KR20110062457A - Heat pump system - Google Patents

Abstract

PURPOSE: A heat pump system is provided to inject refrigerants by setting the target opening degree of an injection valve depending on the change of sensed operation variable values. CONSTITUTION: A heat pump system comprises a main circuit, a hot water supply unit(300), and a controller. The main circuit comprises a compressor(110) with multiple compression chambers, a condenser(120), an expansion unit, an evaporator(130), and an injection valve(153). The condenser condenses compressed refrigerants. The expansion unit throttles the condensed refrigerants. The evaporator evaporates the expanded refrigerants. The injection valve throttles the refrigerants flowing into one compression chamber. The hot water supply unit uses water heated in the condenser. The controller senses the operation variable values in real time and sets the target opening degree of the injection valve depending on the change of the operation variable values.

Description

Heat pump system

The present invention relates to a heat pump system, and more particularly, to a heat pump system in which heating is improved by injection of a refrigerant in consideration of both an outdoor temperature and a frequency of a compressor.

In general, a heat pump is a device for cooling or heating an indoor space by performing a process of compressing, condensing, expanding, and evaporating a refrigerant.

The heat pump is classified into a conventional air conditioner in which one indoor unit is connected to an outdoor unit, and a multi air conditioner in which a plurality of indoor units are connected to the outdoor unit. The heat pump further includes a hot water supply unit for supplying hot water and a heating unit for supplying and heating the warm water.

The heat pump includes a compressor, a condenser, an expansion valve, and an evaporator. The refrigerant discharged from the compressor is condensed in the condenser and then expanded in the expansion valve. The expanded refrigerant is evaporated in the evaporator and then sucked into the compressor.

However, the heat pump according to the prior art may not fully exhibit the cooling and heating capability when the cooling and heating load fluctuates, such as the outdoor temperature. For example, in a cold region, there is a problem that the heating performance is very low. When replacing a large capacity heat pump or installing a new heat pump additionally, there is a problem in that the installation cost is high, and the installation space must be secured.

It is an object of the present invention to provide a heat pump system capable of improving heating performance.

The heat pump system according to the present invention includes a compressor having a plurality of compression chambers, a condenser for condensing the refrigerant passing through the compressor, an expansion device for condensing the refrigerant passing through the condenser, and a refrigerant expanded in the expansion device. A main circuit including an evaporator to which evaporates and an injection valve branched between the condenser and the evaporator to cool refrigerant introduced into one of the plurality of compression chambers; A hot water supply unit that uses hot water heated by the condenser for hot water supply; And a controller configured to detect a driving variable value of a plurality of driving variables in real time and to set a target opening degree of the injection valve according to the detected change of the operating variable value.

In the present invention, the operating variables may include the frequency of the compressor and the outdoor temperature of the main circuit.

In the present invention, the control unit may pre-store the setting values corresponding to the detected operating variable value.

In the present invention, the respective setting values for the plurality of operating variables may independently change the target opening degree of the injection valve.

In the present invention, the controller may set the target opening degree of the injection valve based on a linear combination of the set values.

In the present invention, the control unit may open the injection valve when the outdoor temperature of the main circuit is less than a predetermined set temperature.

In the present invention, the control unit may open the injection valve according to the frequency of the compressor when there is a required load of the hot water supply unit, if the outdoor temperature of the main circuit is above a predetermined set temperature.

In the present invention, the control unit may control so that the target opening degree of the injection valve is proportional to the frequency of the compressor.

In the present invention, the expansion device is a first expansion device for throttling the refrigerant passing through the condenser, and the first expansion device and the evaporator disposed between the first expansion device is a first It may include two expansion devices.

In the present invention, it may further include a heating unit for using the water heated in the condenser for heating.

The heat pump system according to the present invention includes a control unit for detecting a plurality of operating variable values in real time and setting a target opening degree of the injection valve according to a change of the detected operating variable values, thereby providing an appropriate flow rate according to the operating state. Since the refrigerant can be injected, performance can be ensured.

In addition, since the target opening degree of the injection valve is set not only according to the outdoor temperature but also the frequency of the compressor, the refrigerant can be properly injected not only in the low temperature region where the outdoor temperature is lower than the preset temperature but also in the temperature region where the load is required. Therefore, performance can be improved.

