KR101673846B1 - Method for controlling oil recovery in heatpump system, and heatpump system with oil recovery control fuction - Google Patents

Abstract

The present invention relates to a method to control an oil recovery in a heat pump system and a heat pump system with oil recovery control function. More particularly, the heat pump system with oil recovery control function comprises: a compressor to compress a coolant to discharge a high temperature and pressure coolant; a first plate type heat exchanger to receive the coolant discharged from the compressor to heat a source water received from a separate raw water line to produce hot water under a heating mode, and to allow the coolant to absorb the heat of the source water and evaporate to produce the cold water under a cooling mode; a second plate type heat exchanger to receive the coolant to absorb external heat introduced through a separate external heat source line and evaporate under the heating mode, and to receive the coolant discharged from the compressor to discharge the heat to the external heat source and condense under the cooling mode; an expansion valve to expand the coolant discharged from the first plate type heat exchanger under the heating mode, and to expand the coolant discharged from the second plate type heat exchanger under the cooling mode; a directional control valve to allow the coolant discharged from the compressor to flow into the first plate type heat exchanger under the heating mode, and to allow the coolant discharged from the compressor to flow into the second plate type heat exchanger under the cooling mode; and a control unit to control the directional control valve to switch the coolant over to an oil recovery mode as a reverse cycle during a predefined time, when a compression ratio is at a predefined value or less based on the compression ratio of the compressor.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a heat pump system having an oil recovery operation control method and a oil recovery operation control function of a heat pump system,

The present invention relates to a heat pump system having an oil recovery operation control method and a oil recovery operation control function of a heat pump system. More particularly, the present invention relates to a heat pump system control method for a heat pump system capable of recovering oil remaining in a plate type heat exchanger by a periodic oil recovery operation during a low compression ratio operation and a heat pump system .

Generally, in a residential space such as a residence or in a work and work space such as an office or a factory, the cooling of the summer and the heating of the winter are emerging as factors of the main living environment. Recently, The demand for energy for cooling and heating is rapidly increasing due to the increase of factory sites and offices.

Compared with the increase in energy demand, the supply of energy is not able to keep up with the demand due to the increase in the prices of fossil fuels such as petroleum and natural gas, and environmental pollution caused by soot generated in the combustion process of fossil fuels. Especially in urban baths, onshore farms, and livestock farmhouses, the cost of supplying cold and hot water due to the rise in the price of fossil fuels, as well as the burden of heating and cooling costs, are causing severe management pressure.

In order to overcome these factors, recently, there has been proposed a method for simultaneously performing cold and hot water supply, cooling and heating without causing pollution by using heat generated and recovered in the process of compressing, condensing, and evaporating refrigerant gas Pump system is widely used. The heat pump system can supply hot water and cold water at a low cost, and is an economical and environment-friendly system capable of performing cooling and heating by arranging a blower or an electric heating pipe in various ways.

Fig. 1 shows the structure of a conventional heat pump system 1. As shown in Fig. When the conventional heat pump system 1 is operated in the heating mode, the high-temperature and high-pressure refrigerant discharged from the compressor 10 flows through the first heat exchanger (not shown) operated as a condenser through the directional valve 20, (2), the refrigerant emits heat to the raw water flowing through the raw water line to produce hot water and to be condensed. The condensed refrigerant is evaporated through the second heat exchanger (3) after passing through the expansion valve (60). That is, in the heating mode, the second heat exchanger 3 is operated as an evaporator. In the second heat exchanger (3), the refrigerant absorbs heat from an external heat source flowing through a separate external heat source line and is evaporated. The refrigerant evaporated in the second heat exchanger (3) flows into the compressor (10) through the direction switching valve (20) and circulates.

