APPLICATION OF THE THERMOELECTRIC HEAT PUMPS FOR THE DISTRICT HEATING SYSTEMS

Abstract

The article presents a preliminary analysis of the possibility of applying thermoelectric heat pumps (THP) in low-temperature district heating systems (in the 4–5 generation DH systems). The advantages of THP are the high reliability, the lack of moving parts and freons in their composition, the compactness, the independence of the scale factor. Unlike the compression heat pump, THP provides effective circuit solutions, giving them additional tangible benefits. These features make it possible to reproduce the ideal Lorentz cycle, which can be realized with series-connected thermoelectric modules. The total operating temperature difference is divided into a large number of small intervals, which ensures the high efficiency of each module, and the required temperature difference and performance are achieved by the set of a corresponding number of series-connected micro-THP. It is clear that such a scheme cannot be implemented using compression heat pumps because of a number of technical and economic constraints. There are no such restrictions for thermoelectric heat pumps since each thermoelement is a micro-HPs that can act as a separate THPs. On the example of THP with a rated power of 1kW, the characteristics of the proposed scheme were analyzed. Unlike the classic HP, it has great flexibility. Under given temperature conditions, the power of the considered THP can vary in the range from 0.5 kW to 5 kW only due to a change in the supply current. At the same time, its effectiveness varies in the range from COP = 14 to COP = 2. This opens up new opportunities for the creation of «smart» heating systems that allow optimization of heat consumption modes, adapting them to current needs by purely programmatic methods. The estimated capital cost of THP G » 300 EUR/kW is based on actual data on the current level of component cost. Ref. 6, Fig. 5, Tab. 1.