Operation method for inhibiting frosting of heat pump

Abstract

The operation method for inhibiting frosting of the heat pump comprises the heat pump and comprises the following steps during operation: step 1, electrifying the heat pump to operate, and entering step 2; 2, heating operation is carried out, and the step 3 is carried out; and thirdly, the central controller of the heat pump judges whether K1 is larger than or equal to Ks or not, if yes, the fourth step is executed, and if not, the second step is executed, K1 is the actual operation time when the current compressor operates stably at the operation frequency, Ks is the set operation time, and the value range of Ks is 2-5 min. On the basis of normal heating of the heat pump and normal control of the electronic expansion valve, whether B1 is greater than B2, whether Ts is greater than or equal to Ta and whether C1 is greater than or equal to C2 are judged through the central controller, and whether the current heating capacity meets the requirements of customers is judged in time, so that the heating process is controlled; therefore, the heat pump always operates efficiently under the condition that the heat pump is not frosted or the frosting of the heat pump is slowed down, and the energy efficiency ratio of the product is improved.

Description

Technical Field

[0001] The invention relates to a heat pump, and in particular to an operating method for inhibiting frost formation in a heat pump. Background Art

[0002] During the heating operation of the heat pump, its refrigerant exchanges heat with the outdoor air through the outdoor heat exchanger. The outdoor heat exchanger absorbs heat from the outdoor air, resulting in a lower temperature of the surrounding air. The water vapor in the air will condense into frost and adhere to the surface of the outdoor heat exchanger, affecting the heat exchange capacity of the outdoor heat exchanger and reducing the heating capacity of the heat pump. Therefore, when the frost reaches a certain degree, the heat pump will enter defrosting, and defrosting will also cause the heating capacity of the heat pump to decrease.

[0003] In response to this situation, some manufacturers have made some improvements. For example, Chinese patent CN 110360775A disclosed a method for inhibiting frosting of a heat pump on October 22, 2019, including the following contents: judging the frosting state of the heat pump unit and when judging that the heat pump unit is in the frost crystal growth period, opening the control valve connected in parallel with the throttling device of the heat pump unit. When judging that the heat pump unit is in the frost layer growth period, closing the control valve. When the detected water tank temperature Twater is less than the preset temperature value S3 and the detected outdoor ambient temperature Tring is greater than the preset temperature value H3, then judging the frosting state on the heat pump unit to control the opening and closing state of the control valve. When the difference between the detected coil temperature Ttube and the detected outdoor ambient temperature Tring is less than or equal to the sum of the preset temperature value C and the value a, where a>0, the closed control valve is opened. When the difference between the detected coil temperature Ttube and the detected outdoor ambient temperature Tring is less than the preset temperature value C, the opened control valve is closed. The checked outdoor environment temperature T ring value is within the interval greater than the preset temperature value H3 and less than the preset temperature value H2. When the detected water tank temperature T water is less than the preset temperature value S3 and greater than the preset temperature value S2, the preset temperature value C is C1. The checked outdoor environment temperature T ring value is within the interval greater than the preset temperature value H3 and less than the preset temperature value H2. When the detected water tank temperature T water is less than the preset temperature value S2 and greater than the preset temperature value S1, the preset temperature value C is C2; wherein C1≠C2. The actual use effect of this method of inhibiting frost on the heat pump is not ideal and needs to be improved. Summary of the invention

[0004] The object of the present invention is to provide an operating method for suppressing frost formation in a heat pump with a high energy efficiency ratio, so as to overcome the shortcomings of the prior art.

[0005] An operating method for suppressing frost formation in a heat pump designed for this purpose includes a heat pump, and is characterized in that the operation includes the following steps:

[0006] Step 1: the heat pump is powered on and starts running, and then proceeds to step 2;

[0007] Step 2: heating operation, proceed to step 3;

[0008] Step 3, the central controller of the heat pump determines whether K1≥Ks is established. If it is established, it goes to step 4, otherwise it goes to step 2, wherein K1 is the actual operating time when the operating frequency of the current compressor is running stably, Ks is the set operating time, and the value range of Ks is 2 to 5 minutes;

[0009] Step 4: The central controller determines whether B1>B2 is established. If it is established, it goes to step 5, otherwise it goes to step 8, where B1 is the actual evaporation temperature drop rate within Tm time, B2 is the set evaporation temperature drop rate within Tm time, Tm is the time constant, and the value range of Tm is 0 to 10min;

[0010] Step 5: The central controller determines whether Ts≥Ta is established. If it is established, it goes to step 6, otherwise it goes to step 9, where Ts is the current actual exhaust superheat value, Ta is the set target exhaust superheat, and the value range of Ta is 0-100°C;

[0011] Step 6, adjust the target return air superheat, Tb(n+1)=Tb(n)-ΔT, and proceed to step 7;

