KR100344787B1 - Heat Pump - Google Patents

Abstract

The present invention relates to a heat pump having a minimizing heat loss and having a simple structure to prevent freezing. The present invention relates to a heat pump including a compressor, a four-way valve, an outdoor unit, an expansion valve, and an indoor unit, which are sequentially connected. A first branch pipe branched in parallel from the refrigerant pipe between the expansion valve and the indoor unit and connected to the auxiliary heat exchanger; An auxiliary heat exchanger installed in the outdoor unit to prevent freezing of the outdoor unit by heat generation of the refrigerant introduced through the first branch pipe; The auxiliary heat exchanger is further provided with a second pump connected to the refrigerant pipe between the expansion valve and the indoor unit to circulate the refrigerant further comprises a heat pump.

Description

Heat Pump

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump, and more particularly, to a heat pump capable of efficiently removing freezing occurring in an outdoor unit of a heat pump.

In general, the refrigeration cycle consists of a compressor, a condenser, an expansion valve and an evaporator such that the evaporator absorbs heat from the hot portion and the condenser releases heat to the cold portion. Therefore, the use of the evaporator to absorb the heat of the hot portion can constitute a cooling device such as an air conditioner or a refrigerator, and can be used as a heating device (heat pump) if the condenser uses heat to discharge to the low temperature portion.

In addition, since the evaporator and the condenser are a heat exchanger, if the compressor, the evaporator, the condenser and the expansion valve are configured, and the refrigerant flow is selectively changed, the cooling operation and the heating operation can be realized as a single device (hereinafter referred to as a "heat pump"). have.

By the way. When the heat pump is used for heating operation, there is a problem in that freezing occurs in an outdoor unit that serves as an evaporator. Because the heating operation is usually performed during the winter season, the outdoor temperature of the outdoor unit is often below zero, especially in the cold region, since the ambient temperature is always below zero, condensate is generated in the outdoor unit serving as an evaporator, and the condensate is immediately Because it will freeze.

In addition, in the evaporator (heat exchanger), a plurality of metal plates (fins) are usually stacked, and a tube through which the coolant flows is installed vertically. Therefore, if freezing occurs between the pin ingot fins, the air is blocked and the loss of pressure increases, power consumption and noise increase, and heat exchange efficiency rapidly decreases.

Therefore, the outdoor unit should be prevented from freezing. One method is to perform a defrosting operation to cool the heat pump at a predetermined time interval. That is, the defrosting operation is the same as the cooling operation, thereby preventing freezing by allowing the outdoor unit to act as a condenser that radiates heat. However, this method has a problem that the heating efficiency is lowered because the defrosting operation at a predetermined time interval during the heating operation.

Therefore, a heat pump has been proposed in which a defrosting device is separately installed to allow defrosting operation while continuously performing heating operation. This will be described with reference to FIGS. 1 and 2 as follows.

The heat pump includes a compressor (1) for compressing a refrigerant, an indoor unit (2) and an outdoor unit (3) having internal heat exchangers (2a, 3a) installed in each of the indoor and outdoor spaces to exchange heat with air in each space; The four-way valve 4 and the expansion valve 6 which switch the circulation path of the refrigerant to the indoor unit 2 or the outdoor unit 3 according to the cooling and heating mode are provided.

In addition, an auxiliary heat exchanger 5 is installed in the outdoor unit 3 to prevent the outdoor unit 3 from freezing by allowing a high temperature refrigerant to flow therein, and between the auxiliary heat exchanger 5 and the expansion valve 6. Rectification means for controlling the refrigerant from the indoor unit 2 or the outdoor unit 3 to always pass through the auxiliary heat exchanger 5 is provided. In addition, a receiver 7 is provided between the auxiliary heat exchanger 5 and the expansion valve 6 to store the refrigerant and to flow the refrigerant from the auxiliary heat exchanger 5 toward the expansion valve 6. Each of these components is interconnected by a main refrigerant pipe (8).

On the other hand, the rectifying means is a closed circuit by a pair of first and second connecting pipes (10) (11) in parallel and the third, fourth connecting pipes (12) (13) connecting the two connecting pipes. . The first and second check valves 14 and 15 are installed in series on the first connecting pipe 10, and the third and fourth check valves 16 and 17 are installed on the second connecting pipe 11. Also, the first and second check valves 14 and 15 and the third and fourth check valves 16 and 17 are arranged in parallel.

The linkage between the rectifying means and the peripheral parts is as follows.

Among the rectifying means, between the first and second check valves 14 and 15 of the first connecting pipe 10 and the indoor heat exchanger 2, the first auxiliary refrigerant pipe 8a and the second connecting pipe 11 are formed. Between the third and fourth check valves 16 and 17 and the outdoor heat exchanger 3, the second auxiliary refrigerant tube 8b, the third connecting tube 12 and the auxiliary heat exchanger 5 are connected to the third auxiliary refrigerant tube (3). 8c), the fourth connecting pipe 13 and the expansion valve 6 are connected by the fourth auxiliary refrigerant pipe 8d, respectively.