In addition, since the target opening degree of the injection valve is set in proportion to the frequency of the compressor, the phenomenon in which the injection valve is excessively opened during low frequency driving of the compressor can be prevented even when frequent on / off of the compressor occurs.

In addition, when there is a hot water load from the hot water supply unit, it is possible to promptly determine whether or not the injection of the coolant is requested, and inject the coolant to appropriately cope with the hot water load due to the secured flow rate of the coolant.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a view showing the configuration of a heat pump system according to an embodiment of the present invention.

Referring to FIG. 1, a heat pump system according to an exemplary embodiment of the present invention includes a main circuit 100 including a compressor 110, a condenser, an expansion device, and an evaporator, and a hot water supply using hot water heated by the condenser. Unit 300.

Here, the main circuit 100 refers to a refrigerant cycle device.

The compressor 110 may include a plurality of compression chambers, a rotary compressor may be used, and a scroll compressor may be used. Hereinafter, it will be described that a rotary compressor is used in the present embodiment.

The compressor 110 includes a first compression unit 114 through which the refrigerant passing through the evaporator is introduced and compressed, a refrigerant passing through the first compression unit 114, a first expansion valve, and a second expansion valve to be described later. And a second compression unit 116 into which refrigerant mixed with the refrigerant injected and branched therebetween is introduced and compressed.

In the condenser, the refrigerant compressed by the compressor 110 flows in and condenses. During the heating operation, the indoor heat exchanger 120 installed in the room serves as a condenser.

The expansion device includes a first expansion valve 141 through which the refrigerant passing through the condenser is throttled, and a refrigerant passing through the first expansion valve 141 between the first expansion valve 141 and the evaporator is throttled. A second expansion valve 142 may be included.

The evaporator is a device in which the refrigerant throttled by the second expansion valve 142 is introduced and evaporated. During the heating operation, the outdoor heat exchanger 130 installed outdoors serves as an evaporator.

The compressor 110 has a first inlet 111 connected to a sixth connection pipe 176 to be described later, and a second inlet so that refrigerant injected by being connected to the injection pipe 151 to be described later flows into the second compression unit. 112 is formed.

The four-way valve 160 is a flow path switching valve for switching the flow of the refrigerant during heating and cooling. The four-way valve 160 guides the refrigerant compressed by the compressor 110 to the outdoor heat exchanger 130 when cooled, and guides the indoor heat exchanger 120 when heated.

One side of the four-way valve 160 is connected to the compressor 110 and the first connection pipe 171. The other side of the four-way valve 160 is connected to the indoor heat exchanger 120 and the second connection pipe 172.

The indoor heat exchanger 120 and the injection heat exchanger 150 described later are connected to a third connection pipe 173, and the first expansion valve 141 is disposed on the third connection pipe 173.

The injection heat exchanger 150 and the evaporator are connected to the fourth connection pipe 174, and the second expansion valve 142 is disposed on the fourth connection pipe 174.

One side of the four-way valve 160 is connected to the compressor 110 and the first connection pipe 171. The other side of the four-way valve 160 is connected to the indoor heat exchanger 120 and the second connection pipe 172.

The indoor heat exchanger 120 and the injection heat exchanger 150 are connected to a third connection pipe 173, and the first expansion valve 141 is disposed on the third connection pipe 173.

The injection heat exchanger 150 and the evaporator are connected to the fourth connection pipe 174, and the second expansion valve 142 is disposed on the fourth connection pipe 174.

The injection pipe 151 which guides the refrigerant from the first expansion valve 141 through the injection heat exchanger 150 and then guides the compressor 110 to the third connection pipe 173 is connected.

The four-way valve 160 is connected to the outdoor heat exchanger 130 and the fifth connection pipe 175. In addition, the four-way valve 160 is connected to the inlet of the compressor 110 and the sixth connecting pipe 176.

The injection heat exchanger 150 heats the refrigerant flowing out of the first expansion valve 141 to the second expansion valve 142 and the refrigerant flowing through the injection pipe 151 during the heating operation.

The injection pipe 151 is provided with an injection valve 153 for controlling the flow rate of the refrigerant to be injected. By controlling the opening degree of the injection valve 153, the amount of refrigerant injected and the refrigerant pressure may be controlled.

The injection heat exchanger 150 may be formed in a double tube structure including a refrigerant pipe in which the injected refrigerant flows and a refrigerant pipe flowing in the evaporator, or may be formed as a plate heat exchanger.

