Model Development and Transient Seasonal Performance Analysis of a Solar Space Heating System under Climate Conditions of PAKISTAN

The model-based transient system simulation approach is very effective for a performance assessment of solar systems under various climate conditions. In the current study, a hybrid array of flat and evacuated tube collector was analyzed for space heating using a panel radiator for a room with a volume of 1600 ft3 at different flow rates. A detailed model is developed in TRNSYS that consists of a hybrid collector array, storage tank and pumping device along with a building load component. Using transient simulation, the performance of the hybrid solar space heating system was analyzed from December to February for the subtropical climate of Taxila, Pakistan. The results revealed that at flow rates of 350, 450 and 550 kg/h, the range of temperature gain of the hybrid collector array vary from 2.8to 15.4 °C, 1.7 to 11.6 °C and 1.2 to 9.2 °C from December to February, respectively, whereas the variation in efficiencies are 25.2 to 70.4%, 22 to 70.2% and 18.4 to 68.1% for December, January and February, respectively. In addition, it is observed that about 5.29 and 7.97% better seasonal efficiency is achieved for flow rate 350 kg/h as compared to 450 and 550 kg/h. The resulted room temperature varies from 22.3 to 26.8 °C, 22.2 to 27 °C and 22.4 °C to 30 °C for December, January and February to ensure desired thermal comfort. Overall, the results show that solar heating systems are viable to achieve the thermal comfort in winter and thus can significantly reduce gas consumption in the country.