JPS61128068A - Defrostation control system of heat pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a defrosting control system for a heat pump characterized by an operating method before defrosting.

[Technical Background of the Invention] Conventionally, in this type of air conditioning crime, when the temperature of the outdoor heat exchanger falls below a certain value at a predetermined defrosting timing during heating operation, the outdoor heat exchanger is charged with high temperature. The outdoor heat exchanger is defrosted by supplying high-pressure refrigerant. In this case, the main defrosting method is to reset the four-way valve to cancel the heating cycle and temporarily create a cooling cycle, which uses the input of the compressor and heat absorption from the indoor heat exchanger to absorb heat from the outdoor heat exchanger. A reverse defrost system that supplies high-temperature, high-pressure refrigerant to the exchanger and a refrigerant bypass circuit for the heat exchanger outside the seedlings are installed, allowing the compressor input and There is a hot bypass defrosting method that supplies high-temperature, high-pressure refrigerant to an outdoor heat exchanger using accumulated heat. In the case of hot bypass defrosting, as a method of storing heat in the compressor before defrosting, the temperature of the outdoor heat exchanger is detected and the output of the indoor fan is reduced or turned off depending on the detection result. te 11,
1. There was a method of uniformly reducing the opening degree of the electric expansion valve by a certain value from the valve opening degree at the start of defrosting preparations to store heat in a compressed manner.

[Problems with the background art] However, the former method described above, which detects the temperature of the outdoor heat exchanger and reduces or turns off the indoor fan output,
It is not possible to increase the amount of heat storage, and a sufficient defrosting effect cannot be obtained. In addition, the latter method of narrowing the opening degree of the electric expansion valve by a certain value is useful when the output of the compressor is low before defrosting preparations start!
It! 7. The opening degree of the expansion valve was extremely narrowed, resulting in excessive heat accumulation in the compressor, resulting in a decrease in the performance of the air conditioner and the blowing pressure, which could impede the reliability of the compressor.

[Object of the invention] This invention was made in view of the above-mentioned circumstances.
This prevents a decrease in heating capacity during preparation for defrosting, and also reduces pressure
An object of the present invention is to provide a defrosting system for a heat pump that can sufficiently store heat while improving the reliability of the machine.

[Summary of the Invention] That is, the present invention detects the operating frequency, the valve opening degree of the electric expansion valve, and the temperature of the outdoor heat exchanger before preparation for defrosting, and detects the operating frequency and the electric expansion valve based on the detection results. The opening degree of the expansion valve is variably set.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows a refrigeration cycle diagram of the m-type heat pump defrost compressor of the present invention. During normal heating operation, the refrigerant is compressed by the compressor 11 as shown by the solid arrow in the figure, and is then passed through the four-way valve 12. The heat is condensed in the indoor heat exchanger 13 and radiated to the indoor air. After that, it is expanded with the electric expansion valve 14, and! The external heat exchanger 15 absorbs heat from the outdoor air and transfers it to the four-way valve 12.
The pressure reaches the 1 pressure regulator m machine 11 again via the . At the refrigerant outlet of the outdoor heat exchanger 15! A temperature sensor 1G that detects the temperature of the external heat exchanger 15 is provided. The opening degree of the electric expansion valve 14 is controlled by a microcomputer (rMJ in the figure) 17. In addition, the compressor 11 is an inverter circuit (represented as rlNVJ in the figure).
18, this inverter circuit 1
8 changes the generated frequency rounding voltage according to the difference between the changing temperature and the set temperature, that is, the heating load, and thereby changes the rotation speed of the compressor motor to obtain the optimal heating capacity corresponding to the load. It is something to do.

During the defrosting operation, the refrigerant circulation cycle is one in which the refrigerant is circulated from the compressor 11 to the outdoor heat exchanger 15 via the two-way valve 19, as shown by the broken line arrow in the figure;
From indoor heat exchanger 13 through four-way valve 12, electric #I!
Hot air bypass defrosting consists of two cycles: a normal heating cycle in which the compressed wire 11 is circulated through the outdoor heat exchanger 15 through the i-valve 14, and again through the four-way valve 12.

The operation of the above embodiment will be explained below.

Figure 2 shows the details of the control during the above defrosting operation.
compression! ! The outdoor heat exchanger 1 is detected by the operating frequency of 111, the valve opening of the electric expansion valve 14, and the temperature sensor 16.
Three temperature signals of 5 are input to the microcomputer 1γ. The microcomputer 17 performs calculations in the calculation section 171 based on these input data, and determines the operating frequency of the compression e 111 and the valve opening degree of the electric expansion valve 14 during defrosting preparation according to the calculation results.

The third factor indicates the operating status of each part from before the preparation for defrosting operation until the completion of defrosting. When preparing for defrosting operation, the operating frequency of the compressor 11 increases as shown in (a). At the same time, as shown in (d), the electric expansion valve 1
4 is narrowed down to a constant value.

