Pages: 9-23

Abstract

Among the thermal applications of solar energy, hybrid solar systems have attracted greater attention in the world both technically and economically in comparison with other thermal applications of solar energy. The reason for this preference is that these systems need a medium temperature to provide hot water and solar heat, and this temperature can be provided by using a flat collector which is cheaper than any other collector. Various hybrid solar systems are used in residential buildings whose financial and thermal efficiency depends on different factors. One of the most important factors affecting the performance of a system is the type of fuel used in the building. This study aims to investigate the efficiency of energy-saving by a hybrid solar system compared with the fossil fuel heating and the analysis of the thermal and financial performance of a floor heating system. In this research, a typical building (i.e., a bungalow considering the abundance of this building in Iran) in Tehran has been considered. This building is studied with three systems, and the thermal load, equipment sizing, gas, diesel, and energy consumption and other energy factors are investigated in each case. For this purpose, the typical building was modeled in different configurations by DesignBuilder and Carrier software. Different study states include using a hybrid solar system, fossil fuel heating system using natural gas package, fossil fuel heating system with engine room (powerhouse) and diesel fuel. Finally, the annual savings rate of gas and diesel consumption and Payback period are compared with cases mentioned above and the case of fossil fuels alone. The results show that a combination of the solar system, fossil power system, and natural gas is not very affordable enough for buildings with natural gas pipelines; however, a combination of the solar system is economically feasible for buildings with diesel fuel and central heating. Furthermore, from a global perspective, it is also considered that, if fuel prices, including natural gas and diesel, are considered to be equivalent to their export prices, the payback period will be economically justifiable.