JPS63169457A - Heat pump type air conditioner - 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 Field of Industrial Application The present invention relates to a heat pump type air conditioner that utilizes heat storage.

Conventional technology Conventionally, most defrosting methods for outdoor heat exchangers in air source heat pump air conditioners have been to switch a four-way valve to create a cooling cycle, with the outdoor heat exchanger serving as a condenser and the indoor heat exchanger serving as an evaporator. At this time, the indoor fan was stopped to prevent cold drafts. In this method,
Basically, the amount of refrigerant circulating during the refrigeration cycle is small and it is not expected that the compressor input will increase much, so the defrosting time will be longer and the indoor fan will stop for several minutes during defrosting, resulting in a lack of heating sensation. Users are not satisfied with the fact that comfort is impaired, and that it takes time for the temperature of the indoor heat exchanger to rise even after switching the four-way valve and returning to heating operation after defrosting operation is completed. It wasn't something.

In recent years, instead of the reverse cycle defrosting system which has such drawbacks, by providing a bypass circuit etc., the four-way valve remains in the heating cycle even during defrosting operation, and both the indoor heat exchanger and outdoor heat exchanger are operated. A continuous heating defrosting method has been proposed in which defrosting is carried out while maintaining a certain heating capacity by using a compressor as a condenser (for example, Japanese Utility Model Application No. 60-59042).

The conventional heat pump type air conditioner will be described below with reference to the drawings.

FIG. 4 shows a refrigeration cycle diagram in a first example of a conventional heat pump type air conditioner. In the figure, 1 is a capacity-controllable frequency variable compressor (hereinafter simply referred to as a compressor), 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a capillary, 5 is an outdoor heat exchanger, and 6 is a hot gas In the bypass circuit, 7 is a two-way valve, and 8 is a bypass capillary. In addition, 9 is an outdoor heat exchanger temperature sensor, and 1o is this sensor 9.
This is a defrosting control controller that defrosts the outdoor heat exchanger 5 by controlling the compressor 1, two-way valve 7, indoor/outdoor fan (not shown), etc. in response to signals from the controller.

The hot gas bypass circuit 6 includes a discharge pipe 8 of the compressor 1.

During normal heating operation, the two-way valve 7 is closed to form a heating cycle, but when frost formation on the outdoor heat exchanger 5 is detected by a signal from the outdoor heat exchanger temperature sensor 9 at low outside temperatures, the defrosting The compressor 1 is activated by issuing a command from the controller 10.
, the main body temperature of the compressor 1 is increased to store heat. After a predetermined period of time has elapsed, a command is issued from the defrost control controller 10 to set the compressor 1 to the maximum frequency, open the two-way valve 7, and direct most of the high temperature discharged gas through the hot gas bypass circuit 6 to the outdoor heat. It is guided to the inlet side of the exchanger 5. At the same time, the remainder of the high-temperature discharged gas is passed through the four-way valve 2, indoor heat exchanger 3, and capillary 4 in the same way as during heating operation, and a slight heating operation is continued, and hot gas bypass is performed at the inlet of outdoor heat exchanger 5. It is made to merge with the refrigerant that has passed through the circuit 6. After this combined refrigerant defrosts the outdoor heat exchanger 5 with its own heat of condensation, it returns to the compressor 1 via the four-way valve 2 and completes the defrosting cycle.

In this way, defrosting can be performed while the heating cycle is still in progress, making it possible to improve comfort during defrosting.

Figure 5 shows the second part of a conventional heat pump air conditioner.
The refrigeration cycle diagram in the example is shown. In this example, a bypass circuit 11 that bypasses the capillary 4 is provided in place of the hot gas bypass circuit 6. and,
The bypass circuit 11 is equipped with a two-way valve 12 and a check valve 13.

