JPS5926203Y2 - Heat pump type refrigeration equipment - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a heat storage device that is incorporated into, for example, an air source heat pump type air conditioner.

First, an example of a refrigeration cycle of a conventional heat pump type air conditioner will be explained with reference to FIG.

The refrigeration cycle includes a compressor 1 connected to each other by piping,
Consisting of a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, a check valve 5, an expansion valve 6, a check valve 7, and an indoor heat exchanger 8, the heat exchanger 3
, 8, outdoor fan 9 and indoor fan 10, respectively.
is installed.

During heating operation, high-temperature, high-pressure refrigerant vapor discharged from the compressor 1 flows into the indoor heat exchanger 8 through the four-way valve 2.
Here, it exchanges heat with indoor air, condenses and liquefies, warming the air.

The liquid refrigerant passes through the check valve 7 and the expansion valve 4 and enters the outdoor heat exchanger 3 as a low-temperature, low-pressure refrigerant, where it receives heat from the outside air and evaporates.

During this action, frost gradually forms on the outer surface of the heat exchanger 3.

When a large amount of frost adheres, heat exchange performance decreases, leading to inefficient heating operation.

Therefore, once the heat exchanger 3 has a certain amount of heat, a so-called defrosting operation is performed in which the flow of refrigerant in the refrigeration cycle is changed to melt the frost.

During defrosting operation, the refrigerant flows through the compressor 1, the four-way valve 2, the outdoor heat exchanger 3, the check valve 5, the expansion valve 6, the indoor heat exchanger 8, the four-way valve 2, and the compressor 1 in this order.

Therefore, high-temperature refrigerant flows through the outdoor heat exchanger 3 to melt the adhering frost, while low-temperature refrigerant flows through the indoor heat exchanger 8, and while the refrigerant is evaporated by the indoor fan 10,
Cold air will be blown into the room.

If the fan 10 is stopped at this point, the problem of blowing out cold air seems to be solved, but the low-temperature refrigerant cannot be evaporated, making it impossible to form a smooth refrigeration cycle.

Some refrigeration cycles incorporate a heat storage device so that even if the indoor fan 10 is stopped during defrosting operation, the refrigeration cycle can still be smoothly formed.

An example of this will be explained with reference to FIG.

In this figure, the same reference numerals as in FIG. 1 represent the same things.

A heat storage device 11 having a built-in heat exchanger 12 for storing and releasing heat is installed between the four-way valve 2 and the indoor heat exchanger 8.

Other details are the same as those in FIG. The high-temperature refrigerant discharged from the compressor 1 during heating operation gives heat to the medium in the heat storage device 11 through the heat exchanger 12 .

During the defrosting operation, the low-temperature refrigerant that could not be evaporated because the fan 10 is stopped receives heat from the heat storage medium in the heat storage device 11, evaporates, and returns to the compressor 1.

The smooth operation of the refrigeration cycle is achieved by the aforementioned heat absorption and heat radiation.

However, in an actual device, there is a problem of time.

In other words, the weather conditions where frost is most likely to form (outside temperature 0 to 2
Even if the heating system is operated at a temperature of 90 to 100% relative humidity, it takes several tens of minutes before the heating capacity suddenly decreases due to frost formation.

Since the defrosting operation is switched to after the heating capacity has decreased, heat storage in the heat storage device 11 can be carried out gradually over several tens of minutes, and the heat exchanger 12 in the heat storage device 11 is relatively small. That's fine.

Conversely, if heat is stored rapidly, the heating capacity will decrease during that time.
The room doesn't get warm.

Since it is not possible to heat the room during defrosting operation, it is better to keep defrosting operation as short as possible.

For general heat pump air conditioners, the defrosting operation time is 3 to 1
It takes about 0 minutes.

Therefore, the heat radiation from the heat storage device 11 needs to be completed within a few minutes during defrosting.

In other words, the heat storage rate of the heat storage device is approximately 10 times higher than the heat release rate.
Desirably twice as large.

Let's now consider a heat storage device that uses water as a heat storage medium and uses its sensible heat.

The amount of heat storage Qst and the amount of heat radiation Qra are expressed by equations (1) and (2).

QSt=1・Fl・△t1・△τ1・・・・・・(1
)Qra=2・F2・△t2・△τ2・・・・・・(
2) Here, K1, K2: heat passage rate F1 of the heat exchanger 12
, F2: Heat exchanger heat transfer area Δt1, Δt2: Temperature difference between water and refrigerant Δτ1: Heating operation time Δτ2: Defrosting operation time.

Qst and Qra are generally equal.

The heat transfer rate is given when the heat exchanger and the heat exchange form are determined, and is 2 for K+-=.

The refrigerant temperature during heat storage is approximately 90°C, and that during heat dissipation is approximately 10°C.
It is.

The water temperature increases from 10°C to 90°C during heat storage, and decreases from 90°C to 90°C during heat dissipation.

Therefore, △1. =12. From the above, Fl・△τ=F2・△τ2 (3) is desirable, but conventionally it is 371 (5 to 10)・△τ2 (4) Nevertheless, F1=F2...(5).

The object of this invention is to provide a heat pump type refrigeration system having a heat storage device that can reduce the heat transfer area of the built-in heat exchanger during heating operation and increase the heat transfer area of the heat exchanger during defrosting operation.

