WO2013120375A1

WO2013120375A1 - Method of controlling a heat pump system with two-stage enthalpy increase

Info

Publication number: WO2013120375A1
Application number: PCT/CN2012/086191
Authority: WO
Inventors: 郑晓峰; 魏会军
Original assignee: 国家节能环保制冷设备工程技术研究中心
Priority date: 2012-02-14
Filing date: 2012-12-07
Publication date: 2013-08-22
Also published as: CN103245155A

Abstract

Disclosed is a method of controlling a heat pump system with two-stage enthalpy increase, comprising the following steps: detecting environmental parameters and/or system parameters of the heat pump system with two-stage enthalpy increase; and when the environmental parameters and/or system parameters detected meet preset conditions, controlling the heat pump system with two-stage enthalpy increase so that the enthalpy increase channel is closed. By comparing the system parameters or environmental parameters detected with preset conditions, the method of controlling the heat pump system with two-stage enthalpy increase, feedback regulates the enthalpy increase channel of the system and when preset conditions for the energy efficiency inflection point are met, the heat pump system closes the enthalpy increase channel, making the heat pump system work at a comparatively high energy efficiency ratio, thereby increasing the cooling or heating capacity, and reducing energy consumption.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of compressors, and in particular to a two-stage heat pump system control method. BACKGROUND OF THE INVENTION At present, the heat pump products are better promoted by the national energy efficiency improvement, and the energy-saving performance is better than before. The emergence of frequency conversion technology has a significant improvement over the fixed-speed heat pump, such as rapid cooling, temperature rise, and stable control of the ambient temperature after startup. Technology can avoid frequent shutdowns and starts, and has a good advantage for energy saving and compressor reliability. Although the variable frequency heat pump has made significant progress in energy saving and comfort compared to the fixed speed heat pump, there are still some shortcomings in some extremely extreme weather conditions. For example: high-temperature cooling capacity, ultra-low temperature heating, etc., can not fully meet the needs of consumers. The two-stage enthalpy system can overcome the above shortcomings by supplementing the gas. However, if the system is operated at any time, the performance will decrease under some conditions. SUMMARY OF THE INVENTION The present invention is directed to a method for controlling a two-stage heat pump system that improves energy efficiency. The invention provides a two-stage heat pump system control method, comprising the following steps: detecting environmental parameters and/or system parameters of a two-stage heat pump system; and detecting environmental parameters and/or system parameters satisfying preset conditions At the same time, the two-stage heat pump system is controlled to close the boosting line. Further, the environmental parameters of the two-stage heat pump system include an ambient temperature; when the detected environmental parameters and/or system parameters meet the preset conditions, controlling the two-stage heat pump system to close the boosting pipeline includes: When the ambient temperature of the heat pump system is less than or equal to the preset temperature T1, the two-stage heat pump system is shut down to increase the temperature; when the two-stage heat pump system is in the heating cycle, When the detected ambient temperature is greater than or equal to the heating preset temperature T2, the two-stage heat pump system is controlled to close the boosting pipeline. Further, the range of the cooling preset temperature T1 is 16 ° C ≤ T1 ≤ 30 ° C; the range of the heating preset temperature T2 is 0 ° C ≤ T2 ≤ 20 ° C. Further, the cooling preset temperature T1 = 25 ° C; the heating preset temperature T2 = 10 ° C. Further, the system parameters of the two-stage heat pump system include the operating frequency of the two-stage booster compressor; and when the detected environmental parameters and/or system parameters meet the preset conditions, the control of the two-stage heat pump system is closed. The pipeline includes: When the two-stage heat pump system is running a heating cycle or a refrigeration cycle, when the detected operating frequency is less than or equal to the preset frequency, the two-stage heat pump system is controlled to close the boosting pipeline. Further, the preset frequency F ranges from 10 Hz to F ≤ 50 Hz. Further, the preset frequency F=35HZ. Further, the system parameters of the two-stage heat pump system include exhaust pressure and suction pressure; when the detected environmental parameters and/or system parameters meet the preset conditions, the two-stage heat pump system is controlled to close the boosting pipeline. The method includes: controlling the two-stage heat pump system to close the boosting pipeline when the ratio of the exhaust pressure to the suction pressure is less than or equal to the preset system pressure ratio. Further, the preset system pressure ratio N ranges from 