| Abstract |
The main application aspects of thermal heat carriers are as follows: production of electricity, heat and cold supply. In the current report we consider two aspects: efficiency of cogeneration of electric and heat energy by the binary low-temperature setups (t = 80ºC) and improvement of efficiency of heat pump systems for multistage heating of delivery water. Results of preproject works on the low-temperature binary power plant of the 200 kW capacity with low-boiling R134a within a thermal power circuit are presented. A water heat carrier with the temperature of 80ºC is used as the heating medium. The main parameters of actuating medium R134a at the main points of the Rankine cycle, gas-dynamic characteristics of axial turbines on R134a, flow-rate and heat-transfer characteristics of power setup and performance characteristics of heat energy transformation are shown. The thermodynamic problem on energy efficiency of multistage water heating in heat supply systems and the problem of determination of performance utility of the considered technology on multistage compression of vapors of the low-boiling actuating medium were solved together at energy analysis of the reverse thermodynamic cycle of multistage compression. Transition to multiple compression always increases the coefficient of energy transformation in a vapor-compression heat pump. However, a growth of energy efficiency depending on the number of compression stages decreases. The technical-economical reasonability of the multistage process acts as a counter factor of energy efficiency. The technical-economical analysis included: determination of additional investments into the system of multistage compression; calculation of operation costs; determination of technical-economical characteristics for every closed heat power circuits and intermediate compression stage, where independent thermodynamic cycles occur; comparative analysis of efficiency for the systems of multistage compression. |