Experimental study of a combined biomass and solar energy‑based fully grid‑independent air‑conditioning system

Abstract

In this paper, a small-scale triple-hybrid air-conditioning system operated by biomass and solar energy resources is experimentally investigated. Comparisons with EnergyPlus simulations are also shown. Experiments reveal the necessity of system’s pull down because of inequality of heat transfer within the chiller. The biomass gasifer driving an electrical generator in combination with solar collector fulfls the total energy requirements that make the present system triple-hybrid in nature. An air-cooled lithium bromide–water operated absorption chiller of 4.06 kW rated capacity is fabricated and tested. The biomass-generated electricity enables to reduce the grid dependency of the system to fulfl net-zero-energy criterion. The system is tested under diferent generator temperature ranges (60 °C, 70 °C and 80 °C) and lithium bromide concentrations (54% and 58%) in water. With 54% concentration, this system operates up to 64.8% of nominal capacity with average coeffcient of performance ranging between 0.14 and 0.19. However, with 58% concentration, up to 85.1% of its nominal capacity along with the coefcient of performance ranging between 0.19 and 0.25 can be acquired. The system caters the maximum load with the highest coefcient of performance of 0.34. Rise in the generator temperature improves the cooling capacity, coefcient of performance, shows quicker response of the system and drops the fnally-attained room air temperature. Economic analysis reveals the payback time for the present system to lie in the range of 9–12 years. Finally, emission analysis reveals considerable possibility of greenhouse gas reduction in an afordable manner.