KR102201311B1 - Combined cooling and heating system for defrost-free heat pump and hot gas defrosting and control method thereof - Google Patents

Abstract

The present invention relates to a combined cooling and heating system. According to an embodiment of the present invention, the combined cooling and heating system comprises: a compressor for compressing a refrigerant gas; an indoor unit for heat-exchanging the refrigerant gas with indoor air; an outdoor unit for heat-exchanging the refrigerant gas with outdoor air; an accumulator for separating the refrigerant gas into a refrigerant liquid and a refrigerant gas; a first refrigerant passage which is connected from the compressor to the outdoor unit and through which a high-temperature and high-pressure gaseous refrigerant flows; a second refrigerant passage which is connected from the outdoor unit to the indoor unit and through which a low-temperature and high-pressure liquid refrigerant flows; a third refrigerant passage which is connected from the indoor unit to the compressor through the accumulator and through which a low-temperature and low-pressure gaseous refrigerant flows; and a fourth refrigerant passage which is branched from the first refrigerant passage, which has two paths connected to the indoor unit through the accumulator or directly connected to the indoor unit without passing the accumulator, and through which the high-temperature and high-pressure gaseous refrigerant flows.

Description

The combined cooling and heating system for defrost-free heat pump and hot gas defrosting and control method thereof capable of defrosting a heat pump and hot gas without defrosting;

The present invention relates to a combined cooling and heating system, and more particularly, to a combined cooling/heating system and a control method thereof capable of performing heat pump type heating without defrosting and capable of defrosting through hot gas in both single-stage and two-stage systems.

Matter exists in solid, liquid, and gaseous states, and when the state changes, it absorbs or releases heat. These properties are used for cooling or heating. That is, the air conditioner lowers the indoor temperature by rotating the circulation cycle of compressing, condensing, expanding, and exhausting the refrigerant.

In general, an air conditioner includes an outdoor unit and an indoor unit, and in the outdoor unit where condensation occurs, gas changes phase to liquid and releases heat, and in the indoor unit, the liquid phase changes to gas and absorbs surrounding heat, thereby lowering the surrounding temperature.

In addition, by operating the reverse cycle that reversed the forward cycle, the liquid phase changes to gas in the outdoor unit and absorbs heat, and the gas phase changes to liquid in the indoor unit, and releases heat to function as a heater. In addition, heating and cooling devices are also being used.

In such a cooling/heating combined device, in a regular cycle in summer (performing a cooling function), all refrigerators can exhibit suitable efficiency. However, in the case of winter (outdoor temperature -10°C), there is a rapid decrease in efficiency compared to electricity consumption.

In addition, even in a reverse cycle in winter (performing a heating function), since the outdoor unit cannot properly function as an evaporator, the high pressure and low pressure pressures are lowered, resulting in a problem that the indoor temperature cannot be increased.

Moreover, a problem due to the liquid hammer occurs in the process of defrosting and refrigerant circulation in a reverse cycle to remove frost from the evaporator.

Korean Patent Registration No. 10-1579117 (2015.12.15)

The present invention provides a separate hot gas supply flow path and efficiently configures the piping of the hot gas supply flow path and the piping of the existing flow path to enable heat pump type heating that does not require defrost, and defrosts through hot gas in both single-stage and two-stage systems. We present a system for both air conditioning and heating.

In addition, a control method of a combined cooling/heating system that can properly control such a combined cooling/heating system is proposed.

In addition, detailed objects of the present invention will be clearly understood and understood by experts or researchers in this technical field through specific contents described below.

In order to solve the above problems, the present invention is an embodiment, a compressor for compressing a refrigerant gas, an indoor unit for exchanging the refrigerant gas with indoor air, an outdoor unit for exchanging the refrigerant gas with outdoor air, and a refrigerant liquid from the refrigerant gas. A liquid heater separating the gas from the refrigerant, a first refrigerant flow channel connected from the compressor to the outdoor unit and flowing a high-temperature, high-pressure gaseous refrigerant, and piped from the outdoor unit to the indoor unit and flowing a low-temperature, high-pressure liquid refrigerant A second refrigerant flow path, a third refrigerant flow channel, which is piped from the indoor unit to the compressor through the liquid heat unit and flows a low-temperature, low-pressure gaseous refrigerant, and branched from the first refrigerant flow channel, and passes through the liquid heat unit to the indoor unit. Provided is a system for both cooling and heating including a fourth refrigerant flow path through which a high-temperature, high-pressure gaseous refrigerant flows, and consisting of two paths that are piped with or are directly piped to the indoor unit without passing through the liquid heater.

