A frost inhibition system for a winter heat pump outdoor unit

Abstract

The application discloses a frost inhibition system for winter heat pump outdoor unit, and belongs to the technical field of heating, ventilation and air conditioning. The system comprises an air compressor, an evaporative heat exchanger and an air expander which are connected in series to form a high-pressure loop. The air conditioner outdoor unit evaporator, the compressor, the air conditioner indoor unit condenser and the expansion valve of the evaporative heat exchanger are connected in series to form a closed circulation loop. The surface temperature of the evaporative heat exchanger is 2-3 DEG C higher than the frost point temperature through dynamic adjustment of the air compressor. The evaporative heat exchanger replaces the original evaporator of the air conditioner. The application solves the problem of frost formation on the outdoor unit and the reduction of heat exchange efficiency caused by the air conditioner heat pump heating in winter in the prior art. The application can maintain the surface of the air conditioner outdoor unit heat exchanger from frosting, and further improves the efficiency of the heat pump heating.

Description

Technical Field

[0001] This invention belongs to the field of heating, ventilation and air conditioning technology, and in particular relates to a system for suppressing frost formation on outdoor units of heat pumps in winter. Background Technology

[0002] Currently, in the winter heating operation of traditional air source heat pump systems, frost easily accumulates on the surface of the outdoor unit's heat exchanger due to heat and mass exchange with low-temperature, high-humidity air. Existing technologies mainly employ the following defrosting methods: Reverse circulation defrosting: Periodic defrosting is performed by switching the four-way valve, resulting in heating interruption and energy loss. Electric heating defrosting: An additional electric heating device melts the frost layer, increasing additional energy consumption. Hot gas bypass defrosting: Defrosting is performed directly using compressor exhaust, which presents a problem of heat exchanger temperature shock.

[0003] The above methods all belong to passive defrosting technology, which has the following inherent defects: the system stops supplying heat during the defrosting cycle, and the repeated frosting-defrosting process leads to a decrease in heat exchange efficiency. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a winter heat pump outdoor unit frost suppression system. This system can maintain the surface temperature of the air conditioner outdoor unit heat exchanger above the frost point, effectively suppressing the occurrence of frost and improving heat exchange efficiency.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] This invention discloses a winter heat pump outdoor unit frost suppression system, comprising an air compressor, an evaporative heat exchanger, and an air expander connected in series to form a high-pressure circuit; the evaporative heat exchanger consists of an outdoor unit evaporator, a compressor, an indoor unit condenser, and an expansion valve connected in series to form a closed loop; the air compressor adjusts the compression ratio to make the surface temperature of the evaporative heat exchanger 2-3°C higher than the frost point temperature.

[0007] Furthermore, the heat exchange medium of the evaporative heat exchanger is air compressed by an air compressor and refrigerant in the evaporator of the outdoor unit of the air conditioner.

[0008] Furthermore, the air expander and air compressor are connected via a power recovery device to recover power.

[0009] Furthermore, the air compressor adjusts the compression ratio by adjusting the compression ratio through frequency conversion based on the real-time frost point temperature obtained from the ambient temperature and humidity sensor data, so that the surface temperature of the evaporator heat exchanger is 2-3°C higher than the frost point temperature.

[0010] The beneficial effects of this invention are as follows:

[0011] 1. This invention forms a high-pressure circuit by setting up an air compressor, an evaporative heat exchanger and an air expander connected in series. By dynamically adjusting the compression ratio of the air compressor, the surface of the outdoor unit evaporator can be kept above the frost point temperature in winter to prevent frost formation and improve heat exchange efficiency, thus achieving uninterrupted heating.

[0012] 2. In this invention, the air expander and the air compressor are connected by a power recovery device to recover power, converting and recovering the power generated during expansion and transmitting it to the air compressor to provide some energy to the air compressor and reduce energy consumption.

[0013] 3. This invention uses an ambient temperature and humidity sensor to monitor the ambient temperature and humidity in real time, obtain the real-time frost point temperature, and control the air compressor to adjust the compression ratio, so that the drawn-in outdoor air becomes high-temperature and high-pressure air, causing the surface of the evaporator to absorb heat and rise in temperature, which is higher than the air frost temperature, thus inhibiting the formation of frost on its surface. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the outdoor unit frost suppression system of this application.

[0015] Figure 2 This is a schematic diagram of the operation of the evaporator of the outdoor unit of the air conditioner in this application.

[0016] Figure 3 This is a simplified control diagram for this application.

[0017] In the diagram: 1. Compressor, 2. Indoor unit condenser, 3. Expansion valve, 4. Outdoor unit evaporator, 5. Outdoor air, 6. Evaporator exhaust air, 7. Air compressor, 8. Evaporative heat exchanger, 9. Air expander, 10. Exhaust port, 11. Power recovery device, 12. Ambient temperature and humidity sensor, 13. Temperature sensor, 14. Controller. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] Example: Figures 1-3 As shown, the present invention provides a winter heat pump outdoor unit frost suppression system, comprising an air compressor 7, an evaporative heat exchanger 8, and an air expander 9 connected in series to form a high-pressure circuit; the evaporator 4 of the outdoor unit of the evaporative heat exchanger 8, the compressor 1 (the compressor of the refrigerant in the air conditioning system), the condenser 2 of the indoor unit of the air conditioning system, and the expansion valve 3 are connected in sequence to form a closed loop; the compression ratio is adjusted by the air compressor 7 so that the surface temperature of the evaporative heat exchanger 8 is 2-3°C higher than the frost point temperature.

