HEAT TRANSFER IN THE CHANNELS OF THE HEAT EXCHANGER INTENDED FOR THE RECOVERY VENTILATION SYSTEM OF THE ROOM

Abstract

Air exchange, or ventilation, systems are created to ensure comfortable conditions in rooms in terms of temperature, humidity, and oxygen content in the air. In energy-efficient buildings, the organization of such a system should include energy-saving measures. Among such measures, it should be noted the use of a recuperative heat exchanger, which provides partial heating of the cold outdoor air from the warm air removed from the room in the winter. This paper examines the characteristics of the heat exchanger - recuperator, which is a system of coaxial cylindrical surfaces made of copper. That is, this heat exchanger is a system of annular channels of the "tube-in-tube" type. Technical characteristics are defined for this heat exchanger, which include: thermal power, that is, the amount of heat transferred in the heat exchanger from one heat carrier to another per unit of time; consumption of heat carriers; the temperature of the air removed from the room into the environment after the recuperator; the temperature of the outside air entering the room after the recuperator. The dependence of these characteristics on the number and sizes of annular channels in the heat exchanger and on the pressure drop between the inlet and outlet cross-sections of the channels is investigated. It was determined that the dependence of the degrees of heating and cooling of air flows in the heat exchanger channels on the pressure differences between the inlet and outlet cross sections of the channels are different for heat exchangers with different number of channels and different widths.