Increasing the heat transfer efficiency of sectional radiators in building heating systems
In heating systems of residential and public buildings, the sectional radiators are widely used as heating devices, where its heat transfer efficiency critically decreases, when the heat-carrying agent’s temperature lowered. At the same time, in order to increase the heat transfer efficiency of heat-exchange equipment, the positive experience of using the pulse flows is known. The heat supply method proposed in the process of the work performing, which consists in periodic supply of hot and cold heat-carrying agent through the sectional radiators. Thermal tests of 12 sectional radiators Rifar BASE 500 type at the temperatures from 42 °C to 67 °C and pulsation frequencies of the heat-carrying agent from 0.52 Hz to 0.62 Hz, showed an increase in their efficiency at the nominal flow rate of 1.8–2.2. With an increase in the flow rate and temperature of the heat-carrying agent, the SR efficiency decreases in a pulsating mode. The study of the SR efficiency from the parameters of the heating system and their switching circuit was carried out on a mathematical model in the form of energy chain that takes into account the mass and storage capacity of the heat-carrying agent. For a parallel connection up to 10 SR, the optimal circular frequency of the heat-carrying agent pulsations was 3 rad/s, and for a serial connection it was 4.2 rad/s, which is consistent with the results of thermal tests at the level of 7 %.