CN-117029310-B - Heat pump unit

CN117029310BCN 117029310 BCN117029310 BCN 117029310BCN-117029310-B

Abstract

The invention relates to a heat pump unit, which adopts a refrigerant reverse heat pump circulation method to defrost an outdoor heat exchanger, designs a defrosting control method based on the method, determines the maximum opening change coefficient, the minimum opening change coefficient and the ring temperature influence coefficient which influence the opening of an electronic expansion valve through the acquired backwater temperature and the environment temperature, calculates the current opening of the electronic expansion valve by combining the acquired initial temperature, the limiting temperature and the real-time temperature of a coil pipe contact point of an evaporator, ensures that the current opening of the electronic expansion valve is matched with the change requirement of a compressor on the refrigerant flow in the defrosting process, reduces the risk of refrigerant liquid impact of the compressor, improves the defrosting reliability and prolongs the service life of the compressor.

Inventors

WU JINGLONG
TONG FENGXI
ZHENG SHUANGMING

Assignees

中山市爱美泰电器有限公司
热立方科技(佛山市)有限公司

Dates

Publication Date: 20260508
Application Date: 20230808

Claims (7)

1. The utility model provides a heat pump set, includes compressor, cross valve, evaporimeter, electronic expansion valve, the condenser that connects gradually through refrigerant circulation line, and with compressor, cross valve, electronic expansion valve and a plurality of temperature sensor electricity are connected and/or the controller of communication connection, its characterized in that: When the controller receives an instruction for entering defrosting operation but the heat pump unit does not enter defrosting operation, the controller acquires initial state data of the heat pump unit, determines an opening influence factor of the electronic expansion valve according to the initial state data, and calculates the initial opening of the electronic expansion valve according to the opening influence factor and the initial state data, wherein: The initial state data comprises the ambient temperature, the return water temperature of the condenser and the initial temperature of a coil contact point of the evaporator And a set coil contact point limit temperature Operating frequency of the compressor And a set defrosting initial frequency Maximum opening degree of the electronic expansion valve And minimum opening degree ; The aperture influence factor determines the maximum aperture change coefficient according to the backwater temperature and the temperature interval fixed value method And a minimum opening degree variation coefficient Determining the ring temperature influence coefficient according to the ambient temperature and the temperature interval fixed value method ; When the heat pump unit enters defrosting operation, the controller controls the electronic expansion valve to keep the valve not regulated in a first time period under the initial opening degree; After the heat pump unit enters defrosting operation, the controller acquires the temperature of a coil contact point of the evaporator in real time And the coil contact point temperature Defining a temperature at a coil contact point with the initial state data Comparison is performed: If the temperature of the contact point of the coil pipe Less than the coil contact point limit temperature When the electronic expansion valve is in the open state, the controller calculates the current opening of the electronic expansion valve according to the coil contact point temperature, the initial state data and the opening influence factor : ; The current opening is compared with the minimum opening of the electronic expansion valve to output a defrosting opening, the electronic expansion valve is controlled to keep not regulating valve in a defrosting valve regulating period under the defrosting opening, and the temperature of the coil contact point is continuously obtained in real time; If the temperature of the contact point of the coil pipe At least equal to the coil contact point limit temperature And when the controller sends a frequency reducing instruction to the compressor and a valve switching instruction to the four-way valve, the unit working mode control of the compressor and the electronic expansion valve is restored, and the heat pump unit finishes defrosting.
2. The heat pump assembly of claim 1, wherein the initial opening is calculated according to the following equation: in the formula, Indicating the initial opening degree of the electronic expansion valve, Indicating the maximum opening degree of the electronic expansion valve, Represents the maximum opening degree change coefficient determined according to the backwater temperature, Representing the ring temperature influence coefficient determined according to the ambient temperature, Indicating the operating frequency of the compressor, Indicating the set defrosting initial frequency of the compressor.
3. The heat pump unit according to claim 1 or 2, wherein the maximum opening change coefficient is determined in accordance with a temperature interval of the return water temperature by: when the backwater temperature is less than 20 ℃, the maximum opening degree change coefficient =0.5; When the backwater temperature is more than or equal to 20 ℃ and less than 35 ℃, the maximum opening degree change coefficient =0.6; When the backwater temperature is more than or equal to 35 ℃ and less than 45 ℃, the maximum opening degree change coefficient =0.8; When the backwater temperature is more than or equal to 45 ℃ and less than 55 ℃, the maximum opening degree change coefficient =1.0。
4. A heat pump unit according to claim 1 or 2, wherein the ring temperature influence coefficient is determined according to the temperature interval of the ambient temperature by: when the ambient temperature is greater than or equal to 0 ℃ and less than 12 ℃, the ring temperature influence coefficient =1.0; When the ambient temperature is more than or equal to minus 10 ℃ and less than 0 ℃, the ring temperature influence coefficient =0.9; When the ambient temperature is more than or equal to minus 20 ℃ and less than minus 10 ℃, the ring temperature influence coefficient =0.85; When the ambient temperature is less than-20 ℃, the ring temperature influence coefficient =0.8。
5. The heat pump unit according to claim 1, wherein the minimum opening change coefficient is determined in accordance with a temperature interval of the return water temperature by: When the backwater temperature is less than 20 ℃, the minimum opening degree change coefficient =0.5; When the backwater temperature is more than or equal to 20 ℃ and less than 35 ℃, the minimum opening degree change coefficient =0.6; When the backwater temperature is more than or equal to 35 ℃ and less than 45 ℃, the minimum opening degree change coefficient =0.7; When the backwater temperature is more than or equal to 45 ℃ and less than 55 ℃, the minimum opening degree change coefficient =0.9。
6. The heat pump unit according to claim 1, wherein the time period when the controller receives the instruction to enter the defrosting operation but the heat pump unit has not entered the defrosting operation is a time delay preparation period, and the time length of the time delay preparation period is 3-5 minutes.
7. The heat pump assembly of claim 1, wherein the defrost valve adjustment period is less than a valve adjustment period during normal operation of the assembly.