Referring to the operation of the conventional heat pump described above is as follows.

First, the cooling mode will be described with reference to FIG. 1. The refrigerant compressed from the compressor 1 is directed to the outdoor unit 3 by the four-way valve 4, and then the second auxiliary refrigerant tube 8b → 2nd connecting pipe (11) → 3rd check valve (16) → 3rd connecting pipe (12) → 3rd auxiliary refrigerant pipe (8c) → 2nd heat exchanger (5) → receiver (7) → expansion valve (6) → 4th auxiliary refrigerant pipe (8d) → 4th connection pipe (13) → 2nd check valve (15) → 1st connection pipe (10) → 1st auxiliary refrigerant pipe (8a) → indoor heat exchanger (2) → four-way valve (4) → compressor (1). Therefore, the indoor unit 2 installed in the indoor space cools the room while absorbing the heat amount of the surrounding indoor air by the evaporation action, and the outdoor unit 3 functions to dissipate the heat amount of the refrigerant to the outside by the condensation action.

The case of the heating mode will be described with reference to FIG. 2.

The refrigerant compressed from the compressor (1) is directed to the indoor heat exchanger (2) by the four-way valve (4), and then the first auxiliary refrigerant pipe (8a) → the first connecting pipe (10) → the first check valve (14) → Third connection pipe (12) → Third auxiliary refrigerant pipe (8c) → Secondary heat exchanger (5) → Fluidizer (7) → Expansion valve (6) → Fourth auxiliary refrigerant pipe (8d) → It is circulated in the order of the four connecting pipes 13 → the fourth check valve 17 → the second auxiliary refrigerant pipe 8b → the outdoor heat exchanger 3 → the four-way valve 4 → the compressor 1. Therefore, the indoor unit 2 installed in the indoor space radiates heat energy for heating the room by the condensation action, and the outdoor unit 3 absorbs the heat amount of the external air by the evaporation action.

And, as can be seen in the flow of the refrigerant, the refrigerant from the indoor unit 2 serving as a condenser always prevents the outdoor unit 3 from freezing via the auxiliary heat exchanger 5.

However, the anti-icing device of such a heat pump had the following problems.

First, the conventional anti-icing device prevents freezing from occurring in the outdoor unit during the heating operation, but may lower the cooling efficiency during the cooling operation. This is because, during the cooling operation, the coolant passes through the freezing prevention device, and part of the coolant evaporates in the freezing prevention device. In other words, during the cooling operation, all of the refrigerant is preferably evaporated in the indoor unit. However, some of the refrigerant is evaporated in the icing preventing device, thereby lowering the cooling efficiency.

Second, the conventional freezing prevention device has a disadvantage in that the production cost and manufacturing process is complicated, the productivity is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a heat pump having a freeze preventing device capable of preventing freezing of an outdoor unit with a simple structure and efficiently.

In addition, the present invention is to provide a heat pump that can reduce the heat loss to improve the refrigeration efficiency or the coefficient of performance.

1 and 2 is a schematic view showing the configuration of a conventional heat pump, Figure 1 shows the flow of the refrigerant during the cooling operation and Figure 2 shows the flow of the refrigerant during the heating operation.

3 is a configuration diagram showing an embodiment of a heat pump according to the present invention.

4 is a configuration diagram showing another embodiment of the heat pump according to the present invention.

Explanation of symbols for main parts of the drawings

1. Compressor 2. Indoor unit

3. Outdoor unit 4. Four-way valve

6. Expansion valve 20. First branch pipe

21. Second branch 30. Auxiliary heat exchanger

40. Check Valve

In order to achieve the above object, the present invention is a heat pump including a compressor, a four-way valve, an outdoor unit, an expansion valve and an indoor unit are sequentially connected, branched in parallel in the refrigerant pipe between the expansion valve and the indoor unit A first branch pipe connected to the auxiliary heat exchanger; An auxiliary heat exchanger installed in the outdoor unit to prevent freezing of the outdoor unit by heat generation of the refrigerant introduced through the first branch pipe; The auxiliary heat exchanger is further provided with a second pump connected to the refrigerant pipe between the expansion valve and the indoor unit to circulate the refrigerant further comprises a heat pump.

Accordingly, the present invention provides a heat pump that is simple in structure and can prevent freezing of the outdoor unit and further reduce cooling efficiency.

Referring to Figure 3, it will be described a preferred embodiment of the heat pump according to the present invention.