When the heat pump system 1 is operated in the cooling mode, the high-temperature and high-pressure refrigerant discharged from the compressor 10 flows into the second heat exchanger 3 via the direction switching valve 20. In the cooling mode, it can be seen that the second heat exchanger 3 operates as a condenser and condenses while releasing heat by an external heat source. The refrigerant condensed in the second heat exchanger 3 flows into the first heat exchanger 2 via the expansion valve 60. In the cooling mode, the first heat exchanger 3 operates as an evaporator, And the raw water is cooled so that the refrigerant absorbs the heat of the raw water flowing through the evaporator and is evaporated. The refrigerant evaporated through the first heat exchanger (2) flows into the compressor (10) through the direction switching valve (20) and is circulated.

In the case of the heat pump system 1 for heating and cooling, most of the outdoor heat sources use external air. However, when the external air is used, a separate blower is required. do.

Further, geothermal heat, seawater, and wastewater can be used as the outside heat source. In the case of the compressor 10 used in such a geothermal heat pump system, the oil is circulated in order to prevent mechanical wear in the rotating part (rotary scroll) inside the compressor 10 as the compressor rotates at a high speed of 3500 rpm.

During operation, the oil is discharged to the external refrigerant cycle system rather than to the inside of the compressor 10, so that the compressor is damaged if the discharged oil is not recovered.

However, in the case of a geothermal heat pump system, a plate type heat exchanger is used. In the plate type heat exchanger structure, the oil discharged to the outside accumulates in the plate type heat exchanger, There is a problem that performance and efficiency are lowered.

The reason why the oil recovery is difficult is that the refrigerant flow rate inevitably occurs due to the structure of the plate heat exchanger. This phenomenon is particularly serious when the low compression ratio operation is performed. (In the case of low compression ratio operation, when the temperature of the load side is high or when the temperature of the heat source side is low during the cooling, the load side temperature is low or the heat source side temperature is high. .

Therefore, it is required to develop a heat pump system capable of periodic oil recovery operation at low compression ratio.

Korean Patent No. 1309210 Korea Patent No. 1095483

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is therefore one of the objects of the present invention to provide an apparatus and method for recovering oil remaining in a plate heat exchanger And to provide a heat pump system having an oil recovery operation control method and a oil recovery operation control function of a heat pump system.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. It can be understood.

A first object of the present invention is to provide a compressor for compressing a refrigerant and discharging a refrigerant at a high temperature and a high pressure; In the heating mode, the refrigerant discharged from the compressor flows in, and the raw water flowing through the separate raw water line is heated to produce hot water to be condensed. In the cooling mode, the refrigerant absorbs the heat of the raw water and evaporates to produce cold water. heat transmitter; A second plate type heat exchanger in which a refrigerant flows in a heating mode and is evaporated by absorbing an outside air heat source introduced through a separate outside heat source line, a refrigerant discharged from the compressor flows in a cooling mode and is condensed by discharging heat to an outside heat source; An expansion valve for expanding the refrigerant discharged from the first plate heat exchanger in the heating mode and expanding the refrigerant discharged from the second plate heat exchanger in the cooling mode; A direction switching valve for introducing the refrigerant discharged from the compressor in the heating mode into the first plate heat exchanger and the refrigerant discharged from the compressor in the cooling mode into the second plate heat exchanger; And a controller for controlling the directional switching valve to switch the refrigerant in an inverse cycle to an oil recovery mode for a predetermined time when the compression ratio becomes equal to or less than a predetermined value based on a compression ratio of the compressor. Can be achieved as a heat pump system having an operation control function.

In the oil recovery mode, oil remaining in the first plate heat exchanger and the second plate heat exchanger may be recovered by the compressor.

The control unit may further include a compression ratio measuring unit that measures a compression ratio based on the pressure values of the high pressure side and the low pressure side of the compressor. When the mode is switched from the heating mode to the oil recovery mode, When the mode is changed from the cooling mode to the oil recovery mode, the directional control valve is controlled to allow the refrigerant discharged from the compressor to flow into the first plate heat exchanger .