1.5 ≤ N ≤ 3.0. Further, the preset system pressure ratio is N=2.2. Further, the system parameters of the two-stage heat pump system include the evaporation temperature and the condensation temperature of the outdoor unit; when the detected environmental parameters and/or system parameters meet the preset conditions, the two-stage heat pump system is controlled to close the tube. The road includes: When the two-stage heat pump system runs the refrigeration cycle, the detected condensation temperature is less than or equal to 40 ° C, or the detected evaporation temperature is greater than or equal to 10 ° C, and the control two-stage heat pump system is closed. When the two-stage heat pump system is running and heating cycle, when the detected evaporation temperature is greater than or equal to o°c, the two-stage heat pump system is controlled to close the boosting pipeline. According to the control method of the two-stage heat pump system according to the present invention, the feedback adjustment system enhances the pipeline by detecting the system parameter or the environmental parameter and the preset condition, and when the preset preset condition is met, the heat pump system turns off the booster tube. Road, the heat pump system works in a higher energy efficiency ratio, thereby increasing heat production and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a refrigeration cycle of a heat pump air conditioning system of a two-stage heat pump system according to the present invention; FIG. 2 is a heat cycle of a heat pump air conditioning system or a heat pump water heater system of a two-stage heat pump system according to the present invention; schematic diagram; 3 is a schematic view showing a COP (energy efficiency ratio) of a two-stage heat pump system according to the present invention at different frequencies of opening and closing of a booster tube; and FIG. 4 is a double-stage heat pumping system according to the present invention. Turn on and off the COP diagram at different suction pressure and exhaust pressure ratios. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. The method for controlling a two-stage heat pump system according to the present invention comprises the steps of: detecting environmental parameters and/or system parameters of a two-stage heat pump system; and when the detected environmental parameters and/or system parameters satisfy a preset condition, Control the two-stage heat pump system to close the enhanced pipeline. According to the actual operating efficiency characteristics of the two-stage heat pumping system, the invention adjusts the system to increase the pipeline through the actual working system parameters and environmental parameters. The heat pump system is maintained at a higher energy efficiency ratio by controlling the boosting line of the two-stage boosting system to be closed at the energy efficiency inflection point. The environmental parameters of the two-stage heat pump system mainly include the external environment temperature. When the two-stage heat pump system runs the refrigeration cycle, when the detected ambient temperature is less than or equal to the cooling preset temperature T1, the control two-stage heat pump system is turned off. When the two-stage heat pump system is running and heating cycle, when the detected ambient temperature is greater than or equal to the heating preset temperature T2, the two-stage heat pump system is controlled to close the boosting pipeline. According to the actual load, when the heat pump system is in the refrigeration cycle, the preset temperature T1 of the cooling range is 16~30°C. When the ambient temperature is in the range of 16~30°C, according to the actual load of the system, the boosting pipeline is closed. , to ensure that the system operates in the range of higher energy efficiency; when adjusting the system heating cycle, the heating preset temperature T2 ranges from 0 °C to 20 °C, when the ambient temperature is in the range of 0t~20°C, according to the actual system In the case of load, the pipeline is closed and the system is operated in a range with high energy efficiency. The system parameters of the two-stage heat pump system include the operating frequency of the two-stage booster compressor. When the two-stage heat pump system is running a heating cycle or a refrigeration cycle, when the detected operating frequency is less than or equal to the preset frequency F, Control the two-stage heat pump system to close the enhanced pipeline. As shown in Fig. 3, curve S1 represents the energy efficiency ratio of the system opening and increasing at different frequencies, and curve S2 represents the energy efficiency ratio of the system closing and increasing at different frequencies. It can be seen from the figure that S1 and S2 are at the frequency F. The time intersects, that is, the frequency F is the inflection point frequency. It can be seen from the figure that when the operating frequency of the system is lower than the inflection point frequency, the energy efficiency of the system shutdown is higher than that of the opening enhancement. Table 1: Energy-efficiency ratios of the system for increasing and closing the boost at different frequencies Frequency CO

