beams and short "dwell times" when the beacon would be seen by an alien observer in their sky. More-powerful beacons are more efficient and have economies of scale: cost scales only linearly with range R, not as R(exp 2), so number of stars radiated to increases as the square of cost. On a cost basis, they will likely transmit at higher microwave frequencies, -10 GHz. The natural corridor to broadcast is along the galactic radius or along the local spiral galactic arm we are in. A companion paper asks "If someone like us were to produce a beacon, how should we look for it?"

  6. Optimization of Borehole Heat Exchanger Arrays

    Science.gov (United States)

    Schulte, Daniel; Rühaak, Wolfram; Welsch, Bastian; Oladyshkin, Sergey; Sass, Ingo

    2016-04-01

    Arrays of borehole heat exchangers are an increasingly popular source for renewable energy. Furthermore, they can serve as borehole thermal energy storages for seasonally fluctuating heat sources like solar thermal energy or district heating grids. However, the uncertainty of geological parameters and the nonlinear behavior of the complex system make it difficult to simulate and predict the required design of borehole heat exchanger arrays. As a result, the arrays easily turn out to be over or undersized, which compromises the economic feasibility of these systems. Here, we present a novel optimization strategy for the design of borehole thermal energy storages. The arbitrary polynomial chaos expansion method is used to build a proxy model from a set of numerical training simulations, which allows for the consideration of parameter uncertainties. Thus, the resulting proxy model bypasses the problem of excessive computation time for the numerous function calls required for a mathematical optimization. Additionally, we iteratively refine the proxy model during the optimization procedure using additional numerical simulation runs. With the presented solution, many aspects of borehole heat exchanger arrays can be optimized under geological uncertainty.

  7. Cost optimal levels for energy performance requirements

    DEFF Research Database (Denmark)

    Thomsen, Kirsten Engelund; Aggerholm, Søren; Kluttig-Erhorn, Heike;

    This report summarises the work done within the Concerted Action EPBD from December 2010 to April 2011 in order to feed into the European Commission's proposal for a common European procedure for a Cost-Optimal methodology under the Directive on the Energy Performance of Buildings (recast) 2010/3...

  8. BASIMO - Borehole Heat Exchanger Array Simulation and Optimization Tool

    Science.gov (United States)

    Schulte, Daniel O.; Bastian, Welsch; Wolfram, Rühaak; Kristian, Bär; Ingo, Sass

    2017-04-01

    Arrays of borehole heat exchangers are an increasingly popular source for renewable energy. Furthermore, they can serve as borehole thermal energy storage (BTES) systems for seasonally fluctuating heat sources like solar thermal energy or district heating grids. The high temperature level of these heat sources prohibits the use of the shallow subsurface for environmental reasons. Therefore, deeper reservoirs have to be accessed instead. The increased depth of the systems results in high investment costs and has hindered the implementation of this technology until now. Therefore, research of medium deep BTES systems relies on numerical simulation models. Current simulation tools cannot - or only to some extent - describe key features like partly insulated boreholes unless they run fully discretized models of the borehole heat exchangers. However, fully discretized models often come at a high computational cost, especially for large arrays of borehole heat exchangers. We give an update on the development of BASIMO: a tool, which uses one dimensional thermal resistance and capacity models for the borehole heat exchangers coupled with a numerical finite element model for the subsurface heat transport in a dual-continuum approach. An unstructured tetrahedral mesh bypasses the limitations of structured grids for borehole path geometries, while the thermal resistance and capacity model is improved to account for borehole heat exchanger properties changing with depth. Thereby, partly insulated boreholes can be considered in the model. Furthermore, BASIMO can be used to improve the design of BTES systems: the tool allows for automated parameter variations and is readily coupled to other code like mathematical optimization algorithms. Optimization can be used to determine the required minimum system size or to increase the system performance.

  9. Optimal hedging of Derivatives with transaction costs

    CERN Document Server

    Aurell, E; Aurell, Erik; Muratore-Ginanneschi, Paolo

    2005-01-01

    We investigate the optimal strategy over a finite time horizon for a portfolio of stock and bond and a derivative in an multiplicative Markovian market model with transaction costs (friction). The optimization problem is solved by a Hamilton-Bellman-Jacobi equation, which by the verification theorem has well-behaved solutions if certain conditions on a potential are satisfied. In the case at hand, these conditions simply imply arbitrage-free ("Black-Scholes") pricing of the derivative. While pricing is hence not changed by friction allow a portfolio to fluctuate around a delta hedge. In the limit of weak friction, we determine the optimal control to essentially be of two parts: a strong control, which tries to bring the stock-and-derivative portfolio towards a Black-Scholes delta hedge; and a weak control, which moves the portfolio by adding or subtracting a Black-Scholes hedge. For simplicity we assume growth-optimal investment criteria and quadratic friction.

  10. OPTIMIZING HIGHWAY PROFILES FOR INDIVIDUAL COST ITEMS

    Directory of Open Access Journals (Sweden)

    Essam Dabbour

    2013-12-01

    Full Text Available According to the current practice, vertical alignment of a highway segment is usually selected by creating a profile showing the actual ground surface and selecting initial and final grades to minimize the overall cut and fill quantities. Those grades are connected together with a parabolic curve. However, in many highway construction or rehabilitation projects, the cost of cut may be substantially different from that of fill (e.g. in extremely hard soils where blasting is needed to cut the soil. In that case, an optimization process will be needed to minimize the overall cost of cut and fill rather than to minimize their quantities. This paper proposes a nonlinear optimization model to select optimum vertical curve parameters based on individual cost items of cut and fill. The parameters selected by the optimization model include the initial grade, the final grade, the station and elevation of the point of vertical curvature (PVC, and the station and elevation of the point of vertical tangency (PVT. The model is flexible to include any design constraints for particular design problems. Different application examples are provided using the Evolutionary Algorithm in Microsoft Excel’s Solver add-in. The application examples validated the model and demonstrated its advantage of minimizing the overall cost rather than minimizing the overall volume of cut and fill quantities.

  11. Cost Scaling of a Real-World Exhaust Waste Heat Recovery Thermoelectric Generator: A Deeper Dive

    Science.gov (United States)

    Hendricks, Terry J.; Yee, Shannon; LeBlanc, Saniya

    2016-03-01

    Cost is equally important to power density or efficiency for the adoption of waste heat recovery thermoelectric generators (TEG) in many transportation and industrial energy recovery applications. In many cases, the system design that minimizes cost (e.g., the /W value) can be very different than the design that maximizes the system's efficiency or power density, and it is important to understand the relationship between those designs to optimize TEG performance-cost compromises. Expanding on recent cost analysis work and using more detailed system modeling, an enhanced cost scaling analysis of a waste heat recovery TEG with more detailed, coupled treatment of the heat exchangers has been performed. In this analysis, the effect of the heat lost to the environment and updated relationships between the hot-side and cold-side conductances that maximize power output are considered. This coupled thermal and thermoelectric (TE) treatment of the exhaust waste heat recovery TEG yields modified cost scaling and design optimization equations, which are now strongly dependent on the heat leakage fraction, exhaust mass flow rate, and heat exchanger effectiveness. This work shows that heat exchanger costs most often dominate the overall TE system costs, that it is extremely difficult to escape this regime, and in order to achieve TE system costs of 1/W it is necessary to achieve heat exchanger costs of 1/(W/K). Minimum TE system costs per watt generally coincide with maximum power points, but preferred TE design regimes are identified where there is little cost penalty for moving into regions of higher efficiency and slightly lower power outputs. These regimes are closely tied to previously identified low cost design regimes. This work shows that the optimum fill factor F opt minimizing system costs decreases as heat losses increase, and increases as exhaust mass flow rate and heat exchanger effectiveness increase. These findings have profound implications on the design and

  12. The computational optimization of heat exchange efficiency in stack chimneys

    Energy Technology Data Exchange (ETDEWEB)

    Van Goch, T.A.J.

    2012-02-15

    For many industrial processes, the chimney is the final step before hot fumes, with high thermal energy content, are discharged into the atmosphere. Tapping into this energy and utilizing it for heating or cooling applications, could improve sustainability, efficiency and/or reduce operational costs. Alternatively, an unused chimney, like the monumental chimney at the Eindhoven University of Technology, could serve as an 'energy channeler' once more; it can enhance free cooling by exploiting the stack effect. This study aims to identify design parameters that influence annual heat exchange in such stack chimney applications and optimize these parameters for specific scenarios to maximize the performance. Performance is defined by annual heat exchange, system efficiency and costs. The energy required for the water pump as compared to the energy exchanged, defines the system efficiency, which is expressed in an efficiency coefficient (EC). This study is an example of applying building performance simulation (BPS) tools for decision support in the early phase of the design process. In this study, BPS tools are used to provide design guidance, performance evaluation and optimization. A general method for optimization of simulation models will be studied, and applied in two case studies with different applications (heating/cooling), namely; (1) CERES case: 'Eindhoven University of Technology monumental stack chimney equipped with a heat exchanger, rejects heat to load the cold source of the aquifer system on the campus of the university and/or provides free cooling to the CERES building'; and (2) Industrial case: 'Heat exchanger in an industrial stack chimney, which recoups heat for use in e.g. absorption cooling'. The main research question, addressing the concerns of both cases, is expressed as follows: 'what is the optimal set of design parameters so heat exchange in stack chimneys is optimized annually for the cases in which a

  13. Optimal design of district heating and cooling pipe network of seawater-source heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang-li; Duanmu, Lin; Shu, Hai-wen [School of Civil and Hydraulic Engineering, Dalian University of Technology, Dalian, Liaoning Province 116024 (China)

    2010-01-15

    The district heating and cooling (DHC) system of a seawater-source heat pump is large system engineering. The investments and the operational cost of DHC pipe network are higher than a tradition system. Traditional design methods only satisfy the needs of the technology but dissatisfy the needs of the economy, which not only waste a mass of money but also bring problems to the operation, the maintenance and the management. So we build a least-annualized-cost global optimal mathematic model that comprises all constrict conditions. Furthermore, this model considers the variety of heating load and cooling load, the operational adjustment in different periods of the year. Genetic algorithm (GA) is used to obtain the optimal combinations of discrete diameters. Some operators of GA are selected to reduce the calculation time and obtain good calculation accuracy. This optimal method is used to the design of the DHC network of Xinghai Bay commercial district which is a real engineering. The design optimization can avoid the matter of the hydraulic unbalance of the system, enhance the running efficiency and greatly reduce the annualized-cost comparing with the traditional design method. (author)

  14. Optimal Operation System of the Integrated District Heating System with Multiple Regional Branches

    Science.gov (United States)

    Kim, Ui Sik; Park, Tae Chang; Kim, Lae-Hyun; Yeo, Yeong Koo

    This paper presents an optimal production and distribution management for structural and operational optimization of the integrated district heating system (DHS) with multiple regional branches. A DHS consists of energy suppliers and consumers, district heating pipelines network and heat storage facilities in the covered region. In the optimal management system, production of heat and electric power, regional heat demand, electric power bidding and sales, transport and storage of heat at each regional DHS are taken into account. The optimal management system is formulated as a mixed integer linear programming (MILP) where the objectives is to minimize the overall cost of the integrated DHS while satisfying the operation constraints of heat units and networks as well as fulfilling heating demands from consumers. Piecewise linear formulation of the production cost function and stairwise formulation of the start-up cost function are used to compute nonlinear cost function approximately. Evaluation of the total overall cost is based on weekly operations at each district heat branches. Numerical simulations show the increase of energy efficiency due to the introduction of the present optimal management system.

  15. Tailoring Macroscale Response of Mechanical and Heat Transfer Systems by Topology Optimization of Microstructural Details

    DEFF Research Database (Denmark)

    Alexandersen, Joe; Lazarov, Boyan Stefanov

    2015-01-01

    -contrast material parameters is proposed to alleviate the high computational cost associated with solving the discrete systems arising during the topology optimization process. Problems within important engineering areas, heat transfer and linear elasticity, are considered for exemplifying the approach...

  16. Solar Water Heating with Low-Cost Plastic Systems (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2012-01-01

    Newly developed solar water heating technology can help Federal agencies cost effectively meet the EISA requirements for solar water heating in new construction and major renovations. This document provides design considerations, application, economics, and maintenance information and resources.

  17. 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....... Groundwater, seawater and air heat sources were compared with each other as well as to a scenario consisting of a combination of these heat sources. In addition, base load and peak load units were included. Characteristic parameters were the coefficient of performance, the number of full load hours...

  18. Operational cost minimization of heat pump for milk pasteurization in dairy.

    Science.gov (United States)

    Söylemez, Mehmet Sait

    2005-11-01

    A thermo economic optimization analysis is presented yielding simple algebraic formula for estimating the optimum operating conditions of interconnected heat pump assisted milk pasteurizing systems. The overall operational cost method including the cost of auxiliary heater is used in the present study, together with the thermal analyses of all system components, for thermo economic analysis of the system.

  19. Exergoeconomic optimization of an ammonia–water hybrid absorption–compression heat pump for heat supply in a spraydrying facility

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars

    2015-01-01

    load of 6.1 MW. The exhaust air from the drying process is 80 C. The implementation of anammonia–water hybrid absorption–compression heat pump to partly cover the heat load is investigated. A thermodynamic analysis is applied to determine optimal circulation ratios for a number of ammonia mass...... fractions and heat pump loads. An exergo economic optimization is applied to minimize the lifetime cost of the system. Technological limitations are imposed to constrain the solution to commercial components. The best possible implementation is identified in terms of heat load, ammonia mass fraction...

  20. GASIFICATION PLANT COST AND PERFORMANCE OPTIMIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Samuel S. Tam

    2002-05-01

    The goal of this series of design and estimating efforts was to start from the as-built design and actual operating data from the DOE sponsored Wabash River Coal Gasification Repowering Project and to develop optimized designs for several coal and petroleum coke IGCC power and coproduction projects. First, the team developed a design for a grass-roots plant equivalent to the Wabash River Coal Gasification Repowering Project to provide a starting point and a detailed mid-year 2000 cost estimate based on the actual as-built plant design and subsequent modifications (Subtask 1.1). This unoptimized plant has a thermal efficiency of 38.3% (HHV) and a mid-year 2000 EPC cost of 1,681 $/kW. This design was enlarged and modified to become a Petroleum Coke IGCC Coproduction Plant (Subtask 1.2) that produces hydrogen, industrial grade steam, and fuel gas for an adjacent Gulf Coast petroleum refinery in addition to export power. A structured Value Improving Practices (VIP) approach was applied to reduce costs and improve performance. The base case (Subtask 1.3) Optimized Petroleum Coke IGCC Coproduction Plant increased the power output by 16% and reduced the plant cost by 23%. The study looked at several options for gasifier sparing to enhance availability. Subtask 1.9 produced a detailed report on this availability analyses study. The Subtask 1.3 Next Plant, which retains the preferred spare gasification train approach, only reduced the cost by about 21%, but it has the highest availability (94.6%) and produces power at 30 $/MW-hr (at a 12% ROI). Thus, such a coke-fueled IGCC coproduction plant could fill a near term niche market. In all cases, the emissions performance of these plants is superior to the Wabash River project. Subtasks 1.5A and B developed designs for single-train coal and coke-fueled power plants. This side-by-side comparison of these plants, which contain the Subtask 1.3 VIP enhancements, showed their similarity both in design and cost (1,318 $/kW for the

  1. Cost Optimization and Technology Enablement COTSAT-1

    Science.gov (United States)

    Spremo, Stevan; Lindsay, Michael C.; Klupar, Peter Damian; Swank, Aaron J.

    2010-01-01

    Cost Optimized Test of Spacecraft Avionics and Technologies (COTSAT-1) is an ongoing spacecraft research and development project at NASA Ames Research Center (ARC). The space industry was a hot bed of innovation and development at its birth. Many new technologies were developed for and first demonstrated in space. In the recent past this trend has reversed with most of the new technology funding and research being driven by the private industry. Most of the recent advances in spaceflight hardware have come from the cell phone industry with a lag of about 10 to 15 years from lab demonstration to in space usage. NASA has started a project designed to address this problem. The prototype spacecraft known as Cost Optimized Test of Spacecraft Avionics and Technologies (COTSAT-1) and CheapSat work to reduce these issues. This paper highlights the approach taken by NASA Ames Research center to achieve significant subsystem cost reductions. The COSTAT-1 research system design incorporates use of COTS (Commercial Off The Shelf), MOTS (Modified Off The Shelf), and GOTS (Government Off The Shelf) hardware for a remote sensing spacecraft. The COTSAT-1 team demonstrated building a fully functional spacecraft for $500K parts and $2.0M labor. The COTSAT-1 system, including a selected science payload, is described within this paper. Many of the advancements identified in the process of cost reduction can be attributed to the use of a one-atmosphere pressurized structure to house the spacecraft components. By using COTS hardware, the spacecraft program can utilize investments already made by commercial vendors. This ambitious project development philosophy/cycle has yielded the COTSAT-1 flight hardware. This paper highlights the advancements of the COTSAT-1 spacecraft leading to the delivery of the current flight hardware that is now located at NASA Ames Research Center. This paper also addresses the plans for COTSAT-2.

  2. Optimized ground-coupled heat pump system design for northern climate applications. [Including ground coil

    Energy Technology Data Exchange (ETDEWEB)

    Catan, M.A.; Baxter, V.D.

    1985-01-01

    This paper addresses the question of the performance of a ground coupled heat pump (GCHP) system with a water - source heat pump package designed expressly for such systems operating in a northern climate. The project objective was to minimize the life-cycle cost of a GCHP system by optimizing the design of both the heat pump package and the ground coil in concert. In order to achieve this objective, a number of modelling tools were developed or modified to analyze the heat pump's performance and cost and the ground coil's performance. The life-cycle cost of a GCHP system (water-source heat pump with a horizontal ground coil) for an 1800 ft/sup 2/ (167 m/sup 2/) house in Pittsburgh, PA, was minimized over a 7 year economic life. Simple payback for the optimized GCHP system, relative to conventional air-source heat pumps, was under 3 years. The water-source heat pump package resulting from this optimization is calculated to cost 21% more than its conventional counterpart with a heating coefficient of performance (COP) about 20% higher, and a cooling COP about 23% higher. In the GCHP system modeled, its annual energy savings are predicted to be about 11% compared to a system designed around the conventional heat pump while having about the same installation cost. The major conclusion of this study is - GCHP system performance improvement can be attained by improving the water-source heat pump package at less cost than by buying more ground coil. The following conclusions were drawn from the steady-state performance optimization results: (1) By adding about $100.00 to the manufacturer's cost off construction, both the heating and cooling COPs can be improved by 20% or more. (2) Cooling COP need not be sacrificed for the sake of heating performance and vice versa. 13 refs., 11 figs., 12 tabs.

  3. Maximum power, ecological function and efficiency of an irreversible Carnot cycle. A cost and effectiveness optimization

    CERN Document Server

    Aragon-Gonzalez, G; Leon-Galicia, A; Morales-Gomez, J R

    2007-01-01

    In this work we include, for the Carnot cycle, irreversibilities of linear finite rate of heat transferences between the heat engine and its reservoirs, heat leak between the reservoirs and internal dissipations of the working fluid. A first optimization of the power output, the efficiency and ecological function of an irreversible Carnot cycle, with respect to: internal temperature ratio, time ratio for the heat exchange and the allocation ratio of the heat exchangers; is performed. For the second and third optimizations, the optimum values for the time ratio and internal temperature ratio are substituted into the equation of power and, then, the optimizations with respect to the cost and effectiveness ratio of the heat exchangers are performed. Finally, a criterion of partial optimization for the class of irreversible Carnot engines is herein presented.

  4. Distribution of heating costs in multi-story apartment buildings

    DEFF Research Database (Denmark)

    Rose, Jørgen; Kragh, Jesper

    2017-01-01

    but for heating it is a much more complex issue. For instance, if a pensioner wants or needs a higher indoor temperature the expenses will become disproportionate due to heat transmission through internal walls, floors and ceilings. This is particularly pronounced in well-insulated buildings where the heat loss......Under current rules in the Danish Meter Order at least 40% of the total heating costs in multi-story blocks of flats should be distributed by metering the consumption in individual apartments. This fixed share is the result of a previous study that showed that 40% of the total heating costs were...... used for space heating, 35% for production and heat loss associated with hot water consumption and finally 25% of heat losses in the heating system. It is interesting to investigate whether this distribution remains representative in both existing buildings, where older buildings still dominate...

  5. GASIFICATION PLANT COST AND PERFORMANCE OPTIMIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Sheldon Kramer

    2003-09-01

    This project developed optimized designs and cost estimates for several coal and petroleum coke IGCC coproduction projects that produced hydrogen, industrial grade steam, and hydrocarbon liquid fuel precursors in addition to power. The as-built design and actual operating data from the DOE sponsored Wabash River Coal Gasification Repowering Project was the starting point for this study that was performed by Bechtel, Global Energy and Nexant under Department of Energy contract DE-AC26-99FT40342. First, the team developed a design for a grass-roots plant equivalent to the Wabash River Coal Gasification Repowering Project to provide a starting point and a detailed mid-year 2000 cost estimate based on the actual as-built plant design and subsequent modifications (Subtask 1.1). This non-optimized plant has a thermal efficiency to power of 38.3% (HHV) and a mid-year 2000 EPC cost of 1,681 $/kW.1 This design was enlarged and modified to become a Petroleum Coke IGCC Coproduction Plant (Subtask 1.2) that produces hydrogen, industrial grade steam, and fuel gas for an adjacent Gulf Coast petroleum refinery in addition to export power. A structured Value Improving Practices (VIP) approach was applied to reduce costs and improve performance. The base case (Subtask 1.3) Optimized Petroleum Coke IGCC Coproduction Plant increased the power output by 16% and reduced the plant cost by 23%. The study looked at several options for gasifier sparing to enhance availability. Subtask 1.9 produced a detailed report on this availability analyses study. The Subtask 1.3 Next Plant, which retains the preferred spare gasification train approach, only reduced the cost by about 21%, but it has the highest availability (94.6%) and produces power at 30 $/MW-hr (at a 12% ROI). Thus, such a coke-fueled IGCC coproduction plant could fill a near term niche market. In all cases, the emissions performance of these plants is superior to the Wabash River project. Subtasks 1.5A and B developed designs for

  6. Exergoeconomic optimization of an ammonia-water hybrid heat pump for heat supply in a spray drying facility

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars

    2014-01-01

    Spray drying facilities are among the most energy intensive industrial processes. Using a heat pump to recover waste heat and replace gas combustion has the potential to attain both economic and emissions savings. In the case examined a drying gas of ambient air is heated to 200 XC. The inlet flow...... rate is 100,000 m3/h which yields a heat load of 6.1 MW. The exhaust air from the drying process is 80 XC. The implementation of an ammonia-water hybrid absorption-compression heat pump to partly cover the heat load is investigated. A thermodynamic analysis is applied to determine optimal circulation...... ratios for a number of ammonia mass fractions and heat pump loads. An exergoeconomic optimization is applied to minimize the lifetime cost of the system. Technological limitations are applied to constrain the solution to commercial components. The best possible implementation is identified in terms...

  7. Design and economic optimization of shell and tube heat exchangers using Artificial Bee Colony (ABC) algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Sencan Sahin, Arzu, E-mail: sencan@tef.sdu.edu.tr [Department of Mechanical Education, Technical Education Faculty, Sueleyman Demirel University, 32260 Isparta (Turkey); Kilic, Bayram, E-mail: bayramkilic@hotmail.com [Bucak Emin Guelmez Vocational School, Mehmet Akif Ersoy University, Bucak (Turkey); Kilic, Ulas, E-mail: ulaskilic@mehmetakif.edu.tr [Bucak Emin Guelmez Vocational School, Mehmet Akif Ersoy University, Bucak (Turkey)

    2011-10-15

    Highlights: {yields} Artificial Bee Colony for shell and tube heat exchanger optimization is used. {yields} The total cost is minimized by varying design variables. {yields} This new approach can be applied for optimization of heat exchangers. - Abstract: In this study, a new shell and tube heat exchanger optimization design approach is developed. Artificial Bee Colony (ABC) has been applied to minimize the total cost of the equipment including capital investment and the sum of discounted annual energy expenditures related to pumping of shell and tube heat exchanger by varying various design variables such as tube length, tube outer diameter, pitch size, baffle spacing, etc. Finally, the results are compared to those obtained by literature approaches. The obtained results indicate that Artificial Bee Colony (ABC) algorithm can be successfully applied for optimal design of shell and tube heat exchangers.

  8. Entransy dissipation analysis and optimization of separated heat pipe system

    Institute of Scientific and Technical Information of China (English)

    QIAN XiaoDong; LI Zhen; MENG JiAn; LI ZhiXin

    2012-01-01

    Seperated heat pipe systems are widely used in the fields of waste heat recovery and air conditioning due to their high heat transfer capability,and optimization of heat transfer process plays an important role in high-efficiency energy utilization and energy conservation.In this paper,the entransy dissipation analysis is conducted for the separated heat pipe system,and the result indicates that minimum thermal resistance principle is applicable to the optimization of the separated heat pipe system.Whether in the applications of waste heat recovery or air conditioning,the smaller the entransy-dissipation-based thermal resistance of the separated heat pipe system is,the better the heat transfer performance will be.Based on the minimum thermal resistance principle,the optimal area allocation relationship between evaporator and condenser is deduced,which is numerically verified in the optimation design of separated heat pipe system.

  9. Thermal-economic modeling and optimization of vertical ground-coupled heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Sanaye, Sepehr; Niroomand, Behzad [Energy Systems Improvement Laboratory (ESIL), Department of Mechanical Engineering, Iran University of Science and Technology (IUST), Narmak, Tehran 16488 (Iran)

    2009-04-15

    The optimal design process of a ground source heat pump includes thermal modeling of the system and selection of optimal design parameters which affect the system performance as well as initial and operational costs. In this paper, the modeling and optimizing processes of a ground-coupled heat pump (GCHP) with closed vertical ground heat exchanger (VGHX) are presented. To verify the modeling procedure of heat pump and VGHX systems, the simulation outputs were compared with the corresponding values reported in the literature and acceptable accuracy was obtained. Then an objective function (the sum of annual operating and investment costs of the system) was defined and minimized, exposed to the specified constraints to estimate the optimum design parameters (decision variables). Two Nelder-Mead and genetic algorithm optimization techniques were applied to guarantee the validity of the optimization results. For the given heating/cooling loads and various climatic conditions, the optimum values of heat pump design parameters (saturated temperature/pressure of condenser and evaporator) as well as VGHX design parameters (inlet and outlet temperatures of the ground water source, pipe diameter, depth and number of boreholes) were predicted. Furthermore, the sensitivity analysis of change in the total annual cost of the system and optimum design parameters with the climatic conditions, cooling/heating capacity, soil type, and number of boreholes were discussed. Finally, the sensitivity analysis of change in optimum design parameters with increase in the investment and electricity costs was performed. (author)

  10. Thermoeconomic Optimization of a Combined Heating and Humidification Coil for HVAC Systems

    Science.gov (United States)

    Teodoros, Liliana; Andresen, Bjarne

    2016-07-01

    The total cost of ownership is calculated for a combined heating and humidification coil of an air-handling unit taking into account investment and operation costs simultaneously. This total cost represents the optimization function for which the minimum is sought. The parameters for the cost dependencies are the physical dimensions of the coil: length, width and height. The term "coil" is used generically since in this setup it generates heating as well as humidification in a single unit. The first part of the paper deals with the constructive optimization and finds the relationship between the dimensions for a minimum cost. The second part of the paper takes the results of the constructive optimization further and, based on the data derived in our previous papers, analyzes the minimum total cost for the humidification coil while balancing the amount of water used to humidify the air and modify its temperature.

  11. A low-computational-cost inverse heat transfer technique for convective heat transfer measurements in hypersonic flows

    Science.gov (United States)

    Avallone, F.; Greco, C. S.; Schrijer, F. F. J.; Cardone, G.

    2015-04-01

    The measurement of the convective wall heat flux in hypersonic flows may be particularly challenging in the presence of high-temperature gradients and when using high-thermal-conductivity materials. In this case, the solution of multidimensional problems is necessary, but it considerably increases the computational cost. In this paper, a low-computational-cost inverse data reduction technique is presented. It uses a recursive least-squares approach in combination with the trust-region-reflective algorithm as optimization procedure. The computational cost is reduced by performing the discrete Fourier transform on the discrete convective heat flux function and by identifying the most relevant coefficients as objects of the optimization algorithm. In the paper, the technique is validated by means of both synthetic data, built in order to reproduce physical conditions, and experimental data, carried out in the Hypersonic Test Facility Delft at Mach 7.5 on two wind tunnel models having different thermal properties.

  12. Topology optimization for nano-scale heat transfer

    DEFF Research Database (Denmark)

    Evgrafov, Anton; Maute, Kurt; Yang, Ronggui

    2009-01-01

    We consider the problem of optimal design of nano-scale heat conducting systems using topology optimization techniques. At such small scales the empirical Fourier's law of heat conduction no longer captures the underlying physical phenomena because the mean-free path of the heat carriers, phonons...

  13. Topology optimization of heat conduction problems using the finite volume method

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Allan; Bendsøe, Martin P.; Sigmund, Ole

    2006-01-01

    This note addresses the use of the finite volume method (FVM) for topology optimization of a heat conduction problem. Issues pertaining to the proper choice of cost functions, sensitivity analysis and example test problems are used to illustrate the effect of applying the FVM as an analysis tool...... checkerboards do not form during the topology optimization process....

  14. An optimized ground-coupled heat pump system design for northern climate applications

    Energy Technology Data Exchange (ETDEWEB)

    Catan, M.A.; Baxter, V.D.

    1985-01-01

    This paper addresses the question of the performance of a ground coupled heat pump (GCHP) system with a water-source heat pump package designed expressly for such systems operating in a northern climate. The project objective was to minimize the life-cycle cost of a GCHP system by optimizing the design of both the heat pump package and the group coil in concert. In order to achieve this objective, a number of modelling tools were developed to analyze the heat pump's performance and cost, and the ground coil's performance.

  15. Thermal-economic multi-objective optimization of shell and tube heat exchanger using particle swarm optimization (PSO)

    Science.gov (United States)

    Ghanei, A.; Assareh, E.; Biglari, M.; Ghanbarzadeh, A.; Noghrehabadi, A. R.

    2014-10-01

    Many studies are performed by researchers about shell and tube heat exchanger (STHE) but the multi-objective particle swarm optimization (PSO) technique has never been used in such studies. This paper presents application of thermal-economic multi-objective optimization of STHE using PSO. For optimal design of a STHE, it was first thermally modeled using e-number of transfer units method while Bell-Delaware procedure was applied to estimate its shell side heat transfer coefficient and pressure drop. Multi objective PSO (MOPSO) method was applied to obtain the maximum effectiveness (heat recovery) and the minimum total cost as two objective functions. The results of optimal designs were a set of multiple optimum solutions, called `Pareto optimal solutions'. In order to show the accuracy of the algorithm, a comparison is made with the non-dominated sorting genetic algorithm (NSGA-II) and MOPSO which are developed for the same problem.

  16. evaluation of total annual costs of heat exchanger networks using ...

    African Journals Online (AJOL)

    This study presents pinch analysis of some heat exchanger networks (HENs) problems using Hint integration (HINT) software. ... and the general optimization of the networks for minimum TAC for the three problems solved. ... Article Metrics.

  17. Introducing cost-optimal levels for energy requirements

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne; Thomsen, Kirsten Engelund

    2012-01-01

    The recast of the Directive on the Energy Performance of Buildings (EPBD) states that Member States (MS) must ensure that minimum energy performance requirements for buildings are set “with a view to achieve cost-optimal levels”, and that the cost-optimal level must be calculated in accordance...... with a comparative methodology. The ultimate goal of this is to achieve a cost-optimal improvement of buildings’ energy performance (new and existing) in reality....

  18. METHODS FOR DETERMINATION AND OPTIMIZATION OF LOGISTICS COSTS

    OpenAIRE

    Mihaela STET

    2016-01-01

    The paper is dealing with the problems of logistics costs, highlighting some methods for estimation and determination of specific costs for different transport modes in freight distribution. There are highlighted, besides costs of transports, the other costs in supply chain, as well as costing methods used in logistics activities. In this context, there are also revealed some optimization means of transport costs in logistics chain.

  19. A Fully Developed Flow Thermofluid Model for Topology Optimization of 3D-Printed Air-Cooled Heat Exchangers

    DEFF Research Database (Denmark)

    Haertel, Jan Hendrik Klaas; Nellis, Gregory F.

    2017-01-01

    . The conductance of the heat exchanger is maximized for a prescribed pressure drop and prescribed air-side temperature change across the heat exchanger. Polymer with infilled thermally conducting metal filaments is considered as the heat exchanger material which allows cost effective additive manufacturing...... optimized slot channel model in order to demonstrate the superior performance of the topology optimized designs. Thus, this work demonstrates the usefulness of topology optimization to fully exploit the design freedom afforded by additive manufacturing technologies....

  20. Optimal pricing decision model based on activity-based costing

    Institute of Scientific and Technical Information of China (English)

    王福胜; 常庆芳

    2003-01-01

    In order to find out the applicability of the optimal pricing decision model based on conventional costbehavior model after activity-based costing has given strong shock to the conventional cost behavior model andits assumptions, detailed analyses have been made using the activity-based cost behavior and cost-volume-profitanalysis model, and it is concluded from these analyses that the theory behind the construction of optimal pri-cing decision model is still tenable under activity-based costing, but the conventional optimal pricing decisionmodel must be modified as appropriate to the activity-based costing based cost behavior model and cost-volume-profit analysis model, and an optimal pricing decision model is really a product pricing decision model construc-ted by following the economic principle of maximizing profit.

  1. An optimal promotion cost control model for a markovian manpower ...

    African Journals Online (AJOL)

    An optimal promotion cost control model for a markovian manpower system. ... Log in or Register to get access to full text downloads. ... A theory concerning the existence of an optimal promotion control strategy for controlling a Markovian ...

  2. Heat savings and heat generation technologies: Modelling of residential investment behaviour with local health costs

    DEFF Research Database (Denmark)

    Zvingilaite, Erika; Klinge Jacobsen, Henrik

    2015-01-01

    their primary heating source with secondary heating e.g. a woodstove. This choice results in increased indoor air pollution with fine particles causing health effects. We integrate health cost due to use of woodstoves into household optimisation of heating expenditures. The results show that due...... for private consumers decrease by 66% when all have the option to shift to the technology with lowest variable costs. © 2014 Elsevier Ltd. All Rights reserved...

  3. Least dissipation principle of heat transport potential capacity and its application in heat conduction optimization

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In the viewpoint of heat transfer, heat transport potential capacity and its dissipation are defined based on the essence of heat transport phenomenon. Respectively, their physical meanings are the overall heat transfer capabilityand the dissipation rate of the heat transfer capacity. Then the least dissipation principle of heat transport potential capacity is presented to enhance the heat conduction efficiency in the heat conduction optimization. The principle is,for a conduction process with the constant integral of the thermal conductivityover the region, the optimal distribution of thermal conductivity, which corresponds to the highest heat conduction efficiency, is characterized by the least dissipation of heat transport potential capacity. Finally the principle is applied to some cases in heat conduction optimization.

  4. Optimal Control of Non-well-posed Heat Equations

    Institute of Scientific and Technical Information of China (English)

    Geng Sheng WANG

    2005-01-01

    This work is concerned with Pontryagin's maximum principle of optimal control problems governed by some non-well-posed semilinear heat equations. A type of approach to the non-well-posed optimal control problem is given.

  5. Thermal-economic multiobjective optimization of heat pipe heat exchanger for energy recovery in HVAC applications using genetic algorithm

    Directory of Open Access Journals (Sweden)

    Sanaye Sepehr

    2014-01-01

    Full Text Available Cost and effectiveness are two important factors of heat pipe heat exchanger (HPHE design. The total cost includes the investment cost for buying equipment (heat exchanger surface area and operating cost for energy expenditures (related to fan power. The HPHE was thermally modeled using e-NTU method to estimate the overall heat transfer coefficient for the bank of finned tubes as well as estimating pressure drop. Fast and elitist non-dominated sorting genetic algorithm (NSGA-II with continuous and discrete variables was applied to obtain the maximum effectiveness and the minimum total cost as two objective functions. Pipe diameter, pipe length, numbers of pipes per row, number of rows, fin pitch and fin length ratio were considered as six design parameters. The results of optimal designs were a set of multiple optimum solutions, called ‘Pareto optimal solutions’. The comparison of the optimum values of total cost and effectiveness, variation of optimum values of design parameters as well as estimating the payback period were also reported for various inlet fresh air volume flow rates.

  6. Optimization of Serial Combined System of Ground-Coupled Heat Pump and Solar Collector

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun; CHEN Yan; LU Suzhen; CUI Junkui

    2009-01-01

    A mathematical optimization model was set up for a ground-solar combined system based on in-situ experimental results,in which the solar collector was combined serially with a ground-coupled heat pump(GCHP).The universal optimal equations were solved by the constrained variable metric method considering both the performance and economics.Then the model was applied to a specific case concerning an actual solar assisted GCHP system for space heating.The results indicated a system coefficient of performance(COP)of 3.9 for the optimal method under the seriaI heating mode,and 3.2 for the conventional one.In addition,the optimum solution also showed advantages in energy and cost saving.1eading to a 16.7%improvement in the heat pump performance at 17.2%less energy consumption and 11.8%lower annual cost,respectively.

  7. Low Cost Polymer heat Exchangers for Condensing Boilers

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, Thomas [Brookhaven National Lab. (BNL), Upton, NY (United States); Trojanowski, Rebecca [Brookhaven National Lab. (BNL), Upton, NY (United States); Wei, George [Brookhaven National Lab. (BNL), Upton, NY (United States); Worek, Michael [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-09-30

    Work in this project sought to develop a suitable design for a low cost, corrosion resistant heat exchanger as part of a high efficiency condensing boiler. Based upon the design parameters and cost analysis several geometries and material options were explored. The project also quantified and demonstrated the durability of the selected polymer/filler composite under expected operating conditions. The core material idea included a polymer matrix with fillers for thermal conductivity improvement. While the work focused on conventional heating oil, this concept could also be applicable to natural gas, low sulfur heating oil, and biodiesel- although these are considered to be less challenging environments. An extruded polymer composite heat exchanger was designed, built, and tested during this project, demonstrating technical feasibility of this corrosion-resistant material approach. In such flue gas-to-air heat exchangers, the controlling resistance to heat transfer is in the gas-side convective layer and not in the tube material. For this reason, the lower thermal conductivity polymer composite heat exchanger can achieve overall heat transfer performance comparable to a metal heat exchanger. However, with the polymer composite, the surface temperature on the gas side will be higher, leading to a lower water vapor condensation rate.

  8. Use of Algorithm of Changes for Optimal Design of Heat Exchanger

    Science.gov (United States)

    Tam, S. C.; Tam, H. K.; Chio, C. H.; Tam, L. M.

    2010-05-01

    For economic reasons, the optimal design of heat exchanger is required. Design of heat exchanger is usually based on the iterative process. The design conditions, equipment geometries, the heat transfer and friction factor correlations are totally involved in the process. Using the traditional iterative method, many trials are needed for satisfying the compromise between the heat exchange performance and the cost consideration. The process is cumbersome and the optimal design is often depending on the design engineer's experience. Therefore, in the recent studies, many researchers, reviewed in [1], applied the genetic algorithm (GA) [2] for designing the heat exchanger. The results outperformed the traditional method. In this study, the alternative approach, algorithm of changes, is proposed for optimal design of shell-tube heat exchanger [3]. This new method, algorithm of changes based on I Ching (???), is developed originality by the author. In the algorithms, the hexagram operations in I Ching has been generalized to binary string case and the iterative procedure which imitates the I Ching inference is also defined. On the basis of [3], the shell inside diameter, tube outside diameter, and baffles spacing were treated as the design (or optimized) variables. The cost of the heat exchanger was arranged as the objective function. Through the case study, the results show that the algorithm of changes is comparable to the GA method. Both of method can find the optimal solution in a short time. However, without interchanging information between binary strings, the algorithm of changes has advantage on parallel computation over GA.

  9. Life Cycle Cost optimization of a BOLIG+ Zero Energy Building

    Energy Technology Data Exchange (ETDEWEB)

    Marszal, A.J.

    2011-12-15

    -connected ZEBs - Net ZEBs, and the annual primary energy balance. The Life Cycle Cost (LCC) analysis conducted with a study case of a multi-storey residential Net ZEB aimed to determine the cost-optimal ''zero'' energy balance, minimum energy performance requirements and options of supplying renewable energy. The calculation encompassed three levels of energy frames, which mirrored the Danish low-energy building classes included in the current building code, and ten renewable energy supply systems including both on-site and off-site options. The results indicated that although the off-site options have lower life cycle costs than the on-site alternatives, their application would promote renewable technologies over energy efficiency measures. Thus, they oppose the Danish plans to gradually make the energy performance requirements stricter. Moreover, the results showed that district heating is a less cost-attractive solution than a ground source heat pump for a private building owner. Finally, with 2010-level of energy prices, cost-optimal ''zero'' energy balance accounts only for the building related energy use. (Author)

  10. Introducing cost-optimal levels for energy requirements

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne; Thomsen, Kirsten Engelund

    2012-01-01

    The recast of the Directive on the Energy Performance of Buildings (EPBD) states that Member States (MS) must ensure that minimum energy performance requirements for buildings are set “with a view to achieve cost-optimal levels”, and that the cost-optimal level must be calculated in accordance wi...

  11. Cost-optimal levels for energy performance requirements

    DEFF Research Database (Denmark)

    Thomsen, Kirsten Engelund; Aggerholm, Søren; Kluttig-Erhorn, Heike

    2011-01-01

    The CA conducted a study on experiences and challenges for setting cost optimal levels for energy performance requirements. The results were used as input by the EU Commission in their work of establishing the Regulation on a comparative methodology framework for calculating cost optimal levels o...

  12. Objective function for municipal heat supply systems’ structural optimization

    Directory of Open Access Journals (Sweden)

    Sergiy V. Babich

    2015-03-01

    Full Text Available Modern heat supply systems in urban areas have the potential to heat supply cost reduction when using various alternative thermal energy sources. Availability of possible alternatives allows to select the source that generates a cheaper heat. At that arises the question of expressing such different sources’ characteristics as capital cost, reliability and efficiency in the consistent measurement units. This paper proposes an objective function representing all the factors affecting the thermal energy final cost in monetary units. It is shown that depending on external factors the range of prime cost for heat from various sources does vary considerably. Expected is that the proposed objective function application for managing the heat supply systems structure in urban areas will significantly reduce the operating costs.

  13. Adjoint optimization of natural convection problems: differentially heated cavity

    Science.gov (United States)

    Saglietti, Clio; Schlatter, Philipp; Monokrousos, Antonios; Henningson, Dan S.

    2016-06-01

    Optimization of natural convection-driven flows may provide significant improvements to the performance of cooling devices, but a theoretical investigation of such flows has been rarely done. The present paper illustrates an efficient gradient-based optimization method for analyzing such systems. We consider numerically the natural convection-driven flow in a differentially heated cavity with three Prandtl numbers (Pr=0.15{-}7 ) at super-critical conditions. All results and implementations were done with the spectral element code Nek5000. The flow is analyzed using linear direct and adjoint computations about a nonlinear base flow, extracting in particular optimal initial conditions using power iteration and the solution of the full adjoint direct eigenproblem. The cost function for both temperature and velocity is based on the kinetic energy and the concept of entransy, which yields a quadratic functional. Results are presented as a function of Prandtl number, time horizons and weights between kinetic energy and entransy. In particular, it is shown that the maximum transient growth is achieved at time horizons on the order of 5 time units for all cases, whereas for larger time horizons the adjoint mode is recovered as optimal initial condition. For smaller time horizons, the influence of the weights leads either to a concentric temperature distribution or to an initial condition pattern that opposes the mean shear and grows according to the Orr mechanism. For specific cases, it could also been shown that the computation of optimal initial conditions leads to a degenerate problem, with a potential loss of symmetry. In these situations, it turns out that any initial condition lying in a specific span of the eigenfunctions will yield exactly the same transient amplification. As a consequence, the power iteration converges very slowly and fails to extract all possible optimal initial conditions. According to the authors' knowledge, this behavior is illustrated here

  14. District Heating Network Design and Configuration Optimization with Genetic Algorithm

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    2011-01-01

    the heating plant location is allowed to vary. The connection between the heat generation plant and the end users can be represented with mixed integer and the pipe friction and heat loss formulations are non-linear. In order to find the optimal DH distribution pipeline configuration, the genetic algorithm...

  15. Optimal Day-to-Night Greenhouse Heat Storage

    NARCIS (Netherlands)

    Seginer, Ido; Straten, van Gerrit; Beveren, van Peter

    2016-01-01

    Day-to-night heat storage is often practiced in cold-climate greenhouses. It is suggested to manage the heat storage by considering the co-state (virtual value) of the stored heat in the on-line optimization of the greenhouse environment. Examples worked out for a periodic square-wave weather show t

  16. District Heating Network Design and Configuration Optimization with Genetic Algorithm

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    2011-01-01

    the heating plant location is allowed to vary. The connection between the heat generation plant and the end users can be represented with mixed integer and the pipe friction and heat loss formulations are non-linear. In order to find the optimal DH distribution pipeline configuration, the genetic algorithm...

  17. Optimization of a Finned Shell and Tube Heat Exchanger Using a Multi-Objective Optimization Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Heidar Sadeghzadeh

    2015-08-01

    Full Text Available Heat transfer rate and cost significantly affect designs of shell and tube heat exchangers. From the viewpoint of engineering, an optimum design is obtained via maximum heat transfer rate and minimum cost. Here, an analysis of a radial, finned, shell and tube heat exchanger is carried out, considering nine design parameters: tube arrangement, tube diameter, tube pitch, tube length, number of tubes, fin height, fin thickness, baffle spacing ratio and number of fins per unit length of tube. The “Delaware modified” technique is used to determine heat transfer coefficients and the shell-side pressure drop. In this technique, the baffle cut is 20 percent and the baffle ratio limits range from 0.2 to 0.4. The optimization of the objective functions (maximum heat transfer rate and minimum total cost is performed using a non-dominated sorting genetic algorithm (NSGA-II, and compared against a one-objective algorithm, to find the best solutions. The results are depicted as a set of solutions on a Pareto front, and show that the heat transfer rate ranges from 3517 to 7075 kW. Also, the minimum and maximum objective functions are specified, allowing the designer to select the best points among these solutions based on requirements. Additionally, variations of shell-side pressure drop with total cost are depicted, and indicate that the pressure drop ranges from 3.8 to 46.7 kPa.

  18. The optimization of Stirling refrigerator and Stirling heat engine

    Science.gov (United States)

    Zhu, Xin-Mei

    2007-03-01

    The optimization of an irreversible Stirling refrigerator or a Stirling heat engine is an important research subject for a long time. Taking into account of the influence of mixed thermal resistance and regeneration loss in the performance study, we have derived the optimal relation of both of them. For Stirling refrigerator, we have deduced the optimal relation between the thermal resistance coefficient and the efficiency. To the Stirling heat engine, we have deduced the optimal relation between the power output and the efficiency. The conclusions obtained mirror the observed performance of the Stirling refrigerator or the Stirling heat engine quite well. Thus, the results may provide a new theoretical guidance to the optimal design and the selection of optimal operating condition of the Stirling refrigerator or the Stirling heat engine.

  19. Method for optimal design of pipes for low-energy district heating, with focus on heat losses

    DEFF Research Database (Denmark)

    Dalla Rosa, Alessandro; Li, Hongwei; Svendsen, Svend

    2011-01-01

    The synergy between highly energy-efficient buildings and low-energy district heating (DH) systems is a promising concept for the optimal integration of energy-saving policies and energy supply systems based on renewable energy (RE). Network transmission and distribution heat loss is one of the key...... factors in the optimal design of low-energy DH systems. Various pipe configurations are considered in this paper: flexible pre-insulated twin pipes with symmetrical or asymmetrical insulation, double pipes, and triple pipes. These technologies represent potential energy-efficient and cost...... showed the influence of the soil temperature throughout the year. Finally, the article describes proposals for the optimal design of pipes for low-energy applications and presents methods for decreasing heat losses....

  20. Finite-Time Thermoeconomic Optimization of a Solar-Driven Heat Engine Model

    Directory of Open Access Journals (Sweden)

    Fernando Angulo-Brown

    2011-01-01

    Full Text Available In the present paper, the thermoeconomic optimization of an irreversible solar-driven heat engine model has been carried out by using finite-time/finite-size thermodynamic theory. In our study we take into account losses due to heat transfer across finite time temperature differences, heat leakage between thermal reservoirs and internal irreversibilities in terms of a parameter which comes from the Clausius inequality. In the considered heat engine model, the heat transfer from the hot reservoir to the working fluid is assumed to be Dulong-Petit type and the heat transfer to the cold reservoir is assumed of the Newtonian type. In this work, the optimum performance and two design parameters have been investigated under two objective functions: the power output per unit total cost and the ecological function per unit total cost. The effects of the technical and economical parameters on the thermoeconomic performance have been also discussed under the aforementioned two criteria of performance.

  1. Optimal Joint Liability Lending and with Costly Peer Monitoring

    NARCIS (Netherlands)

    Carli, F.; Uras, R.B.

    2014-01-01

    This paper characterizes an optimal group loan contract with costly peer monitoring. Using a fairly standard moral hazard framework, we show that the optimal group lending contract could exhibit a joint-liability scheme. However, optimality of joint-liability requires the involvement of a group lead

  2. Low-Cost Solar Water Heating Research and Development Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Hudon, K.; Merrigan, T.; Burch, J.; Maguire, J.

    2012-08-01

    The market environment for solar water heating technology has changed substantially with the successful introduction of heat pump water heaters (HPWHs). The addition of this energy-efficient technology to the market increases direct competition with solar water heaters (SWHs) for available energy savings. It is therefore essential to understand which segment of the market is best suited for HPWHs and focus the development of innovative, low-cost SWHs in the market segment where the largest opportunities exist. To evaluate cost and performance tradeoffs between high performance hot water heating systems, annual energy simulations were run using the program, TRNSYS, and analysis was performed to compare the energy savings associated with HPWH and SWH technologies to conventional methods of water heating.

  3. Exploiting cost distributions for query optimization

    NARCIS (Netherlands)

    Waas, F.; Pellenkoft, A.J.

    1998-01-01

    Large-scale query optimization is, besides its practical relevance, a hard test case for optimization techniques. Since exact methods cannot be applied due to the combinatorial explosion of the search space, heuristics and probabilistic strategies have been deployed for more than a decade. However,

  4. Optimization of Composition and Heat Treating of Die Steels for Extended Lifetime

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Quanyou Zhou

    2002-01-30

    An ''average'' die casting die costs fifty thousand dollars. A die used in making die cast aluminum engine blocks can cost well over one million dollars. These costs provide a strong incentive for extension of die life. While vacuum quenched Premium Grade H13 dies have become the most widely used in the United States, tool makers and die casters are constantly searching for new steels and heat treating procedures to extend die life. This project was undertaken to investigate the effects of composition and heat treating on die life and optimize these parameters.

  5. Pipeline heating method based on optimal control and state estimation

    Energy Technology Data Exchange (ETDEWEB)

    Vianna, F.L.V. [Dept. of Subsea Technology. Petrobras Research and Development Center - CENPES, Rio de Janeiro, RJ (Brazil)], e-mail: fvianna@petrobras.com.br; Orlande, H.R.B. [Dept. of Mechanical Engineering. POLI/COPPE, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ (Brazil)], e-mail: helcio@mecanica.ufrj.br; Dulikravich, G.S. [Dept. of Mechanical and Materials Engineering. Florida International University - FIU, Miami, FL (United States)], e-mail: dulikrav@fiu.edu

    2010-07-01

    In production of oil and gas wells in deep waters the flowing of hydrocarbon through pipeline is a challenging problem. This environment presents high hydrostatic pressures and low sea bed temperatures, which can favor the formation of solid deposits that in critical operating conditions, as unplanned shutdown conditions, may result in a pipeline blockage and consequently incur in large financial losses. There are different methods to protect the system, but nowadays thermal insulation and chemical injection are the standard solutions normally used. An alternative method of flow assurance is to heat the pipeline. This concept, which is known as active heating system, aims at heating the produced fluid temperature above a safe reference level in order to avoid the formation of solid deposits. The objective of this paper is to introduce a Bayesian statistical approach for the state estimation problem, in which the state variables are considered as the transient temperatures within a pipeline cross-section, and to use the optimal control theory as a design tool for a typical heating system during a simulated shutdown condition. An application example is presented to illustrate how Bayesian filters can be used to reconstruct the temperature field from temperature measurements supposedly available on the external surface of the pipeline. The temperatures predicted with the Bayesian filter are then utilized in a control approach for a heating system used to maintain the temperature within the pipeline above the critical temperature of formation of solid deposits. The physical problem consists of a pipeline cross section represented by a circular domain with four points over the pipe wall representing heating cables. The fluid is considered stagnant, homogeneous, isotropic and with constant thermo-physical properties. The mathematical formulation governing the direct problem was solved with the finite volume method and for the solution of the state estimation problem

  6. Optimizing the District Heating Primary Network from the Perspective of Economic-Specific Pressure Loss

    Directory of Open Access Journals (Sweden)

    Haichao Wang

    2017-07-01

    Full Text Available A district heating (DH system is one of the most important components of infrastructures in cold areas. Proper DH network design should balance the initial investment and the heat distribution cost of the DH network. Currently, this design is often based on a recommended value for specific pressure loss (R = ∆P/L in the main lines. This will result in a feasible network design, but probably not be optimal in most cases. The paper develops a novel optimization model to facilitate the design by considering the initial investment in the pipes and the heat distribution costs. The model will generate all possible network scenarios consisting of different series of diameters for each pipe in the flow direction of the network. Then, the annuity on the initial investment, the heat distribution cost, and the total annual cost will be calculated for each network scenario, taking into account the uncertainties of the material prices and the yearly operating time levels. The model is applied to a sample DH network and the results indicate that the model works quite well, clearly identifying the optimal network design and demonstrating that the heat distribution cost is more important than the initial investment in DH network design.