Here, an oil separator is installed in the first refrigerant flow path, the fourth refrigerant flow path is branched from the first refrigerant flow path that has passed through the oil separator, and the fourth refrigerant flow path, from the oil separator through a first control valve. In the first pipe connected to the liquid heat unit, the second pipe connected from the liquid heat unit to the indoor unit, a third pipe connected in the middle of the second pipe from the oil separator through a second isolation valve, and the first pipe And a fourth pipe connected to the second pipe through a third control valve from a point passing through the first control valve from the oil separator, and the first control valve, the second control valve, and the third control valve It may be possible to control the flow of the refrigerant by opening or blocking respectively.

In addition, a fifth refrigerant flow path branched from the third refrigerant flow path between the indoor unit and the liquid heater and connected to the third pipe between the oil separator and the second isolation valve through an isolation valve may be further included.

In addition, an isolation valve is installed in the second refrigerant flow path, and is connected to a point after joining the third pipe in the direction of the indoor unit from the second pipe from the point passing through the isolation valve in the direction of the indoor unit from the second refrigerant flow path. It may further include a connecting pipe.

On the other hand, in order to solve the above problems, the present invention is an embodiment, as a method of controlling the above-described cooling and heating combined system, the first step of controlling the cooling and heating combined system in any one of a cooling mode, a heating mode, and a defrost mode, and flows into the compressor. In the second step of setting a first temperature as a reference for determining a heating path and a second temperature as a reference for determining a defrost path with respect to the temperature of the refrigerant, when the heating mode is controlled in the second step, the first refrigerant In the third step of performing heating by supplying high-temperature gas through the flow path and the fourth refrigerant flow path and controlling the defrost mode in the second step, the high-temperature gas is supplied through the first refrigerant flow channel and the fourth refrigerant flow channel. A method for controlling a combined cooling/heating system including a fourth step of performing defrost by blocking a second refrigerant flow path is presented.

In addition, in the third step, when the temperature of the refrigerant flowing into the compressor is less than the first temperature, heating is performed through a path including a passage piped to the indoor unit through the liquid heater among the fourth refrigerant passages, and the refrigerant flowing into the compressor When the temperature of is equal to or higher than the first temperature, heating may be performed through a path that is directly piped to the indoor unit without passing through the liquid heater in the fourth refrigerant passage.

In addition, in the fourth step, when the temperature of the refrigerant flowing into the compressor is less than the second temperature, defrost is caused through a path that passes through the liquid heater of the fourth refrigerant flow path and is piped to the indoor unit or directly piped to the indoor unit without passing through the liquid heater. When the temperature of the refrigerant introduced into the compressor is equal to or higher than the second temperature, defrost may be performed through a path that is directly piped to the indoor unit without passing through the liquid heater in the fourth refrigerant passage.

According to an embodiment of the present invention, a separate hot gas supply flow path is provided, and the piping of the hot gas supply flow path and the piping of the existing flow path are efficiently configured to enable heat pump type heating that does not require defrost, and is suitable for both single-stage and two-stage systems. There is an effect of defrosting through hot gas.

Other effects of the present invention will be clearly understood and understood by experts or researchers in this technical field during the process of carrying out the present invention or through the detailed contents described below.

1 is a schematic diagram showing a simplified cooling and heating system according to an embodiment of the present invention.
Figure 2 is a flow chart showing the operation of the combined cooling and heating system according to the embodiment shown in Figure 1;
3 and 4 are schematic diagrams illustrating a flow of a refrigerant when a heating function is performed in the cooling/heating system according to the embodiment shown in FIG. 1.
5 and 6 are schematic diagrams illustrating a flow of a refrigerant when performing a defrost function in the combined cooling/heating system according to the embodiment shown in FIG. 1.
7 is a schematic diagram of a combined cooling and heating system configured to have only a defrost function as a modified example of the combined cooling and heating system according to the embodiment of FIG. 1.

