阅读说明：本技术 一种热泵系统低水温启动的控制方法 (Control method for low water temperature starting of heat pump system ) 是由 蔡佰明 黄剑峰 于 2020-05-29 设计创作，主要内容包括：本发明提供一种热泵系统低水温启动的控制方法,所述低温级热泵统包括控制器、低温级压缩机、主路电子膨胀阀、增焓辅路电子膨胀阀、室外环境感温传感器、进水感温传感器、出水感温传感器,所述控制器与低温级压缩机、主路电子膨胀阀、增焓辅路电子膨胀阀、室外环境感温传感器、进水感温传感器、出水感温传感器连接,所述进水感温传感器、出水感温传感器分别安装在耗能末端的进水端与出水端,所述低水温启动的控制方法采用一级解除低压步骤与二级解除低压步骤,实现低压压力因为低温级压缩机频率限制在F1而逐渐恢复正常,在达到条件后频率才上升,从而不会再对低压压力造成过低的负面影响。(The invention provides a control method for low water temperature starting of a heat pump system, wherein the low-temperature stage heat pump system comprises a controller, a low-temperature stage compressor, a main circuit electronic expansion valve, an enthalpy-increasing auxiliary circuit electronic expansion valve, an outdoor environment temperature-sensing sensor, a water inlet temperature-sensing sensor and a water outlet temperature-sensing sensor, the controller is connected with the low-temperature stage compressor, the main-path electronic expansion valve, the enthalpy-increasing auxiliary-path electronic expansion valve, the outdoor environment temperature sensor, the water inlet temperature sensor and the water outlet temperature sensor, the water inlet temperature-sensing sensor and the water outlet temperature-sensing sensor are respectively arranged at the water inlet end and the water outlet end of the energy consumption tail end, the control method for starting the low water temperature adopts a first-stage low pressure removing step and a second-stage low pressure removing step to realize that the low pressure gradually returns to normal because the frequency of the low-temperature stage compressor is limited to F1, the frequency rises only after the condition is reached, so that no too low negative influence is caused on the low-pressure.)

1. The control method for low-temperature starting of the heat pump system comprises a controller, a low-temperature stage compressor, a main electronic expansion valve, an enthalpy-increasing auxiliary electronic expansion valve, an outdoor environment temperature-sensing sensor, a water inlet temperature-sensing sensor and a water outlet temperature-sensing sensor, wherein the controller is connected with the low-temperature stage compressor, the main electronic expansion valve, the enthalpy-increasing auxiliary electronic expansion valve, the outdoor environment temperature-sensing sensor, the water inlet temperature-sensing sensor and the water outlet temperature-sensing sensor are respectively arranged at a water inlet end and a water outlet end of an energy consumption tail end, and the control method is characterized in that: the control method for starting the low water temperature comprises the following steps:

(1) a first-stage low pressure relieving step: detecting the current water inlet temperature Ti and the outdoor environment temperature T0, when the water inlet temperature Ti is less than or equal to a first set temperature T1 and the outdoor environment temperature T0 is less than or equal to a second set temperature T2, controlling the opening step number of the main electronic expansion valve to be limited to S1 steps and the opening step number of the enthalpy-increasing auxiliary electronic expansion valve to be limited to S2 steps to close the main electronic expansion valve, starting the low-temperature-stage compressor at the moment, limiting the highest operation frequency of the low-temperature-stage compressor to be F1, and when the water inlet temperature Ti is greater than the first set temperature T1 and the outdoor environment temperature T0 is greater than the second set temperature T2, increasing the frequency of the low-temperature-stage compressor to a target frequency Fm to operate;

(2) a secondary low pressure relieving step: when the low-temperature compressor continuously operates at a target frequency F1, detecting the exhaust temperature Tp of the current low-temperature stage compressor in real time; when the exhaust temperature Tp of the low-temperature stage compressor is not less than the third set temperature T3 and the duration is not less than the first set time T1, controlling the low-temperature stage compressor to be in the frequency increasing mode to the target frequency Fm to operate by the controller; when the discharge temperature Tp of the low-temperature-stage compressor is less than the third set temperature T3 and the duration is less than the first set time T1, the low-temperature-stage compressor operates at the frequency F1, and the duration is not less than the second set time T2, and the controller controls the low-temperature-stage compressor to be in the frequency increasing mode until the target frequency Fm is operated.

