Solar combi-systems: a new solution for heating buildings

Subject Areas : environmental management

Morteza Khalaji Asadi ¹ (Associate Professor ,Faculty of Environment and Energy, Science and Research Campus ,Azad University of Tehran)
Zahra Abedi ² (Faculty of Energy and Environment, Science and Research Campus ,Azad University of Tehran)
Nima Sharee ³ (Faculty of Energy and Environment, Science and Research Campus ,Azad University of Tehran)

Received: 2007-09-01 Accepted : 2007-12-01 Published : 2009-09-23

Keywords: Social costs, Flat-plate collector, solar combi-systems, heating load, Payback Period,

Abstract :

Solar combi-systems have attracted more attention technologically and economically compared with the other thermal applications of the solar energy in the world. The reason why these systems are preferred for the provision of hot water and solar heating is that they need a medium temperature which can be supplied by flat-plate collectors and at a lower cost than that of other types of collectors. In this paper, first the thermal loads of residential apartments (in two cases: with common materials and with materials dictated by the national rules of construction) in Hamedan and Karaj have been computed. Then, suitable solar combi-systems have been designed for each apartment. Subsequently, the rate of thermal energy that can be provided by this system and windows has been calculated. In the next step, considering the heating energy needed by building and studying the expense-efficiency curve of the solar combi-system, the number of solar flat-plate collectors has been calculated, and considering the effect of solar panels shadow and the space limitation of the roof, a hybrid (fossil-solar) system has been proposed. The results show that the average solar energy which can be used varies from 15 1o 45 percents in the cold months of the year. Consequently, considering the annual fuel savings and also the reduction of social costs in cold regions using the solar combi-system as well as the international price of energy, about 43 million Rials will be saved in fuel costs so that the initial high investment expenses will be returned in less than two years. In the same way, about 10 million Rials will be saved in fuel costs in temperate regions; therefore, the initial investment expenses will be returned in four years