In addition, the present invention is not limited thereto. Instead of the injection heat exchanger 150, a phase separator for separating the refrigerant passing through the first expansion valve 141 into a gaseous refrigerant and a liquid refrigerant may be used. .

On the other hand, the hot water supply unit 300 is a device for supplying hot water required for washing, bathing or washing dishes.

The hot water supply unit 300 includes a hot water tank 310 in which water is contained, and an auxiliary heater 312 for hot water installed in the hot water tank 310.

A cold water inlet 314 is connected to the hot water tank 310 to supply cold water to the hot water tank 310, and a hot water outlet 316 to which hot water heated in the hot water tank 310 is discharged is connected. do.

The hot water discharge unit 316 may be connected to a hot water discharge mechanism 318 such as a shower. A cold water inlet 320 may be connected to the hot water outlet 316 so that cold water may be discharged to the hot water outlet 318.

The hot water supply unit 300 is connected to the indoor heat exchanger 120 that serves as a condenser during the heating operation by the hot water circulation passage 301.

The hot water circulation passage 301 includes an indoor unit pipe 302 located inside the main circuit 100, a hot water supply pipe 303 disposed in the hot water supply unit 300, the indoor unit pipe 302, and the hot water supply. It comprises a connection pipe 304 for connecting the pipe 303.

The connection pipe 304 may be provided with a hot water control valve 306 to regulate the supply of hot water.

2 is a block diagram showing a control flow of a heat pump system according to an embodiment of the present invention.

Referring to FIG. 2, the heat pump system may include a control unit configured to detect operating variable values of a plurality of operating variables in real time and to set a target opening degree of the injection valve 153 according to a change in the detected operating variable value ( 200).

The plurality of operating variables may include an outdoor temperature of the main circuit 100 and a frequency of the compressor 110.

Setting values corresponding to the sensed driving variable values may be predetermined and stored in the form of a table in the controller 200.

The set values may independently change the target opening degree of the injection valve 153.

The controller 200 may set a target opening degree of the injection valve 153 based on a linear combination of the set values.

The method for obtaining the target opening degree of the injection valve 153 is as follows.

Target opening = C1 * F (outdoor temperature) + C2 * F (compressor frequency) + C3

Here, F (outdoor temperature) is a preset value according to the sensed outdoor temperature, F (frequency of the compressor) is a preset value according to the detected frequency of the compressor. C1 and C2 are proportional constants, and C3 is a constant including 0 and can be preset by operating conditions or external environment.

However, the present invention is not limited thereto, and the set value may of course use the detected value as it is.

3 is a view illustrating a flow of a refrigerant during hot water supply operation of the heat pump system shown in FIG. 1.

Referring to FIG. 3, if there is a hot water supply request, the main circuit 100 performs a heating operation.

The high temperature and high pressure refrigerant discharged from the compressor 110 flows into the indoor heat exchanger 120 through the four-way valve 160. At this time, the indoor heat exchanger 120 serves as a condenser.

The refrigerant introduced into the indoor heat exchanger 120 is condensed by performing heat exchange with water flowing through the indoor unit pipe 302. The condensed refrigerant is throttled by the first expansion valve 141.

At this time, when there is a request for operation of gas injection, the control unit 2000 opens the injection valve 153.

When the injection valve 153 is opened, some of the refrigerant flowing through the third connection pipe 173 is bypassed to the injection pipe 151. The refrigerant bypassed from the third connection pipe 173 to the injection pipe 151 is throttled by the injection valve 153.

Since the refrigerant throttled by the injection valve 153 is lowered in temperature and pressure, the refrigerant throttled is relatively lower than the refrigerant flowing into the injection heat exchanger 150 from the third connection pipe 173.

Therefore, in the injection heat exchanger 150, heat exchange between the refrigerant introduced through the injection pipe 151 and the refrigerant introduced through the third connection pipe 173 is performed. The refrigerant flowing through the injection pipe 151 in the injection heat exchanger 150 absorbs heat, and the refrigerant discharged to the second expansion valve 142 is deprived of heat.

The refrigerant deprived of heat from the injection heat exchanger 150 is throttled by the second expansion valve 142 and then flows into the outdoor heat exchanger 130.

The refrigerant introduced into the outdoor heat exchanger 130 is evaporated by heat exchange with external air, and the evaporated refrigerant flows into the first inlet 111 of the compressor 110. The refrigerant introduced into the first inlet 111 is compressed in the first compression unit of the compressor 110.