  7. Constructs of highly effective heat transport paths by bionic optimization

    Institute of Scientific and Technical Information of China (English)

    CHENG; Xinguang; (程新广); LI; Zhixin; (李志信); GUO; Zengyuan; (过增元)

    2003-01-01

    The optimization approach based on the biological evolution principle is used to construct the heat transport paths for volume-to-point problem. The transport paths are constructed by inserting high conductivity materials in the heat conduction domain where uniform or nonuniform heat sources exist. In the bionic optimization process, the optimal constructs of the high conductivity material are obtained by numerically simulating the evolution and degeneration process according to the uniformity principle of the temperature gradient. Finally, preserving the features of the optimal constructs, the constructs are regularized for the convenience of engineering manufacture. The results show that the construct obtained by bionic optimization is approximate to that obtained by the tree-network constructal theory when the heat conduction is enhanced for the domain with a uniform heat source and high conductivity ratio of the inserting material to the substrate, the high conductivity materials are mainly concentrated on the heat outlet for the case with a uniform heat source and low thermal conductivity ratio, and for the case with nonuniform heat sources, the high conductivity material is concentrated in the heat source regions and construacts several highly effective heat transport paths to connect the regions to the outlet.

  8. Optimization for entransy dissipation minimization in heat exchanger

    Institute of Scientific and Technical Information of China (English)

    XIA ShaoJun; CHEN LinGen; SUN FengRui

    2009-01-01

    A common of two-fluid flow heat exchanger, in which the heat transfer between high-and low-temperature sides obeys Newton's law [q∝△(T)], is studied in this paper. By taking entransy dissipation minimization as optimization objective, the optimum parameter distributions in the heat ex-changer are derived by using optimal control theory under the condition of fixed heat load. The condition corresponding to the minimum entransy dissipation is that corresponding to a constant heat flux density. Three kinds of heat exchangers, including parallel flow, condensing flow and counter-flow, are considered, and the results show that only the counter-flow heat exchanger can realize the entransy dissipation minimization in the heat transfer process. The obtained results for entransy dissipation minimization are also compared with those obtained for entropy generation minimization by numerical examples.

  9. Optimization principle of operating parameters of heat exchanger by using CFD simulation

    Science.gov (United States)

    Mičieta, Jozef; Jiří, Vondál; Jandačka, Jozef; Lenhard, Richard

    2016-03-01

    Design of effective heat transfer devices and minimizing costs are desired sections in industry and they are important for both engineers and users due to the wide-scale use of heat exchangers. Traditional approach to design is based on iterative process in which is gradually changed design parameters, until a satisfactory solution is achieved. The design process of the heat exchanger is very dependent on the experience of the engineer, thereby the use of computational software is a major advantage in view of time. Determination of operating parameters of the heat exchanger and the subsequent estimation of operating costs have a major impact on the expected profitability of the device. There are on the one hand the material and production costs, which are immediately reflected in the cost of device. But on the other hand, there are somewhat hidden costs in view of economic operation of the heat exchanger. The economic balance of operation significantly affects the technical solution and accompanies the design of the heat exchanger since its inception. Therefore, there is important not underestimate the choice of operating parameters. The article describes an optimization procedure for choice of cost-effective operational parameters for a simple double pipe heat exchanger by using CFD software and the subsequent proposal to modify its design for more economical operation.

  10. Optimization principle of operating parameters of heat exchanger by using CFD simulation

    Directory of Open Access Journals (Sweden)

    Mičieta Jozef

    2016-01-01

    Full Text Available Design of effective heat transfer devices and minimizing costs are desired sections in industry and they are important for both engineers and users due to the wide-scale use of heat exchangers. Traditional approach to design is based on iterative process in which is gradually changed design parameters, until a satisfactory solution is achieved. The design process of the heat exchanger is very dependent on the experience of the engineer, thereby the use of computational software is a major advantage in view of time. Determination of operating parameters of the heat exchanger and the subsequent estimation of operating costs have a major impact on the expected profitability of the device. There are on the one hand the material and production costs, which are immediately reflected in the cost of device. But on the other hand, there are somewhat hidden costs in view of economic operation of the heat exchanger. The economic balance of operation significantly affects the technical solution and accompanies the design of the heat exchanger since its inception. Therefore, there is important not underestimate the choice of operating parameters. The article describes an optimization procedure for choice of cost-effective operational parameters for a simple double pipe heat exchanger by using CFD software and the subsequent proposal to modify its design for more economical operation.

  11. Optimization of life cycle management costs

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, A.K. [Stone & Webster Engineering Corp., Boston, MA (United States)

    1994-12-31

    As can be seen from the case studies, a LCM program needs to address and integrate, in the decision process, technical, political, licensing, remaining plant life, component replacement cycles, and financial issues. As part of the LCM evaluations, existing plant programs, ongoing replacement projects, short and long-term operation and maintenance issues, and life extension strategies must be considered. The development of the LCM evaluations and the cost benefit analysis identifies critical technical and life cycle cost parameters. These {open_quotes}discoveries{close_quotes} result from the detailed and effective use of a consistent, quantifiable, and well documented methodology. The systematic development and implementation of a plant-wide LCM program provides for an integrated and structured process that leads to the most practical and effective recommendations. Through the implementation of these recommendations and cost effective decisions, the overall power production costs can be controlled and ultimately lowered.

  12. Synthesis and Stochastic Assessment of Cost-Optimal Schedules

    OpenAIRE

    Mader, A.H.; Bohnenkamp, H.C.; Usenko, Y.S.; Jansen, D.N.; J L Hurink; Hermanns, H.

    2006-01-01

    We treat the problem of generating cost-optimal schedules for orders with individual due dates and cost functions based on earliness/tardiness. Orders can run in parallel in a resource-constrained manufacturing environment, where resources are subject to stochastic breakdowns. The goal is to generate schedules while minimizing the expected costs. First, we estimate the distribution of each order type by simulation (assuming a reasonable machine/load model) and derive from the cost-function an...

  13. Co-optimized design of microchannel heat exchangers and thermoelectric generators

    DEFF Research Database (Denmark)

    Kolaei, Alireza Rezania; Yazawa, K.; Rosendahl, Lasse;

    2013-01-01

    Designs of heat exchangers have mostly been disconnected to the performance of thermoelectric generator (TEG) systems. The development work, mostly focused on thermoelectric materials, required a significant amount of engineering parametric analysis. In this work, a micro plate-fin heat exchanger...... applied to a TEG is investigated and optimized to maximize the output power and the cost performance of generic TEG systems. The cost per performance is counted by a measure of price per power output ($/W). The channel width, channel height, fin thickness of heat exchanger, and fill factor of TEG...... are theoretically optimized for a wide range of pumping power. In conjunction with effective numeric tests, the model discusses the optimum size of the system components’ dimensions at two area sizes of the substrate plate of heat exchanger. Results show that at every pumping power, there are particular values...

  14. Optimization of the Single Staggered Wire and Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Arsana I Made

    2016-01-01

    Full Text Available Wire and tube heat exchanger consists of a coiled tube, and wire is welded on the two sides of it in normal direction of the tube. Generally,wire and tube heat exchanger uses inline wire arrangement between the two sides, whereas in this study, it used staggered wire arrangement that reduces the restriction of convection heat transfer. This study performed the optimization of single staggered wire and tube heat exchanger to increase the capacity and reduce the mass of the heat exchanger. Optimization was conducted with the Hooke-Jeeves method, which aims to optimize the geometry of the heat exchanger, especially on the diameter (dw and the distance between wires (pw. The model developed to present heat transfer correlations on single staggered wire and tube heat exchanger was valid. The maximum optimization factor obtained when the diameter wire was 0.9 mm and the distance between wires (pw was 11 mm with the fref value = 1.5837. It means that the optimized design only using mass of 59,10 % and could transfer heat about 98,5 % from the basis design.

  15. Optimizing Data Centre Energy and Environmental Costs

    Science.gov (United States)

    Aikema, David Hendrik

    Data centres use an estimated 2% of US electrical power which accounts for much of their total cost of ownership. This consumption continues to grow, further straining power grids attempting to integrate more renewable energy. This dissertation focuses on assessing and reducing data centre environmental and financial costs. Emissions of projects undertaken to lower the data centre environmental footprints can be assessed and the emission reduction projects compared using an ISO-14064-2-compliant greenhouse gas reduction protocol outlined herein. I was closely involved with the development of the protocol. Full lifecycle analysis and verifying that projects exceed business-as-usual expectations are addressed, and a test project is described. Consuming power when it is low cost or when renewable energy is available can be used to reduce the financial and environmental costs of computing. Adaptation based on the power price showed 10--50% potential savings in typical cases, and local renewable energy use could be increased by 10--80%. Allowing a fraction of high-priority tasks to proceed unimpeded still allows significant savings. Power grid operators use mechanisms called ancillary services to address variation and system failures, paying organizations to alter power consumption on request. By bidding to offer these services, data centres may be able to lower their energy costs while reducing their environmental impact. If providing contingency reserves which require only infrequent action, savings of up to 12% were seen in simulations. Greater power cost savings are possible for those ceding more control to the power grid operator. Coordinating multiple data centres adds overhead, and altering at which data centre requests are processed based on changes in the financial or environmental costs of power is likely to increase this overhead. Tests of virtual machine migrations showed that in some cases there was no visible increase in power use while in others power use

  16. Electricity Market Optimization of Heat Pump Portfolio

    DEFF Research Database (Denmark)

    Biegel, Benjamin; Andersen, Palle; Pedersen, Tom S.

    2013-01-01

    We consider a portfolio of domestic heat pumps controlled by an aggregator. The aggregator is able to adjust the consumption of the heat pumps without affecting the comfort in the houses and uses this ability to shift the main consumption to hours with low electricity prices. Further, the aggrega......We consider a portfolio of domestic heat pumps controlled by an aggregator. The aggregator is able to adjust the consumption of the heat pumps without affecting the comfort in the houses and uses this ability to shift the main consumption to hours with low electricity prices. Further...

  17. Life Cycle Cost Optimization of a Bolig+ Zero Energy Building

    DEFF Research Database (Denmark)

    Marszal, Anna Joanna

    included in the current building code, and ten renewable energy supply systems including both on-site and off-site options. Theresults indicated that although the off-site options have lower life cycle costs than the on-site alternatives, their application would promote renewable technologies overenergy......, cost-optimal “zero” energybalance accounts only for the building related energy use....... owners’ approach to it. For thisparticular target group, the cost is often an obstacle when investing money in environmental or climate friendly products. Therefore, this PhD project took theperspective of a future private ZEB owner to investigate the cost-optimal Net ZEB definition applicable...

  18. Cost Optimizations in Runtime Testing and Diagnosis

    NARCIS (Netherlands)

    Gonzalez Sanchez, A.

    2011-01-01

    Software testing and diagnosis (debugging) is a time-consuming but rather important task for improving software reliability. It is therefore necessary to devise an appropriate verification strategy that not only achieves this reliability goal, but also does this at a minimum cost. Since exhaustive

  19. Cost Optimizations in Runtime Testing and Diagnosis

    NARCIS (Netherlands)

    Gonzalez Sanchez, A.

    2011-01-01

    Software testing and diagnosis (debugging) is a time-consuming but rather important task for improving software reliability. It is therefore necessary to devise an appropriate verification strategy that not only achieves this reliability goal, but also does this at a minimum cost. Since exhaustive

  20. Optimal Operation of the Integrated Electrical and Heating Systems to Accommodate the Intermittent Renewable Sources

    DEFF Research Database (Denmark)

    Li, Jinghua; Fang, Jiakun; Zeng, Qing

    2016-01-01

    The integration of electrical and heating systems has great potential to enhance the flexibility of power systems to accommodate more renewable power such as the wind and solar. This study was to investigate an optimal way to integrate the energy of both systems in urban areas. The amount of energy...... conversion between the electrical system and heating system was optimally decided so that the demand within both systems could be met at the least operational cost. Besides, the best node to join with the electrical system and heating system was chosen by consideration of the energy transmission loss....... The mathematic formulation of the optimization problem was detailed as a large-scale non-linear program (LSNLP) in this paper. A decomposition-coordination algorithm was proposed to solve this LSNLP. At last, a 6-bus electrical power system with 31-node heating transmission system was studied to demonstrate...

  1. Application of particle swarm optimization algorithm in the heating system planning problem.

    Science.gov (United States)

    Ma, Rong-Jiang; Yu, Nan-Yang; Hu, Jun-Yi

    2013-01-01

    Based on the life cycle cost (LCC) approach, this paper presents an integral mathematical model and particle swarm optimization (PSO) algorithm for the heating system planning (HSP) problem. The proposed mathematical model minimizes the cost of heating system as the objective for a given life cycle time. For the particularity of HSP problem, the general particle swarm optimization algorithm was improved. An actual case study was calculated to check its feasibility in practical use. The results show that the improved particle swarm optimization (IPSO) algorithm can more preferably solve the HSP problem than PSO algorithm. Moreover, the results also present the potential to provide useful information when making decisions in the practical planning process. Therefore, it is believed that if this approach is applied correctly and in combination with other elements, it can become a powerful and effective optimization tool for HSP problem.

  2. Optimal Placement of A Heat Pump in An Integrated Power and Heat Energy System

    DEFF Research Database (Denmark)

    Klyapovskiy, Sergey; You, Shi; Bindner, Henrik W.

    2017-01-01

    pump – a component that links electric and heating utilities together. The system used to demonstrate the integrated planning approach has two neighboring 10kV feeders and several distribution substations with loads that require central heating from the heat pump. The optimal location is found......With the present trend towards Smart Grids and Smart Energy Systems it is important to look for the opportunities for integrated development between different energy sectors, such as electricity, heating, gas and transportation. This paper investigates the problem of optimal placement of a heat...... with the help of mathematical optimization that minimizes investments of both electric and heating utilities, achieving the reduction of the total investment. The optimization is performed in Matlab using built-in Genetic Algorithm function and Matpower software package for calculating power flow equations....

  3. Refrigerator Optimal Scheduling to Minimise the Cost of Operation

    Directory of Open Access Journals (Sweden)

    Bálint Roland

    2016-12-01

    Full Text Available The cost optimal scheduling of a household refrigerator is presented in this work. The fundamental approach is the model predictive control methodology applied to the piecewise affine model of the refrigerator.

  4. Optimization of fin geometry in heat convection with entransy theory

    Institute of Scientific and Technical Information of China (English)

    Cheng Xue-Tao; Zhang Qin-Zhao; Xu Xiang-Hua; Liang Xin-Gang

    2013-01-01

    The entransy theory developed in recent years is used to optimize the aspect ratio of a plate fin in heat convection.Based on a two-dimensional model,the theoretical analysis shows that the minimum thermal resistance defined with the concept of entransy dissipation corresponds to the maximum heat transfer rate when the temperature of the heating surface is fixed.On the other hand,when the heat flux of the heating surface is fixed,the minimum thermal resistance corresponds to the minimum average temperature of the heating surface.The entropy optimization is also given for the heat transfer processes.It is observed that the minimum entropy generation,the minimum entropy generation number,and the minimum revised entropy generation number do not always correspond to the best heat transfer performance.In addition,the influence factors on the optimized aspect ratio of the plate fin are also discussed.The optimized ratio decreases with the enhancement of heat convection,while it increases with fin thermal conductivity increasing.

  5. Horizontal ground coupled heat pump: Thermal-economic modeling and optimization

    Energy Technology Data Exchange (ETDEWEB)

    Sanaye, Sepehr; Niroomand, Behzad [Energy Systems Improvement Laboratory (ESIL), Department of Mechanical Engineering, Iran University of Science and Technology (IUST) (Iran)

    2010-12-15

    The modeling and optimizing processes of a Ground Coupled Heat Pump (GCHP) with closed Horizontal Ground Heat eXchanger (HGHX) are presented in this paper. After thermal modeling of GCHP including HGHX, the optimum design parameters of the system were estimated by minimizing a defined objective function (total of investment and operation costs) subject to a list of constraints. This procedure was performed applying Genetic Algorithm technique. For given heating/cooling loads and various climatic conditions, the optimum values of saturated temperature/pressure of condenser and evaporator as well as inlet and outlet temperatures of the water source in cooling and heating modes were predicted. Then, for our case study, the design parameters as well as the configuration of HGHX were obtained. Furthermore, the sensitivity analysis of change in the total annual cost of the system and optimum design parameters with the climatic conditions, cooling/heating capacity, and soil type were discussed. (author)

  6. Optimal heat rejection pressure in transcritical carbon dioxide air conditioning and heat pump systems

    DEFF Research Database (Denmark)

    Liao, Shengming; Jakobsen, Arne

    1998-01-01

    Due to the urgent need for environmentally benign refrigerants, the use of the natural substance carbon dioxide in refrigeration systems has gained more and more attention. In systems such as automobile air-conditioners and heat pumps, owing to the relatively high heat rejection temperatures......, the cycles using carbon dioxide as refrigerant will have to operate in the transcritical area. In a transcritical carbon dioxide system, there is an optimal heat rejection pressure that gives a maximum COP. In this paper, it is shown that the value of this optimal heat rejection pressure mainly depends...... dioxide air conditioning or heat pump systems and for intelligent controlling such systems....

  7. Optimal heat rejection pressure in transcritical carbon dioxide air conditioning and heat pump systems

    DEFF Research Database (Denmark)

    Liao, Shengming; Jakobsen, Arne

    1998-01-01

    Due to the urgent need for environmentally benign refrigerants, the use of the natural substance carbon dioxide in refrigeration systems has gained more and more attention. In systems such as automobile air-conditioners and heat pumps, owing to the relatively high heat rejection temperatures...... dioxide air conditioning or heat pump systems and for intelligent controlling such systems......., the cycles using carbon dioxide as refrigerant will have to operate in the transcritical area. In a transcritical carbon dioxide system, there is an optimal heat rejection pressure that gives a maximum COP. In this paper, it is shown that the value of this optimal heat rejection pressure mainly depends...

  8. Cost Optimization Through Open Source Software

    Directory of Open Access Journals (Sweden)

    Mark VonFange

    2010-12-01

    Full Text Available The cost of information technology (IT as a percentage of overall operating and capital expenditures is growing as companies modernize their operations and as IT becomes an increasingly indispensable part of company resources. The price tag associated with IT infrastructure is a heavy one, and, in today's economy, companies need to look for ways to reduce overhead while maintaining quality operations and staying current with technology. With its advancements in availability, usability, functionality, choice, and power, free/libre open source software (F/LOSS provides a cost-effective means for the modern enterprise to streamline its operations. iXsystems wanted to quantify the benefits associated with the use of open source software at their company headquarters. This article is the outgrowth of our internal analysis of using open source software instead of commercial software in all aspects of company operations.

  9. Optimal investment with fixed refinancing costs

    OpenAIRE

    Cummins, Jason G; Ingmar Nyman

    2001-01-01

    Case studies show that corporate managers seek financial independence to avoid interference by outside financiers. We incorporate this financial xenophobia as a fixed cost in a simple dynamic model of financing and investment. To avoid refinancing in the future, the firm alters its behavior depending on the extent of its financial xenophobia and the realization of a revenue shock. With a sufficiently adverse shock, the firm holds no liquidity. Otherwise, the firm precautionarily saves and hol...

  10. Optimal Covering Tours with Turn Costs

    OpenAIRE

    Arkin, Esther M.; Bender, Michael A.; Demaine, Erik D.; Fekete, Sandor P.; Mitchell, Joseph S.B.; Sethia, Saurabh

    2003-01-01

    We give the first algorithmic study of a class of ``covering tour'' problems related to the geometric Traveling Salesman Problem: Find a polygonal tour for a cutter so that it sweeps out a specified region (``pocket''), in order to minimize a cost that depends mainly on the number of em turns. These problems arise naturally in manufacturing applications of computational geometry to automatic tool path generation and automatic inspection systems, as well as arc routing (``postman'') problems w...

  11. Optimized ground coupled heat pump design: Phase 1, Final report

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, J.W.; Catan, M.; Le Doux, P.; Metz, P.D.; Saunders, J.H.

    1985-10-01

    This report describes the first phase of a project to design a water-to-air heat pump optimized for ground coupling applications. The project is being conducted jointly by Brookhaven National Laboratory (BNL), Oak Ridge National Laboratory (ORNL), and an industrial partner to be selected via a competitive procurement. In the completion of Phase I, three major tasks were completed. First, based on experimental work performed at BNL, water-refrigerant heat exchanger models were developed for incorporation into the ORNL heat pump optimization program. Next, a procedure was developed to generate correlations between heat pump entering fluid temperature and load. The correlations, called ''Source Temperature/Load Maps'', will tell the optimization program how many hours/season the heat pump will operate with any pair of values for these quantities. This report discusses these first two tasks within Phase I.

  12. Optimization of the Single Staggered Wire and Tube Heat Exchanger

    OpenAIRE

    Arsana I Made; Susianto; Budhikarjono Kusno; Altway Ali

    2016-01-01

    Wire and tube heat exchanger consists of a coiled tube, and wire is welded on the two sides of it in normal direction of the tube. Generally,wire and tube heat exchanger uses inline wire arrangement between the two sides, whereas in this study, it used staggered wire arrangement that reduces the restriction of convection heat transfer. This study performed the optimization of single staggered wire and tube heat exchanger to increase the capacity and reduce the mass of the heat exchanger. Opti...

  13. The optimization model of the heat conduction structure

    Institute of Scientific and Technical Information of China (English)

    Yongcun Zhang; Shutian Liu

    2008-01-01

    An optimization model considering a novel thermal performance index to be the objective function is proposed for minimizing the highest temperature in this paper. Firstly, the performance of the conventional heat conduction optimization model, with the dissipation of heat transport potential capacity as the objective function, is evaluated by a one-dimensional heat conduction problem in a planar plate exchanger. Then, a new thermal performance index, named the geometric average temperature, is introduced. The new heat conduction optimization model, with the geometric average temperature as the objective function, is developed and the corresponding finite element formula is presented. The results show that the geometric average temperature is an ideal thermal performance index and the solution of the new model is close to the theoretical optimal solution.

  14. Objective function of cost in optimal tolerance allocation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An objective function model is proposed for cost in optimizing and allocating tolerance with consideration of manufacturing conditions. With the fuzzy comprehensive evaluation method, a manufacturing difficulty coefficient is derived, which takes into account of several factors affecting the manufacturing cost, including the forming means of the blank, size, machining surface features, operator's skills and machinability of materials.The coefficient is then converted into a weight factor used in the inversed square model representing the relationship between the cost and tolerance, and, hence, an objective function for cost is established in optimizing and allocating tolerance. The higher is the manufacturing difficulty coefficient, the higher is the relative manufacturing cost and the higher is the weight factor of the tolerance allocation, which indicates the increase of the tolerance's effects on the total manufacturing cost and, therefore, a larger tolerance should be allocated. The computer-aided tolerance allocation utilizing this model makes it more convenient, accurate and practicable.

  15. District Heating Network Design and Configuration Optimization with Genetic Algorithm

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    2013-01-01

    and the pipe friction and heat loss formulations are non-linear. In order to find the optimal district heating network configuration, genetic algorithm which handles the mixed integer nonlinear programming problem is chosen. The network configuration is represented with binary and integer encoding...

  16. Optimal Shielding for Minimum Materials Cost of Mass

    Energy Technology Data Exchange (ETDEWEB)

    Woolley, Robert D. [PPPL

    2014-08-01

    Material costs dominate some shielding design problems. This is certainly the case for manned nuclear power space applications for which shielding is essential and the cost of launching by rocket from earth is high. In such situations or in those where shielding volume or mass is constrained, it is important to optimize the design. Although trial and error synthesis methods may succeed a more systematic approach is warranted. Design automation may also potentially reduce engineering costs.

  17. Cost-optimized climate stabilisation (OPTIKS)

    Energy Technology Data Exchange (ETDEWEB)

    Leimbach, Marian; Bauer, Nico; Baumstark, Lavinia; Edenhofer, Ottmar [Potsdam Institut fuer Klimafolgenforschung, Potsdam (Germany)

    2009-11-15

    This study analyses the implications of suggestions for the design of post-2012 climate policy regimes on the basis of model simulations. The focus of the analysis, the determination of regional mitigation costs and the technological development in the energy sector, also considers the feedbacks of investment and trade decisions of the regions that are linked by different global markets for emission permits, goods and resources. The analysed policy regimes are primarily differentiated by their allocation of emission rights. Moreover, they represent alternative designs of an international cap and trade system that is geared to meet the 2 C climate target. The present study analyses ambitious climate protection scenarios that require drastic reduction policies (reductions of 60%-80% globally until 2050). Immediate and multilateral action is needed in such scenarios. Given the rather small variance of mitigation costs in major regions like UCA, Europe, MEA and China, a policy regime should be chosen that provides high incentives to join an international agreement for the remaining regions. From this perspective either the C and C scenario (incentive for Russia) is preferable or the multi-stage approach (incentive for Africa and India). (orig.)

  18. Optimizing quality, service, and cost through innovation.

    Science.gov (United States)

    Walker, Kathleen; Allen, Jennifer; Andrews, Richard

    2011-01-01

    With dramatic increases in health care costs and growing concerns about the quality of health care services, nurse executives are seeking ways to transform their organizations to improve operational and financial performance while enhancing quality care and patient safety. Nurse leaders are challenged to meet new cost, quality and service imperatives, and change cannot be achieved by traditional approaches, it must occur through innovation. Imagine an organization that can mitigate a $56 million loss in revenue and claim the following successes: Increase admissions by a 8 day and a $5.5 million annualized increase by repurposing existing space. Decrease emergency department holding hours by an average of 174 hours a day, with a labor savings of $502,000 annually. Reduce overall inpatient length of stay by 0.5 day with total compensation running $4.2 million less than the budget for first quarter of 2010. Grow emergency department volume 272 visits greater than budgeted for first quarter of 2010. Complete admission assessments and diagnostics in 90 minutes. This article will address how these outcomes were achieved by transforming care delivery, creating a patient transition center, enhancing outreach referrals, and revising admission processes through collaboration and innovation.

  19. Implementing the cost-optimal methodology in EU countries

    DEFF Research Database (Denmark)

    Atanasiu, Bogdan; Kouloumpi, Ilektra; Thomsen, Kirsten Engelund

    . Therefore, this study provides more evidence on the implementation of the cost-optimal methodology and highlights the implications of choosing different values for key factors (e.g. discount rates, simulation variants/packages, costs, energy prices) at national levels. The study demonstrates how existing...... national nZEB definitions can be tested for cost-optimality and explores additional implications of the EU decarbonisation and resource efficiency goals. Thus, the study will ultimately contribute to prompt the transition towards the implementation of nZEB by 2020. Project coordination is the Buildings...

  20. Modeling and Optimization for Heat Exchanger Networks Synthesis Based on Expert System and Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    LIZhihong

    2002-01-01

    A new superstructure from of heat exchanger networks(HEN) is proposed based on expert system (ES). The new superstructure from is combined with the practical engineering.The different investment cost formula for different heat exchanger is also presented based on ES.The mathematical model for the simultaneous optimization of network configuration is established and solved by a genetic algorithm.This method can deal with larger scale HEN synthesis and the optimal HEN configuration is obtained automatically.Finally,a case study is presented to demonstrate the effectiveness of the method.

  1. Feedback Solution to Optimal Switching Problems With Switching Cost.

    Science.gov (United States)

    Heydari, Ali

    2016-10-01

    The problem of optimal switching between nonlinear autonomous subsystems is investigated in this paper where the objective is not only bringing the states to close to the desired point, but also adjusting the switching pattern, in the sense of penalizing switching occurrences and assigning different preferences to utilization of different modes. The mode sequence is unspecified and a switching cost term is used in the cost function for penalizing each switching. It is shown that once a switching cost is incorporated, the optimal cost-to-go function depends on the subsystem which was active at the previous time step. Afterward, an approximate dynamic programming-based method is developed, which provides an approximation of the optimal solution to the problem in a feedback form and for different initial conditions. Finally, the performance of the method is analyzed through numerical examples.

  2. Optimal Power Cost Management Using Stored Energy in Data Centers

    CERN Document Server

    Urgaonkar, Rahul; Neely, Michael J; Sivasubramaniam, Anand

    2011-01-01

    Since the electricity bill of a data center constitutes a significant portion of its overall operational costs, reducing this has become important. We investigate cost reduction opportunities that arise by the use of uninterrupted power supply (UPS) units as energy storage devices. This represents a deviation from the usual use of these devices as mere transitional fail-over mechanisms between utility and captive sources such as diesel generators. We consider the problem of opportunistically using these devices to reduce the time average electric utility bill in a data center. Using the technique of Lyapunov optimization, we develop an online control algorithm that can optimally exploit these devices to minimize the time average cost. This algorithm operates without any knowledge of the statistics of the workload or electricity cost processes, making it attractive in the presence of workload and pricing uncertainties. An interesting feature of our algorithm is that its deviation from optimality reduces as the...

  3. Optimal Work Effort and Monitoring Cost

    Directory of Open Access Journals (Sweden)

    Tamara Todorova

    2012-12-01

    Full Text Available Using a simple job market equilibrium model we study the relationship between work effort and monitoring by firms. Some other determinants of work effort investigated include the educational level of the worker, the minimum or start-up salary as well as the economic conjuncture. As common logic dictates, optimal work effort increases with the amount of monitoring done by the employer. Quite contrary to common logic, though, we find that at the optimum employers observe and control good workers much more stringently and meticulously than poor workers. This is because under profit maximization most of the employer’s profit and surplus result from good workers and he risks losing a large amount of profit by not observing those. Managers monitor strictly more productive workers, fast learners and those starting at a higher autonomous level of monitoring, as those contribute more substantially to the firm’s profit.

  4. Starship Sails Propelled by Cost-Optimized Directed Energy

    Science.gov (United States)

    Benford, J.

    Microwave and laser-propelled sails are a new class of spacecraft using photon acceleration. It is the only method of interstellar flight that has no physics issues. Laboratory demonstrations of basic features of beam-driven propulsion, flight, stability (`beam-riding'), and induced spin, have been completed in the last decade, primarily in the microwave. It offers much lower cost probes after a substantial investment in the launcher. Engineering issues are being addressed by other applications: fusion (microwave, millimeter and laser sources) and astronomy (large aperture antennas). There are many candidate sail materials: carbon nanotubes and microtrusses, beryllium, graphene, etc. For acceleration of a sail, what is the cost-optimum high power system? Here the cost is used to constrain design parameters to estimate system power, aperture and elements of capital and operating cost. From general relations for cost-optimal transmitter aperture and power, system cost scales with kinetic energy and inversely with sail diameter and frequency. So optimal sails will be larger, lower in mass and driven by higher frequency beams. Estimated costs include economies of scale. We present several starship point concepts. Systems based on microwave, millimeter wave and laser technologies are of equal cost at today's costs. The frequency advantage of lasers is cancelled by the high cost of both the laser and the radiating optic. Cost of interstellar sailships is very high, driven by current costs for radiation source, antennas and especially electrical power. The high speeds necessary for fast interstellar missions make the operating cost exceed the capital cost. Such sailcraft will not be flown until the cost of electrical power in space is reduced orders of magnitude below current levels.

  5. Optimizing cost-efficiency in mean exposure assessment - cost functions reconsidered

    Directory of Open Access Journals (Sweden)

    Bolin Kristian

    2011-05-01

    Full Text Available Abstract Background Reliable exposure data is a vital concern in medical epidemiology and intervention studies. The present study addresses the needs of the medical researcher to spend monetary resources devoted to exposure assessment with an optimal cost-efficiency, i.e. obtain the best possible statistical performance at a specified budget. A few previous studies have suggested mathematical optimization procedures based on very simple cost models; this study extends the methodology to cover even non-linear cost scenarios. Methods Statistical performance, i.e. efficiency, was assessed in terms of the precision of an exposure mean value, as determined in a hierarchical, nested measurement model with three stages. Total costs were assessed using a corresponding three-stage cost model, allowing costs at each stage to vary non-linearly with the number of measurements according to a power function. Using these models, procedures for identifying the optimally cost-efficient allocation of measurements under a constrained budget were developed, and applied on 225 scenarios combining different sizes of unit costs, cost function exponents, and exposure variance components. Results Explicit mathematical rules for identifying optimal allocation could be developed when cost functions were linear, while non-linear cost functions implied that parts of or the entire optimization procedure had to be carried out using numerical methods. For many of the 225 scenarios, the optimal strategy consisted in measuring on only one occasion from each of as many subjects as allowed by the budget. Significant deviations from this principle occurred if costs for recruiting subjects were large compared to costs for setting up measurement occasions, and, at the same time, the between-subjects to within-subject variance ratio was small. In these cases, non-linearities had a profound influence on the optimal allocation and on the eventual size of the exposure data set

  6. Solar Water Heating with Low-Cost Plastic Systems

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-01-01

    Federal buildings consumed over 392,000 billion Btu of site delivered energy for buildings during FY 2007 at a total cost of $6.5 billion. Earlier data indicate that about 10% of this is used to heat water.[2] Targeting energy consumption in Federal buildings, the Energy Independence and Security Act of 2007 (EISA) requires new Federal buildings and major renovations to meet 30% of their hot water demand with solar energy, provided it is cost-effective over the life of the system. In October 2009, President Obama expanded the energy reduction and performance requirements of EISA and its subsequent regulations with his Executive Order 13514.

  7. BASIMO - Borehole Heat Exchanger Array Simulation and Optimization Tool

    Science.gov (United States)

    Schulte, Daniel; Rühaak, Wolfram; Welsch, Bastian; Bär, Kristian; Sass, Ingo

    2016-04-01

    Borehole heat exchangers represent a well-established technology, which pushes for new fields of applications and novel modifications. Current simulation tools cannot - or only to some extent - describe features like inclined or partly insulated boreholes unless they run fully discretized models of the borehole heat exchangers. However, fully discretized models often come at a high computational cost, especially for large arrays of borehole heat exchangers. We present a tool, which uses one dimensional thermal resistance and capacity models for the borehole heat exchangers coupled with a numerical finite element model for the subsurface heat transport. An unstructured tetrahedral mesh bypasses the limitations of structured grids for borehole path geometries, while the thermal resistance and capacity model is improved to account for borehole heat exchanger properties changing with depth. The presented tool benefits from the fast analytical solution of the thermal interactions within the boreholes while still allowing for a detailed consideration of the borehole heat exchanger properties.

  8. Ecological optimization of an irreversible harmonic oscillators Carnot heat engine

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A model of an irreversible quantum Carnot heat engine with heat resistance,internal irreversibility and heat leakage and many non-interacting harmonic oscillators is established in this paper. Based on the quantum master equation and semi-group approach,equations of some important performance parameters,such as power output,efficiency,exergy loss rate and ecological function for the irreversible quantum Carnot heat engine are derived. The optimal ecological performance of the heat engine in the classical limit is analyzed with numerical examples. Effects of internal irreversibility and heat leakage on the ecological performance are discussed. A performance comparison of the quantum heat engine under maximum ecological function and maximum power conditions is also performed.

  9. Ecolosical optimization of an irreversible harmonic oscillators Carnot heat engine

    Institute of Scientific and Technical Information of China (English)

    LIU XiaoWei; CHEN LinGen; WU Feng; SUN FengRui

    2009-01-01

    A model of an irreversible quantum Carnot heat engine with heat resistance, internal irreversibility and heat leakage and many non-interacting harmonic oscillators is established in this paper. Based on the quantum master equation and semi-group approach, equations of some important performance parameters, such as power output, efficiency, exergy loss rate and ecological function for the irreversible quantum Carnot heat engine are derived. The optimal ecological performance of the heat engine in the classical limit is analyzed with numerical examples. Effects of internal irreversibility and heat leakage on the ecological performance are discussed. A performance comparison of the quantum heat engine under maximum ecological function and maximum power conditions is also performed.

  10. Finite time exergoeconomic performance optimization of a thermoacoustic heat engine

    Directory of Open Access Journals (Sweden)

    Xuxian Kan, Lingen Chen, Fengrui Sun, Feng Wu

    2011-01-01

    Full Text Available Finite time exergoeconomic performance optimization of a generalized irreversible thermoacoustic heat engine with heat resistance, heat leakage, thermal relaxation, and internal dissipation is investigated in this paper. Both the real part and the imaginary part of the complex heat transfer exponent change the optimal profit rate versus efficiency relationship quantitatively. The operation of the generalized irreversible thermoacoustic engine is viewed as a production process with exergy as its output. The finite time exergoeconomic performance optimization of the generalized irreversible thermoacoustic engine is performed by taking profit rate as the objective. The analytical formulas about the profit rate and thermal efficiency of the thermoacoustic engine are derived. Furthermore, the comparative analysis of the influences of various factors on the relationship between optimal profit rate and the thermal efficiency of the generalized irreversible thermoacoustic engine is carried out by detailed numerical examples. The optimal zone on the performance of the thermoacoustic heat engine is obtained by numerical analysis. The results obtained herein may be useful for the selection of the operation parameters for real thermoacoustic heat engines.

  11. Optimal power and efficiency of quantum Stirling heat engines

    Science.gov (United States)

    Yin, Yong; Chen, Lingen; Wu, Feng

    2017-01-01

    A quantum Stirling heat engine model is established in this paper in which imperfect regeneration and heat leakage are considered. A single particle which contained in a one-dimensional infinite potential well is studied, and the system consists of countless replicas. Each particle is confined in its own potential well, whose occupation probabilities can be expressed by the thermal equilibrium Gibbs distributions. Based on the Schrödinger equation, the expressions of power output and efficiency for the engine are obtained. Effects of imperfect regeneration and heat leakage on the optimal performance are discussed. The optimal performance region and the optimal values of important parameters of the engine cycle are obtained. The results obtained can provide some guidelines for the design of a quantum Stirling heat engine.

  12. Optimal Orthogonal Graph Drawing with Convex Bend Costs

    CERN Document Server

    Bläsius, Thomas; Wagner, Dorothea

    2012-01-01

    Traditionally, the quality of orthogonal planar drawings is quantified by either the total number of bends, or the maximum number of bends per edge. However, this neglects that in typical applications, edges have varying importance. Moreover, as bend minimization over all planar embeddings is NP-hard, most approaches focus on a fixed planar embedding. We consider the problem OptimalFlexDraw that is defined as follows. Given a planar graph G on n vertices with maximum degree 4 and for each edge e a cost function cost_e : N_0 --> R defining costs depending on the number of bends on e, compute an orthogonal drawing of G of minimum cost. Note that this optimizes over all planar embeddings of the input graphs, and the cost functions allow fine-grained control on the bends of edges. In this generality OptimalFlexDraw is NP-hard. We show that it can be solved efficiently if 1) the cost function of each edge is convex and 2) the first bend on each edge does not cause any cost (which is a condition similar to the posi...

  13. The cost of approximate controllability for semilinear heat equations

    Institute of Scientific and Technical Information of China (English)

    Yuqing YAN; Yi ZHAO; Yu HUANG

    2009-01-01

    We consider the semilinear heat equation with globally Lipschitz non-linearity involving gradient terms in a bounded domain of Rn.In this paper,we obtain explicit bounds of the cost of approximate controllability,i.e.,of the minimal norm of a control needed to control the system approximately.The methods we used combine global Carleman estimates,the variational approach to approximate controllability and Schauder's fixed point theorem.

  14. PSO Based Optimization of Testing and Maintenance Cost in NPPs

    Directory of Open Access Journals (Sweden)

    Qiang Chou

    2014-01-01

    Full Text Available Testing and maintenance activities of safety equipment have drawn much attention in Nuclear Power Plant (NPP to risk and cost control. The testing and maintenance activities are often implemented in compliance with the technical specification and maintenance requirements. Technical specification and maintenance-related parameters, that is, allowed outage time (AOT, maintenance period and duration, and so forth, in NPP are associated with controlling risk level and operating cost which need to be minimized. The above problems can be formulated by a constrained multiobjective optimization model, which is widely used in many other engineering problems. Particle swarm optimizations (PSOs have proved their capability to solve these kinds of problems. In this paper, we adopt PSO as an optimizer to optimize the multiobjective optimization problem by iteratively trying to improve a candidate solution with regard to a given measure of quality. Numerical results have demonstrated the efficiency of our proposed algorithm.

  15. Throughput Optimal Scheduling with Feedback Cost Reduction

    CERN Document Server

    Karaca, Mehmet; Ercetin, Ozgur; Alpcan, Tansu; Boche, Holger

    2012-01-01

    It is well known that opportunistic scheduling algorithms are throughput optimal under full knowledge of channel and network conditions. However, these algorithms achieve a hypothetical achievable rate region which does not take into account the overhead associated with channel probing and feedback required to obtain the full channel state information at every slot. We adopt a channel probing model where $\\beta$ fraction of time slot is consumed for acquiring the channel state information (CSI) of a single channel. In this work, we design a joint scheduling and channel probing algorithm named SDF by considering the overhead of obtaining the channel state information. We analytically prove that when the number of users in the network is greater than 3, then SDF algorithm can achieve $1+\\epsilon$ of the full rate region achieved when all users are probed. We also demonstrate numerically in a realistic simulation setting that this rate region can be achieved by probing only less than 50% of all channels in a CDM...

  16. A new optimization approach for shell and tube heat exchangers by using electromagnetism-like algorithm (EM)

    Science.gov (United States)

    Abed, Azher M.; Abed, Issa Ahmed; Majdi, Hasan Sh.; Al-Shamani, Ali Najah; Sopian, K.

    2016-12-01

    This study proposes a new procedure for optimal design of shell and tube heat exchangers. The electromagnetism-like algorithm is applied to save on heat exchanger capital cost and designing a compact, high performance heat exchanger with effective use of the allowable pressure drop (cost of the pump). An optimization algorithm is then utilized to determine the optimal values of both geometric design parameters and maximum allowable pressure drop by pursuing the minimization of a total cost function. A computer code is developed for the optimal shell and tube heat exchangers. Different test cases are solved to demonstrate the effectiveness and ability of the proposed algorithm. Results are also compared with those obtained by other approaches available in the literature. The comparisons indicate that a proposed design procedure can be successfully applied in the optimal design of shell and tube heat exchangers. In particular, in the examined cases a reduction of total costs up to 30, 29, and 56.15 % compared with the original design and up to 18, 5.5 and 7.4 % compared with other approaches for case study 1, 2 and 3 respectively, are observed. In this work, economic optimization resulting from the proposed design procedure are relevant especially when the size/volume is critical for high performance and compact unit, moderate volume and cost are needed.

  17. Optimization-based design of a heat flux concentrator

    Science.gov (United States)

    Peralta, Ignacio; Fachinotti, Víctor D.; Ciarbonetti, Ángel A.

    2017-01-01

    To gain control over the diffusive heat flux in a given domain, one needs to engineer a thermal metamaterial with a specific distribution of the generally anisotropic thermal conductivity throughout the domain. Until now, the appropriate conductivity distribution was usually determined using transformation thermodynamics. By this way, only a few particular cases of heat flux control in simple domains having simple boundary conditions were studied. Thermal metamaterials based on optimization algorithm provides superior properties compared to those using the previous methods. As a more general approach, we propose to define the heat control problem as an optimization problem where we minimize the error in guiding the heat flux in a given way, taking as design variables the parameters that define the variable microstructure of the metamaterial. In the present study we numerically demonstrate the ability to manipulate heat flux by designing a device to concentrate the thermal energy to its center without disturbing the temperature profile outside it. PMID:28084451

  18. Design optimization of a polygeneration plant producing power, heat, and lignocellulosic ethanol

    DEFF Research Database (Denmark)

    Lythcke-Jørgensen, Christoffer Ernst; Haglind, Fredrik

    2015-01-01

    A promising way to increase the energy efficiency and reduce costs of biofuel production is to integrate it with heat and power production in polygeneration plants. This study treats the retrofitting of a Danish combined heat and power plant by integrating lignocellulosic ethanol production based...... production capacity, ranging from 0.746 for 5 kg/s to 0.696 for 12 kg/s. This trend results from operating constraints that induce expensive operation patterns in periods of high district heating loads or shut-down periods for the combined heat and power plant. A sensitivity analysis indicates that the found...... on wheat straw with the aim of minimizing specific ethanol production cost. Previously developed and validated models of the facilities are applied in the attempt to solve the design optimization problem. Straw processing capacities in the range of 5–12 kg/s are considered, while plant operation...

  19. Fundamental optimal relation of a generalized irreversible Carnot heat pump with complex heat transfer law

    Indian Academy of Sciences (India)

    Jun Li; Lingen Chen; Fengrui Sun

    2010-02-01

    The fundamental optimal relation between heating load and coefficient of performance (COP) of a generalized irreversible Carnot heat pump is derived based on a new generalized heat transfer law, which includes the generalized convective heat transfer law and generalized radiative heat transfer law, $q \\varpropto ( T^{n})^{m}$. The generalized irreversible Carnot heat pump model incorporates several internal and external irreversibilities, such as heat resistance, bypass heat leakage, friction, turbulence and other undesirable irreversibility factors. The added irreversibilities besides heat resistance are characterized by a constant parameter and a constant coefficient. The effects of heat transfer laws and various loss terms are analysed. The heating load vs. COP characteristic of a generalized irreversible Carnot heat pump is a parabolic-like curve, which is consistent with the experimental result of thermoelectric heat pump. The obtained results include those obtained in many literatures and indicated that the analysis results of the generalized irreversible Carnot heat pump were more suitable for engineering practice than those of the endoreversible Carnot heat pump.

  20. Optimizing cost-efficiency in mean exposure assessment - cost functions reconsidered

    OpenAIRE

    Bolin Kristian; Mathiassen Svend Erik

    2011-01-01

    Abstract Background Reliable exposure data is a vital concern in medical epidemiology and intervention studies. The present study addresses the needs of the medical researcher to spend monetary resources devoted to exposure assessment with an optimal cost-efficiency, i.e. obtain the best possible statistical performance at a specified budget. A few previous studies have suggested mathematical optimization procedures based on very simple cost models; this study extends the methodology to cover...

  1. Cost Optimization Using Hybrid Evolutionary Algorithm in Cloud Computing

    Directory of Open Access Journals (Sweden)

    B. Kavitha

    2015-07-01

    Full Text Available The main aim of this research is to design the hybrid evolutionary algorithm for minimizing multiple problems of dynamic resource allocation in cloud computing. The resource allocation is one of the big problems in the distributed systems when the client wants to decrease the cost for the resource allocation for their task. In order to assign the resource for the task, the client must consider the monetary cost and computational cost. Allocation of resources by considering those two costs is difficult. To solve this problem in this study, we make the main task of client into many subtasks and we allocate resources for each subtask instead of selecting the single resource for the main task. The allocation of resources for the each subtask is completed through our proposed hybrid optimization algorithm. Here, we hybrid the Binary Particle Swarm Optimization (BPSO and Binary Cuckoo Search algorithm (BCSO by considering monetary cost and computational cost which helps to minimize the cost of the client. Finally, the experimentation is carried out and our proposed hybrid algorithm is compared with BPSO and BCSO algorithms. Also we proved the efficiency of our proposed hybrid optimization algorithm.

  2. Cost-optimized design approach for steam condensers

    Energy Technology Data Exchange (ETDEWEB)

    Kurma Rao, P.S.V.

    1982-08-23

    Examines methods of selecting cooling water quality for a steam surface condenser operating in a power plant or in a process. Equations and graphs for determining optimum terminal temperature difference and optimum cooling water velocity are presented. With large quantity with large terminal temperature difference, water cost will be more, but the annual fixed charges for maintenance will be smaller because the surface area is less due to the large terminal temperature difference. With high velocities giving high heat transfer rates with less surface area, initial costs are low, but pumping costs will be higher.

  3. Optimization of Heat Exchangers for Intercooled Recuperated Aero Engines

    Directory of Open Access Journals (Sweden)

    Dimitrios Misirlis

    2017-03-01

    Full Text Available In the framework of the European research project LEMCOTEC, a section was devoted to the further optimization of the recuperation system of the Intercooled Recuperated Aero engine (IRA engine concept, of MTU Aero Engines AG. This concept is based on an advanced thermodynamic cycle combining both intercooling and recuperation. The present work is focused only on the recuperation process. This is carried out through a system of heat exchangers mounted inside the hot-gas exhaust nozzle, providing fuel economy and reduced pollutant emissions. The optimization of the recuperation system was performed using computational fluid dynamics (CFD computations, experimental measurements and thermodynamic cycle analysis for a wide range of engine operating conditions. A customized numerical tool was developed based on an advanced porosity model approach. The heat exchangers were modeled as porous media of predefined heat transfer and pressure loss behaviour and could also incorporate major and critical heat exchanger design decisions in the CFD computations. The optimization resulted in two completely new innovative heat exchanger concepts, named as CORN (COnical Recuperative Nozzle and STARTREC (STraight AnnulaR Thermal RECuperator, which provided significant benefits in terms of fuel consumption, pollutants emission and weight reduction compared to more conventional heat exchanger designs, thus proving that further optimization potential for this technology exists.

  4. Starship Sails Propelled by Cost-Optimized Directed Energy

    CERN Document Server

    Benford, James

    2011-01-01

    Microwave propelled sails are a new class of spacecraft using photon acceleration. It is the only method of interstellar flight that has no physics issues. Laboratory demonstrations of basic features of beam-driven propulsion, flight, stability ('beam-riding'), and induced spin, have been completed in the last decade, primarily in the microwave. It offers much lower cost probes after a substantial investment in the launcher. Engineering issues are being addressed by other applications: fusion (microwave, millimeter and laser sources) and astronomy (large aperture antennas). There are many candidate sail materials: carbon nanotubes and microtrusses, graphene, beryllium, etc. For acceleration of a sail, what is the cost-optimum high power system? Here the cost is used to constrain design parameters to estimate system power, aperture and elements of capital and operating cost. From general relations for cost-optimal transmitter aperture and power, system cost scales with kinetic energy and inversely with sail di...

  5. Life Cycle Cost Optimization of a BOLIG+ Zero Energy Building

    DEFF Research Database (Denmark)

    Marszal, Anna Joanna

    included in the current building code, and ten renewable energy supply systems including both on-site and off-site options. The results indicated that although the off-site options have lower life cycle costs than the on-site alternatives, their application would promote renewable technologies over energy......, cost-optimal “zero” energy balance accounts only for the building related energy use....... building owners’ approach to it. For this particular target group, the cost is often an obstacle when investing money in environmental or climate friendly products. Therefore, this PhD project took the perspective of a future private ZEB owner to investigate the cost-optimal Net ZEB definition applicable...

  6. Investigations of a Cost-Optimal Zero Energy Balance

    DEFF Research Database (Denmark)

    Marszal, Anna Joanna; Nørgaard, Jesper; Heiselberg, Per

    2012-01-01

    have indicated that with current energy prices and technology, a cost-optimal Net ZEB zero energy balance accounts for only the building related energy use. Moreover, with high user related energy use is even more in favour of excluding appliances from the zero energy balance......., in particular the types of energy use that should be included in it. Since the user perspective and the cost of energy-efficiency technologies is so crucial for the successful adaptation of energy-conservation solutions, such like the Net ZEB concept, this paper has deployed the Life Cycle Cost (LCC) analysis...... and taken a view point of private building owner to investigate what types of energy uses should be included in the cost-optimal zero energy balance. The analysis is conducted for five renewable energy supply systems and five user profiles with a study case of a multi-storey residential Net ZEB. The results...

