Performance assessment of residential scale solar driven adsorption cooling system in hot arid areas and gained operational experiences

This study present performance assessment of residential scales solar thermal driven adsorption cooling system as well as the gained operational experiences installed at Assiut, Egypt (hot arid and dusty climate) and in operation since summer 2012. The system consists of the following main components: evacuated tube solar collector field with apparent area of 36 m² modified with back high reflective parabolic surface under the vacuum tubes, adsorption chiller of 8 kW nominal cooling capacity (silica gel-water), hot water storage buffer of 1.8 m³ effective volume and cold water storage tank of and 1.2 m³ effective volume, 34 kW or 50 kW capacity wet cooling tower, two 4.5 kW capacity fan-coils, energy saving pumps, expansion tanks, backup gas water heater, controllers, measuring sensors and data acquisition system with impeded controller. The results show that: The daily solar collector efficiency during the reported period of system operation ranged from about 50 % to 78 %. The chiller average COP was ranged from 0.4 to 0.64 with average chilling power ranged from 3. 6 to 6.42 kW, the average cooling water temperature outlet from the cooling tower ranged from 31.4 °C to 23.4 °C and the average chilled outlet water temperature from the chiller ranged from 19 °C to 12.12 °C. For the cooling session of 2012 cooling water outlet temperature from the cooling tower of 31 °C, which is higher, the city water at temperature of 27.5 °C was used to cool the chiller directly and this experiment leads to enhancement the chiller COP by 40 % and the chilling capacity of the chiller by 17 %. In the cooling session of 2014 a 50 kW cooling capacity wet cooling tower is integrated in the system and the measurements show that the outlet cooling tower water temperature is about 23.4 °C at ambient air dry bulb of 35.7 °C and Wet Bulb temperature of about of 19 °C. Consequently, the chiller cooling capacity reach around 6.42 kW and COP was about 0.64 and chilled water temperature was 15 °C. As the heat rejection from the system has a major impact on the system performance in hot arid area, therefore, the re-cooling system should be based on alternative heat sink recourses techniques.