Air circulation compression type air source heat pump unit

Abstract

The invention discloses an air circulation compression type air source heat pump unit. The air circulation compression type air source heat pump unit mainly comprises a heat regenerator, a compressor,an air cooler, an expansion machine, a driving machine and other components as well as a connecting pipeline, wherein the heat absorption side inlet of the heat regenerator is connected to the ambient atmosphere; the heat absorption side outlet of the heat regenerator is connected to the inlet of the compressor; the outlet of the compressor is connected to the heat release side inlet of the air cooler; the heat release side outlet of the air cooler is connected to the heat release side inlet of the heat regenerator; the heat release side outlet of the heat regenerator is connected to the inlet of the expansion machine; the outlet of the expansion machine is connected to the ambient atmosphere; and the driving machine is used for compensating difference between consumed work of the compressor and consumed work of the expansion machine. As air is adopted as a medium and the expansion machine is utilized to recycle compression work, the air circulation compression type air source heat pump unit solves the problems that in the prior art, the air source heat pump unit is large in heating capacity attenuation and low in energy efficiency when the environment temperature is reduced.

Description

technical field [0001] The invention belongs to the technical field of energy-saving equipment, and in particular relates to a compression heat pump heat supply device which absorbs heat from air and uses air as a circulating medium. Background technique [0002] At present, smog has become one of the most serious and urgent environmental problems in northern my country, posing a serious threat to public health. A large number of studies have shown that smog is closely related to coal-fired heating in winter, and emissions from loose coal combustion account for a considerable proportion. Scattered coal combustion heating is the main heating method in the vast rural areas in the north. It has problems such as convenient use, large total amount, uncontrolled coal quality, and inconvenient supervision. Moreover, most of the scattered coal combustion does not adopt dust removal, desulfurization, and denitrification. And other environmental protection measures, so there are prob...

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Problems solved by technology

However, Freon compression heat pump units and refrigeration units have very different operating conditions. Freon heat pump units that are very suitable for refrigeration have the following problems when heating: first, during cooling operation, Freon heat pumps absorb heat from the room, Therefore, during the whole operation process, the evaporating temperature is basically unchanged, while the Freon heat pump absorbs heat from the outdoor environment during heating operation, and the evaporating temperature will change greatly as the ambient temperature decreases. The temperature is about 0°C (corresponding to the outdoor temperature of 5°C), and the evaporation temperature in the severe cold period is about -25°C (corresponding to the outdoor temperature of -20°C). , the density of the Freon vapor sucked into the compressor decreases rapidly, resulting in a rapid decrease in the circulating mass flow rate, and a rapid decrease in the heat absorbed from the outside, resulting in a large attenuation of heating capacity; secondly, as the evaporation temperature decreases, the compression ratio of the compressor (compression ratio It is equal to the condensing pressure divided by the evaporating pressure. In order to maintain the indoor heating effect, the condensing pressure is basically unchanged or changes slightly, while the evaporating pressure decreases rapidly with the decrease of the ambient temperature, and the evaporating pressure is in fractional molecules, so the change of evaporating pressure is for The compression ratio has a great influence) and increases rapidly. During the heating operation of the whole heating season, the compression ratio required by the system changes from 3 in the early and late cold period to 20 in the severe cold period. Such a wide range of changes makes it difficult for the compressor to operate Maintaining good efficiency under all working conditions affects the heating efficiency; finally, the large compression ratio brings great challenges to the compressor structure. At the same time, with the increase of the compression ratio, the exhaust temperature of the unit rises rapidly, which is close to The insulation damage temperature limit of F-class motors for built-in motors, so the compression ratio cannot be increased infinitely, which also limits the lower limit of the ambient temperature of Freon heat pumps, GB / T25127.2-2010 "Low ambient temperature air source heat pump (cold water ) Unit Part 2: Heat Pump (Chiller) Units for Household Use and Similar Purposes "The lower limit for low-temperature operation is -20°C, which also shows that the current Freon compression heat pump is not suitable for operating in an environment below -20°C

[0006] In addition, in the field of aircraft air conditioning, there is also a technology that uses air compression and expansion for refrigeration. This technology uses high-pressure and high-temperature air from the engine compressor to exchange heat with the external environment to cool down, and then enters the expander for expansion. External output power Finally, the temperature of the air is lowered and then sent to the air-conditioning area. The compressed and expanded air in this technology does not come from the air-conditioning area. It is a one-way process without forming a cycle. At the same time, the recovered expansion work is not supplemented to the compressor. Used to improve the efficiency of compression

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