Compressor capacity power remarks

P rated cooling 2590. 1005. 2.57 increase

61

Lane 9 9 6 焓

QXAT-A0 3.17 increase

30 415.3

75 5

Intermediate refrigeration

3.49 Guanzeng

31 369

7 焓 From the data in Table 1, it can be seen that in the intermediate cooling capacity test, the frequency of the open enthalpy is 30 Hz, the energy efficiency ratio (COP) is 3.175, and the calculated SEER (season energy efficiency ratio) is 3.215; The frequency 31Hz COP is 3.497, and the calculated SEER is 3.39. That is to say, at the low frequency, the energy efficiency ratio of the system is higher than that of the open operation. ο' According to the actual load, the preset frequency F of the two-stage heat pump system is 10 50Hz. When the operating frequency range of the heat pump system is 10 50Hz, according to the actual load of the system, the boosting pipeline can be closed. Ensure that the system operates in a range of high energy efficiency. Generally, the cooling environment temperature is higher than 30 ° C, the operating frequency is higher than 50 Hz, or the heating environment temperature is lower than 0 ° C, the operating frequency is higher than 50 Hz, and the system needs to open the increased operation. The system parameters of the two-stage heat pump system include the exhaust pressure and the suction pressure; when the ratio of the exhaust pressure to the suction pressure is less than or equal to the preset system pressure ratio, the two-stage heat pump system is controlled to close the boosting pipeline. . As shown in Fig. 4, the curve S3 represents the energy efficiency ratio of the system opening and increasing in different system pressure ratios (the ratio of the exhaust pressure to the suction pressure), and the curve S4 represents the energy efficiency ratio of the system closing and increasing the ratio at different system pressure ratios. As can be seen from FIG. 4, the curve S3 and the curve S4 intersect when the system pressure ratio is N, that is, the preset system pressure ratio is N. It can be seen from the figure that when the system pressure ratio of the system is lower than the inflection point N, the energy efficiency of the system shutdown is higher than that of the opening enhancement. According to the actual load and environment, the preset system pressure ratio N ranges from 2.0 ≤ N ≤ 3.0. When the ratio of the system's exhaust pressure to the suction pressure is less than or equal to N, the system closes the boost line. When the ratio of exhaust pressure to suction pressure is greater than N, the system boost line is opened. When the system is increased, the pressure in the system flasher is Pm. By monitoring the value of Pm, feedback adjusts the opening of the condenser outlet throttle valve, so that Pm is controlled at 0.8 _{l 0} /Pd P _S (where _Μ is the exhaust pressure, P _S is the suction pressure). According to the actual operating efficiency characteristics of the two-stage enthalpy system, the invention adjusts the system to increase the pipeline through the actual working load conditions. By controlling the opening or closing of the boosting line of the two-stage boosting system, the system is guaranteed to operate at a higher energy efficiency ratio. The invention is described below in connection with specific embodiments of the invention: Embodiment 1: The two-stage heat pump system shown in FIGS. 1 and 2 includes: a two-stage booster compressor 1, and an outdoor heat exchanger 3 interconnected with the compressor 1 through a pipe and a four-way valve 2; Indoor heat exchanger 4. The heat pump system further includes a flasher 5, the flasher 5 is connected to the outdoor heat exchanger 3 and the indoor heat exchanger 4 through a pipe, and the pipe is provided with throttle valves 7a, 7b to control the flow rate of the refrigerant entering the flasher 5, thereby controlling the flash The pressure inside the steamer 5. The flasher 5 is connected to the compressor through a reinforced pipe, and the switch on the reinforced pipe is provided with a solenoid valve 6 to control the reinforced pipe. The heat pump system is provided with a sensor for detecting the operating frequency of the system and a temperature sensor for detecting the ambient temperature, and the opening or closing of the enhanced pipeline section is controlled by the frequency value of the system operation and the ambient temperature value of the outdoor unit. As shown in Fig. 1, under the cooling condition, the preset ambient temperature of the heat pump system is 25 °C. When the ambient temperature is less than or equal to 25 °C, the solenoid valve 6 closes the boosting pipeline; the preset frequency of the heat pump system is preset. 35HZ, when the operating frequency of the system is less than or equal to 35Hz, the solenoid valve 6 closes the boosting pipeline. Only when the ambient temperature is higher than 25 °C and the operating frequency is greater than 35 Hz, the solenoid valve opens the boosting line. As shown in Fig. 2, under the heating condition, the preset ambient temperature of the heat pump system is 10 °C, and when the ambient temperature is greater than or equal to 10 °C, the solenoid valve 6 closes the boosting pipeline. The preset frequency of the heat pump system is preset to 35 Hz. When the operating frequency of the system is less than or equal to 35 Hz, the solenoid valve 6 closes the reinforced pipeline. Only when the ambient temperature is less than 10 ° C and the operating frequency is greater than 35 Hz, the solenoid valve opens the boosting line. Embodiment 2: In the two-stage heat pump system, the opening or closing of the reinforcing pipeline section is controlled by the frequency value of the system operation and the evaporation temperature and the condensation temperature value of the outdoor unit. Under refrigeration conditions, the heat pump system preset condensing temperature is 40 ° C, the evaporation temperature is 10 ° C, when the condensing temperature is lower than 40 ° C, or the evaporation temperature is higher than 10 ° C, the solenoid valve 6 closes the reinforced pipeline. The preset frequency of the heat pump system is 35HZ. When the operating frequency of the system is less than or equal to 35Hz, the solenoid valve 6 closes the boosting pipeline, only when the condensation temperature is higher than 40 °C and the evaporation temperature is lower than 10 °C, and the operation When the frequency is higher than 35Hz, the solenoid valve opens the booster pipeline; under the heating condition, when the evaporation temperature is higher than 0°C, the solenoid valve 6 closes the booster pipeline, and when the running frequency is less than or equal to 35Hz, the solenoid valve is powered off. The system closes the booster pipeline. When the evaporation temperature is lower than 0 °C and the operating frequency is higher than 35 Hz, the solenoid valve is energized and the system boosting pipeline is opened. Table 2: Energy efficiency ratio of the system for opening and closing enthalpy at condensing and evaporating temperatures