The apparatus may further include a temperature sensor for measuring the condensation temperature in real time.

The raw water line includes a raw water storage tank in which raw water is stored, a raw milk feed inlet provided between the raw water storage tank and the first plate type heat exchanger, and a raw water discharge pipe provided in the discharge end of the first plate type heat exchanger A raw water supply pump for pumping the raw water from the raw water storage tank to the first plate type heat exchanger, and a raw milk flow rate control valve for controlling the flow rate of the raw water.

The controller may control the raw water supply pump and the raw milk feed amount control valve to reduce the flow rate of the raw water flowing into the first plate type heat exchanger by a predetermined value in the oil recovery mode.

The control unit may determine the specific time based on the compression ratio measured by the compression ratio measuring unit, the temperature value measured by the temperature sensor, and the oil recovery mode duration measured by the oil recovery time measuring unit in the oil recovery mode, And when the predetermined time elapses, the directional control valve is controlled to end the oil recovery mode and return to the normal mode.

The outdoor heat source may be at least one of geothermal heat, wastewater, and seawater.

A second object of the present invention is to provide a method of controlling an oil recovery operation of a heat pump system operating in a heating mode, comprising: discharging high temperature and high pressure refrigerant from a compressor; The high temperature and high pressure refrigerant discharged from the compressor flows into the first plate heat exchanger through the direction switching valve to heat the raw water to produce hot water and to be condensed; The refrigerant flows into the second plate type heat exchanger through the expansion valve to absorb the outside heat source and evaporate; The refrigerant discharged from the second plate heat exchanger flows into the compressor again through the direction switching valve and circulates; When the compression ratio measured in real time by the compression ratio measuring unit becomes a predetermined value or less, the control unit controls the direction switching valve to introduce the refrigerant discharged from the compressor to the second plate heat exchanger, ; The oil of the first plate heat exchanger and the second plate heat exchanger is recovered to the compressor; And the control unit controls the direction switching valve to return the refrigerant discharged from the compressor to the first plate heat exchanger side and return to the heating mode after a predetermined time elapses. Oil recovery operation control method.

In the oil recovery mode, the control unit determines the specific time based on the compression ratio measured by the compression ratio measuring unit, the condensation temperature value measured by the temperature sensor, and the oil recovery mode duration measured by the oil recovery time measuring unit The control unit controls the directional switching valve to stop the oil recovery mode and to return to the heating mode.

A third object of the present invention is to provide a method for controlling an oil recovery operation of a heat pump system operating in a cooling mode, comprising: discharging high temperature and high pressure refrigerant from a compressor; The high-temperature and high-pressure refrigerant discharged from the compressor flows into the second plate type heat exchanger through the direction switching valve to discharge heat to the outside heat source and to be condensed; The refrigerant flows into the first plate type heat exchanger through the expansion valve to absorb the heat of the raw water to produce cold water and evaporate; The refrigerant discharged from the first plate heat exchanger flows into the compressor again through the direction switching valve and circulates; When the compression ratio measured in real time by the compression ratio measuring unit becomes a predetermined value or less, the control unit controls the direction switching valve so that the refrigerant discharged from the compressor flows into the first plate heat exchanger, ; The oil of the first plate heat exchanger and the second plate heat exchanger is recovered to the compressor; And controlling the directional control valve to return the refrigerant discharged from the compressor to the second plate type heat exchanger and returning to the cooling mode after a predetermined time elapses. Oil recovery operation control method.

In the oil recovery mode, the control unit determines the specific time based on the compression ratio measured by the compression ratio measuring unit, the condensation temperature value measured by the temperature sensor, and the oil recovery mode duration measured by the oil recovery time measuring unit The control unit controls the directional switching valve to stop the oil recovery mode and return to the cooling mode.