  7. Increase Productivity and Cost Optimization in CNC Manufacturing

    Science.gov (United States)

    Musca, Gavril; Mihalache, Andrei; Tabacaru, Lucian

    2016-11-01

    The advantage of the technological assisted design consists in easy modification of the machining technologies for obtaining machine alternation, tool changing, working parameters variation or the modification of loads to which the tools are subjected. By determining tool movement inside machining and by using tool related moving speeds needed for both positioning and manufacturing we are able to compute the required machining time for each component of the machining operation in progress. The present study describes a cost optimization model for machining operations which uses the following components: machine and its operator related cost, set-up and adjustment, unproductive costs (idle state), direct and indirect costs. By using manufacturing technologies assisted design procedures we may obtain various variants for the technological model by modifying the machining strategy, tooling, working regimes or the machine-tool that are used. Simulating those variants allows us to compare and establish the optimal manufacturing variant as well as the most productive one.

  8. A new method to optimize natural convection heat sinks

    Science.gov (United States)

    Lampio, K.; Karvinen, R.

    2017-08-01

    The performance of a heat sink cooled by natural convection is strongly affected by its geometry, because buoyancy creates flow. Our model utilizes analytical results of forced flow and convection, and only conduction in a solid, i.e., the base plate and fins, is solved numerically. Sufficient accuracy for calculating maximum temperatures in practical applications is proved by comparing the results of our model with some simple analytical and computational fluid dynamics (CFD) solutions. An essential advantage of our model is that it cuts down on calculation CPU time by many orders of magnitude compared with CFD. The shorter calculation time makes our model well suited for multi-objective optimization, which is the best choice for improving heat sink geometry, because many geometrical parameters with opposite effects influence the thermal behavior. In multi-objective optimization, optimal locations of components and optimal dimensions of the fin array can be found by simultaneously minimizing the heat sink maximum temperature, size, and mass. This paper presents the principles of the particle swarm optimization (PSO) algorithm and applies it as a basis for optimizing existing heat sinks.

  9. Pareto Optimal Insurance Policies in the Presence of Administrative Costs

    OpenAIRE

    Aase, Knut K.

    2010-01-01

    In his classical article in The American Economic Review, Arthur Raviv (1979) examines Pareto optimal insurance contracts when there are ex-post insurance costs c induced by the indemnity I for loss x. Raviv’s main result is that a necessary and sufficient condition for the Pareto optimal deductible to be equal to zero is c0(I) = 0 for all I > 0(or I=0). We claim that another type of cost function is called for in household insurance, caused by frequent but relatively small ...

  10. Optimal Road Capacity Building : Road Planning by Marginal Cost Pricing

    OpenAIRE

    NEMOTO, Toshinori; Misui, Yuki; Kajiwara, Akira

    2009-01-01

    The purpose of this study is to propose a new road planning and financing scheme based on short-term social marginal cost pricing that facilitates the establishment of optimal road standards in the long term. We conducted a simulation analysis based on the proposed planning scheme and observed that the simulation calculated the optimal road capacity in the future, and thus proved that the new planning scheme is feasible.

  11. Thermal-economic multi-objective optimization of plate fin heat exchanger using genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Sanaye, Sepehr; Hajabdollahi, Hassan [Energy Systems Improvement Laboratory (ESIL), Department of Mechanical Engineering, Iran University of Science and Technology (IUST) (Iran)

    2010-06-15

    Thermal modeling and optimal design of compact heat exchangers are presented in this paper. {epsilon}NTU method was applied to estimate the heat exchanger pressure drop and effectiveness. Fin pitch, fin height, fin offset length, cold stream flow length, no-flow length and hot stream flow length were considered as six design parameters. Fast and elitist non-dominated sorting genetic-algorithm (NSGA-II) was applied to obtain the maximum effectiveness and the minimum total annual cost (sum of investment and operation costs) as two objective functions. The results of optimal designs were a set of multiple optimum solutions, called 'Pareto optimal solutions'. The sensitivity analysis of change in optimum effectiveness and total annual cost with change in design parameters of the plate fin heat exchanger was also performed and the results are reported. As a short cut for choosing the system optimal design parameters the correlations between two objectives and six decision variables with acceptable precision were presented using artificial neural network analysis. (author)

  12. Optimization of micro combined heat and power gas turbine by genetic algorithm

    Directory of Open Access Journals (Sweden)

    Yazdi Behnam Ahrar

    2015-01-01

    Full Text Available In this paper, a comprehensive thermodynamic modeling and multi-objective optimization of a micro turbine cycle in combined heat and power generation, which provides 100KW of electric power. This CHP System is composed of air compressor, combustion chamber (CC, Air Preheater, Gas Turbine (GT and a Heat Recovery Heat Exchanger. In this paper, at the first stage, the each part of the micro turbine cycle is modeled using thermodynamic laws. Next, with using the energetic and exergetic concepts and applying economic and environmental functions, the multi-objectives optimization of micro turbine in combined heat and power generation is performed. The design parameters of this cycle are compressor pressure ratio (rAC, compressor isentropic efficiency (ηAC, GT isentropic efficiency (ηGT, CC inlet temperature (T3, and turbine inlet temperature (T4. In the multi-objective optimization three objective functions, including CHP exergy efficiency, total cost rate of the system products, and CO2 emission of the whole plant, are considered. Theexergoenvironmental objective function is minimized whereas power plant exergy efficiency is maximized usinga Genetic algorithm. To have a good insight into this study, a sensitivity analysis of the result to the fuel cost is performed. The results show that at the lower exergetic efficiency, in which the weight of exergo-environmental objective is higher, the sensitivity of the optimal solutions to the fuel cost is much higher than the location of the Pareto Frontier with the lower weight of exergo-environmental objective. In addition, with increasing exergy efficiency, the purchase cost of equipment in the plant is increased as the cost rate of the plant increases.

  13. Optimizing Ice Thermal Storage to Reduce Energy Cost

    Science.gov (United States)

    Hall, Christopher L.

    Energy cost for buildings is an issue of concern for owners across the U.S. The bigger the building, the greater the concern. A part of this is due to the energy required to cool the building and the way in which charges are set when paying for energy consumed during different times of the day. This study will prove that designing ice thermal storage properly will minimize energy cost in buildings. The effectiveness of ice thermal storage as a means to reduce energy costs lies within transferring the time of most energy consumption from on-peak to off-peak periods. Multiple variables go into the equation of finding the optimal use of ice thermal storage and they are all judged with the final objective of minimizing monthly energy costs. This research discusses the optimal design of ice thermal storage and its impact on energy consumption, energy demand, and the total energy cost. A tool for optimal design of ice thermal storage is developed, considering variables such as chiller and ice storage sizes and charging and discharge times. The simulations take place in a four-story building and investigate the potential of Ice Thermal Storage as a resource in reducing and minimizing energy cost for cooling. The simulations test the effectiveness of Ice Thermal Storage implemented into the four-story building in ten locations across the United States.

  14. Production Cost Optimization Model Based on CODP in Mass Customization

    Directory of Open Access Journals (Sweden)

    Yanhong Qin

    2013-01-01

    Full Text Available The key for enterprises to implement the postponement strategy is the right decision on the location of Customer Order Decoupling Point (CODP so as to achieve the scope economics of mass customization and scale economics of mass production fully. To deal with production cost optimization problem of postponement system based on various situation of CODP, a basic model of production cost and its M/M/1 extended model are proposed and compared so as to optimize the overall production cost of the postponement system. The production modes can be classified as MTS (make to stock, ATO (assemble to order, MTO (make to order and ETO (engineering to order according to the inventory location, and the postponed production system considered here includes manufacturing cost, semi-finished inventory cost and customer waiting cost caused by delaying delivery. By Matlab simulation, we can compute the optimal location of CODP in each production mode, which can provide some management insight for the manufacturer to decide the right production mode and utilize the resources efficiently.

  15. Development of optimization method for plate heat exchanger with undulation

    Directory of Open Access Journals (Sweden)

    Dvořák Václav

    2016-01-01

    Full Text Available The article deals with optimization of undulated heat transfer surface of plate heat exchanger. The goal of optimization is not only to increase effectiveness of heat transfer but also to reduce the pressure drop. A combined pattern of undulation which combines herringbone pattern and wavy pattern was optimized and best values of four parameters were found; angle of herringbone pattern, number, phase and amplitude of longitudinal waves of wavy pattern. The optimization procedure looked for maximum of objective function which was a linear combination of effectiveness and pressure drop. We used simple Monte Carlo method and the optimum was searched for four values of reference pressure drop. Four different optimization were run and we investigated the effect of various definition of objective function and parameters of undulation. It was found that during optimization of combined pattern, the herringbone pattern is more favoured than wavy pattern. It is caused by the fact that herringbone pattern was described by the only one free parameter, which was the angle of undulation, and therefore it is more likely to be found by a stochastic method. This assumption was confirmed when simple wavy pattern was optimized and higher values of objective function and effectiveness were found.

  16. METHOD OF CALCULATING THE OPTIMAL HEAT EMISSION GEOTHERMAL WELLS

    Directory of Open Access Journals (Sweden)

    A. I. Akaev

    2015-01-01

    Full Text Available This paper presents a simplified method of calculating the optimal regimes of the fountain and the pumping exploitation of geothermal wells, reducing scaling and corrosion during operation. Comparative characteristics to quantify the heat of formation for these methods of operation under the same pressure at the wellhead. The problem is solved graphic-analytical method based on a balance of pressure in the well with the heat pump. 

  17. An Alternative Algorithm for Optimal Design of Plate Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Seyyed Morteza Javid

    2015-02-01

    Full Text Available Due to the complex geometry of plate heat exchangers and thus a large number of variables affecting the performance of the exchangers, the design of these types of exchangers is quiet difficult. However, unlike the shell and tube heat exchangers which contain available data of design procedures, the design of plate heat exchanger is a monopoly of some certain manufacturing companies that make the problem even worse. In this paper, the objective is to minimize the number of plates in plate heat exchanger; in order to achieve that, a simple and yet efficient mathematical model is introduced for determination of the pressure drop and heat capacity of a plate heat exchanger in single- and multipass state and also a program was defined for determination of optimal solution based on this simple mathematical model for given operational constraints and plate type. In the end, the optimal solution will be compared to the answer of CAS200 commercial software and also it is shown that the effect of the start and end plates and transverse distribution in optimal solution is considerable.

  18. Parametric Optimization of Thermoelectric Generators for Waste Heat Recovery

    Science.gov (United States)

    Huang, Shouyuan; Xu, Xianfan

    2016-10-01

    This paper presents a methodology for design optimization of thermoelectric-based waste heat recovery systems called thermoelectric generators (TEGs). The aim is to maximize the power output from thermoelectrics which are used as add-on modules to an existing gas-phase heat exchanger, without negative impacts, e.g., maintaining a minimum heat dissipation rate from the hot side. A numerical model is proposed for TEG coupled heat transfer and electrical power output. This finite-volume-based model simulates different types of heat exchangers, i.e., counter-flow and cross-flow, for TEGs. Multiple-filled skutterudites and bismuth-telluride-based thermoelectric modules (TEMs) are applied, respectively, in higher and lower temperature regions. The response surface methodology is implemented to determine the optimized TEG size along and across the flow direction and the height of thermoelectric couple legs, and to analyze their covariance and relative sensitivity. A genetic algorithm is employed to verify the globality of the optimum. The presented method will be generally useful for optimizing heat-exchanger-based TEG performance.

  19. Exergy optimization in a steady moving bed heat exchanger.

    Science.gov (United States)

    Soria-Verdugo, A; Almendros-Ibáñez, J A; Ruiz-Rivas, U; Santana, D

    2009-04-01

    This work provides an energy and exergy optimization analysis of a moving bed heat exchanger (MBHE). The exchanger is studied as a cross-flow heat exchanger where one of the phases is a moving granular medium. The optimal MBHE dimensions and the optimal particle diameter are obtained for a range of incoming fluid flow rates. The analyses are carried out over operation data of the exchanger obtained in two ways: a numerical simulation of the steady-state problem and an analytical solution of the simplified equations, neglecting the conduction terms. The numerical simulation considers, for the solid, the convection heat transfer to the fluid and the diffusion term in both directions, and for the fluid only the convection heat transfer to the solid. The results are compared with a well-known analytical solution (neglecting conduction effects) for the temperature distribution in the exchanger. Next, the analytical solution is used to derive an expression for the exergy destruction. The optimal length of the MBHE depends mainly on the flow rate and does not depend on particle diameter unless they become very small (thus increasing sharply the pressure drop). The exergy optimal length is always smaller than the thermal one, although the difference is itself small.

  20. The Application of Maximum Principle in Supply Chain Cost Optimization

    Directory of Open Access Journals (Sweden)

    Zhou Ling

    2013-09-01

    Full Text Available In this paper, using the maximum principle for analyzing dynamic cost, we propose a new two-stage supply chain model of the manufacturing-assembly mode for high-tech perishable products supply chain and obtain the optimal conditions and results. On this basis, we further research the effect of localization of CODP on the total cost and the relation of CODP, inventory policy and demand type through the data simulation. The results of simulation show that CODP locates in the downstream of the product life cycle, is a linear function of the product life cycle. The result indicates that the demand forecast is the main factors influencing the total cost; meanwhile the mode of production according to the demand forecast is the deciding factor of the total cost. Also the model can reflect the relation between the total cost of two-stage supply chain and inventory, demand.

  1. A cost optimization model for 100% renewable residential energy supply systems

    DEFF Research Database (Denmark)

    Milan, Christian; Bojesen, Carsten; Nielsen, Mads Pagh

    2012-01-01

    for the interdependencies between the different supply technologies as well as the construction energy of the installations, consumption profiles and on-site energy resource availability. This paper aims at developing such a model for the optimal sizing of renewable energy supply systems (RES) for residential Net ZEB......'s involving on-site production of heat and electricity in combination with electricity exchanged with the public grid. The model is based on linear programming and determines the optimal capacities for each relevant supply technology in terms of the overall system costs. It has been successfully applied...

  2. THE ATTAINABILITY OF THE PORTFOLIO OPTIMIZATION UNDER TRANSACTION COSTS

    Institute of Scientific and Technical Information of China (English)

    XU Shimeng; ZHANG Yuzhong

    2000-01-01

    We propose the concepts of normalized market and average hedging strategies, and discuss the attainability of the portfolio optimization under transaction costs and multiple stocks, by the extended forms of the martingale approach and the duality methods. Incidentally, we give an upper bound of the expectation of the portfolio at terminal investing time.

  3. Cost optimal river dike design using probabilistic methods

    NARCIS (Netherlands)

    Bischiniotis, K.; Kanning, W.; Jonkman, S.N.

    2014-01-01

    This research focuses on the optimization of river dikes using probabilistic methods. Its aim is to develop a generic method that automatically estimates the failure probabilities of many river dike cross-sections and gives the one with the least cost, taking into account the boundary conditions and

  4. Cost optimal river dike design using probabilistic methods

    NARCIS (Netherlands)

    Bischiniotis, K.; Kanning, W.; Jonkman, S.N.

    2014-01-01

    This research focuses on the optimization of river dikes using probabilistic methods. Its aim is to develop a generic method that automatically estimates the failure probabilities of many river dike cross-sections and gives the one with the least cost, taking into account the boundary conditions and

  5. Adjoint analyses of enhanced solidification for shape optimization in conjugate heat transfer problem

    Science.gov (United States)

    Morimoto, Kenichi; Kinoshita, Hidenori; Suzuki, Yuji

    2016-11-01

    In the present study, an adjoint-based shape-optimization method has been developed for designing extended heat transfer surfaces in conjugate heat transfer problems. Here we specifically consider heat conduction-dominated solidification problem under different thermal boundary conditions: (i) the isothermal condition, and (ii) the conjugate condition with thermal coupling between the solidified liquid and the solid wall inside the domain bounded by the extended heat transfer surface. In the present shape-optimization scheme, extended heat transfer surfaces are successively refined in a local way based on the variational information of a cost functional with respect to the shape modification. In the computation of the developed scheme, a meshless method is employed for dealing with the complex boundary shape. For high-resolution analyses with boundary-fitted node arrangement, we have introduced a bubble-mesh method combined with a high-efficiency algorithm for searching neighboring bubbles within a cut-off distance. The present technique can be easily applied to convection problems including high Reynolds number flow. We demonstrate, for the isothermal boundary condition, that the present optimization leads to tree-like fin shapes, which achieve the temperature field with global similarity for different initial fin shapes. We will also show the computational results for the conjugate condition, which would regularize the present optimization due to the fin-efficiency effect.

  6. Cost-Optimal Structural Reliability of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Tarp-Johansen, N. J.

    2004-01-01

    Wind turbines for electricity production are increasing drastically these years both in production capability and in size. Offshore wind turbines with an electricity production more than 5 MW are now being produced. The main failure modes are fatigue failure of wings, hub, shaft and main tower......, and failure costs. Different reconstruction policies in case of failure are considered, including systematic reconstruction in case of failure, no reconstruction and inspection and maintenance strategies. Illustrative examples for offshore wind turbines are presented, and as a part of the results optimal......, local buckling of main tower, and failure of the foundation. This paper considers reliability-based optimization of the tower and foundation. Different formulations are considered of the objective function including benefits, building costs of the wind turbine, inspection and maintenance costs...

  7. Cost-Optimal Structural Reliability of Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Tarp-Johansen, N. J.

    2004-01-01

    Wind turbines for electricity production are increasing drastically these years both in production capability and in size. Offshore wind turbines with an electricity production more than 5 MW are now being produced. The main failure modes are fatigue failure of wings, hub, shaft and main tower......, local buckling of main tower, and failure of the foundation. This paper considers reliability-based optimization of the tower and foundation. Different formulations are considered of the objective function including benefits, building costs of the wind turbine, inspection and maintenance costs......, and failure costs. Different reconstruction policies in case of failure are considered, including systematic reconstruction in case of failure, no reconstruction and inspection and maintenance strategies. Illustrative examples for offshore wind turbines are presented, and as a part of the results optimal...

  8. Optimized low-cost-array field designs for photovoltaic systems

    Energy Technology Data Exchange (ETDEWEB)

    Post, H.N.; Carmichael, D.C.; Castle, J.A.

    1982-01-01

    As manager of the US Department of Energy Photovoltaic Systems Definition Project, Sandia National Laboratories is engaged in a comprehensive program to define and develop array field subsystems which can achieve the lowest possible lifecycle costs. The major activity of this program is described, namely, the design and development of optimized, modular array fields for photovoltaic (PV) systems. As part of this activity, design criteria and performance requirements for specific array subsystems including support structures, foundations, intermodule connections, field wiring, lightning protection, system grounding, site preparation, and monitoring and control have been defined and evaluated. Similarly, fully integrated flat-panel array field designs, optimized for lowest lifecycle costs, have been developed for system sizes ranging from 20 to 500 kW/sub p/. Key features, subsystem requirements, and projected costs for these array field designs are presented and discussed.

  9. A simple quasi-dynamic model of a district heating system used for operational optimization

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Benny

    1998-12-01

    Equivalent models of DH (District Heating) systems are being developed and verified. The models will be used for operational optimization of DH systems. By nature this requires transient models of the DH network, however, some insight can be gained even from a steady state model of the DH network demonstrating the importance of the many parameters which are needed in the models. The temperature level as well as the line heat demand is low in Danish DH systems compared to many foreign DH systems. It has been advocated that the supply temperature should always be kept as low as possible in order to minimize the operational costs. However, this is not true in all cases as the optimum operational strategy will minimize the sum of the heat loss cost and the pumping cost. Thus in case of high line heat demands the supply temperature should not always be kept as low as possible. It has been shown that a simple model, i.e. one pipe - one bypass - one house, can be used for operational optimization, both in the steady state and in the transient case. What remains to be shown is how well this simple model can represent a whole district heating system. The optimization was carried out with matlab routines and with the high number of simulations performed, the computing time is rather long. Even, though much work has already been done, it is still not perfectly clear which demands must be put on simulation and optimization time steps in order to achieve a reliable solution without too much computational effort. (LN)

  10. Design optimization for cost and quality: The robust design approach

    Science.gov (United States)

    Unal, Resit

    1990-01-01

    Designing reliable, low cost, and operable space systems has become the key to future space operations. Designing high quality space systems at low cost is an economic and technological challenge to the designer. A systematic and efficient way to meet this challenge is a new method of design optimization for performance, quality, and cost, called Robust Design. Robust Design is an approach for design optimization. It consists of: making system performance insensitive to material and subsystem variation, thus allowing the use of less costly materials and components; making designs less sensitive to the variations in the operating environment, thus improving reliability and reducing operating costs; and using a new structured development process so that engineering time is used most productively. The objective in Robust Design is to select the best combination of controllable design parameters so that the system is most robust to uncontrollable noise factors. The robust design methodology uses a mathematical tool called an orthogonal array, from design of experiments theory, to study a large number of decision variables with a significantly small number of experiments. Robust design also uses a statistical measure of performance, called a signal-to-noise ratio, from electrical control theory, to evaluate the level of performance and the effect of noise factors. The purpose is to investigate the Robust Design methodology for improving quality and cost, demonstrate its application by the use of an example, and suggest its use as an integral part of space system design process.

  11. A Model for Optimization and Analysis of Energy Flexible Boiler Plants for Building Heating Purposes

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, J.R.

    1996-05-01

    This doctoral thesis presents a model for optimization and analysis of boiler plants. The model optimizes a boiler plant with respect to the annual total costs or with respect to energy consumption. The optimum solution is identified for a given number of energy carriers and defined characteristics of the heat production units. The number of heat production units and the capacity of units related to each energy carrier or the capacity of units related to the same energy carrier can be found. For a problem comprising large variation during a defined analysis period the model gives the operating costs and energy consumption to be used in an extended optimization. The model can be used to analyse the consequences with respect to costs and energy consumption due to capacity margins and shifts in the boundary conditions. The model is based on a search approach comprising an operational simulator. The simulator is based on a marginal cost method and dynamic programming. The simulation is performed on an hourly basis. A general boiler characteristic representation is maintained by linear energy or cost functions. The heat pump characteristics are represented by tabulated performance and efficiency as function of state and nominal aggregate capacities. The simulation procedure requires a heat load profile on an hourly basis. The problem of the presence of capacity margins in boiler plants is studied for selected cases. The single-boiler, oil-fired plant is very sensitive to the magnitude of the losses present during burner off-time. For a plant comprising two oil-fired burners, the impact of a capacity margin can be dampened by the selected capacity configuration. The present incentive, in Norway, to install an electric element boiler in an oil-fired boiler plant is analysed. 77 refs., 74 figs., 12 tabs.

  12. Shape Optimization of Inclined Ribs as Heat Transfer Augmentation Device

    Institute of Scientific and Technical Information of China (English)

    Kwang-Yong Kim; Hong-Min Kim

    2006-01-01

    This work presents numerical optimization techniques for the design of a rectangular channel with inclined ribs to enhance turbulent heat transfer.The response surface method with Reynolds-averaged Navier-Stokes analysis is used for optimization.Shear stress transport turbulence model is used as a turbulence closure.Computational results for local heat transfer rate show a reasonable agreement with the experimental data.Width-to-rib height ratio and attack angle of the rib are chosen as design variables.The objective function is defined as a linear combination of heat-transfer and friction-loss related terms with the weighting factor.Full-factorial experimental design method is used to determine the data points.Optimum shapes of the channel have been obtained in a range of the weighting factor.

  13. Optimal Cost-Analysis and Design of Circular Footings

    Directory of Open Access Journals (Sweden)

    Prabir K. Basudhar

    2012-10-01

    Full Text Available The study pertains to the optimal cost-analysis and design of a circular footing subjected to generalized loadings using sequential unconstrained minimization technique (SUMT in conjunction with Powell’s conjugate direction method for multidimensional search and quadratic interpolation method for one dimensional minimization. The cost of the footing is minimized satisfying all the structural and geotechnical engineering design considerations. As extended penalty function method has been used to convert the constrained problem into an unconstrained one, the developed technique is capable of handling both feasible and infeasible initial design vector. The net saving in cost starting from the best possible manual design ranges from 10 to 20 %. For all practical purposes, the optimum cost is independent of the initial design point. It was observed that for better convergence, the transition parameter  should be chosen at least 100 times the initial penalty parameter kr .

  14. Cost-Optimal Operation of Energy Storage Units: Benefits of a Problem-Specific Approach

    CERN Document Server

    Siemer, Lars; Kleinhans, David

    2015-01-01

    The integration of large shares of electricity produced by non-dispatchable Renewable Energy Sources (RES) leads to an increasingly volatile energy generation side, with temporary local overproduction. The application of energy storage units has the potential to use this excess electricity from RES efficiently and to prevent curtailment. The objective of this work is to calculate cost-optimal charging strategies for energy storage units used as buffers. For this purpose, a new mathematical optimization method is presented that is applicable to general storage-related problems. Due to a tremendous gain in efficiency of this method compared with standard solvers and proven optimality, calculations of complex problems as well as a high-resolution sensitivity analysis of multiple system combinations are feasible within a very short time. As an example technology, Power-to-Heat converters used in combination with thermal storage units are investigated in detail and optimal system configurations, including storage ...

  15. Optimal Heat Transport in Rayleigh-B\\'enard Convection

    CERN Document Server

    Sondak, David; Waleffe, Fabian

    2015-01-01

    Steady flows that optimize heat transport are obtained for two-dimensional Rayleigh-B\\'enard convection with no-slip horizontal walls for a variety of Prandtl numbers $Pr$ and Rayleigh number up to $Ra\\sim 10^9$. Power law scalings of $Nu\\sim Ra^{\\gamma}$ are observed with $\\gamma\\approx 0.31$, where the Nusselt number $Nu$ is a non-dimensional measure of the vertical heat transport. Any dependence of the scaling exponent on $Pr$ is found to be extremely weak. On the other hand, the presence of two local maxima of $Nu$ with different horizontal wavenumbers at the same $Ra$ leads to the emergence of two different flow structures as candidates for optimizing the heat transport. For $Pr \\lesssim 7$, optimal transport is achieved at the smaller maximal wavenumber. In these fluids, the optimal structure is a plume of warm rising fluid which spawns left/right horizontal arms near the top of the channel, leading to downdrafts adjacent to the central updraft. For $Pr > 7$ at high-enough Ra, the optimal structure is a...

  16. APECS: A family of optimization products for least cost generation

    Energy Technology Data Exchange (ETDEWEB)

    Petrill, E.; Stallings, J. [Electric Power Research Institute, Palo Alto, CA (United States); Shea, S. [Praxis Engineering, Inc., Milpitas, CA (United States)

    1996-05-01

    Reducing costs of power generation is the primary focus of many power generators today in efforts to prepare for competition in a deregulated market, to increase profitability, or to retain customers. To help power generators track and manage power generation costs, the Electric Power Research Institute (EPRI) offers APECS{sup plus}, one of EPRI`s APECS - Advisory Plant and Environmental Control System - family of optimization products for fossil power plants. The APECS family of products provides tools and techniques to optimize costs, as well as NO{sub x} emissions and performance, in fossil power plants. These products include APECS{sup plus}, GNOCIS, and ULTRAMAX{reg_sign}. The products have varying degrees of functionality and their application at a power plant will depend on the site-specific needs and resources in each case. This paper describes APECS{sup plus}, the cost management product of the APECS family of optimization products. The other key products in this family, GNOCIS and ULTRAMAX{reg_sign}, are mentioned here and described in more detail in the literature.

  17. Biologically Inspired Optimization of Building District Heating Networks

    Directory of Open Access Journals (Sweden)

    Leiming Shang

    2013-07-01

    Full Text Available In this paper we show that a biologically inspired model can be successfully applied to problems of building optimal district heating network. The model is based on physiological observations of the true slime mold Physarumpolycephalum, but can also be used for path-finding in the complicated networks of mazes and road maps. A strategy of optimally building heating distribution network was guided by the model and a well-tuned ant colony algorithm and genetic algorithm. The results indicate that although there are not large-scale efficiency savings to be made, the biologically inspired amoeboid movement model is capable of finding results of equal or better optimality than a comparable ant colony algorithm and genetic algorithm.

  18. A coordinated dispatch model for electricity and heat in a Microgrid via particle swarm optimization

    DEFF Research Database (Denmark)

    Xu, Lizhong; Yang, Guangya; Xu, Zhao

    2013-01-01

    This paper develops a coordinated electricity and heat dispatching model for Microgrid under day-ahead environment. In addition to operational constraints, network loss and physical limits are addressed in this model, which are always ignored in previous work. As an important component of Microgrid......, detailed combined heat and power (CHP) model is developed. The part load performance of CHP is modeled by curve fitting method. Furthermore, electric heater is introduced into the model to improve the economy of Microgrid operation and enhance the flexibility of the Microgrid by electricity-heat conversion....... Particle swarm optimization (PSO) is employed to solve this model for the operation schedule to minimize the total operational cost of Microgrid by coordinating the CHP, electric heater, boiler and heat storage. The efficacy of the model and methodology is verified with different operation scenarios....

  19. Mathematical Modelling and Parameter Optimization of Pulsating Heat Pipes

    CERN Document Server

    Yang, Xin-She; Luan, Tao; Koziel, Slawomir

    2014-01-01

    Proper heat transfer management is important to key electronic components in microelectronic applications. Pulsating heat pipes (PHP) can be an efficient solution to such heat transfer problems. However, mathematical modelling of a PHP system is still very challenging, due to the complexity and multiphysics nature of the system. In this work, we present a simplified, two-phase heat transfer model, and our analysis shows that it can make good predictions about startup characteristics. Furthermore, by considering parameter estimation as a nonlinear constrained optimization problem, we have used the firefly algorithm to find parameter estimates efficiently. We have also demonstrated that it is possible to obtain good estimates of key parameters using very limited experimental data.

  20. Tårs 10000 m2 CSP + Flat Plate Solar Collector Plant - Cost-Performance Optimization of the Design

    DEFF Research Database (Denmark)

    Perers, Bengt; Furbo, Simon; Tian, Zhiyong

    2016-01-01

    , was established. The optimization showed that there was a synergy in combining CSP and FP collectors. Even though the present cost per m² of the CSP collectors is high, the total energy cost is minimized by installing a combination of collectors in such solar heating plant. It was also found that the CSP...... collectors could raise flexibility in the control strategy of the plant. The TRNSYS-Genopt model is based on individually validated component models and collector parameters from experiments. Optimization of the cost performance of the plant has been conducted in this paper. The simulation model remains...... to be validated with annual measured data from the plant....

  1. Optimal Number of Thermoelectric Couples in a Heat Pipe Assisted Thermoelectric Generator for Waste Heat Recovery

    Science.gov (United States)

    Liu, Tongjun; Wang, Tongcai; Luan, Weiling; Cao, Qimin

    2017-01-01

    Waste heat recovery through thermoelectric generators is a promising way to improve energy conversion efficiency. This paper proposes a type of heat pipe assisted thermoelectric generator (HP-TEG) system. The expandable evaporator and condenser surface of the heat pipe facilitates the intensive assembly of thermoelectric (TE) modules to compose a compact device. Compared with a conventional layer structure thermoelectric generator, this system is feasible for the installment of more TE couples, thus increasing power output. To investigate the performance of the HP-TEG and the optimal number of TE couples, a theoretical model was presented and verified by experiment results. Further theoretical analysis results showed the performance of the HP-TEG could be further improved by optimizing the parameters, including the inlet air temperature, the thermal resistance of the heating section, and thermal resistance of the cooling structure. Moreover, applying a proper number of TE couples is important to acquire the best power output performance.

  2. Entropy generation extremum and entransy dissipation extremum for heat exchanger optimization

    Institute of Scientific and Technical Information of China (English)

    LIU XiongBin; MENG JiAn; GUO ZengYuan

    2009-01-01

    The applicability of the extremum principles of entropy generation and entransy dissipation is studied for heat exchanger optimization. The extremum principle of entransy dissipation gives better optimization results when heat exchanger is only for the purpose of heating and cooling, while the extremum principle of entropy generation is better for the heat exchanger optimization when it works in the Brayton cycle. The two optimization principles are approximately equivalent when the temperature drops of the streams in a heat exchanger are small.

  3. Finite time exergoeconomic performance optimization for an irreversible universal steady flow variable-temperature heat reservoir heat pump cycle model

    Directory of Open Access Journals (Sweden)

    Huijun Feng, Lingen Chen, Fengrui Sun

    2010-11-01

    Full Text Available An irreversible universal steady flow heat pump cycle model with variable-temperature heat reservoirs and the losses of heat-resistance and internal irreversibility is established by using the theory of finite time thermodynamics. The universal heat pump cycle model consists of two heat-absorbing branches, two heat-releasing branches and two adiabatic branches. Expressions of heating load, coefficient of performance (COP and profit rate of the universal heat pump cycle model are derived, respectively. By means of numerical calculations, heat conductance distributions between hot- and cold-side heat exchangers are optimized by taking the maximum profit rate as objective. There exist an optimal heat conductance distribution and an optimal thermal capacity rate matching between the working fluid and heat reservoirs which lead to a double maximum profit rate. The effects of internal irreversibility, total heat exchanger inventory, thermal capacity rate of the working fluid and heat capacity ratio of the heat reservoirs on the optimal finite time exergoeconomic performance of the cycle are discussed in detail. The results obtained herein include the optimal finite time exergoeconomic performances of endoreversible and irreversible, constant- and variable-temperature heat reservoir Brayton, Otto, Diesel, Atkinson, Dual, Miller and Carnot heat pump cycles.

  4. Cost-optimal levels of minimum energy performance requirements in the Danish Building Regulations

    Energy Technology Data Exchange (ETDEWEB)

    Aggerholm, S.

    2013-09-15

    The purpose of the report is to analyse the cost optimality of the energy requirements in the Danish Building Regulations 2010, BR10 to new building and to existing buildings undergoing major renovation. The energy requirements in the Danish Building Regulations have by tradition always been based on the cost and benefits related to the private economical or financial perspective. Macro economical calculations have in the past only been made in addition. The cost optimum used in this report is thus based on the financial perspective. Due to the high energy taxes in Denmark there is a significant difference between the consumer price and the macro economical for energy. Energy taxes are also paid by commercial consumers when the energy is used for building operation e.g. heating, lighting, ventilation etc. In relation to the new housing examples the present minimum energy requirements in BR 10 all shows gaps that are negative with a deviation of up till 16 % from the point of cost optimality. With the planned tightening of the requirements to new houses in 2015 and in 2020, the energy requirements can be expected to be tighter than the cost optimal point, if the costs for the needed improvements don't decrease correspondingly. In relation to the new office building there is a gap of 31 % to the point of cost optimality in relation to the 2010 requirement. In relation to the 2015 and 2020 requirements there are negative gaps to the point of cost optimality based on today's prices. If the gaps for all the new buildings are weighted to an average based on mix of building types and heat supply for new buildings in Denmark there is a gap of 3 % in average for the new building. The excessive tightness with today's prices is 34 % in relation to the 2015 requirement and 49 % in relation to the 2020 requirement. The component requirement to elements in the building envelope and to installations in existing buildings adds up to significant energy efficiency

  5. Effect of Heat Leak and Finite Thermal Capacity on the Optimal Configuration of a Two-Heat-Reservoir Heat Engine for Another Linear Heat Transfer Law

    Directory of Open Access Journals (Sweden)

    Chih Wu

    2003-12-01

    Full Text Available Abstract: Based on a model of a two-heat-reservoir heat engine with a finite high-temperature source and bypass heat leak, the optimal configuration of the cycle is found for the fixed cycle period with another linear heat transfer law . The finite thermal capacity source without heat leak makes the configuration of the cycle to a class of generalized Carnot cycle. The configuration of the cycle with heat leak and finite thermal capacity source is different from others.

  6. Optimization of the Heat Exchangers of a Thermoelectric Generation System

    Science.gov (United States)

    Martínez, A.; Vián, J. G.; Astrain, D.; Rodríguez, A.; Berrio, I.

    2010-09-01

    The thermal resistances of the heat exchangers have a strong influence on the electric power produced by a thermoelectric generator. In this work, the heat exchangers of a thermoelectric generator have been optimized in order to maximize the electric power generated. This thermoelectric generator harnesses heat from the exhaust gas of a domestic gas boiler. Statistical design of experiments was used to assess the influence of five factors on both the electric power generated and the pressure drop in the chimney: height of the generator, number of modules per meter of generator height, length of the fins of the hot-side heat exchanger (HSHE), length of the gap between fins of the HSHE, and base thickness of the HSHE. The electric power has been calculated using a computational model, whereas Fluent computational fluid dynamics (CFD) has been used to obtain the thermal resistances of the heat exchangers and the pressure drop. Finally, the thermoelectric generator has been optimized, taking into account the restrictions on the pressure drop.

  7. Research on optimal guaranteed cost control of flexible spacecraft

    Institute of Scientific and Technical Information of China (English)

    Wang Qingchao; Cai Peng

    2008-01-01

    This article is concerned with the modeling and control problems of the flexible spacecraft.First,the state observer is designed to estimate the vibration mode on the basis of free vibration models.Then,an optimal guaranteed cost controller is proposed to stabilize system attitude and damp the vibration of the flexible beam at the same time.Numerical simulation examples show the feasibility and validity of the proposed method.

  8. Cost optimal levels for energy performance requirements:Executive summary

    OpenAIRE

    Thomsen, Kirsten Engelund; Aggerholm, Søren; Kluttig-Erhorn, Heike; Erhorn, Hans; Poel, Bart; Hitchin, Roger

    2011-01-01

    This report summarises the work done within the Concerted Action EPBD from December 2010 to April 2011 in order to feed into the European Commission's proposal for a common European procedure for a Cost-Optimal methodology under the Directive on the Energy Performance of Buildings (recast) 2010/31/EU. This report summarises the work done within the Concerted Action EPBD from December 2010 to April 2011 in order to feed into the European Commission's proposal for a common European procedure...

  9. Cost Evaluation and Portfolio Management Optimization for Biopharmaceutical Product Development

    OpenAIRE

    Nie, W.

    2015-01-01

    The pharmaceutical industry is suffering from declining R&D productivity and yet biopharmaceutical firms have been attracting increasing venture capital investment. Effective R&D portfolio management can deliver above average returns under increasing costs of drug development and the high risk of clinical trial failure. This points to the need for advanced decisional tools that facilitate decision-making in R&D portfolio management by efficiently identifying optimal solutions while accounting...

  10. Optimization criteria, bounds, and efficiencies of heat engines.

    Science.gov (United States)

    Sánchez-Salas, N; López-Palacios, L; Velasco, S; Calvo Hernández, A

    2010-11-01

    The efficiency of four different and representative models of heat engines under maximum conditions for a figure of merit representing a compromise between useful energy and lost energy (the Ω criterion) is investigated and compared with previous results for the same models where the efficiency is considered at maximum power conditions. It is shown that the maximum Ω regime is more efficient and, additionally, that the resulting efficiencies present a similar behavior. For each performance regime we obtain explicit equations accounting for lower and upper bounds. The optimization of refrigeration devices is far from being as clear as heat engines, and some remarks on it are finally considered.

  11. Flash memories economic principles of performance, cost and reliability optimization

    CERN Document Server

    Richter, Detlev

    2014-01-01

    The subject of this book is to introduce a model-based quantitative performance indicator methodology applicable for performance, cost and reliability optimization of non-volatile memories. The complex example of flash memories is used to introduce and apply the methodology. It has been developed by the author based on an industrial 2-bit to 4-bit per cell flash development project. For the first time, design and cost aspects of 3D integration of flash memory are treated in this book. Cell, array, performance and reliability effects of flash memories are introduced and analyzed. Key performance parameters are derived to handle the flash complexity. A performance and array memory model is developed and a set of performance indicators characterizing architecture, cost and durability is defined.   Flash memories are selected to apply the Performance Indicator Methodology to quantify design and technology innovation. A graphical representation based on trend lines is introduced to support a requirement based pr...

  12. Current Cloud Computing Review and Cost Optimization by DERSP

    Directory of Open Access Journals (Sweden)

    M. Gomathy

    2014-03-01

    Full Text Available Cloud computing promises to deliver cost saving through the “pay as you use” paradigm. The focus is on adding computing resources when needed and releasing them when the need is serviced. Since cloud computing relies on providing computing power through multiple interconnected computers, there is a paradigm shift from one large machine to a combination of multiple smaller machine instances. In this paper, we review the current cloud computing scenario and provide a set of recommendations that can be used for designing custom applications suited for cloud deployment. We also present a comparative study on the change in cost incurred while using different combinations of machine instances for running an application on cloud; and derive the case for optimal cost

  13. Energy Cost Optimization in a Water Supply System Case Study

    Directory of Open Access Journals (Sweden)

    Daniel F. Moreira

    2013-01-01

    Full Text Available The majority of the life cycle costs (LCC of a pump are related to the energy spent in pumping, with the rest being related to the purchase and maintenance of the equipment. Any optimizations in the energy efficiency of the pumps result in a considerable reduction of the total operational cost. The Fátima water supply system in Portugal was analyzed in order to minimize its operational energy costs. Different pump characteristic curves were analyzed and modeled in order to achieve the most efficient operation point. To determine the best daily pumping operational scheduling pattern, genetic algorithm (GA optimization embedded in the modeling software was considered in contrast with a manual override (MO approach. The main goal was to determine which pumps and what daily scheduling allowed the best economical solution. At the end of the analysis it was possible to reduce the original daily energy costs by 43.7%. This was achieved by introducing more appropriate pumps and by intelligent programming of their operation. Given the heuristic nature of GAs, different approaches were employed and the most common errors were pinpointed, whereby this investigation can be used as a reference for similar future developments.

  14. Energy Analysis and Multi-Objective Optimization of an Internal Combustion Engine-Based CHP System for Heat Recovery

    Directory of Open Access Journals (Sweden)

    Abdolsaeid Ganjehkaviri

    2014-10-01

    Full Text Available A comprehensive thermodynamic study is conducted of a diesel based Combined Heat and Power (CHP system, based on a diesel engine and an Organic Rankine Cycle (ORC. Present research covers both energy and exergy analyses along with a multi-objective optimization. In order to determine the irreversibilities in each component of the CHP system and assess the system performance, a complete parametric study is performed to investigate the effects of major design parameters and operating conditions on the system’s performance. The main contribution of the current research study is to conduct both exergy and multi-objective optimization of a system using different working fluid for low-grade heat recovery. In order to conduct the evolutionary based optimization, two objective functions are considered in the optimization; namely the system exergy efficiency, and the total cost rate of the system, which is a combination of the cost associated with environmental impact and the purchase cost of each component. Therefore, in the optimization approach, the overall cycle exergy efficiency is maximized satisfying several constraints while the total cost rate of the system is minimized. To provide a better understanding of the system under study, the Pareto frontier is shown for multi-objective optimization and also an equation is derived to fit the optimized point. In addition, a closed form relationship between exergy efficiency and total cost rate is derived.

  15. 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.

  16. 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.

  17. Optimization of Combine Heat and Power Plants in the Russian Wholesale Power Market Conditions

    Directory of Open Access Journals (Sweden)

    I. A. Chuchueva

    2015-01-01

    Full Text Available The paper concerns the relevant problem to optimize the combine heat and power (CHP plants in the Russian wholesale power market conditions. Since 1975 the CHP plants specialists faced the problem of fuel rate or fuel cost reduction while ensuring the fixed level of heat and power production. The optimality criterion was the fuel rate or fuel cost which has to be minimized. Produced heat and power was paid by known tariff. Since the power market started in 2006 the power payment scheme has essentially changed: produced power is paid by market price. In such condition a new optimality criterion the paper offers is a profit which has to be maximized for the given time horizon. Depending on the optimization horizon the paper suggests four types of the problem urgency, namely: long-term, mid-term, short-term, and operative optimization. It clearly shows that the previous problem of fuel cost minimization is a special case of profit maximization problem. To bring the problem to the mixed-integer linear programming problem a new linear characteristic curves of steam and gas turbine are introduced. Error of linearization is 0.6%. The formal statement of the problem of short-term CHP plants optimization in the market conditions is offered. The problem was solved with IRM software (OpenLinkInternational for seven power plants of JSC “Quadra”: Dyagilevskaya CHP, Kurskaya CHP-1, Lipetskaya CHP-2, Orlovskaya CHP, Kurskaya CHP NWR, Tambovskaya CHP, and Smolenskaya CHP-2.The conducted computational experiment showed that a potential profit is between 1.7% and 4.7% of the fuel cost of different CHP plants and depends on the power plant operation conditions. The potential profit value is 2–3 times higher than analogous estimations, which were obtained solving fuel cost minimization problem. The perspectives of the work are formalization of mid-term and long-term CHP plants optimization problem and development of domestic software for the new problem

  18. Control and operation cost optimization of the HISS cryogenic system

    Science.gov (United States)

    Porter, J.; Bieser, F.; Anderson, D.

    1983-08-01

    The Heavy Ion Spectrometer System (HISS) relies upon superconducting coils of cryostable design to provide a maximum particle bending field of 3 tesla. A previous paper describes the cryogenic facility including helium refrigeration and gas management. A control strategy which has allowed full time unattended operation, along with significant nitrogen and power cost reductions is discussed. Reduction of liquid nitrogen consumption was accomplished by using the sensible heat available in the cold exhaust gas. Measured nitrogen throughput agrees with calculations for sensible heat utilization of zero to 70%. Calculated consumption saving over this range is 40 liters per hour for conductive losses to the supports only. It is found that the measured throughput differential for the total system is higher.

  19. Control and operation cost optimization of the HISS cryogenic system

    Energy Technology Data Exchange (ETDEWEB)

    Porter, J.; Bieser, F.; Anderson, D.

    1983-08-01

    The Heavy Ion Spectrometer System (HISS) relies upon superconducting coils of cryostable design to provide a maximum particle bending field of 3 tesla. A previous paper describes the cryogenic facility including helium refrigeration and gas management. This paper discusses a control strategy which has allowed full time unattended operation, along with significant nitrogen and power cost reductions. Reduction of liquid nitrogen consumption has been accomplished by making use of the sensible heat available in the cold exhaust gas. Measured nitrogen throughput agrees with calculations for sensible heat utilization of zero to 70%. Calculated consumption saving over this range is 40 liters per hour for conductive losses to the supports only. The measured throughput differential for the total system is higher.

  20. Cost Effectiveness Analysis of Optimal Malaria Control Strategies in Kenya

    Directory of Open Access Journals (Sweden)

    Gabriel Otieno

    2016-03-01

    Full Text Available Malaria remains a leading cause of mortality and morbidity among the children under five and pregnant women in sub-Saharan Africa, but it is preventable and controllable provided current recommended interventions are properly implemented. Better utilization of malaria intervention strategies will ensure the gain for the value for money and producing health improvements in the most cost effective way. The purpose of the value for money drive is to develop a better understanding (and better articulation of costs and results so that more informed, evidence-based choices could be made. Cost effectiveness analysis is carried out to inform decision makers on how to determine where to allocate resources for malaria interventions. This study carries out cost effective analysis of one or all possible combinations of the optimal malaria control strategies (Insecticide Treated Bednets—ITNs, Treatment, Indoor Residual Spray—IRS and Intermittent Preventive Treatment for Pregnant Women—IPTp for the four different transmission settings in order to assess the extent to which the intervention strategies are beneficial and cost effective. For the four different transmission settings in Kenya the optimal solution for the 15 strategies and their associated effectiveness are computed. Cost-effective analysis using Incremental Cost Effectiveness Ratio (ICER was done after ranking the strategies in order of the increasing effectiveness (total infections averted. The findings shows that for the endemic regions the combination of ITNs, IRS, and IPTp was the most cost-effective of all the combined strategies developed in this study for malaria disease control and prevention; for the epidemic prone areas is the combination of the treatment and IRS; for seasonal areas is the use of ITNs plus treatment; and for the low risk areas is the use of treatment only. Malaria transmission in Kenya can be minimized through tailor-made intervention strategies for malaria control

  1. Tool Steel Heat Treatment Optimization Using Neural Network Modeling

    Science.gov (United States)

    Podgornik, Bojan; Belič, Igor; Leskovšek, Vojteh; Godec, Matjaz

    2016-11-01

    Optimization of tool steel properties and corresponding heat treatment is mainly based on trial and error approach, which requires tremendous experimental work and resources. Therefore, there is a huge need for tools allowing prediction of mechanical properties of tool steels as a function of composition and heat treatment process variables. The aim of the present work was to explore the potential and possibilities of artificial neural network-based modeling to select and optimize vacuum heat treatment conditions depending on the hot work tool steel composition and required properties. In the current case training of the feedforward neural network with error backpropagation training scheme and four layers of neurons (8-20-20-2) scheme was based on the experimentally obtained tempering diagrams for ten different hot work tool steel compositions and at least two austenitizing temperatures. Results show that this type of modeling can be successfully used for detailed and multifunctional analysis of different influential parameters as well as to optimize heat treatment process of hot work tool steels depending on the composition. In terms of composition, V was found as the most beneficial alloying element increasing hardness and fracture toughness of hot work tool steel; Si, Mn, and Cr increase hardness but lead to reduced fracture toughness, while Mo has the opposite effect. Optimum concentration providing high KIc/HRC ratios would include 0.75 pct Si, 0.4 pct Mn, 5.1 pct Cr, 1.5 pct Mo, and 0.5 pct V, with the optimum heat treatment performed at lower austenitizing and intermediate tempering temperatures.

  2. Optimizing bulk milk dioxin monitoring based on costs and effectiveness.

    Science.gov (United States)

    Lascano-Alcoser, V H; Velthuis, A G J; van der Fels-Klerx, H J; Hoogenboom, L A P; Oude Lansink, A G J M

    2013-07-01

    Dioxins are environmental pollutants, potentially present in milk products, which have negative consequences for human health and for the firms and farms involved in the dairy chain. Dioxin monitoring in feed and food has been implemented to detect their presence and estimate their levels in food chains. However, the costs and effectiveness of such programs have not been evaluated. In this study, the costs and effectiveness of bulk milk dioxin monitoring in milk trucks were estimated to optimize the sampling and pooling monitoring strategies aimed at detecting at least 1 contaminated dairy farm out of 20,000 at a target dioxin concentration level. Incidents of different proportions, in terms of the number of contaminated farms, and concentrations were simulated. A combined testing strategy, consisting of screening and confirmatory methods, was assumed as well as testing of pooled samples. Two optimization models were built using linear programming. The first model aimed to minimize monitoring costs subject to a minimum required effectiveness of finding an incident, whereas the second model aimed to maximize the effectiveness for a given monitoring budget. Our results show that a high level of effectiveness is possible, but at high costs. Given specific assumptions, monitoring with 95% effectiveness to detect an incident of 1 contaminated farm at a dioxin concentration of 2 pg of toxic equivalents/g of fat [European Commission's (EC) action level] costs €2.6 million per month. At the same level of effectiveness, a 73% cost reduction is possible when aiming to detect an incident where 2 farms are contaminated at a dioxin concentration of 3 pg of toxic equivalents/g of fat (EC maximum level). With a fixed budget of €40,000 per month, the probability of detecting an incident with a single contaminated farm at a dioxin concentration equal to the EC action level is 4.4%. This probability almost doubled (8.0%) when aiming to detect the same incident but with a dioxin

  3. A Low Cost Structurally Optimized Design for Diverse Filter Types.

    Science.gov (United States)

    Kazmi, Majida; Aziz, Arshad; Akhtar, Pervez; Ikram, Nassar

    2016-01-01

    A wide range of image processing applications deploys two dimensional (2D)-filters for performing diversified tasks such as image enhancement, edge detection, noise suppression, multi scale decomposition and compression etc. All of these tasks require multiple type of 2D-filters simultaneously to acquire the desired results. The resource hungry conventional approach is not a viable option for implementing these computationally intensive 2D-filters especially in a resource constraint environment. Thus it calls for optimized solutions. Mostly the optimization of these filters are based on exploiting structural properties. A common shortcoming of all previously reported optimized approaches is their restricted applicability only for a specific filter type. These narrow scoped solutions completely disregard the versatility attribute of advanced image processing applications and in turn offset their effectiveness while implementing a complete application. This paper presents an efficient framework which exploits the structural properties of 2D-filters for effectually reducing its computational cost along with an added advantage of versatility for supporting diverse filter types. A composite symmetric filter structure is introduced which exploits the identities of quadrant and circular T-symmetries in two distinct filter regions simultaneously. These T-symmetries effectually reduce the number of filter coefficients and consequently its multipliers count. The proposed framework at the same time empowers this composite filter structure with additional capabilities of realizing all of its Ψ-symmetry based subtypes and also its special asymmetric filters case. The two-fold optimized framework thus reduces filter computational cost up to 75% as compared to the conventional approach as well as its versatility attribute not only supports diverse filter types but also offers further cost reduction via resource sharing for sequential implementation of diversified image

  4. A cost optimization model for 100% renewable residential energy supply systems

    DEFF Research Database (Denmark)

    Milan, Christian; Bojesen, Carsten; Nielsen, Mads Pagh

    2012-01-01

    's involving on-site production of heat and electricity in combination with electricity exchanged with the public grid. The model is based on linear programming and determines the optimal capacities for each relevant supply technology in terms of the overall system costs. It has been successfully applied......The concept of net zero energy buildings (Net ZEB) has received increased attention throughout the last years. A well adapted and optimized design of the energy supply system is crucial for the performance of these buildings. To achieve this, a holistic approach is needed which accounts...... for the interdependencies between the different supply technologies as well as the construction energy of the installations, consumption profiles and on-site energy resource availability. This paper aims at developing such a model for the optimal sizing of renewable energy supply systems (RES) for residential Net ZEB...

