Performance analysis of two types of Solar Heating Systems used in buildings under typical North-African climate (Tunisia)

Abstract

The objective of this work is studying the opportunity of using a Solar Heating System, SHS, to prevail the Tunisian households’ air-heating needs by comparing the energetic performances of two solar heating technologies: the SHS with an integrated active layer in the floor and a SHS with an integrated active layer in the wall. The SHS mainly consists of flat-plate solar collectors, a hot water cylinder and an active layer integrated inside the heated building. The study is accomplished by means of TRNSYS 16 simulation software. The investigations of the energetic and thermal performances of the SHS were based on an experimental and simulation studies. A complete model is formulated by means of the TRNSYS simulation program. To validate the TRNSYS model, experimental tests under the typical North-African climate (Tunisia) was performed. The optimization of the SHP performances was achieved by considering the monthly/annual solar fraction, SF. Then, we evaluate the long-term performances of the solar heating system with an integrated active layer in the floor and a solar heating system with an integrated active layer in the wall. The results showed that the optimal sizing of the heating system that allows the supply of a maximum rate of the solar fraction consisted on using 6 m2 area of solar collector, a collector’s mass-flow rate of about 120 kg h−1, a hot water storage cylinder with a capacity of 450 L and a mass flow-rate inside the active layer about 300 kg h−1. The comparison of the long-term performance of the solar heating system showed that the use of the floor as a heat source presented a great potential with a solar fraction of about 78%. It was also found that the use of the solar heating system, SHS, reduced obviously the relative humidity inside the tested room of about 35%.