DESIGN AND SIMULATION OF SOLAR THERMAL COOLING AND HEATING SYSTEM

Abstract

The cooling and heating systems have become indispensable part of our life. These systems are one of the major contributors to the overall energy consumption. The heating. ventilation and cooling (HVAC) market continues to rise since last few decades. Undoubtedly. heating and cooling systems add enormously to the CO2 emission. Fossil fuel depletion also is an issue associated with the fossil fuel based energy. With the concerns over usage of conventional electricity the solar powered cooling and heating systems have evolved which are driven by thermal input. There are many solar based cooling systems viz. (i) absorption, (ii) adsorption. (iii) desiccant and (iv) ejector systems. The literature review shows that among the various solar refrigeration methods absorption refrigeration has been extensively studied and preferred. Present work focuses on solar powered cooling and heating system based on absorption chiller. A solar thermal absorption system for cooling and heating system has been theoretically designed for Students' Computer Laboratory, Alternate Hydro Energy Center at lIT Roorkee, India. Among the two popular refrigerant pairs NH3-water and LiBr-water, LiI3r-water has been chosen for the absorption chiller because it can utilize the thermal energy at relatively very low temperatures to produce cooling. The system in consideration is powered by hot water from flat plate collector field. The solar data and meteorological information have been generated with the guidelines from ASI-IRAE Handbook Fundamentals - 2013. The cooling load has been calculated using the radiant time series (RTS) method which was 8.77 kW at the peak. The absorption cycle was simulated in spreadsheet program after knowing the cooling demand and the heat input required to the system was obtained. It was seen that to meet a peak cooling demand of 8.77 kW, the flat plate solar collector field required was 54 m2. The optimum volume of hot water storage tank was suggested to be integrated with the system. The system is able to meet the heating requirement in winter by directly supplying the hot water and by heating the air. A COP of 0.82 was achieved in the present study and it was seen that the system required minimal amount of electricity to pump the working fluid.