  5. Optimal allocation of watershed management cost among different water users

    Institute of Scientific and Technical Information of China (English)

    Wang Zanxin; Margaret M.Calderon

    2006-01-01

    The issue of water scarcity highlights the importance of watershed management. A sound watershed management should make all water users share the incurred cost. This study analyzes the optimal allocation of watershed management cost among different water users. As a consumable, water should be allocated to different users the amounts in which their marginal utilities (Mus) or marginal products (MPs) of water are equal. The value of Mus or MPs equals the water price that the watershed manager charges. When water is simultaneously used as consumable and non-consumable, the watershed manager produces the quantity of water in which the sum of Mus and/or MPs for the two types of uses equals the marginal cost of water production. Each water user should share the portion of watershed management cost in the percentage that his MU or MP accounts for the sum of Mus and/or MPs. Thus, the price of consumable water does not equal the marginal cost of water production even if there is no public good.

  6. Optimization of Boiler Heat Load in Water-Heating Boiler-House

    Directory of Open Access Journals (Sweden)

    B. A. Bayrashevsky

    2009-01-01

    Full Text Available An analytical method for optimization of water-heating boiler loads has been developed on the basis of approximated semi-empirical dependences pertaining to changes of boiler gross efficiency due to its load. A complex (∂tух/∂ξΔξ is determined on the basis of a systematic analysis (monitoring of experimental data and the Y. P. Pecker’s formula for calculation of balance losses q2. This complex makes it possible to set a corresponding correction to a standard value of the boiler gross efficiency due to contamination of heating surfaces.Software means for optimization of water-heating boilers has been developed and it is recommended to be applied under operational conditions.

  7. Linear versus quadratic portfolio optimization model with transaction cost

    Science.gov (United States)

    Razak, Norhidayah Bt Ab; Kamil, Karmila Hanim; Elias, Siti Masitah

    2014-06-01

    Optimization model is introduced to become one of the decision making tools in investment. Hence, it is always a big challenge for investors to select the best model that could fulfill their goal in investment with respect to risk and return. In this paper we aims to discuss and compare the portfolio allocation and performance generated by quadratic and linear portfolio optimization models namely of Markowitz and Maximin model respectively. The application of these models has been proven to be significant and popular among others. However transaction cost has been debated as one of the important aspects that should be considered for portfolio reallocation as portfolio return could be significantly reduced when transaction cost is taken into consideration. Therefore, recognizing the importance to consider transaction cost value when calculating portfolio' return, we formulate this paper by using data from Shariah compliant securities listed in Bursa Malaysia. It is expected that, results from this paper will effectively justify the advantage of one model to another and shed some lights in quest to find the best decision making tools in investment for individual investors.

  8. Application of entransy dissipation extremum principle in radiative heat transfer optimization

    Institute of Scientific and Technical Information of China (English)

    WU Jing; LIANG XinGang

    2008-01-01

    The concepts of entransy flux and entransy dissipation in radiative heat transfer were introduced based on the analogy with heat conduction and heat convection processes. Entransy will be partially dissipated during the radiative heat transfer processes due to the irreversibility. The extremum principle of entransy dissipation was developed for optimizing radiative heat transfer processes. This principle states that for a fixed boundary temperature the radiative heat transfer is optimized when the entransy dissipation is maximized, while for a fixed boundary heat flux the radiative heat transfer process is optimized when the entransy dissipation is minimized. Finally, examples for the application of the entransy dissipation extre-mum principle are presented.

  9. Application of entransy dissipation extremum principle in radiative heat transfer optimization

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The concepts of entransy flux and entransy dissipation in radiative heat transfer were introduced based on the analogy with heat conduction and heat convection processes. Entransy will be partially dissipated during the radiative heat transfer processes due to the irreversibility. The extremum principle of entransy dissipation was developed for optimizing radiative heat transfer processes. This principle states that for a fixed boundary temperature the radiative heat transfer is optimized when the entransy dissipation is maximized, while for a fixed boundary heat flux the radiative heat transfer process is optimized when the entransy dissipation is minimized. Finally, examples for the application of the entransy dissipation extre- mum principle are presented.

  10. Impacts of Various Characteristics of Electricity and Heat Demand on the Optimal Configuration of a Microgrid

    Science.gov (United States)

    Bando, Shigeru; Watanabe, Hiroki; Asano, Hiroshi; Tsujita, Shinsuke

    A methodology was developed to design the number and capacity for each piece of equipment (e.g. gas engines, batteries, thermal storage tanks) in microgrids with combined heat and power systems. We analyzed three types of microgrids; the first one consists of an office building and an apartment, the second one consists of a hospital and an apartment, the third one consists of a hotel, office and retails. In the methodology, annual cost is minimized by considering the partial load efficiency of a gas engine and its scale economy, and the optimal number and capacity of each piece of equipment and the annual operational schedule are determined by using the optimal planning method. Based on calculations using this design methodology, it is found that the optimal number of gas engines is determined by the ratio of bottom to peak of the electricity demand and the ratio of heat to electricity demand. The optimal capacity of a battery required to supply electricity for a limited time during a peak demand period is auxiliary. The thermal storage tank for space cooling and space heating is selected to minimize the use of auxiliary equipment such as a gas absorption chiller.

  11. Refrigeration Playbook. Heat Reclaim; Optimizing Heat Rejection and Refrigeration Heat Reclaim for Supermarket Energy Conservation

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Chuck [CTA Architects Engineers, Boise, ID (United States); Nelson, Eric [CTA Architects Engineers, Boise, ID (United States); Armer, James [CTA Architects Engineers, Boise, ID (United States); Johnson, Tim [CTA Architects Engineers, Boise, ID (United States); Hirsch, Adam [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Doebber, Ian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-03-01

    The purpose of this playbook and accompanying spreadsheets is to generalize the detailed CBP analysis and to put tools in the hands of experienced refrigeration designers to evaluate multiple applications of refrigeration waste heat reclaim across the United States. Supermarkets with large portfolios of similar buildings can use these tools to assess the impact of large-scale implementation of heat reclaim systems. In addition, the playbook provides best practices for implementing heat reclaim systems to achieve the best long-term performance possible. It includes guidance on operations and maintenance as well as measurement and verification.

  12. Additive Manufacturing for Cost Efficient Production of Compact Ceramic Heat Exchangers and Recuperators

    Energy Technology Data Exchange (ETDEWEB)

    Shulman, Holly [Ceralink Incorporated, Troy, NY (United States); Ross, Nicole [Ceralink Incorporated, Troy, NY (United States)

    2015-10-30

    An additive manufacture technique known as laminated object manufacturing (LOM) was used to fabricate compact ceramic heat exchanger prototypes. LOM uses precision CO2 laser cutting of ceramic green tapes, which are then precision stacked to build a 3D object with fine internal features. Modeling was used to develop prototype designs and predict the thermal response, stress, and efficiency in the ceramic heat exchangers. Build testing and materials analyses were used to provide feedback for the design selection. During this development process, laminated object manufacturing protocols were established. This included laser optimization, strategies for fine feature integrity, lamination fluid control, green handling, and firing profile. Three full size prototypes were fabricated using two different designs. One prototype was selected for performance testing. During testing, cross talk leakage prevented the application of a high pressure differential, however, the prototype was successful at withstanding the high temperature operating conditions (1300 °F). In addition, analysis showed that the bulk of the part did not have cracks or leakage issues. This led to the development of a module method for next generation LOM heat exchangers. A scale-up cost analysis showed that given a purpose built LOM system, these ceramic heat exchangers would be affordable for the applications.

  13. The cost-effectiveness of heat pumps in specific buildings in South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Greyvenstein, G.P.; Meyer, J.P. (Potchefstroom Univ. for CHE (South Africa). Dept. of Mechanical Engineering)

    1993-09-01

    Water heating heat pumps are extremely energy efficient and large savings can be realized when they are compared to direct electrical resistance heaters. In spite of the energy efficiency of heat pumps, a large number of residential buildings in South Africa still use electrical heaters to heat water. The reason for this is that heat pumps are considerably more expensive than electrical heaters. Building owners tend to choose the system with the smallest initial cost and do not compare the two systems on the basis of life-cycle cost. It is also difficult to calculate the life-cycle cost of a heat pump because it depends on many factors like climatological conditions and water temperature. In this paper a methodology is developed to calculate the life-cycle cost of a heat pump hot water installation. The model is used to investigate the effect of daily runtime, electricity tariff, hot water consumption and geographical location on the cost-effectiveness of heat pumps. The cost-effectiveness of heat pumps increases with daily run time, water consumption and electricity tariff. Heat pumps are more cost-effective near the coast than in the interior. If sized correctly, heat pumps are more cost-effective than electrical heaters for all major cities in South Africa. The cost-effectiveness of heat pumps for two specific buildings, one a university student hostel in Potchefstroom and the other a hotel in Durban, is also investigated. For both cases it was found that heat pumps are more cost-effective than direct electrical resistance heaters. (author)

  14. Solar water heating for aquaculture : optimizing design for sustainability

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, M.; Thwaites, J. [Taylor Munro Energy Systems Inc., Delta, BC (Canada)

    2003-08-01

    This paper presents the results of a solar water heating project at Redfish Ranch, the first Tilapia tropical fish farm in British Columbia. The fish are raised in land-based tanks, eliminating the risk of contamination of local ecosystems. As a tropical species, they requires warm water. Natural gas or propane boilers are typically used to maintain tank temperatures at 26 to 28 degrees C. Redfish Ranch uses solar energy to add heat to the fish tanks, thereby reducing fossil-fuel combustion and greenhouse gas emissions. This unique building-integrated solar system is improving the environmental status of of this progressive industrial operation by offsetting fossil-fuel consumption. The system was relatively low cost, although substantial changes had to be made to the roof of the main building. The building-integrated design of the solar water heating system has reduced operating costs, generated local employment, and shows promise of future activity. As such, it satisfies the main criteria for sustainability. 7 refs.

  15. Optimal configuration for a finite high-temperature source heat engine cycle with the complex heat transfer law

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The optimal configuration of a heat engine operating between a finite high-temperature source and an infinite low-temperature reservoir is derived by using finite time thermodynamics based on a complex heat transfer law,including Newtonian heat transfer law,linear phenomenological heat transfer law,radiative heat transfer law,Dulong-Petit heat transfer law,generalized convective heat transfer law and generalized radiative heat transfer law,q ∝(△T n). In the engine model the only irreversibility of finite rate heat transfer is considered. The optimal relation between the power output and efficiency of the heat engine is also derived by using an equivalent temperature of the hot reservoir. The obtained results include those obtained in recent literature and can provide some theoretical guidance for the designs of practical engines.

  16. Optimal configuration for a finite high-temperature source heat engine cycle with the complex heat transfer law

    Institute of Scientific and Technical Information of China (English)

    LI Jun; CHEN LinGen; SUN FengRui

    2009-01-01

    The optimal configuration of a heat engine operating between a finite high-temperature source and an infinite low-temperature reservoir is derived by using finite time thermodynamics based on a complex heat transfer law, including Newtonian heat transfer law, linear phenomenological heat transfer law, radiative heat transfer law, Dulong-Petit heat transfer law, generalized convective heat transfer law and generalized radiative heat transfer law, q∝ (△Tn). In the engine model the only irreversibility of finite rate heat transfer is considered. The optimal relation between the power output and efficiency of the heat engine is also derived by using an equivalent temperature of the hot reservoir. The obtained re-sults include those obtained in recent literature and can provide some theoretical guidance for the de-signs of practical engines.

  17. Exergy costing for energy saving in combined heating and cooling applications

    DEFF Research Database (Denmark)

    Nguyen, Chan; Veje, Christian T.; Willatzen, Morten

    2014-01-01

    The aim of this study is to provide a price model that motivates energy saving for a combined district heating and cooling system. A novel analysis using two thermoeconomic methods for apportioning the costs to heating and cooling provided simultaneously by an ammonia heat pump is demonstrated....... In the first method, referred to as energy costing, a conventional thermoeconomic analysis is used. Here the ammonia heat pump is subject to a thermodynamic analysis with mass and energy balance equations. In the second method referred to as exergy costing, an exergy based economic analysis is used, where....... The analysis shows that the two methods yield significantly different results. Rather surprisingly, it is demonstrated that the exergy costing method results in about three times higher unit cost for heating than for cooling as opposed to equal unit costs when using the energy method. Further the exergy-based...

  18. Optimization of Heat-Sink Cooling Structure in EAST with Hydraulic Expansion Technique%Optimization of Heat-Sink Cooling Structure in EAST with Hydraulic Expansion Technique

    Institute of Scientific and Technical Information of China (English)

    许铁军; 黄生洪; 谢韩; 宋云涛; 张平; 戢翔; 高大明

    2011-01-01

    Considering utilization of the original chromium-bronze material, two processing techniques including hydraulic expansion and high temperature vacuum welding were proposed for the optimization of heat-sink structure in EAST. The heat transfer performance of heat-sink with or without cooling tube was calculated and different types of connection between tube and heat-sink were compared by conducting a special test. It is shown from numerical analysis that the diameter of heat-sink channel can be reduced from 12 mm to 10 mm. Compared with the original sample, the thermal contact resistance between tube and heat-sink for welding sample can reduce the heat transfer performance by 10%, while by 20% for the hydraulic expansion sample. However, the welding technique is more complicated and expensive than hydraulic expansion technique. Both the processing technique and the heat transfer performance of heat-sink prototype should be further considered for the optimization of heat-sink structure in EAST.

  19. Application of optimization for improvement of the efficiency of louvered-fin compact heat exchangers

    Directory of Open Access Journals (Sweden)

    Diego Amorim Caetano Souza

    Full Text Available Abstract A few decades ago, the product development process was just based on a trial and error procedure, and the designer's experience. The need for a new way to design and manufacture more economical and sustainable products corroborates increasingly to a new vision of how to create new products for the benefit of society. Modern numerical tools allow greater knowledge about the physical phenomena involved in engineering problems and enable cost reduction with trials and time of manufacture and projection. Among the equipment that can be mentioned where numerical simulation is used, can be found heat exchangers, which are capable of accomplishing the heat transfer between two fluid medias with different temperatures. Within the range of existing exchangers, this work will address a compact model with louvered fins, widely used in the automotive and aerospace industries, mainly due to their high thermal exchange surface vs occupied volume ratio. The heat exchanger surface is analised using computational fluid dynamics tecniques disposable in the commercial code ANSYS CFX14® to reproduce the flow at service condition. Genetic optimization routines are used to increase the performance of heat exchanger. As a result, a heat transfer surface is obtained with about a 25% better performance according to the selected objective function. The dimensionless factor of the convective heat transfer coefficient (Colburn factor, j and the friction factor (Fanning factor, f used in (Wang et al.,1998, are employed for simulation. Experimental data are also used for validation.

  20. Cost-Optimal Pathways to 75% Fuel Reduction in Remote Alaskan Villages: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Simpkins, Travis; Cutler, Dylan; Hirsch, Brian; Olis, Dan; Anderson, Kate

    2015-10-28

    There are thousands of isolated, diesel-powered microgrids that deliver energy to remote communities around the world at very high energy costs. The Remote Communities Renewable Energy program aims to help these communities reduce their fuel consumption and lower their energy costs through the use of high penetration renewable energy. As part of this program, the REopt modeling platform for energy system integration and optimization was used to analyze cost-optimal pathways toward achieving a combined 75% reduction in diesel fuel and fuel oil consumption in a select Alaskan village. In addition to the existing diesel generator and fuel oil heating technologies, the model was able to select from among wind, battery storage, and dispatchable electric heaters to meet the electrical and thermal loads. The model results indicate that while 75% fuel reduction appears to be technically feasible it may not be economically viable at this time. When the fuel reduction target was relaxed, the results indicate that by installing high-penetration renewable energy, the community could lower their energy costs by 21% while still reducing their fuel consumption by 54%.

  1. evaluation of total annual costs of heat exchanger networks using ...

    African Journals Online (AJOL)

    user

    This study presents pinch analysis of some heat exchanger networks (HENs) problems using Hint integration .... of chemical process design for the conversion of raw materials to ... task is to synthesis a heat exchanger network that will.

  2. Acoustic Optimization of Automotive Exhaust Heat Thermoelectric Generator

    Science.gov (United States)

    Su, C. Q.; Ye, B. Q.; Guo, X.; Hui, P.

    2012-06-01

    The potential for thermoelectric exhaust heat recovery in vehicles has been increasing with recent advances in the efficiency of thermoelectric generators (TEGs). This study analyzes the acoustic attenuation performance of exhaust-based TEGs. The acoustic characteristics of two different thermal designs of exhaust gas heat exchanger in TEGs are discussed in terms of transmission loss and acoustic insertion loss. GT-Power simulations and bench tests on a dynamometer with a high-performance production engine are carried out. Results indicate that the acoustic attenuation of TEGs could be determined and optimized. In addition, the feasibility of integration of exhaust-based TEGs and engine mufflers into the exhaust line is tested, which can help to reduce space and improve vehicle integration.

  3. Optimal operation of integrated processes. Studies on heat recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Glemmestad, Bjoern

    1997-12-31

    Separators, reactors and a heat exchanger network (HEN) for heat recovery are important parts of an integrated plant. This thesis deals with the operation of HENs, in particular, optimal operation. The purpose of heat integration is to save energy, but the HEN also introduces new interactions and feedback into the overall plant. A prerequisite for optimisation is that there are extra degrees of freedom left after regulatory control is implemented. It is shown that extra degrees of freedom may not always be utilized for energy optimisation, and a quantitative expression for the degrees of freedom that can be so utilized are presented. A simplified expression that is often valid is also deduced. The thesis presents some improvements and generalisations of a structure based method that has been proposed earlier. Structural information is used to divide possible manipulations into three categories depending on how each manipulation affects the utility consumption. By means of these categories and two heuristic rules for operability, the possible manipulations are ordered in a priority table. This table is used to determine which manipulation should be preferred and which manipulation should be selected if an active manipulation is saturated. It is shown that the method may correspond to split-range control. A method that uses parametric information in addition to structural information is proposed. In this method, the optimal control structure is found through solving an integer programming problem. The thesis also proposes a method that combines the use of steady state optimisation and optimal selection of measurements. 86 refs., 46 figs., 8 tabs.

  4. Moisture-heating Treatment and Processing Optimization of Parboiled Rice

    Institute of Scientific and Technical Information of China (English)

    Zhao Siming; Xiong Shanbai

    2001-01-01

    Effect of moisture-heating treatment on the quality of parboiled rice and processing optimization were studied. Results indicated that the riboflavine content of parboiled rice is higher, and the color is light, aroma is strong and the head yield ratio is higher by soaking with acid and ethanol, cooking at high-pressure and then drying with high temperature-high moisture. Optimal processing parameters are soaking paddy with citrate acid for 2h, then with 1.5% ethanol for 1.5h, high pressure cooking for 30min, and then drying under 55%RH, 90℃ for 30min, cooling slowly for 2.5h, and shelling and milling immediately. Head yield ratio and whole rice ratio was 67.3% and 87.0% respectively, the color of finished product is light, rice aroma is strong, and the content of riboflavine is 2.47mg/100g.

  5. Moisture-heating Treatment and Processing Optimization of Parboiled Rice

    Institute of Scientific and Technical Information of China (English)

    ZhaoSiming; XiongShanbai

    2001-01-01

    Abstract: Effect of moisture-heating treatment on the quality ofparboiled rice and processing optimization were studied. Resultsindicated that the riboflavine content of parboiled rice is higher, and thecolor is light, aroma is strong and the head yield ratio is higher bysoaking with acid and ethanol, cooking at high-pressure and thendrying with high temperature-high moisture. Optimal processingparameters are soaking paddy with citrate acid for 2h, then with 1.5%ethanol for 1.5h, high pressure cooking for 30min, and then dryingunder 55%RH, 90~C for 30min, cooling slowly for 2.5h, and shelling andmilling immediately. Head yield ratio and whole rice ratio was 67.3%and 87.0% respectively, the color of finished product is light, ricearoma is strong, and the content of riboflavine is 2.47mg/100g.

  6. An Optimal Solution of Resource Provisioning Cost in Cloud Computing Environments

    Directory of Open Access Journals (Sweden)

    Arun Pandian

    2013-03-01

    Full Text Available In cloud computing, providing an optimal resource to user becomes more and more important. Cloud computing users can access the pool of computing resources through internet. Cloud providers are charge for these computing resources based on cloud resource usage. The provided resource plans are reservation and on demand. The computing resources are provisioned by cloud resource provisioning model. In this model resource cost is high due to the difficulty in optimization of resource cost under uncertainty. The resource optimization cost is dealing with an uncertainty of resource provisioning cost. The uncertainty of resource provisioning cost consists: on demand cost, Reservation cost, Expending cost. This problem leads difficulty to achieve optimal solution of resource provisioning cost in cloud computing. The Stochastic Integer Programming is applied for difficulty to obtain optimal resource provisioning cost. The Two Stage Stochastic Integer Programming with recourse is applied to solve the complexity of optimization problems under uncertainty. The stochastic programming is enhanced as Deterministic Equivalent Formulation for solve the probability distribution of all scenarios to reduce the on demand cost. The Benders Decomposition is applied for break down the resource optimization problem into multiple sub problems to reduce the on demand cost and reservation cost. The Sample Average Approximation is applied for reduce the problem scenarios in a resource optimization problem. This algorithm is used to reduce the reservation cost and expending cost.

  7. Influence of heat cost allocation on occupants' control of indoor environment in 56 apartments

    DEFF Research Database (Denmark)

    Andersen, Søren; Andersen, Rune Korsholm; Olesen, Bjarne W.

    2016-01-01

    by comparing indoor environmental measurements between two buildings: one with collective payment and one with individual payment. The measurements were collected at 5 min intervals at a central location in each of 56 apartments in Copenhagen, Denmark over a period of two months. Questionnaires and semi......-structured interviews showed a strong influence of the heat cost allocation plan on the occupants' control strategies. Occupants whose heating bills were based on floor area focused on a healthy and comfortable indoor environment. Occupants whose heating bills were based on meter readings focused on energy conservation...... of this paper was to study the indoor environment in buildings with collective and individual heat cost allocation plans, to investigate how the heat cost allocation influenced occupant behaviour and how occupants controlled the indoor environment. The effects of the heat cost allocation type were studied...

  8. Optimally controlled heating of solid particles in a fluidised bed with a dispersive flow of the solid

    Directory of Open Access Journals (Sweden)

    Poświata Artur

    2016-03-01

    Full Text Available In this study the authors minimise the total process cost for the heating of solid particles in a horizontal fluidised bed by an optimal choice of the inlet heating gas temperature profile and the total gas flow. Solid particles flowed along the apparatus and were heated by a hot gas entering from the bottom of the fluidised apparatus. The hydrodynamics of the fluidised bed is described by a two-phase Kunii - Levenspiel model. We assumed that the gas was flowing only vertically, whereas solid particles were flowing horizontally and because of dispersion they could be additionally mixed up in the same direction. The mixing rate was described by the axial dispersion coefficient. As any economic values of variables describing analysing process are subject to local and time fluctuations, the accepted objective function describes the total cost of the process expressed in exergy units. The continuous optimisation algorithm of the Maximum Principle was used for calculations. A mathematical model of the process, including boundary conditions in a form convenient for optimisation, was derived and presented. The optimization results are presented as an optimal profile of inlet gas temperature. The influence of heat transfer kinetics and dispersion coefficients on optimal runs of the heating process is discussed. Results of this discussion constitute a novelty in comparison to information presented in current literature.

  9. 16 CFR Appendix I to Part 305 - Heating Performance and Cost for Central Air Conditioners

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Heating Performance and Cost for Central Air Conditioners I Appendix I to Part 305 Commercial Practices FEDERAL TRADE COMMISSION REGULATIONS UNDER SPECIFIC... Manufacturer's rated heating capacity (Btu's/hr.) Range of HSPF's Low High Single Package Units Heat Pumps...

  10. Optimization of costs in the lighting planning. Total cost of ownership of a lighting device; Kosten optimieren bei der Lichtplanung. Total Cost of Ownership einer Beleuchtungsanlage

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Elke

    2010-11-15

    Not only the initial costs, but also the total costs in the life cycle of the plant are crucial for economical lighting devices. Apart from the acquisition, the perspective 'Total Cost of Ownership' covers the costs of energy, replacement lamps and maintenance. Likewise, indirect follow-up costs such as additional expenditure for air conditioning are considered in order to compensate the heat load of the lighting.

  11. Low Cost Advanced Thermoelectric (TE) Technology for Automotive Waste Heat Recovery

    Science.gov (United States)

    Meisner, G. P.

    2014-03-01

    Low cost, fully integrated TE generators (TEGs) to recover waste heat from vehicle exhaust will reduce transportation sector energy consumption and emissions. TEGs will be the first application of high-temperature TE materials for high-volume use and establish new industrial sectors with scaled up production capability of TEG materials and components. We will create a potential supply chain for practical automotive TEGs and identify manufacturing and assembly processes for large scale production of TEG materials and components. Our work focusses on several innovative R&D paths: (1) enhanced TE material performance by doping and compositional tuning, (2) optimized TE material fabrication and processing to reduce thermal conductivity and improve fracture strength, (3) high volume production for successful skutterudite commercialization, (4) new material, nanostructure, and nanoscale approaches to reduce thermal interface and electrical contact resistances, (5) innovative heat exchangers for high efficiency heat flows and optimum temperature profiles despite highly variable exhaust gas operating conditions, (6) new modeling and simulation tools, and (7) inexpensive materials for thermal insulation and coatings for TE encapsulation. Recent results will be presented. Supported by the U.S. DOE Vehicle Technology Program.

  12. Optimal selection of on-site generation with combined heat andpower applications

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, Afzal S.; Marnay, Chris; Bailey, Owen; HamachiLaCommare, Kristina

    2004-11-30

    While demand for electricity continues to grow, expansion of the traditional electricity supply system, or macrogrid, is constrained and is unlikely to keep pace with the growing thirst western economies have for electricity. Furthermore, no compelling case has been made that perpetual improvement in the overall power quality and reliability (PQR)delivered is technically possible or economically desirable. An alternative path to providing high PQR for sensitive loads would generate close to them in microgrids, such as the Consortium for Electricity Reliability Technology Solutions (CERTS) Microgrid. Distributed generation would alleviate the pressure for endless improvement in macrogrid PQR and might allow the establishment of a sounder economically based level of universal grid service. Energy conversion from available fuels to electricity close to loads can also provide combined heat and power (CHP) opportunities that can significantly improve the economics of small-scale on-site power generation, especially in hot climates when the waste heat serves absorption cycle cooling equipment that displaces expensive on-peak electricity. An optimization model, the Distributed Energy Resources Customer Adoption Model (DER-CAM), developed at Berkeley Lab identifies the energy bill minimizing combination of on-site generation and heat recovery equipment for sites, given their electricity and heat requirements, the tariffs they face, and a menu of available equipment. DER-CAM is used to conduct a systemic energy analysis of a southern California naval base building and demonstrates atypical current economic on-site power opportunity. Results achieve cost reductions of about 15 percent with DER, depending on the tariff.Furthermore, almost all of the energy is provided on-site, indicating that modest cost savings can be achieved when the microgrid is free to select distributed generation and heat recovery equipment in order to minimize its over all costs.

  13. Optimal configuration of a class of endoreversible heat engines for maximum efficiency with radiative heat transfer law

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Optimal configuration of a class of endoreversible heat engines with fixed duration,input energy and radiative heat transfer law (q∝Δ(T4)) is determined. The optimal cycle that maximizes the efficiency of the heat engine is obtained by using opti-mal-control theory,and the differential equations are solved by the Taylor series expansion. It is shown that the optimal cycle has eight branches including two isothermal branches,four maximum-efficiency branches,and two adiabatic branches. The interval of each branch is obtained,as well as the solutions of the temperatures of the heat reservoirs and the working fluid. A numerical example is given. The obtained results are compared with those obtained with the Newton’s heat transfer law for the maximum efficiency objective,those with linear phe-nomenological heat transfer law for the maximum efficiency objective,and those with radiative heat transfer law for the maximum power output objective.

  14. Optimal configuration of a class of endoreversible heat engines for maximum efficiency with radiative heat transfer law

    Institute of Scientific and Technical Information of China (English)

    SONG HanJiang; CHEN LinGen; SUN FengRui

    2008-01-01

    Optimal configuration of a class of endoreversible heat engines with fixed duration, input energy and radiative heat transfer law (q∝△(T4)) is determined. The optimal cycle that maximizes the efficiency of the heat engine is obtained by using opti-mal-control theory, and the differential equations are solved by the Taylor series expansion. It is shown that the optimal cycle has eight branches including two isothermal branches, four maximum-efficiency branches, and two adiabatic branches. The interval of each branch is obtained, as well as the solutions of the temperatures of the heat reservoirs and the working fluid. A numerical example is given. The obtained results are compared with those obtained with the Newton's heat transfer law for the maximum efficiency objective, those with linear phe-nomenological heat transfer law for the maximum efficiency objective, and those with radiative heat transfer law for the maximum power output objective.

  15. Life Cycle Cost Optimization of a Bolig+ Zero Energy Building

    DEFF Research Database (Denmark)

    Marszal, Anna Joanna

    in the Danish context. The review of the various ZEB approaches indicated a general concept of a Zero Energy Building as a building with significantly reduced energy demand that isbalanced by an equivalent energy generation from renewable sources. And, with this as a general framework, each ZEB definition...... should further specify: (1) the connection orthe lack of it to the energy infrastructure, (2) the unit of the balance, (3) the period of the balance, (4) the types of energy use included in the balance, (5) the minimumenergy performance requirements (6) the renewable energy supply options...... case of a multi-storey residential Net ZEB aimed to determine the cost-optimal “zero” energy balance,minimum energy performance requirements and options of supplying renewable energy. The calculation encompassed three levels of energy frames, which mirrored theDanish low-energy building classes...

  16. Experimental Optimization of Passive Cooling of a Heat Source Array Flush-Mounted on a Vertical Plate

    Directory of Open Access Journals (Sweden)

    Antoine Baudoin

    2016-11-01

    Full Text Available Heat sources, such as power electronics for offshore power, could be cooled passively—mainly by conduction and natural convection. The obvious advantage of this strategy is its high reliability. However, it must be implemented in an efficient manner (i.e., the area needs to be kept low to limit the construction costs. In this study, the placement of multiple heat sources mounted on a vertical plate was studied experimentally for optimization purposes. We chose a regular distribution, as this is likely to be the preferred choice in the construction process. We found that optimal spacing can be determined for a targeted source density by tuning the vertical and horizontal spacing between the heat sources. The optimal aspect ratio was estimated to be around two.

  17. Multi-Objective Optimization Design for Indirect Forced-Circulation Solar Water Heating System Using NSGA-II

    Directory of Open Access Journals (Sweden)

    Myeong Jin Ko

    2015-11-01

    Full Text Available In this study, the multi-objective optimization of an indirect forced-circulation solar water heating (SWH system was performed to obtain the optimal configuration that minimized the life cycle cost (LCC and maximized the life cycle net energy saving (LCES. An elitist non-dominated sorting genetic algorithm (NSGA-II was employed to obtain the Pareto optimal solutions of the multi-objective optimization. To incorporate the characteristics of practical SWH systems, operation-related decision variables as well as capacity-related decision variables were included. The proposed method was used to conduct a case study wherein the optimal configuration of the SWH system of an office building was determined. The case study results showed that the energy cost decreases linearly and the equipment cost increases more significantly as the LCES increases. However, the results also showed that it is difficult to identify the best solution among the Pareto optimal solutions using only the correlation between the corresponding objective function values. Furthermore, regression analysis showed that the energy and economic performances of the Pareto optimal solutions are significantly influenced by the ratio of the storage tank volume to the collector area (RVA. Therefore, it is necessary to simultaneously consider the trade-off and the effect of the RVA on the Pareto optimal solutions while selecting the best solution from among the optimal solutions.

  18. Environmentally friendly heat from modern heating technology. Optimal heat distribution using jet pumps; Umweltschonende Waerme durch moderne Heiztechnik. Optimale Waermeverteilung mit Strahlpumpen

    Energy Technology Data Exchange (ETDEWEB)

    Kilpper, Renate; Baelz, Uwe [W. Baelz und Sohn GmbH und Co., Heilbronn (Germany)

    2011-07-15

    The wood chip fired district heating plant in Olang in South Tyrol produces environmentally friendly heat from domestic wood. Its heat is delivered directly to the consumer using electricity-saving, durable jet pumps in combination with reliable, low-maintenance heating equipment as well as modern control technology. Consumers can regulate the jet pumps individually and use the heat optimally according to their demand.

  19. Optimal Investment Under Transaction Costs: A Threshold Rebalanced Portfolio Approach

    Science.gov (United States)

    Tunc, Sait; Donmez, Mehmet Ali; Kozat, Suleyman Serdar

    2013-06-01

    We study optimal investment in a financial market having a finite number of assets from a signal processing perspective. We investigate how an investor should distribute capital over these assets and when he should reallocate the distribution of the funds over these assets to maximize the cumulative wealth over any investment period. In particular, we introduce a portfolio selection algorithm that maximizes the expected cumulative wealth in i.i.d. two-asset discrete-time markets where the market levies proportional transaction costs in buying and selling stocks. We achieve this using "threshold rebalanced portfolios", where trading occurs only if the portfolio breaches certain thresholds. Under the assumption that the relative price sequences have log-normal distribution from the Black-Scholes model, we evaluate the expected wealth under proportional transaction costs and find the threshold rebalanced portfolio that achieves the maximal expected cumulative wealth over any investment period. Our derivations can be readily extended to markets having more than two stocks, where these extensions are pointed out in the paper. As predicted from our derivations, we significantly improve the achieved wealth over portfolio selection algorithms from the literature on historical data sets.

  20. Cost Optimization of Cloud Computing Services in a Networked Environment

    Directory of Open Access Journals (Sweden)

    Eli WEINTRAUB

    2015-04-01

    Full Text Available Cloud computing service providers' offer their customers' services maximizing their revenues, whereas customers wish to minimize their costs. In this paper we shall concentrate on consumers' point of view. Cloud computing services are composed of services organized according to a hierarchy of software application services, beneath them platform services which also use infrastructure services. Providers currently offer software services as bundles consisting of services which include the software, platform and infrastructure services. Providers also offer platform services bundled with infrastructure services. Bundling services prevent customers from splitting their service purchases between a provider of software and a different provider of the underlying platform or infrastructure. This bundling policy is likely to change in the long run since it contradicts economic competition theory, causing an unfair pricing model and locking-in consumers to specific service providers. In this paper we assume the existence of a free competitive market, in which consumers are free to switch their services among providers. We assume that free market competition will enforce vendors to adopt open standards, improve the quality of their services and suggest a large variety of cloud services in all layers. Our model is aimed at the potential customer who wishes to find the optimal combination of service providers which minimizes his costs. We propose three possible strategies for implementation of the model in organizations. We formulate the mathematical model and illustrate its advantages compared to existing pricing practices used by cloud computing consumers.

  1. Particle swarm optimization algorithm based low cost magnetometer calibration

    Science.gov (United States)

    Ali, A. S.; Siddharth, S., Syed, Z., El-Sheimy, N.

    2011-12-01

    Inertial Navigation Systems (INS) consist of accelerometers, gyroscopes and a microprocessor provide inertial digital data from which position and orientation is obtained by integrating the specific forces and rotation rates. In addition to the accelerometers and gyroscopes, magnetometers can be used to derive the absolute user heading based on Earth's magnetic field. Unfortunately, the measurements of the magnetic field obtained with low cost sensors are corrupted by several errors including manufacturing defects and external electro-magnetic fields. Consequently, proper calibration of the magnetometer is required to achieve high accuracy heading measurements. In this paper, a Particle Swarm Optimization (PSO) based calibration algorithm is presented to estimate the values of the bias and scale factor of low cost magnetometer. The main advantage of this technique is the use of the artificial intelligence which does not need any error modeling or awareness of the nonlinearity. The estimated bias and scale factor errors from the proposed algorithm improve the heading accuracy and the results are also statistically significant. Also, it can help in the development of the Pedestrian Navigation Devices (PNDs) when combined with the INS and GPS/Wi-Fi especially in the indoor environments

  2. Aircraft path planning for optimal imaging using dynamic cost functions

    Science.gov (United States)

    Christie, Gordon; Chaudhry, Haseeb; Kochersberger, Kevin

    2015-05-01

    Unmanned aircraft development has accelerated with recent technological improvements in sensing and communications, which has resulted in an "applications lag" for how these aircraft can best be utilized. The aircraft are becoming smaller, more maneuverable and have longer endurance to perform sensing and sampling missions, but operating them aggressively to exploit these capabilities has not been a primary focus in unmanned systems development. This paper addresses a means of aerial vehicle path planning to provide a realistic optimal path in acquiring imagery for structure from motion (SfM) reconstructions and performing radiation surveys. This method will allow SfM reconstructions to occur accurately and with minimal flight time so that the reconstructions can be executed efficiently. An assumption is made that we have 3D point cloud data available prior to the flight. A discrete set of scan lines are proposed for the given area that are scored based on visibility of the scene. Our approach finds a time-efficient path and calculates trajectories between scan lines and over obstacles encountered along those scan lines. Aircraft dynamics are incorporated into the path planning algorithm as dynamic cost functions to create optimal imaging paths in minimum time. Simulations of the path planning algorithm are shown for an urban environment. We also present our approach for image-based terrain mapping, which is able to efficiently perform a 3D reconstruction of a large area without the use of GPS data.

  3. Optimal design of divertor heat sink with different geometric configurations of sectorial extended surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rimza, Sandeep, E-mail: sandeepr@ipr.res.in [Divertor and First Wall Technology Development Division, Institute for Plasma Research (IPR), Bhat – 382428, Gandhinagar, Gujarat (India); Satpathy, Kamalakanta, E-mail: satpathy@ipr.res.in [Divertor and First Wall Technology Development Division, Institute for Plasma Research (IPR), Bhat – 382428, Gandhinagar, Gujarat (India); Khirwadkar, Samir, E-mail: sameer@ipr.res.in [Divertor and First Wall Technology Development Division, Institute for Plasma Research (IPR), Bhat – 382428, Gandhinagar, Gujarat (India); Velusamy, Karupanna, E-mail: kvelu@igcar.gov.in [Mechanics and Hydraulics Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603102 (India)

    2015-11-15

    Highlights: • Effect of design variables in enhancing heat removal potential with pumping power assessed. • The optimization objective is to minimize the thimble temperature. • Investigation of optimum design parameters for various Reynolds number. • Practicability of the optimum designs is verified through structural analysis. • Benchmark validation of divertor finger mock-up against in-house experiment and good agreement is achieved. - Abstract: Cooling of fusion reactor divertor by helium is widely accepted due to its chemical and neutronic inertness and superior safety aspect. However, its poor thermo physical characteristics need high pressure to remove large heat flux encountered in fusion power plant (DEMO). In the perspective of DEMO, it is desirable to explore efficient cooling technology for divertor that can handle high heat flux. Toward this, a novel sectorial extended surface (SES) was proposed by the authors Rimza et al. (2014) [2]. The present work focuses on design optimization of divertor finger mock-up with SES to enhance the thermal hydraulic performance. The maximum thimble temperature is considered as the vital design constraint. Various non-dimensional design variables, viz., relative pitch, thickness, jet diameter, the ratio of height of SES to jet diameter and circumferential position of the SES are considered for the present optimization study. The effects of design variables on thermal performance of the divertor are evaluated in the Reynolds number (Re) range of 7.5 × 10{sup 4}–1.2 × 10{sup 5}. The analysis reveals that, the heat transfer performance of divertor finger mock-up with SES is improved for two optimum designs having relative pitch and thickness of 0.30 and 0.56, respectively. Also, it is observed that finger mock-up heat sink with SES performs better, when the ratio of SES height to jet diameter, reduces to 0.75 at the cost of marginally higher pumping power. The effects of jet diameter and circumferential

  4. Cost Optimal Elastic Auto-Scaling in Cloud Infrastructure

    Science.gov (United States)

    Mukhopadhyay, S.; Sidhanta, S.; Ganguly, S.; Nemani, R. R.

    2014-12-01

    Today, elastic scaling is critical part of leveraging cloud. Elastic scaling refers to adding resources only when it is needed and deleting resources when not in use. Elastic scaling ensures compute/server resources are not over provisioned. Today, Amazon and Windows Azure are the only two platform provider that allow auto-scaling of cloud resources where servers are automatically added and deleted. However, these solution falls short of following key features: A) Requires explicit policy definition such server load and therefore lacks any predictive intelligence to make optimal decision; B) Does not decide on the right size of resource and thereby does not result in cost optimal resource pool. In a typical cloud deployment model, we consider two types of application scenario: A. Batch processing jobs → Hadoop/Big Data case B. Transactional applications → Any application that process continuous transactions (Requests/response) In reference of classical queuing model, we are trying to model a scenario where servers have a price and capacity (size) and system can add delete servers to maintain a certain queue length. Classical queueing models applies to scenario where number of servers are constant. So we cannot apply stationary system analysis in this case. We investigate the following questions 1. Can we define Job queue and use the metric to define such a queue to predict the resource requirement in a quasi-stationary way? Can we map that into an optimal sizing problem? 2. Do we need to get into a level of load (CPU/Data) on server level to characterize the size requirement? How do we learn that based on Job type?

  5. Heuristic Optimization of Consumer Electricity Costs Using a Generic Cost Model

    Directory of Open Access Journals (Sweden)

    Chris Ogwumike

    2015-12-01

    Full Text Available Many new demand response strategies are emerging for energy management in smart grids. Real-Time Energy Pricing (RTP is one important aspect of consumer Demand Side Management (DSM, which encourages consumers to participate in load scheduling. This can help reduce peak demand and improve power system efficiency. The use of Intelligent Decision Support Systems (IDSSs for load scheduling has become necessary in order to enable consumers to respond to the changing economic value of energy across different hours of the day. The type of scheduling problem encountered by a consumer IDSS is typically NP-hard, which warrants the search for good heuristics with efficient computational performance and ease of implementation. This paper presents an extensive evaluation of a heuristic scheduling algorithm for use in a consumer IDSS. A generic cost model for hourly pricing is utilized, which can be configured for traditional on/off peak pricing, RTP, Time of Use Pricing (TOUP, Two-Tier Pricing (2TP and combinations thereof. The heuristic greedily schedules controllable appliances to minimize smart appliance energy costs and has a polynomial worst-case computation time. Extensive computational experiments demonstrate the effectiveness of the algorithm and the obtained results indicate the gaps between the optimal achievable costs are negligible.

  6. Color tunable low cost transparent heat reflector using copper and titanium oxide for energy saving application.

    Science.gov (United States)

    Dalapati, Goutam Kumar; Masudy-Panah, Saeid; Chua, Sing Teng; Sharma, Mohit; Wong, Ten It; Tan, Hui Ru; Chi, Dongzhi

    2016-02-05

    Multilayer coating structure comprising a copper (Cu) layer sandwiched between titanium dioxide (TiO2) were demonstrated as a transparent heat reflecting (THR) coating on glass for energy-saving window application. The main highlight is the utilization of Cu, a low-cost material, in-lieu of silver which is widely used in current commercial heat reflecting coating on glass. Color tunable transparent heat reflecting coating was realized through the design of multilayer structure and process optimization. The impact of thermal treatment on the overall performance of sputter deposited TiO2/Cu/TiO2 multilayer thin film on glass substrate is investigated in detail. Significant enhancement of transmittance in the visible range and reflectance in the infra-red (IR) region has been observed after thermal treatment of TiO2/Cu/TiO2 multilayer thin film at 500 °C due to the improvement of crystal quality of TiO2. Highest visible transmittance of 90% and IR reflectance of 85% at a wavelength of 1200 nm are demonstrated for the TiO2/Cu/TiO2 multilayer thin film after annealing at 500 °C. Performance of TiO2/Cu/TiO2 heat reflector coating decreases after thermal treatment at 600 °C. The wear performance of the TiO2/Cu/TiO2 multilayer structure has been evaluated through scratch hardness test. The present work shows promising characteristics of Cu-based THR coating for energy-saving building industry.

  7. 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

  8. Computer simulation and optimal designing of energy-saving technologies of the induction heating of metals

    Science.gov (United States)

    Demidovich, V. B.

    2012-12-01

    Advanced energy-saving technologies of induction heating of metals are discussed. The importance of the joint simulation of electromagnetic and temperature fields on induction heating is demonstrated. The package of specialized programs for simulating not only induction heating devices, but also technologies that employ industrial heating has been developed. An intimate connection between optimal design and control of induction heaters is shown.

  9. Low Cost Variable Conductance Heat Pipe for Balloon Payload Project

    Data.gov (United States)

    National Aeronautics and Space Administration — While continuously increasing in complexity, the payloads of terrestrial high altitude balloons need a thermal management system to reject their waste heat and to...

  10. Optimization of Temperatures Heating Melt and Annealing Soft Magnetic Alloys

    Science.gov (United States)

    Tsepelev, Vladimir; Starodubtsev, Yuri

    2017-05-01

    Taking into account the concept of the quasi-chemical model of the liquid micro-non-uniform composition and the research made on the physical properties of the Fe-based melts being crystallized, the unique technology of the melt time-temperature treatment has been developed. Amorphous ribbons produced using this technology require optimal annealing temperatures to be specifically selected. Temperature dependences of the kinematic viscosity of a multicomponent Fe72.5Cu1Nb2Mo1.5Si14B9 melt have been studied. A critical temperature is detected above which the activation energy of viscous flow of the melt changes. Upon cooling the overheated melt, the temperature curves of the kinematic viscosity become linear within the given coordinates. In amorphous ribbon produced in the mode with overheating the melt above the critical temperature, the enthalpy of crystallization grows, the following heat treatment results in an increase in magnetic permeability.

  11. Greenhouse gas abatement cost curves of the residential heating market. A microeconomic approach

    Energy Technology Data Exchange (ETDEWEB)

    Dieckhoener, Caroline; Hecking, Harald

    2012-10-15

    In this paper, we develop a microeconomic approach to deduce greenhouse gas abatement cost curves of the residential heating sector. By accounting for household behavior, we find that welfare-based abatement costs are generally higher than pure technical equipment costs. Our results are based on a microsimulation of private households' investment decision for heating systems until 2030. The households' investment behavior in the simulation is derived from a discrete choice estimation which allows investigating the welfare costs of different abatement policies in terms of the compensating variation and the excess burden. We simulate greenhouse gas abatements and welfare costs of carbon taxes and subsidies on heating system investments until 2030 to deduce abatement curves. Given utility maximizing households, our results suggest a carbon tax to be the welfare efficient policy. Assuming behavioral misperceptions instead, a subsidy on investments might have lower marginal greenhouse gas abatement costs than a carbon tax.

  12. Minimizing investment cost for multi-period heat exchanger network retrofit by matching heat transfer areas with different strategies

    Institute of Scientific and Technical Information of China (English)

    Lixia Kang; Yongzhong Liu

    2015-01-01

    Multi-period heat exchanger network (HEN) retrofit is usually performed by targeting and matching heat trans-fer areas. In this paper, based on the reverse order matching method we proposed previously, three strategies of matching heat transfer areas are proposed to minimize the investment cost for the retrofit of HEN in multi-period, in which replacement of heat exchangers, addition of heat exchangers and addition of heat transfer areas are performed. We demonstrate the procedures through three scenarios, including maximum number of substituted heat exchangers after retrofit, minimum additional heat transfer areas in the retrofitted HEN, and minimum investment cost for retrofit. The strategies are extended to a single period HEN retrofit problem. The results of multi-period and single period HEN retrofit problems indicate the effectiveness of the strategies. More-over, these results are better than those reported in literature. The strategies are simple and easy to implement, which are of great benefit to large-scale HEN retrofit in practice.

  13. Optimization of Thermoelectric Components for Automobile Waste Heat Recovery Systems

    Science.gov (United States)

    Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.

    2015-10-01

    For a typical spark ignition engine approximately 40% of available thermal energy is lost as hot exhaust gas. To improve fuel economy, researchers are currently evaluating technology which exploits exhaust stream thermal power by use of thermoelectric generators (TEGs) that operate on the basis of the Seebeck effect. A 5% improvement in fuel economy, achieved by use of TEG output power, is a stated objective for light-duty trucks and personal automobiles. System modeling of thermoelectric (TE) components requires solution of coupled thermal and electric fluxes through the n and p-type semiconductor legs, given appropriate thermal boundary conditions at the junctions. Such applications have large thermal gradients along the semiconductor legs, and material properties are highly dependent on spatially varying temperature profiles. In this work, one-dimensional heat flux and temperature variations across thermoelectric legs were solved by using an iterative numerical approach to optimize both TE module and TEG designs. Design traits were investigated by assuming use of skutterudite as a thermoelectric material with potential for automotive applications in which exhaust gas and heat exchanger temperatures typically vary from 100°C to over 600°C. Dependence of leg efficiency, thermal fluxes and electric power generation on leg geometry, fill fractions, electric current, thermal boundary conditions, etc., were studied in detail. Optimum leg geometries were computed for a variety of automotive exhaust conditions.

  14. Experimental investigation on the thermal performance and optimization of heat sink with U-shape heat pipes

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Tian Shen [Faculty of Engineering and Technology, Multimedia University, 75450 Melaka (Malaysia); Hung, Yew Mun [School of Engineering, Monash University, 46150 Bandar Sunway (Malaysia)

    2010-11-15

    Experimental investigation is carried out to study the thermal performance of a heat sink with finned U-shape heat pipes which is a contemporary central processing unit (CPU) cooler compatible for a wide range of high-frequency microprocessors. The optimum range of operating heat load based on thermal resistance analysis of the heat sink is characterized. The convection heat transfer coefficient between the fins and the ambient air is estimated by using Bessel's modified equation in conjunction with the results obtained through the experimental investigation. The thermal optimization of the heat sink involves the determination of the optimized L-ratio (ratio of the evaporator section length to the condenser section length) of the U-shape heat pipe, by evaluating the minima of the thermal resistance function, in which case the empirical convection heat transfer coefficient is applied in the calculation. In conjunction with this, the optimal L-ratio of a U-shape heat pipe is found to be dependent on other geometrical parameters such as the heat pipe diameter and the fin spacing, which are of practical engineering importance in the optimum design of the heat sink. (author)

  15. Exergoeconomic optimization of an irreversible regenerated air refrigerator with constant-temperature heat reservoirs

    Directory of Open Access Journals (Sweden)

    Yi Zhang, Lingeng Chen, Guozhong Chai

    2015-01-01

    Full Text Available Based on the finite time exergoeconomic method, the performance analysis and optimization of an irreversible regenerated air refrigerator cycle are carried out by taking the profit rate as the optimization objective. The profit rate is defined as the difference between the revenue rate of output exergy and the cost rate of input exergy. The analytical expression for profit rate is derived, taking into account several irreversibilities, such as heat resistance, losses due to the pressure drop and the effects of non-isentropic expansion as well as compression. The influences of several parameters such as the temperature ratio of reservoirs, the efficiencies of both compressor and expander, the pressure recovery coefficient and so on are discussed by numerical examples. According to the simulation results, the double-maximum profit rate can be achieved when the pressure ratio and the distributions of heat conductance reach their optimal values respectively. By varying the price ratio, the relationship between the profit rate objective and other objectives can be established and the implementation of profit rate as objective can achieve higher COP compared to the cases using ecological function and cooling load as objectives.

  16. Optimasi Desain Heat Exchanger dengan Menggunakan Metode Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Rifnaldi Veriyawan

    2014-09-01

    Full Text Available Industri proses terutama perminyakan adalah salah satu industri membutuhkan energi panas dengan jumlah kapasitas besar. Dengan berjalan perkembangan teknologi dibutuhkannya proses perpindahan panas dalam jumlah besar. Tetapi dengan besarnya penukaran panas yang diberikan maka besar pula luas permukaan. Dibutuhkannya optimasi pada desain heat exchanger terutama shell-and-tube¬. Dalam tugas akhir ini, Algoritma particle swarm optimization (PSO digunakan untuk mengoptimasikan nilai koefesien perpindahan panas keseluruhan dengan mendapatkan nilai terbaik. Perumusan fungsi tujuan nilai perpindahan panas keseluruhan (U, dan luas permukaan (A yang digunakan untuk mencari nilai fungsi objektif pada PSO. Partikel dalam PSO menyatakan sebagai posisi atau solusi dari hasil optimasi didapatnya nilai perpindahan panas maksimal dengan luas permukaan dan pressure drop dibawah data desain atau datasheet. Partikel tersebut dalam pemodelan berupa rentang nilai minimal dan maksimal dari diameter luar diantara (do dan jumlah baffle (Nb. Dari hasil optimasi pada tiga HE didapatkan nilai U dan A secara berturut-turut; HE E-1111 472 W/m2C dan 289 m2 ;pada HE E-1107 174 W/m2C dan 265 m2 ; dan HE E-1102 618 W/m2C dan 574 m2. Nilai perpindahan panas keseluruhan yang telah dioptimasi sesuai dengan fungsi objektif dapat dikatakan HE shell-and-tube mencapai titik optimal.