It can be seen from Table 2 that under the conditions of condensing temperature of 38 ° C, evaporation temperature of 13 ° C and frequency of 31 Hz, the COP of open enthalpy is 3.189, while the COP of Guan Zeng 达到 is 3.497, which is increased by about 0.31. That is to say, under the above conditions, the efficiency of the system is much higher than that of the operation. Embodiment 3: In the two-stage heat pump system, the preset frequency of the heat pump system is 35HZ. When the operating frequency of the system is less than or equal to 35Hz, the solenoid valve 6 closes the boosting pipeline to make the heat pump system operate in energy efficiency. High non-increased state; When the ratio of the system's exhaust pressure Pd to the suction pressure Ps is less than or equal to 2.2, the solenoid valve 6 closes the boosting line, and the energy efficiency ratio of the system is higher than that when the boosting line is opened. ratio. When the operating frequency is higher than 35 Hz and the ratio of the exhaust pressure Pd to the suction pressure Ps is greater than 2.2, the solenoid valve opens the boosting line. Table 3: Energy efficiency ratio of the system to increase and decrease the growth at low pressure ratio

It can be seen from Table 3 that under the conditions of exhaust pressure of 2.284 MPa, suction temperature of 1.18 MPa, pressure ratio of 1.94, frequency of 31 Hz, the COP of open enthalpy is 3.189, and the COP of Guanzeng 达到 is 3.497. Increase