The features and effects of the present invention described above will become more apparent through the following detailed description in connection with the accompanying drawings, and accordingly, those of ordinary skill in the technical field to which the present invention pertains can easily implement the technical idea of the present invention. I will be able to. In the present invention, various modifications may be made and various forms may be applied, and specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific form of disclosure, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention. The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention.

Hereinafter, a cooling/heating system according to an embodiment of the present invention will be described in detail with reference to the drawings. In the present specification, the same reference numerals are assigned to the same and similar configurations even in different embodiments, and the description is replaced with the first description.

The cooling and heating system 100 according to an embodiment of the present invention includes a compressor (1), an indoor unit (2), an outdoor unit (3), a liquid heat unit (4), a first refrigerant passage (5), and a second refrigerant passage (6). , It includes a third refrigerant flow path (7) and a fourth refrigerant flow path (8).

The compressor 1 compresses the refrigerant gas, and the outdoor unit 3 heats the compressed refrigerant gas with outdoor air. Meanwhile, the indoor unit 2 performs a cooling or heating function by exchanging refrigerant gas with indoor air. Here, when the refrigerant gas performs a heating function (or a defrost function), a part of the refrigerant gas may be in a liquid state. The liquid heater 4 separates the liquid refrigerant from the refrigerant gas.

The first refrigerant passage 5 is connected from the compressor 1 to the outdoor unit 3, and a high-temperature, high-pressure gaseous refrigerant flows, and the second refrigerant passage 6 is piped from the outdoor unit 3 to the indoor unit 2 And a low temperature, high pressure liquid refrigerant flows. The third refrigerant flow path 7 is piped from the indoor unit 2 through the liquid heater 4 to the compressor 1, and a low temperature and low pressure gaseous refrigerant flows.

Meanwhile, the fourth refrigerant flow path 8 is branched from the first refrigerant flow path 5 and is piped to the indoor unit 2 through the liquid heater 4 or directly to the indoor unit 2 without passing through the liquid heater 4. It consists of two paths to be piped, and a high-temperature, high-pressure gaseous refrigerant flows.

The cooling/heating system 100 configured as described above enables heat pump-type heating that does not require defrost by separately supplying hot gas through the fourth refrigerant flow path 8, and defrosts through hot gas in both single-stage and two-stage systems are possible. .

Hereinafter, the configuration of each unit will be described in detail with reference to the drawings.

1 is a schematic diagram showing a simplified cooling and heating system according to an embodiment of the present invention.

Compressor (1) is a component that performs a function of compressing refrigerant gas, and is composed of various forms capable of compressing gases such as reciprocating pistons, screws, scrolls, etc., by introducing refrigerant gas from the suction stroke and flowing from the compression stroke. Compressed refrigerant gas. The compressor 1 may employ both a single-stage compressor 1 and a two-stage compressor 1, and when the two-stage compressor 1 is employed, an economizer 62 may be installed to increase efficiency.

The indoor unit 2 performs a cooling or heating function by exchanging refrigerant gas with indoor air. In the present invention, the indoor unit performs a cooling function by evaporating the refrigerant liquid through the second refrigerant passage 6 when performing the cooling function, and condenses the refrigerant gas through the fourth refrigerant oil passage 8 when performing the heating function. To perform the heating function.

The outdoor unit 3 heat-exchanges the compressed refrigerant gas with outdoor air. In the present invention, a low-temperature, low-pressure refrigerant liquid flows through the outdoor unit 3 in both the cooling function and the heating function. However, when performing the cooling function, most of the refrigerant passes through the second refrigerant passage (6), so the amount of refrigerant passing through the outdoor unit (3) is large, and when performing the heating function, most of the refrigerant passes through the fourth refrigerant passage (8). ), so the amount of refrigerant passing through the outdoor unit 3 is small.

The liquid heater 4 separates the refrigerant liquid and the refrigerant gas. The refrigerant gas separated here is supplied to the compressor 1 again. Meanwhile, according to an embodiment of the present invention, since the high-temperature and high-pressure refrigerant gas from the compressor 1 can be introduced into the liquid heater 4 through the fourth refrigerant flow path 8, the liquid heater 4 is heat-exchanged with the refrigerant gas. Evaporation of the refrigerant liquid may occur within.