Meanwhile, the refrigerant absorbing heat in the injection heat exchanger 150 may be a two-phase refrigerant in which at least a portion of the refrigerant is evaporated, mixed with a liquid phase and a gaseous phase, or a refrigerant in a superheated vapor state. The proportion of the liquid refrigerant in the refrigerant absorbing heat in the injection heat exchanger 150 may be adjusted according to the characteristics of the injection heat exchanger 190 or the opening degree of the injection valve 153.

The refrigerant on the injection pipe 151 discharged from the injection heat exchanger 150 flows into the second inlet 112 of the compressor 110. The refrigerant introduced into the second inlet 112 is mixed with the refrigerant compressed in the first compression unit and compressed in the second compression unit.

The refrigerant compressed by the second compression unit is circulated to the four-way valve 160 again.

Meanwhile, the indoor heat exchanger 120 serves as a condenser, and water in the indoor unit pipe 302 receives heat from the indoor heat exchanger 120 serving as a condenser.

The hot water on the indoor unit pipe 302, which absorbs heat from the indoor heat exchanger 120, passes through the connection pipe 304 and the hot water supply pipe 303 in order to transfer heat to the hot water tank 310.

Therefore, the water inside the hot water tank 310 is heated, so that hot water may be supplied to the user through the hot water outlet 316.

A method of controlling the opening degree of the injection valve in the heat pump system configured as described above is as follows.

When the outdoor temperature of the main circuit 100 is lower than a predetermined set temperature during the heating operation, the controller 200 determines that there is an injection request of the refrigerant, and opens the injection valve 153.

As described above, the controller 200 sets the target opening degree of the injection valve 153 by the following equation. Since the following equation has been described in detail above, the detailed description of the equation is omitted.

Target opening = C1 * F (outdoor temperature) + C2 * F (compressor frequency) + C3

That is, the injection valve 153 is opened by setting a target opening degree of the injection valve 153 in consideration of the outdoor temperature and the frequency of the compressor.

At this time, when the main circuit 100 reaches the heating target temperature, the compressor 110 is repeated (ON) and off (OFF). That is, when the main circuit reaches the heating target temperature, the compressor 110 is turned off, and the temperature is slightly lower than the heating target temperature, the compressor 110 may be turned on again.

That is, when the main circuit 100 reaches the heating target temperature and the indoor / outdoor temperature difference decreases, the compressor 110 repeatedly turns on and off, and in this case, the indoor / outdoor temperature difference is small so that the compressor 110 ) Is driven at low frequencies (Hz).

The controller 200 according to the present invention sets the target opening degree of the injection valve 153 by considering not only the outdoor temperature but also the frequency of the compressor 110. In addition, the controller 200 increases or decreases the target opening degree of the injection valve 153 in proportion to the frequency of the compressor 110.

Therefore, when the compressor 110 is driven at a low frequency, the controller 200 sets a small target opening degree of the injection valve 153. Thus, when the indoor and outdoor temperature difference of the main circuit 100 is very small and the compressor 110 is frequently turned on and off, the target opening degree of the injection valve 153 is set to be large so that the injection valve 153 Unnecessary opening can be prevented.

Meanwhile, even if the outdoor temperature of the main circuit 100 is higher than or equal to a predetermined set temperature, the controller 200 may determine that there is a request for injection of refrigerant according to the frequency of the compressor 110.

When there is a hot water load from the hot water unit 300, the frequency of the compressor 110 may increase. Therefore, the controller 200 may respond to the load by opening the injection valve 153 even if the outdoor temperature is greater than or equal to a predetermined set temperature.

Therefore, the injection valve 153 is opened not only in the low temperature region where the outdoor temperature is lower than the set temperature but also in other regions according to the operation state of the compressor 110, thereby injecting the refrigerant to ensure performance.

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

Referring to FIG. 4, the heat pump system according to another embodiment of the present invention further includes a heating unit 400 used for floor heating using water heated in the condenser 120. Since is similar to the first embodiment, detailed description of the same configuration is omitted, and the same reference numerals are used.

The heating unit 400 includes a heating pipe 401 extending from the connection pipe 304, a floor heating unit 410 for heating the floor of the room from the hot water delivered from the heating pipe 401, and the heating. It includes an air heating unit 420 for heating the air in the room from the hot water delivered from the pipe 401.

