scholarly journals Thermal Performance Analysis of an Absorption Cooling System Based on Parabolic Trough Solar Collectors

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2679 ◽  
Author(s):  
Jiangjiang Wang ◽  
Rujing Yan ◽  
Zhuang Wang ◽  
Xutao Zhang ◽  
Guohua Shi

Solar radiation intensity significantly influences the cooling loads of building, and the two are correlated and accorded to a certain extent. This study proposes a double effect LiBr–H2O absorption cooling system based on the parabolic trough collector (PTC) of solar heat energy. Thermodynamic models including PTC and absorption chiller are constructed, and their accuracy is verified by comparing the simulation results and the experimental data. Subsequently, the impact of variable design parameters on the thermodynamic performance is analyzed and discussed. The analysis of a solar cooling system in a hotel case study is related to its operation in a typical day, the average coefficient of performance of the absorption chiller is approximately 1.195, and the whole solar cooling system achieves 61.98% solar energy utilization efficiency. Furthermore, the performance comparison of a solar cooling system in different types of building indicates that higher matching and a higher correlation coefficient between the transient solar direct normal irradiance and cooling load is helpful in decreasing the heat loss and improving systemic performance. The solar cooling system in the office building exhibits a correlation coefficient of approximately 0.81 and achieves 69.47% systemic thermal efficiency.

Author(s):  
Ru Yang ◽  
Yi-Ying Chiu

The performance of an absorption solar cooling system operated under Taiwan climate is studied via computer simulation. Solar energy is utilized as the driving energy for an absorption cooling system, and a TRNSYS computer code is employed to simulate the operation of the system. Climate data in TMY2 form for five major cities of Taiwan are input to the simulation program. Also system operating parameters of solar collector area and the size of the storage tank are varied to study there effects on the system performance. This research provides computer simulation data for the monthly solar fraction (f) as well as the seasonal solar fraction (F) for the absorption solar cooling system operated under the climate of the major cities in Taiwan. The data can provide the design needs.


Author(s):  
Jan Albers ◽  
Giovanni Nurzia ◽  
Felix Ziegler

The efficient operation of a solar cooling system strongly depends on the chiller behaviour under part-load conditions since driving energy and cooling load are never constant. For this reason the performance of a single stage, hot water driven 30 kW H2O/LiBr-absorption chiller employed in a solar cooling system with a field of 350 m2 evacuated tube collectors has been analysed under part-load conditions with both simulations and experiments. A simulation model has been developed for the whole absorption chiller (Type Yazaki WFC-10), where all internal mass and energy balances are solved. The connection to the external heat reservoirs of hot, chilled and cooling water is done by lumped and distributed UA-values for the main heat exchangers. In addition to an analytical evaporator model — which is described in detail — experimental correlations for UA-values have been used for condenser, generator and solution heat exchanger. For the absorber a basic model based on Nusselt theory has been employed. The evaporator model was developed taking into account the distribution of refrigerant on the tube bundle as well as the change in operation from a partially dry to an overflowing evaporator. A linear model is derived to calculate the wetted area. The influence of these effects on cooling capacity and COP is calculated for three different combinations of hot and cooling water temperature. The comparison to experimental data shows a good agreement in the various operational modes of the evaporator. The model is able to predict the transition from partially dry to an overflowing evaporator quite well. The present deviations in the domain with high refrigerant overflow can be attributed to the simple absorber model and the linear wetted area model. Nevertheless the results of this investigation can be used to improve control strategies for new and existing solar cooling systems.


Paper The energy shortage in today's world has shifted the view of researchers to the optimal use of available energy, and experts from energy research centers have always taken steps to achieve this important issue. In the present study, the focus is on the simulation of a mixed system which, in addition to generating power, uses the heat dissipated from its chimney to produce cooling using an absorption chiller. This mixed system is simulated in EES software. The performance of the mixed system is examined in three different views, and in each view, the values of cold loads are obtained from the absorption chiller.


2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Jan Albers ◽  
Giovanni Nurzia ◽  
Felix Ziegler

The efficient operation of a solar cooling system strongly depends on the chiller behavior under part load conditions, since driving energy and cooling load are never constant. For this reason, the performance of a single stage, hot water driven 30 kW H2O/LiBr-absorption chiller employed in a solar cooling system with a field of 350 m2 evacuated tube collector has been analyzed under part load conditions with both simulations and experiments. A simulation model has been developed for the whole absorption chiller (Type Yazaki WFC-10), where all internal mass and energy balances are solved. The connection to the external heat reservoirs of hot, chilled, and cooling water is done by lumped and distributed UA values for the main heat exchangers. In addition to an analytical evaporator model—which is described in detail—experimental correlations for UA values have been used for the condenser, generator, and solution heat exchanger. For the absorber, a basic model based on the Nusselt theory has been employed. The evaporator model was developed, taking into account the distribution of refrigerant on the tube bundle, as well as the change in operation from a partially dry to an overflowing evaporator. A linear model is derived to calculate the wetted area. The influence of these effects on cooling capacity and coefficient of performance (COP) is calculated for three different combinations of hot and cooling water temperature. The comparison to experimental data shows a good agreement in the various operational modes of the evaporator. The model is able to predict the transition from partially dry to an overflowing evaporator quite well. The present deviations in the domain with high refrigerant overflow can be attributed to the simple absorber model and the linear wetted area model. Nevertheless, the results of this investigation can be used to improve control strategies for new and existing solar cooling systems.


2018 ◽  
Vol 49 ◽  
pp. 02009
Author(s):  
Elieser Tarigan

The possibility of solar cooling technologies is simulated and discussed in this work. Cooling system application for a six-floor university building in Surabaya Indonesia was taken as a case study. Two different solar technologies systems were designed and compared: (i) photovoltaic powered cooling system, and (ii) solar thermal absorption cooling system. Economic analysis was carried out based on the economic key-figures as well as the CO2 emission analysis. Based on the results gained in the profitability analysis, the most economically feasible system is solar thermal absorption cooling system due to the good agreement between solar radiation andcooling demand. Besides, this systems allows the maximum CO2 emissions savings.


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