Hereinafter, each flow path in the configuration of the present invention will be described in detail. Basically, the flow path includes the first refrigerant flow path 5, the second refrigerant flow path 6, the third refrigerant flow path 7 and the fourth refrigerant flow path 8, and additionally includes a fifth refrigerant flow path 9. I can.

Meanwhile, a plurality of components used in the conventional cooling and heating system 100 may be installed in each flow path. The cooling/heating system 100 according to an embodiment of the present invention may include an oil separator 51, a receiver 61, and an economizer 62. In addition, various check valves and ball valves for controlling the flow of refrigerant may be installed. The check valve is a device that prevents reverse flow of the refrigerant, and the ball valve functions to regulate the refrigerant flowing through the pipe.

The first refrigerant flow path 5 is a flow path connected from the compressor 1 to the outdoor unit 3 and through which a high-temperature, high-pressure gaseous refrigerant flows. Here, an oil separator 51 is installed in the first refrigerant passage 5 and a fourth refrigerant passage 8 to be described later may branch from the first refrigerant passage 5 that has passed through the oil separator 51.

Referring to the drawings, the oil separator 51 is disposed between the compressor 1 and the outdoor unit 3. The lubricating oil of the compressor 1 may be mixed with the refrigerant while passing through the compressor 1, and the oil separator 51 separates the lubricating oil of the compressor 1 and the refrigerant in the compressor 1. The separated lubricating oil is supplied to the compressor 1 and recycled.

The second refrigerant flow path 6 is a flow path that is piped from the outdoor unit 3 to the indoor unit 2 and through which a low-temperature, high-pressure liquid refrigerant flows. Here, a receiver 61, an economizer 62, a filter dryer (not shown), and various valves may be installed in the second refrigerant passage 6.

The receiver 61 stores a refrigerant liquid. The receiver 61 absorbs a change in the amount of refrigerant according to a change in a load in the indoor unit to facilitate operation. That is, the receiver 61 temporarily stores the liquid condensed in the outdoor unit 3 and sends only the amount of refrigerant liquid required in the indoor unit 2 to the expansion valve 30, thereby reducing the risk of cycle. do. The receiver 61 is preferably filled with a refrigerant liquid of 75% or less.

In the present invention, the reverse cycle through the conventional four-way valve is not performed, and only the forward cycle is performed. However, when performing the cooling function, a large amount of refrigerant flows into the outdoor unit 3, whereas when performing the heating function, only a small amount of refrigerant flows into the outdoor unit 3, and other refrigerants are used in the fourth refrigerant flow path ( By flowing through 8), it performs a heating function using hot gas. The receiver 61 absorbs a change in the amount of refrigerant in both cooling and heating functions to facilitate operation.

In addition, the economizer 62 may perform a function of performing high-efficiency two-stage compression in cooperation with a two-stage compressor. The economizer 62 may be omitted when a single stage compressor is employed as the compressor 1.

Meanwhile, a filter dryer (not shown) may be disposed between the receiver 61 and the economizer 62 to perform a function of removing moisture and impurities contained in the refrigerant.

The third refrigerant flow path 7 is piped from the indoor unit 2 through the liquid heater 4 to the compressor 1, and a low temperature and low pressure gaseous refrigerant flows.

In the present embodiment, in the indoor unit 2, the refrigerant gas is condensed to become a low-temperature and low-pressure gas state. In the case of performing the defrosting function, the gas is mixed with some liquid. The refrigerant in this state is introduced into the liquid heater 4.

As described above, the liquid heater 4 separates the refrigerant liquid from the refrigerant gas, and the separated refrigerant gas is supplied to the compressor 1 again. Meanwhile, the refrigerant gas supplied to the compressor (1) becomes a high-temperature and high-pressure refrigerant gas by the compressor (1), and the high-temperature and high-pressure refrigerant gas can flow back into the liquid heater (4) through the fourth refrigerant passage (8). In this case, heat exchange with the refrigerant liquid is performed so that it is possible to convert the refrigerant liquid into a refrigerant gas.