In the second and third objects of the present invention, in the oil recovery mode, the controller controls the raw water supply pump and the raw milk feed volume control valve to reduce the flow rate of raw water flowing into the first plate type heat exchanger by a predetermined value . ≪ / RTI >

According to one embodiment of the present invention, the oil remaining in the plate heat exchanger is recovered by the compressor by performing the periodic oil recovery operation during the low compression ratio operation, and the burnout can be prevented by improving the durability of the compressor.

It should be understood, however, that the effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those skilled in the art to which the present invention belongs It will be possible.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description, serve to further the understanding of the technical idea of the invention, It should not be construed as limited.
Fig. 1 is a configuration diagram of a heat pump system for cooling and heating,
2 is a block diagram illustrating a signal flow of a control unit according to an embodiment of the present invention;
3 is a flowchart of a method of controlling the oil recovery operation of the heat pump system in the heating mode according to the embodiment of the present invention,
FIG. 4A is a configuration diagram of a heat pump system having an oil recovery operation control function operated in a heating mode according to an embodiment of the present invention; FIG.
FIG. 4B is a configuration diagram of a heat pump system having an oil recovery operation control function in an oil recovery mode in a heating mode according to an embodiment of the present invention; FIG.
5 is a flowchart illustrating a method of controlling the oil recovery operation of the heat pump system in the cooling mode according to the embodiment of the present invention.
FIG. 6A is a configuration diagram of a heat pump system having an oil recovery operation control function operated in a cooling mode according to an embodiment of the present invention; FIG.
FIG. 6B is a configuration diagram of a heat pump system having an oil recovery operation control function that operates in an oil recovery mode in a cooling mode according to an embodiment of the present invention; FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, and advantages of the present invention will become more readily apparent from the following description of preferred embodiments with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

In this specification, when an element is referred to as being on another element, it may be directly formed on another element, or a third element may be interposed therebetween. Also in the figures, the thickness of the components is exaggerated for an effective description of the technical content.

Embodiments described herein will be described with reference to cross-sectional views and / or plan views that are ideal illustrations of the present invention. In the drawings, the thicknesses of the films and regions are exaggerated for an effective description of the technical content. Thus, the shape of the illustrations may be modified by manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention are not limited to the specific forms shown, but also include changes in the shapes that are produced according to the manufacturing process. For example, the area shown at right angles may be rounded or may have a shape with a certain curvature. Thus, the regions illustrated in the figures have attributes, and the shapes of the regions illustrated in the figures are intended to illustrate specific forms of regions of the elements and are not intended to limit the scope of the invention. Although the terms first, second, etc. have been used in various embodiments of the present disclosure to describe various components, these components should not be limited by these terms. These terms have only been used to distinguish one component from another. The embodiments described and exemplified herein also include their complementary embodiments.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms "comprises" and / or "comprising" used in the specification do not exclude the presence or addition of one or more other elements.

In describing the specific embodiments below, various specific details have been set forth in order to explain the invention in greater detail and to assist in understanding it. However, it will be appreciated by those skilled in the art that the present invention may be understood by those skilled in the art without departing from such specific details. In some instances, it should be noted that portions of the invention that are not commonly known in the description of the invention and are not significantly related to the invention do not describe confusing reasons to explain the present invention.

Hereinafter, the structure and function of the heat pump system 100 having the oil recovery operation control function and the oil recovery operation control method according to the embodiment of the present invention will be described. 2 is a block diagram illustrating a signal flow of a controller 80 according to an embodiment of the present invention.

The heat pump system 100 having the oil recovery operation control function according to the embodiment of the present invention is provided with the compressor 10, the directional valve 20, the first plate heat exchanger 30 ), An expansion valve (60), a second plate heat exchanger (70), an external heat source line, a raw water line, and the like.

The heat pump system 100 having the oil recovery operation control function according to an embodiment of the present invention includes a temperature sensor 82 for measuring the condensation temperature in real time and a temperature sensor 82 for measuring the compression ratio of the compressor 10, And a compression ratio measuring unit (11) for measuring the differential pressure on the left side in real time. The oil recovery mode time measuring unit 81 measures the oil recovery mode operation time, and the like.

