Experimental evaluation of parameters of the system for collection of low-potential heat of the soil body

Abstract

One of the promising ways to solve the problem of improving the energy efficiency of building heating systems is the use of new technologies using non-traditional renewable energy sources. The research target is the geothermal potential of a thermal well in a heat supply system based on heat pumps. The research goal is to assess the possibility of increasing the economic and energy efficiency of the project for the transfer of a heat supply facility to a heat pump heating system using low-grade heat from the surface layers of the Earth. The use of soil as a source of low-grade heat using the technology of heat pumps for heating buildings has been repeatedly studied, however, in practice, when creating geothermal heat pump systems for heat supply, a situation has arisen when at the stage of pre-design study, the average thermophysical characteristics of the soil body and the estimated average air temperature for the heating period are used which leads to an overestimation of the size of the geothermal circuit. To assess the heat potential of the soil at the planned location of the ground heat exchangers, an automated test bench was developed. On the basis of experimental data which make it possible to assess the possibilities of obtaining low-grade renewable heat, the main parameters of the elements of ground heat exchangers are determined. It is proposed to take the bivalent mode of operation of the heat pump as the most justified from the point of view of technical and economic indices of the geothermal heat pump system development and operating costs. And vice versa, the creation of a geothermal heat pump system on the principle of "full replacement" should be carried out only in cases of creating a heat pump heat supply system without the participation of direct electric heating.