A solar powered off-grid air conditioning system with natural refrigerant for residential buildings: A theoretical and experimental evaluation

Abstract

Residential air-conditioning units are essential for providing suitable interior comfort in regions experiencing hot climates. Nonetheless, these units contribute significantly to CO₂ emissions in these countries due to their reliance on non-renewable energy sources and the use of environmentally unfriendly working fluids. This research aims to evaluate the feasibility of operating an off-grid solar-powered air-conditioning bed unit using low-GWP refrigerants that can efficiently replace conventional refrigerants. A model was developed to evaluate the vapour compression cycle's energetic and exergetic performance. Various refrigerants were employed as feeds to the mathematical model in order to simulate the unit's performance if environmentally friendly refrigerants supersede the conventional substances. An assembled prototype air-conditioning unit was built to provide cold air to a connected canopy. Two 400 W photovoltaic panels power this system, with battery storage providing electricity to the unit at night. TRNSYS was used to evaluate the batteries' energy storage capability, whilst Integrated Environmental Solutions Virtual Environment (IESVE) was used to estimate the amount of solar energy required to power the unit. On the basis of the energetic and exergetic findings, R290 and R600a have demonstrated their suitability as replacements for conventional refrigerants. In comparison to R134a, the system showed a 2.42% improvement in COP when using R290. This improvement was accompanied by a reduction in input work by 2.31% and an increase in exergetic efficiency by 2.37%. This paper provides a guideline for analytical design, combined with a coherent process system. This offers an excellent solution to the very real problems of major energy consumption in warm countries, combining a renewable energy source with an eco-friendly air-conditioning cycle.