Method and apparatus for increasing the efficiency of the cogeneration power plant by the heat pump principle utilization for increasing the coolant inlet temperature

Abstract

The method and apparatus for increasing the efficiency of a low-temperature or high temperature heating system, comprising a primary heat releasing unit (i.e. cogeneration unit with fuel cell (FC) or internal combustion engine (ICE)) for co-generation of the heat and power, and at least one secondary heat releasing unit (i.e. heat pump (HP)) for utilization of at least one of the available waste / renewable energy heat sources (HS) from the ambient (A), where the heat generated by said heat pump is preferably used for preheating the heat transfer medium in the return line of the closed loop heating system, wherein a primary heat releasing unit is used to heat the heat transfer medium to the required temperature level of the heat distribution network. The apparatus according to the invention may comprise one or more heat pumps (HP) of the same or different types, and one or more primary heat releasing units in serial, parallel or cascade connection circuits.

Description

TECHNICAL FIELD[0001]The main object of the invention relates to the methods and apparatus for increasing the heating / cooling power of the cogeneration and / or tri-generation power plants by employing the heat pump principle for exploiting the available renewable low temperature heat sources (i.e. from ambient / ground), wherein the heat generated by the heat pump principle utilization is preferably used for preheating, more particularly, for increasing the temperature of the heat transfer medium in the return line of the heat distribution network (i.e. district heating).BACKGROUND ART[0002]Heat pumps that have been used in prior art to enhance the heating power of combined heat and power systems by utilizing the waste heat recovery and renewable heat sources exists in a number of designs. The solution according to the US20100003552 discloses a fuel cell with incorporated heat pump for fuel cell waste heat source (i.e. exhaust gas) utilization, where the key defect of the proposed solu...

AI Technical Summary

Benefits of technology

[0015]According to the invention the heat pump heats the cooling fluid downstream of the heat consumer (i.e. in the return line), wherein at least two advantages can be seen: the temperature at the return line is lower than at the supply line, so that the heat pump has to heat the fluid to lower temperatures (better COP). On the other hand, the control parameter is therefore the temperature of the cooling fluid at the entry of the cooling system for primary heat releasing unit (i.e. cooling system for internal combustion engine, fuel cell). This temperature is easier to control than the classic water temperature at the user (i.e. less fluctuation). It is therefore essential to notice, that at least a portion of the low-temperature heat available from ambient (i.e. ground water <10° C.) is upgraded to the higher-temperature heat (i.e.: 60° C.—max. inlet coolant temperature) by the heat pump principle utilization, wherein generated heat is preferably introduced into the return line of the heat distribution network with aim to increase the inlet temperature of the coolant for cooling system of the primary heat source auxiliaries (i.e. fuel cell cooling system) preferably up to the maximum allowed value, specified by auxiliary component manufacturer, thus substantially higher efficiency of overall power conversion is achieved. Similarly, it is important to notice as well from apparatus perspective point of view, that at least one outlet of the condenser unit of said heat pump is adapted to be associated with the inflow of the cooling system for at least one primary heat releasing unit (i.e. cooling system of the fuel cell, internal combustion engine, etc.).

Problems solved by technology

The solution according to the US20100003552 discloses a fuel cell with incorporated heat pump for fuel cell waste heat source (i.e. exhaust gas) utilization, where the key defect of the proposed solution is that the waste heat generated by the fuel cell is used for heat pump principle utilization, hence the COP of the heat pump is due to high temperatures of the heat transfer medium relatively poor in comparison to herein disclosed solution.

According to the patents DE 10 2012 106894 and DE 39 12 113 the main disadvantage of disclosed solutions is that none of those does not disclose any hint to connect the evaporator and waste heat source recovery unit with closed loop circuit for direct waste heat utilization, as disclosed by herein explained solution.

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