[0012] Among them, the value range of n is 0 and natural numbers;

[0013] When n=0, Tb(0) is the preset target return air superheat, the value range of Tb(0) is 0-10°C, Tb(1) is the current target return air superheat after the first adjustment, and Tb(1)=Tb(0)-ΔT;

[0014] When n=1, Tb(2) is the current target return air superheat after the second adjustment, and Tb(2)=Tb(1)-ΔT, and so on;

[0015] ΔT is the correction value of the preset target return air superheat, the value range of ΔT is 0~5℃, Tb(0)>ΔT;

[0016] Step 7, continue running and enter step 4;

[0017] Step 8: Normal valve control, go to step 2;

[0018] Step 9, the central controller determines whether C1≥C2 is established. If it is established, it enters step 10, otherwise it enters step 8, where C1 is the actual change value of the water temperature within the Tm time, C2 is the set change value of the water temperature within the Tm time, and the value range of C2 is 0-5°C;

[0019] Step 10: The operating frequency of the current compressor is reduced by one gear every 5 minutes, and the process goes to step 7.

[0020] After the present invention adopts the above-mentioned technical scheme, on the basis of the normal heating of the heat pump and the normal control of the electronic expansion valve, the central controller judges whether B1>B2, whether Ts≥Ta and whether C1≥C2 are established, and timely judges whether the current heating amount meets the customer demand, thereby controlling the heating process, so that the heat pump can always run efficiently without frosting or the heat pump can slow down frosting, thereby improving the energy efficiency ratio of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. 4 is an operation flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] See also Figure 1 , an operating method for inhibiting frost formation in a heat pump, comprising a heat pump, and when operating, comprising the following steps:

[0024] Step 1: The heat pump is powered on and starts running, and then proceeds to step 2.

[0025] Step 2: Heating operation, go to step 3.

[0026] Step 3, the central controller of the heat pump determines whether K1≥Ks is established. When it is established, it enters step 4, otherwise it enters step 2, wherein K1 is the actual operating time when the operating frequency of the current compressor is running stably, Ks is the set operating time, and the value range of Ks is 2 to 5 minutes.

[0027] In this embodiment, the heat pump uses an ordinary normal valve control program to control components such as the compressor and the electronic expansion valve according to the ambient temperature and the user's heating needs. When the heating amount of the heat pump reaches the user's needs, the operating frequency of the compressor will gradually become stable. This process is called the normal valve control program, or normal valve control for short.

[0028] When K1≥Ks is established, that is, when the actual operating time K1 of the current compressor when the operating frequency is stably running is greater than the set operating time Ks, the technical solution provided by the present invention is entered for control, so that the heat pump can always operate efficiently without frosting or the heat pump can slow down frosting, so as to improve the energy efficiency ratio of this product.

[0029] In step 4, the central controller determines whether B1>B2 is established. If it is established, it enters step 5, otherwise it enters step 8, where B1 is the actual evaporation temperature drop rate within the Tm time, B2 is the set evaporation temperature drop rate within the Tm time, Tm is the time constant, and the value range of Tm is 0 to 10 minutes.

[0030] In this embodiment, when B1>B2 is established, it can be determined that the current heat pump has a tendency to frost too quickly. Therefore, when the exhaust gas meets the conditions, the target return air superheat should be adjusted.

[0031] In this embodiment, when B1≤B2 holds, the technical solution of the present invention is exited and the normal valve control logic of the heat pump is entered, that is, the control of the compressor, electronic expansion valve and other components during normal heating of the ordinary heat pump is exited and is no longer restricted by the technical solution of the present invention.

[0032] In step 5, the central controller determines whether Ts≥Ta is established. If it is established, it enters step 6, otherwise it enters step 9, where Ts is the current actual exhaust superheat value, Ta is the set target exhaust superheat, and the value range of Ta is 0 to 100°C.

[0033] Step six, adjust the target return air superheat, Tb(n+1)=Tb(n)-ΔT, and proceed to step seven.

[0034] In this embodiment, by adjusting the target return air superheat to a smaller value, the opening of the heat pump main circuit electronic expansion valve is increased, and the refrigerant mass of the heat pump system is increased to increase the evaporation temperature.

[0035] The value range of n is 0 and a natural number.

[0036] When n=0, Tb(0) is the preset target return air superheat, the value range of Tb(0) is 0-10°C, and Tb(1) is the current target return air superheat after the first adjustment.

[0037] Tb(1)=Tb(0)-ΔT.

[0038] Before the first adjustment, the current target return air superheat is Tb(0), and after the first adjustment, the current target return air superheat is Tb(1).

[0039] When n=1, Tb(2) is the current target return air superheat after the second adjustment, and Tb(2)=Tb(1)-ΔT, and so on.

