Performance of a Solar Desiccant Cooling System

1988 ◽  
Vol 110 (3) ◽  
pp. 165-171 ◽  
Author(s):  
George O. G. Lo¨f ◽  
Gerald Cler ◽  
Thomas Brisbane

A solar desiccant cooling system was operated at the Solar Energy Applications Laboratory, Colorado State University, throughout the 1986 summer. The system comprises an American Solar King fresh air heating/desiccant evaporative cooling unit, a Sunmaster evacuated tube solar collector, hot water solar storage tank, auxiliary electric boiler, controls, and accessories. The cooling unit is operated in the ventilation mode, fresh air being dried in a rotating desiccant matrix, and cooled by heat exchange and evaporative cooling. Return air is used as a cooling medium in a rotating heat exchange matrix, heated by solar energy in a heat exchange coil, and discarded through the rotating desiccant bed. The solar-driven system provided over 90 percent of the seasonal cooling requirements in an experimental, residence type building at average COP levels of 1.0 and solar collection efficiencies of 50 percent when supplied with solar heated water at temperatures of 50 to 65° C. Detailed operating results, including total and average solar cooling provided, coefficients of performance, and overall solar cooling performance ratios are presented.

2018 ◽  
Vol 1 (2) ◽  
pp. 40-51 ◽  
Author(s):  
Muhammad Burhan ◽  
Muhammad Wakil Shahzad ◽  
Kim Choon Ng

Standalone power systems have vital importance as energy source for remote area. On the other hand, a significant portion of such power production is used for cooling purposes. In this scenario, renewable energy sources provide sustainable solution, especially solar energy due to its global availability. Concentrated photovoltaic (CPV) system provides highest efficiency photovoltaic technology, which can operate at x1000 concentration ratio. However, such high concentration ratio requires heat dissipation from the cell area to maintain optimum temperature. This paper discusses the size optimization algorithm of sustainable cooling system using CPVT. Based upon the CPV which is operating at x1000 concentration with back plate liquid cooling, the CPVT system size is optimized to drive a hybrid mechanical vapor compression (MVC) chiller and adsorption chiller, by utilizing both electricity and heat obtained from the solar system. The electrolysis based hydrogen is used as primary energy storage system along with the hot water storage tanks. The micro genetic algorithm (micro-GA) based optimization algorithm is developed to find the optimum size of each component of CPVT-Cooling system with uninterrupted power supply and minimum cost, according to the developed operational strategy. The hybrid system is operated with solar energy system efficiency of 71%.


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.


2016 ◽  
Author(s):  
I. P. Koronaki ◽  
E. G. Papoutsis ◽  
M. T. Nitsas

Solar cooling systems offer a reliable and environmentally friendly alternative to conventional electrically driven vapor compression cooling units. Air conditioning systems powered by solar energy are very attractive because they have zero ozone depletion and global warming potential, their operational cost is low and they do not burden the electrical network during summer months. In this study, the installation of a solar cooling system in various Greek cities is examined. The system utilizes a single-stage, two-bed silica gel-water adsorption chiller driven by heat produced by solar collectors. A lumped parameter model is used to simulate the performance of the adsorption chiller. The optimum tilt of the solar collectors is calculated for each examined city in order for the collected solar energy to be maximized during the summer period (April to September). The climatic data are taken from the technical notes of Greek Regulation for Buildings Energy Performance. Then, using the f-chart cooling method the necessary collectors’ surface area is estimated for every examined city and for different types of flat plate collectors (including advanced flat plate, simple flat plate and hybrid photovoltaic thermal collectors).


2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Tanzeen Sultana ◽  
Graham L. Morrison ◽  
Robert Taylor ◽  
Gary Rosengarten

In this paper, simulation of a linear Fresnel rooftop mounted concentrating solar collector is presented. The system is modeled with the transient system (trnsys) simulation program using the typical meteorological year file containing the weather parameters of four different cities in Australia. Computational fluid dynamics (CFD) was used to determine the heat transfer mechanism in the microconcentrating (MCT) collector. Ray trace simulations using soltrace (NREL) were used to determine optical efficiency. Heat loss characteristics determined from CFD simulation were utilized in trnsys to assess the annual performance of the solar cooling system using an MCT collector. The effect of the different loads on the system performance was investigated, and from trnsys simulations, we found that the MCT collector achieves a minimum 60% energy saving for both domestic hot water usage and high temperature solar cooling and hot water applications.


2015 ◽  
Vol 70 ◽  
pp. 486-494 ◽  
Author(s):  
Jeremy P. Osborne ◽  
Paul Kohlenbach ◽  
Uli Jakob ◽  
Johan Dreyer ◽  
Jamey Kim

2021 ◽  
Vol 312 ◽  
pp. 08014
Author(s):  
Giovanni Brumana ◽  
Giuseppe Franchini ◽  
Elisa Ghirardi

The paper presents a complete solar cooling comparison. A detailed model of a tertiary sector building has been evaluated in three locations (Riyadh, Abu Dhabi, and Palermo) and coupled with four solar cooling systems: two solar thermal cooling systems (Li-Br absorption chiller and adsorption chiller), a solar Desiccant Evaporative Cooling system and a solar electric cooling (Photovoltaic coupled with Compression chiller). A multi-variable optimization procedure selects the optimal size of each component. The results show that the solar cooling system based on absorption chiller satisfied the cooling demand regardless of the site location whilst the performance of the Desiccant Evaporative Cooling system is dramatically affected by ambient conditions. The electric solar cooling option shows the best overall efficiency and appears a costeffective solution despite the high cost of the storage system.


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