An experimentally validated thermodynamic model of a domestic-scale solar-cooling system based on an ammonia-water diffusion-absorption refrigeration (DAR) cycle is presented. The model combines sub-component descriptions of a DAR unit and a suitably sized (matched) solar-collector array, which are validated separately;
outdoor tests are performed on an evacuated-tube (ET) collector
over a range of solar-irradiance conditions, while a 150-W (nominal
rating) DAR unit is tested in the laboratory with a thermal input provided by controlled electrical heaters. A COP of 0.2 is reported for the DAR
unit when operating with a generator temperature of 155 °C and a system charge pressure of 20.7 bar. Using the experimentally
validated solar-cooling system model, it is found that the area
of the collector array required to power the system depends strongly on the type of collector. Annual simulations are also performed
in various geographical regions order to predict the system’s
cooling output. It is found that a single DAR unit with a 3-m2 ET array
has the potential to provide 150-200 kWh per year of cooling
in a southern European climate, which amounts approximately to the per capita demand for space cooling in residential dwellings in the
same region.