[0040] ΔT is the correction value of the preset target return air superheat, the value range of ΔT is 0~5℃, Tb(0)>ΔT.

[0041] After the second adjustment, the current target return air superheat is Tb(2).

[0042] Example: The preset target return air superheat Tb(0)=10°C, the preset target return air superheat correction value ΔT=0.5°C, when the central controller determines that K1≥Ks is established, at this time, K1≥Ks is established for the first time, and the compressor enters a stable operation state.

[0043] When B1>B2 and Ts≥Ta is established, Tb(1)=Tb(0)-ΔT=10℃-0.5℃=9.5℃. Therefore, the operation continues on the basis of the current target return air superheat being changed to Tb(1)=9.5℃, so that the heat pump can always operate efficiently without frosting or the heat pump can slow down frosting, so as to improve the energy efficiency ratio of this product.

[0044] If the calculated current target return air superheat is less than or equal to zero, the value of the current target return air superheat is set to zero and the process goes to step seven.

[0045] In this embodiment, when B1-B2≤0, the value of ΔT is 0; when 0>B1-B2≥0.2, the value of ΔT is 0.5; when 0.2>B1-B2≥0.4, the value of ΔT is 1; when B1-B2>0.4, the value of ΔT is 1.5.

[0046] Step 7: Continue running and go to step 4.

[0047] Step 8: Normal valve control, go to step 2.

[0048] Step nine, the central controller determines whether C1≥C2 is established. If it is established, it goes to step ten, otherwise it goes to step eight, where C1 is the actual change value of the water temperature within the Tm time, C2 is the set change value of the water temperature within the Tm time, and the value range of C2 is 0~5℃.

[0049] In this embodiment, when B1>B2 and Ts<Ta, it is necessary to determine whether C1≥C2 is established. When C1≥C2 is established, it is determined that the current heating amount meets the customer demand, and the process goes to step ten.

[0050] When B1>B2 and Ts<Ta, and C1<C2 holds true, it is determined that the current heating amount cannot meet customer demand, and the process goes to step eight, entering the normal valve control logic of the heat pump, and is no longer constrained by the technical solution of the present invention.

[0051] Step 10: The current operating frequency of the compressor is reduced by one gear every 5 minutes, and the process goes to step 7.

[0052] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0053] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An operating method for inhibiting frost formation in a heat pump, comprising a heat pump, characterized in that The operation includes the following steps: Step 1: the heat pump is powered on and starts running, and then proceeds to step 2; Step 2: heating operation, proceed to step 3; Step 3, the central controller of the heat pump determines whether K1≥Ks is established. If it is established, it goes to step 4, otherwise it goes to step 2, wherein K1 is the actual operating time when the operating frequency of the current compressor is running stably, Ks is the set operating time, and the value range of Ks is 2 to 5 minutes; Step 4: The central controller determines whether B1>B2 is established. If it is established, it goes to step 5, otherwise it goes to step 8, where B1 is the actual evaporation temperature drop rate within Tm time, B2 is the set evaporation temperature drop rate within Tm time, Tm is the time constant, and the value range of Tm is 0 to 10min; Step 5: The central controller determines whether Ts≥Ta is established. If it is established, it goes to step 6, otherwise it goes to step 9, where Ts is the current actual exhaust superheat value, Ta is the set target exhaust superheat, and the value range of Ta is 0-100°C; Step 6, adjust the target return air superheat, Tb(n+1)=Tb(n)-ΔT, and proceed to step 7; Among them, the value range of n is 0 and natural numbers; When n=0, Tb(0) is the preset target return air superheat, the value range of Tb(0) is 0~10℃, and Tb(1) is the current target return air superheat after the first adjustment. Tb(1)=Tb(0)-ΔT; When n=1, Tb(2) is the current target return air superheat after the second adjustment, and Tb(2)=Tb(1)-ΔT, and so on; ΔT is the correction value of the preset target return air superheat, the value range of ΔT is 0~5℃, Tb(0)>ΔT; Step 7, continue running and enter step 4; Step 8: Normal valve control, go to step 2; Step 9, the central controller determines whether C1≥C2 is established. If it is established, it enters step 10, otherwise it enters step 8, where C1 is the actual change value of the water temperature within the Tm time, C2 is the set change value of the water temperature within the Tm time, and the value range of C2 is 0-5°C; Step 10: The operating frequency of the current compressor is reduced by one gear every 5 minutes, and then the process goes to step 7.

2. The method for suppressing frost formation in a heat pump according to claim 1, characterized in that In step six, when B1-B2≤0, the value of ΔT is 0; when 0>B1-B2≥0.2, the value of ΔT is 0.5; when 0.2>B1-B2≥0.4, the value of ΔT is 1; when B1-B2>0.4, the value of ΔT is 1.5.

Images