The fourth refrigerant passage (8) is branched from the first refrigerant passage (5), and is piped to the indoor unit (2) through the liquid heater (4) or directly to the indoor unit (2) without passing through the liquid heater (4). It consists of two paths, and a high temperature and high pressure gaseous refrigerant flows.

Meanwhile, as described above, an oil separator 51 may be installed in the first refrigerant passage 5, in which case the fourth refrigerant passage 8 branches from the first refrigerant passage 5 passing through the oil separator 51. , The first pipe 81, the second pipe 82, the third pipe 83 and the fourth pipe 84 may be formed.

Here, the first pipe 81 is connected from the oil separator 51 to the liquid heater 4 through the first shut-off valve 85, and the second pipe 82 is from the liquid heater 4 to the indoor unit 2 The third pipe 83 is connected to the middle of the second pipe 82 from the oil separator 51 through the second shut-off valve 86. The third pipe 83 may be used as a bypass path through which the refrigerant flows to the indoor unit without passing through the liquid heat unit.

According to this configuration, the first isolating valve 85 is blocked and the second isolating valve 86 is opened so that the refrigerant moves to the indoor unit 2 through the third pipe 83 and the second pipe 82, or It is possible to select the movement of the refrigerant to the indoor unit 2 through the first pipe 81 and the second pipe 82 by blocking the shut-off valve 86 and opening the first shut-off valve 85. Meanwhile, opening both the first and second control valves 85 and 86 to allow the refrigerant to move to the indoor unit through the first pipe 81, the second pipe 82, and the third pipe 83 It is possible.

The refrigerant moving through the third pipe 83 and the second pipe 82 is a high-temperature, high-pressure gaseous refrigerant that is directly moved from the compressor 1 to the indoor unit 2 without passing through the liquid heater 4 The refrigerant moving through the pipe 81 and the second pipe 82 is also a high-temperature and high-pressure gaseous refrigerant and moves from the compressor 1 to the indoor unit 2 through the liquid heater 4.

Here, a fourth pipe 84 connecting the first pipe 81 and the second pipe 82 may be further provided. The fourth pipe 84 is provided with a third intermittent valve 87, and according to the operation of the third intermittent valve, the refrigerant moving through the first pipe 81 does not pass through the liquid heater 4 and the second pipe 82 ) Can be moved.

Specifically, the fourth pipe 84 is branched from the first pipe 81, and the third isolating valve 87 from the point passing the first isolation valve 85 from the oil separator 51 in the first pipe 81 It is connected to the second pipe 82 through. The fourth pipe 84 may be used as another bypass path through which the refrigerant flows to the indoor unit without passing through the liquid heater 4.

Meanwhile, of the third refrigerant passage 7, a fifth refrigerant passage branched from the passage between the indoor unit 2 and the liquid heater 4 and connected to one end of the second shut-off valve 86 through the fourth shut-off valve 91 (9) may be further included. Referring to the drawings, the fifth refrigerant flow path 9 is connected to a portion of the third pipe 83 between the second isolation valve 86 and the oil separator 51.

For rapid heating or defrosting, it is necessary to increase the amount of gaseous refrigerant transferred from the liquid heater 4 to the compressor 1. During the initial defrosting or heating, the temperature of the refrigerant flowing from the indoor unit 2 to the liquid heater 4 is low, and thus there is a possibility that a liquid refrigerant may be included. Accordingly, the high-temperature and high-pressure gaseous refrigerant discharged from the oil separator 51 through the compressor 1 is introduced into the third refrigerant flow path 7 to heat exchange with the refrigerant flowing into the liquid heater 4. Accordingly, the temperature of the refrigerant flowing into the liquid heater 4 can be increased, and the liquid refrigerant can be minimized.

Meanwhile, a connection pipe 10 connecting the second refrigerant passage 6 and the fourth refrigerant passage 8 at a predetermined point may be further installed. Specifically, the fifth isolating valve 20 is installed in the second refrigerant passage 6, and the second pipe and the point passing through the fifth isolating valve 20 in the direction of the indoor unit 2 in the second refrigerant passage 6 A point after joining the third pipe 83 in the direction of the indoor unit 2 at (82) may be connected through the connection pipe (10). Meanwhile, the connecting pipe can be configured in plural.