  17. Costs of urban area retrofit to district heating and cooling systems: north-central cities

    Energy Technology Data Exchange (ETDEWEB)

    Santini, D J; Davis, A A; Marder, S M

    1978-03-01

    This study considers the major urbanized areas of six U.S. cities (Washington, D.C.; St. Louis; Cleveland; Milwaukee; Detroit; Chicago) to arrive at reasonably accurate estimates of costs required to retrofit them with district heating and cooling systems. Only costs associated with heating and hot water are addressed here. Demand estimates and energy-supply analyses are made, and component capital costs are estimated to arrive at annualized system costs. Finally, a comparison of alternative energy-delivery options is made, and estimates of scarce-fuel savings are derived. 39 refs., 12 figs., 14 tables.

  18. Optimization of nanofluid-cooled microchannel heat sink

    Directory of Open Access Journals (Sweden)

    Adham Ahmed Mohammed

    2016-01-01

    Full Text Available The optimization of a nanofluid-cooled rectangular microchannel heat sink is reported. Two nanofluids with volume fraction of 1 %, 3 %, 5 %, 7 % and 9 % are employed to enhance the overall performance of the system. An optimization scheme is applied consisting of a systematic thermal resistance model as an analysis method and the elitist non-dominated sorting genetic algorithm (NSGA-II. The optimized results showed that the increase in the particles volume fraction results in a decrease in the total thermal resistance and an increase in the pumping power. For volume fractions of 1 %, 3 %, 5 %, 7 % and 9 %, the thermal resistances were 0.072, 0.07151, 0.07075, 0.07024 and 0.070 [oK W-1] for the SiC-H2O while, they were 0.0705, 0.0697, 0.0694, 0.0692 and 0.069 [oK W-1] for the TiO2-H2O. The associated pumping power were 0.633, 0.638, 0.704, 0.757 and 0.807 [W] for the SiC-H2O while they were 0.645, 0.675, 0.724, 0.755 and 0.798 [W] for the TiO2-H2O. In addition, for the same operating conditions, the nanofluid-cooled system outperformed the water-cooled system in terms of the total thermal resistance (0.069 and 0.11 for nanofluid-cooled and water-cooled systems, respectively. Based on the results observed in this study, nanofluids should be considered as the future coolant for electronic devices cooling systems.

  19. Optimal Privacy-Cost Trade-off in Demand-Side Management with Storage

    OpenAIRE

    Tan, Onur; Gündüz, Deniz; Gómez-Vilardebó, Jesús

    2015-01-01

    Demand-side energy storage management is studied from a joint privacy-energy cost optimization perspective. Assuming that the user's power demand profile as well as the electricity prices are known non-causally, the optimal energy management (EM) policy that jointly increases the privacy of the user and reduces his energy cost is characterized. The backward water-filling interpretation is provided for the optimal EM policy. While the energy cost is reduced by requesting more energy when the p...

  20. Cost optimization of biofuel production – The impact of scale, integration, transport and supply chain configurations

    NARCIS (Netherlands)

    de Jong, S.A.|info:eu-repo/dai/nl/41200836X; Hoefnagels, E.T.A.|info:eu-repo/dai/nl/313935998; Wetterlund, Elisabeth; Pettersson, Karin; Faaij, André; Junginger, H.M.|info:eu-repo/dai/nl/202130703

    2017-01-01

    This study uses a geographically-explicit cost optimization model to analyze the impact of and interrelation between four cost reduction strategies for biofuel production: economies of scale, intermodal transport, integration with existing industries, and distributed supply chain configurations

  1. Potential escalation of heat-related working costs with climate and socioeconomic changes in China

    National Research Council Canada - National Science Library

    Yan Zhao; Benjamin Sultan; Robert Vautard; Pascale Braconnot; Huijun J. Wang; Agnes Ducharne

    2016-01-01

    .... In mainland China, high-temperature subsidies (HTSs) are allocated to employees for each working day in extremely hot environments, but the potential heat-related increase in labor cost has not been evaluated so far...

  2. An attempt of reduction of optimization costs of complex industrial processes

    Science.gov (United States)

    Sztangret, Łukasz; Kusiak, Jan

    2017-09-01

    Reduction of computational costs of optimization of real industrial processes is crucial, because the models of these processes are often complex and demand time consuming numerical computations. Iterative optimization procedures have to run the simulations many times and therefore the computational costs of the optimization may be unacceptable high. This is why a new optimization methods and strategies which need less simulation runs are searched. The paper is focused on the problem of reduction of computational costs of optimization procedure. The main goal is the presentation of developed by the Authors new, efficient Approximation Based Optimization (ABO) and Modified Approximation Based Optimization (MABO) methods which allow finding the global minimum in smaller number of objective function calls. Detailed algorithm of the MABO method as well as the results of tests using several benchmark functions are presented. The efficiency of MABO method was compared with heuristic methods and the results show that MABO method reduces the computational costs and improve the optimization accuracy.

  3. Modification of the LCOE model to estimate a cost of heat and power generation for Russia

    OpenAIRE

    Bratanova, Alexandra; Robinson, Jacqueline; Wagner, Liam

    2015-01-01

    The Russian heat sector faces crucial problems including underinvestment, below cost pricing, generation capacity and infrastructure depletion. While the Russian electricity sector has gradually progressed through liberalization, the heat sector is still waiting for similar reforms to occur. The modernisation of the sector requires analysis of energy generation costs to suggest feasible technological solutions and secure an increase of investment in the industry. This study presents a modific...

  4. Robust Optimization for Time-Cost Tradeoff Problem in Construction Projects

    OpenAIRE

    Ming Li; Guangdong Wu

    2014-01-01

    Construction projects are generally subject to uncertainty, which influences the realization of time-cost tradeoff in project management. This paper addresses a time-cost tradeoff problem under uncertainty, in which activities in projects can be executed in different construction modes corresponding to specified time and cost with interval uncertainty. Based on multiobjective robust optimization method, a robust optimization model for time-cost tradeoff problem is developed. In order to illus...

  5. Cost reduction in the cold: heat generated by terrestrial locomotion partly substitutes for thermoregulation costs in Knot Calidris canutus

    NARCIS (Netherlands)

    Bruinzeel, L.W.; Piersma, T.

    1998-01-01

    To test whether heat generated during locomotion substitutes for the thermoregulation cost, oxygen consumption of four post-absorptive temperate-wintering Knot Calidris canutus was measured at air temperatures of 25 degrees C (thermoneutral) and 10 degrees C (c. 10 degrees below the lower critical

  6. Cost reduction in the cold : heat generated by terrestrial locomotion partly substitutes for thermoregulation costs in Knot Calidris canutus

    NARCIS (Netherlands)

    Bruinzeel, Leo W.; Piersma, T

    To test whether heat generated during locomotion substitutes for the thermoregulation cost, oxygen consumption of four post-absorptive temperate-wintering Knot Calidris canutus was measured at air temperatures of 25 degrees C (thermoneutral) and 10 degrees C (c. 10 degrees below the lower critical

  7. OSP(TM): Optimal Steel Making Process (Low cost steelmaking plus ecological benefits)

    Energy Technology Data Exchange (ETDEWEB)

    Wunsche, R. [EMPCO Ltd., Whitby, ON (Canada)

    2001-07-01

    The Optimal Steelmaking Process (OSP)(TM) utilizes a non-electric multi-oxy-fuel powered metallurgical furnace. It is proposed that this furnace can replace the electric arc furnace for scrap recycling. The process OSP(TM) uses a novel scrap preheating apparatus, called ROTOBIN(TM) prior to feeding the scrap into the metallurgical furnace. ROTOBIN(TM) makes use of heat recovered from the hot waste gases emitted from the furnace exhaust. While doing so, it simultaneously reduces the contaminants from the scrap. Energy for the process is provided by multi-oxy fuel systems UNILANCE(TM) or COMBILANCE(TM). Benefits of the system in terms of reduced operating conversion costs, increased productivity, improved energy efficiency, improved safety and overall working environment, and reduced air and solid pollutants generation are described. 3 tabs.

  8. Experimental Analysis of a Heat Cost Allocation Method for Apartment Buildings

    Directory of Open Access Journals (Sweden)

    Fabio Saba

    2017-03-01

    Full Text Available The correct estimate of individual thermal energy consumptions, and consequently, a fair heat cost allocation among the residents of apartment buildings with centralized heating systems, represents an important driving force towards energy saving, energy efficiency and the reduction of pollutant emissions. Nowadays, in those contexts where direct heat meters cannot be used because of the layout of the hot water distribution system, electronic Heat Cost Allocators (HCAs have the highest market share for the assessment of individual thermal energy consumptions. The uncertainty associated with the parameterization of heat cost allocation devices and the installation effects arising in real applications can negatively affect the accuracy of these devices, as far as the estimation of the individual fractions of thermal energy consumption is concerned. This work deals with the experimental analysis of a novel heat cost allocation method for apartment buildings and its comparison with conventional HCAs. The method allows the indirect estimation of the thermal energy exchanged by water radiators without the need for surface temperature measurements, reducing some of the drawbacks associated with the on-site installation. The experimental analysis was carried out in a full-scale central heating system test facility available at the Italian National Metrology Institute (INRIM and characterized by SI-traceable direct heat meters installed on each water radiator.

  9. Color tunable low cost transparent heat reflector using copper and titanium oxide for energy saving application

    OpenAIRE

    Goutam Kumar Dalapati; Saeid Masudy-Panah; Sing Teng Chua; Mohit Sharma; Ten It Wong; Hui Ru Tan; Dongzhi Chi

    2016-01-01

    Multilayer coating structure comprising a copper (Cu) layer sandwiched between titanium dioxide (TiO2) were demonstrated as a transparent heat reflecting (THR) coating on glass for energy-saving window application. The main highlight is the utilization of Cu, a low-cost material, in-lieu of silver which is widely used in current commercial heat reflecting coating on glass. Color tunable transparent heat reflecting coating was realized through the design of multilayer structure and process opt...

  10. Optimal guaranteed cost control for fuzzy descriptor systems with time-varying delay

    Institute of Scientific and Technical Information of China (English)

    Tian Weihua; Zhang Huaguang

    2008-01-01

    Based on the delay-independent rule, the problem of optimal guaranteed cost control for a class of Takagi-Sugeno (T-S) fuzzy descriptor systems with time-varying delay is studied. A linear quadratic cost function is considered as the performance index of the closed-loop system. Sufficient conditions for the existence of guaranteed cost controllers via state feedback are given in terms of linear matrix inequalities (LMIs), and the design of an optimal guaranteed cost controller can be reduced to a convex optimization problem. It is shown that the designed controller not only guarantees the asymptotic stability of the closed-loop fuzzy descriptor delay system, but also provides an optimized upper bound of the guaranteed cost. At last, a numerical example is given to illustrate the effectiveness of the proposed method and the perfect performance of the optimal guaranteed cost controller.

  11. Optimalization of logistic costs by the controlling approach

    Directory of Open Access Journals (Sweden)

    Katarína Teplická

    2007-10-01

    Full Text Available Article deals with logistic cost problems, their following, reporting and evaluation in the firm. It gives basic information about possible access of the effective decreasing of the logistic cost by the way of controlling access, or evaluation of Balance Score Card. It indicates short algorithm of logistic costs reporting by the way of controlling.

  12. Simulator for Optimization of Software Project Cost and Schedule

    Directory of Open Access Journals (Sweden)

    P. K. Suri

    2008-01-01

    Full Text Available Each phase of the software design consumes some resources and hence has cost associated with it. In most of the cases cost will vary to some extent with the amount of time consumed by the design of each phase .The total cost of project, which is aggregate of the activities costs will also depends upon the project duration, can be cut down to some extent. The aim is always to strike a balance between the cost and time and to obtain an optimum software project schedule. An optimum minimum cost project schedule implies lowest possible cost and the associated time for the software project management. In this research an attempt has been made to solve the cost and schedule problem of software project using PERT network showing the details of the activities to be carried out for a software project development/management with the help of crashing, reducing software project duration at a minimum cost by locating a minimal cut in the duration of an activity of the original project design network. This minimal cut is then utilized to identify the project phases which should experience a duration modification in order to achieve the total software duration reduction. Crashing PERT networks can save a significant amount of money in crashing and overrun costs of a company. Even if there are no direct costs in the form of penalties for late completion of projects, there is likely to be intangible costs because of reputation damage.

  13. Optimalization of logistic costs by the controlling approach

    OpenAIRE

    Katarína Teplická

    2007-01-01

    Article deals with logistic cost problems, their following, reporting and evaluation in the firm. It gives basic information about possible access of the effective decreasing of the logistic cost by the way of controlling access, or evaluation of Balance Score Card. It indicates short algorithm of logistic costs reporting by the way of controlling.

  14. Optimal configuration for a finite low-temperature source refrigerator cycle with heat transfer law

    Directory of Open Access Journals (Sweden)

    Jun Li, Lingen Chen, Yanlin Ge, Fengrui Sun

    2016-01-01

    Full Text Available The optimal configuration of a refrigeration cycle operating between a finite low-temperature source and an infinite high-temperature sink are derived by using finite time thermodynamics based on a complex heat transfer law, including Newtonian heat transfer law, linear phenomenological heat transfer law, radiative heat transfer law, Dulong-Petit heat transfer law, generalized convective heat transfer law and generalized radiative heat transfer law. In the refrigeration cycle model the only irreversibility of finite rate heat transfer is considered. The optimal relation between cooling load and coefficient of performance (COP of the refrigeration cycle is also derived by using an equivalent temperature of low-temperature source. The obtained results include those with various heat transfer laws and infinite low-temperature source, and can provide some theoretical guidelines for the designs of practical refrigerators.

  15. Optimization analysis of high temperature heat pump coupling to desiccant wheel air conditioning system

    DEFF Research Database (Denmark)

    Sheng, Ying; Zhang, Yufeng; Fang, Lei

    2014-01-01

    The high temperature heat pump and desiccant wheel (HTHP&DW) system can make full use of heat released from the condenser of heat pump for DW regeneration without additional heat. In this study, DW operation in the HTHP&DW system was investigated experimentally, and the optimization analysis....... Compared to the isosteric heat, heat accumulation in the desiccant and matrix material and heat leakage from regeneration side to process side have greater influence on the adiabatic effectiveness. Higher regeneration temperature leads to lower adiabatic effectiveness that increases more cooling load...

  16. Analytical study on coordinative optimization of convection in tubes with variable heat flux

    Institute of Scientific and Technical Information of China (English)

    YUAN Zhongxian; ZHANG Jianguo; JIANG Mingjian

    2004-01-01

    The laminar heat transfer in the thermal entrance region in round tubes, which has a variable surface heat flux boundary condition, is analytically studied. The results show that the heat transfer coefficient is closely related to the wall temperature gradient along the tube axis. The greater the gradient, the higher the heat transfer rate. Furthermore, the coordination of the velocity and the temperature gradient fields is also analysed under different surface heat fluxes. The validity of the field coordination principle is verified by checking the correlation of heat transfer coefficient and the coordination degree. The results also demonstrate that optimizing the thermal boundary condition is a way to enhance heat transfer.

  17. A heat & mass integration approach to reduce capital and operating costs of a distillation configuration

    Energy Technology Data Exchange (ETDEWEB)

    Madenoor Ramapriya, Gautham [Purdue University; Jiang, Zheyu [Purdue University; Tawarmalani, Mohit [Purdue University; Agrawal, Rakesh [Purdue University

    2015-11-11

    We propose a general method to consolidate distillation columns of a distillation configuration using heat and mass integration. The proposed method encompasses all heat and mass integrations known till date, and includes many more. Each heat and mass integration eliminates a distillation column, a condenser, a reboiler and the heat duty associated with a reboiler. Thus, heat and mass integration can potentially offer significant capital and operating cost benefits. In this talk, we will study the various possible heat and mass integrations in detail, and demonstrate their benefits using case studies. This work will lay out a framework to synthesize an entire new class of useful configurations based on heat and mass integration of distillation columns.

  18. Using Minitab-Box Benken Software to Optimize the Induction Heating Process

    Directory of Open Access Journals (Sweden)

    LEUCA Teodor

    2014-05-01

    Full Text Available This paper presents aspects on finding some optimal dependence between the inductor input parameters (frequency, air gap and current density and its output parameters (spacing, power density, heating time. It also shows the results of coupling the numerical modeling of the inductive heating process, using Flux 2D, with a numerical model of optimization, using Minitab software.

  19. Optimization and Performance Study of Select Heating Ventilation and Air Conditioning Technologies for Commercial Buildings

    Science.gov (United States)

    Kamal, Rajeev

    part load operation. The study highlighted the need for optimum system sizing for GEHP/HVAC systems to meet the building load to obtain better performance in buildings. The second part of this study focusses on using chilled water or ice as thermal energy storage for shifting the air conditioning load from peak to off-peak in a commercial building. Thermal energy storage can play a very important role in providing demand-side management for diversifying the utility demand from buildings. Model of a large commercial office building is developed with thermal storage for cooling for peak power shifting. Three variations of the model were developed and analyzed for their performance with 1) ice storage, 2) chilled water storage with mixed storage tank and 3) chilled water storage with stratified tank, using EnergyPlus 8.5 software developed by the US Department of Energy. Operation strategy with tactical control to incorporate peak power schedule was developed using energy management system (EMS). The modeled HVAC system was optimized for minimum cost with the optimal storage capacity and chiller size using JEPlus. Based on the simulation, an optimal storage capacity of 40-45 GJ was estimated for the large office building model along with 40% smaller chiller capacity resulting in higher chiller part-load performance. Additionally, the auxiliary system like pump and condenser were also optimized to smaller capacities and thus resulting in less power demand during operation. The overall annual saving potential was found in the range of 7-10% for cooling electricity use resulting in 10-17% reduction in costs to the consumer. A possible annual peak shifting of 25-78% was found from the simulation results after comparing with the reference models. Adopting TES in commercial buildings and achieving 25% peak shifting could result in a reduction in peak summer demand of 1398 MW in Tampa.

  20. Potential escalation of heat-related working costs with climate and socioeconomic changes in China

    OpenAIRE

    Yan ZHAO; Sultan, Benjamin; Vautard, Robert; Braconnot, Pascale; Wang, Huijun J.; Ducharne, Agnes

    2016-01-01

    Global climate change will increase the frequency of hot temperatures, impairing health and productivity for millions of working people and raising labor costs. In mainland China, high-temperature subsidies (HTSs) are allocated to employees for each working day in extremely hot environments, but the potential heat-related increase in labor cost has not been evaluated so far. Here, we estimate the potential HTS cost in current and future climates under different scenarios of socioeconomic deve...

  1. Exergetic efficiency optimization for an irreversible heat pump working on reversed Brayton cycle

    Indian Academy of Sciences (India)

    Yuehong Bi; Lingen Chen; Fengrui Sun

    2010-03-01

    This paper deals with the performance analysis and optimization for irreversible heat pumps working on reversed Brayton cycle with constant-temperature heat reservoirs by taking exergetic efficiency as the optimization objective combining exergy concept with finite-time thermodynamics (FTT). Exergetic efficiency is defined as the ratio of rate of exergy output to rate of exergy input of the system. The irreversibilities considered in the system include heat resistance losses in the hot- and cold-side heat exchangers and non-isentropic losses in the compression and expansion processes. The analytical formulas of the heating load, coefficient of performance (COP) and exergetic efficiency for the heat pumps are derived. The results are compared with those obtained for the traditional heating load and coefficient of performance objectives. The influences of the pressure ratio of the compressor, the allocation of heat exchanger inventory, the temperature ratio of two reservoirs, the effectiveness of the hot- and cold-side heat exchangers and regenerator, the efficiencies of the compressor and expander, the ratio of hot-side heat reservoir temperature to ambient temperature, the total heat exchanger inventory, and the heat capacity rate of the working fluid on the exergetic efficiency of the heat pumps are analysed by numerical calculations. The results show that the exergetic efficiency optimization is an important and effective criterion for the evaluation of an irreversible heat pump working on reversed Brayton cycle.

  2. Entransy and exergy analyses for optimizations of heat-work conversion with carnot cycle

    Science.gov (United States)

    Han, Chul Ho; Kim, Kyoung Hoon

    2016-06-01

    The concept of entransy has been newly proposed in terms of the analogy between heat and electrical conduction and could be useful in analyzing and optimizing the heat-work conversion systems. This work presents comparative analyses of entransy and exergy for optimizations of heat-work conversion. The work production and heat transfer processes in Carnot cycle system are investigated with the formulations of exergy destruction, entransy loss, work entransy, entransy dissipation, and efficiencies for both cases of dumping and non-dumping of used source fluid. The effects of source and condensation temperatures on the system performance are systematically investigated for optimal condition of producing maximum work or work entransy.

  3. Cost Estimates Of Concentrated Photovoltaic Heat Sink Production

    Science.gov (United States)

    2016-06-01

    also researched through analyzing electricity rate data, CPV market research , and a firsthand account with an industry representative from a... capital costs and intermittency (DASN, 2012). While the price per kWh of solar is falling as the solar market continues to mature, solar installation...grow (evolve India). Retrieved from http://evolveindia.in/blog/2015/10/24/solar-tracker- market - expected-to-grow/ NREL. (2016). Best research cell

  4. Optimal design of Stirling heat engine using an advanced optimization algorithm

    Indian Academy of Sciences (India)

    R V RAO; K C MORE; J TALER; P OCION

    2016-11-01

    The Stirling engine presents an excellent theoretical output equivalent to the output of Carnot engine and it is less pollutant and requires little maintenance. In this paper, Stirling heat engine is considered for optimization with multiple criteria. A recently developed advanced optimization algorithm namely ‘‘teaching–learning-based optimization (TLBO) algorithm’’ is used for maximization of output power, minimization ofpressure losses and maximization of the thermal efficiency of the entire solar Stirling system. The comparisons of the proposed algorithm are made with those obtained by using the decision-making methods like linear programming technique for multi-dimensional analysis of preference (LINMAP), technique for order of preference by similarity to ideal solution (TOPSIS) and fuzzy Bellman–Zadeh method that have used the Pareto frontier gained through non-dominated sorting genetic algorithm-II (NSGA-II). The comparisons were also made with those obtained by the experimental results. It is found that the TLBO algorithm has produced comparatively better results than those given by the decision-making methods and the experimental results presented by the previous researchers.

  5. Design and optimization of a non-TEMA type tubular recuperative heat exchanger used in a regenerative gas turbine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Sayyaadi, Hoseyn; Aminian, Hamid Reza [Faculty of Mechanical Engineering-Energy Division, K.N. Toosi University of Technology, P.O. Box: 19395-1999, No. 15-19, Pardis Str., Mollasadra Ave., Vanak Sq., Tehran 1999 143344 (Iran)

    2010-04-15

    A special non-TEMA type tubular recuperative heat exchanger used as a regenerator of a gas turbine cycle is considered for multi-criteria optimization. It is assumed that the recuperator is designed for an existing gas turbine cycle to be retrofitted. Three scenarios for optimization of the proposed system have been considered. In one scenario, the objective is minimizing the cost of recuperator; while in another scenario maximizing the cycle exergetic efficiency is considered. In third scenario, both objectives are optimized simultaneously in a multi-objective optimization approach. Geometric specification of the recuperator including tubes length, tubes outside/inside diameters, tube pitch in the tube bundle, inside shell diameter, outer and inner tube limits of the tube bundle and the total number of disc and doughnut baffles are considered as decision variables. Combination of these objectives and decision variables with suitable engineering and physical constraints (including NO{sub x} and CO emission limitations) makes a set of MINLP optimization problem. Optimization programming in MATLAB is performed using one of the most powerful and robust multi-objective optimization algorithms namely NSGA-II. This approach which is based on the Genetic Algorithm is applied to find a set of Pareto optimal solutions. Pareto optimal frontier is obtained and a final optimal solution is selected in a decision-making process. It is shown that the multi-objective optimization scenario can be considered as a generalized optimization approach in which balances between economical viewpoints of both heat exchanger manufacturer and end user of recuperator. (author)

  6. Coupled heating/forming optimization of knitted reinforced composites

    Science.gov (United States)

    Pancrace, Johann

    The feasibility of knitted fabric reinforcement for highly flexible composites has been investigated for the thermoforming process. The composite sheets were made through compression molding before being shaped. We used thermoplastic elastomers as matrices: Thermoplastic Elastomers and Thermoplastic Olefins. The knit reinforcement was provided by jersey knitted fabrics of polyester fibers. We first introduced the fundamentals involved in the study. The manufacturing is presented through compression molding and thermoforming. The latter is a two-step process: IR heating and plug/pressure assisted deformations. For the IR heating phase, several material properties have been characterized: the emissivity of matrices, absorption, reflection and transmission of radiations in the composite structure have been studied. We particularly paid attention to the reflection on the composite surfaces. The non-reflected or useful radiations leading to the heating are quantified and simulated for three emitter-composite configurations. It has been found that the emitter temperatures and the angle of incidence have significant roles in the IR heating phase. Thermal properties such as calorific capacity and thermal conductivity of the composites were also presented. Thermograms were carried out with an IR camera. Equipment and Thermogram acquisitions were both presented. Optimization of emitters was performed for a three emitter system. The objective function method has been illustrated. Regarding mechanical purposes, the characterizations of the matrices, reinforcements and flexible composites have been carried out. The studied loadings were uniaxial traction, pure shear and biaxial inflation. For the uniaxial extension, both the reinforcement and the composite were found highly anisotropic regarding the orientation of the loading toward the coursewise of the fabric. The resulting strains and stresses to rupture are also found anisotropic. However, for pure shear loading we observed

  7. Heat transfer optimization of SCO2 porous flow based on Brinkman model

    Directory of Open Access Journals (Sweden)

    Lin David T.W.

    2016-01-01

    Full Text Available The purpose of this study is to obtain the optimal operating condition in order to find the maximum supercritical CO2 heat extraction in the enhanced geothermal system (EGS. In this study, the heat transfer model conjugated with the Brinkman model is used to evaluate the thermal behavior in the reservoir of the EGS. This numerical model is validated by experiment. Optimization is processed based on the Nelder-Mead approach. The optimal operating conditions are proposed with different pressure, porosity. This study will build the optimal platform of heat source of geothermal power plant.

  8. Sizing Combined Heat and Power Units and Domestic Building Energy Cost Optimisation

    Directory of Open Access Journals (Sweden)

    Dongmin Yu

    2017-06-01

    Full Text Available Many combined heat and power (CHP units have been installed in domestic buildings to increase energy efficiency and reduce energy costs. However, inappropriate sizing of a CHP may actually increase energy costs and reduce energy efficiency. Moreover, the high manufacturing cost of batteries makes batteries less affordable. Therefore, this paper will attempt to size the capacity of CHP and optimise daily energy costs for a domestic building with only CHP installed. In this paper, electricity and heat loads are firstly used as sizing criteria in finding the best capacities of different types of CHP with the help of the maximum rectangle (MR method. Subsequently, the genetic algorithm (GA will be used to optimise the daily energy costs of the different cases. Then, heat and electricity loads are jointly considered for sizing different types of CHP and for optimising the daily energy costs through the GA method. The optimisation results show that the GA sizing method gives a higher average daily energy cost saving, which is 13% reduction compared to a building without installing CHP. However, to achieve this, there will be about 3% energy efficiency reduction and 7% input power to rated power ratio reduction compared to using the MR method and heat demand in sizing CHP.

  9. On the question of heat engine cycles optimization

    Directory of Open Access Journals (Sweden)

    Костянтин Ігорович Ткаченко

    2015-10-01

    Full Text Available It is known that the efficiency of heat engines nowadays isn’t more than 50-60% for prototypes and maximum possible efficiency of a heat engine is considered Carnot cycle efficiency Thus, at least 40% of the disposable amount of heat is lost in the surrounding medium, unless the waste gases heat is utilized somehow. General idea of heat engines cycles is the transfer of energy from the heater (both external and internal to a working fluid, obtaining mechanical work from expanding of the working fluid, and returning the working fluid to the initial state by compression and excess heat discharge into a cooler. In this paper the combination of a heat engine operating according to the standard Edwards cycle and consisting of isochor, adiabat and isotherm, and the heat pump, using the reverse Carnot cycle is investigated. The heat pump partially picks out the heat of the working fluid at its isothermal compression, and returns it to the equivalent working fluid or regenerator cap, at the beginning of isochoric heating. The efficiency coefficient of the heat pump, and thus the work to putting it into action is calculated by proper equations at the constant temperature of the low-potential heat source (working fluid and variable temperature of the heated equivalent of the working fluid or the regenerator cap. Taking as an example selected quantitative parameters of the Edwards cycle it has been proved that the use of the heat pump increases the effective efficiency of combined cycle as compared to the basic one. In addition, it has been shown that the dependence of the efficiency on the degree of heat return is not monotonic and has a maximum

  10. Process Cost Modeling for Multi-Disciplinary Design Optimization

    Science.gov (United States)

    Bao, Han P.; Freeman, William (Technical Monitor)

    2002-01-01

    For early design concepts, the conventional approach to cost is normally some kind of parametric weight-based cost model. There is now ample evidence that this approach can be misleading and inaccurate. By the nature of its development, a parametric cost model requires historical data and is valid only if the new design is analogous to those for which the model was derived. Advanced aerospace vehicles have no historical production data and are nowhere near the vehicles of the past. Using an existing weight-based cost model would only lead to errors and distortions of the true production cost. This report outlines the development of a process-based cost model in which the physical elements of the vehicle are costed according to a first-order dynamics model. This theoretical cost model, first advocated by early work at MIT, has been expanded to cover the basic structures of an advanced aerospace vehicle. Elemental costs based on the geometry of the design can be summed up to provide an overall estimation of the total production cost for a design configuration. This capability to directly link any design configuration to realistic cost estimation is a key requirement for high payoff MDO problems. Another important consideration in this report is the handling of part or product complexity. Here the concept of cost modulus is introduced to take into account variability due to different materials, sizes, shapes, precision of fabrication, and equipment requirements. The most important implication of the development of the proposed process-based cost model is that different design configurations can now be quickly related to their cost estimates in a seamless calculation process easily implemented on any spreadsheet tool. In successive sections, the report addresses the issues of cost modeling as follows. First, an introduction is presented to provide the background for the research work. Next, a quick review of cost estimation techniques is made with the intention to

  11. Optimized Heat Pipe Backup Cooling System Tested with a Stirling Convertor

    Science.gov (United States)

    Schwendeman, Carl L.; Tarau, Calin; Schifer, Nicholas A.; Anderson, William G.; Garner, Scott

    2016-01-01

    In a Stirling Radioisotope Power System (RPS), heat must be continuously removed from the General Purpose Heat Source (GPHS) modules to maintain the modules and surrounding insulation at acceptable temperatures. The Stirling convertor normally provides this cooling. If the Stirling convertor stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS at the cost of an early termination of the mission. An alkali-metal variable conductance heat pipe (VCHP) can be used to passively allow multiple stops and restarts of the Stirling convertor by bypassing the heat during stops. In a previous NASA Small Business Innovation Research (SBIR) Program, Advanced Cooling Technologies, Inc. (ACT) developed a series of sodium VCHPs as backup cooling systems for the Stirling RPS. In 2012, one of these VCHPs was successfully tested at NASA Glenn Research Center with a Stirling convertor as an Advanced Stirling Radioisotope Generator (ASRG) backup cooling system. The prototype; however, was not optimized and did not reflect the final heat rejection path. ACT through further funding has developed a semioptimized prototype with the finalized heat path for testing at Glenn with a Stirling convertor. The semioptimized system features a two-phase radiator and is significantly smaller and lighter than the prior prototype to reflect a higher level of flight readiness. The VCHP is designed to activate and remove heat from the GPHS during stoppage with a small temperature increase from the nominal vapor temperature. This small temperature increase from nominal is low enough to avoid risking standard ASRG operation and spoiling of the multilayer insulation (MLI). The VCHP passively allows the Stirling convertor to be turned off multiple times during a mission with potentially unlimited off durations. Having the ability to turn the Stirling off allows for the Stirling to be reset and reduces vibrations on the platform during sensitive measurements or

  12. 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.

  13. Integrated energy, economic, and environmental assessment for the optimal solar absorption cooling and heating system

    Science.gov (United States)

    Hang, Yin

    Buildings in the United States are responsible for 41% of the primary energy use and 30% of carbon dioxide emissions. Due to mounting concerns about climate change and resource depletion, meeting building heating and cooling demand with renewable energy has attracted increasing attention in the energy system design of green buildings. One of these approaches, the solar absorption cooling and heating (SACH) technology can be a key solution to addressing the energy and environmental challenges. SACH system is an integration of solar thermal heating system and solar thermal driven absorption cooling system. So far, SACH systems still remain at the demonstration and testing stage due to not only its high cost but also complicated system characteristics. This research aims to develop a methodology to evaluate the life cycle energy, economic and environmental performance of SACH systems by high-fidelity simulations validated by experimental data. The developed methodology can be used to assist the system design. In order to achieve this goal, the study includes four objectives as follows: * Objective 1: Develop the evaluation model for the SACH system. The model includes three aspects: energy, economy, and environment from a life cycle point of view. * Objective 2: Validate the energy system model by solar experiments performance data. * Objective 3: Develop a fast and effective multi-objective optimization methodology to find the optimal system configuration which achieves the maximum system benefits on energy, economy and environment. Statistic techniques are explored to reveal the relations between the system key parameters and the three evaluation targets. The Pareto front is generated by solving this multi-objective optimization problem. * Objective 4: Apply the developed assessment methodology to different building types and locations. Furthermore, this study considered the influence of the input uncertainties on the overall system performance. The sensitivity

  14. Geometric optimization of bodies submitted to an intense heat flux using bifurcated channel nets

    OpenAIRE

    Bolzan, Claus de Rosso; Santos, Elizaldo Domingues dos; Isoldi, Liercio André; Rocha, Luiz Alberto Oliveira

    2009-01-01

    The present work studies the geometric optimization of a body submitted to intense heat flux. The body to be optimized is refrigerated by a ducts system whose circulating fluid will remove the heat. The optimization method is denominated "Constructal Design" and it is based on Constructal theory", which is a new theory that guides the engineers in the discovery of new and highly efficient architectures for the drainage of fluids, mass, energy, and " anything that moves ". The maximum temperat...

  15. Sequential optimization of matrix chain multiplication relative to different cost functions

    KAUST Repository

    Chikalov, Igor

    2011-01-01

    In this paper, we present a methodology to optimize matrix chain multiplication sequentially relative to different cost functions such as total number of scalar multiplications, communication overhead in a multiprocessor environment, etc. For n matrices our optimization procedure requires O(n 3) arithmetic operations per one cost function. This work is done in the framework of a dynamic programming extension that allows sequential optimization relative to different criteria. © 2011 Springer-Verlag Berlin Heidelberg.

  16. OPTIMIZATION OF HEATING OF GEAR WHEEL USING NUMERICAL MODELING

    Directory of Open Access Journals (Sweden)

    Sona Benesova

    2013-05-01

    Full Text Available Successful heat treating and carburizing of gear wheels for wind turbine gear boxes requires that plastic deformation in the wheel is minimized. Numerical modeling using the DEFORM software was aimed at exploring the effects of the base, on which the gear wheel rests during heating, on the heating process. Homogeneous heating was assumed. It was found that the base heats up more quickly than the workpiece. It is the consequence of the base's shape and volume. As a result, the base expands and slides against the wheel, predominantly at the first heating stage. Later on, it prevents the gear wheel from expanding, causing plastic deformation in the wheel. The findings were used for designing new heating schedules to minimize these undesirable interactions and to reduce the plastic deformation to a negligible magnitude. In addition, this paper presents an example of a practical use of numerical modeling in the DEFORM software.

  17. OPTIMIZATION OF HEATING OF GEAR WHEEL USING NUMERICAL MODELING

    Directory of Open Access Journals (Sweden)

    Soňa Benešová

    2013-09-01

    Full Text Available Successful heat treating and carburizing of gear wheels for wind turbine gear boxes requires that plastic deformation in the wheel is minimized. Numerical modeling using the DEFORM software was aimed at exploring the effects of the base, on which the gear wheel rests during heating, on the heating process. Homogeneous heating was assumed. It was found that the base heats up more quickly than the workpiece. It is the consequence of the base's shape and volume. As a result, the base expands and slides against the wheel, predominantly at the first heating stage. Later on, it prevents the gear wheel from expanding, causing plastic deformation in the wheel. The findings were used for designing new heating schedules to minimize these undesirable interactions and to reduce the plastic deformation to a negligible magnitude. In addition, this paper presents an example of a practical use of numerical modeling in the DEFORM software.

  18. Multiple tube structure for heating uniformity and efficiency optimization of microwave ovens

    Science.gov (United States)

    Zhou, Rong; Yang, Xiaoqing; Sun, Di; Jia, Guozhu

    2015-02-01

    Microwave heating is widely applied to microwave assisted chemical reactions in modified domestic microwave ovens, however, the potential issues (non-uniformity and low heating efficiency) still exist during the heating process. In this paper, a new heating model of multiple tube structure is proposed and the relevant simulations and experiments of heating water were performed based on the computational platform COMSOL Multi-physics software in order to achieve the better temperature uniformity and heating efficiency. Besides, the influence of the instability of microwave ovens on the heating performances of the optimal heating models was analyzed. The simulation results show that the heating uniformity and efficiency of water in optimal six tube structure increased by 7.1% and 68.5% (30 mL), 9.2% and 61% (60 mL) respectively compared with the optimal single tube structure. Moreover, the heating performances of the optimal heating models do not change obviously, while the working frequency and power change slightly. The simulation results are in good agreement with the experiment data.

  19. Optimisation of single-tube heating systems with distribution of heating cost; Optimierung von Einrohrheizungsanlagen mit Heizkostenverteilung

    Energy Technology Data Exchange (ETDEWEB)

    Knabe, G.; Kremonke, A. [Technische Univ. Dresden (Germany). Inst. fuer Thermodynamik und Technische Gebaeudeausruestung; Bach, H.; Bauer, M.; Eisenmann, G.; Haupt, C.; Tritschler, M. [Stuttgart Univ. (Germany). Lehrstuhl fuer Heiz- und Raumlufttechnik

    1997-12-31

    The work had the aim to study the following modernization measures in a large-panel building: enhancement of thermal insulation provided by the shell of the building, enhancement of heating system efficiency, influence on user behaviour of just heating cost allocation systems. Further, general statements are made regarding the following aspects of building modernization: energy consumption analysis, planning, user behaviour and system management. (MSK) [Deutsch] Ziel der Untersuchungen war es an einem Plattenbau folgende Modernisierungsmassnahmen zu untersuchen: Verbesserung der Waermedaemmung der Gebaeudehuellkonstruktion, Effizienzsteigerung des Heizsystems, Beeinflussung des Nutzerverhaltens durch gerechte Heizkostenverteilsysteme. Zudem werden allgemeine Aussagen zur Modernisierung von Gebaeuden zu folgenden Bereichen vorgelegt: Energiediagnose, Planung, Nutzerverhalten sowie Betriebsmangement.

  20. The effect of cost distributions on evolutionary optimization algorithms

    NARCIS (Netherlands)

    Waas, F.; Galindo-Legaria, C.A.

    2000-01-01

    According to the No-Free-Lunch theorems of Wolpert and Macready, we cannot expect one generic optimization technique to outperform others on average. For every optimization technique there exist ``easy'' and ``hard'' problems. However, only little is known as to what criteria determine the particula

  1. Optimal monetary policy in a model with agency costs

    OpenAIRE

    Timothy Fuerst; Matthias Paustian; Charles Carlstorm

    2009-01-01

    is the optimal policy. We derive the targeting criterion that implements optimal monetary policy under commitment and show under what conditions the target depends on leads or lags of the risk premium. Finally, the paper demonstrates that the degree of price stickiness and/or the nature of monetary policy alter the endogenous propagation of net worth across time.

  2. Globally Optimal Path Planning with Anisotropic Running Costs

    Science.gov (United States)

    2013-03-01

    Proceedings of the American Control Conference , pp...Jacques, D. R. & Pachter, M. (2002) Air vehicle optimal trajectories between two radars, in Proceedings of the American Control Conference . Pachter...M. & Hebert, J. (2001) Optimal aircraft trajectories for radar exposure mini- mization, in Proceedings of the American Control Conference .

  3. Exergoeconomic performance optimization of an endoreversible intercooled regenerated Brayton cogeneration plant. Part 2: Heat conductance allocation and pressure ratio optimization

    Directory of Open Access Journals (Sweden)

    Bo Yang, Lingen Chen, Fengrui Sun

    2011-03-01

    Full Text Available Finite time exergoeconomic performance of an endoreversible intercooled regenerative Brayton cogeneration plant is optimized based on the model which is established using finite time thermodynamic in Part 1 of this paper. It is found that the optimal heat conductance allocation of the regenerator is zero. When the total pressure ratio and the heat conductance allocation of the regenerator are fixed, it is shown that there exist an optimal intercooling pressure ratio, and a group of optimal heat conductance allocations among the hot-, cold- and consumer-side heat exchangers and the intercooler, which correspond to a maximum dimensionless profit rate. When the total pressure ratio is variable, there exists an optimal total pressure ratio which corresponds to a double-maximum dimensionless profit rate, and the corresponding exergetic efficiency is obtained. The effects of the total heat exchanger conductance, price ratios and the consumer-side temperature on the double-maximum dimensionless profit rate and the corresponding exergetic efficiency are discussed. It is found that there exists an optimal consumer-side temperature which corresponds to a thrice-maximum dimensionless profit rate.

  4. Estimation and optimization of heat transfer and overall presure drop for a shell and tube heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Bala Bhaskara [Dept. of Mechanical Engineering, SISTAM College, JNTU, Kakinada (India); Raju, V. Ramachandra [Dept. of Mechanical Engineering, JNTU, Kakinada (India); Deepak, B. B V. L. [Dept. of Industrial Design, National Institute of Technology, Rourkela (India)

    2017-01-15

    Most thermal/chemical industries are equipped with heat exchangers to enhance thermal efficiency. The performance of heat exchangers highly depends on design modifications in the tube side, such as the cross-sectional area, orientation, and baffle cut of the tube. However, these parameters do not exhibit a specific relation to determining the optimum design condition for shell and tube heat exchangers with a maximum heat transfer rate and reduced pressure drops. Accordingly, experimental and numerical simulations are performed for a heat exchanger with varying tube geometries. The heat exchanger considered in this investigation is a single-shell, multiple-pass device. A Generalized regression neural network (GRNN) is applied to generate a relation among the input and output process parameters for the experimental data sets. Then, an Artificial immune system (AIS) is used with GRNN to obtain optimized input parameters. Lastly, results are presented for the developed hybrid GRNN-AIS approach.

  5. Optimization of SiO2 nanoparticle mass concentration and heat input on a loop heat pipe

    Directory of Open Access Journals (Sweden)

    Prem Gunnasegaran

    2015-09-01

    Full Text Available This study presents the effect of nanoparticle mass concentration and heat input based on the total thermal resistance (Rth of loop heat pipe (LHP, employed for PC-CPU cooling. In this study, silica nanoparticles (SiO2 in water with particle mass concentration ranged from 0% (pure water to 3% is considered as the working fluid within the LHP. The experimental design and optimization is accomplished by the design of experimental tool, Response Surface Methodology (RSM. The results show that the nanoparticle mass concentration and the heat input have significant effect on the Rth of LHP. For a given heat input, the Rth is found to decrease with the increase of the nanoparticle mass concentration up to 0.5% and increased thereafter. It is also found that the Rth is decreased when the heat input is increased from 20 W to 60 W. The results are optimized with the objective of minimizing the Rth, using Design-Expert software, and the optimized nanoparticle mass concentration and heat input are 0.48% and 59.97 W, respectively, the minimum Rth being 2.66 (ºC/W. The existence of an optimum nanoparticle mass concentration and heat input are the predominant factors for the improvement in the thermal performance of nanofluid-charged LHP.

  6. Optimizing calibration intervals for specific applications to reduce maintenance costs

    Energy Technology Data Exchange (ETDEWEB)

    Collier, Steve; Holland, Jack [Servomex Group, Crowborough (United Kingdom)

    2009-11-01

    The introduction of the Servomex MultiExact 5400 analyzer has presented an opportunity to review the cost of ownership and how improvements to an analyzer's performance may be used to reduce this. Until now, gas analyzer manufacturers have taken a conservative approach to calibration intervals based on site practices and experience covering a wide range of applications. However, if specific applications are considered, then there is an opportunity to reduce costs by increasing calibration intervals. This paper demonstrates how maintenance costs may be reduced by increasing calibration intervals for those gas analyzers used for monitoring Air Separation Units (ASUs) without detracting from their performance.(author)

  7. Optimal Cooling Load and COP Relationship of a Four-Heat-Reservoir Endoreversible Absorption Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Chih Wu

    2004-06-01

    Full Text Available Abstract: On the basis of a four-heat-reservoir endoreversible absorption refrigeration cycle model, another linear heat transfer law [i.e., the heat-flux] is adopted, the fundamental optimal relation between the coefficient of performance (COP and the cooling load, as well as the maximum cooling load and the corresponding COP of the cycle coupled to constant-temperature heat reservoirs are derived by using finite-time thermodynamics or thermodynamic optimization. The optimal distribution of the heat-transfer surface areas is also obtained. Moreover, the effects of the cycle parameters on the COP and the cooling load of the cycle are studied by detailed numerical examples. The results obtained herein are of importance to the optimal design and performance improvement of an absorption refrigeration cycle.

  8. Cost related sensitivity analysis for optimal operation of a grid-parallel PEM fuel cell power plant

    Science.gov (United States)

    El-Sharkh, M. Y.; Tanrioven, M.; Rahman, A.; Alam, M. S.

    Fuel cell power plants (FCPP) as a combined source of heat, power and hydrogen (CHP&H) can be considered as a potential option to supply both thermal and electrical loads. Hydrogen produced from the FCPP can be stored for future use of the FCPP or can be sold for profit. In such a system, tariff rates for purchasing or selling electricity, the fuel cost for the FCPP/thermal load, and hydrogen selling price are the main factors that affect the operational strategy. This paper presents a hybrid evolutionary programming and Hill-Climbing based approach to evaluate the impact of change of the above mentioned cost parameters on the optimal operational strategy of the FCPP. The optimal operational strategy of the FCPP for different tariffs is achieved through the estimation of the following: hourly generated power, the amount of thermal power recovered, power trade with the local grid, and the quantity of hydrogen that can be produced. Results show the importance of optimizing system cost parameters in order to minimize overall operating cost.

  9. The Optimization of Transportation Costs in Logistics Enterprises with Time-Window Constraints

    Directory of Open Access Journals (Sweden)

    Qingyou Yan

    2015-01-01

    Full Text Available This paper presents a model for solving a multiobjective vehicle routing problem with soft time-window constraints that specify the earliest and latest arrival times of customers. If a customer is serviced before the earliest specified arrival time, extra inventory costs are incurred. If the customer is serviced after the latest arrival time, penalty costs must be paid. Both the total transportation cost and the required fleet size are minimized in this model, which also accounts for the given capacity limitations of each vehicle. The total transportation cost consists of direct transportation costs, extra inventory costs, and penalty costs. This multiobjective optimization is solved by using a modified genetic algorithm approach. The output of the algorithm is a set of optimal solutions that represent the trade-off between total transportation cost and the fleet size required to service customers. The influential impact of these two factors is analyzed through the use of a case study.

  10. Heating with straw. Cost structure of the agricultural heat production; Heizen mit Stroh. Kostenstruktur der landwirtschaftlichen Waermeerzeugung

    Energy Technology Data Exchange (ETDEWEB)

    Dietze, Matthias; Heilmann, Hubert [Landesforschungsanstalt fuer Landwirtschaft und Fischerei Mecklenburg-Vorpommern, Guelzow (Germany). Inst. fuer Pflanzenproduktion und Betriebswirtschaft

    2012-07-01

    In the present investigation the economy of straw heating is compared to an oil heating for pigs and poultry farms. High requirements in terms of the raw material and the high workloads during grain harvest make an appropriate mechanization necessary. The costs of the straw salvage vary between 50 and 100 Euro per ton. They depend on the grade of machine utilization, the transport distance, necessary investments in stockroom and the price for plant nutrients. Related to the energy content the costs amount on 1,25 to 2,5 Eurocent per kilowatt-hour. The energetically use of agricultural residuals has a great economical potential. But most important is to achieve a positive humus balance. (orig.)

  11. The Application of Maximum Principle in Supply Chain Cost Optimization

    National Research Council Canada - National Science Library

    Zhou Ling; Wang Jun

    2013-01-01

    In this paper, using the maximum principle for analyzing dynamic cost, we propose a new two-stage supply chain model of the manufacturing-assembly mode for high-tech perishable products supply chain...

  12. Cost optimization of load carrying thin-walled precast high performance concrete sandwich panels

    DEFF Research Database (Denmark)

    Hodicky, Kamil; Hansen, Sanne; Hulin, Thomas

    2015-01-01

    and HPCSP’s geometrical parameters as well as on material cost function in the HPCSP design. Cost functions are presented for High Performance Concrete (HPC), insulation layer, reinforcement and include labour-related costs. The present study reports the economic data corresponding to specific manufacturing......The paper describes a procedure to find the structurally and thermally efficient design of load-carrying thin-walled precast High Performance Concrete Sandwich Panels (HPCSP) with an optimal economical solution. A systematic optimization approach is based on the selection of material’s performances....... The solution of the optimization problem is performed in the computer package software Matlab® with SQPlab package and integrates the processes of HPCSP design, quantity take-off and cost estimation. The proposed optimization process outcomes in complex HPCSP design proposals to achieve minimum cost of HPCSP....

  13. OPTIMIZATION METHOD AND SOFTWARE FOR FUEL COST REDUCTION IN CASE OF ROAD TRANSPORT ACTIVITY

    Directory of Open Access Journals (Sweden)

    György Kovács

    2017-06-01

    Full Text Available The transport activity is one of the most expensive processes in the supply chain and the fuel cost is the highest cost among the cost components of transportation. The goal of the research is to optimize the transport costs in case of a given transport task both by the selecting the optimal petrol station and by determining the optimal amount of the refilled fuel. Recently, in practice, these two decisions have not been made centrally at the forwarding company, but they depend on the individual decision of the driver. The aim of this study is to elaborate a precise and reliable mathematical method for selecting the optimal refuelling stations and determining the optimal amount of the refilled fuel to fulfil the transport demands. Based on the elaborated model, new decision-supporting software is developed for the economical fulfilment of transport trips.

  14. Investigation of Cost and Energy Optimization of Drinking Water Distribution Systems.

    Science.gov (United States)

    Cherchi, Carla; Badruzzaman, Mohammad; Gordon, Matthew; Bunn, Simon; Jacangelo, Joseph G

    2015-11-17

    Holistic management of water and energy resources through energy and water quality management systems (EWQMSs) have traditionally aimed at energy cost reduction with limited or no emphasis on energy efficiency or greenhouse gas minimization. This study expanded the existing EWQMS framework and determined the impact of different management strategies for energy cost and energy consumption (e.g., carbon footprint) reduction on system performance at two drinking water utilities in California (United States). The results showed that optimizing for cost led to cost reductions of 4% (Utility B, summer) to 48% (Utility A, winter). The energy optimization strategy was successfully able to find the lowest energy use operation and achieved energy usage reductions of 3% (Utility B, summer) to 10% (Utility A, winter). The findings of this study revealed that there may be a trade-off between cost optimization (dollars) and energy use (kilowatt-hours), particularly in the summer, when optimizing the system for the reduction of energy use to a minimum incurred cost increases of 64% and 184% compared with the cost optimization scenario. Water age simulations through hydraulic modeling did not reveal any adverse effects on the water quality in the distribution system or in tanks from pump schedule optimization targeting either cost or energy minimization.

  15. Optimization of stability index versus first strike cost

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, G.H.

