Performance comparison of six solar-powered air-conditioners operated in five places

Six solar-powered air-conditioners, based on four principles (LiBr + H2O liquid sorption, silicagel + water solid sorption, BaCl2 + NH3 thermochemical reaction, and desiccant + humid air open cycles) have been operated in five places (from the low-altitude Alps to a tropical island including Mediterranean Sea shore). A common experimentation procedure was applied over months, except for some cases, and during several years. Data were recorded, gathered, and analyzed similarly for the six units. Is established a sound framework based on relevant quantities, some non-dimensional and others dimensional but referred to relevant scales, with the purpose that direct comparison of results is sensible. Similarly, are defined the sub-units to be considered for further analysis. This framework is applied to (i) data averaged over long periods, and (ii) data obtained on one single day with given insolation. Comprehension obtained from comparison in that framework gives access to notions as different as (i) fundamental differences between systems, (ii) aging of components, and (iii) non-linearity of the basic operation of such solar-powered units. The theoretical analysis of this non-linearity is developed. The framework established in this article could thus be used for comparing other solar-powered processes.

► Comparative study of six units, in five places, with four sorption techniques.
► Experimental seasonal solar COP for air-conditioning ranges from 0.08 to 0.20.
► Liquid sorption seems to be more efficient than other principles.
► Effective electricity consumption is severely affected by initial design choices.
► Aging of solar collectors may also be a real issue.