[0020] The evaporative heat exchanger 8 includes an outdoor unit evaporator 4 and an air duct, which are connected to an air compressor 7 and an air expander 9 to form a high-pressure circuit.

[0021] The heat exchange medium of the evaporative heat exchanger 8 is air compressed by the air compressor and refrigerant in the evaporator of the outdoor unit of the air conditioner.

[0022] The air expander 9 and the air compressor 7 are connected via a power recovery device 11 to recover power. The power recovery device 11 is an existing structure, including a mechanical transmission device and an energy conversion device. The mechanical transmission device is used to connect the air expander and the air compressor, and the energy conversion device is used to convert the power output by the air expander into an energy form that can be used by the air compressor.

[0023] The compression ratio adjustment of the air compressor 7 is based on the real-time frost point temperature obtained from the ambient temperature and humidity sensor data (existing technology). The compression ratio is adjusted by frequency conversion of the air compressor 7 to compress the outdoor air to a temperature above the frost point (dew point) temperature, so that the surface temperature of the evaporator heat exchanger 8 is 2-3°C higher than the frost point temperature.

[0024] This embodiment uses the Magnus-Tetens formula (existing) to calculate the real-time frost point temperature:

[0025]

[0026] Where A = 17.62, B ​​= 243.12℃, T is the ambient temperature (℃), and RH is the relative humidity (%).

[0027] like Figure 3 As shown, the present invention also includes a controller 14 and an outdoor ambient temperature and humidity sensor 12 and a temperature sensor 13 connected to the input terminal of the controller 14. The output terminal of the controller 14 is connected to the air compressor 7. The ambient temperature and humidity sensor 12 is used to monitor the outdoor ambient temperature and humidity in real time and transmit the data to the controller 14. The controller 14 obtains the real-time frost point temperature based on the ambient temperature and humidity data. The temperature sensor 13 is set on the surface of the evaporator heat exchanger 8 and is used to monitor the surface temperature of the evaporator heat exchanger 8 in real time. The controller 14 compares the surface temperature of the evaporator heat exchanger 8 with the real-time frost point temperature according to the existing common comparison method in the art. When the surface temperature of the evaporator heat exchanger 8 is lower than the real-time frost point temperature, the controller controls the operation of the air compressor 7 and adjusts the compression ratio by frequency conversion.

[0028] During operation, the present invention uses controller 14 to control the air compressor 7 to adjust the compression ratio via frequency conversion. Specifically, the air compressor 7 draws in outdoor air 5 and compresses it entropyally to generate high-temperature, high-pressure air. The airflow flows into the evaporator heat exchanger 8 and undergoes convective heat exchange with the surface of the evaporator heat exchanger 8, causing the surface of the evaporator heat exchanger 8 to absorb heat and rise in temperature, exceeding the air frosting temperature by 2-3°C, thus inhibiting the formation of frost on its surface. The compressed air after heat exchange enters the air expander 9 for entropy expansion and is discharged into the outdoor air through the exhaust port 10. At the same time, the power recovery device 11 converts and recovers the expanded power and transmits it to the air compressor 7, providing part of the energy to the air compressor 7 and reducing energy consumption.

[0029] Both the air compressor 7 and the air expander 9 are existing frequency converters, capable of flexibly adjusting operating parameters according to the controller's instructions to achieve precise dynamic regulation. The controller 14 is an existing device, and its control and regulation methods are existing technologies, which will not be described in detail here.

[0030] Components not described in detail in this application are all existing conventional technologies and will not be described further here.

[0031] It is understood that the above specific description of the present invention is only for illustrating the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of the present invention.

Claims

1. A system for suppressing frost formation on an outdoor unit of a heat pump in winter, characterized in that: The system includes an air compressor, an evaporative heat exchanger, and an air expander connected in series to form a high-pressure circuit; the evaporative heat exchanger consists of an outdoor unit evaporator, a compressor, an indoor unit condenser, and an expansion valve connected in series to form a closed loop; the air compressor is used to adjust the compression ratio so that the surface temperature of the evaporative heat exchanger is 2-3°C higher than the frost point temperature.

2. The winter heat pump outdoor unit frost suppression system according to claim 1, characterized in that: The heat exchange medium of the evaporative heat exchanger is air compressed by an air compressor and refrigerant in the evaporator of the outdoor unit of the air conditioner.

3. The winter heat pump outdoor unit frost suppression system according to claim 1, characterized in that: The air expander and air compressor are connected via a power recovery device to recover power.

4. The winter frost suppression system for outdoor heat pump units according to claim 1, characterized in that, The air compressor adjusts the compression ratio by adjusting the compression ratio based on the real-time frost point temperature obtained from the ambient temperature and humidity sensor data, so that the surface temperature of the evaporator heat exchanger is 2-3°C higher than the frost point temperature.

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