JPS583014Y2 - refrigeration cycle - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a refrigeration cycle that defrosts while performing heating operation in the initial stage of frost formation.

FIG. 1 shows the flow of refrigerant during heating operation in a conventional heat pump near conditioner, and FIG. 2 shows the flow of refrigerant during defrosting operation.

In other words, during heating operation, as shown by the solid line arrow in Figure 1, the compressor 1
The high-pressure, high-temperature refrigerant gas discharged from the 4-way valve 2 enters the indoor heat exchanger 3, where it becomes a condensed liquid due to the forced ventilation of the indoor fan 4, which passes through the check valve 5 and enters the throttle 8.
The gas enters the outdoor heat exchanger 9, where it is evaporated by the outdoor fan 10, becomes a low-pressure gas, passes through the four-way valve 2 again, and is sucked into the compressor 1.

Refrigerant does not flow through the throttle 6 and check valve I during heating operation, but flows during cooling and defrosting.

When the outside temperature decreases and frost builds up on the outdoor heat exchanger 9, the amount of heat pumped up by the outdoor heat exchanger 9 decreases, the refrigerant pressure decreases, and the refrigerant saturation temperature also decreases.

A temperature sensing part of a defrost detector 11 is brought into contact with the inlet pipe to the outdoor heat exchanger 9, and when the refrigerant temperature falls below the set temperature, the defrost detector 11 is activated and the four-way valve 2 is activated. As a result, the refrigerant circuit enters cooling operation, and the refrigerant flows as shown by the broken line arrow in FIG.

That is, after the high-pressure and high-temperature refrigerant gas discharged from the compressor 1 passes through the switched four-way valve 2, it enters the outdoor heat exchanger 9 and is defrosted using the heat possessed by the refrigerant.

After that, it passes through the check valve 7 and is adiabatically expanded by the throttle 6 and enters the indoor heat exchanger 3, where it is normally used to prevent cold draft (cold air suddenly blown into the room and causing discomfort to the occupants). , the indoor fan 4 is stopped, the refrigerant exchanges heat by the amount of natural convection, and is sucked into the compressor 1 through the four-way valve 2.

When the frost on the outdoor heat exchanger 9 melts and the temperature of the temperature sensing part of the defrost detector 11 rises, the four-way valve 2 switches and returns to the heating operation shown in Figure 1. There was a drawback.

During the above-mentioned defrosting operation and for some time after the return, heating operation is not performed indoors, and during the time in the trench where frosting progresses and defrosting operation begins, the amount of heat pumped up by the outdoor heat exchanger 9 is It has been gradually decreasing, and there was a drawback that sufficient heating operation was not carried out.

This invention does not perform defrosting operation by turning on and off, but by performing defrosting while performing heating operation at the early stage of frost formation, the low-pressure refrigerant circuit (from the heating throttle outlet to the compressor population 1) during heating operation is The system detects the pressure or temperature of the refrigerant that is being used, and when this falls below a predetermined value, reduces the amount of throttling by the heating diaphragm and provides heat to the outdoor heat exchanger to defrost or prevent frost formation while running the heating operation. It is designed to prevent this from happening and is used in air heat source type separate type heat pump near conditioners.

The present invention will be explained based on FIG. 3 (illustrative diagram of a heating operation refrigerant circuit according to the present invention) and FIG. 4 (illustrative diagram of an electric circuit).

During heating operation, high-pressure, high-temperature gas compressed and discharged by the compressor 1 passes through the four-way valve 2, is cooled by the indoor fan 4 in the indoor heat exchanger 3, becomes condensed liquid, passes through the check valve 5, and enters the throttle 8.
It expands adiabatically and becomes low pressure, takes in heat by the outdoor fan 10 in the outdoor heat exchanger 9, evaporates, becomes a low pressure gas, passes through the four-way valve 2, and is sucked into the compressor 1.

The point that the check valve 7 and throttle 6 flow during cooling operation is as follows.
This is the same as the conventional one (FIG. 1).

However, in the embodiment of the present invention shown in FIG. 3, frost formation is prevented or removed without switching the four-way valve 2.

For this reason, a pressure switch 1 is installed in the piping between the heating throttle 8 and the compressor 1 to detect the low pressure of the refrigerant.
2 is included.

The pressure switch 12 is activated to excite the relay 20 and the solenoid valve 13 when the pressure falls below a set pressure (described later).

The electromagnetic valve 13/d throttle 14 and the heating throttle section 8 are provided in parallel in a series circuit.

