Control of Carbon Dioxide Bivalent Heat Pump on Heating of Buildings. Part II

Abstract

The control system of a bivalent heat pump (BHP), using as low potential heat (LPH) sources both the heat of the return water of the network and the heat of the outside air, is considered. The aim of the work is to determine the parameters of the thermodynamic cycle of the heat pump, which would ensure the operation of the heat pump at variable temperatures and flow rates of the refrigerant in the load. The set goal is achieved by solving the following tasks: analy-sis of the methods of synthesis of systems at variable load, analysis of the operation of the sys-tem at random disturbances, development of the heat pump automatic control system (ACS). The main result of the work is: the scheme of the heat pump, which can work with variable pressures of the evaporator and the gas cooler, as well as the technical solution, in which the en-thalpy difference at the evaporator remains constant regardless of the outside air temperatures Significance of the obtained results consists in creation of the BTN scheme, which allows to provide both qualitative and qualitative-quantitative laws of regulation of thermal regime of a building at increase of SOR of a heat pump, thanks to rational choice of a temperature schedule of regulation. Local storage using electrochemical accumulators at the required capacity would be very expensive and would make the entire installation unprofitable. The only reasonable so-lution is interaction with the grid, which requires, in addition to the technical means of interfac-ing, the presence of appropriate regulations governing the transfer of electricity generated by the local facility to the grid, especially if the generation will be carried out throughout the year.

Keywords

• bivalent heat pump scheme
• automatic control
• random disturbances
• reliability
• district heating
• carbon dioxide.