    1997-05-01

    This note studies the impact of maximizing the stability index rather than minimizing the first strike cost in choosing offensive missile allocations. It does so in the context of a model in which exchanges between vulnerable missile forces are modeled probabilistically, converted into first and second strike costs through approximations to the value target sets at risk, and the stability index is taken to be their ratio. The value of the allocation that minimizes the first strike cost for both attack preferences are derived analytically. The former recovers results derived earlier. The latter leads to an optimum at unity allocation for which the stability index is determined analytically. For values of the attack preference greater than about unity, maximizing the stability index increases the cost of striking first 10--15%. For smaller values of the attack preference, maximizing the index increases the second strike cost a similar amount. Both are stabilizing, so if both sides could be trusted to target on missiles in order to minimize damage to value and maximize stability, the stability index for vulnerable missiles could be increased by about 15%. However, that would increase the cost to the first striker by about 15%. It is unclear why--having decided to strike--he would do so in a way that would increase damage to himself.

  16. Lp and L∞ Norm Estimates of the Cost of the Controllability for Heat Equations

    Institute of Scientific and Technical Information of China (English)

    Pei Dong LEI; Xu LIU; Hang GAO

    2009-01-01

    This paper is concerned with the bound of the cost of approximate controllability and null controllability of heat equations, i.e., the minimal Lp norm and L∞ norm of a control needed to control the system approximately or a control needed to steer the state of the system to zero. The methods we use combine observability inequalities, energy estimates for heat equations and the dual theory.

  17. Evaluation of the operational cost savings potential from a D-CHP system based on a monthly power-to-heat ratio analysis

    Directory of Open Access Journals (Sweden)

    Alta Knizley

    2015-12-01

    Full Text Available This paper focuses on the analysis of a combined heat and power (CHP system utilizing two power generation units operating simultaneously under differing operational strategies (D-CHP on the basis of operational cost savings. A cost optimization metric, based on the facility monthly power-to-heat ratio (PHR, is presented in this paper. The PHR is defined as the ratio between the facility electric load and thermal load. Previous work in this field has suggested that D-CHP system performance may be improved by limiting operation of the system to months in which the PHR is relatively low. The focus of this paper is to illustrate how the facility PHR parameter could be used to establish the potential of a D-CHP system to reduce operational cost with respect to traditional CHP systems and conventional systems with separate heating and power. This paper analyzes the relationship between the PHR and the operational cost savings of eight different benchmark buildings. Achieving operational cost savings through optimal operation based on monthly PHR for these building types can enhance the implementation potential of D-CHP and CHP systems. Results indicate that the PHR parameter can be used to predict the potential for a D-CHP system to reduce the operational cost.

  18. Sample size calculation in cost-effectiveness cluster randomized trials: optimal and maximin approaches.

    Science.gov (United States)

    Manju, Md Abu; Candel, Math J J M; Berger, Martijn P F

    2014-07-10

    In this paper, the optimal sample sizes at the cluster and person levels for each of two treatment arms are obtained for cluster randomized trials where the cost-effectiveness of treatments on a continuous scale is studied. The optimal sample sizes maximize the efficiency or power for a given budget or minimize the budget for a given efficiency or power. Optimal sample sizes require information on the intra-cluster correlations (ICCs) for effects and costs, the correlations between costs and effects at individual and cluster levels, the ratio of the variance of effects translated into costs to the variance of the costs (the variance ratio), sampling and measuring costs, and the budget. When planning, a study information on the model parameters usually is not available. To overcome this local optimality problem, the current paper also presents maximin sample sizes. The maximin sample sizes turn out to be rather robust against misspecifying the correlation between costs and effects at the cluster and individual levels but may lose much efficiency when misspecifying the variance ratio. The robustness of the maximin sample sizes against misspecifying the ICCs depends on the variance ratio. The maximin sample sizes are robust under misspecification of the ICC for costs for realistic values of the variance ratio greater than one but not robust under misspecification of the ICC for effects. Finally, we show how to calculate optimal or maximin sample sizes that yield sufficient power for a test on the cost-effectiveness of an intervention.

  19. Efficient Solutions and Cost-Optimal Analysis for Existing School Buildings

    Directory of Open Access Journals (Sweden)

    Paolo Maria Congedo

    2016-10-01

    Full Text Available The recast of the energy performance of buildings directive (EPBD describes a comparative methodological framework to promote energy efficiency and establish minimum energy performance requirements in buildings at the lowest costs. The aim of the cost-optimal methodology is to foster the achievement of nearly zero energy buildings (nZEBs, the new target for all new buildings by 2020, characterized by a high performance with a low energy requirement almost covered by renewable sources. The paper presents the results of the application of the cost-optimal methodology in two existing buildings located in the Mediterranean area. These buildings are a kindergarten and a nursery school that differ in construction period, materials and systems. Several combinations of measures have been applied to derive cost-effective efficient solutions for retrofitting. The cost-optimal level has been identified for each building and the best performing solutions have been selected considering both a financial and a macroeconomic analysis. The results illustrate the suitability of the methodology to assess cost-optimality and energy efficiency in school building refurbishment. The research shows the variants providing the most cost-effective balance between costs and energy saving. The cost-optimal solution reduces primary energy consumption by 85% and gas emissions by 82%–83% in each reference building.

  20. A genetic algorithm technique to optimize the configuration of heat storage in DH networks

    Directory of Open Access Journals (Sweden)

    Amru Rizal Razani

    2016-12-01

    Full Text Available The technical and economical evaluation of heat storage layout and configuration in the DH network is one of important aspect for optimizing the heat production from the heat supplier’s point of view in one side as well as to satisfy the heat customer demand in the other side. Generally, the state of the art technique has considered three optional planning layouts for DH network. A classical network with centralized heat storage at Combined Heat and Power (CHP plant, decentralized storages in the network, and decentralized small storages at the substations or in the customer building. In this paper, through the use of genetic algorithm technique, comparison of three different scenarios is presented to evaluate the optimal planning of heat storage layout in CHP based DH supply system according to economical and technical aspects in the network.

  1. Minimizing Energy Cost in Electric Arc Furnace Steel Making by Optimal Control Designs

    Directory of Open Access Journals (Sweden)

    Er-wei Bai

    2014-01-01

    Full Text Available Production cost in steel industry is a challenge issue and energy optimization is an important part. This paper proposes an optimal control design aiming at minimizing the production cost of the electric arc furnace steel making. In particular, it is shown that with the structure of an electric arc furnace, the production cost which is a linear programming problem can be solved by the tools of linear quadratic regulation control design that not only provides an optimal solution but also is in a feedback form. Modeling and control designs are validated by the actual production data sets.

  2. Data of cost-optimality and technical solutions for high energy performance buildings in warm climate.

    Science.gov (United States)

    Zacà, Ilaria; D'Agostino, Delia; Maria Congedo, Paolo; Baglivo, Cristina

    2015-09-01

    The data reported in this article refers to input and output information related to the research articles entitled Assessment of cost-optimality and technical solutions in high performance multi-residential buildings in the Mediterranean area by Zacà et al. (Assessment of cost-optimality and technical solutions in high performance multi-residential buildings in the Mediterranean area, in press.) and related to the research article Cost-optimal analysis and technical comparison between standard and high efficient mono residential buildings in a warm climate by Baglivo et al. (Energy, 2015, 10.1016/j.energy.2015.02.062, in press).

  3. Life cycle cost optimization of buildings with regard to energy use, thermal indoor environment and daylight

    DEFF Research Database (Denmark)

    Nielsen, Toke Rammer; Svendsen, Svend

    2002-01-01

    Buildings represent a large economical investment and have long service lives through which expenses for heating, cooling, maintenance and replacement depends on the chosen building design. Therefore, the building cost should not only be evaluated by the initial investment cost but rather by the ...

  4. Selected cost considerations for geothermal district heating in existing single-family residential areas

    Energy Technology Data Exchange (ETDEWEB)

    Rafferty, K.

    1996-06-01

    In the past, district heating (geothermal or conventionally fueled) has not been widely applied to the single-family residential sector. Low-heat load density is the commonly cited reason for this. Although it`s true that load density in these areas is much lower than for downtown business districts, other frequently overlooked factors may compensate for load density. In particular, costs for distribution system installation can be substantially lower in some residential areas due to a variety of factors. This reduced development cost may partially compensate for the reduced revenue resulting from low-load density. This report examines cost associated with the overall design of the system (direct or indirect system design), distribution piping installation, and customer branch lines. It concludes with a comparison of the costs for system development and the revenue from an example residential area.

  5. Optimal production policy for a remanufacturing system with virtual inventory cost

    Science.gov (United States)

    Nakashima, Kenichi; Gupta, Surendra M.

    2005-11-01

    This paper deals with a cost management problem of a remanufacturing system with stochastic demand. We model the system with consideration for two types of inventories. One is the actual product inventory in the factory. The other is the virtual inventory that is being used by the customer. For this virtual inventory, it should be required to consider an operational cost that we need in order to observe and check the quantity of the inventory. We call this the virtual inventory cost and model the system by including it. We define the state of the remanufacturing system by the two inventory levels. It is assumed that the cost function is composed of various cost factors such as holding, backlog and manufacturing costs. We obtain the optimal policy that minimizes the expected average cost per period. Numerical results reveal the effects of the factors on the optimal policy.

  6. Improved mine blast algorithm for optimal cost design of water distribution systems

    Science.gov (United States)

    Sadollah, Ali; Guen Yoo, Do; Kim, Joong Hoon

    2015-12-01

    The design of water distribution systems is a large class of combinatorial, nonlinear optimization problems with complex constraints such as conservation of mass and energy equations. Since feasible solutions are often extremely complex, traditional optimization techniques are insufficient. Recently, metaheuristic algorithms have been applied to this class of problems because they are highly efficient. In this article, a recently developed optimizer called the mine blast algorithm (MBA) is considered. The MBA is improved and coupled with the hydraulic simulator EPANET to find the optimal cost design for water distribution systems. The performance of the improved mine blast algorithm (IMBA) is demonstrated using the well-known Hanoi, New York tunnels and Balerma benchmark networks. Optimization results obtained using IMBA are compared to those using MBA and other optimizers in terms of their minimum construction costs and convergence rates. For the complex Balerma network, IMBA offers the cheapest network design compared to other optimization algorithms.

  7. Efficient Guiding Towards Cost-Optimality in Uppaal

    DEFF Research Database (Denmark)

    Behrmann, Gerd; Fehnker, Ansgar; Hune, Thomas S.

    2001-01-01

    In this paper we present an algorithm for efficiently computing the minimum cost of reaching a goal state in the model of Uniformly Priced Timed Automata (UPTA). This model can be seen as a submodel of the recently suggested model of linearly priced timed automata, which extends timed automata...

  8. Heat and mass transfer intensification and shape optimization a multi-scale approach

    CERN Document Server

    2013-01-01

    Is the heat and mass transfer intensification defined as a new paradigm of process engineering, or is it just a common and old idea, renamed and given the current taste? Where might intensification occur? How to achieve intensification? How the shape optimization of thermal and fluidic devices leads to intensified heat and mass transfers? To answer these questions, Heat & Mass Transfer Intensification and Shape Optimization: A Multi-scale Approach clarifies  the definition of the intensification by highlighting the potential role of the multi-scale structures, the specific interfacial area, the distribution of driving force, the modes of energy supply and the temporal aspects of processes.   A reflection on the methods of process intensification or heat and mass transfer enhancement in multi-scale structures is provided, including porous media, heat exchangers, fluid distributors, mixers and reactors. A multi-scale approach to achieve intensification and shape optimization is developed and clearly expla...

  9. Optimization of Regulation Valve Location for Heating System

    Institute of Scientific and Technical Information of China (English)

    LIU Ling-ling; CHEN Hong-bing; LI De-ying

    2009-01-01

    This paper mainly studied how to determine the best location of the self-operated flow control valve at the heating system entrance.Since the location of regulating valve directly affects the pipe network per-formance,the simulation and analysis of pressure change in heating system WaS carried out with ComputationalFluid Dynamics(CFD)software.The study shows the best location of regulating valve varies with the change of the supply and return pipe length when the heating area of each user is small,and when the heating area of each user is large(2000000~3000000m2),the best location is on the supply pipe.

  10. Optimization of idealized ORC in domestic combined heat and power generation

    Science.gov (United States)

    Rybiński, Witold; Mikielewicz, Jarosław

    2013-09-01

    Organic Rankine cycle (ORC) is used, amongst the others, in geothermal facilities, in waste heat recovery or in domestic combined heat and power (CHP) generation. The paper presents optimization of an idealized ORC equivalent of the Carnot cycle with non-zero temperature difference in heat exchangers and with energy dissipation caused by the viscous fluid flow. In this analysis the amount of heat outgoing from the ORC is given. Such a case corresponds to the application of an ORC in domestic CHP. This assumption is different from the most of ORC models where the incoming amount of heat is given.

  11. Optimization of the thermal performance of multi-layer silicon microchannel heat sinks

    Directory of Open Access Journals (Sweden)

    Xu Shanglong

    2016-01-01

    Full Text Available The objective is to optimize the configuration sizes and thermal performance of a multilayer silicon microchannel heat sink by the thermal resistance network model. The effect of structural parameter on the thermal resistance is analyzed by numercal simulation. Taking the thermal resistance as an objective function, a nonlinear and multi-constrained optimization model are proposed for the silicon microchannel heat sink in electronic chips cooling. The sequential quadratic programming (SQP method is used to do the optimization design of the configuration sizes of the microchannel. For the heat sink with the size of 20mm×20mm and the power of 400 W, the optimized microchannel number, layer, height and width are 40 and 2, 2.2mm and 0.2mm, respectively, and its corresponding total thermal resistance for whole microchannel heat sink is 0.0424 K/W.

  12. Game theory approach to optimal capital cost allocation in pollution control

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    This paper tries to integrate game theory, a very usefultool to resolve conflict phenomena, with optimal capital costallocation issue in total emission control. First the necessity ofallocating optimal capital costs fairly and reasonably amongpolluters in total emission control is analyzed. Then thepossibility of applying game theory to the issue of the optimalcapital cost allocation is expounded. Next the cooperative N-person game model of the optimal capital cost allocation and itssolution ways including method based on Shapley value, least coremethod, weak least core methods, proportional least core method,CGA method, MCRS method and so on are delineated. Finally throughapplication of these methods it is concluded that to apply gamethory in the optimal capital cost allocation issue is helpful toimplement the total emission control planning schemes successfully,to control pollution effectively, and to ensure sustainable development.

  13. On the optimality equation for average cost Markov control processes with Feller transition probabilities

    Science.gov (United States)

    Jaskiewicz, Anna; Nowak, Andrzej S.

    2006-04-01

    We consider Markov control processes with Borel state space and Feller transition probabilities, satisfying some generalized geometric ergodicity conditions. We provide a new theorem on the existence of a solution to the average cost optimality equation.

  14. Cost-Optimal Design of a 3-Phase Core Type Transformer by Gradient Search Technique

    Science.gov (United States)

    Basak, R.; Das, A.; Sensarma, A. K.; Sanyal, A. N.

    2014-04-01

    3-phase core type transformers are extensively used as power and distribution transformers in power system and their cost is a sizable proportion of the total system cost. Therefore they should be designed cost-optimally. The design methodology for reaching cost-optimality has been discussed in details by authors like Ramamoorty. It has also been discussed in brief in some of the text-books of electrical design. The paper gives a method for optimizing design, in presence of constraints specified by the customer and the regulatory authorities, through gradient search technique. The starting point has been chosen within the allowable parameter space the steepest decent path has been followed for convergence. The step length has been judiciously chosen and the program has been maneuvered to avoid local minimal points. The method appears to be best as its convergence is quickest amongst different optimizing techniques.

  15. A Thesis on Design Optimization of Heat Sink in Power Electronics

    Directory of Open Access Journals (Sweden)

    P.Chennakesavarao

    2014-10-01

    Full Text Available The heat sinks are used in electronic systems to remove heat from the chip and effectively transfer it to the ambient. The heat sink geometry is designed by the mechanical engineers with the primary aim of reducing the thermal resistance of the heat sink for better cooling in the electronic systems. Due to the proximity of the heat sink with the ICs, the RF fields created by RF currents in the ICs/PCBs gets coupled to heat sinks. Hence, the coupled RF current can cause radiated emission. This radiated noise from the device can couple and disturb the functioning of the nearby electronic systems. Also this radiated emission from the device poses a problem to the system compliance with respect to EMI/EMC regulations. The international EMI/EMC standards require the radiated emission from the electronic devices to be kept below the specified limits. As a result the design of Heat Sink is very important factor for the efficient operation of the electronic equipment. In this project design optimization of a Heat sink in a Power amplifier is performed to reduce the weight and size .Power amplifier is electronic equipment mounted in an army vehicle. The power modules inside the amplifier generates a heat of 1440 Watts and a temperature of 140 0c.Two Heat sinks are used to dissipate the heat generated inside the equipment and maintain a temperature of less than 850c. The existing heat sink which is being used is weighing around 10.3kgs and height of 51mm; as a result the unit is very robust. The objective of my project is To design & optimize the heat sink to reduce the weight and size. The optimized heat sink should also dissipate heat generated by power modules and maintain a temperature of less than 850c inside. To achieve the design a steady state thermal analysis will be performed on the heat sink and plot the Temperature distribution on the fins. Based on the above analysis results we will increase/decrease the number of fins, thickness of fins, and

  16. An Optimal Operating Strategy for Battery Life Cycle Costs in Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Yinghua Han

    2014-01-01

    Full Text Available Impact on petroleum based vehicles on the environment, cost, and availability of fuel has led to an increased interest in electric vehicle as a means of transportation. Battery is a major component in an electric vehicle. Economic viability of these vehicles depends on the availability of cost-effective batteries. This paper presents a generalized formulation for determining the optimal operating strategy and cost optimization for battery. Assume that the deterioration of the battery is stochastic. Under the assumptions, the proposed operating strategy for battery is formulated as a nonlinear optimization problem considering reliability and failure number. And an explicit expression of the average cost rate is derived for battery lifetime. Results show that the proposed operating strategy enhances the availability and reliability at a low cost.

  17. Optimizing Transmission Service Cost of Khuzestan Regional Grid Based on Nsga-Ii Algorithm

    Science.gov (United States)

    Shooshtari, Alireza Tavakoli; Joorabian, Mahmood; Milani, Armin Ebrahimi; Gholamzadeh, Arash

    2011-06-01

    Any plan for modeling the components of transmission service costs should be able to consider congestion as well as loss cost. Assessing the real value of congestion and loss costs in each network has a substantial contribution to analyze the grid's weaknesses in order to release capacity of power network. As much as the amount of congestion and loss costs in the transmission grid reduces the amount of power passing through transmission lines increases. Therefore, the transmission service cost will be optimized and revenues of the regional electricity company from transmission services will be increased. In this paper, a new power flow algorithm with congestion and loss considerations of a power network is presented. Thus, optimal power flow and a multi-objectives optimization algorithm, called NSGA-II, is used in this work. The real data of Khuzestan regional power grid is implemented to confirm the efficiency of proposed method.

  18. An Optimization System for Concrete Life Cycle Cost and Related CO2 Emissions

    Directory of Open Access Journals (Sweden)

    Tae Hyoung Kim

    2016-04-01

    Full Text Available An optimization system that supports the production of concrete while minimizing carbon dioxide (CO2 emissions or costs is presented that incorporates an evolution algorithm for the materials’ mix design stage, a trigonometric function for the transportation stage, and a stochastic model for the manufacturing stage. A case study demonstrates that applying the optimization system reduced CO2 emissions by 34% compared to the standard concrete production processes typically used. When minimizing the cost of concrete production was prioritized, the cost dropped by 1% compared to the cost of conventional concrete production. These findings confirm that this optimization system helps with the design of the concrete mix and the choice of a material supplier, thus reducing both CO2 emissions and costs.

  19. Thermal control of power supplies with electronic packaging techniques. [using low cost heat pipes

    Science.gov (United States)

    1977-01-01

    The integration of low-cost commercial heat pipes in the design of a NASA candidate standard modular power supply with a 350 watt output resulted in a 44% weight reduction. Part temperatures were also appreciably reduced, increasing the environmental capability of the unit. A complete 350- watt modular power converter was built and tested to evaluate thermal performance of the redesigned supply.

  20. Use of multilevel modeling for determining optimal parameters of heat supply systems

    Science.gov (United States)

    Stennikov, V. A.; Barakhtenko, E. A.; Sokolov, D. V.

    2017-07-01

    The problem of finding optimal parameters of a heat-supply system (HSS) is in ensuring the required throughput capacity of a heat network by determining pipeline diameters and characteristics and location of pumping stations. Effective methods for solving this problem, i.e., the method of stepwise optimization based on the concept of dynamic programming and the method of multicircuit optimization, were proposed in the context of the hydraulic circuit theory developed at Melentiev Energy Systems Institute (Siberian Branch, Russian Academy of Sciences). These methods enable us to determine optimal parameters of various types of piping systems due to flexible adaptability of the calculation procedure to intricate nonlinear mathematical models describing features of used equipment items and methods of their construction and operation. The new and most significant results achieved in developing methodological support and software for finding optimal parameters of complex heat supply systems are presented: a new procedure for solving the problem based on multilevel decomposition of a heat network model that makes it possible to proceed from the initial problem to a set of interrelated, less cumbersome subproblems with reduced dimensionality; a new algorithm implementing the method of multicircuit optimization and focused on the calculation of a hierarchical model of a heat supply system; the SOSNA software system for determining optimum parameters of intricate heat-supply systems and implementing the developed methodological foundation. The proposed procedure and algorithm enable us to solve engineering problems of finding the optimal parameters of multicircuit heat supply systems having large (real) dimensionality, and are applied in solving urgent problems related to the optimal development and reconstruction of these systems. The developed methodological foundation and software can be used for designing heat supply systems in the Central and the Admiralty regions in

  1. A Cost-Effective Approach to Optimizing Microstructure and Magnetic Properties in Ce17Fe78B6 Alloys

    Directory of Open Access Journals (Sweden)

    Xiaohua Tan

    2017-07-01

    Full Text Available Optimizing fabrication parameters for rapid solidification of Re-Fe-B (Re = Rare earth alloys can lead to nanocrystalline products with hard magnetic properties without any heat-treatment. In this work, we enhanced the magnetic properties of Ce17Fe78B6 ribbons by engineering both the microstructure and volume fraction of the Ce2Fe14B phase through optimization of the chamber pressure and the wheel speed necessary for quenching the liquid. We explored the relationship between these two parameters (chamber pressure and wheel speed, and proposed an approach to identifying the experimental conditions most likely to yield homogenous microstructure and reproducible magnetic properties. Optimized experimental conditions resulted in a microstructure with homogeneously dispersed Ce2Fe14B and CeFe2 nanocrystals. The best magnetic properties were obtained at a chamber pressure of 0.05 MPa and a wheel speed of 15 m·s−1. Without the conventional heat-treatment that is usually required, key magnetic properties were maximized by optimization processing parameters in rapid solidification of magnetic materials in a cost-effective manner.

  2. Optimization of solar-powered Stirling heat engine with finite-time thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Yaqi, Li [School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Xi' an Research Institute of Hi-Tech, Xi' an, Shaanxi 710025 (China); Yaling, He; Weiwei, Wang [School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China)

    2011-01-15

    A mathematical model for the overall thermal efficiency of the solar-powered high temperature differential dish-Stirling engine with finite-rate heat transfer, regenerative heat losses, conductive thermal bridging losses and finite regeneration processes time is developed. The model takes into consideration the effect of the absorber temperature and the concentrating ratio on the thermal efficiency; radiation and convection heat transfer between the absorber and the working fluid as well as convection heat transfer between the heat sink and the working fluid. The results show that the optimized absorber temperature and concentrating ratio are at about 1100 K and 1300, respectively. The thermal efficiency at optimized condition is about 34%, which is not far away from the corresponding Carnot efficiency at about 50%. Hence, the present analysis provides a new theoretical guidance for designing dish collectors and operating the Stirling heat engine system. (author)

  3. Theoretical Analysis for Heat Transfer Optimization in Subcritical Electrothermal Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Peng Hu

    2017-02-01

    Full Text Available Electrothermal energy storage (ETES provides bulk electricity storage based on heat pump and heat engine technologies. A subcritical ETES is described in this paper. Based on the extremum principle of entransy dissipation, a geometry model is developed for heat transfer optimization for subcritical ETES. The exergy during the heat transfer process is deduced in terms of entropy production. The geometry model is validated by the extremum principle of entropy production. The theoretical analysis results show that the extremum principle of entransy dissipation is an effective criterion for the optimization, and the optimum heat transfer for different cases with the same mass flux or pressure has been discussed. The optimum heat transfer can be achieved by adjusting the mass flux and pressure of the working fluid. It also reveals that with the increase of mass flux, there is a minimum exergy in the range under consideration, and the exergy decreases with the increase of the pressure.

  4. Decision support for optimal location of local heat source for small district heating system on the example of biogas plant

    Directory of Open Access Journals (Sweden)

    Ciapała Bartłomiej

    2017-01-01

    Full Text Available Developing a new district heating system requires making decisions affecting entire range of following activities and wellness of the system. The article presents methodics of choosing optimal location and crucial customers with three approaches to optimisation process, discuss obtained results and obstacles. Further improvements and potential applications are named.

  5. Multi-objective optimization of a plain fin-and-tube heat exchanger using genetic algorithm

    Science.gov (United States)

    Juan, Du; Qin, Qian Zuo

    2014-04-01

    In the present paper, a plate fin-and-tube heat exchanger (PFTHE) is considered for optimization with air and water as working fluid, four geometric variables are taken as parameters for optimization, a Genetic Algorithm (GA) was used to search for the optimal structure sizes of the PFTHE, the maximum total heat transfer rate and the minimum total pressure drop are taken as objective functions in GA, respectively. Performance of the optimized result was evaluated and correspondingly the total heat transfer rate, the total pressure drop, the heat transfer coefficient and the local Nusselt number, j-factor and friction factor ξ are calculated respectively. Results show that the total heat transfer rate of the optimized heat exchanger increased by about 2.1-9.2% comparing with the original one, the heat transfer coefficient increased by about 8.2-14.7% and the total pressure drop decreased by about 4.4-8% in the range of Re = 1200-14000.

  6. OPTIMAL LAND CONVERSION AND GROWTH WITH UNCERTAIN BIODIVERSITY COSTS

    OpenAIRE

    Anke Leroux; John Creedy

    2005-01-01

    An important characteristic defining the threat of environmental crises is the uncertainty about their consequences for future welfare. Random processes governing ecosystem dynamics and adaptation to anthropogenic change are important sources of prevailing ecological uncertainty and contribute to the problem of how to balance economic development against natural resource conservation. The aim of this study is to examine optimal growth subject to non-linear dynamic environmental constraints. I...

  7. Final Report for Project titled High Thermal Conductivity Polymer Composites for Low-Cost Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Thibaud-Erkey, Catherine [United Technologies reserach Center, East Hartford, CT (United States); Alahyari, Abbas [United Technologies reserach Center, East Hartford, CT (United States)

    2016-12-28

    Heat exchangers (HXs) are critical components in a wide range of heat transfer applications, from HVAC (Heating Ventilation and Cooling) to automobiles to manufacturing plants. They require materials capable of transferring heat at high rates while also minimizing thermal expansion over the usage temperature range. Conventionally, metals are used for applications where effective and efficient heat exchange is required, since many metals exhibit thermal conductivity over 100 W/m K. While metal HXs are constantly being improved, they still have some inherent drawbacks due to their metal construction, in particular corrosion. Polymeric material can offer solution to such durability issues and allow designs that cannot be afforded by metal construction either due to complexity or cost. A major drawback of polymeric material is their low thermal conductivity (0.1-0.5? W/mK) that would lead to large system size. Recent improvements in the area of filled polymers have highlighted the possibility to greatly improve the thermal conductivity of polymeric materials while retaining their inherent manufacturing advantage, and have been applied to heat sink applications. Therefore, the objective of this project was to develop a robust review of materials for the manufacturing of industrial and commercial non-metallic heat exchangers. This review consisted of material identification, literature evaluation, as well as empirical and model characterization, resulting in a database of relevant material properties and characteristics to provide guidance for future heat exchanger development.

  8. Thermoelectric generator sandwiched in a crossflow heat exchanger with optimal connectivity between modules

    Energy Technology Data Exchange (ETDEWEB)

    Belanger, Simon [Departement de genie mecanique, Universite Laval, 1065, avenue de la Medecine, Quebec City, QC, G1V 0A6 (Canada); Gosselin, Louis, E-mail: Louis.Gosselin@gmc.ulaval.ca [Departement de genie mecanique, Universite Laval, 1065, avenue de la Medecine, Quebec City, QC, G1V 0A6 (Canada)

    2011-08-15

    Highlights: {yields} In this paper, we propose a numerical model for a crossflow heat exchanger with a thermoelectric generator sandwiched in its wall. {yields} The number of thermoelectric modules and the electrical connections between them is optimized with a genetic algorithm. {yields} Complex electric current topologies are achieved in order to maximize the total power output. - Abstract: The design of a thermoelectric generator sandwiched in the wall of a crossflow heat exchanger was optimized. A numerical model has been developed and validated. The objective function was the total power output. The design variables were the number of modules and the current in each control volume of the mesh. We also optimize directly the electrical topology of the system. A genetic algorithm was used to perform the optimizations. Complex optimal electrical topologies were achieved due to the non-uniform temperatures distributions in the heat exchanger.

  9. A KBE-enabled design framework for cost/weight optimization study of aircraft composite structures

    Science.gov (United States)

    Wang, H.; La Rocca, G.; van Tooren, M. J. L.

    2014-10-01

    Traditionally, minimum weight is the objective when optimizing airframe structures. This optimization, however, does not consider the manufacturing cost which actually determines the profit of the airframe manufacturer. To this purpose, a design framework has been developed able to perform cost/weight multi-objective optimization of an aircraft component, including large topology variations of the structural configuration. The key element of the proposed framework is a dedicated knowledge based engineering (KBE) application, called multi-model generator, which enables modelling very different product configurations and variants and extract all data required to feed the weight and cost estimation modules, in a fully automated fashion. The weight estimation method developed in this research work uses Finite Element Analysis to calculate the internal stresses of the structural elements and an analytical composite plate sizing method to determine their minimum required thicknesses. The manufacturing cost estimation module was developed on the basis of a cost model available in literature. The capability of the framework was successfully demonstrated by designing and optimizing the composite structure of a business jet rudder. The study case indicates the design framework is able to find the Pareto optimal set for minimum structural weight and manufacturing costin a very quick way. Based on the Pareto set, the rudder manufacturer is in conditions to conduct both internal trade-off studies between minimum weight and minimum cost solutions, as well as to offer the OEM a full set of optimized options to choose, rather than one feasible design.

  10. Performance evaluation and parametric optimization of a proton exchange membrane fuel cell/heat-driven heat pump hybrid system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.; Chen, J. [Department of Physics, Xiamen University, Xiamen 361005 (China)

    2012-06-15

    With the help of the current models of proton exchange membrane (PEM) fuel cells and three-heat-source heat pumps, a generic model of a PEM fuel cell/heat-driven heat pump hybrid system is established, so that the waste heat produced in the PEM fuel cell may be availably utilized. Based on the theory of electrochemistry and non-equilibrium thermodynamics, expressions for the efficiency and power output of the PEM fuel cell, the coefficient of performance and rate of pumping heat of the heat-driven heat pump, and the equivalent efficiency and power output of the hybrid system are derived. The curves of the equivalent efficiency and power output of the hybrid system varying with the electric current density and the equivalent power output versus efficiency curves are represented through numerical calculation. The general performance characteristics of the hybrid system are analyzed. The optimally operating regions of some important parameters of the hybrid system are determined. The influence of some main irreversible losses on the performance of the hybrid system is discussed in detail. The advantages of the hybrid system are revealed. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Optimization of a thermoelectric generator subsystem for high temperature PEM fuel cell exhaust heat recovery

    DEFF Research Database (Denmark)

    Gao, Xin; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2014-01-01

    In previous work, a thermoelectric (TE) exhaust heat recovery subsystem for a high temperature polymer electrolyte membrane (HT-PEM) fuel cell stack was developed and modeled. Numerical simulations were conducted and have identified an optimized subsystem configuration and 4 types of compact heat...

  12. Optimization and stabilization of gold nanoparticles by using herbal plant extract with microwave heating

    OpenAIRE

    Yasmin, Akbar; Ramesh, Kumaraswamy; Rajeshkumar, Shanmugam

    2014-01-01

    In this study, we have synthesized the gold nanoparticles by using Hibiscus rosa-sinensis, a medicinal plant. The gold nanoparticles were synthesized rapidly by the involvement of microwave heating. By changing of plant extract concentration, gold solution concentration, microwave heating time and power of microwave heating the optimized condition was identified. The surface Plasmon resonance found at 520 nm confirmed the gold nanoparticles synthesis. The spherical sized nanoparticles in the ...

  13. Optimization of micro combined heat and power gas turbine by genetic algorithm

    OpenAIRE

    Yazdi Behnam Ahrar; Yazdi Behdad Ahrar; Ehyaei Mehdi Ali; Ahmadi Abolfazl

    2015-01-01

    In this paper, a comprehensive thermodynamic modeling and multi-objective optimization of a micro turbine cycle in combined heat and power generation, which provides 100KW of electric power. This CHP System is composed of air compressor, combustion chamber (CC), Air Preheater, Gas Turbine (GT) and a Heat Recovery Heat Exchanger. In this paper, at the first stage, the each part of the micro turbine cycle is modeled using thermodynamic laws. Next, with using ...

  14. Optimal Policy for Brownian Inventory Models with General Convex Inventory Cost

    Institute of Scientific and Technical Information of China (English)

    Da-cheng YAO

    2013-01-01

    We study an inventory system in which products are ordered from outside to meet demands,and the cumulative demand is governed by a Brownian motion.Excessive demand is backlogged.We suppose that the shortage and holding costs associated with the inventory are given by a general convex function.The product ordering from outside incurs a linear ordering cost and a setup fee.There is a constant leadtime when placing an order.The optimal policy is established so as to minimize the discounted cost including the inventory cost and ordering cost.

  15. Cost-Effectiveness Analysis of Heat and Moisture Exchangers in Mechanically Ventilated Critically Ill Patients

    Science.gov (United States)

    Menegueti, Mayra Goncalves; Auxiliadora-Martins, Maria; Nunes, Altacilio Aparecido

    2016-01-01

    Background Moisturizing, heating and filtering gases inspired via the mechanical ventilation (MV) circuits help to reduce the adverse effects of MV. However, there is still no consensus regarding whether these measures improve patient prognosis, shorten MV duration, decrease airway secretion and lower the incidence of ventilator associated pneumonia (VAP) and other complications. Objectives The aim of this study was to study the incremental cost-effectiveness ratio associated with the use of heat and moisture exchangers (HME) filter to prevent VAP compared with the heated humidifiers (HH) presently adopted by intensive care unit (ICU) services within the Brazilian Healthcare Unified System. Patients and Methods This study was a cost-effectiveness analysis (CEA) comparing HME and HH in preventing VAP (outcome) in mechanically ventilated adult patients admitted to an ICU of a public university hospital. Results The analysis considered a period of 12 months; MV duration of 11 and 12 days for patients in HH and HME groups, respectively and a daily cost of R$ 16.46 and R$ 13.42 for HH and HME, respectively. HME was more attractive; costs ranged from R$ 21,000.00 to R$ 22,000.00 and effectiveness was close to 0.71, compared with a cost of R$ 30,000.00 and effectiveness between 0.69 and 0.70 for HH. HME and HH differed significantly for incremental effectiveness. Even after an effectiveness gain of 1.5% in favor of HH, and despite the wide variation in the VAP rate, the HME effectiveness remained stable. The mean HME cost-effectiveness was lower than the mean HH cost-effectiveness, being the HME value close to R$ 44,000.00. Conclusions Our findings revealed that HH and HME differ very little regarding effectiveness, which makes interpretation of the results in the context of clinical practice difficult. Nonetheless, there is no doubt that HME is advantageous. This technology incurs lower direct cost. PMID:27843770

  16. Natural gas based infrared heating i greenhouses. Phase II. System optimization; Naturgasbaserad infravaerme i vaexthus. Fas II. Systemoptimering

    Energy Technology Data Exchange (ETDEWEB)

    Naeslund, Mikael [Lund Inst. of Tech. (Sweden). Dept. of Heat and Power Engineering; Schuessler, Hartmut K. [Swedish Univ. of Agricultural Sciences, Alnarp (Sweden); Ljungberg, Sven-Aake [Hoegskolan i Gaevle (Sweden). Avdelningen byggnadskvalitet

    2004-01-01

    The energy use is high in greenhouses and the cost of energy is a substantial part of the plant production cost. Infrared heating (IR) has been shown to decrease the heating demand in industrial facilities and similar buildings. IR was studied with the same purpose for greenhouses. Special emphasis has also been put on the plant growth and quality. Temperature measurements showed a slightly more than 10% decrease in net heating demand compared to the reference houses in the same facility. A saving of 10-15% should be possible with some improvements. Temperature measurements at a few selected points in the infrared heated greenhouse and thermography showed differences. Repeated thermography during similar radiation conditions showed that the production tables in the infrared heated house had differences in radiation temperature and distribution caused by inhomogenous radiation from the radiating tubes. These radiation variations cause differences in in conditions and growth for cuttings and plants in later stage of growth. The thermography study also indicate that the humidity is an important factor for redistributing the radiation and ensure an optimal micro climate when infrared heaters are used in greenhouses. These differences can be reduced if the greenhouse floor layout allows radiating tubes to be located in order to make adjacent radiation fields partly overlapping. Also, burner input, excess air ratio and radiation tube and reflector design are influential for the performance. Good design criteria are discussed. Careful studies of the root development also showed differences caused by the plant location with regard to the heating tubes. The differences were reduced after reporting and further growth. One cultivation even turned out to be more compact and thus of higher quality when infrared heating was used.

  17. The optimal path of piston motion for Otto cycle with linear phenomenological heat transfer law

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    An Otto cycle engine with internal and external irreversibilities of friction and heat leakage, in which the heat transfer between the working fluid and the environment obeys linear phenomenological heat transfer law [q ∝△(T -1)], is studied in this paper. The optimal piston motion trajectory for maximizing the work output per cycle is derived for the fixed total cycle time and fuel consumed per cycle. Optimal control theory is applied to determine the optimal piston trajectories for the cases of with and without piston acceleration constraint on each stroke and the optimal distribution of the total cycle time among the strokes. The optimal piston motion with acceleration constraint for each stroke consists of three segments, including initial maximum acceleration and final maximum deceleration boundary segments, respectively. Numerical examples for optimal configuration are provided, and the obtained results are compared with those obtained with Newton’s heat transfer law [q ∝△(T )]. The results also show that optimizing the piston motion can improve power and efficiency of the engine by more than 9%. This is primarily due to the decrease in heat leakage loss on the initial portion of the power stroke.

  18. The optimal path of piston motion for Otto cycle with linear phenomenological heat transfer law

    Institute of Scientific and Technical Information of China (English)

    XIA ShaoJun; CHEN LinGen; SUN FengRui

    2009-01-01

    An Otto cycle engine with internal and external irreversibilities of friction and heat leakage, in which the heat transfer between the working fluid and the environment obeys linear phenomenological heat transfer law [q∝△(T-1)], is studied in this paper. The optimal piston motion trajectory for maximizing the work output per cycle is derived for the fixed total cycle time and fuel consumed per cycle. Optimal control theory is applied to determine the optimal piston trajectories for the cases of with and without piston acceleration constraint on each stroke and the optimal distribution of the total cycle time among the strokes. The optimal piston motion with acceleration constraint for each stroke consists of three segments, including initial maximum acceleration and final maximum deceleration boundary segments,respectively. Numerical examples for optimal configuration are provided, and the obtained results are compared with those obtained with Newton's heat transfer law [q∝△(T)]. The results also show that optimizing the piston motion can improve power and efficiency of the engine by more than 9%. This is primarily due to the decrease in heat leakage loss on the initial portion of the power stroke.

  19. Robust Optimization for Time-Cost Tradeoff Problem in Construction Projects

    Directory of Open Access Journals (Sweden)

    Ming Li

    2014-01-01

    Full Text Available Construction projects are generally subject to uncertainty, which influences the realization of time-cost tradeoff in project management. This paper addresses a time-cost tradeoff problem under uncertainty, in which activities in projects can be executed in different construction modes corresponding to specified time and cost with interval uncertainty. Based on multiobjective robust optimization method, a robust optimization model for time-cost tradeoff problem is developed. In order to illustrate the robust model, nondominated sorting genetic algorithm-II (NSGA-II is modified to solve the project example. The results show that, by means of adjusting the time and cost robust coefficients, the robust Pareto sets for time-cost tradeoff can be obtained according to different acceptable risk level, from which the decision maker could choose the preferred construction alternative.

  20. Contingency Contractor Optimization Phase 3 Sustainment Cost by JCA Implementation Guide

    Energy Technology Data Exchange (ETDEWEB)

    Durfee, Justin David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Frazier, Christopher Rawls [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Arguello, Bryan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bandlow, Alisa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gearhart, Jared Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Katherine A [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    This document provides implementation guidance for implementing personnel group FTE costs by JCA Tier 1 or 2 categories in the Contingency Contractor Optimization Tool – Engineering Prototype (CCOT-P). CCOT-P currently only allows FTE costs by personnel group to differ by mission. Changes will need to be made to the user interface inputs pages and the database

  1. Integrated emission management for cost optimal EGR-SCR balancing in diesels

    NARCIS (Netherlands)

    Willems, F.P.T.; Mentink, P.R.; Kupper, F.; Eijnden, E.A.C. van den

    2013-01-01

    The potential of a cost-based optimization method is experimentally demonstrated on a Euro-VI heavy-duty diesel engine. Based on the actual engine-aftertreatment state, this model-based Integrated Emission Management (IEM) strategy minimizes operational (fuel and AdBlue) costs within emission constr

  2. Integrated emission management for cost optimal EGR-SCR balancing in diesels

    NARCIS (Netherlands)

    Willems, F.P.T.; Mentink, P.R.; Kupper, F.; Eijnden, E.A.C. van den

    2013-01-01

    The potential of a cost-based optimization method is experimentally demonstrated on a Euro-VI heavy-duty diesel engine. Based on the actual engine-aftertreatment state, this model-based Integrated Emission Management (IEM) strategy minimizes operational (fuel and AdBlue) costs within emission

  3. The Optimal Solution of the Model with Physical and Human Capital Adjustment Costs

    Institute of Scientific and Technical Information of China (English)

    RAO Lan-lan; CAI Dong-han

    2004-01-01

    We prove that the model with physical and human capital adjustment costs has optimal solution when the production function is increasing return and the structure of vetor fields of the model changes substantially when the prodution function from decreasing return turns to increasing return.And it is shown that the economy is improved when the coefficients of adjustment costs become small.

  4. Optimizing the Heat Exchanger Network of a Steam Reforming System

    DEFF Research Database (Denmark)

    Nielsen, Mads Pagh; Korsgaard, Anders Risum; Kær, Søren Knudsen

    2004-01-01

    Proton Exchange Membrane (PEM) based combined heat and power production systems are highly integrated energy systems. They may include a hydrogen production system and fuel cell stacks along with post combustion units optionally coupled with gas turbines. The considered system is based on a natural...... steam reforming reaction and steam must be generated. The dependence of the temperature profiles on conversion in shift reactors for gas purification is also significant. The optimum heat integration in the system is thus imperative in order to minimize the need for hot and cold utilities. A rigorous 1D...... gas steam reformer along with gas purification reactors to generate clean hydrogen suited for a PEM stack. The temperatures in the various reactors in the fuel processing system vary from around 1000°C to the stack temperature at 80°C. Furthermore, external heating must be supplied to the endothermic...

  5. Optimization study of using PTC for human body heating dissipation

    Directory of Open Access Journals (Sweden)

    Tiberiu Adrian SALAORU

    2014-06-01

    Full Text Available A better knowledge of the human body heat loses mechanisms is important for both diminishing the number of deaths during the surgical procedures of the patients under effect of full anaesthesia and increasing the efficiency of the Heating, Ventilation and Air Conditioning (HVAC systems. For these studies it is necessary to manufacture a human body mannequin having its surface temperature maintained on a value close to the real human body temperature. A number of PTC (Positive Temperature Coefficient thermistors placed on the entire external surface of the mannequin can be used for this purpose. This paper presents a study of the transient heating regime and the stability of the maintained temperature, performed on these devices.

  6. The environmental cost of subsistence: Optimizing diets to minimize footprints.

    Science.gov (United States)

    Gephart, Jessica A; Davis, Kyle F; Emery, Kyle A; Leach, Allison M; Galloway, James N; Pace, Michael L

    2016-05-15

    The question of how to minimize monetary cost while meeting basic nutrient requirements (a subsistence diet) was posed by George Stigler in 1945. The problem, known as Stigler's diet problem, was famously solved using the simplex algorithm. Today, we are not only concerned with the monetary cost of food, but also the environmental cost. Efforts to quantify environmental impacts led to the development of footprint (FP) indicators. The environmental footprints of food production span multiple dimensions, including greenhouse gas emissions (carbon footprint), nitrogen release (nitrogen footprint), water use (blue and green water footprint) and land use (land footprint), and a diet minimizing one of these impacts could result in higher impacts in another dimension. In this study based on nutritional and population data for the United States, we identify diets that minimize each of these four footprints subject to nutrient constraints. We then calculate tradeoffs by taking the composition of each footprint's minimum diet and calculating the other three footprints. We find that diets for the minimized footprints tend to be similar for the four footprints, suggesting there are generally synergies, rather than tradeoffs, among low footprint diets. Plant-based food and seafood (fish and other aquatic foods) commonly appear in minimized diets and tend to most efficiently supply macronutrients and micronutrients, respectively. Livestock products rarely appear in minimized diets, suggesting these foods tend to be less efficient from an environmental perspective, even when nutrient content is considered. The results' emphasis on seafood is complicated by the environmental impacts of aquaculture versus capture fisheries, increasing in aquaculture, and shifting compositions of aquaculture feeds. While this analysis does not make specific diet recommendations, our approach demonstrates potential environmental synergies of plant- and seafood-based diets. As a result, this study

  7. Efficient Guiding Towards Cost-Optimality in Uppaal

    DEFF Research Database (Denmark)

    Behrmann, Gerd; Fehnker, Ansgar; Hune, Thomas S.

    2001-01-01

    In this paper we present an algorithm for efficiently computing the minimum cost of reaching a goal state in the model of Uniformly Priced Timed Automata (UPTA). This model can be seen as a submodel of the recently suggested model of linearly priced timed automata, which extends timed automata...... with prices on both locations and transitions. The presented algorithm is based on a symbolic semantics of UTPA, and an efficient representation and operations based on difference bound matrices. In analogy with Dijkstra’s shortest path algorithm, we show that the search order of the algorithm can be chosen...

  8. Modelling, simulating and optimizing boiler heating surfaces and evaporator circuits

    DEFF Research Database (Denmark)

    Sørensen, Kim; Condra, Thomas Joseph; Houbak, Niels

    2003-01-01

    developed as a Differential-Algebraic-Equation system (DAE) and MATLAB has been applied for the integration of the models. In generalMATLAB has proved to be very stable for these DAE systems. Experimental verication has been carried out at a full scale plant equipped with instrumentation to verify heat....... The dynamic model has been developed for the purpose of determining boiler material temperatures and heat transfer from the ue gas side to the water-/steam side in order to simulate the circulation in the evaporator circuit and hereby the water level uctuations in the drum. The dynamic model has been...

  9. Modelling, simulating and optimizing boiler heating surfaces and evaporator circuits

    DEFF Research Database (Denmark)

    Sørensen, K.; Condra, T.; Houbak, Niels

    2003-01-01

    developed as a Differential-Algebraic-Equation system (DAE) and MATLAB has been applied for the integration of the models. In general MATLAB has proved to be very stable for these DAE systems. Experimental verification has been carried out at a full scale plant equipped with instrumentation to verify heat....... The dynamic model has been developed for the purpose of determining boiler material temperatures and heat transfer from the flue gas side to the water-/steam side in order to simulate the circulation in the evaporator circuit and hereby the water level fluctuations in the drum. The dynamic model has been...

  10. Optimizing the Heat Exchanger Network of a Steam Reforming System

    DEFF Research Database (Denmark)

    Nielsen, Mads Pagh; Korsgaard, Anders Risum; Kær, Søren Knudsen

    2004-01-01

    gas steam reformer along with gas purification reactors to generate clean hydrogen suited for a PEM stack. The temperatures in the various reactors in the fuel processing system vary from around 1000°C to the stack temperature at 80°C. Furthermore, external heating must be supplied to the endothermic...... steam reforming reaction and steam must be generated. The dependence of the temperature profiles on conversion in shift reactors for gas purification is also significant. The optimum heat integration in the system is thus imperative in order to minimize the need for hot and cold utilities. A rigorous 1D...

  11. Optimized design of district heating networks; Optimierte Auslegung von Nahwaermenetzen

    Energy Technology Data Exchange (ETDEWEB)

    Bestrzynski, Georg K.; Scholl, Stephan [Technische Univ. Braunschweig (Germany). Inst. fuer Chemische und Thermische Verfahrenstechnik; Janssen, Holger [Hochschule Hannover (Germany). Inst. fuer Energie und Klimaschutz; Luke, Andrea [Kassel Univ. (Germany). Fachgebiet fuer Technische Thermodynamik

    2012-07-01

    The construction of heating networks with small spatial dimensions and total power consumption, so-called district heating networks, is one of the key drivers for the capacity expansion of this climate-efficient technology. The widely spread implementation of cogeneration power plants with very large primary energy efficiencies in these networks specifies the reasons for the ecological special position of this technology. Unfortunately, however, there are many technical, economic and socio-economic barriers against a rapid proliferation of this technology. In line with the research project 'Possibilities and limits of district heating networks in rural structured areas under consideration of renewable energies', the resistance against a rapid expansion of capacity of this technology is to be reduced. Due to the close linkage of economic and technological shortcomings and economic presentability, the economic interests of (potential) operators are represented better. Primarily, the interactions of power, heat demand and settlement structures as well as the concepts to ensure the task of heat supply are the focus of the research activities. The integrability of continuous and discontinuous units for heat supply such as (CHP) and solar thermal systems shall be examined in more detail as well as the suitability of innovative technologies for the implementation into such local heating networks. Here, adsorption chillers are of particular interest. By implementation of adsorption chillers, cogenerations can be expanded ecologically to trigeneration plants. In addition to the described activities, also socio-economic field studies on the heat consumers are performed in order to support the selection of technical solutions. Thereby, the research project under consideration is supported by the European Regional Development Fund (ERDF) and the Lower Saxony Ministry for Science and Culture (MWK). This research project is performed in a research consortium between

  12. Heliostat field cost reduction by `slope drive' optimization

    Science.gov (United States)

    Arbes, Florian; Weinrebe, Gerhard; Wöhrbach, Markus

    2016-05-01

    An algorithm to optimize power tower heliostat fields employing heliostats with so-called slope drives is presented. It is shown that a field using heliostats with the slope drive axes configuration has the same performance as a field with conventional azimuth-elevation tracking heliostats. Even though heliostats with the slope drive configuration have a limited tracking range, field groups of heliostats with different axes or different drives are not needed for different positions in the heliostat field. The impacts of selected parameters on a benchmark power plant (PS10 near Seville, Spain) are analyzed.

  13. Distribution Inventory Cost Optimization Under Grey and Fuzzy Uncertainty

    Institute of Scientific and Technical Information of China (English)

    LIU Dongbo; HUANG Dao; CHEN Yujuan

    2006-01-01

    The grey fuzzy variable was defined for the two fold uncertain parameters combining grey and fuzziness factors. On the basis of the credibility and chance measure of grey fuzzy variables, the distribution center inventory uncertain programming model was presented. The grey fuzzy simulation technology can generate input-output data for the uncertain functions. The neural network trained from the input-output data can approximate the uncertain functions. The designed hybrid intelligent algorithm by embedding the trained neural network into genetic algorithm can optimize the general grey fuzzy programming problems. Finally, one numerical example is provided to illustrate the effectiveness of the model and the hybrid intelligent algorithm.

  14. Sequential Optimization of Paths in Directed Graphs Relative to Different Cost Functions

    KAUST Repository

    Abubeker, Jewahir Ali

    2011-05-14

    This paper is devoted to the consideration of an algorithm for sequential optimization of paths in directed graphs relative to di_erent cost functions. The considered algorithm is based on an extension of dynamic programming which allows to represent the initial set of paths and the set of optimal paths after each application of optimization procedure in the form of a directed acyclic graph.

  15. Explicit Solution of the Average-Cost Optimality Equation for a Pest-Control Problem

    Directory of Open Access Journals (Sweden)

    Epaminondas G. Kyriakidis

    2011-01-01

    Full Text Available We introduce a Markov decision process in continuous time for the optimal control of a simple symmetrical immigration-emigration process by the introduction of total catastrophes. It is proved that a particular control-limit policy is average cost optimal within the class of all stationary policies by verifying that the relative values of this policy are the solution of the corresponding optimality equation.

