Thermal Losses of a Three-Layer Underground Cylindrical Heat Accumulator of Solar Installations

摘要

Abstract To study the heat losses of a three-layer underground cylindrical heat accumulator (HA), a method for numerically solving the problem of calculating a non-stationary temperature field in the layers of such a system under a symmetrical boundary, has been developed, implemented in the form of a program. Studies of thermal losses of an underground cylindrical HA are carried out. It has been confirmed that no additional thermal insulation is required for the daily underground HA. Creation of a heat-insulating layer in underground HA allows us to increase the period of heat storage up to 10 days with heat loss less than 30%. It is shown that the use of elementary time steps different in time in the calculation makes it possible to reduce the time for calculating heat losses and temperatures in the HA layers by 30 times, up to 1 min, counting per 2000?h of storage. For known temperatures of heat supply and removal in HA according to the pipe-in-pipe scheme, the method and program can be used to study the thermal efficiency of the underground HA, taking into account heat losses in the process of charging and discharging the HA.