TEST OF A PILOT INSTALLATION OF A SOIL REGENERATOR FOR GREENHOUSES

The relevance of the development of ground regenerative heat exchangers is determined by the need to save energy resources for heating greenhouses at night and maintaining the required temperature level during the day. The aim of the work is to study working capacity of a ground regenerator for a greenhouse when testing a pilot plant in full-scale conditions. To achieve this goal the following main tasks were solved: experimental research of soil regenerator pilot plant operation was carried out, the heating period of nozzle and cooling period were determined by the obtained temperature curves, the coefficient of intercomponent heat exchange during the heating period was estimated, the rationality of material choice for granulated nozzle was proved, recommendations on improvement of soil regenerator design for industrial use were developed. The research was conducted on a pilot installation of a soil regenerator, which consists of a heat-exchange duct filled with granulated material and covered with a layer of insulation, and ducts with an exhaust duct fan installed at the outlet. Data on air and nozzle temperatures, which were taken during the day, were used to conduct thermal calculations and assess the efficiency of the ground regenerator. It was determined that the heating period at the selected loading mass of 15.5 kg is not long relative to the duration of the experiment and was 166 min. To increase the amount of accumulated heat it is recommended to increase the weight of the nozzle and air flow rate. It was determined that the coefficient of inter-component heat transfer during the heating period varied between 4 W/m2K and 9 W/m2K. In this case, the Bio number is in the range of 0.05 - 0.10, which allows us to conclude that the use of crushed stone as a nozzle material is rational. It is recommended to increase the thickness of insulation to 4.3 cm so that the heat loss from the heat exchange section does not exceed 5%, and to provide the installation of insulated plugs at the ends of the heat exchange section, closing after the end of the heating period.