In this configuration, when the fifth intermittent valve 20 is blocked, the liquid refrigerant moving to the indoor unit 2 through the second refrigerant flow path is blocked, and the high temperature that moves to the indoor unit 2 through the fourth refrigerant flow channel 8 Only high-pressure gaseous refrigerant can flow into the indoor unit 2. This function is particularly useful for defrosting in which a lot of heat needs to be supplied in a short time, and accordingly, defrosting of the indoor unit 2 can be performed quickly.

As described above, the cooling/heating system 100 according to an embodiment of the present invention may supply hot gas to the indoor unit 2 by providing a separate hot gas supply channel. Accordingly, it is easy to defrost the indoor unit 2 when performing the cooling function. In addition, since a high-temperature refrigerant may be introduced into the outdoor unit 3 when performing the heating function, a heat pump type heating without defrosting is possible.

In addition, since it is possible to supply hot gas without a four-way valve or reverse cycle by efficiently linking the piping of the hot gas supply flow path and the piping of the existing flow path, it is possible to supply hot gas to both single-stage systems and two-stage systems that are difficult to operate reverse cycles Defrost of the indoor unit is possible through the effect.

Hereinafter, a control method of a cooling/heating system according to an embodiment of the present invention will be described in detail with reference to the drawings.

Figure 2 is a flow chart showing the operation of the combined cooling and heating system according to an embodiment of the present invention, Figures 3 and 4 are schematic diagrams showing the flow of the refrigerant when the combined cooling and heating system performs a heating function, and 6 is a schematic diagram illustrating a flow of a refrigerant when the combined cooling/heating system performs a defrost function.

In the case of cooling, after compressing in the compressor (1) to separate the lubricant and refrigerant gas in the oil separator (51), condensate in the outdoor unit (2) and store the liquid in the receiver (61), the ball valve (50) And the refrigerant through the sixth intermittent valve 40 is expanded in the expansion valve 30, vaporized through heat exchange with air in the indoor unit 3, and sucked back into the compressor 1, thereby operating in a forward cycle.

On the other hand, in the case of heating and defrosting, as in the case of cooling, a forward cycle is applied, but in addition, the high-temperature and high-pressure refrigerant gas is directly supplied to the indoor unit 2 through the fourth refrigerant passage 8.

Based on this principle, the control method of the cooling/heating system 100 according to an embodiment of the present invention includes a first step (S10) of controlling a mode, a second step of classifying a temperature (S20), and a first step of performing heating. It includes a third step (S30) and a fourth step (S40) of performing defrost.

Each of these steps may be performed through a control unit (not shown) provided in the combined cooling/heating system 100, and each step may be selectively and independently performed.

First, in the first step (S10), the cooling/heating system is controlled in one of a cooling mode, a heating mode, and a defrost mode.

Next, in the second step (S20), in the heating mode or the defrost mode, the temperature of the refrigerant flowing into the compressor 1 is used as a reference for determining a heating path and a first temperature as a reference for determining the defrost path. 2 Set the temperature. The first temperature is -10 degrees, for example, and the second temperature is -20 degrees, for example. The path of the refrigerant may be controlled so that heating or defrosting is efficiently performed according to the temperature standard.

Next, in the third step (S30), when the heating mode is controlled in the first step (S10), heating can be performed by supplying a high-temperature gas through the first refrigerant passage (5) and the fourth refrigerant passage (8). have.

Specifically, in the third step (S30), the fourth refrigerant passage 8 passes through the liquid heater 4 and is piped to the indoor unit 2 when the temperature is less than the first temperature according to the temperature range determined in the second step. Heating may be performed through (see FIG. 3).

At this time, the first isolating valve 85 is in an open state and the second isolating valve 86 may be selectively opened. The temperature of the refrigerant can be measured through a temperature sensor (not shown) installed in the third refrigerant passage 7.

Meanwhile, when the second isolating valve 86 is opened, the high temperature and high pressure gaseous refrigerant discharged from the oil separator 51 through the compressor 1 by opening the fourth isolating valve 91 is transferred to the third refrigerant passage 7 ) To heat exchange with the refrigerant flowing into the liquid heater 4. Accordingly, by increasing the temperature of the refrigerant flowing into the compressor, it may be possible to quickly heat the initial stage.