As will be described later, when the compression ratio is equal to or lower than a specific value set on the basis of the external temperature value measured by the temperature sensor 82 and the compression ratio of the compressor 10 measured by the compression ratio measuring unit 11, And controls the switching valve 20 to operate in reverse cycle to operate in the oil recovery mode. In order to reduce the flow rate of the raw water to about 10 to 30% of the rated flow rate in the oil recovery mode, And controls the feeding amount regulating valve 44. The controller 80 controls the oil recovery mode to return to the normal mode based on the oil recovery mode operation time, the compression ratio, and the temperature value measured by the oil recovery mode time measuring unit 81 during the oil recovery mode .

3 is a flowchart of a method of controlling the oil recovery operation of the heat pump system 100 in the heating mode according to the embodiment of the present invention. 4A is a block diagram of a heat pump system 100 having an oil recovery operation control function that operates in a heating mode according to an embodiment of the present invention. 4B is a block diagram of a heat pump system 100 having an oil recovery operation control function that operates in an oil recovery mode in a heating mode according to an embodiment of the present invention.

3 and 4A, when the heat pump system 100 having the oil recovery operation control function according to the embodiment of the present invention is operated in the heating mode, the high-temperature, high-pressure The refrigerant is discharged (S1). The high-temperature and high-pressure refrigerant discharged from the compressor 10 flows into the first plate-type heat exchanger 30, which is operated as a condenser by the direction switching valve 20, (S2). At this time, the controller 80 controls the direction switching valve 20 so that the refrigerant discharged from the compressor 10 flows into the first plate heat exchanger 30.

In the first plate heat exchanger (30), the coolant discharged from the compressor (10) and the raw water flowing through the raw water line are heat exchanged with each other. 4A, the raw water line includes a raw water storage tank 40 in which raw water is stored, a raw milk feed pipe 41 in which raw water of the storage tank 40 is discharged and introduced into the first plate heat exchanger 30, And a raw water discharge pipe 42 through which the raw water of the first plate heat exchanger 30 is discharged and is provided at one side of the raw water line so that the raw water of the raw water storage tank 40 is supplied to the first plate heat exchanger 30 A raw water supply pump 43 for pumping the raw water to one side of the raw water line and a raw milk feeding amount control valve 44 for controlling the flow rate of the raw water.

When the first plate heat exchanger 30 is operated as a condenser, the heat of the refrigerant is transferred to the raw water to produce hot water, and the refrigerant is condensed (S3). The condensed refrigerant is discharged from the first plate heat exchanger 30, expanded through the expansion valve 60, and then introduced into the second plate heat exchanger 70 operated by the evaporator (S4).

In the second plate type heat exchanger (70), the refrigerant and the outside air heat source are heat exchanged. That is, the external heat source flows into the second plate type heat exchanger 70 through the external heat source line, and the refrigerant absorbs the heat of the external heat source and is evaporated (S5). The external heat source may be geothermal, seawater or wastewater.

Then, the evaporated refrigerant flows into the compressor 10 through the direction switching valve 20 and is circulated (S6).

During this heating mode operation, the temperature sensor 82 measures the condensation temperature in real time and transmits the temperature value to the control unit 80. [ The compression ratio measuring unit 11 measures the pressure of the low pressure side through the low pressure sensor 13 provided on the inflow line of the compressor 10 and the high pressure sensor 12 provided on the discharge line side of the compressor 10 That is, the compression ratio, based on the measured high-pressure-side pressure, and transmits the measured pressure to the controller 80 in real time.

If the current compression ratio is less than or equal to the set specific value (S7), the control unit 80 switches the heat pump system 100 to the oil recovery mode (S8). This specific value may be, for example, about 2.0. When the compression ratio becomes 2.0 or less, the controller 80 controls the directional valve 20 to circulate the refrigerant in a reverse cycle as shown in FIG. 4B .

