DETERMINING OF THE OPTIMAL PLACEMENT DEPTH FOR A HORIZONTAL HEAT EXCHANGER OF A HEAT PUMP

Abstract

The article relates to the field of alternative and renewable energy sources. The problem of increasing the efficiency of ground source heat pump equipped with a horizontal heat exchanger is considered. The problem is solved in the framework of the mathematical model of soil as a semi-infinite body with uniform thermal properties. Time and frequency characteristics of the soil as a dynamic object are defined by the heat differential equation. The analysis of the temperature change in the depth of soil due to the annual cycle average daily ambient temperature is considered. Based on this analysis, the conclusion of a zone existing where the heat exchanger will operate with a maximum temperature difference between the soil at the depth of laying and ambient temperature. The mathematical relations that allow to determine the optimum placement depth of the heat exchanger, depending on the thermal diffusivity of the soil, are obtained. The results can be used for the design of heat exchange circuit with soil source heat pumps with horizontal heat exchangers.