Using Tunnel Air Heat in the Heat and Cold Supply Systems of Subway Facilities

Abstract

An imbalance of thermal operating conditions in a subway has a negative effect on the microclimate in tunnels and stations and eventually leads to accumulation of “thermal pollution” of the soil strata surrounding the subway tunnels and facilities. In turn, such “thermal pollution” results in less intense heat removal to the soil and in air overheating in stations. One of the efficient methods for achieving better energy efficiency of the climate systems and for improving the microclimate in the Moscow Subway’s underground facilities is to use heat pump systems with recovery of the tunnel air heat for supplying heat and cold for station complexes. The article presents the main results obtained from experimental investigations of the thermal operating conditions at some stations of the Moscow Subway. In particular, air temperature in the subway tunnel spaces was measured in the summer and winter seasons. As a result, the main factors influencing the temperature operating conditions in the subway tunnels have been revealed. Based on the results of the experiments, it can be recommended to put heat pumps into operation in the tunnels for setting up a comfortable microclimate in the subway. As an example, the results from testing this process solution are presented through analyzing the efficiency of the heat pump-based heat supply system of the Salar’evo experimental station’s complex. The analysis of the Salar’evo station’s heat pump-based heat supply system has demonstrated its successful operation in the subway along with good compatibility between the subway systems and heat pump unit at the design and operation stages. Application of heat pump equipment in the heat and cold supply systems of subway facilities is not only significantly cheaper than the conventional technology in terms of one-time capital investments but also makes it possible to save more than 80% of energy in the course of operation.