  16. Heat Recovery in a Pasta Factory. Pinch Analysis Leads to Optimal Heat Pump Usage.

    OpenAIRE

    Staine, Frédéric; Favrat, Daniel; Krummenacher, Pierre

    1994-01-01

    In the previous issue of the IEA Heat Pump Centre Newsletter (Vol, 12, No.3, pp. 29-31), an article by these authors described the use of pinch analysis (also known as pinch technology) in a buildings application. This article describes a similar procedure for integrating a heat pump into a pasta production process. Many industrial processes, and particularly those dealing with drying, are characterized by an overabundance of low- grade heat which often cannot be effi...

  17. Heat Recovery in a Pasta Factory. Pinch Analysis Leads to Optimal Heat Pump Usage.

    OpenAIRE

    Staine, Frédéric; Favrat, Daniel; Krummenacher, Pierre

    1994-01-01

    In the previous issue of the IEA Heat Pump Centre Newsletter (Vol, 12, No.3, pp. 29-31), an article by these authors described the use of pinch analysis (also known as pinch technology) in a buildings application. This article describes a similar procedure for integrating a heat pump into a pasta production process. Many industrial processes, and particularly those dealing with drying, are characterized by an overabundance of low- grade heat which often cannot be effi...

  18. Optimization of multiplexed RADseq libraries using low-cost adaptors.

    Science.gov (United States)

    Henri, Hélène; Cariou, Marie; Terraz, Gabriel; Martinez, Sonia; El Filali, Adil; Veyssiere, Marine; Duret, Laurent; Charlat, Sylvain

    2015-04-01

    Reduced representation genomics approaches, of which RADseq is currently the most popular form, offer the possibility to produce genome wide data from potentially any species, without previous genomic information. The application of RADseq to highly multiplexed libraries (including numerous specimens, and potentially numerous different species) is however limited by technical constraints. First, the cost of synthesis of Illumina adaptors including molecular identifiers (MIDs) becomes excessive when numerous specimens are to be multiplexed. Second, the necessity to empirically adjust the ratio of adaptors to genomic DNA concentration impedes the high throughput application of RADseq to heterogeneous samples, of variable DNA concentration and quality. In an attempt to solve these problems, we propose here some adjustments regarding the adaptor synthesis. First, we show that the common and unique (MID) parts of adaptors can be synthesized separately and subsequently ligated, which drastically reduces the synthesis cost, and thus allows multiplexing hundreds of specimens. Second, we show that self-ligation of adaptors, which makes the adaptor concentration so critical, can be simply prevented by using unphosphorylated adaptors, which significantly improves the ligation and sequencing yield.

  19. Cost benefit theory and optimal design of gene regulation functions

    Science.gov (United States)

    Kalisky, Tomer; Dekel, Erez; Alon, Uri

    2007-12-01

    Cells respond to the environment by regulating the expression of genes according to environmental signals. The relation between the input signal level and the expression of the gene is called the gene regulation function. It is of interest to understand the shape of a gene regulation function in terms of the environment in which it has evolved and the basic constraints of biological systems. Here we address this by presenting a cost-benefit theory for gene regulation functions that takes into account temporally varying inputs in the environment and stochastic noise in the biological components. We apply this theory to the well-studied lac operon of E. coli. The present theory explains the shape of this regulation function in terms of temporal variation of the input signals, and of minimizing the deleterious effect of cell-cell variability in regulatory protein levels. We also apply the theory to understand the evolutionary tradeoffs in setting the number of regulatory proteins and for selection of feed-forward loops in genetic circuits. The present cost-benefit theory can be used to understand the shape of other gene regulatory functions in terms of environment and noise constraints.

  20. Optimal Hierarchical Decision-Making for Heat Source Selection of District Heating Systems

    Directory of Open Access Journals (Sweden)

    Fang Fang

    2014-01-01

    Full Text Available With the rapid development of China’s urbanization, the proportion between the heating consumption and the energy consumption of the whole society keeps rising in recent years. For a district heating system, the selection of the heat source makes significant impact on the energy efficiency and the pollutant emissions. By integrating the methods of the Analytic Hierarchy Process (AHP and the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE, a multiple-attribute decision-making scheme for the heat source selection of district heating systems is proposed in this paper. As a core part of this scheme, a comprehensive benefit index with hierarchical parallel structure is constructed. The economic benefit, environment benefit, and technical benefit can be reflected with a certain percentage in the comprehensive benefit index. To test the efficiency of the proposed scheme, a case study for a large-scale district heating system in Beijing is carried out, where five kinds of heat sources (water source heat pump, ground source heat pump, gas-fired boiler, coal-fired boiler, and oil-fired boiler are taken into account. The analysis and instructions for the final sorting result are also demonstrated.

  1. Optimal administrative scale for planning public services: a social cost model applied to Flemish hospital care.

    Science.gov (United States)

    Blank, Jos L T; van Hulst, Bart

    2015-01-01

    In choosing the scale of public services, such as hospitals, both economic and public administrative considerations play important roles. The scale and the corresponding spatial distribution of public institutions have consequences for social costs, defined as the institutions' operating costs and the users' travel costs (which include the money and time costs). Insight into the relationship between scale and spatial distribution and social costs provides a practical guide for the best possible administrative planning level. This article presents a purely economic model that is suitable for deriving the optimal scale for public services. The model also reveals the corresponding optimal administrative planning level from an economic perspective. We applied this model to hospital care in Flanders for three different types of care. For its application, we examined the social costs of hospital services at different levels of administrative planning. The outcomes show that the social costs of rehabilitation in Flanders with planning at the urban level (38 areas) are 11% higher than those at the provincial level (five provinces). At the regional level (18 areas), the social costs of rehabilitation are virtually equal to those at the provincial level. For radiotherapy, there is a difference of 88% in the social costs between the urban and the provincial level. For general care, there are hardly any cost differences between the three administrative levels. Thus, purely from the perspective of social costs, rehabilitation should preferably be planned at the regional level, general services at the urban level and radiotherapy at the provincial level.

  2. Optimization of radiative heat transfer in hyperbolic metamaterials for thermophotovoltaic applications.

    Science.gov (United States)

    Simovski, Constantin; Maslovski, Stanislav; Nefedov, Igor; Tretyakov, Sergei

    2013-06-17

    Using our recently developed method we analyze the radiative heat transfer in micron-thick multilayer stacks of metamaterials with hyperbolic dispersion. The metamaterials are especially designed for prospective thermophotovoltaic systems. We show that the huge transfer of near-infrared thermal radiation across micron layers of metamaterials is achievable and can be optimized. We suggest an approach to the optimal design of such metamaterials taking into account high temperatures of the emitting medium and the heating of the photovoltaic medium by the low-frequency part of the radiation spectrum. We show that both huge values and frequency selectivity are achievable for the radiative heat transfer in hyperbolic multilayer stacks.

  3. Performance Analysis and Optimization of a Solar Powered Stirling Engine with Heat Transfer Considerations

    Directory of Open Access Journals (Sweden)

    Chia-En Ho

    2012-09-01

    Full Text Available This paper investigates the optimization of the performance of a solar powered Stirling engine based on finite-time thermodynamics. Heat transference in the heat exchangers between a concentrating solar collector and the Stirling engine is studied. The irreversibility of a Stirling engine is considered with the heat transfer following Newton's law. The power generated by a Stirling engine is used as an objective function for maximum power output design with the concentrating solar collector temperature and the engine thermal efficiency as the optimization parameters. The maximum output power of engine and its corresponding system parameters are determined using a genetic algorithm.

  4. Mixed H2/H∞ Optimal Guaranteed Cost Control of Uncertain Linear Systems

    Institute of Scientific and Technical Information of China (English)

    GuodingChen; MayingYang; LiYu

    2004-01-01

    The mixed H2/H∞ guaranteed cost control problem via state feedback control laws is considered in this paper for linear systems with norm-bounded parameter uncertainty. Based on the linear matrix inequality (LMI) approach, sufficient conditions are derived for the existence of guaranteed cost controllers whihc guarantee not only a prespecified H∞ disturbance attenuation level on one controlled output for all admissible parameter uncertainties, but also the worst-case H2 performance index on the other controlled output to be no more than a specified bound. Furthermore, a convex optimization problem is formulated to design an optimal H2/H∞ guaranteed cost controller.

  5. Dynamic Portfolio Optimization with Transaction Costs and State-Dependent Drift

    DEFF Research Database (Denmark)

    Palczewski, Jan; Poulsen, Rolf; Schenk-Hoppe, Klaus Reiner

    2015-01-01

    The problem of dynamic portfolio choice with transaction costs is often addressed by constructing a Markov Chain approximation of the continuous time price processes. Using this approximation, we present an efficient numerical method to determine optimal portfolio strategies under time- and state....... It is applied to measure the value of information and the loss from transaction costs using the indifference principle.......-dependent drift and proportional transaction costs. This scenario arises when investors have behavioral biases or the actual drift is unknown and needs to be estimated. Our numerical method solves dynamic optimal portfolio problems with an exponential utility function for time-horizons of up to 40 years...

  6. Thermo-Economic and Heat Transfer Optimization of Working-Fluid Mixtures in a Low-Temperature Organic Rankine Cycle System

    Directory of Open Access Journals (Sweden)

    Oyeniyi A. Oyewunmi

    2016-06-01

    Full Text Available In the present paper, we consider the employment of working-fluid mixtures in organic Rankine cycle (ORC systems with respect to thermodynamic and heat-transfer performance, component sizing and capital costs. The selected working-fluid mixtures promise reduced exergy losses due to their non-isothermal phase-change behaviour, and thus improved cycle efficiencies and power outputs over their respective pure-fluid components. A multi-objective cost-power optimization of a specific low-temperature ORC system (operating with geothermal water at 98 °C reveals that the use of working-fluid-mixtures does indeed show a thermodynamic improvement over the pure-fluids. At the same time, heat transfer and cost analyses, however, suggest that it also requires larger evaporators, condensers and expanders; thus, the resulting ORC systems are also associated with higher costs. In particular, 50% n-pentane + 50% n-hexane and 60% R-245fa + 40% R-227ea mixtures lead to the thermodynamically optimal cycles, whereas pure n-pentane and pure R-245fa have lower plant costs, both estimated as having ∼14% lower costs per unit power output compared to the thermodynamically optimal mixtures. These conclusions highlight the importance of using system cost minimization as a design objective for ORC plants.

  7. Optimal transportation network with concave cost functions: loop analysis and algorithms.

    Science.gov (United States)

    Shao, Zhen; Zhou, Haijun

    2007-06-01

    Transportation networks play a vital role in modern societies. Structural optimization of a transportation system under a given set of constraints is an issue of great practical importance. For a general transportation system whose total cost C is determined by C = Sigma(ioptimal network topology is a tree if C(ij) proportional |I(ij)|(gamma) with 0 optimality of tree-formed networks is given. The simple intuitive picture of this proof then leads to an efficient global algorithm for the searching of optimal structures for a given transportation system with concave cost functions.

  8. Using Electromagnetic Algorithm for Total Costs of Sub-contractor Optimization in the Cellular Manufacturing Problem

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Shahriari

    2016-12-01

    Full Text Available In this paper, we present a non-linear binary programing for optimizing a specific cost in cellular manufacturing system in a controlled production condition. The system parameters are determined by the continuous distribution functions. The aim of the presented model is to optimize the total cost of imposed sub-contractors to the manufacturing system by determining how to allocate the machines and parts to each seller. In this system, DM could control the occupation level of each machine in the system. For solving the presented model, we used the electromagnetic meta-heuristic algorithm and Taguchi method for determining the optimal algorithm parameters.

  9. OPTIMAL CONTROL OF A NONLINEAR COUPLED ELECTROMAGNETIC INDUCTION HEATING SYSTEM WITH POINTWISE STATE CONSTRAINTS

    Directory of Open Access Journals (Sweden)

    Irwin Yousept

    2010-07-01

    Full Text Available An optimal control problem arising in the context of 3D electromagnetic induction heating is investigated. The state equation is given by a quasilinear stationary heat equation coupled with a semilinear time harmonic eddy current equation. The temperature-dependent electrical conductivity and the presence of pointwise inequality state-constraints represent the main challenge of the paper. In the first part of the paper, the existence and regularity of the state are addressed. The second part of the paper deals with the analysis of the corresponding linearized equation. Some suffcient conditions are presented which guarantee thesolvability of the linearized system. The final part of the paper is concerned with the optimal control. The aim of the optimization is to find the optimal voltage such that a desired temperature can be achieved optimally. The corresponding first-order necessary optimality condition is presented.

  10. The environmental cost of subsistence: Optimizing diets to minimize footprints

    Energy Technology Data Exchange (ETDEWEB)

    Gephart, Jessica A.; Davis, Kyle F. [University of Virginia, Department of Environmental Sciences, 291 McCormick Road, Charlottesville, VA 22904 (United States); Emery, Kyle A. [University of Virginia, Department of Environmental Sciences, 291 McCormick Road, Charlottesville, VA 22904 (United States); University of California, Santa Barbara. Marine Science Institute, Santa Barbara, CA 93106 (United States); Leach, Allison M. [University of New Hampshire, 107 Nesmith Hall, 131 Main Street, Durham, NH, 03824 (United States); Galloway, James N.; Pace, Michael L. [University of Virginia, Department of Environmental Sciences, 291 McCormick Road, Charlottesville, VA 22904 (United States)

    2016-05-15

    The question of how to minimize monetary cost while meeting basic nutrient requirements (a subsistence diet) was posed by George Stigler in 1945. The problem, known as Stigler's diet problem, was famously solved using the simplex algorithm. Today, we are not only concerned with the monetary cost of food, but also the environmental cost. Efforts to quantify environmental impacts led to the development of footprint (FP) indicators. The environmental footprints of food production span multiple dimensions, including greenhouse gas emissions (carbon footprint), nitrogen release (nitrogen footprint), water use (blue and green water footprint) and land use (land footprint), and a diet minimizing one of these impacts could result in higher impacts in another dimension. In this study based on nutritional and population data for the United States, we identify diets that minimize each of these four footprints subject to nutrient constraints. We then calculate tradeoffs by taking the composition of each footprint's minimum diet and calculating the other three footprints. We find that diets for the minimized footprints tend to be similar for the four footprints, suggesting there are generally synergies, rather than tradeoffs, among low footprint diets. Plant-based food and seafood (fish and other aquatic foods) commonly appear in minimized diets and tend to most efficiently supply macronutrients and micronutrients, respectively. Livestock products rarely appear in minimized diets, suggesting these foods tend to be less efficient from an environmental perspective, even when nutrient content is considered. The results' emphasis on seafood is complicated by the environmental impacts of aquaculture versus capture fisheries, increasing in aquaculture, and shifting compositions of aquaculture feeds. While this analysis does not make specific diet recommendations, our approach demonstrates potential environmental synergies of plant- and seafood-based diets. As a result

  11. Study on Engineering Design and Cost Performance of Borehole Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Lei Yu

    2015-01-01

    Full Text Available The ground source heat pump (GSHP is an environmentally friendly and energy-efficient technology, and the investigations on the simulation models of borehole heat exchanger (BHE have made progress. However, the researches on engineering design and economic performance based on the simulation models of BHE are a few. This paper firstly describes the interior and exterior heat transfer according to the existing achievements, and the corresponding characteristics of models are explained. Afterwards, the detailed design procedures of BHE size are provided and the cost performance is highlighted. Accordingly, an actual engineering project which employs GSHP system as the air conditioning system is researched; the necessary expenses on BHE, heat pump units, and indoor end equipment are all taken into account. The initial investment, operating cost, and other factors that exert influences on the cost performance are demonstrated. In addition, comparisons between different systems are conducted to show the advantages of GSHP. By means of thermal transfer analysis and the design of engineering project, the practicability, energy saving, and environmental protection of GSHP are brought into play, which means the promotion of this technology is the general trend of development of air condition system.

  12. Optimal phasing of district heating network investments using multi-stage stochastic programming

    Directory of Open Access Journals (Sweden)

    Romain Stephane Claude Lambert

    2016-06-01

    Full Text Available Most design optimisation studies for district heating systems have focused on the optimal sizing of network assets and on the location of production units. However, the strategic value of the flexibility in phasing of the inherently modular heat networks, which is an important aspect in many feasibility studies for district heating schemes in the UK, is almost always neglected in the scientific literature. This paper considers the sequential problem faced by a decision-maker in the phasing of long-term investments into district heating networks and their expansions. The problem is formulated as a multi-stage stochastic programme to determine the annual capital expenditure that maximises the expected net present value of the project. The optimisation approach is illustrated by applying it to the hypothetical case of the UK’s Marston Vale eco town. It was found that the approach is capable of simulating the optimal growth of a network, from both a single heat source or separate islands of growth, as well as the optimal marginal expansion of an existing district heating network. The proposed approach can be used by decision makers as a framework to determine both the optimal phasing and extension of district heating networks and can be adapted simply to various, more complex real-life situations by introducing additional constraints and parameters. The versatility of the base formulation also makes it a powerful approach regardless of the size of the network and also potentially applicable to cooling networks.

  13. Commitment and dispatch of heat and power units via affinely adjustable robust optimization

    DEFF Research Database (Denmark)

    Zugno, Marco; Morales González, Juan Miguel; Madsen, Henrik

    2016-01-01

    The joint management of heat and power systems is believed to be key to the integration of renewables into energy systems with a large penetration of district heating. Determining the day-ahead unit commitment and production schedules for these systems is an optimization problem subject...... to uncertainty stemming from the unpredictability of demand and prices for heat and electricity. Furthermore, owing to the dynamic features of production and heat storage units as well as to the length and granularity of the optimization horizon (e.g., one whole day with hourly resolution), this problem...... approach. Secondly, we appraise the gain obtained by switching from linear to piecewise-linear decision rules within robust optimization. Furthermore, we give directions for selecting the parameters defining the uncertainty set (size, budget) and assess the resulting trade-off between average profit...

  14. Optimal paths for a light-driven engine with a linear phenomenological heat transfer law

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    An irreversible light-driven engine is described in this paper, in which the heat transfer between the working fluid and the environment obeys a linear phenomenological heat transfer law [ q ∝Δ(T -1)], with a working fluid composed of the bimolecular reacting system 2SO 3 F■S 2 O 6 F2. Piston trajectories maximizing work output and minimizing entropy generation are determined for such an engine with rate-dependent loss mechanisms of friction and heat leakage. The optimal control theory is applied to determine the optimal configurations of the piston motion trajectory and the fluid temperature. Numerical examples for the optimal configuration are provided, and the obtained results are compared with those derived with Newtonian heat transfer law [ q ∝Δ(T )].

  15. Entransy and Exergy Analyses for Optimizations of Heat-Work Conversion with Carnot Cycle

    Institute of Scientific and Technical Information of China (English)

    Chul Ho Han; Kyoung Hoon Kim

    2016-01-01

    The concept of entransy has been newly proposed in terms of the analogy between heat and electrical conduction and could be useful in analyzing and optimizing the heat-work conversion systems.This work presents comparative analyses of entransy and exergy for optimizations of heat-work conversion.The work production and heat transfer processes in Carnot cycle system are investigated with the formulations of exergy destruction,entransy loss,work entransy,entransy dissipation,and efficiencies for both cases of dumping and non-dumping of used source fluid.The effects of source and condensation temperatures on the system performance are systematically investigated for optimal condition of producing maximum work or work entransy.

  16. The Optimal Sequence of Production Orders, Taking into Account the Cost of Delays

    Directory of Open Access Journals (Sweden)

    Dylewski Robert

    2016-06-01

    Full Text Available In flexible manufacturing systems the most important element in determining the proper course of technological processes, transport and storage is the control and planning subsystem. The key planning task is to determine the optimal sequence of production orders. This paper proposes a new method of determining the optimal sequence of production orders in view of the sum of the costs related to the delayed execution of orders. It takes into account the different unit costs of delays of individual orders and the amount of allowable delays of orders involving no delay costs. The optimum sequence of orders, in the single-machine problem, in view of the sum of the costs of delays may be significantly different from the optimal order, taking into account the sum of delay times.

  17. Cost Optimization for Series-Parallel Petroleum Transportation Pape-Lines under Reliability Constraints

    Directory of Open Access Journals (Sweden)

    M. Amara,

    2014-01-01

    Full Text Available This paper uses an ant colony meta-heuristic optimization method to solve the cost-optimization problem in petrolum industry. This problem is known as total investment-cost minimization of series-parallel transportation pape lines. Redundant Electro-Pumpe coupled to the papes lines are included to achieve a desired level of availability. System availability is represented by a multi-state availability function. The Electro-pumpe (pape-lines are characterized by their capacity, availability and cost. These electro-pumpes are chosen among a list of products available on the market. The proposed meta-heuristic seeks to find the best minimal cost of petrol transportation system configuration with desired availability. To estimate the series-parallel pape lines availability, a fast method based on universal moment generating function (UMGF is suggested. The ant colony approach is used as an optimization technique. An example of petrol transportation system is presented.

  18. Industrial Application of Topology Optimization for Combined Conductive and Convective Heat Transfer Problems

    DEFF Research Database (Denmark)

    Zhou, Mingdong; Alexandersen, Joe; Sigmund, Ole

    2016-01-01

    This paper presents an industrial application of topology optimization for combined conductive and convective heat transfer problems. The solution is based on a synergy of computer aided design and engineering software tools from Dassault Systemes. The considered physical problem of steady......-state heat transfer under convection is simulated using SIMULIA-Abaqus. A corresponding topology optimization feature is provided by SIMULIA-Tosca. By following a standard workflow of design optimization, the proposed solution is able to accommodate practical design scenarios and results in efficient...

  19. Optimal and maximin sample sizes for multicentre cost-effectiveness trials.

    Science.gov (United States)

    Manju, Md Abu; Candel, Math J J M; Berger, Martijn P F

    2015-10-01

    This paper deals with the optimal sample sizes for a multicentre trial in which the cost-effectiveness of two treatments in terms of net monetary benefit is studied. A bivariate random-effects model, with the treatment-by-centre interaction effect being random and the main effect of centres fixed or random, is assumed to describe both costs and effects. The optimal sample sizes concern the number of centres and the number of individuals per centre in each of the treatment conditions. These numbers maximize the efficiency or power for given research costs or minimize the research costs at a desired level of efficiency or power. Information on model parameters and sampling costs are required to calculate these optimal sample sizes. In case of limited information on relevant model parameters, sample size formulas are derived for so-called maximin sample sizes which guarantee a power level at the lowest study costs. Four different maximin sample sizes are derived based on the signs of the lower bounds of two model parameters, with one case being worst compared to others. We numerically evaluate the efficiency of the worst case instead of using others. Finally, an expression is derived for calculating optimal and maximin sample sizes that yield sufficient power to test the cost-effectiveness of two treatments. © The Author(s) 2015.

  20. Simulation and Optimization of the Heat Exchanger for Automotive Exhaust-Based Thermoelectric Generators

    Science.gov (United States)

    Su, C. Q.; Huang, C.; Deng, Y. D.; Wang, Y. P.; Chu, P. Q.; Zheng, S. J.

    2016-03-01

    In order to enhance the exhaust waste heat recovery efficiency of the automotive exhaust-based thermoelectric generator (TEG) system, a three-segment heat exchanger with folded-shaped internal structure for the TEG system is investigated in this study. As the major effect factors of the performance for the TEG system, surface temperature, and thermal uniformity of the heat exchanger are analyzed in this research, pressure drop along the heat exchanger is also considered. Based on computational fluid dynamics simulations and temperature distribution, the pressure drop along the heat exchanger is obtained. By considering variable length and thickness of folded plates in each segment of the heat exchanger, response surface methodology and optimization by a multi-objective genetic algorithm is applied for surface temperature, thermal uniformity, and pressure drop for the folded-shaped heat exchanger. An optimum design based on the optimization is proposed to improve the overall performance of the TEG system. The performance of the optimized heat exchanger in different engine conditions is discussed.

  1. Simultaneous optimization of heat-integrated crude oil distillation systems☆

    Institute of Scientific and Technical Information of China (English)

    Yiqing Luo; Liwen Wang; He Wang; Xigang Yuan

    2015-01-01

    Crude oil distil ation is important in refining industry. Operating variables of distil ation process have a critical ef-fect on product output value and energy consumption. However, the objectives of minimum energy consumption and maximum product output value do not coordinate with each other and do not lead to the maximum eco-nomic benefit of a refinery. In this paper, a systematic optimization approach is proposed for the maximum an-nual economic benefit of an existing crude oil distil ation system, considering product output value and energy consumption simultaneously. A shortcut model in Aspen Plus is used to describe the crude oil distillation and the pinch analysis is adopted to identify the target of energy recovery. The optimization is a nonlinear program-ming problem and solved by stochastic algorithm of particle warm optimization.

  2. Modeling the lowest-cost splitting of a herd of cows by optimizing a cost function

    OpenAIRE

    Gajamannage, Kelum; Bollt, Erik M; Porter, Mason A.; Dawkins, Marian S.

    2016-01-01

    Animals live in groups to defend against predation and to obtain food. However, for some animals --- especially ones that spend long periods of time feeding --- there are costs if a group chooses to move on before their nutritional needs are satisfied. If the conflict between feeding and keeping up with a group becomes too large, it may be advantageous to some animals to split into subgroups of animals with similar nutritional needs. We model the costs and benefits of splitting by a herd of c...

  3. Diet-dependent heat emission reveals costs of post-diapause recovery from different nutritional sources in a carnivorous beetle

    Science.gov (United States)

    Toft, Søren; Nielsen, Søren Achim

    2017-08-01

    Restoration of fat stores is metabolic first priority for many insects that emerge from hibernation with depleted fat bodies. To some extent, the animals must be flexible and use whatever foods available irrespective of their nutrient composition. Previously, the carabid beetles Anchomenus dorsalis have been found to refill their fat stores to the same extent over 9 days irrespective of the nutrient composition of their food. However, a higher cost of fat deposition when the food was rich in sugar or protein rather than lipid was indicated by higher total energy consumption. Here, we test the hypothesis of increased metabolic costs of building fat stores from sugar- or protein-rich food than from lipid-rich food by microcalorimetry. We measured the heat emitted from beetles that had fed on sugar-, protein-, or lipid-rich food for 0 (common control), 2, 5, or 10 days. As predicted, heat emission was increased in beetles getting sugar- and protein-rich food compared with those getting lipid-rich food. However, we did not confirm the beetles' ability to rebuild fat stores from protein-rich food; instead, they increased in lean mass. Overall, sugar-rich food seems to be optimal for post-winter recovery, because it is better than lipid-rich food that allows concurrent rebuilding of fat stores and lean mass, which may benefit preparation for spring migration and reproduction. We propose that overwintered fruits may be highly preferred post-diapause food for these otherwise mostly carnivorous beetles.

  4. Comparative Analysis of Selected Factors Affecting Heating Costs of Schools in Selected Balkan Countries

    Directory of Open Access Journals (Sweden)

    Koppitz David

    2015-06-01

    Full Text Available The paper aims to carry out a comparative analysis of heating of school facilities under the administration of municipalities in Macedonia, Moldova and Kosovo and to test the factors that affect the heating costs of school facilities. For a definition of the theoretical fundament parts of the theory of fiscal federalism are used. Subsequently five hypotheses are put forward that are verified using the method of benchmarking. The theoretical conclusions and recommendations may be used for a more effective implementation of public policies within the surveyed countries.

  5. Cost Saving Opportunities in NSCLC Therapy by Optimized Diagnostics

    Directory of Open Access Journals (Sweden)

    Ilija Nenadić

    2017-07-01

    Full Text Available With an incidence of 68 new cases per 100,000 people per year, an estimated total number of up to 350,000 new non-small-cell lung cancer (NSCLC cases are diagnosed each year in the European Union. Up to 10% of NSCLC patients are eligible for therapy with novel ALK (anaplastic lymphoma kinase inhibitors, as they have been diagnosed with a mutation in the gene coding for ALK. The ALK inhibitor therapy costs add up to approx. 9,000 € per patient per month, with treatment durations of up to one year. Recent studies have shown that up to 10% of ALK cases are misdiagnosed by nearly 40% of pathologic investigations. The current state-of-the-art ALK diagnostic procedure comprises a Fluorescent in situ Hybridization (FISH assay accompanied by ALK inhibitor therapy (Crizotinib. The therapy success ranges between a full therapy failure and the complete remission of the tumor (i.e., healing, but the biomedical and systemic reasons for this range remain unknown so far. It appears that the variety of different ALK mutations and variants contributes to the discrepancy in therapy results. Although the major known fusion partner for ALK in NSCLC is the Echinoderm microtubule-associated protein-like 4 (EML4, of which a minimum of 15 variants have been described, an additional 20 further ALK fusion variants with other genes are known, of which three have already been found in NSCLC. We hypothesize that the wide variety of known (and unknown ALK mutations is associated with a variable therapy success, thus rendering current companion diagnostic procedures (FISH and therapy (Crizotinib only partly applicable in ALK-related NSCLC treatment. In cell culture, differing sensitivity to Crizotinib has been shown for some fusion variants, but it is as yet unknown which of them are really biologically active in cancer patients, and how the respective variants affect the response to Crizotinib treatment. Moreover, it has been demonstrated that translocated ALK genes can

  6. Optimal actuator location of minimum norm controls for heat equation with general controlled domain

    Science.gov (United States)

    Guo, Bao-Zhu; Xu, Yashan; Yang, Dong-Hui

    2016-09-01

    In this paper, we study optimal actuator location of the minimum norm controls for a multi-dimensional heat equation with control defined in the space L2 (Ω × (0 , T)). The actuator domain is time-varying in the sense that it is only required to have a prescribed Lebesgue measure for any moment. We select an optimal actuator location so that the optimal control takes its minimal norm over all possible actuator domains. We build a framework of finding the Nash equilibrium so that we can develop a sufficient and necessary condition to characterize the optimal relaxed solutions for both actuator location and corresponding optimal control of the open-loop system. The existence and uniqueness of the optimal classical solutions are therefore concluded. As a result, we synthesize both optimal actuator location and corresponding optimal control into a time-varying feedbacks.

  7. An optimality criterion for sizing members of heated structures with temperature constraints. [considering aerospace structures

    Science.gov (United States)

    Rao, G. V.; Shore, C. P.; Narayanaswami, R.

    1977-01-01

    A thermal optimality criterion is presented for sizing members of heated structures with multiple temperature constraints. The optimality criterion is similar to an existing optimality criterion for design of mechanically loaded structures with displacement constraints. Effectiveness of the thermal optimality criterion is assessed by applying it to one- and two-dimensional thermal problems where temperatures can be controlled by varying the material distribution in the structure. Results obtained from the optimality criterion agree within 2 percent with results from a closed-form solution and with results from a mathematical programming technique. The thermal optimality criterion augments existing optimality criteria for strength and stiffness related constraints and offers the possibility of extension of optimality techniques to sizing structures with combined thermal and mechanical loading.

  8. Multi-objective optimization approach for cost management during product design at the conceptual phase

    Science.gov (United States)

    Durga Prasad, K. G.; Venkata Subbaiah, K.; Narayana Rao, K.

    2014-03-01

    The effective cost management during the conceptual design phase of a product is essential to develop a product with minimum cost and desired quality. The integration of the methodologies of quality function deployment (QFD), value engineering (VE) and target costing (TC) could be applied to the continuous improvement of any product during product development. To optimize customer satisfaction and total cost of a product, a mathematical model is established in this paper. This model integrates QFD, VE and TC under multi-objective optimization frame work. A case study on domestic refrigerator is presented to show the performance of the proposed model. Goal programming is adopted to attain the goals of maximum customer satisfaction and minimum cost of the product.

  9. Optimal Control of Residential Heating and Cooling Systems.

    Science.gov (United States)

    1982-01-01

    best possible. The question of optimal flow control versus several different bang-bang flow controls was addressed by Piessens, et al. [13). Using TRNSYS ...most 113 simulation programs, for example, TRNSYS [ 15]. For an air collector, however, the collector efficiency factor may not be constant

  10. Cost optimal building performance requirements. Calculation methodology for reporting on national energy performance requirements on the basis of cost optimality within the framework of the EPBD

    Energy Technology Data Exchange (ETDEWEB)

    Boermans, T.; Bettgenhaeuser, K.; Hermelink, A.; Schimschar, S. [Ecofys, Utrecht (Netherlands)

    2011-05-15

    On the European level, the principles for the requirements for the energy performance of buildings are set by the Energy Performance of Buildings Directive (EPBD). Dating from December 2002, the EPBD has set a common framework from which the individual Member States in the EU developed or adapted their individual national regulations. The EPBD in 2008 and 2009 underwent a recast procedure, with final political agreement having been reached in November 2009. The new Directive was then formally adopted on May 19, 2010. Among other clarifications and new provisions, the EPBD recast introduces a benchmarking mechanism for national energy performance requirements for the purpose of determining cost-optimal levels to be used by Member States for comparing and setting these requirements. The previous EPBD set out a general framework to assess the energy performance of buildings and required Member States to define maximum values for energy delivered to meet the energy demand associated with the standardised use of the building. However it did not contain requirements or guidance related to the ambition level of such requirements. As a consequence, building regulations in the various Member States have been developed by the use of different approaches (influenced by different building traditions, political processes and individual market conditions) and resulted in different ambition levels where in many cases cost optimality principles could justify higher ambitions. The EPBD recast now requests that Member States shall ensure that minimum energy performance requirements for buildings are set 'with a view to achieving cost-optimal levels'. The cost optimum level shall be calculated in accordance with a comparative methodology. The objective of this report is to contribute to the ongoing discussion in Europe around the details of such a methodology by describing possible details on how to calculate cost optimal levels and pointing towards important factors and

  11. Residential heating costs: a comparison of geothermal, solar and conventional resources

    Energy Technology Data Exchange (ETDEWEB)

    Bloomster, C.H.; Garrett-Price, B.A.; Fassbender, L.L.

    1980-08-01

    The costs of residential heating throughout the United States using conventional, solar, and geothermal energy were determined under current and projected conditions. These costs are very sensitive to location - being dependent on the local prices of conventional energy supplies, local solar insolation, cimate, and the proximity and temperature of potential geothermal resources. The sharp price increases in imported fuels during 1979 and the planned decontrol of domestic oil and natural gas prices have set the stage for geothermal and solar market penetration in the 1980's.

  12. A bivariate optimal replacement policy with cumulative repair cost limit under cumulative damage model

    Indian Academy of Sciences (India)

    MIN-T SAI LAI; SHIH-CHIH CHEN

    2016-05-01

    In this paper, a bivariate replacement policy (n, T) for a cumulative shock damage process is presented that included the concept of cumulative repair cost limit. The arrival shocks can be divided into two kinds of shocks. Each type-I shock causes a random amount of damage and these damages are additive. When the total damage exceeds a failure level, the system goes into serious failure. Type-II shock causes the system into minor failure and such a failure can be corrected by minimal repair. When a minor failure occurs, the repaircost will be evaluated and minimal repair is executed if the accumulated repair cost is less than a predetermined limit L. The system is replaced at scheduled time T, at n-th minor failure, or at serious failure. The long-term expected cost per unit time is derived using the expected costs as the optimality criterion. The minimum-cost policy is derived, and existence and uniqueness of the optimal n* and T* are proved. This bivariate optimal replacement policy (n, T) is showed to be better than the optimal T* and the optimal n* policy.

  13. Optimal design of green and grey stormwater infrastructure for small urban catchment based on life-cycle cost-effectiveness analysis

    Science.gov (United States)

    Yang, Y.; Chui, T. F. M.

    2016-12-01

    Green infrastructure (GI) is identified as sustainable and environmentally friendly alternatives to the conventional grey stormwater infrastructure. Commonly used GI (e.g. green roof, bioretention, porous pavement) can provide multifunctional benefits, e.g. mitigation of urban heat island effects, improvements in air quality. Therefore, to optimize the design of GI and grey drainage infrastructure, it is essential to account for their benefits together with the costs. In this study, a comprehensive simulation-optimization modelling framework that considers the economic and hydro-environmental aspects of GI and grey infrastructure for small urban catchment applications is developed. Several modelling tools (i.e., EPA SWMM model, the WERF BMP and LID Whole Life Cycle Cost Modelling Tools) and optimization solvers are coupled together to assess the life-cycle cost-effectiveness of GI and grey infrastructure, and to further develop optimal stormwater drainage solutions. A typical residential lot in New York City is examined as a case study. The life-cycle cost-effectiveness of various GI and grey infrastructure are first examined at different investment levels. The results together with the catchment parameters are then provided to the optimization solvers, to derive the optimal investment and contributing area of each type of the stormwater controls. The relationship between the investment and optimized environmental benefit is found to be nonlinear. The optimized drainage solutions demonstrate that grey infrastructure is preferred at low total investments while more GI should be adopted at high investments. The sensitivity of the optimized solutions to the prices the stormwater controls is evaluated and is found to be highly associated with their utilizations in the base optimization case. The overall simulation-optimization framework can be easily applied to other sites world-wide, and to be further developed into powerful decision support systems.

  14. Optimal Operation of Network-Connected Combined Heat and Powers for Customer Profit Maximization

    Directory of Open Access Journals (Sweden)

    Da Xie

    2016-06-01

    Full Text Available Network-connected combined heat and powers (CHPs, owned by a community, can export surplus heat and electricity to corresponding heat and electric networks after community loads are satisfied. This paper proposes a new optimization model for network-connected CHP operation. Both CHPs’ overall efficiency and heat to electricity ratio (HTER are assumed to vary with loading levels. Based on different energy flow scenarios where heat and electricity are exported to the network from the community or imported, four profit models are established accordingly. They reflect the different relationships between CHP energy supply and community load demand across time. A discrete optimization model is then developed to maximize the profit for the community. The models are derived from the intervals determined by the daily operation modes of CHP and real-time buying and selling prices of heat, electricity and natural gas. By demonstrating the proposed models on a 1 MW network-connected CHP, results show that the community profits are maximized in energy markets. Thus, the proposed optimization approach can help customers to devise optimal CHP operating strategies for maximizing benefits.

  15. Optimization of Low-Temperature Exhaust Gas Waste Heat Fueled Organic Rankine Cycle

    Institute of Scientific and Technical Information of China (English)

    WANGHui—tao; WANGHua; ZHANGZhu—ming

    2012-01-01

    Low temperature exhaust gases carrying large amount of waste heat are released by steel-making process and many other industries, Organic Rankine Cycles (ORCs) are proven to be the most promising technology to re- cover the low-temperature waste heat, thereby to get more financial benefits for these industries. The exergy analysis of ORC units driven by low-temperature exhaust gas waste heat and charged with dry and isentropic fluid was per- formed, and an intuitive approach with simple impressions was developed to calculate the performances of the ORC unit. Parameter optimization was conducted with turbine inlet temperature simplified as the variable and exergy effi- ciency or power output as the objective function by means of Penalty Function and Golden Section Searching algo- rithm based on the formulation of the optimization problem. The power generated by the optimized ORC unit can be nearly as twice as that generated by a non-optimized ORC unit. In addition, cycle parametric analysis was performed to examine the effects of thermodynamic parameters on the cycle performances such as thermal efficiency and exergy efficiency. It is proven that performance of ORC unit is mainly affected by the thermodynamic property of working fluid, the waste heat temperature, the pinch point temperature of the evaporator, the specific heat capacity of the heat carrier and the turbine inlet temperature under a given environment temperature.

  16. Impact of different national biomass policies on investment costs of biomass district heating plants. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-04-01

    The BIO-COST project - co-ordinated by E.V.A. - was funded by the European Commission's THERMIE Type B Programme. The objective of BIO-COST was to analyse the impact of national biomass policies on the investment costs of biomass district heating (DH) plants. The European comparison should help identifying measures to reduce investment costs for biomass DH plants and/or components down to a 'best practice' level. The investigation is based on the comparison of 20 biomass DH plants by country, with Denmark and Sweden having mainly high energy taxes as driver, while Austria and France rely mainly on subsidy systems. The results of BIO-COST show, that governmental policies can have a big impact especially on grid and buildings costs, effecting of course the overall costs of the plant enormously. Emission standards have their effects especially on the costs for technical equipment, however, this fact was not reflected in the BIO-COST data. The results do not show a clear advantage of either the energy tax approach or the subsidy approach: The French subsidy approach leads to fairly low cost levels compared to the Danish tax approach, while the Swedish tax approach seems to yield the lowest cost level. On the other hand the Austrian subsidy approach seems to intercrease investment costs. In principle both the tax as the subsidy approach can lead to the same effect: a project is calculated in such a way, that it just meets economic breakeven. This is typically the case when the project is not carried out by a private enterprise but by an operator aiming at enhanced public welfare (e.g. co-operative, municipality). In this case a subsidy model might yield more possibilities to encourage an economically efficient development, than a tax. Instead of giving subsidies as a fixed percentage of investments they could be adjusted to the actual needs of the project as proven by a standardised calculation. Of course this can create the incentive to expect higher

  17. Heating Water with Solar Energy Costs Less at the Phoenix Federal Correctional Institution

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-09-01

    A large solar thermal system installed at the Phoenix Federal Correctional Institution (FCI) in 1998 heats water for the prison and costs less than buying electricity to heat that water. This renewable energy system provides 70% of the facility's annual hot water needs. The Federal Bureau of Prisons did not incur the up-front cost of this system because it was financed through an Energy Savings Performance Contract (ESPC). The ESPC payments are 10% less than the energy savings so that the prison saves an average of $6,700 per year, providing an immediate payback. The solar hot water system produces up to 50,000 gallons of hot water daily, enough to meet the needs of 1,250 inmates and staff who use the kitchen, shower, and laundry facilities. This publication details specifications of the parabolic trough solar system and highlights 5 years of measured performance data.

  18. Optimization of a Low Heat Load Turbine Nozzle Guide Vane

    Science.gov (United States)

    2006-03-01

    by Durbin et al. [31] to define optimally contoured endwalls for a one-blade, two-passage infinite cascade for turbulence modeling studies...Baldin-Lomax algebraic turbulence model. The code grid zones included two overset grids, an O and an H grid. The grids are used to make the...1984, pp. 173-182. [31] Durbin , P., Eaton, J., Laskowski, G., and Vicharelli, A., “Transonic Cascade Measurements to Support Turbulence Modeling

  19. Power density analysis and optimization of a regenerated closed variable-temperature heat reservoir Brayton cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lingen Chen; Junlin Zheng; Fengrui Sun [Naval University of Engineering, Wuhan (China). Faculty 306; Chih Wu [US Naval Academy, Annapolis, MD (United States). Mechanical Engineering Dept.

    2001-06-07

    In this paper, the power density, defined as the ratio of power output to the maximum specific volume in the cycle, is taken as the objective for performance analysis and optimization of an irreversible regenerated closed Brayton cycle coupled to variable-temperature heat reservoirs from the viewpoint of finite time thermodynamics (FTT) or entropy generation minimization (EGM). The analytical formulae about the relations between power density and pressure ratio are derived with the heat resistance losses in the hot- and cold-side heat exchangers and the regenerator, the irreversible compression and expansion losses in the compressor and turbine, the pressure drop losses at the heater, cooler and regenerator as well as in the piping, and the effect of the finite thermal capacity rate of the heat reservoirs. The obtained results are compared with those results obtained by using the maximum power criterion, and the advantages and disadvantages of maximum power density design are analysed. The maximum power density optimization is performed in two stages. The first is to search the optimum beat conductance distribution corresponding to the optimum power density among the hot- and cold-side heat exchangers and the regenerator for a fixed total heat exchanger inventory. The second is to search the optimum thermal capacitance rate matching corresponding to the optimum power density between the working fluid and the high-temperature heat source for a fixed ratio of the thermal capacitance rates of two heat reservoirs. The influences of some design parameters, including the effectiveness of the regenerator, the inlet temperature ratio of the heat reservoirs, the effectiveness of the heat exchangers between the working fluid and the heat reservoirs, the efficiencies of the compressor and the turbine, and the pressure recovery coefficient, on the optimum heat conductance distribution, the optimum thermal capacitance rate matching, and the maximum power density are provided by

  20. Heat Transfer Analysis for Optimal Design of Radioisotope Thermoelectric Generator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Han; Son, Kwang Jae; Hong, Jintae; Kim, Jong Bum [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    A new approach is need in the space development and requires a technique having a high degree of reliability. For example, there is radioisotope thermoelectric generator(RTG) using radioisotope that has different mechanism in comparison with solar power as power source. This is a technology that has already been trusted by generator for space in the developed countries. For example, RTG is essential for moon explorer because no other power exist source night of moon. In this study, we investigated the thermal efficiency according to the structure of RTG. Specifically, the thermal properties were analyzed according to the presence of the shield inside vacuum heat-insulating part of the RTG through the finite element analysis. Finite element analysis was used to analyze the characteristics of the temperature distribution in the RTG models according to the shield. The structure of the shield came out less heat loss than the structure without shield. As a result, the structure with a shield is advantage in the RTG design.

  1. Application of particle swarm optimization technique for optimal location of FACTS devices considering cost of installation and system loadability

    Energy Technology Data Exchange (ETDEWEB)

    Saravanan, M.; Slochanal, S. Mary Raja; Venkatesh, P.; Abraham, J. Prince Stephen [Electrical and Electronics Engineering Department, Thiagarajar College of Engineering, Madurai 625015 (India)

    2007-03-15

    This paper presents the application of particle swarm optimization (PSO) technique to find the optimal location of flexible AC transmission system (FACTS) devices with minimum cost of installation of FACTS devices and to improve system loadability (SL). While finding the optimal location, thermal limit for the lines and voltage limit for the buses are taken as constraints. Three types of FACTS devices, thyristor controlled series compensator (TCSC), static VAR compensator (SVC) and unified power flow controller (UPFC) are considered. The optimizations are performed on the parameters namely the location of FACTS devices, their setting, their type, and installation cost of FACTS devices. Two cases namely, single-type devices (same type of FACTS devices) and multi-type devices (combination of TCSC, SVC and UPFC) are considered. Simulations are performed on IEEE 6, 30 and 118 bus systems and Tamil Nadu Electricity Board (TNEB) 69 bus system, a practical system in India for optimal location of FACTS devices. The results obtained are quite encouraging and will be useful in electrical restructuring. (author)

  2. Nonlinear Dissipation Heat Devices in Finite-Time Thermodynamics: An Analysis of the Trade-Off Optimization

    Science.gov (United States)

    Lu, Can-can; Bai, Long

    2017-06-01

    The nonlinear dissipation heat devices are proposed by means of generalizing the low-dissipation heat devices to the quadratic order case. The dimensionless formulas of the output (input) power and the efficiency (coefficient of performance) for the nonlinear dissipation heat engines (refrigerators) are derived in terms of characteristic parameters for heat devices and the dimensional analysis. Based on the trade-off criterion, the optimal performance of the nonlinear dissipation heat devices is discussed in depth, and some system-specific properties for the nonlinear dissipation heat devices under the trade-off optimization are also uncovered. Our results may provide practical insight for designing actual heat engines and refrigerators.

  3. Vertical and lateral flight optimization algorithm and missed approach cost calculation

    Science.gov (United States)

    Murrieta Mendoza, Alejandro

    Flight trajectory optimization is being looked as a way of reducing flight costs, fuel burned and emissions generated by the fuel consumption. The objective of this work is to find the optimal trajectory between two points. To find the optimal trajectory, the parameters of weight, cost index, initial coordinates, and meteorological conditions along the route are provided to the algorithm. This algorithm finds the trajectory where the global cost is the most economical. The global cost is a compromise between fuel burned and flight time, this is determined using a cost index that assigns a cost in terms of fuel to the flight time. The optimization is achieved by calculating a candidate optimal cruise trajectory profile from all the combinations available in the aircraft performance database. With this cruise candidate profile, more cruises profiles are calculated taken into account the climb and descend costs. During cruise, step climbs are evaluated to optimize the trajectory. The different trajectories are compared and the most economical one is defined as the optimal vertical navigation profile. From the optimal vertical navigation profile, different lateral routes are tested. Taking advantage of the meteorological influence, the algorithm looks for the lateral navigation trajectory where the global cost is the most economical. That route is then selected as the optimal lateral navigation profile. The meteorological data was obtained from environment Canada. The new way of obtaining data from the grid from environment Canada proposed in this work resulted in an important computation time reduction compared against other methods such as bilinear interpolation. The algorithm developed here was evaluated in two different aircraft: the Lockheed L-1011 and the Sukhoi Russian regional jet. The algorithm was developed in MATLAB, and the validation was performed using Flight-Sim by Presagis and the FMS CMA-9000 by CMC Electronics -- Esterline. At the end of this work a

  4. Cost of electricity from small scale co-generation of electricity and heat

    Energy Technology Data Exchange (ETDEWEB)

    Kjellstroem, Bjoern

    2012-07-15

    There is an increasing interest in Sweden for using also small heat loads for cogeneration of electricity and heat. Increased use of small CHP-plants with heat supply capacities from a few 100 kW(h) up to 10 MW(h) cannot change the structure of the electricity supply system significantly, but could give an important contribution of 2 - 6 TWh(e) annually. The objective of this study was to clarify under what conditions electricity can be generated in small wood fired CHP-plants in Sweden at costs that can compete with those for plants using fossil fuels or nuclear energy. The capacity range studied was 2 - 10 MW(h). The results should facilitate decisions about the meaningfulness of considering CHP as an option when new heat supply systems for small communities or sawmills are planned. At the price for green certificates in Sweden, 250 - 300 SEK/MWh(e), generation costs in small wood fired CHP-plants should be below about 775 SEK/MWh(e) to compete with new nuclear power plants and below about 925 SEK/MWh(e) to compete with generation using fossil fuels.

  5. An Environmental and Economic Assessment for Selecting the Optimal Ground Heat Exchanger by Considering the Entering Water Temperature

    Directory of Open Access Journals (Sweden)

    Jimin Kim

    2015-07-01

    Full Text Available In order to solve environmental problems such as global warming and resource depletion in the construction industry, interest in new renewable energy (NRE systems has increased. The ground source heat pump (GSHP system is the most efficient system among NRE systems. However, since the initial investment cost of the GSHP is quite expensive, a feasibility study needs to be conducted from the life-cycle perspective. Meanwhile, the efficiency of GSHP depends most significantly on the entering water temperature (EWT of the ground heat exchanger (GHE. Therefore, this study aims to assess the environmental and economic effects of the use of GHE for selecting the optimal GHE. This study was conducted in three steps: (i establishing the basic information and selecting key factors affecting GHE performances; (ii making possible alternatives of the GHE installation by considering EWT; and (iii using life-cycle assessment and life-cycle cost, as well as comprehensive evaluation of the environmental and economic effects on the GHE. These techniques allow for easy and accurate determination of the optimal design of the GHE from the environmental and economic effects in the early design phase. In future research, a multi-objective decision support model for the GSHP will be developed.

  6. Research on Reliability and Cost Integrated Optimization Algorithm of Construction Project Logistics System

    Directory of Open Access Journals (Sweden)

    Xiaoping Bai

    2013-01-01

    Full Text Available The structure of the construction project logistics system is decomposed in detail; some uncertain factors affecting system reliability are analyzed. This paper applies the probability-influence coordinate graph to screen out the logistics subsystem that has great influence on system reliability under the conditions of occurring failure, and establishes an allocation model of the reliability index in construction project logistics system based on the restriction of cost, makes use of the presented model and algorithm to calculate the cost-based reliability, contrasts it with the index reliability assigned by the scoring method to the optimal distribution value of reliability index and the optimal cost. The presented detailed methods and steps can offer the meaningful reference for reliability optimization management of the logistics system in the construction project.

  7. Investment-Cost Optimization of Plastic Recycling System under Reliability Constraints

    Directory of Open Access Journals (Sweden)

    Abdelkader ZEBLAH

    2008-06-01

    Full Text Available This paper describes and uses an ant colony meta-heuristic optimization method to solve the redundancy optimization problem in plastic recycling industry. This problem is known as total investment-cost minimization of series-parallel plastic recycling system. Redundant components are included to achieve a desired level of availability. System availability is represented by a multi-state availability function. The plastic machines are characterized by their capacity, availability and cost. These machines are chosen among a list of products available on the market. The proposed meta-heuristic seeks to find the best minimal cost plastic recycling system configuration with desired availability. To estimate the series-parallel plastic machines availability, a fast method based on universal moment generating function (UMGF is suggested. The ant colony approach is used as an optimization technique. An example of plastic recycling system is presented.

  8. Influence of Cooling to Heating Load Ratio on Optimal Supply Water and Air Temperatures in an Air Conditioning System

    Science.gov (United States)

    Karino, Naoki; Shiba, Takashi; Yokoyama, Ryohei; Ito, Koichi

    In planning an air conditioning system, supply water and air temperatures are important factors from the viewpoint of energy saving and cost reduction. For example, lower temperature supply water and air for space cooling reduce the coefficient of performance of a refrigeration machine, and increase the thickness of heat insulation material. However, they enable larger temperature differences, and reduce equipment sizes and power demand. It is also an important subject to evaluate the effect of the supply water and air temperatures on energy saving and cost reduction on the annual basis by considering not only cooling but also heating loads. The purposes of this paper are to propose an optimal planning method for an air conditioning system with large temperature difference, and to analyze the effect of supply water and air temperatures on the long-term economics through a numerical study for an office building. As a result, it is shown that the proposed method effectively determines supply water and air temperatures, and the influence of the cooling to heating load ratio on the long-term economics is clarified.