During defrosting, the two-way valve 12 is opened to allow most of the refrigerant to pass through the bypass circuit 11, thereby increasing the refrigerant pressure in the outdoor heat exchanger 5 and reducing both the indoor heat exchanger 3 and the outdoor heat exchanger 5. By acting as a condenser, it is connected in a heat exchange manner similar to the effect explained in the first example, storing heat in the heat storage tank during heating operation, and using that heat during defrosting operation to quickly eliminate frost. A method capable of melting has also been proposed (for example, Japanese Patent Publication No. 54-38737).

Problems to be Solved by the Invention However, the above method has the following problems.

FIG. 6 shows the relationship between the amount of restriction of the bypass capillary, the defrosting time, and the heating capacity during defrosting operation in the first example of the conventional heat pump type air conditioner shown in FIG.

As is clear from the figure, if the amount of restriction of the bypass capillary 8 is increased, the amount of refrigerant circulated through the indoor heat exchanger 3 during defrosting operation will increase, and the pressure will also rise, so the heating capacity will increase. Since the pressure of the refrigerant passing through the outdoor heat exchanger 5 decreases and the condensing capacity decreases, the defrosting time becomes longer.

Therefore, in order to finish defrosting in a short time, it was not possible to increase the heating capacity. For example, most manufacturers of 1 horsepower class heat pump air conditioners are equipped with a control device that keeps the total current below 20A, and in this case, the amount of heat given to the refrigerant out of the input to the compressor is: As a result of the inventors' experiments, at most 1300k
Cal/h.

Assuming that defrosting is completed in 5 minutes, the amount of heat given to the refrigerant from the compressor input during this time is 108 kcal. Assuming that the compressor weight is tohg, the specific heat is 0.1, and the compressor body temperature drops by 30° C. during defrosting operation, a heat amount of 30 koal is given to the refrigerant. Mainly, a total of 138 koal of heat from these two amounts of heat is given to the refrigerant. On the other hand, if the amount of frosting is 900g, defrosting requires 72kcal.
of heat is used and the remaining (138-72) kcal of heat is available for space heating. This is 792 per unit time
kcal/h Furthermore, the reliability of the compressor was also low because the compressor body was used as a heat storage body and the refrigerant with low dryness was sucked in to remove heat from the compressor body.

In the case of the second example shown in FIG. 5 as well, the heating capacity during defrosting operation was low and had the same problem as shown in the first example. Furthermore, in the second example, in the case of a separate type heat pump air conditioner that connects the indoor unit and outdoor unit with connecting piping, the frequency of compressor 1 may be increased to increase the amount of refrigerant circulation, or the connecting piping may be made longer. When this happens, all the refrigerant passes through, so the pressure loss in the connecting pipe connecting the outlet of the indoor heat exchanger 3 and the inlet of the bypass circuit 11 increases, and the pressure of the refrigerant passing through the outdoor heat exchanger 5 decreases. There have been problems in that the condensing ability is reduced, resulting in a longer defrosting time or inability to defrost.

Instead of absorbing heat from inside the room, the stored heat was taken. Therefore, with this method, it is possible to shorten the defrosting time and prevent cold air from blowing into the room during defrosting operation, but it is not possible to heat the room during defrosting operation, and it is difficult to store heat in the heat storage tank. Since it uses an electric heater,
There was a problem in that energy efficiency during heating operation decreased.

By utilizing this heat during defrosting operation, the present invention provides a heat pump type air conditioner that performs defrosting while maintaining high heating capacity, and has high compressor reliability and energy efficiency.

Means for Solving the Problems In order to solve the above problems, the heat pump air conditioner of the present invention has a refrigerant circuit that connects a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducer, an indoor heat exchanger, etc. are arranged interchangeably, a bypass circuit that bypasses the pressure reducer is provided, a refrigerant flow path between the pressure reducer and the bypass circuit can be switched by a flow path switching means, and the bypass circuit and the heat storage tank are connected to each other. They are connected for heat exchange.

For production The present invention has the following effects through the above means.