The floor heating unit 410 may be buried in a meander line (meander line) on the indoor floor.

The air heating unit 420 may be configured as a fan coil unit or a radiator.

The heating pipe 401 may be provided with heating hot water control valves 411 and 421 for guiding hot water to at least one of the floor heating unit 410 and the air heating unit 420.

The floor heating unit 410 is connected to the heating hot water control valve 411 and the floor heating pipe 412, the air heating unit 420 is the heating hot water control valve 421 and the air heating pipe 422. Leads to.

When the hot water control valve 306 is in the heating mode, water heated in the condenser 120 flows through the indoor unit pipe 302 and the connection pipe 304 in order to flow into the heating pipe 401, and the floor heating is performed. After heating at least one of the unit 410 and the air heating unit 420 is passed through the heating pipe 401, the connecting pipe 304 and the indoor unit pipe 302 in sequence and recovered to the condenser 120.

When the heating hot water control valves 411 and 421 are in the air heating mode, the hot water passes through the air heating pipe 422, the air heating unit 420, and the air heating pipe 422 in order, and the heating pipe 401. Is withdrawn. On the other hand, in the bottom heating mode, the hot water passes through the bottom heating pipe 412, the bottom heating unit 41 and the bottom heating pipe 412 in order to be discharged to the heating pipe 401.

As described above, even in the heat pump system including the hot water supply unit 300 and the heating unit 400, the controller 200 injects the refrigerant in consideration of the frequency of the compressor 110 as well as the outdoor temperature. As a result, the flow rate of the refrigerant is increased to ensure performance.

Those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the scope of the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and the equivalent concept are included in the scope of the present invention. Should be interpreted.

The heat pump system according to the present invention includes a control unit for detecting a plurality of operating variable values in real time and setting a target opening degree of the injection valve according to a change of the detected operating variable values, thereby providing an appropriate flow rate according to the operating state. Since the refrigerant can be injected, performance can be ensured.

1 is a view showing the configuration of a heat pump system according to an embodiment of the present invention.

2 is a block diagram showing a control flow of a heat pump system according to an embodiment of the present invention.

3 is a view illustrating a flow of a refrigerant during hot water supply operation of the heat pump system shown in FIG. 1.

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

BRIEF DESCRIPTION OF THE DRAWINGS Fig.

100: air conditioner 110; compressor

120: condenser 130: evaporator

141: first expansion valve 142: second expansion valve

150: injection heat exchanger 151: injection piping

153: injection valve 200: control unit

300: hot water supply unit 400: heating unit

Claims (10)

A compressor having a plurality of compression chambers, a condenser for condensing the refrigerant passing through the compressor, an expansion device for condensing the refrigerant passing through the condenser, an evaporator for evaporating the refrigerant expanded in the expansion device, A main circuit including an injection valve branched between evaporators and throttling refrigerant introduced into one of the plurality of compression chambers; A hot water supply unit that uses hot water heated by the condenser for hot water supply; And a control unit configured to detect a driving variable value of a plurality of operating variables in real time and to set a target opening degree of the injection valve according to a change in the detected operating variable value. The method according to claim 1, The operating variables include the frequency of the compressor and the outdoor temperature of the main circuit. The method according to claim 2, The control unit, And a preset value corresponding to the detected operating variable value. The method of claim 3, Respective setpoints for the plurality of operating variables independently vary the target opening of the injection valve. The method of claim 3, The control unit, And setting a target opening degree of the injection valve based on a linear combination of the set values. The method according to claim 2, The control unit, If the outdoor temperature of the main circuit is less than a predetermined set temperature, A heat pump system for opening said injection valve. The method according to claim 6, The control unit, If the outdoor temperature of the main circuit is higher than or equal to a predetermined set temperature, when there is a demand load of the hot water supply unit, A heat pump system that opens the injection valve in accordance with the frequency of the compressor. The method according to claim 2, The control unit, And a heat pump system for controlling the target opening of the injection valve to be proportional to the frequency of the compressor. The method according to claim 1, The expansion device, A first expansion device in which the refrigerant passing through the condenser is throttled; And a second expansion device disposed between the first expansion device and the evaporator, the second expansion device throttling refrigerant passing through the first expansion device. The method according to claim 1, And a heating unit that uses the water heated in the condenser for heating.

Images