Experimental Analysis for the Performance of a Geothermal Heat Exchanger Made of Environmentally Friendly Materials

Geothermal heat exchanger (GHE) technology is commonly used in residential and small non-residential buildings, and examples of innovative compact GHE designs are provided. The essential physical properties and processes involved in shallow GHE behavior are described, some of which may be more complex than those required for other types of GHE. This paper discusses the use of a geothermal heat exchanger to extract underground energy for heating and cooling systems and focuses specifically on designing a ground heat exchanger made of environmentally friendly materials suitable for working in the zone of Babylon Governorate in Iraq. At different burial depths, three systems of horizontal heat exchangers were designed. The heat exchanger was designed with pipes made of peroxide cross-linked polyethylene (PEX), in which the pipes were buried to a depth of 2 m under the soil. Also, another system was designed where the pipes are made of multi-layer composite pipe (Mlcp) at a burial depth of 2.5 m and another layer at a depth of 3 m. In this research, several tests were carried out to reach the conditions in which the ground heat exchanger is at its best performance. The effect of buried depth on heat removed from the space has been studied. This test was studying at a flow rate equal to (4 lpm) and the inlet temperature of water equal to approximately (50℃). The effect of changing the flow rates on heat removed from the ground heat transfer system is being studied. Buried depth of PEX pipes is 2m, inlet water temperature (50℃) is chosen as a case study to analyze this effect. The first experimental has shown the heat removed is equal to 2200.942 watts at 8.30 am when buried at a depth of 2m, while it reaches 3679.474 watts at a depth of 3 m. The results show the maximum coefficient of performance (COP) at (3 lpm) is 12.897 and it becomes 5.99 at 4 LPM. Also, the results show that the COP of PEX pipes can be higher than that of its counterparts when pipes are made from MLCp.