Exergy analysis and optimization of a solar-assisted heat pump

Núñez, M. Picón

doi:10.1016/s0360-5442(97)00079-0

Cited by 76 publications

(24 citation statements)

References 4 publications

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“…It is obvious from Table V that the exergy rate and the second law efficiency in each component are calculated as a function of thermodynamic parameters. Using Equation (13), the second law efficiency is determined for each component given in Table V. By comparison, in a study performed by Reyes et al [19], the exergy losses of the component are found as follows: the exergy loss of the compressor is 0.104 kW; the exergy loss of the condenser is 0.663 kW; the exergy loss of the collector-evaporator is 3.518 kW. It may be concluded that the exergy loss values obtained in the present study are fairly close to those reported by Reyes et al [19].…”

Section: T ð8cþmentioning

confidence: 99%

“…Using Equation (13), the second law efficiency is determined for each component given in Table V. By comparison, in a study performed by Reyes et al [19], the exergy losses of the component are found as follows: the exergy loss of the compressor is 0.104 kW; the exergy loss of the condenser is 0.663 kW; the exergy loss of the collector-evaporator is 3.518 kW. It may be concluded that the exergy loss values obtained in the present study are fairly close to those reported by Reyes et al [19]. The largest exergy loss occurs in the condenser (0.89 kW) followed by the evaporator (0.18 kW), the expansion valve (0.04 kW) as confirmed by Pridasawas et al [20].…”

Section: T ð8cþmentioning

confidence: 99%

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Exergetic performance evaluation of heat pump systems having various heat sources

Di̇ki̇ci̇

Akbulut

2008

Int. J. Energy Res.

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SUMMARYIn this study heat pump systems having different heat sources were investigated experimentally. Solar-assisted heat pump (SAHP), ground source heat pump (GSHP) and air source heat pump (ASHP) systems for domestic heating were tested. Additionally, their combination systems, such as solar-assisted-ground source heat pump (SAGSHP), solar-assisted-air source heat pump (SAASHP) and ground-air source heat pump (GSASHP) were tested. All the heat pump systems were designed and constructed in a test room with 60 m 2 floor area in Firat University, Elazig (38:418N; 39:148E), Turkey. In evaluating the efficiency of heat pump systems, the most commonly used measure is the energy or the first law efficiency, which is modified to a coefficient of performance for heat pump systems. However, for indicating the possibilities for thermodynamic improvement, inadequate energy analysis and exergy analysis are needed. This study presents an exergetic evaluation of SAHP, GSHP and ASHP and their combination systems. The exergy losses in each of the components of the heat pump systems are determined for average values of experimentally measured parameters. Exergy efficiency in each of the components of the heat pump systems is also determined to assess their performances. The coefficient of performance (COP) of the SAHP, GSHP and ASHP were obtained as 2.95, 2.44 and 2.33, whereas the exergy losses of the refrigerant subsystems were found to be 1.342, 1.705 and 1.942 kW, respectively. The COP of SAGSHP, SAASHP and GSASHP as multiple source heat pump systems were also determined to be 3.36, 2.90 and 2.14, whereas the exergy losses of the refrigerant subsystems were approximately 2.13, 2.996 and 3.113 kW, respectively. In addition, multiple source heat pump systems were compared with single source heat pump systems on the basis of the COP. Exergetic performance coefficient (EPC) is introduced and is applied to the heat pump systems having various heat sources. The results imply that the functional forms of the EPC and first law efficiency are different. Results show that Ex loss;total becomes a minimum value when EPC has a maximum value.

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Section: T ð8cþmentioning

confidence: 99%

Section: T ð8cþmentioning

confidence: 99%

Exergetic performance evaluation of heat pump systems having various heat sources

Di̇ki̇ci̇

Akbulut

2008

Int. J. Energy Res.

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“…The effects of the mass flow rates and inlet temperatures of both hot and cold working fluids on entropy generation and exergy loss in the heat exchanger were discussed based on a distributed-parameter mathematical model. Reyes et al [9] carried out an exergy analysis which was equivalent to entropy generation analysis for a solar-assisted heat pump. A methodology for determining the condensing and evaporating temperature of the working fluid was proposed and an optimal condensing temperature was obtained.…”

Section: Introductionmentioning

confidence: 99%

Optimisation of Direct Expansion (DX) Cooling Coils Aiming to Building Energy Efficiency

Liang¹,

Yang²,

Chan³

et al. 2015

JBCPR

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Efficient Air Conditioning (A/C) system is the key to reducing energy consumption in building operation. In order to decrease the energy consumption in an A/C system, a method to calculate the optimal tube row number of a direct expansion (DX) cooling coil for minimizing the entropy generation in the DX cooling which functioned as evaporator in the A/C system was developed. The optimal tube row numbers were determined based on the entropy generation minimization (EGM) approach. Parametric studies were conducted to demonstrate the application of the analytical calculation method. Optimal tube row number for different air mass flow rates, inlet air temperatures and sensible cooling loads were investigated. It was found that the optimal tube row number of a DX cooling coil was in the range of 5 -9 under normal operating conditions. The optimal tube row number was less when the mass flow rate and inlet air temperature were increased. The tube row number increased when the sensible cooling load was increased. The exergy loss when using a non-optimal and optimal tube row numbers was compared to show the advantage of using the optimal tube row number. The decrease of exery loss ranged from around 24% to 70%. Therefore the new analytical method developed in this paper offers a good practice guide for the design of DX cooling coils for energy conservation.

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“…This combined system could operate more efficiently under a wide range of weather conditions and for more hours each day. Abundant work, both theoretical and experimental, has been done on solar assisted-heat pump systems [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. The results presented show that the thermal efficiency of the collector which acts as the heat source of a heat pump system is high because of the lower temperature difference between the collector and the environment, while the heat pumps' annual and seasonal performance were increased by increasing the heat source temperature of the heat pumps.…”

Section: Introductionmentioning

confidence: 99%

Building Space Heating with a Solar-Assisted Heat Pump Using Roof-Integrated Solar Collectors

Zhang

Zhu

2011

Energies

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A solar assisted heat pump (SAHP) system was designed by using a roof-integrated solar collector as the evaporator, and then it was demonstrated to provide space heating for a villa in Tianjin, China. A building energy simulation tool was used to predict the space heating load and a three dimensional theoretical model was established to analyze the heat collection performance of the solar roof collector. A floor radiant heating unit was used to decrease the energy demand. The measurement results during the winter test period show that the system can provide a comfortable living space in winter, when the room temperature averaged 18.9 °C. The average COP of the heat pump system is 2.97 and with a maximum around 4.16.Keywords: building integration; solar roof tiles; heat pump; building space heating; simulation

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Exergy analysis and optimization of a solar-assisted heat pump

Cited by 76 publications

References 4 publications

Exergetic performance evaluation of heat pump systems having various heat sources

Exergetic performance evaluation of heat pump systems having various heat sources

Optimisation of Direct Expansion (DX) Cooling Coils Aiming to Building Energy Efficiency

Building Space Heating with a Solar-Assisted Heat Pump Using Roof-Integrated Solar Collectors

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