  9. Optimal wall spacing for heat transport in thermal convection

    Energy Technology Data Exchange (ETDEWEB)

    Shishkina, Olga [Max Planck Institute for Dynamics and Self-Organization, Goettingen (Germany)

    2016-11-01

    The simulation of RB flow for Ra up to 1 x 10{sup 10} is computationally expensive in terms of computing power and hard disk storage. Thus, we gratefully acknowledge the computational resources supported by Leibniz-Rechenzentrum Munich. Compared to Γ=1 situation, a new physical picture of heat transport is identified here at Γ{sub opt} for any explored Ra. Therefore, a detailed comparison between Γ=1 and Γ=Γ{sub opt} is valuable for our further research, for example, their vertical temperature and velocity profiles. Additionally, we plan to compare the fluid with different Pr under geometrical confinement, which are computationally expensive for the situations of Pr<<1 and Pr>>1.

  10. Exotic properties and optimal control of quantum heat engine

    Science.gov (United States)

    Ou, Congjie; Abe, Sumiyoshi

    2016-02-01

    A quantum heat engine of a specific type is studied. This engine contains a single particle confined in the infinite square well potential with variable width and consists of three processes: the isoenergetic process (which has no classical analogs) as well as the isothermal and adiabatic processes. It is found that the engine possesses exotic properties in its performance. The efficiency takes the maximum value when the expansion ratio of the engine is appropriately set, and, in addition, the lower the temperature is, the higher the maximum efficiency becomes, highlighting aspects of the influence of quantum effects on thermodynamics. A comment is also made on the relevance of this engine to that of Carnot.

  11. Optimal Design of a Thermoelectric Cooling/Heating System for Car Seat Climate Control (CSCC)

    Science.gov (United States)

    Elarusi, Abdulmunaem; Attar, Alaa; Lee, Hosung

    2016-12-01

    In the present work, the optimum design of thermoelectric car seat climate control (CSCC) is studied analytically in an attempt to achieve high system efficiency. Optimal design of a thermoelectric device (element length, cross-section area and number of thermocouples) is carried out using our newly developed optimization method based on the ideal thermoelectric equations and dimensional analysis to improve the performance of the thermoelectric device in terms of the heating/cooling power and the coefficient of performance (COP). Then, a new innovative system design is introduced which also includes the optimum input current for the initial (transient) startup warming and cooling before the car heating ventilation and air conditioner (HVAC) is active in the cabin. The air-to-air heat exchanger's configuration was taken into account to investigate the optimal design of the CSCC.

  12. Optimal Design of a Thermoelectric Cooling/Heating System for Car Seat Climate Control (CSCC)

    Science.gov (United States)

    Elarusi, Abdulmunaem; Attar, Alaa; Lee, Hosung

    2017-04-01

    In the present work, the optimum design of thermoelectric car seat climate control (CSCC) is studied analytically in an attempt to achieve high system efficiency. Optimal design of a thermoelectric device (element length, cross-section area and number of thermocouples) is carried out using our newly developed optimization method based on the ideal thermoelectric equations and dimensional analysis to improve the performance of the thermoelectric device in terms of the heating/cooling power and the coefficient of performance (COP). Then, a new innovative system design is introduced which also includes the optimum input current for the initial (transient) startup warming and cooling before the car heating ventilation and air conditioner (HVAC) is active in the cabin. The air-to-air heat exchanger's configuration was taken into account to investigate the optimal design of the CSCC.

  13. Optimization of automotive Rankine cycle waste heat recovery under various engine operating condition

    Science.gov (United States)

    Punov, Plamen; Milkov, Nikolay; Danel, Quentin; Perilhon, Christelle; Podevin, Pierre; Evtimov, Teodossi

    2017-02-01

    An optimization study of the Rankine cycle as a function of diesel engine operating mode is presented. The Rankine cycle here, is studied as a waste heat recovery system which uses the engine exhaust gases as heat source. The engine exhaust gases parameters (temperature, mass flow and composition) were defined by means of numerical simulation in advanced simulation software AVL Boost. Previously, the engine simulation model was validated and the Vibe function parameters were defined as a function of engine load. The Rankine cycle output power and efficiency was numerically estimated by means of a simulation code in Python(x,y). This code includes discretized heat exchanger model and simplified model of the pump and the expander based on their isentropic efficiency. The Rankine cycle simulation revealed the optimum value of working fluid mass flow and evaporation pressure according to the heat source. Thus, the optimal Rankine cycle performance was obtained over the engine operating map.

  14. Techno-economic analysis of using corn stover to supply heat and power to a corn ethanol plant - Part 2: Cost of heat and power generation systems

    Energy Technology Data Exchange (ETDEWEB)

    Mani, Sudhagar [University of Georgia; Sokhansanj, Shahabaddine [ORNL; Togore, Sam [U.S. Department of Energy; Turhollow Jr, Anthony F [ORNL

    2010-03-01

    This paper presents a techno-economic analysis of corn stover fired process heating (PH) and the combined heat and power (CHP) generation systems for a typical corn ethanol plant (ethanol production capacity of 170 dam3). Discounted cash flow method was used to estimate both the capital and operating costs of each system and compared with the existing natural gas fired heating system. Environmental impact assessment of using corn stover, coal and natural gas in the heat and/or power generation systems was also evaluated. Coal fired process heating (PH) system had the lowest annual operating cost due to the low fuel cost, but had the highest environmental and human toxicity impacts. The proposed combined heat and power (CHP) generation system required about 137 Gg of corn stover to generate 9.5 MW of electricity and 52.3 MW of process heat with an overall CHP efficiency of 83.3%. Stover fired CHP system would generate an annual savings of 3.6 M$ with an payback period of 6 y. Economics of the coal fired CHP system was very attractive compared to the stover fired CHP system due to lower fuel cost. But the greenhouse gas emissions per Mg of fuel for the coal fired CHP system was 32 times higher than that of stover fired CHP system. Corn stover fired heat and power generation system for a corn ethanol plant can improve the net energy balance and add environmental benefits to the corn to ethanol biorefinery.

  15. Techno-economic analysis of using corn stover to supply heat and power to a corn ethanol plant - Part 2: Cost of heat and power generation systems

    Energy Technology Data Exchange (ETDEWEB)

    Mani, S. [Biological and Agricultural Engineering, Driftmier Engineering Center, University of Georgia, Athens, GA 30602 (United States); Sokhansanj, S.; Turhollow, A.F. [Environmental Sciences Division, Oak Ridge National Laboratory, P. O. Box 2008, Oak Ridge, TN 37831 (United States); Tagore, S. [Office of Biomass Program, U.S. Department of Energy, Washington, DC 20585 (United States)

    2010-03-15

    This paper presents a techno-economic analysis of corn stover fired process heating (PH) and the combined heat and power (CHP) generation systems for a typical corn ethanol plant (ethanol production capacity of 170 dam{sup 3}). Discounted cash flow method was used to estimate both the capital and operating costs of each system and compared with the existing natural gas fired heating system. Environmental impact assessment of using corn stover, coal and natural gas in the heat and/or power generation systems was also evaluated. Coal fired process heating (PH) system had the lowest annual operating cost due to the low fuel cost, but had the highest environmental and human toxicity impacts. The proposed combined heat and power (CHP) generation system required about 137 Gg of corn stover to generate 9.5 MW of electricity and 52.3 MW of process heat with an overall CHP efficiency of 83.3%. Stover fired CHP system would generate an annual savings of 3.6 M$ with an payback period of 6 y. Economics of the coal fired CHP system was very attractive compared to the stover fired CHP system due to lower fuel cost. But the greenhouse gas emissions per Mg of fuel for the coal fired CHP system was 32 times higher than that of stover fired CHP system. Corn stover fired heat and power generation system for a corn ethanol plant can improve the net energy balance and add environmental benefits to the corn to ethanol biorefinery. (author)

  16. Energy analysis of the engineering-economic optimization of convective heat-transfer surfaces

    Science.gov (United States)

    Stoyanov, N. M.

    1991-07-01

    The influence of the specific costs of the heat transfer surface, 1 kW of installed power of the blower and motor, 1 kW·h of electrical energy consumption by it, operating time of the surface, and other factors on the optimum specific power expenditure to force heat-transfer fluids through the ducts of heattransfer surfaces is investigated. The minimum engineering-economically justified operating time of the surface is determined.

  17. Cost Optimal Reliability Based Inspection and Replacement Planning of Piping Subjected to CO2 Corrosion

    DEFF Research Database (Denmark)

    Hellevik, S. G.; Langen, I.; Sørensen, John Dalsgaard

    1999-01-01

    A methodology for cost optimal reliability based inspection and replacement planning of piping subjected to CO2 corrosion is described. Both initial (design phase) and in-service planning are dealt with. The methodology is based on the application of methods for structural reliability analysis...... within the framework of Bayesian decision theory. The planning problem is formulated as an optimization problem where the expected lifetime costs are minimized with a constraint on the minimum acceptable reliability level. The optimization parameters are the number of inspections in the expected lifetime......, the inspection times and methods. In the design phase the nominal design wall thickness is also treated as an optimization parameter. The most important benefits gained through the application of the methodology are consistent evaluation of the consequences of different inspection and replacement plans...

  18. Optimal Power Flow With UPFC Using Fuzzy- PSO With NonSmooth Fuel Cost Function

    Directory of Open Access Journals (Sweden)

    A.Immanuel

    2015-05-01

    Full Text Available This paper presents an efficient and reliable evolutionary based approach to solve the Optimal Power Flow problem in electrical power network. The Particle Swarm Optimization method is used to solve optimal power Flow problem in power system by incorporating a powerful and most versatile Flexible Alternating Current Transmission Systems device such as Unified power Flow Controller. It is a new device in FACTS family and has great flexibility that can control Active power, Reactive power and voltage magnitudes simultaneously. In this paper optimal location is find out using Fuzzy approach and control settings of UPFC are determined by PSO. The proposed approach is examined on IEEE-30 bus system with different objective function that reflects fuel cost minimization and fuel cost with valve point effects. The test results show the effectiveness of robustness of the proposed approachcompared with the existing results in the literature.

  19. Solar energy for process heat: Design/cost studies of four industrial retrofit applications

    Science.gov (United States)

    French, R. L.; Bartera, R. E.

    1978-01-01

    Five specific California plants with potentially attractive solar applications were identified in a process heat survey. These five plants were visited, process requirements evaluated, and conceptual solar system designs were generated. Four DOE (ERDA) sponsored solar energy system demonstration projects were also reviewed and compared to the design/cost cases included in this report. In four of the five cases investigated, retrofit installations providing significant amounts of thermal energy were found to be feasible. The fifth was rejected because of the condition of the building involved, but the process (soap making) appears to be an attractive potential solar application. Costs, however, tend to be high. Several potential areas for cost reduction were identified including larger collector modules and higher duty cycles.

  20. Sequential Optimization of Paths in Directed Graphs Relative to Different Cost Functions

    KAUST Repository

    Mahayni, Malek A.

    2011-07-01

    Finding optimal paths in directed graphs is a wide area of research that has received much of attention in theoretical computer science due to its importance in many applications (e.g., computer networks and road maps). Many algorithms have been developed to solve the optimal paths problem with different kinds of graphs. An algorithm that solves the problem of paths’ optimization in directed graphs relative to different cost functions is described in [1]. It follows an approach extended from the dynamic programming approach as it solves the problem sequentially and works on directed graphs with positive weights and no loop edges. The aim of this thesis is to implement and evaluate that algorithm to find the optimal paths in directed graphs relative to two different cost functions ( , ). A possible interpretation of a directed graph is a network of roads so the weights for the function represent the length of roads, whereas the weights for the function represent a constraint of the width or weight of a vehicle. The optimization aim for those two functions is to minimize the cost relative to the function and maximize the constraint value associated with the function. This thesis also includes finding and proving the relation between the two different cost functions ( , ). When given a value of one function, we can find the best possible value for the other function. This relation is proven theoretically and also implemented and experimented using Matlab®[2].

  1. Research on Optimal Delivery Days and Customer Satisfaction Based on Quality Costs

    Institute of Scientific and Technical Information of China (English)

    薛伟; 周宏彤; 陈亚绒

    2004-01-01

    Customer satisfaction is an important index to evaluate the competitiveness and efficiency of an enterprise. Every enterprise is confront with the subject of supplying with the customer satisfactory products at the lowest costs and the highest manufacturing speed. Regarding the delivery days of a coach company as a design variable, this paper builds up an optimization model of customer satisfaction, and suggests an effective method to reduce costs and increase customer satisfaction based on analysis and research.

  2. Optimal insulation of pipes and tanks for solar heating systems. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    Jones, G F; Lior, N

    1979-02-01

    A compact and time effective insulation design procedure for solar heating system piping and water-filled thermal storage tanks was developed. Recognizing the particular sensitivity of solar systems to cost, the economic aspect of the problem is treated by a comprehensive present-value life-cycle cost analysis. In the development of the method, a numerical sensitivity analysis was performed to determine the relative effects of all relevant independent variables (within their pertinent ranges) on piping and tank heat transfer coefficient values.

  3. Energy Savings and Breakeven Cost for Residential Heat Pump Water Heaters in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Maguire, J.; Burch, J.; Merrigan, T.; Ong, S.

    2013-07-01

    Heat pump water heaters (HPWHs) have recently reemerged in the U.S. residential water heating market and have the potential to provide homeowners with significant energy savings. However, there are questions as to the actual performance and energy savings potential of these units, in particular in regards to the heat pump's performance in unconditioned space and the impact of the heat pump on space heating and cooling loads when it is located in conditioned space. To help answer these questions, simulations were performed of a HPWH in both conditioned and unconditioned space at over 900 locations across the continental United States and Hawaii. Simulations included a Building America benchmark home so that any interaction between the HPWH and the home's HVAC equipment could be captured. Comparisons were performed to typical gas and electric water heaters to determine the energy savings potential and cost effectiveness of a HPWH relative to these technologies. HPWHs were found to have a significant source energy savings potential when replacing typical electric water heaters, but only saved source energy relative to gas water heater in the most favorable installation locations in the southern US. When replacing an electric water heater, the HPWH is likely to break even in California, the southern US, and parts of the northeast in most situations. However, the HPWH will only break even when replacing a gas water heater in a few southern states.

  4. Energy Savings and Breakeven Costs for Residential Heat Pump Water Heaters in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Maguire, Jeff [National Renewable Energy Lab. (NREL), Golden, CO (United States); Burch, Jay [National Renewable Energy Lab. (NREL), Golden, CO (United States); Merrigan, Tim [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ong, Sean [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-07-01

    Heat pump water heaters (HPWHs) have recently re-emerged in the U.S. residential water heating market and have the potential to provide homeowners with significant energy savings. However, there are questions as to the actual performance and energy savings potential of these units, in particular in regards to the heat pump's performance in unconditioned space and the impact of the heat pump on space heating and cooling loads when it is located in conditioned space. To help answer these questions, NREL performed simulations of a HPWH in both conditioned and unconditioned space at over 900 locations across the continental United States and Hawaii. Simulations included a Building America benchmark home so that any interaction between the HPWH and the home's HVAC equipment could be captured. Comparisons were performed to typical gas and electric water heaters to determine the energy savings potential and cost effectiveness of a HPWH relative to these technologies. HPWHs were found to have a significant source energy savings potential when replacing typical electric water heaters, but only saved source energy relative to gas water heater in the most favorable installation locations in the southern United States. When replacing an electric water heater, the HPWH is likely to break even in California, the southern United States, and parts of the northeast in most situations. However, the HPWH will only break even when replacing a gas water heater in a few southern states.

  5. Sequential Optimization of Global Sequence Alignments Relative to Different Cost Functions

    KAUST Repository

    Odat, Enas M.

    2011-05-01

    The purpose of this dissertation is to present a methodology to model global sequence alignment problem as directed acyclic graph which helps to extract all possible optimal alignments. Moreover, a mechanism to sequentially optimize sequence alignment problem relative to different cost functions is suggested. Sequence alignment is mostly important in computational biology. It is used to find evolutionary relationships between biological sequences. There are many algo- rithms that have been developed to solve this problem. The most famous algorithms are Needleman-Wunsch and Smith-Waterman that are based on dynamic program- ming. In dynamic programming, problem is divided into a set of overlapping sub- problems and then the solution of each subproblem is found. Finally, the solutions to these subproblems are combined into a final solution. In this thesis it has been proved that for two sequences of length m and n over a fixed alphabet, the suggested optimization procedure requires O(mn) arithmetic operations per cost function on a single processor machine. The algorithm has been simulated using C#.Net programming language and a number of experiments have been done to verify the proved statements. The results of these experiments show that the number of optimal alignments is reduced after each step of optimization. Furthermore, it has been verified that as the sequence length increased linearly then the number of optimal alignments increased exponentially which also depends on the cost function that is used. Finally, the number of executed operations increases polynomially as the sequence length increase linearly.

  6. Cost-optimal power system extension under flow-based market coupling

    Energy Technology Data Exchange (ETDEWEB)

    Hagspiel, Simeon; Jaegemann, Cosima; Lindenberger, Dietmar [Koeln Univ. (Germany). Energiewirtschaftliches Inst.; Brown, Tom; Cherevatskiy, Stanislav; Troester, Eckehard [Energynautics GmbH, Langen (Germany)

    2013-05-15

    Electricity market models, implemented as dynamic programming problems, have been applied widely to identify possible pathways towards a cost-optimal and low carbon electricity system. However, the joint optimization of generation and transmission remains challenging, mainly due to the fact that different characteristics and rules apply to commercial and physical exchanges of electricity in meshed networks. This paper presents a methodology that allows to optimize power generation and transmission infrastructures jointly through an iterative approach based on power transfer distribution factors (PTDFs). As PTDFs are linear representations of the physical load flow equations, they can be implemented in a linear programming environment suitable for large scale problems. The algorithm iteratively updates PTDFs when grid infrastructures are modified due to cost-optimal extension and thus yields an optimal solution with a consistent representation of physical load flows. The method is first demonstrated on a simplified three-node model where it is found to be robust and convergent. It is then applied to the European power system in order to find its cost-optimal development under the prescription of strongly decreasing CO{sub 2} emissions until 2050.

  7. Cost versus life cycle assessment-based environmental impact optimization of drinking water production plants.

    Science.gov (United States)

    Capitanescu, F; Rege, S; Marvuglia, A; Benetto, E; Ahmadi, A; Gutiérrez, T Navarrete; Tiruta-Barna, L

    2016-07-15

    Empowering decision makers with cost-effective solutions for reducing industrial processes environmental burden, at both design and operation stages, is nowadays a major worldwide concern. The paper addresses this issue for the sector of drinking water production plants (DWPPs), seeking for optimal solutions trading-off operation cost and life cycle assessment (LCA)-based environmental impact while satisfying outlet water quality criteria. This leads to a challenging bi-objective constrained optimization problem, which relies on a computationally expensive intricate process-modelling simulator of the DWPP and has to be solved with limited computational budget. Since mathematical programming methods are unusable in this case, the paper examines the performances in tackling these challenges of six off-the-shelf state-of-the-art global meta-heuristic optimization algorithms, suitable for such simulation-based optimization, namely Strength Pareto Evolutionary Algorithm (SPEA2), Non-dominated Sorting Genetic Algorithm (NSGA-II), Indicator-based Evolutionary Algorithm (IBEA), Multi-Objective Evolutionary Algorithm based on Decomposition (MOEA/D), Differential Evolution (DE), and Particle Swarm Optimization (PSO). The results of optimization reveal that good reduction in both operating cost and environmental impact of the DWPP can be obtained. Furthermore, NSGA-II outperforms the other competing algorithms while MOEA/D and DE perform unexpectedly poorly.

  8. Optimization of microchannel heat sink using genetic algorithm and Taguchi method

    Science.gov (United States)

    Singh, Bhanu Pratap; Garg, Harry; Lall, Arun K.

    2016-04-01

    Active cooling using microchannel is a challenging area. The optimization and miniaturization of the devices is increasing the heat loads and affecting the operating performance of the system. The microchannel based cooling systems are widely used and overcomes most of the limitations of the existing solutions. Microchannels help in reducing dimensions and therefore finding many important applications in the microfluidics domain. The microchannel performance is related to the geometry, material and flow conditions. Optimized selection of controllable parameters is a key issue while designing the microchannel based cooling system. The proposed work presents a simulation based study according to Taguchi design of experiment with Reynolds number, aspect ratio and plenum length as input parameters to determine SN ratio. The objective of this study is to maximize the heat transfer. Mathematical models based on these parameters were developed which helps in global optimization using Genetic Algorithm. Genetic algorithm further employed to optimize the input parameters and generates global solution points for the proposed work. It was concluded that the optimized value for heat transfer coefficient and Nusselt number was 2620.888 W/m2K and 3.4708 as compare to values obtained through SN ratio based parametric study i.e. 2601.3687 W/m2K and 3.447 respectively. Hence an error of 0.744% and 0.68% was detected in heat transfer coefficient and Nusselt number respectively.

  9. Optimization of interference filters with genetic algorithms applied to silver-based heat mirrors.

    Science.gov (United States)

    Eisenhammer, T; Lazarov, M; Leutbecher, M; Schöffel, U; Sizmann, R

    1993-11-01

    In the optimization of multilayer stacks for various optical filtering purposes not only the thicknesses of the thin films are to be optimized, but also the sequence of materials. Materials with very different optical properties, such as metals and dielectrics, may be combined. A genetic algorithm is introduced to search for the optimal sequence of materials along with their optical thicknesses. This procedure is applied to a heat mirror in combination with a blackbody absorber for thermal solar energy applications at elevated temperatures (250 °C). The heat mirror is based on silver films with antireflective dielectric layers. Seven dielectrics have been considered. For a five-layer stack the sequence (TiO(2)/Ag/TiO(2)/Ag/Y(2)O(3)) is found to be optimal.

  10. Multi-objective optimization of a plate and frame heat exchanger via genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Najafi, Hamidreza; Najafi, Behzad [K. N. Toosi University of Technology, Department of Mechanical Engineering, Tehran (Iran)

    2010-06-15

    In the present paper, a plate and frame heat exchanger is considered. Multi-objective optimization using genetic algorithm is developed in order to obtain a set of geometric design parameters, which lead to minimum pressure drop and the maximum overall heat transfer coefficient. Vividly, considered objective functions are conflicting and no single solution can satisfy both objectives simultaneously. Multi-objective optimization procedure yields a set of optimal solutions, called Pareto front, each of which is a trade-off between objectives and can be selected by the user, regarding the application and the project's limits. The presented work takes care of numerous geometric parameters in the presence of logical constraints. A sensitivity analysis is also carried out to study the effects of different geometric parameters on the considered objective functions. Modeling the system and implementing the multi-objective optimization via genetic algorithm has been performed by MATLAB. (orig.)

  11. Optimized transparent and heat reflecting oxide and nitride films

    Energy Technology Data Exchange (ETDEWEB)

    Howson, R.P.; Ridge, M.I.; Suzuki, K.

    1984-11-01

    Films of indium oxide and indium oxide doped with tin have been produced by reactive planar magnetron sputtering of the pure metal and the alloy and from two metal sources simultaneously. In each case the oxygen partial pressure was controlled to give the higher sheet resistance in the oxide film which was deposited onto a plastic sheet transferred over a drum at ambient temperature. Films prepared under these conditions with the best properties for heat reflecting and visible transparent filters were found to be the oxide of the pure metal. A radio frequency discharge used in conjunction with the magnetron allowed the operating pressure to be considerably reduced, which allowed the preparation of titanium nitride films from a titanium metal target and the construction of simple metal and dielectric-metal-dielectric filters, which match theoretical predictions. A sandwich filter could be made from one titanium target by varying the active gas between oxygen and nitrogen to give a structure of: TiO/sub 2/-TiN-TiO/sub 2/. (A.V.)

  12. Optimal temperature range for determining magnetocaloric magnitudes from heat capacity

    Science.gov (United States)

    Moreno-Ramírez, L. M.; Blázquez, J. S.; Law, J. Y.; Franco, V.; Conde, A.

    2016-12-01

    The determination of the magnetocaloric magnitudes (specific magnetic entropy change, Δs M, and adiabatic temperature change, ΔT ad) from heat capacity (c H) measurements requires measurements performed at very low temperatures (~0 K) or data extrapolation when the low temperature range is unavailable. In this work we analyze the influence on the calculated Δs M and ΔT ad of the usually employed linear extrapolation of c H from the initial measured temperature down to 0 K. Numerical simulations have been performed using the Brillouin equation of state, the Debye model and the Fermi electron statistics to reproduce the magnetic, lattice and electronic subsystems, respectively. It is demonstrated that it is not necessary to reach experimentally temperatures very close to 0 K due to the existence of certain starting temperatures of the experiments, the same for Δs M and ΔT ad, that minimize the error of the results. A procedure is proposed to obtain the experimental magnitudes of Δs M and ΔT ad with a minimum error from c H data limited in temperature. It has been successfully applied to a GdZn alloy and results are compared to those derived from magnetization measurements.

  13. Optimized Transparent And Heat Reflecting Oxide And Nitride Films

    Science.gov (United States)

    Howson, Ronald P.; Ridge, Martin I.; Suzuki, Koichi

    1983-12-01

    Films of indium oxide and indium oxide doped with tin have been produced by reactive planar magnetron sputtering of the pure metal and the alloy and from two metal sources simultaneously. In each case the oxygen partial pressure was controlled to give the highest sheet resistance in the oxide film which was deposited onto a plastic sheet transferred over a drum at ambient temperature. Films prepared under these conditions with the best properties for heat reflecting and visible transparent filters were found to be the oxide of the pure metal. A radio frequency discharge used in conjunction with the magnetron allowed the operating pressure to be considerably reduced, which allowed the preparation of titanium nitride films from a titanium metal target and the construction of simple metal and dielectric-metal-dielectric filters, which match theoretical predictions. A sandwich filter could be made from one titanium target by varying the active gas between oxygen and nitrogen to give a structure of: TiO2 - TiN - Ti02.

  14. Optimal Homotopy Asymptotic Solution for Exothermic Reactions Model with Constant Heat Source in a Porous Medium

    Directory of Open Access Journals (Sweden)

    Fazle Mabood

    2015-01-01

    Full Text Available The heat flow patterns profiles are required for heat transfer simulation in each type of the thermal insulation. The exothermic reaction models in porous medium can prescribe the problems in the form of nonlinear ordinary differential equations. In this research, the driving force model due to the temperature gradients is considered. A governing equation of the model is restricted into an energy balance equation that provides the temperature profile in conduction state with constant heat source on the steady state. The proposed optimal homotopy asymptotic method (OHAM is used to compute the solutions of the exothermic reactions equation.

  15. Implementation of transmission functions for an optimized three-terminal quantum dot heat engine

    Science.gov (United States)

    Schiegg, Christian H.; Dzierzawa, Michael; Eckern, Ulrich

    2017-03-01

    We consider two modifications of a recently proposed three-terminal quantum dot heat engine. First, we investigate the necessity of the thermalization assumption, namely that electrons are always thermalized by inelastic processes when traveling across the cavity where the heat is supplied. Second, we analyze various arrangements of tunneling-coupled quantum dots in order to implement a transmission function that is superior to the Lorentzian transmission function of a single quantum dot. We show that the maximum power of the heat engine can be improved by about a factor of two, even for a small number of dots, by choosing an optimal structure.

  16. Study, optimization, and design of a laser heat engine. [for satellite applications

    Science.gov (United States)

    Taussig, R. T.; Cassady, P. E.; Zumdieck, J. F.

    1978-01-01

    Laser heat engine concepts, proposed for satellite applications, are analyzed to determine which engine concept best meets the requirements of high efficiency (50 percent or better), continuous operation in space using near-term technology. The analysis of laser heat engines includes the thermodynamic cycles, engine design, laser power sources, collector/concentrator optics, receiving windows, absorbers, working fluids, electricity generation, and heat rejection. Specific engine concepts, optimized according to thermal efficiency, are rated by their technological availability and scaling to higher powers. A near-term experimental demonstration of the laser heat engine concept appears feasible utilizing an Otto cycle powered by CO2 laser radiation coupled into the engine through a diamond window. Higher cycle temperatures, higher efficiencies, and scalability to larger sizes appear to be achievable from a laser heat engine design based on the Brayton cycle and powered by a CO laser.

  17. A multiple ship routing and speed optimization problem under time, cost and environmental objectives

    DEFF Research Database (Denmark)

    Wen, M.; Pacino, Dario; Kontovas, C.A.

    2017-01-01

    The purpose of this paper is to investigate a multiple ship routing and speed optimization problem under time, cost and environmental objectives. A branch and price algorithm as well as a constraint programming model are developed that consider (a) fuel consumption as a function of payload, (b......) fuel price as an explicit input, (c) freight rate as an input, and (d) in-transit cargo inventory costs. The alternative objective functions are minimum total trip duration, minimum total cost and minimum emissions. Computational experience with the algorithm is reported on a variety of scenarios....

  18. Assessment of various failure theories for weight and cost optimized laminated composites using genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, T. [Indian Institute of Technology Kanpur. Dept. of Aerospace Engineering, UP (India); Gupta, R. [Infotech Enterprises Ltd., Hyderabad (India)

    2012-07-01

    In this work, minimum weight-cost design for laminated composites is presented. A genetic algorithm has been developed for the optimization process. Maximum-Stress, Tsai-Wu and Tsai-Hill failure criteria have been used along with buckling analysis parameter for the margin of safety calculations. The design variables include three materials; namely Carbon-Epoxy, Glass-Epoxy, Kevlar-Epoxy; number of plies; ply orientation angles, varying from -75 deg. to 90 deg. in the intervals of 15 deg. and ply thicknesses which depend on the material in use. The total cost is a sum of material cost and layup cost. Layup cost is a function of the ply angle. Validation studies for solution convergence and weight-cost inverse proportionality are carried out. One set of results for shear loading are also validated from literature for a particular case. A Pareto-Optimal solution set is demonstrated for biaxial loading conditions. It is then extended to applied moments. It is found that global optimum for a given loading condition is a function of the failure criteria for shear loading, with Maximum Stress criteria giving the lightest-cheapest and Tsai-Wu criteria giving the heaviest-costliest optimized laminates. Optimized weight results are plotted from the three criteria to do a comparative study. This work gives a global optimized laminated composite and also a set of other local optimum laminates for a given set of loading conditions. The current algorithm also provides with adequate data to supplement the use of different failure criteria for varying loadings. This work can find use in the industry and/or academia considering the increased use of laminated composites in modern wind blades. (Author)

  19. Experimental investigation on optimal temperature lift of an inverter heat pump system

    Directory of Open Access Journals (Sweden)

    Wang Fang

    2013-01-01

    Full Text Available The temperature lift directly influences the efficiency of the heat pump, meanwhile, the coefficient of performance and the heat sink temperature lift of heat pump systems are mutually exclusive parameters, i.e., the higher temperature lift leads to the lower coefficient of performance while the lower temperature lift leads to the higher coefficient of performance. To deal with the dilemma, a primary theoretical analysis is performed, and a case study of an inverter water source heat pump is carried out, which is operated under the conditions of compressor frequency of 15-85 Hz and heat sink flow rate of 120/160/180/200 kg/h, respectively. The relationships among the temperature lift, coefficient of performance and compressor power consumption are analyzed, The results show that the optimal temperature lift mainly depends on the inlet temperature of heat sink, and has little to do with the compressor frequency and water flow rate, which are of significance for the optimal operation of heat pump systems.

  20. Design Optimization of Heat Wheels for Energy Recovery in HVAC Systems

    Directory of Open Access Journals (Sweden)

    Stefano De Antonellis

    2014-11-01

    Full Text Available Air to air heat exchangers play a crucial role in mechanical ventilation equipment, due to the potential primary energy savings both in case of refurbishment of existing buildings or in case of new ones. In particular, interest in heat wheels is increasing due to their low pressure drop and high effectiveness. In this paper a detailed optimization of design parameters of heat wheels is performed in order to maximize sensible effectiveness and to minimize pressure drop. The analysis is carried out through a one dimensional lumped parameters heat wheel model, which solves heat and mass transfer equations, and through appropriate correlations to estimate pressure drop. Simulation results have been compared with experimental data of a heat wheel tested in specific facilities, and good agreement is attained. The device optimization is performed through the variation of main design parameters, such as heat wheel length, channel base, height and thickness and for different operating conditions, namely the air face velocity and the revolution speed. It is shown that the best configurations are achieved with small channel thickness and, depending on the required sensible effectiveness, with appropriate values of wheel length and channel base and height.

  1. Optimization of a commercial, medium size, reversible heat pump for use with propane

    Energy Technology Data Exchange (ETDEWEB)

    Corberan, J.M. [Dept. of Applied Thermodynamics, Univ. Politecnica de Valencia (Spain); Urchueguia, J.F. [Dept. of Applied Physics, Univ. Politecnica de Valencia (Spain); Conde, M. [Manuel Conde Eng., Zuerich (Switzerland); Setaro, T. [Ente per le Nuove Tecnologie, l' Energia e l' Ambiente (ENEA), Energy Dept., S.M. di Galeria (Italy); Sartori, L.; Zorzin, A. [Alfa Laval-Artec Spa, Alonte (Italy); Granryd, E.; Palm, B. [Kungl Tekniska Hokskolan, Stockholm (Sweden); Saez, J.; Ramos, A. [Cia. Industrial de Aplicaciones Tecnicas S.A., Cordoba (Spain); Blas, J. de [Asociacion Espanola para la Diagnosis y la Investigacion en Energia (AEDIE), Madrid (Spain)

    1999-07-01

    In this paper we give a summarized description of the HEAHP/J3 project, currently running under the support of the European Commission. In the frame of this project, a medium size reversible air to water heat pump for use with propane (R290) and appropriate for south European countries - in which refrigeration is a strong demand - is currently being developed by the partners. The starting point is a 20 kW, R22, commercial heat pump from CIATESA, a major Spanish heat pump manufacturer, which will be adapted and optimized for the use of propane as refrigerant. Computer simulations are under development aiming to identify the improvements and/or modifications needed in the components to ensure safe use and high efficiency, in terms of COP, of the heat pump. The scope of these models is to assist the optimization and design of the different elements of the heat pump. To aid the adjustment of these models while generating a large database covering the behavior of propane as a refrigerant, individualized characterization experiments of all pump components will be performed. Both aspects, modeling and measurements, are issued to converge in the reduction of size of all components resulting from the use of efficient extended surfaces in the heat exchangers and (for a given refrigeration or heat capacity) in the improvement of overall efficiency through the appropriate selection or adaptation, as far as possible, of the compressor. (orig.)

  2. Two-scale cost efficiency optimization of 5G wireless backhaul networks

    OpenAIRE

    Ge, Xiaohu; Tu, Song; Mao, Guoqiang; Lau, Vincent K. N.; Pan, Linghui

    2016-01-01

    To cater for the demands of future fifth generation (5G) ultra-dense small cell networks, the wireless backhaul network is an attractive solution for the urban deployment of 5G wireless networks. Optimization of 5G wireless backhaul networks is a key issue. In this paper we propose a two-scale optimization solution to maximize the cost efficiency of 5G wireless backhaul networks. Specifically, the number and positions of gateways are optimized in the long time scale of 5G wireless backhaul ne...

  3. Two-scale cost efficiency optimization of 5G wireless backhaul networks

    OpenAIRE

    Ge, Xiaohu; Tu, Song; Mao, Guoqiang; Lau, Vincent K. N.; Pan, Linghui

    2016-01-01

    To cater for the demands of future fifth generation (5G) ultra-dense small cell networks, the wireless backhaul network is an attractive solution for the urban deployment of 5G wireless networks. Optimization of 5G wireless backhaul networks is a key issue. In this paper we propose a two-scale optimization solution to maximize the cost efficiency of 5G wireless backhaul networks. Specifically, the number and positions of gateways are optimized in the long time scale of 5G wireless backhaul ne...

  4. Optimal control of a large dam, taking into account the water costs [New Edition

    CERN Document Server

    Abramov, Vyacheslav M

    2009-01-01

    This paper studies large dam models where the difference between lower and upper levels $L$ is assumed to be large. Passage across the levels leads to damage, and the damage costs of crossing the lower or upper level are proportional to the large parameter $L$. Input stream of water is described by compound Poisson process, and the water cost depends upon current level of water in the dam. The aim of the paper is to choose the parameters of output stream (specifically defined in the paper) minimizing the long-run expenses. The particular problem, where input stream is Poisson and water costs are not taken into account has been studied in [Abramov, \\emph{J. Appl. Prob.}, 44 (2007), 249-258]. The present paper partially answers the question \\textit{How does the structure of water costs affect the optimal solution?} In particular the case of linear costs is studied.

  5. Optimal Power Consumption in a Central Heating System with Geothermal Heat Pump

    DEFF Research Database (Denmark)

    Tahersima, Fatemeh; Stoustrup, Jakob; Rasmussen, Henrik

    2011-01-01

    , lowering the temperature of forward water alleviates energy consumption. The hypothesis is that the minimum water temperature is achieved when at least one of the hydronic heaters in the building works at full capacity. The setpoint of the forward water temperature is found by solving a model based...... optimization problem in a receding finite horizon. The optimization objective is to maintain the local control signal of the largest thermal load near full capacity. The overall control system hierarchy is composed of local PI controllers for each subsystem and an MPC controller which orchestrates the PI...

  6. Cost of district heating using geothermal energy; Ist geothermische Waerme wirtschaftlich?

    Energy Technology Data Exchange (ETDEWEB)

    Oppermann, G. [GRUNEKO AG, Ingenieure fuer Energiewirtschaft, Basel (Switzerland)

    1997-12-01

    The environmental advantages of a district heating network using geothermal energy are obvious. On the other hand utilizing geothermal energy is considered to be very expensive. The goal of this paper is to compare the costs of geothermal energy with other renewable energy sources. Based on the costs of realized plants and projects the following energy sources have been analysed. Geothermal energy, water of tunnel-drainage, waste heat of a sewage disposal platn and waste wood. All plants have a district heating network. The results are a contribution to the actuel discussion about public subsiding of geothermal energy. (orig.) [Deutsch] Die oekologischen Vorteile einer geothermischen Fernwaermeversorgung sind fuer jeden, der Bohrungen in Erwaegung zieht, unschwer erkennbar. Wie steht es aber mit den Kosten einer geothermischen Nutzung? Hier beleben Horrorzahlen wie auch Wunschdenken die Diskussionen. Der Artikel beabsichtigt einen sachlichen Beitrag zu dieser Diskussion uz liefern. Konkrete Bauprojekte im Megawattbereich der GRUNEKO AG werden kostenmaessig nach gleichen Kriterien analysiert und verglichen. Auf goethermischer Seite wird ein Doublettensystem und eine Tunnelwasserwaermenutzung kostenmaessig analysiert. Als Quervergleich werden ebenfalls GRUNEKO-Projekte mit regenerierbaren Energietraegern herangezogen (Holzschnitzelanlage, Klaeranlagenabwaerme, Seewasser-Abkuehlung). Alle Analgen haben Waermeverteilnetze. Die nachgewiesenen Kostendifferenzen zwischen Geothermie und anderen regenerativen Waermversorgungen koennten einen Beitrag leisten zu der gegenwaertig aktuellen `Ueberpruefung staatlicher Foerderungsmassnahmen zugunsten einer verstaerkten Nutzung der Geothermie`. (orig.)

  7. Optimal replacement time estimation for machines and equipment based on cost function

    Directory of Open Access Journals (Sweden)

    J. Šebo

    2013-01-01

    Full Text Available The article deals with a multidisciplinary issue of estimating the optimal replacement time for the machines. Considered categories of machines, for which the optimization method is usable, are of the metallurgical and engineering production. Different models of cost function are considered (both with one and two variables. Parameters of the models were calculated through the least squares method. Models testing show that all are good enough, so for estimation of optimal replacement time is sufficient to use simpler models. In addition to the testing of models we developed the method (tested on selected simple model which enable us in actual real time (with limited data set to indicate the optimal replacement time. The indicated time moment is close enough to the optimal replacement time t*.

  8. Constrained Optimization Problems in Cost and Managerial Accounting--Spreadsheet Tools

    Science.gov (United States)

    Amlie, Thomas T.

    2009-01-01

    A common problem addressed in Managerial and Cost Accounting classes is that of selecting an optimal production mix given scarce resources. That is, if a firm produces a number of different products, and is faced with scarce resources (e.g., limitations on labor, materials, or machine time), what combination of products yields the greatest profit…

  9. Towards Cost and Comfort Based Hybrid Optimization for Residential Load Scheduling in a Smart Grid

    Directory of Open Access Journals (Sweden)

    Nadeem Javaid

    2017-10-01

    Full Text Available In a smart grid, several optimization techniques have been developed to schedule load in the residential area. Most of these techniques aim at minimizing the energy consumption cost and the comfort of electricity consumer. Conversely, maintaining a balance between two conflicting objectives: energy consumption cost and user comfort is still a challenging task. Therefore, in this paper, we aim to minimize the electricity cost and user discomfort while taking into account the peak energy consumption. In this regard, we implement and analyse the performance of a traditional dynamic programming (DP technique and two heuristic optimization techniques: genetic algorithm (GA and binary particle swarm optimization (BPSO for residential load management. Based on these techniques, we propose a hybrid scheme named GAPSO for residential load scheduling, so as to optimize the desired objective function. In order to alleviate the complexity of the problem, the multi dimensional knapsack is used to ensure that the load of electricity consumer will not escalate during peak hours. The proposed model is evaluated based on two pricing schemes: day-ahead and critical peak pricing for single and multiple days. Furthermore, feasible regions are calculated and analysed to develop a relationship between power consumption, electricity cost, and user discomfort. The simulation results are compared with GA, BPSO and DP, and validate that the proposed hybrid scheme reflects substantial savings in electricity bills with minimum user discomfort. Moreover, results also show a phenomenal reduction in peak power consumption.

  10. Optimization of costs of Port Operations in Nigeria: A Scenario For ...

    African Journals Online (AJOL)

    2013-03-01

    Mar 1, 2013 ... This study attempts to optimize the cost of port operations in Nigeria. The quantitative estimates ... its customers at a lower price and also be able to make profits. .... Based On Averages Of Different Kinds Of Cargo. SHIP/PORT ...

  11. Energy cost based design optimization method for medium temperature CPC collectors

    Science.gov (United States)

    Horta, Pedro; Osório, Tiago; Collares-Pereira, Manuel

    2016-05-01

    CPC collectors, approaching the ideal concentration limits established by non-imaging optics, can be designed to have such acceptance angles enabling fully stationary designs, useful for applications in the low temperature range (T concentration factors in turn requiring seasonal tracking strategies. Considering the CPC design options in terms of effective concentration factor, truncation, concentrator height, mirror perimeter, seasonal tracking, trough spacing, etc., an energy cost function based design optimization method is presented in this article. Accounting for the impact of the design on its optical (optical efficiency, Incidence Angle Modifier, diffuse acceptance) and thermal performances (dependent on the concentration factor), the optimization function integrates design (e.g. mirror area, frame length, trough spacing/shading), concept (e.g. rotating/stationary components, materials) and operation (e.g. O&M, tilt shifts and tracking strategy) costs into a collector specific energy cost function, in €/(kWh.m2). The use of such function stands for a location and operating temperature dependent design optimization procedure, aiming at the lowest solar energy cost. Illustrating this approach, optimization results will be presented for a (tubular) evacuated absorber CPC design operating in Morocco.

  12. Integrated emission management strategy for cost-optimal engine-aftertreatment operation

    NARCIS (Netherlands)

    Cloudt, R.P.M.; Willems, F.P.T.

    2011-01-01

    A new cost-based control strategy is presented that optimizes engine-aftertreatment performance under all operating conditions. This Integrated Emission Management strategy minimizes fuel consumption within the set emission limits by on-line adjustment of air management based on the actual state of

  13. Optimizing for confidence—costs and opportunities at the frontier between abstraction and reality

    NARCIS (Netherlands)

    Poss, R.

    2013-01-01

    Is there a relationship between computing costs and the confidence people place in the behavior of computing systems? What are the tuning knobs one can use to optimize systems for human confidence instead of correctness in purely abstract models? This report explores these questions by reviewing the

  14. Robotic lower limb prosthesis design through simultaneous computer optimizations of human and prosthesis costs

    Science.gov (United States)

    Handford, Matthew L.; Srinivasan, Manoj

    2016-02-01

    Robotic lower limb prostheses can improve the quality of life for amputees. Development of such devices, currently dominated by long prototyping periods, could be sped up by predictive simulations. In contrast to some amputee simulations which track experimentally determined non-amputee walking kinematics, here, we explicitly model the human-prosthesis interaction to produce a prediction of the user’s walking kinematics. We obtain simulations of an amputee using an ankle-foot prosthesis by simultaneously optimizing human movements and prosthesis actuation, minimizing a weighted sum of human metabolic and prosthesis costs. The resulting Pareto optimal solutions predict that increasing prosthesis energy cost, decreasing prosthesis mass, and allowing asymmetric gaits all decrease human metabolic rate for a given speed and alter human kinematics. The metabolic rates increase monotonically with speed. Remarkably, by performing an analogous optimization for a non-amputee human, we predict that an amputee walking with an appropriately optimized robotic prosthesis can have a lower metabolic cost – even lower than assuming that the non-amputee’s ankle torques are cost-free.

  15. Evaluation of a low cost wireless heat ratio method system for measuring transpiration

    Science.gov (United States)

    Eiriksson, D.; Boyer, B.; Aishlin, P. S.; Bowling, D. R.

    2016-12-01

    For decades, environmental measurements in remote locations have consisted of sensors hard wired to loggers that send data to central servers via radio, satellite, or cellular telemetry. This model of data collection is effective when all sensors are located in close proximity to the central data logger, such as on a weather station. Frequently, however, in order to adequately capture the spatial heterogeneity associated with environmental processes (e.g., transpiration, soil moisture, or snow depth), it is necessary to install many sensors 10's to 100's of meters from a central data logging station. This presents a practical and financial obstacle when considering the cost of cabling and conduit, in addition to the potential data collection and data quality problems associated with long cable runs. We offer a solution to this persistent challenge with a hybrid datalogging system that combines the power and reliability of Campbell Scientific logging and telemetry equipment with low cost Xbee radios and Arduino based data logging platforms. To evaluate the promise of this hybrid datalogging concept we developed a new generation of low cost, homemade heat ratio sapflux sensors and tested them at a forested site in the Wasatch Mountains, near Salt Lake City, Utah. We present data from this test site, heat ratio method sensor construction details, and example code that merges the capabilities of Arduino and Campbell Scientific datalogging systems.

  16. Power optimization of chemically driven heat engine based on first and second order reaction kinetic theory and probability theory

    Science.gov (United States)

    Zhang, Lei; Chen, Lingen; Sun, Fengrui

    2016-03-01

    The finite-time thermodynamic method based on probability analysis can more accurately describe various performance parameters of thermodynamic systems. Based on the relation between optimal efficiency and power output of a generalized Carnot heat engine with a finite high-temperature heat reservoir (heat source) and an infinite low-temperature heat reservoir (heat sink) and with the only irreversibility of heat transfer, this paper studies the problem of power optimization of chemically driven heat engine based on first and second order reaction kinetic theory, puts forward a model of the coupling heat engine which can be run periodically and obtains the effects of the finite-time thermodynamic characteristics of the coupling relation between chemical reaction and heat engine on the power optimization. The results show that the first order reaction kinetics model can use fuel more effectively, and can provide heat engine with higher temperature heat source to increase the power output of the heat engine. Moreover, the power fluctuation bounds of the chemically driven heat engine are obtained by using the probability analysis method. The results may provide some guidelines for the character analysis and power optimization of the chemically driven heat engines.

  17. Incorporation of Fixed Installation Costs into Optimization of Groundwater Remediation with a New Efficient Surrogate Nonlinear Mixed Integer Optimization Algorithm

    Science.gov (United States)

    Shoemaker, Christine; Wan, Ying

    2016-04-01

    Optimization of nonlinear water resources management issues which have a mixture of fixed (e.g. construction cost for a well) and variable (e.g. cost per gallon of water pumped) costs has been not well addressed because prior algorithms for the resulting nonlinear mixed integer problems have required many groundwater simulations (with different configurations of decision variable), especially when the solution space is multimodal. In particular heuristic methods like genetic algorithms have often been used in the water resources area, but they require so many groundwater simulations that only small systems have been solved. Hence there is a need to have a method that reduces the number of expensive groundwater simulations. A recently published algorithm for nonlinear mixed integer programming using surrogates was shown in this study to greatly reduce the computational effort for obtaining accurate answers to problems involving fixed costs for well construction as well as variable costs for pumping because of a substantial reduction in the number of groundwater simulations required to obtain an accurate answer. Results are presented for a US EPA hazardous waste site. The nonlinear mixed integer surrogate algorithm is general and can be used on other problems arising in hydrology with open source codes in Matlab and python ("pySOT" in Bitbucket).

  18. Cost Optimal Design of a Single-Phase Dry Power Transformer

    Directory of Open Access Journals (Sweden)

    Raju Basak

    2015-08-01

    Full Text Available The Dry type transformers are preferred to their oil-immersed counterparts for various reasons, particularly because their operation is hazardless. The application of dry transformers was limited to small ratings in the earlier days. But now these are being used for considerably higher ratings.  Therefore, their cost-optimal design has gained importance. This paper deals with the design procedure for achieving cost optimal design of a dry type single-phase power transformer of small rating, subject to usual design constraints on efficiency and voltage regulation. The selling cost for the transformer has been taken as the objective function. Only two key variables have been chosen, the turns/volt and the height: width ratio of window, which affects the cost function to high degrees. Other variables have been chosen on the basis of designers’ experience. Copper has been used as conductor material and CRGOS as core material to achieve higher efficiency, lower running cost and compact design. The electrical and magnetic loadings have been kept at their maximum values without violating the design constraints. The optimal solution has been obtained by the method of exhaustive search using nested loops.

  19. Scheduling structural health monitoring activities for optimizing life-cycle costs and reliability of wind turbines

    Science.gov (United States)

    Hanish Nithin, Anu; Omenzetter, Piotr

    2017-04-01

    Optimization of the life-cycle costs and reliability of offshore wind turbines (OWTs) is an area of immense interest due to the widespread increase in wind power generation across the world. Most of the existing studies have used structural reliability and the Bayesian pre-posterior analysis for optimization. This paper proposes an extension to the previous approaches in a framework for probabilistic optimization of the total life-cycle costs and reliability of OWTs by combining the elements of structural reliability/risk analysis (SRA), the Bayesian pre-posterior analysis with optimization through a genetic algorithm (GA). The SRA techniques are adopted to compute the probabilities of damage occurrence and failure associated with the deterioration model. The probabilities are used in the decision tree and are updated using the Bayesian analysis. The output of this framework would determine the optimal structural health monitoring and maintenance schedules to be implemented during the life span of OWTs while maintaining a trade-off between the life-cycle costs and risk of the structural failure. Numerical illustrations with a generic deterioration model for one monitoring exercise in the life cycle of a system are demonstrated. Two case scenarios, namely to build initially an expensive and robust or a cheaper but more quickly deteriorating structures and to adopt expensive monitoring system, are presented to aid in the decision-making process.

  20. BENEFITS AND COSTS IN SELECTING FUEL FOR MUNICIPALITY HEATING SYSTEMS WITH THE ANALYTIC HIERARCHY PROCESS

    Institute of Scientific and Technical Information of China (English)

    Miros(l)aw DYTCZAK; Grzegorz GINDA

    2006-01-01

    Municipal economy problems are of a complex nature. Existing requirements for sustainable development make us apply various criteria while solving these problems. These can, for example,include economic, financial, social and environmental criteria. To handle them effectively,multi-criteria analysis should be applied. Decisions about heat production and delivery systems belong to such multidisciplinary problems. They were usually resolved in the past using classical numerical methodology that took into account only the technical and economic merits of the various alternatives.By applying multi-criteria tools instead it is possible to obtain more realistic results and make more effective decisions. The Analytical Hierarchy Process (AHP) seems to be a good alternative to fill the existing gap between decision-making as it is actually practiced and the traditional methods when applied to selecting district heating (DH) systems. This paper presents such an application. Our application is to select the best heat energy source for a DH system for a medium sized city located in Poland. Our results led to an interesting conclusion with regard to the best heat energy source. Our results suggest that intensifying the effort to make widespread the use of more efficient, but financially more costly, energy sources is the best.