OPERATING RESULTS FOR A SOLAR COOLING SYSTEM USING A COMBINED SINGLE-DOUBLE EFFECT ABSORPTION CHILLER

A solar cooling system with an optimized air-cooled double-effect water/LiBr absorption machine is proposed as a sustainable alternative to meet cooling demands in dry hot climates. This system allows eliminating the cooling towers in those regions of the planet where water is scarce. This work analyses the environmental benefits of this air-cooled system, as well as its environmental foot-prints, compared to a solar water-cooled single effect. In this regard, a methodology has been applied to calculate the annual saving in water consumption produced in a case study: a hospital located in Almer?a, in South of Spain. Further-more, the reduction in energy consumption and CO2 emissions is also quantified since this machine can be driven by solar energy and with higher efficiency than those of single effect.

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Simulation and Experimental Analysis of a Solar Driven Absorption Chiller With Partially Wetted Evaporator

ASME 2008 2nd International Conference on Energy Sustainability, Volume 2 ◽

10.1115/es2008-54102 ◽

2008 ◽

Author(s):

Jan Albers ◽

Giovanni Nurzia ◽

Felix Ziegler

Keyword(s):

Cooling System ◽

Cooling Water ◽

Hot Water ◽

Absorption Chiller ◽

Efficient Operation ◽

Part Load ◽

Solar Cooling ◽

Wetted Area ◽

Solar Cooling System ◽

Load Conditions

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.

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Case study of a solar cooling system with a small NH 3 /H2 O absorption chiller

The Solar Cooling Design Guide - Case Studies of Successful Solar Air Conditioning Design ◽

10.1002/9783433606841.ch3 ◽

2017 ◽

pp. 19-66

Author(s):

Daniel Neyer ◽

Jacqueline Neyer ◽

Alexander Thür ◽

Wolfgang Streicher ◽

Bettina Nocke

Keyword(s):

Cooling System ◽

Absorption Chiller ◽

Solar Cooling ◽

Solar Cooling System

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Technical-Economic Analysis of Steam Double Effect Absorption Chiller-Heaters Equipped with Solar Heat Pipe System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.465-466.327 ◽

2013 ◽

Vol 465-466 ◽

pp. 327-334

Author(s):

Morteza Khalaji Assadi ◽

Hamidreza Akhavan Armaki ◽

Mahmoud Zendeh Del

Keyword(s):

Economic Analysis ◽

Heat Pipe ◽

Cooling System ◽

Double Effect ◽

Coefficient Of Performance ◽

Absorption Chiller ◽

Solar Heat ◽

Pipe System ◽

Break Even Point ◽

Solar Cooling System

The aim of this research is to indicate a steam double effect chiller-heater equipped with solar heat pipe in a certain space with the area of 975 m2 located in Tehran, which is currently equipped with a direct-fired single effect absorption chiller-heater. Thereafter , the most obvious differences of the two chiller-heater systems are compared: the solar cooling system increases coefficient of performance as high as 0.54, decreases CO2 dissemination by 829 tons in each year, and reduces energy consumption by 1552.42 MWh/Yr. Economic analysis of the two systems using break-even-point showed that the use of solar system is attractive in applications that have excess thermal energy, and the conversion of this energy to higher value energy markets is to be more profitable than absorption gas-fired system from 13th year on. Keywords: Technical-economic analysis, energy optimization, solar chiller, absorption chiller-heater, solar heat pipe.

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Simulation and Experimental Analysis of a Solar Driven Absorption Chiller With Partially Wetted Evaporator

Journal of Solar Energy Engineering ◽

10.1115/1.4000331 ◽

2010 ◽

Vol 132 (1) ◽

Cited By ~ 4

Author(s):

Jan Albers ◽

Giovanni Nurzia ◽

Felix Ziegler

Keyword(s):

Cooling System ◽

Cooling Water ◽

Hot Water ◽

Absorption Chiller ◽

Efficient Operation ◽

Part Load ◽

Solar Cooling ◽

Wetted Area ◽

Solar Cooling System ◽

Load Conditions

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.

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Simulation of solar cooling system based on variable effect LiBr-water absorption chiller

Renewable Energy ◽

10.1016/j.renene.2017.06.069 ◽

2017 ◽

Vol 113 ◽

pp. 907-914 ◽

Cited By ~ 22

Author(s):

Z.Y. Xu ◽

R.Z. Wang

Keyword(s):

Water Absorption ◽

Cooling System ◽

Absorption Chiller ◽

Variable Effect ◽

Solar Cooling ◽

Solar Cooling System

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

Energies ◽

10.3390/en11102679 ◽

2018 ◽

Vol 11 (10) ◽

pp. 2679 ◽

Cited By ~ 9

Author(s):

Jiangjiang Wang ◽

Rujing Yan ◽

Zhuang Wang ◽

Xutao Zhang ◽

Guohua Shi

Keyword(s):

Correlation Coefficient ◽

Cooling System ◽

Utilization Efficiency ◽

Design Parameters ◽

Parabolic Trough ◽

Absorption Chiller ◽

Solar Cooling ◽

Absorption Cooling ◽

Solar Cooling System ◽

Absorption Cooling System

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.

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