On the other hand, when the temperature of the refrigerant reaches the first temperature or higher, the initial heating is deemed to have ended, and the third intermittent valve 87 is opened to allow the refrigerant to move directly to the indoor unit 2 without passing through the liquid heater 4 to accelerate heating. do. On the other hand, at this time, it is possible to prevent a sudden increase in temperature and pressure by blocking the second intermittent valve 86 (see FIG. 4). Accordingly, precise heating control is possible according to the temperature of the refrigerant flowing into the compressor 1.

As described above, since the high-temperature refrigerant discharged from the compressor flows into the outdoor unit at this time, frost does not occur in the outdoor unit in winter. Accordingly, defrosting of the outdoor unit is not required.

Meanwhile, in the fourth step (S40), when the defrost mode is controlled in the first step (S10), hot gas is supplied through the first refrigerant passage (5) and the fourth refrigerant passage (8), while the second refrigerant passage ( Defrost can be performed by blocking 6).

In the case of the defrost mode, the control method is generally the same as in the case of the heating mode. When the temperature of the refrigerant is less than the second temperature, defrosting is performed through two paths that are piped to the indoor unit (2) through the liquid heater (4) or directly to the indoor unit (2) without passing through the liquid heater (4). do.

However, since the second refrigerant passage 6 is blocked, there is no refrigerant flowing into the indoor unit 2 from the second refrigerant passage 6 (see FIG. 5). In addition, the first and second control valves 85, 86, and the fourth control valve 91 are all open. This is to quickly increase the temperature of the refrigerant flowing into the compressor because the temperature of the indoor unit is lower than that of heating in the case of defrosting.

On the other hand, when the temperature of the refrigerant reaches the second temperature or higher, it is assumed that the initial defrost is over, and the third intermittent valve 87 is opened so that the refrigerant can move to the indoor unit 2 without passing through the liquid heater 4, thereby accelerating the defrost .

Meanwhile, at this time, the auxiliary expansion valves 63 and 64 are selectively operated so that the low-temperature and high-pressure refrigerant liquid in the second refrigerant passage 6 is transferred to the third refrigerant passage 7 or the second pipe 82 of the fourth refrigerant passage 8 ) Can be introduced in an expanded state, and the second and fourth control valves 86 and 91 can be blocked to prevent a sudden increase in temperature and pressure (see FIG. 6).

By circulating such a cycle, precise defrost control is possible according to the temperature of the refrigerant flowing into the compressor 1. For reference, the defrost time is about 5 minutes at -20 degrees and above, and about 20 minutes at -40 degrees, and it is possible to defrost at a temperature of about 65 to 80 degrees. Accordingly, it is possible to minimize the temperature change of the indoor unit.

On the other hand, when the heating function is excluded and only the defrost function is to be used, the second pipe 82 of the fourth refrigerant passage 8 is not connected to the indoor unit 2, and the second refrigerant passage 6 as shown in FIG. ) Can be connected to a point through the fifth intermittent valve 20 in the direction of the indoor unit. Accordingly, when the fifth intermittent valve 20 is shut off, a part of the second refrigerant flow path 6 can be used as a flow path through which the high temperature and high pressure refrigerant gas flows. Accordingly, economic feasibility can be secured.

As described above, the cooling/heating system and a control method thereof according to an embodiment of the present invention are not limited to the configuration and method of the above-described embodiments, but the embodiments are All or some may be selectively combined and configured.

