Performance evaluation of a vertical ground-source heat pump system in Izmir, Turkey

Abstract

SUMMARYThis study summarizes the cooling performance of a ground-source heat pump system which was installed in a 65-m 2 room in the Solar Energy Institute, Ege University, Izmir (568 degree-days cooling, base: 228C; 1226 degree-days heating, base: 188C) Turkey. The institute, built in 1986, has a liveable floor area of 3000 m 2 , and uses passive solar techniques. The heating and cooling loads of the room were, respectively, 3.8 and 4.2 kW at design conditions. The system was commissioned in May 2000 and the performance tests have been carried out since then. Based upon the measurements, the heat rejection rate to the soil with an average thermal diffusivity of 0.00375 m 2 h À1 in the cooling mode was found to be in average 51 W m À1 of bore depth, while the maximum entering water temperature to the unit was recorded as 35.98C. The cooling coefficient of performance of the heat pump and the whole system was relatively low when compared to other heat pumps operating under conditions at or near design values. The primary reasons for this were discussed in detail and the potential for performance improvements was also suggested.

Experimental performance investigation of a horizontal ground source compression refrigeration machine

“…Hepbas¸lı [18] has reported that COP r values are in the range of 3.52-4.92 for commercially available systems according to the U.S. Department of Energy (U.S.D.O.E.). In Canada, earth energy systems have COP between 2.5 and 3.8 [42].…”

“…In addition, greater efficiencies can be attained variable speed GSHP instead of single speed one [44]. GSHP is a relatively new technology for Turkey and along with improved system design suggestions as discussed by Hepbaslı [18] and Kavanaugh et al [44], new grouting materials, piping and manifolds with reduced pressure drop, etc., the annual performance factor of GSHP can also be optimized in Turkey. Sanner and Kohlsch [4] have reported that COP of heat pumps for GSHP systems increases linearly with increasing number of tested heat pumps.…”

“…It can be treated as a reasonable assumption for small capacity of the system with small diameter pipe. In the literature, although Kersten's [30] method has been used for the determination of soil thermal conductivity, some other assumptions such as dry density are also required [18]. In this study, moisture and dry Figure 1.…”

“…The overall coefficient of performance (COP) was determined to be 2.8. Hepbaslı [18] experimentally studied a closed-loop GSHP system for cooling mode application in Izmir located in the western region of Turkey that has mediterranean climatic conditions. The cooling COPs of the heat pump (1.09) and whole system (0.85) were relatively low when compared with other heat pumps operating under conditions at or near design values.…”

Development of the Hybrid Operation Method of a Multi-Geothermal Heat Pump System and Absorption Chiller-Heater

“…In the past, many studies have focused on efficiency enhancement and performance evaluations of various GHP systems [2][3][4][5]. Accordingly, studies of GHP are in progress from many worldwide perspectives.…”