Next, one embodiment of this invention will be explained with reference to FIG.

In this embodiment, the ratio of heat transfer areas F1 and F2 is 1:2.

A heat exchanger 12 in which flow paths are connected to each other in the heat storage device 11
A and 12B are built in, and a check valve 13 that allows flow in the direction of the arrow is attached to one end of the heat exchanger 12A.

During heating operation, the high temperature refrigerant discharged from the compressor flows from the B side to the A side, and only the heat exchanger 12B works.

Heat exchangers 12A and 12C are closed by check valves 13.

In this case, since the area F1 of the heat exchanger is relatively small with respect to the amount of heat storage medium, the heat storage time Δτ1 becomes long.

Since the heat storage rate is slow, a large amount of heat does not transfer to the heat storage device immediately after the heating operation starts, so the indoor air can be sufficiently warmed.

During defrosting operation, low-pressure, low-temperature refrigerant is made to flow from side A to side B.

In this case, the three heat exchangers 12A and 12B work together, increasing the heat transfer area.

As a result, the low temperature refrigerant can be rapidly superheated, and this heat and the compressor input can melt the frost in a short time.

Next, an embodiment of the heat pump type refrigeration apparatus according to the present invention will be described.

FIG. 4 shows a refrigeration cycle in which the heat storage device 11 of FIG. 3 is installed between the four-way valve 2 and the indoor heat exchanger 8. represent the same thing.

One end side of the heat exchanger 12B of the heat storage device 11 is an expansion valve 4.6.
A defrosting expansion valve 14 and a solenoid valve 15 are suspended in the pipe between the pipes, and the other end is connected to a heat exchanger 12A and an indoor heat exchanger 8.
It is suspended in a conduit between the

One end of the heat exchanger 12A is connected to the switching port of the four-way valve 2, and the other end is connected to the indoor heat exchanger 8.

Other details are the same as in Figure 1. Solenoid valve 1 only during defrosting operation
5 is opened, and the refrigerant that has become low temperature and low pressure by the expansion valve] 4 is transferred to the heat exchanger 12B.

12A, absorbs heat from the heat storage device 11, and evaporates.

In addition, some refrigerant flows through the expansion valve 6. It flows through the indoor heat exchanger 8 to the heat exchanger 12A.

During heating operation, the check valve 13 works to close the heat exchanger 12B,
Defrosting expansion valve 14. Refrigerant does not flow through the pipe line including the solenoid valve 15.

During cooling operation, the solenoid valve 15 is closed and no refrigerant flows through the pipe.

As explained above, according to this invention, in a heat pump type air conditioner, the heat exchange area in the heat storage device is changed during heating and defrosting, and heat can be gradually stored during heating, and as a result, There is no need to reduce the rise characteristic of the temperature of the air blown into the room immediately after the heating operation starts.

Further, during defrosting, heat can be rapidly given from the heat storage medium to the refrigerant, and as a result, defrosting of the outdoor heat exchanger can be completed quickly.

This idea can also be applied to refrigerator/refrigerator units that employ a reverse cycle defrosting system, in which heat is gradually stored in the heat storage device while the refrigerator is being cooled, and defrosting is performed during reverse cycle operation. At this time, the refrigerant rapidly receives heat and can melt the frost that has formed on the internal heat exchanger.

Therefore, the rise in internal temperature during defrosting can be kept to a minimum.

[Brief explanation of the drawing]

Figure 1 is a system diagram showing an example of the refrigeration cycle of a conventional heat pump type air conditioner, Figure 2 is a system diagram showing the refrigeration cycle of a heat pump type air conditioner incorporating a conventional heat storage device, and Figure 3 is a system diagram showing an example of the refrigeration cycle of a conventional heat pump type air conditioner.
The figure is a sectional view showing a different embodiment of the heat storage device according to this invention, and FIG. 4 is a system diagram showing a refrigeration cycle of a heat pump air conditioner incorporating the heat storage device of FIG. 3. 1... Compressor, 2... Four-way valve, 3...
...Outdoor heat exchanger, 8...Indoor heat exchanger,
11... Heat storage device, 12A~12B...
Heat exchanger, 13... Check valve, 14...
Defrosting expansion valve, 15... Solenoid valve.

Claims (1)

[Scope of Claim for Utility Model Registration] In a heat pump type refrigeration system in which a compressor, a four-way valve, an indoor heat exchanger, a pressure reducing device for cooling and heating, and an outdoor heat exchanger are sequentially connected via piping, the four-way valve and the indoor heat exchanger In between, a heat storage device is installed with a built-in pipe line that connects these two devices as a first heat exchanger, and a high-pressure liquid pipe line that connects the air conditioning/heating pressure reducing device and a pipe that connects the heat storage device and the indoor heat exchanger are installed. A bypass pipe connects an on-off valve that is opened only during defrosting, a pressure reducing device, a second heat exchanger built into the heat storage device, and a check valve, and during heating operation, the above-mentioned Only the first heat exchanger is used as a heat storage material heater, and the second heat exchanger is used during defrosting operation. A heat pump type refrigeration device characterized in that first heat exchangers are connected in series and a side heat exchanger is used as a refrigerant evaporator.