Hydraulic and thermal stability of independent systems of apartment heating

Introduction. Individual apartment heating has been used in the Russian Federation since 1998. More than two million wall-mounted gas boilers were installed in the apartments of apartment buildings, 99 percent of which are wall-mounted double-circuit convection boilers with atmospheric burners. Their hydraulic and thermal stability is a requirement of the current standards for the design of heating systems. The heat generator of independent heating systems is part of a single circulation circuit; it has its own hydraulic resistance. The circulation of coolant and transfer of thermal energy through the pipelines to heating appliances is performed by the circulation pump. Stability of an independent heating system, in contrast to the centralized one, depends on the regulatory parameters of energy supply (pressure, calorific value of gas, voltage of the electric network). Materials and methods. The authors studied the thermal capacity parameters of the gas burner and the circulation pump within the framework of current standards of variable supply of energy resources and their influence on the hydraulic and thermal stability of systems. Results. Quantitative results of the studied parameters were obtained. The authors identified the coefficient of heat power generation depending on gas pressure, range of pressure change and flow characteristics of circulation pumps, wall boiler hydraulic resistance, influence of thermostatic valves of heating appliances and the use of antifreezes. Conclusion. An independent heating system differs from a centralized one in that a heat generator and a circulation pump are its integral parts. The operating parameters of independent heating systems depend on standard parameters of energy resources supply. Hydraulic resistance does not determine thermal stability. When calculating the hydraulic resistance of the heating circuit, it is necessary to take into account the hydraulic resistance of the gas boiler. Thermal heads on heating appliances and antifreezes in the system of independent apartment heating contradict the concept of hydraulic stability of the heating circuit. Thermal stability of an apartment heating system should be checked taking into account the algorithms of the heat generator performance.