Heat pump application integrated to bored piles and its economic analysis

Petrol reserves, which are known to be one of the most important energy resources, have been decreasing and petroleum-originated environmental pollution has been increasing gradually. Hence, studies in the recent years generally focus on renewable energy resources. As an alternative, geothermal energy is recognized as an important source of renewable energy. Accordingly, new technologies are developed in order to use geothermal energy for heating and cooling. Energy pile system is one of these new generation technologies. Solar energy is the basis of earth's interior energy. Earth's surface stores solar energy in summer and when the weather is sunny. Hence, top section of earth is charged with solar energy. Also, geothermal energy can be used at depths over 15 to 20 meters. The principle of this system is to reach to the earth?s energy with piles, extract this energy with heat exchanger pipes and to carry it to the heat pumps over collectors. This system is defined as energy pile. This study first explains the general operational principles of heat pump and classifies according to the energy resources. Then it focuses on energy pile systems, one of the methods used to extract energy from the ground. Working principle and goal of the energy piles are studied and components of a pile as well as the manufacturing stages are illustrated with pictorial aids. Besides the manufacturing stages, implementation principles and test protocol are added. After providing general information about energy piles, the studies on pile heat exchanger types and selection of those are researched. The discussion is focused on determining the most efficient type of heat exchangers on the basis of results got from experimental and numeric studies on heat exchangers. Finally, the calculation method regarding energy extraction from pile circuit on an implementation works completed. The results are discussed by using the levelised cost method. While, the cost-analysis has been performed, the initial investment costs and the operating costs for the heat-pump system and the classic system have been calculated separately. The annual total energy costs have been obtained for both systems by using the leveled cost method as the calculation method. These values respectively for the heat pump and the classic system have been found as 6.505-5.140 ?/year for annual cost of initial investment, as 141.921,8-230.055,9 ?/year for operating costs in respect of current conditions, as 3.025.371,8-4.689.064,9 ? for total annual operating costs in respect of current conditions, as 203.304,9-315.105,1 ?/year for equivalent annual operating costs and as 209.810-320.245,1 ? for total annual costs. The final unit heating energy and payback period have been found based on these above mentioned values. It has been taken into consideration that the classic system is 35% more expensive than the other system in respect of unit heating energy and the payback period has been calculated as 1,1 year.