2. The control method for the low water temperature start of the heat pump system according to claim 1, characterized in that: in the first low pressure relief step, the first set temperature is 15 ℃ < T1<25 ℃, the second set temperature is: 10 < T2<20 ℃, main circuit electronic expansion valve minimum step limit: s1 ≦ 90 steps, limiting the opening step number of the auxiliary electronic expansion valve: and S2 is 0 step, the controller controls the low-temperature stage compressor to start, and the maximum operation frequency of the low-temperature stage compressor is limited: f1 ≦ 55Hz, target frequency for cryogenic stage compressor: fm ≦ 95 Hz.

3. The control method for the low water temperature start of the heat pump system according to claim 2, characterized in that: t1 is 20 ℃, and the second set temperature is: t2 is 15 ℃, the main circuit electronic expansion valve minimum step number limit S1 is 90 steps, the maximum operating frequency limit of the low temperature stage compressor: f1 is 55Hz, maximum target frequency of the low temperature stage compressor: fm is 95 Hz.

4. The control method for the low water temperature start of the heat pump system according to claim 1, characterized in that: in the secondary low pressure relief step, the first set time is: 15s < t1<25s, second set time: 15m < t2<25 m.

5. The control method for the low water temperature start of the heat pump system according to claim 4, characterized in that: the first set time is: t1 is 20S, and the second set time: t2 is 20 m.

6. The control method for the low water temperature start of the heat pump system according to claim 1, characterized in that: in the secondary de-pressurization step, the third set temperature is: 45 ℃ < T3<55 ℃.

7. The control method for the low water temperature start of the heat pump system according to claim 6, characterized in that: the third set temperature: t3 was 50 ℃.

8. The control method for the low water temperature start of the heat pump system according to claim 1, characterized in that: the control method for starting the low water temperature further comprises a defrosting operation step, after the defrosting operation, a secondary low pressure removing step is carried out, the exhaust temperature Tp of the low-temperature stage compressor is detected, the low-temperature stage compressor normally operates according to the frequency F1 after the exhaust temperature Tp is not less than 50 ℃, the secondary low pressure removing step is carried out after the exhaust temperature Tp is maintained at t2, and the low-temperature stage compressor is increased to the target frequency Fm for operation.

Technical Field

The invention relates to the technical field of heat pump systems, in particular to a control method for low water temperature starting of a heat pump system.

Background

Basic principle of the existing heat pump system: the device mainly comprises a compressor, a condenser, an axial fan, an evaporator, a heat preservation water tank, a water pump, a liquid storage tank, a filter, an electronic expansion valve, an electronic automatic controller and the like. After the power is turned on, the axial flow fan starts to operate, outdoor air is subjected to heat exchange through the evaporator, and the air with the reduced temperature is discharged out of the system by the fan. Meanwhile, the working medium in the evaporator absorbs heat to be vaporized and is sucked into the compressor, the compressor compresses the low-pressure working medium gas into high-temperature and high-pressure gas and sends the high-temperature and high-pressure gas into the condenser, water forced to circulate by the water pump also passes through the condenser, is heated by the working medium and then is sent to a user for use, the working medium is cooled into liquid, the liquid flows into the evaporator again after being throttled and cooled by the electronic expansion valve, and the circulation work is repeated. The heat energy in the air is continuously transmitted into the water, so that the water temperature in the heat-insulating water tank is gradually increased, and the water can reach the use temperature suitable for people.

However, the above-described conventional heat pump system has the following disadvantages in practical control use: when the low-temperature stage compressor is started at low ambient temperature and low water temperature, because the low-pressure is too low, if the low pressure is continuously lower according to the raising speed of the original low-temperature stage compressor, the main machine cannot heat normally, even if the frequency reaches the target frequency and continuously operates, the low-pressure cannot be raised, and finally the main machine is stopped, so that the use is seriously influenced.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a control method for low water temperature starting of a heat pump system, which can judge the required decompression level according to the actual situation and solve the negative influence of the shutdown of a main machine caused by too low pressure.

The invention aims to realize the following steps: the control method for low-water-temperature starting of the heat pump system comprises a controller, a low-temperature-stage compressor, a main-circuit electronic expansion valve, an enthalpy-increasing auxiliary-circuit electronic expansion valve, an outdoor environment temperature-sensing sensor, a water inlet temperature-sensing sensor and a water outlet temperature-sensing sensor, wherein the controller is connected with the low-temperature-stage compressor, the main-circuit electronic expansion valve, the enthalpy-increasing auxiliary-circuit electronic expansion valve, the outdoor environment temperature-sensing sensor, the water inlet temperature-sensing sensor and the water outlet temperature-sensing sensor, and the water inlet temperature-sensing sensor and the water outlet temperature-sensing sensor are respectively installed at a water inlet end and a water outlet end of an energy consumption tail end, wherein the control method:

(1) a first-stage low pressure relieving step: detecting the current water inlet temperature Ti and the outdoor environment temperature T0, when the water inlet temperature Ti is less than or equal to a first set temperature T1 and the outdoor environment temperature T0 is less than or equal to a second set temperature T2, controlling the opening step number of the main electronic expansion valve to be limited to S1 steps and the opening step number of the enthalpy-increasing auxiliary electronic expansion valve to be limited to S2 steps to close the main electronic expansion valve, starting the low-temperature-stage compressor at the moment, limiting the highest operation frequency of the low-temperature-stage compressor to be F1, and when the water inlet temperature Ti is greater than the first set temperature T1 and the outdoor environment temperature T0 is greater than the second set temperature T2, increasing the frequency of the low-temperature-stage compressor to a target frequency Fm to operate;

(2) a secondary low pressure relieving step: when the low-temperature compressor continuously operates at a target frequency F1, detecting the exhaust temperature Tp of the current low-temperature stage compressor in real time; when the exhaust temperature Tp of the low-temperature stage compressor is not less than the third set temperature T3 and the duration is not less than the first set time T1, controlling the low-temperature stage compressor to be in the frequency increasing mode to the target frequency Fm to operate by the controller; when the discharge temperature Tp of the low-temperature-stage compressor is less than the third set temperature T3 and the duration is less than the first set time T1, the low-temperature-stage compressor operates at the frequency F1, and the duration is not less than the second set time T2, and the controller controls the low-temperature-stage compressor to be in the frequency increasing mode until the target frequency Fm is operated.

According to the optimization, in the step of primary low pressure relief, the first set temperature is 15 ℃ and T1 which are less than 25 ℃, and the second set temperature is: 10 < T2<20 ℃, main circuit electronic expansion valve minimum step limit: s1 ≦ 90 steps, limiting the opening step number of the auxiliary electronic expansion valve: and S2 is 0 step, the controller controls the low-temperature stage compressor to start, and the maximum operation frequency of the low-temperature stage compressor is limited: f1 ≦ 55Hz, target frequency for cryogenic stage compressor: fm ≦ 95 Hz.

According to the optimization, the first set temperature T1 is 20 ℃, and the second set temperature: t2 is 15 ℃, the main circuit electronic expansion valve minimum step number limit S1 is 90 steps, the maximum operating frequency limit of the low temperature stage compressor: f1 is 55Hz, maximum target frequency of the low temperature stage compressor: fm is 95 Hz.

According to the optimization, in the step of secondary low pressure relief, the first set time is as follows: 15s < t1<25s, second set time: 15m < t2<25 m.

Optimizing according to the above, the first set time: t1 is 20S, and the second set time: t2 is 20 m.

According to the optimization, in the step of secondary low pressure relief, the third set temperature is: 45 ℃ < T3<55 ℃.

Optimized according to the above, the third set temperature is: t3 was 50 ℃.

According to the optimization, the control method for the low water temperature starting further comprises a defrosting operation step, after the defrosting operation, a secondary low pressure removing step is carried out, the exhaust temperature Tp of the low-temperature stage compressor is detected, the low-temperature stage compressor normally operates according to the frequency F1 after the exhaust temperature Tp is not less than 50 ℃, the secondary low pressure removing step is carried out after the exhaust temperature Tp is maintained at t2, and the low-temperature stage compressor is subjected to frequency rising to the target frequency Fm to operate.

The invention has the advantages that: by adopting the control method, the low-pressure is gradually restored to be normal because the frequency of the low-temperature stage compressor is limited to F1, and the frequency is increased after the condition is reached, so that the low-pressure is not influenced excessively.

Drawings

Fig. 1 is a schematic diagram of the operation of the preferred embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the low-temperature stage compressor and the discharge temperature according to the preferred embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the opening of the main electronic expansion valve and the time variation according to the preferred embodiment of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1 to 3, the control method for low water temperature start of a heat pump system according to the present invention includes a controller, a low temperature stage compressor, a main circuit electronic expansion valve, an enthalpy-increasing auxiliary circuit electronic expansion valve, an outdoor environment temperature sensor, a water inlet temperature sensor, and a water outlet temperature sensor, wherein the controller is connected to the low temperature stage compressor, the main circuit electronic expansion valve, the enthalpy-increasing auxiliary circuit electronic expansion valve, the outdoor environment temperature sensor, the water inlet temperature sensor, and the water outlet temperature sensor, and the water inlet temperature sensor and the water outlet temperature sensor are respectively installed at a water inlet end and a water outlet end of an energy consumption terminal, wherein the control method for low water temperature start includes the following steps:

(1) a first-stage low pressure relieving step: and detecting the current water inlet temperature Ti and the outdoor environment temperature T0, and when the water inlet temperature Ti is less than or equal to a first set temperature T1 and the outdoor environment temperature T0 is less than or equal to a second set temperature T2, controlling the opening step number of the main electronic expansion valve to be limited to S1 steps and controlling the opening step number of the enthalpy-increasing auxiliary electronic expansion valve to be limited to S2 steps to close. The low-temperature-stage compressor at this time is started and the maximum operation frequency of the low-temperature-stage compressor is limited to F1, and the low-temperature-stage compressor is up-converted to the target frequency Fm operation when the intake water temperature Ti > the first set temperature T1 and the outdoor ambient temperature T0> the second set temperature T2.

