21st International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, Krakow, Polonya, 24 - 27 Haziran 2008, cilt.1, no.1, ss.1177-1183
In this study, firstly, referring the calculated load, firstly, solar energy (SE) and vertical ground source heat pump (GSHP) systems covering space heating and domestic hot water, have been studied separately. Secondly, a hybrid system which is combination of SE and vertical GSHP systems have been investigated in optimum conditions. In the first option, vertical GSHP system can supply both space heating and domestic hot water requirements with a heat pump, which has 26.2 kW capacity. As a second option, it is determined that, with 20 collectors (as villa's roof area allows) SE system can supply 28% of total space heating and domestic hot water requirements. In this option the capacity of heat pump decrease to 16,87 kW. This system which consists of SE and vertical GSHP will be called 'hybrid system' in this paper. For each option, parameters of heat pump have been indicated with tables. With another choice, if SE will be used for domestic hot water only, 68% of domestic hot water during average of the year is possible with 2 collectors. Because of natural gas and LPG are preferred to be used in Istanbul as a conventional system in heating, the heating cost of the villa with natural gas and LPG also calculated and compared with the hybrid system. Hybrid system and natural gas is closer due to the operating cost and LPG more expensive. However due to investment cost, natural gas is the cheapest and hybrid system is the most expensive one. On the other side, government does not supply investment encouragements. Levelized annual total costs for conventional natural gas system, hybrid system and the LPG system are respectively, 0.037 €/kWh, 0.075 €/kWh, 0.076 €/kWh.