As mentioned above, during heating operation, when the refrigerant pressure between the heating throttle 8 and the compressor 1 reaches the set pressure or less, the pressure switch 12 is activated and the relay 20 shown in FIG. 4 is energized, the relay contact 21 is activated. As a result, electricity begins to flow through the indoor fan 4 through the resistor 22, so that the fan 4
The rotation speed of the indoor heat exchanger 3 decreases (extremely low speed rotation), and the condensing pressure of the indoor heat exchanger 3 increases.

At the same time, the electromagnetic valve 13 is energized to open the circuit, so that the liquid refrigerant that has passed through the check valve 5 passes through the electromagnetic valve 13 and the throttle 14 as indicated by arrow MO.

Since the flow rate of the refrigerant decreases, the overall amount of throttling decreases, and the low pressure of the refrigerant entering the outdoor heat exchanger 9 increases, causing frost formation. prevent or eliminate

Then, the evaporation pressure eventually rises and the pressure switch 12
When the heating is restored, normal heating operation resumes.

If the setting pressure of the pressure switch 12 is set to, for example, 4 kg/crit G, the saturation temperature will be -0.2°C, and it will work as a frost prevention.
If set to g/dG, the saturation temperature will be 3°4°C,
Defrost partially frosted items.

In the embodiment shown in FIG. 3, the pressure switch 12 is provided as described above, but instead of this, the defrost detector 11 shown in FIG.
It is installed at a position similar to the pressure switch 12 to detect the low temperature state of the refrigerant gas.

First, temperature detection is used instead of pressure detection.In this case, the pressure switch 12 shown in Fig. 4 is simply replaced with the defrost detector 11, and the effect is the same as when the pressure switch 12 is used. It is similar to

In short, the present invention is suitable for a heat pump type near conditioner, in which a solenoid valve 13 and an aperture 14 are connected in parallel to a heating aperture 8.
A series circuit is provided to detect the state of the refrigerant gas between the outlet of the heating throttle 8 and the inlet of the compressor 1, and to open the solenoid valve 13 when the state of the refrigerant gas is below a set value (pressure, temperature). This is a refrigeration cycle characterized by the following configuration.

That is, in the present invention, the refrigerant discharged from the compressor 1 during heating operation is circulated to the compressor 1 through the indoor heat exchanger 3, the heating throttle 8, and the outdoor heat exchanger 9 in this order. In the refrigeration cycle of the near conditioner, there is provided a detection device 12 for detecting the pressure or temperature of the refrigerant between the outlet of the heating throttle 8 and the inlet of the compressor 1, and a detection device 12 that receives a signal from the detection device 12. a solenoid valve 13 that opens when the pressure or temperature of the refrigerant falls below a predetermined value and closes when the pressure or temperature of the refrigerant reaches a predetermined value or more; It is characterized by comprising a series refrigerant circuit consisting of.

Therefore, (I) Defrosting is easy because defrosting is carried out at the early stage of the orthogonal process of frost formation.

(b) There is no switching between four-way valves, so there is no unpleasant noise.

([III) If the rotation of the indoor fan is reduced, there will be no cold draft.

(V) Capable of operation commensurate with the load.

M The degree of decrease in heating capacity that is seen in the direct process of frost formation, unlike conventional ones, is small.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams showing the flow of refrigerant during heating operation and cooling operation by switching the four-way valve in a conventional heat pump type near conditioner, respectively, and Figure 3 is a refrigeration cycle according to the present invention. FIG. 4 is a system diagram showing one embodiment of the present invention, and FIG. 4 is an explanatory diagram of an electric circuit diagram for opening and closing the electromagnetic valve in FIG. 1... Compressor, 3... Indoor heat exchanger, 8... Heating throttle, 9... Outdoor heat exchanger, 12... ...Detection device, 13...
Solenoid valve, 14... Throttle.

Claims (1)

[Scope of utility model registration request] In the refrigeration cycle of a near conditioner in which the refrigerant discharged from the compressor during heating operation is circulated to the compressor after passing through an indoor heat exchanger, a heating aperture, and an outdoor heat exchanger in this order, a detection device that detects the pressure or temperature of the refrigerant between the throttle outlet and the compressor inlet; A refrigeration cycle characterized in that it is equipped with a solenoid valve that closes when the above condition occurs, and a series refrigerant circuit that is interposed in parallel with the heating throttle and includes the solenoid valve and the throttle.