In other words, by arranging a heat storage tank around the compressor for heat exchange, waste heat from the compressor can be recovered during heating operation, stored in the heat storage tank, and this heat can be used to feed the refrigerant again. This makes it possible to improve energy efficiency. In addition, a bypass circuit is installed that bypasses the pressure reducer and is connected to the heat storage tank for heat exchange. During defrosting operation, refrigerant flows through the bypass circuit and exchanges heat with the heat storage material in the heat storage tank, resulting in high heating capacity. It is possible to perform defrosting operation while maintaining the temperature of the compressor, and the dryness of the refrigerant sucked into the compressor can be maintained at a high level, so that the reliability of the compressor is also high. Furthermore, even if the separate tie pressure loss is large and the pressure of the refrigerant passing through the outdoor heat exchanger is low, defrosting is possible because the refrigerant in the superheat region can be used.

EXAMPLE Hereinafter, the present invention will be described with reference to FIG. 1 of the accompanying drawings showing an example thereof.
This will be explained with reference to FIG. In describing this embodiment, parts having the same functions as those of the conventional system shown in FIGS. 4 and 5 are given the same numbers and their explanations will be omitted.

FIG. 2 is a schematic cross-sectional view of the surroundings of the compressor 1 shown in FIG.

In the figure, 14 is a bypass circuit that bypasses the capillary 4, and this bypass circuit 14 includes a two-way valve 15,
A check valve 16 and a heat exchanger 17 are provided. Also, 1
8 is a heat storage tank, and this heat storage tank 18 is arranged around the compressor 1 in contact with it so that heat can be exchanged, and the inside is filled with a latent heat storage material (NaCH3CO0.3H20) 19, and this heat storage tank 18 is The heat exchanger 17 is arranged so as to be able to exchange heat with the material 19. Then, it is further surrounded by a heat insulating material 20.

In this single refrigerant container, during heating operation, the two-way valve 15
is in a closed state, and the refrigerant discharged from the compressor 1 flows through the four-way valve 2, the indoor heat exchanger 3, the capillary 4, the outdoor heat exchanger 5, and the four-way valve 2, and is sucked into the compressor 1. At this time,
With the above-described structure, it is possible to store heat, which was conventionally radiated from the compressor 1 to the outside air, in the heat storage tank 18.

Next, during defrosting operation, the two-way valve 15 is opened.

As a result, the refrigerant discharged from the compressor 1 is transferred to the four-way valve 2.
After being used for heating, a small amount of the refrigerant flows through the capillary 4 to the outdoor heat exchanger 5, and most of the remaining refrigerant flows into the bypass circuit 14 and is used for heating. It flows through the valve 15 to the heat exchanger 17, removes heat from the heat storage material 19, passes through the check valve 16, joins with the refrigerant that has passed through the capillary 4, and flows to the outdoor heat exchanger 5. and,
After being used for defrosting, it passes through a four-way valve 2 and is sucked into the compressor 1.

FIG. 3 is a diagram showing the refrigeration cycle of the heat pump type air conditioner shown in FIG. 1 during defrosting operation on a Mollier diagram. The symbol gmg in the figure is a in Figure 1.
- shows the state of the refrigerant at position g. First, compressor 1
The refrigerant compressed in (a-b') is used for heating in the indoor heat exchanger 3 and condenses (C→d), and the pressure decreases due to pressure loss when passing through connecting pipes, etc. (d-,). , the heat exchanger 17 of the bypass circuit 14 removes heat from the heat storage material 19 (, -
f) is used for defrosting in the outdoor heat exchanger 5 and condenses f-
g), passes through the four-way valve 2 and is sucked into the compressor 1 (g
"a). In this way, the refrigerant (d) that is condensed when used for heating takes heat from the heat storage material 19 and its enthalpy is raised to (fl) again, so even if the heating capacity is large, it can be defrosted in a short time. It is possible to finish.