In the detailed description of the present invention described above, it has been described with reference to preferred embodiments of the present invention, but those skilled in the art or those of ordinary skill in the relevant technical field, the spirit of the present invention described in the claims to be described later. And it will be appreciated that various modifications and changes can be made to the present invention within a range not departing from the technical field.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Indoor unit 3 Outdoor unit 4 Liquid heat unit
5: first refrigerant flow path 51: oil separator
6: second refrigerant flow path 61: receiver 62: economizer 63, 64: auxiliary expansion valve
7: 3rd refrigerant flow path
8: 4th refrigerant flow path
81: first pipe 82: second pipe 83: third pipe 84: fourth pipe
85: first shut-off valve 86: second shut-off valve 87: third shut-off valve
9: fifth refrigerant flow path 91: fourth intermittent valve
10: connection pipe 20: 5th intermittent valve
30: expansion valve 40: 6th speed valve 50: ball valve
100: dual cooling and heating system

Claims (7)

Compressor to compress refrigerant gas,
An indoor unit that heat-exchanges the refrigerant gas with indoor air,
An outdoor unit for exchanging the refrigerant gas with outdoor air,
A liquid heater for separating a refrigerant liquid and a refrigerant gas from the refrigerant gas,
A first refrigerant flow path connected from the compressor to the outdoor unit and through which a high-temperature, high-pressure gaseous refrigerant flows,
A second refrigerant flow passage piped from the outdoor unit to the indoor unit and through which a low-temperature, high-pressure liquid refrigerant flows,
A third refrigerant passage piped from the indoor unit to the compressor through the liquid heat unit and through which a low-temperature, low-pressure gaseous refrigerant flows, and
A refrigerant in a gaseous state of high temperature and high pressure that is branched from the first refrigerant flow path and is piped to the indoor unit through the liquid heat unit or directly piped to the indoor unit without passing through the liquid heat unit. 4th refrigerant flow path
Including,
An oil separator is installed in the first refrigerant passage, and the fourth refrigerant passage is branched from the first refrigerant passage passing through the oil separator,
The fourth refrigerant flow path,
A first pipe connected from the oil separator to the liquid heater through a first intermittent valve,
A second pipe connected from the liquid heat to the indoor unit,
A third pipe connected in the middle of the second pipe from the oil separator through a second isolation valve, and
A fourth pipe connected to the second pipe through a third isolation valve from a point in the first pipe passing the first isolation valve from the oil separator
Including,
A cooling/heating system capable of controlling the flow of refrigerant by opening or shutting off the first, second and third control valves, respectively. delete The method of claim 1,
A cooling/heating combined system further comprising a fifth refrigerant flow path branched from the third refrigerant flow path between the indoor unit and the liquid heat unit and connected to the third pipe between the oil separator and the second isolation valve through an isolation valve. The method of claim 1,
An isolation valve is installed in the second refrigerant flow path,
A cooling/heating combined system further comprising a connection pipe connected to a point after the second refrigerant passage passes through the intermittent valve in the direction of the indoor unit and after joining the third pipe in the direction of the indoor unit from the second pipe. As a method of controlling the combined cooling and heating system of any one of claims 1, 3 to 4,
A first step of controlling the cooling/heating system in any one of a cooling mode, a heating mode, and a defrost mode,
A second step of setting a first temperature serving as a reference for determining a heating path and a second temperature serving as a reference for determining a defrost path with respect to the temperature of the refrigerant flowing into the compressor,
In the case of controlling the heating mode in the second step, a third step of performing heating by supplying a high-temperature gas through the first refrigerant passage and the fourth refrigerant passage, and
In the case of controlling the defrost mode in the second step, a fourth step of supplying hot gas through the first and fourth refrigerant passages and blocking the second refrigerant passage to perform defrost
Cooling and heating combined system control method comprising a. The method of claim 5,
In the third step,
When the temperature of the refrigerant flowing into the compressor is less than the first temperature, heating is performed through a path including a flow path piped to the indoor unit through the liquid heater among the fourth refrigerant flow channels,
When the temperature of the refrigerant flowing into the compressor is higher than the first temperature, heating is performed through a path directly piped to the indoor unit without passing through the liquid heater in the fourth refrigerant flow path.
Control method for both heating and cooling systems. The method of claim 5,
In the fourth step,
When the temperature of the refrigerant flowing into the compressor is less than the second temperature, defrosting is performed through a path that passes through the liquid heater of the fourth refrigerant flow path and is piped to the indoor unit or directly piped to the indoor unit without passing through the liquid heater,
When the temperature of the refrigerant flowing into the compressor is higher than the second temperature, defrosting is performed through the path directly piped to the indoor unit without passing through the liquid heater in the fourth refrigerant flow path.
Control method for both heating and cooling systems.

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