As a result, the amount of refrigerant flowing into the outdoor heat exchanger 15 decreases, the refrigerant absorbs heat, the temperature of the compressor 11 rises, and the concentration of the outdoor heat exchanger 15 reaches a constant value as shown in (g). Rise.

Thereafter, when the defrosting operation is actually started, both the two-way valve 19 shown in (C) and the electric expansion valve 14 shown in (d) are fully open. At the same time, as shown in (e), the output of the indoor fan that promotes heat exchange in the indoor heat exchanger 13 is reduced, and as shown in (f), the output of the outdoor fan that promotes heat exchange in the outdoor heat exchanger 15 is reduced. Output is turned off. Therefore, in the outdoor heat exchanger 15, the refrigerant that has passed through the electric expansion valve 14 without radiating much heat in the indoor heat exchanger 13 and the compressed I! 11 through the bypass circuit via the two-way valve 19, the temperature rises as shown in (g),
The defrosting operation will be performed to melt the frost that has adhered.

FIG. 4 is a flowchart showing the contents of the operation process when controlling the operating frequency of the compressor 11 and the valve opening degree of the electric expansion valve 14 before preparing for defrosting as described above. When the operation starts, first, as shown in step 801, the outdoor heat exchanger 1
It is determined based on the detection result of the temperature sensor 16 whether the temperature No. 5 (represented as rTeJ in the figure) is lower than a predetermined value at which the defrosting operation should be started, for example, -10°C. here,
If it is determined that the temperature is equal to or higher than 10° C., this step 801 is repeated again. Also, the temperature is -110℃
If it is determined that the operating frequency of the compression 1111 (rHzJ
) is lower than a specific value, for example, 60 hertz. This is determined by the microcomputer 17 based on a value set in advance within the operating frequency range of the compressor 11 (for example, 30 Hz to 120 Hz) and a detection signal from the inverter circuit 18. If it is determined that this is the case, then the process proceeds to step 803, where the amount of change in the valve opening degree (represented as rsGJ in the figure) of the electric expansion valve 14 is set to be narrower by a certain value, for example, 10, than the previous state. do. These 10
As shown in FIG. 5, this value is a value when the fully open state of the electric expansion valve 14 is 200 and the fully closed state is O.

Then, after setting the valve opening to be narrow, the operating frequency of the compressor 11 is set higher in the next step S04, and this process ends. In addition, step 802
If it is determined that the operating frequency is less than 60, then the process proceeds to step 305, where it is determined whether the valve opening of the electric expansion valve 14 is less than or equal to a specific value, for example 50, which is one-fourth of the opening. is determined by the microcomputer 17. If it is determined that the opening degree is larger than 50, it means that the valve opening degree is too large, and the process proceeds to step 803 described above. If it is determined that it is 50 or less, then the process proceeds to step 806, where the amount of change in the valve opening degree of the electric expansion valve 14 is set to "0", and then the process proceeds to step 304 described above.

As described above, in this embodiment, when the temperature detected by the temperature sensor 16 attached to the outdoor heat exchanger 15 reaches a predetermined value,
The previous operating frequency of the compressor 11 and the valve opening of the electric expansion valve 14 are memorized, and the operating frequency of the compression 1111 and the valve opening of the electric expansion valve 14 at the time of preparing for defrosting operation according to the conditions are stored. It is designed to be controlled by calculation.

[Effects of the Invention] As described above, the present invention not only improves the reliability of the compressor, but also prevents the heating capacity from decreasing during defrosting and semi-warming, thereby increasing the comfort of the living space. It is possible to provide a defrost control system for a heat pump that can be used as a heat pump.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention. The first cause is a configuration diagram of the refrigeration cycle and its surroundings, FIG. 2 is a diagram showing the control contents, and FIG. Timing chart showing the operating status of each part until completion, Part 4
The figure is a flowchart showing the processing contents of the operation, and FIG. 5 is a diagram explaining the valve opening degree value of the electric expansion valve. DESCRIPTION OF SYMBOLS 11... Compressor, 12... Four-way valve, 13... Indoor heat exchanger, 1i... Electric expansion valve, 15... Outdoor heat exchanger, 16... Temperature sensor, 17... ... Microcomputer, 171 ... Arithmetic unit, 18 ... Inverter circuit, 19 ... Two-way valve. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In a heat pump air conditioner having a variable capacity compressor and an electric expansion valve, the operating frequency before defrosting,
a detection means for detecting the valve opening degree of the electric expansion valve and the temperature of the outdoor heat exchanger, and calculating the operating frequency and the valve opening degree of the electric expansion valve at the time of defrosting preparation based on the detection signal of the detection means. A defrosting control method for a heat pump, comprising: a calculation means; and a setting means for variably setting the operating frequency and the valve opening of the electric expansion valve according to the calculation results of the calculation means.