Subsection heat-taking type overlapping heat pump

Abstract

The invention provides an overlapping-typed heat pump for extracting heat sectionally, which belongs to the technical field of surplus heat utilization and heat pump/ refrigeration. According to the disadvantages that an overlapping-typed unit for extracting heat in a single segment way has low performance index under the circumstances that the temperature range needed by a heat consumer is wide, the final temperature is high, etc., the invention provides an overlapping-typed unit for extracting heat sectionally. Either the invention comprises an evaporator, a compressor, a compound condenser-evaporator and a throttling valve, and adopts the low-temperature stage heat pump flow of a first working substance to satisfy the high-temperature stage heating need and the low-temperature section heating for the heat consumer at the same time, and then comprises the compressor, a condenser, the compound condenser-evaporator and the throttling valve, and adopts the high-temperature stage heat pump flow of a second working substance to satisfy the high-temperature section heating for the heat consumer, or the convention forms a new heat pump flow by the condenser as well as the throttling valve which are added, and the relative components of the overlapping-typed unit; a surplus heat medium flows through the evaporator to release heat, and heating mediums extract heat from different temperature stages. The invention decreases heat transfer temperature difference, increases the performance index; the invention is more particularly suitable for the occasions of high heat supply temperature and wide range; and the invention can decrease the power consumption when being used in refrigeration.

Description

technical field [0001] The utility model belongs to the field of waste heat utilization and heat pump / refrigeration technology. Background technique [0002] The cascade heat pump is formed by cascading two or more separate heat pump systems, each of which has different temperature levels and uses different working fluids. In the traditional cascade unit, the low-temperature stage is responsible for obtaining waste heat and supplying heat to the high-temperature stage, while the high-temperature stage is responsible for providing heat to the heated medium, which is a single-stage heat extraction unit. [0003] When the heated medium needs to be heated from a lower temperature to a higher temperature, the single-stage heating type cascade unit must have such a defect: all temperature sections of the heated medium are heated by the highest temperature grade working fluid. Cooling and condensing heat release are sufficient, that is, the heat extraction of the low-temperature s...

AI Technical Summary

Problems solved by technology

[0003] When the heated medium needs to be heated from a lower temperature to a higher temperature, the single-stage heating type cascade unit must have such a defect: all temperature sections of the heated medium are heated by the highest temperature grade working fluid. Cooling, condensing heat release to meet, that is to say, the heat extraction of the low-temperature section of the heated medium must also be completed by the highest heat supply of the unit, which will inevitably make the heat transfer temperature difference of the unit large, resulting in a decrease in the performance index of the unit

Due to the limitation of the ambient temperature, the initial temperature of the cooling medium entering the unit cannot be lowered arbitrarily. In order to prevent the performance index of the unit from being too low, the current solution to this defect is to reduce the temperature change of the cooling medium entering and leaving the unit. The measures brought about the problems of large flow of cooling medium and high energy consumption of auxiliary systems

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