The heat pump according to the present invention also has a compressor (1), an indoor unit (2) having an indoor heat exchanger (2a), an outdoor unit (3) with an outdoor heat exchanger (3a), and an expansion valve (6). And a four-way valve 4 for switching the flow of the refrigerant in the forward or reverse direction, and these are connected to form a refrigeration cycle (heat pump cycle).

In addition, an ice preventing device for preventing freezing from occurring in the outdoor unit 3 is configured. The ice protection device will be described in detail as follows.

The outdoor unit 3 is provided with an auxiliary heat exchanger 5 for preventing the heat exchanger 3 built in the outdoor unit from freezing, and one side of the auxiliary heat exchanger 5 is connected to the indoor unit 2, and The side is connected to the expansion valve (6).

In more detail, the first branch pipe 20 for sending a part of the refrigerant to the auxiliary heat exchanger 30 is formed at a predetermined position of the refrigerant pipe 200 connecting the indoor unit 2 and the expansion valve 6. In order to circulate the refrigerant exchanged with the outdoor unit 3 in the auxiliary heat exchanger 30 to the refrigerating cycle again, that is, to the expansion valve 6, a second branch pipe 21 is formed. Here, the first branch pipe 21 and the second branch pipe 21 are connected to the refrigerant pipes 200 and 200a connecting the indoor unit 2 and the expansion valve 6 to each other at a predetermined distance from each other. 200, 200a).

On the other hand, as shown in Figure 3, it is preferable to install a check valve 40 for flowing the refrigerant in only one direction in the second branch pipe 21 to prevent the back flow of the refrigerant. The check valve 4 may be provided in the first branch pipe 20.

Then, the flow rate adjusting means for adjusting the flow rate of the refrigerant branched to the refrigerant pipe (hereinafter referred to as "intermediate refrigerant pipe") 25 between the branch of the first branch pipe 20 and the return portion of the second branch pipe (hereinafter referred to as "intermediate refrigerant pipe"). It is also possible to provide 110 to appropriately adjust the amount of refrigerant flowing into the auxiliary heat exchanger 30.

In addition, the auxiliary heat exchanger 30 is preferably installed in the lower part of the heat exchanger 3 of the outdoor unit in view of the fact that the freezing phenomenon proceeds from the lower part of the heat exchanger 3a of the outdoor unit 3.

Referring to the operation of the heat pump according to the present invention described above are as follows.

First, in the cooling mode, the compressor (1) → four-way valve (4) → outdoor unit (3) → expansion valve (6) → indoor (2) → four-way valve (4) → compressor (1) Will be achieved. This circulation path is simplified as compared with the prior art it is possible to reduce the heat loss.

At this time, the refrigerant passing through the expansion means 6 may be introduced into the first and second branch pipes 20 and 21 in the process of flowing into the indoor unit 2, but the check valve 40 is provided in the branch pipe. It can be installed to prevent the backflow of the refrigerant.

On the other hand, in the heating mode, the compressor (1) → four-way valve (4) → the room (2) → the first branch pipe (20) → the auxiliary heat exchanger (30) → the check valve (40) → the second branch pipe (21). → expansion valve (6) → outdoor unit (3) → four-way valve (4) → compressor (1).

That is, when the heating operation is started, the refrigerant circulates in the order of the compressor 1, the indoor unit 2, the expansion valve 6, and the outdoor unit 3 to heat the room.

At this time, a part of the refrigerant flowing between the indoor unit 2 and the expansion valve 6 branches through the first branch pipe 20 and flows to the auxiliary heat exchanger 30. Freezing of the outdoor unit 3 is prevented by the heat generation of the refrigerant flowing through the auxiliary heat exchanger 30, and the refrigerant flows back into the refrigerant pipe 200a through the second branch pipe 21. Then, the branched refrigerant passing through the auxiliary heat exchanger 30 and the refrigerant flowing directly into the indoor unit 2 are combined with the refrigerant pipe 200a to flow to the expansion valve 6 to form a refrigeration cycle.

Therefore, according to the present invention, since only a part of the refrigerant having a refrigeration cycle is sent to the auxiliary heat exchanger, heat loss can be reduced. And since only the 1st branch office and the 2nd branch office are used, a structure becomes simple, and productivity can be improved.

Referring to Figure 4, another embodiment of the heat pump according to the present invention will be described.

This embodiment is identical in principle to the above-described embodiment. However, the length of the intermediate refrigerant pipe 25 between the first branch pipe 20 and the second branch pipe 21 without using a flow control means for separately controlling the amount of refrigerant branched to the auxiliary heat exchanger 30. It proposes a method that can control the amount of refrigerant to be branched by adjusting the. In addition, the present invention provides a method of controlling the amount of refrigerant diverged by adjusting the diameters of the first branch pipe 20 and the second branch pipe 21 and the diameter of the intermediate refrigerant pipe 25.

First, the relationship between the diameter of the intermediate refrigerant pipe 25 and the branch pipe is as follows.