That is, when the refrigerant is operated in the reverse cycle in the heating mode, the refrigerant discharged from the compressor 10 flows into the second plate type heat exchanger 70 and flows in the opposite direction The refrigerant flows from the lower side to the upper side in the heating mode and the oil accumulated on the upper side flows in the oil recovery mode from the upper side to the lower side in the oil recovery mode, (10).

Also, in the first plate heat exchanger (30), the refrigerant flows in the reverse direction, and the oil remaining in the first plate heat exchanger (30) is recovered to the compressor (10) side.

In this oil recovery mode, the decrease in the amount of heat on the load side due to the reverse cycle operation is minimized through the raw water flow control and the operation is performed in the shortest possible time (for example, in the oil recovery mode, 30%).

That is, in the oil recovery mode, the controller 80 controls the raw water supply pump 43 and the raw milk feed volume control valve 44 to control the flow rate of the raw water flowing into the first plate heat exchanger 30 to about 10 To about 30%.

Further, the oil recovery mode time measuring unit 81 checks the duration of the oil recovery mode, and switches the oil recovery mode back to the heating mode based on the duration time, the compression ratio, and the condensation temperature value (S9) . This operation is continued until the system 100 is terminated (S10).

5 is a flowchart of a method for controlling the oil recovery operation of the heat pump system 100 in the cooling mode according to an embodiment of the present invention. 6A is a block diagram of a heat pump system 100 having an oil recovery operation control function that operates in a cooling mode according to an embodiment of the present invention. 6B is a block diagram of a heat pump system 100 having an oil recovery operation control function that operates in an oil recovery mode in a cooling mode according to an embodiment of the present invention.

5 and 6A, when the heat pump system 100 having the oil recovery operation control function according to the embodiment of the present invention is operated in the cooling mode, the high-temperature, high-pressure The refrigerant is discharged (S11), and the high temperature and high pressure refrigerant discharged from the compressor 10 flows into the second plate heat exchanger 70 operated by the condenser by the direction switching valve 20 constituted by four-way valves or the like (S12). At this time, the controller 80 controls the direction switching valve 20 so that the refrigerant discharged from the compressor 10 flows into the second plate heat exchanger 70.

In the second plate type heat exchanger (70), the refrigerant discharged from the compressor (10) and the heat source introduced through the outside air heat source line are heat exchanged with each other. When the second plate heat exchanger 70 is operated as a condenser, the heat of the refrigerant is transferred to the heat source of the outside air so that the refrigerant is condensed (S13). The condensed refrigerant is discharged from the second plate type heat exchanger 70, expanded through the expansion valve 60, and introduced into the first plate type heat exchanger 30 operated as an evaporator (S14).

In the first plate heat exchanger (30), the refrigerant and the raw water are heat-exchanged. That is, the raw water flows into the first plate type heat exchanger 30 through the raw water line, and the refrigerant absorbs the heat of the raw water to produce cold water and is evaporated (S15). Then, the evaporated refrigerant flows into the compressor 10 through the direction switching valve 20 and is circulated (S16).

During the cooling mode operation, the temperature sensor 82 measures the condensation temperature in real time and transmits the temperature value to the control unit 80. [ The compression ratio measuring unit 11 measures the low pressure side pressure measured by the low pressure sensor 13 provided on the inflow line of the compressor 10 and the low pressure side pressure measured by the high pressure sensor 12 provided on the discharge line of the compressor 10. [ The pressure difference, that is, the compression ratio, based on the high-pressure-side pressure is measured in real time and transmitted to the controller 80.

If the current compression ratio is less than or equal to the set specific value (S17), the control unit 80 switches the heat pump system 100 to the oil recovery mode (S18). The specific value may be, for example, about 2.0. When the compression ratio becomes 2.0 or less, the controller 80 controls the directional valve 20 to circulate the refrigerant in a reverse cycle as shown in FIG. 6B .

