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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

THERMAL PERFORMANCE OF GROUND SOURCE HEAT PUMPS THAT USE DIRECT EXPANSION METHOD USING FOUNDATION PILE

Get access (open in a dialog) DOI: 10.1615/IHTC16.nee.023590
pages 7874-7881

Resumo

Ground source heat pumps (GSHPs) use buried pipes to extract heat from the ground and to release heat to the ground. This heat can be used for air conditioning, underfloor and warm-air heating systems, and hot water heaters in dwellings. In ground source heat pumps, two types of systems are applied, namely, an indirect method and a direct expansion method. In the direct expansion method, a refrigerant transfers thermal energy through a primary loop without mediation. Therefore, it is expected that thermal energy is transferred effectively, and performance is promoted. In the present study, the ground source heat pump that uses direct expansion method using the underground heat exchanger which used the narrow copper tubes directly inserted into a foundation pile filled with water. We have carried out an experiment using the 15 sets of steel foundation piles, and have carried out the experiment under the condition of 27 °C and 20 °C as room temperature for cooling and for heating. The amount of heat transferred was evaluated by measuring an enthalpy difference at the indoor unit. The prospect that coefficient of performance (COP) of this method was higher than that of the indirect method of ground source heat pump was obtained. The value of COP were obtained for the direct-expansion-type ground source heat pump operating in both the cooling and heating modes. The experimental results showed that the average COP was around 7 and 6 in the cooling and in the heating operation, respectively.