(2) A secondary low pressure relieving step: when the low-temperature stage compressor is continuously operated at the target frequency F1, the discharge temperature Tp of the current low-temperature stage compressor is detected in real time. When the discharge temperature Tp of the low-temperature-stage compressor is larger than or equal to the third set temperature T3 and the duration is larger than or equal to the first set time T1, the controller controls the low-temperature-stage compressor to be in the up-conversion mode to the target frequency Fm. When the discharge temperature Tp of the low-temperature-stage compressor is less than the third set temperature T3 and the duration is less than the first set time T1, the low-temperature-stage compressor operates at the frequency F1, and the duration is not less than the second set time T2, and the controller controls the low-temperature-stage compressor to be in the frequency increasing mode until the target frequency Fm is operated.

Wherein, in the step of first-stage low pressure relief, the first set temperature is 15 ℃ and T1 and 25 ℃, and the second set temperature is: 10 < T2<20 ℃, main circuit electronic expansion valve minimum step limit: s1 ≦ 90 steps, limiting the opening step number of the auxiliary electronic expansion valve: and S2 is 0 step, the controller controls the low-temperature stage compressor to start, and the maximum operation frequency of the low-temperature stage compressor is limited: f1 ≦ 55Hz, target frequency for cryogenic stage compressor: fm ≦ 95 Hz. In the secondary low pressure relief step, the first set time is: 15s < t1<25s, second set time: 15m < t2<25 m. The third set temperature: 45 ℃ < T3<55 ℃.

In the practical optimization scheme, the first set temperature T1 is 20 ℃, and the second set temperature: t2 is 15 ℃, the main circuit electronic expansion valve minimum step number limit S1 is 90 steps, the maximum operating frequency limit of the low temperature stage compressor: f1 is 55Hz, maximum target frequency of the low temperature stage compressor: fm is 95 Hz. The first set time is: t1 is 20S, and the second set time: t2 is 20 m. The third set temperature: t3 was 50 ℃.

That is, when the heat pump is started at a low ambient temperature and a low water temperature, the current inlet water temperature Ti and the outdoor ambient temperature T0 are detected in real time. And when the water inlet temperature Ti is less than or equal to 20 ℃ and the outdoor environment temperature T0 is less than or equal to 15 ℃, entering a first-stage low pressure removing step. The controller controls the opening step number of the main electronic expansion valve to be limited to 90 steps, and the opening step number of the enthalpy-increasing auxiliary electronic expansion valve to be limited to 0 step to close. At this time, the low temperature stage compressor is started and the low temperature stage compressor is continuously operated with the maximum operation frequency limited to 55 Hz. If the inlet water temperature Ti is more than 20 ℃ and the outdoor environment temperature T0 is more than 15 ℃, the low-temperature stage compressor is increased to the maximum target frequency of 95Hz for operation.

During continuous operation, the current discharge temperature Tp of the low-temperature stage compressor is detected in real time. And when the exhaust temperature Tp of the low-temperature stage compressor rises by more than or equal to 50 ℃ and the duration is more than or equal to 20S, the first-stage decompression step is exited, the second-stage decompression step is entered, and the controller controls the low-temperature stage compressor to operate when the low-temperature stage compressor rises to the target frequency of 95 Hz. When the exhaust temperature Tp of the low-temperature stage compressor is less than 50 ℃ and the duration is less than 20S, the low-temperature stage compressor operates at the frequency of F1, when the duration is greater than or equal to 20m, the first-stage decompression step is also exited, the second-stage decompression step is entered, and the controller controls the low-temperature stage compressor to be operated at the target frequency of 95 Hz.

Thus, by adopting the control method, the low-pressure is gradually restored to be normal because the frequency of the low-temperature stage compressor is limited to 55Hz, and the frequency is increased after the condition is reached, so that the low-pressure is not influenced excessively.

The above embodiments are only embodiments with better effects, and all the structures that are the same as or equivalent to the control method for the low water temperature start of the heat pump system of the present invention are within the protection scope of the present invention.