The diameter of the intermediate refrigerant pipe 25 is preferably smaller than the diameter of the first and second branch pipes 20 and 21. The reason is that if the diameter of the intermediate refrigerant pipe 25 is larger than the diameter of the first and second branch pipes 20 and 21, the length L of the intermediate refrigerant pipe 25 should be long for the smooth branching of the refrigerant. If the length (L) of the intermediate refrigerant pipe (25) is long, a large amount of space is occupied when the heat pump is manufactured, which causes a problem that the appearance of the product is increased. Therefore, the diameter of the intermediate refrigerant pipe 25 is preferably smaller than the diameter of the first and second branch pipes 20 and 21.

The amount of the refrigerant branched to the auxiliary heat exchanger 30 by adjusting the length of the intermediate refrigerant pipe 25 while the diameter of the intermediate refrigerant pipe 25 is smaller than the diameter of the first and second branch pipes 20 and 21. It is possible to adjust, thereby adjusting the temperature of the auxiliary heat exchanger (30).

In detail, in order to prevent freezing of the outdoor unit 3, the temperature of the auxiliary heat exchanger 30 should be at least 0 ° C. or more, so the amount of refrigerant flowing into the auxiliary heat exchanger 30 should be set correspondingly. do.

However, the amount of refrigerant flowing into the auxiliary heat exchanger 30 is related to the length L of the intermediate refrigerant pipe 25. Because the pipe resistance of the first branch pipe 20 and the second branch pipe 21 is large, the length L of the intermediate refrigerant pipe 25 between the first branch pipe 20 and the second branch pipe 21. It is because the refrigerant is not flowing smoothly to the auxiliary heat exchanger (30). Therefore, the length L between the first branch pipe 20 and the second branch pipe 21 should be more than a predetermined length.

According to the experiment, the following results were obtained when the external temperature was -10 ° C and the compressor 2 hp (HP). When the length L of the intermediate refrigerant pipe 25 was 10 cm or more, 15 cm or more and 20 cm or more, respectively, the temperatures of the freezing prevention part, that is, the auxiliary heat exchanger 30 were 0 ° C, 55 ° C and 10 ° C.

Therefore, the minimum temperature of the freezing prevention part should be higher than 0 ° C. at which the water starts to freeze, so the length L of the intermediate refrigerant pipe 25 should be at least 10 cm. In addition, if the external air condition is not particularly bad, when the intermediate refrigerant pipe 25 is 15 cm or more, the temperature of the freezing prevention part becomes 5 ° C., thereby preventing freezing. However, in consideration of deviations between products, various changes in operating conditions, and safety factors, if the length L of the intermediate refrigerant pipe 25 is 20 cm or more, freezing can be prevented even under adverse conditions.

On the other hand, the experimental results were carried out under the condition of the external temperature -10 ℃, compressor 2 hp (HP), the same effect can be obtained under other conditions.

The present invention as described above ?? The effect is as follows.

First, only a part of the refrigerant is branched to the auxiliary heat exchanger, and the structure is simple, thereby reducing pipe loss and reducing heat loss, thereby improving the efficiency of the heat pump.

Second, the simple structure makes it possible to reduce costs.

Third, the refrigerant may be prevented from flowing to the auxiliary heat exchanger during the cooling operation. That is, the cooling efficiency can be improved by preventing evaporation of the refrigerant in the auxiliary heat exchanger during the cooling operation.

Claims (7)

In the heat pump comprising a compressor, a four-way valve, an outdoor unit, an expansion valve and an indoor unit sequentially connected, A first branch pipe branched from a refrigerant pipe between the expansion valve and the indoor unit, and connected to the auxiliary heat exchanger; An auxiliary heat exchanger installed in the outdoor unit to prevent freezing of the outdoor unit by heat generation of the refrigerant introduced through the first branch pipe; And a second branch pipe connected to the refrigerant pipe between the expansion valve and the indoor unit again to circulate the refrigerant in the auxiliary heat exchanger. The method of claim 1, And the auxiliary heat exchanger is installed under the heat exchanger of the outdoor unit. The method of claim 2, The diameter of the refrigerant pipe between the first branch pipe and the second branch pipe is smaller than the diameter of the first branch pipe and the second branch pipe. The method of claim 3, A length of the refrigerant pipe between the first branch pipe and the second branch pipe is longer than a predetermined length. The method of claim 4, wherein The length of the refrigerant pipe between the first branch pipe and the second branch pipe is at least 10 cm or more. The method of claim 2, At least one of the first branch pipe and the second branch pipe is provided with a check valve for preventing the back flow of the refrigerant. The method of claim 2, And a flow rate adjusting means for adjusting a flow rate of the refrigerant in the refrigerant pipe between the first branch pipe and the second branch pipe.