Around 0.31. That is to say, under the above conditions, the efficiency of the system is much higher than that of the operation. When the system is opened and the pipeline is opened, the pressure in the system flasher is the intermediate pressure Pm. By monitoring the value of Pm, the opening degree of the condenser outlet throttle valves 7a, 7b is feedback-adjusted, so that the Pm is controlled at 0.8~1.0^. ^. If the system closes the booster solenoid valve, the intermediate pressure is not adjusted. From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: According to the control method of the two-stage heat pump system according to the present invention, when the system parameters or environmental parameters meet the preset conditions, the two-stage increase The heat pump system has been increasing and the energy efficiency change will occur. That is, the energy efficiency ratio of the heat pump system is less than the energy efficiency ratio of the non-increased heat. The present invention compares the system parameters or the environmental parameters with the preset conditions, and the feedback adjustment system enhances the pipeline. When the preset preset conditions are met, the heat pump system closes the boosting pipeline, so that the heat pump system operates at a higher energy efficiency ratio, thereby increasing heating or cooling capacity and reducing energy consumption. The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A method for controlling a two-stage heat pump system, characterized in that the method comprises the steps of: detecting environmental parameters and/or system parameters of a two-stage heat pump system;

The dual-stage heat pump system is controlled to close the boosting pipeline when the detected environmental parameter and/or the system parameter meets a preset condition.

2. The method of controlling a two-stage heat pump system according to claim 1, wherein:

The environmental parameters of the two-stage heat pump system include an ambient temperature;

When the detected environmental parameter and/or the system parameter meet the preset condition, controlling the dual-stage heat pump system to close the boosting pipeline includes:

When the two-stage heat pump system runs a refrigeration cycle, when the detected ambient temperature is less than or equal to the cooling preset temperature T1, the two-stage heat pump system is controlled to close the boosting pipeline;

When the two-stage heat pump system is in the heating cycle, when the detected ambient temperature is greater than or equal to the heating preset temperature T2, the two-stage heat pump system is controlled to close the boosting pipeline.

3. The method of controlling a two-stage heat pump system according to claim 2, wherein

The cooling preset temperature T1 ranges from 16 ° C ≤ T1 ≤ 30 ° C;

The heating preset temperature T2 ranges from 0 °C ≤ T2 ≤ 20 °C.

4. The method of controlling a two-stage heat pump system according to claim 3, wherein

The cooling preset temperature T1=25 °C;

The heating preset temperature T2 = 10 °C.

5. The method of controlling a two-stage heat pump system according to claim 1, wherein:

The system parameters of the two-stage heat pump system include the operating frequency of the two-stage booster compressor; and when the detected environmental parameters and/or the system parameters meet the preset conditions, the two-stage heat pump system is controlled. Closing the booster pipeline includes:

When the two-stage heat pump system runs a heating cycle or a refrigeration cycle, when the detected operating frequency is less than or equal to the preset frequency F, the two-stage heat pump system is controlled to close the boosting pipeline.

6. The method of controlling a two-stage heat pump system according to claim 5, wherein

The preset frequency F ranges from 10HZ ≤ F ≤ 50HZ.

7. The method of controlling a two-stage heat pump system according to claim 6, wherein:

The preset frequency F = 35HZ.

8. The method of controlling a two-stage heat pump system according to claim 1, wherein:

The system parameters of the two-stage heat pump system include exhaust pressure and suction pressure; when the detected environmental parameters and/or the system parameters meet preset conditions, controlling the two-stage heat pump system to increase The pipeline includes:

When the ratio of the exhaust pressure to the suction pressure is less than or equal to a preset system pressure ratio, the two-stage heat pump system is controlled to close the boost line.

9. The method of controlling a two-stage heat pump system according to claim 8, wherein:

The preset system pressure ratio N ranges from 1.5 ≤ N ≤ 3.0.

10. The method of controlling a two-stage heat pump system according to claim 9, wherein:

The preset system pressure ratio is N=2.2.

11. The method of controlling a two-stage heat pump system according to claim 1, wherein:

The system parameters of the two-stage heat pump system include an evaporation temperature and a condensation temperature of the outdoor unit; and when the detected environmental parameter and/or the system parameter meet the preset condition, the dual-stage heat pump system is controlled to be closed. Enhancement pipelines include:

When the two-stage heat pump system is operated in a refrigeration cycle, the detected condensation temperature is less than or equal to 40 ° C, or the detected evaporation temperature is greater than or equal to 10 ° C, and the two-stage heat pump is controlled. The system closes the boosting pipeline;

When the two-stage heat pump system is in a heating cycle, when the detected evaporation temperature is greater than or equal to 0 ° C, the two-stage heat pump system is controlled to close the augmentation pipeline.