That is, when the refrigerant is operated in the reverse cycle in the cooling mode, the refrigerant discharged from the compressor 10 flows into the first plate heat exchanger 30, The refrigerant flows from the lower side to the upper side in the cooling mode and the oil accumulated on the upper side flows in the oil recovery mode from the upper side to the lower side in the oil recovery mode, (10).

Also, in the second plate type heat exchanger (70), the refrigerant flows in the opposite direction, and the oil remaining in the second plate type heat exchanger (70) is recovered to the compressor (10) side.

As described above, in this oil recovery mode, the decrease in the amount of heat on the load side due to the reverse cycle operation is minimized through the raw water flow rate control and the operation is performed in the shortest possible time (for example, Is about 10 ~ 30% of the rated flow).

That is, in the oil recovery mode, the control unit 80 controls the raw water supply pump 43 and the raw milk feed amount control valve 44 to control the flow rate of the raw water flowing into the first plate heat exchanger 30 to about 10 - To about 30%.

In addition, the oil recovery mode time measuring unit 81 checks the duration of the oil recovery mode, and switches the oil recovery mode back to the heating mode based on the duration time, the compression ratio, and the condensation temperature value (S19) . This operation is continued until the system is terminated (S20).

It should be noted that the above-described apparatus and method are not limited to the configurations and methods of the embodiments described above, but the embodiments may be modified so that all or some of the embodiments are selectively combined .

1: Conventional heat pump system
10: Compressor
11: Compression ratio measuring unit
12: High pressure sensor
13: Low pressure sensor
20: Directional switching valve
30: first plate heat exchanger
40: raw water storage tank
41: Feeding of raw milk
42: Raw water discharge pipe
43: raw water supply pump
44: Circulating fluid adjustment valve
51: Refrigerant flow control valve
60: expansion valve
70: Second plate heat exchanger
71: heat source inlet portion
72: Heat source discharge part
80:
81: Oil recovery mode time measuring unit
82: Temperature sensor
100: Heat pump system with oil recovery operation control function

Claims (13)