Description

Heat pump unit Technical Field The invention relates to the field of heat pumps, in particular to a heat pump unit. Background The heat pump unit is high-efficiency energy-saving equipment, and when the heat pump unit is operated under the conditions of low outdoor environment temperature and high relative humidity, the outdoor heat exchanger is particularly easy to frost, even the frost is serious to the condition that the heat pump unit cannot be used, so that the heating effect of the heat pump unit is continuously attenuated, and the energy efficiency of the heat pump unit is reduced. For this purpose, defrosting control is required to defrost the frosted outdoor heat exchanger. At present, a heat pump unit mainly adopts a refrigerant reverse heat pump circulation method to defrost an outdoor heat exchanger, namely a four-way valve is arranged on a refrigerant circulation pipeline, and the four-way valve is switched during defrosting, so that high-temperature refrigerant enters the outdoor heat exchanger to release heat to melt frosting on the outer surface of the outdoor heat exchanger. For the unit system, the system can reversely circulate in the defrosting process, and the condensing temperature of the unit is always changed from low to high, so that the circulation quantity of the refrigerant is also changed. However, the current heat pump unit mainly controls the refrigerant flow by using the fixed opening of the electronic expansion valve so as to control the whole defrosting process, and the common control scheme of the opening of the electronic expansion valve during defrosting is as follows: 1) When defrosting is carried out, the electronic expansion valve is subjected to opening adjustment according to the following requirements: A. If the temperature of the backwater is more than 20 ℃, the electronic expansion valve is regulated to a fixed opening degree, the electronic expansion valve is stabilized for 1min, and then the electronic expansion valve is regulated to the current opening degree-100 to continuously run for defrosting set time; B. if the temperature of the backwater is less than or equal to 20 ℃, the electronic expansion valve is regulated to a fixed opening, the electronic expansion valve is stabilized for 1min, and then the electronic expansion valve is regulated to the current opening to 50 for continuous operation until defrosting setting time; C. after defrosting is stopped, the electronic expansion valve is automatically adjusted after being kept for 3min according to the initial opening. 2) When defrosting is carried out, the opening of the electronic expansion valve is fixed at a certain opening. According to the scheme, the electronic expansion valve is fixedly arranged for a relatively long time in the defrosting process, so that the problem of liquid return of the press is easily caused in the defrosting process. Disclosure of Invention Based on the above, the present invention aims to provide a heat pump unit and a defrosting control method thereof, which can control the defrosting process of the heat pump unit under the environment of low temperature and high humidity through the real-time regulation and control of an electronic expansion valve, so that the opening degree of the electronic expansion valve is regulated in real time to match the change of the refrigerant flow requirement of a compressor, and the risk of refrigerant liquid impact of the compressor is reduced. The utility model provides a heat pump set, includes compressor, cross valve, evaporimeter, electronic expansion valve, the condenser that connects gradually through refrigerant circulation line, and with compressor, cross valve, electronic expansion valve and a plurality of temperature sensor electricity are connected and/or the controller of communication connection, its characterized in that: when the controller receives an instruction for entering defrosting operation but the heat pump unit does not enter defrosting operation, the controller acquires initial state data of the heat pump unit, determines an opening influence factor of the electronic expansion valve according to the initial state data, and calculates to obtain the initial opening of the electronic expansion valve according to the opening influence factor and the initial state data; When the heat pump unit enters defrosting operation, the controller controls the electronic expansion valve to keep the valve not regulated in a first time period under the initial opening degree; After the heat pump unit enters defrosting operation, the controller acquires the coil contact point temperature of the evaporator in real time, and compares the coil contact point temperature with the coil contact point limiting temperature in the initial state data: If the coil contact point temperature is smaller than the coil contact point limiting temperature, the controller calculates the current opening of the electronic expansion valve according to the