Here, to show an example of the inventors' experimental results, the compressor input during heating operation was 1700 W (1462 keat/h).
In this case, in the conventional method, 1250 kcal/h of heat was given to the refrigerant, and 212 kcal/h of heat was radiated to the outside air. On the other hand, by using the structure shown in this example, 150 kaal/h, which is about 70% of the 212 kaal/h
It was possible to recover kcal/h of heat and store it in the heat storage tank 18.

If you fill it with 2.5J, it will give you 150kcal in 1 hour.
of heat can be stored. If all of this can be used during defrosting operation, the amount of heat given to the refrigerant is the amount of heat given from the compressor input explained in the conventional example, 108kca.
Add 150 kcal to 1 to get 258 keel. On the other hand, since the amount of heat used for defrosting is 72 kcal, the remaining amount of heat of 186 kcal can be used for heating. Since this is 2232 kcal/h per unit time, sufficient indoor comfort can be maintained.

In this way, the heat that was conventionally radiated to the outside air from the compressor can be recovered and used for defrosting, thereby increasing energy efficiency. Furthermore, since the refrigerant used for defrosting in the outdoor heat exchanger 5 is mostly in the state of superheated gas (f-"a), the compressor frequency may be increased to increase the amount of refrigerant circulation. By lengthening the piping connected to the connection, the pressure loss of d-・ increases, and f
-e Even if the pressure of the H refrigerant decreases, defrosting can be performed. Furthermore, since the refrigerant sucked into the compressor (ship) can be kept highly dry, defrosting operation with high reliability of the compressor can be performed.

In this example, the flow path switching means increases the amount of bittern recovered, but even if no insulation is provided, the amount recovered decreases, the defrosting time increases, and the heating capacity during defrosting decreases. However, the effects of the present invention can be obtained.

In addition, the heat storage material [NaCH3COO used in this example]
Materials other than 3H20 may be used. Furthermore, the same effect can be obtained without using a variable capacity compressor.

Effects of the Invention As described above, the heat pump type air conditioner of the present invention can improve energy efficiency by arranging a heat storage tank around the compressor for heat exchange. In addition, a bypass circuit is installed that bypasses the pressure reducer and is connected to the heat storage tank for heat exchange.
During defrosting operation, by flowing refrigerant through the bypass circuit and exchanging heat with the heat storage material in the heat storage tank, defrosting operation can be performed while maintaining high heating capacity, and compressor reliability is also improved by outdoor heat exchange. It has the effect of being able to defrost even if the pressure of the refrigerant passing through the container is low.

[Brief Description of the Drawings] Figure 1 is a refrigeration cycle diagram of a heat pump air conditioner according to an embodiment of the present invention, Figure 2 is a schematic cross-sectional view of the area around the compressor in Figure 1, and Figure 3 is the same diagram. A characteristic diagram showing the refrigeration cycle of a heat pump air conditioner in a Mollier diagram.
FIG. 4 is a refrigeration cycle diagram in a first example of a conventional heat pump type air conditioner, and FIG. 5 is a characteristic diagram showing the relationship between the amount of heat pump type air conditioner, defrosting time, and heating capacity. 1... Compressor, 2... Four-way valve, 3...
...Indoor heat exchanger, 4...Capillary (pressure reducer), 5...Outdoor heat exchanger, 14...
・Bypass circuit, 15... Two-way valve (flow path switching means), 17... Heat exchanger, 18... Heat storage tank, 19... Heat storage Material, 20... Insulation material. Name of agent: Patent attorney Toshio Nakao and one other name
3 diagram

Claims (1)

[Claims] A refrigerant circuit is constructed by connecting a compressor, a four-way valve, an outdoor heat exchanger, a pressure reducer, an indoor heat exchanger, etc., and a heat storage tank filled with a heat storage material is placed around the compressor. A bypass circuit is provided for heat exchange with the compressor and bypasses the pressure reducer, and a refrigerant flow path between the pressure reducer and the bypass circuit can be switched by a flow path switching means, and the bypass circuit and the bypass circuit A heat pump type air conditioner in which the heat storage tank is connected in a heat exchange manner.