A compressor for compressing the refrigerant and discharging the refrigerant at a high temperature and a high pressure;
In the heating mode, the refrigerant discharged from the compressor flows in, and the raw water flowing through the separate raw water line is heated to produce hot water to be condensed. In the cooling mode, the refrigerant absorbs the heat of the raw water and evaporates to produce cold water. heat transmitter;
A second plate type heat exchanger in which a refrigerant flows in a heating mode and is evaporated by absorbing an outside air heat source introduced through a separate outside heat source line, a refrigerant discharged from the compressor flows in a cooling mode and is condensed by discharging heat to an outside heat source;
An expansion valve for expanding the refrigerant discharged from the first plate heat exchanger in the heating mode and expanding the refrigerant discharged from the second plate heat exchanger in the cooling mode;
A direction switching valve for introducing the refrigerant discharged from the compressor in the heating mode into the first plate heat exchanger and the refrigerant discharged from the compressor in the cooling mode into the second plate heat exchanger; And
A compression ratio measuring unit for measuring a compression ratio based on pressure values of the high pressure side and the low pressure side of the compressor;
A temperature sensor for measuring the condensation temperature in real time; And
When the compression ratio is less than or equal to a predetermined value based on the compression ratio of the compressor, when the mode is switched from the heating mode to the oil recovery mode, the directional valve is controlled to allow the refrigerant discharged from the compressor to flow into the second plate heat exchanger, And a control unit controlling the direction switching valve to allow the refrigerant discharged from the compressor to flow into the first plate heat exchanger when the mode is switched to the oil recovery mode,
Wherein the raw water line comprises:
A raw water discharge pipe provided in a discharge end of the first plate type heat exchanger, and a raw water discharge pipe provided in the raw water storage tank, wherein the raw water storage tank is provided between the raw water storage tank and the first plate heat exchanger, A raw water supply pump for pumping the raw water to the first plate type heat exchanger, and a raw milk feed volume control valve for regulating the flow rate of the raw water,
In the oil recovery mode,
The oil remaining in the first plate heat exchanger and the second plate heat exchanger is recovered by the compressor,
In the oil recovery mode,
The control unit controls the raw water supply pump and the raw milk feed amount control valve to reduce the flow rate of the raw water flowing into the first plate type heat exchanger by a predetermined value and to control the compression ratio measured by the compression ratio measuring unit, Wherein the predetermined time is determined based on the oil recovery mode duration measured by the recovery time measuring unit and the specific time is controlled by the lower and upper directional control valves to return the oil recovery mode to the normal mode. Heat pump system with oil recovery operation control function.
delete delete delete delete delete delete The method according to claim 1,
Wherein the outdoor heat source is at least one of geothermal heat, wastewater, and seawater.
A method for controlling an oil recovery operation of a heat pump system according to claim 1, wherein the method is operated in a heating mode,
A high-temperature and high-pressure refrigerant is discharged from the compressor;
The high temperature and high pressure refrigerant discharged from the compressor flows into the first plate heat exchanger through the direction switching valve to heat the raw water to produce hot water and to be condensed;
The refrigerant flows into the second plate type heat exchanger through the expansion valve to absorb the outside heat source and evaporate;
The refrigerant discharged from the second plate heat exchanger flows into the compressor again through the direction switching valve and circulates;
When the compression ratio measured in real time by the compression ratio measuring unit becomes a predetermined value or less, the control unit controls the direction switching valve to introduce the refrigerant discharged from the compressor to the second plate heat exchanger, ;
The oil of the first plate heat exchanger and the second plate heat exchanger is recovered to the compressor; And
Wherein the control unit controls the directional valve to return the refrigerant discharged from the compressor to the first plate heat exchanger and return to the heating mode after a predetermined time,
In the oil recovery mode,
The specific time is determined on the basis of the compression ratio measured by the compression ratio measuring unit, the condensation temperature value measured by the temperature sensor, and the oil recovery mode duration measured by the oil recovery time measuring unit, Wherein the oil recovery mode is ended and returned to the heating mode by controlling the oil recovery mode.
delete The method of controlling an oil recovery operation of a heat pump system according to claim 1, wherein the method is operated in a cooling mode,
A high-temperature and high-pressure refrigerant is discharged from the compressor;
The high-temperature and high-pressure refrigerant discharged from the compressor flows into the second plate type heat exchanger through the direction switching valve to discharge heat to the outside heat source and to be condensed;
The refrigerant flows into the first plate type heat exchanger through the expansion valve to absorb the heat of the raw water to produce cold water and evaporate;
The refrigerant discharged from the first plate heat exchanger flows into the compressor again through the direction switching valve and circulates;
When the compression ratio measured in real time by the compression ratio measuring unit becomes a predetermined value or less, the control unit controls the direction switching valve so that the refrigerant discharged from the compressor flows into the first plate heat exchanger, ;
The oil of the first plate heat exchanger and the second plate heat exchanger is recovered to the compressor; And
The control unit controls the directional valve to return the refrigerant discharged from the compressor to the second plate type heat exchanger and return to the cooling mode after a predetermined time,
In the oil recovery mode,
The specific time is determined on the basis of the compression ratio measured by the compression ratio measuring unit, the condensation temperature value measured by the temperature sensor, and the oil recovery mode duration measured by the oil recovery time measuring unit, Wherein the oil recovery mode is ended and returned to the cooling mode by controlling the oil recovery mode.
delete The method according to claim 9 or 11,
Wherein the controller controls the raw water supply pump and the raw milk feed amount control valve in the oil recovery mode to reduce the flow rate of the raw water flowing into the first plate heat exchanger by a predetermined value, .

Images