KR101116927B1 - Heat pump system using ground heat source - Google Patents

Abstract

A geothermal heat pump system according to the present invention, comprising: a heat pump unit having a refrigerant pipe configured to circulate a refrigerant such as a compressor, a heat source side heat exchanger, an expansion device, and a load side heat exchanger, and a heat source side secondary fluid of the heat pump unit. A heat source unit having a heat source side heat exchanger and a heat source pipe formed to circulate an underground heat exchanger that exchanges heat with an underground heat source, and a load side secondary fluid circulates through a load side heat exchanger of the heat pump unit and a heat storage tank storing a load side secondary fluid. And a secondary heat exchanger for exchanging heat between the refrigerant discharged from the compressor in the heat pump unit and the heat source side secondary fluid flowing into the heat source side heat exchanger from the heat source unit. By such a configuration, the geothermal heat pump system according to the present invention can obtain hot water without using a separate device while using the capacity of the geothermal heat pump system as it is.

Description

Geothermal heat pump system {Heat pump system using ground heat source}

The present invention relates to a geothermal heat pump system that provides cooling and heating to a load such as a building using underground heat. More particularly, the present invention relates to a geothermal heat pump system capable of obtaining high temperature water, such as high temperature heating water or high temperature hot water, while maintaining cooling and heating, if necessary.

The geothermal heat pump system is an air conditioner that cools and heats a building by using an underground heat exchanger that exchanges heat with an underground heat source and a heat pump unit through which refrigerant is circulated. The geothermal heat pump system discharges heat in the building to the ground during cooling, and selectively absorbs the heat from the ground and supplies it to the building to perform cooling and heating operations.

1 is a view showing a conventional geothermal heat pump system. As shown in FIG. 1, the geothermal heat pump system includes a compressor 1a, a heat source side heat exchanger 1b, an expansion device 1c, a load side heat exchanger 1d, and a four-way valve 1e for switching the flow direction of the refrigerant. Is provided with a heat pump unit (1) comprising a. In the heat source side heat exchanger 1b, the refrigerant circulating in the heat pump unit 1 and the heat source side secondary fluid circulating in the underground heat exchanger 2 exchange heat. In addition, in the load-side heat exchanger 1d, the refrigerant circulating in the heat pump unit 1 and the load-side secondary fluid circulating in the heat storage tank 3 installed in a building or the like exchange heat.

The refrigerant circulating in the compressor 1a, the heat source side heat exchanger 1b, the expansion device 1c, and the load side heat exchanger 1d of the heat pump unit 1 circulates along the direction indicated by arrow A in FIG. In this case, heat is released from the load-side heat exchanger 1d and heating is performed. When the refrigerant circulates in the direction indicated by arrow B in FIG. 1, heat is absorbed from the load-side heat exchanger 1d and cooling is performed.

The heat storage tank 3 stores the load secondary fluid (eg, water) and supplies it to the load. The load is installed to perform cooling and heating in the building and the load side secondary fluid is circulated such as a fan coil unit or a circulating load (R) such as a building bottom pipe, and the load side 2 as cold water and hot water in the bathroom or kitchen provided in the building. The vehicle fluid includes the discharge load (W). For example, the heating side secondary fluid stored in the heat storage tank 3 is supplied to the circulation load R to heat the building and returns to the heat storage tank 3 again, and discharge load W ) So that the user can use hot water.

When using such a conventional geothermal heat pump system, water of 40 ° C. to 45 ° C. (hereinafter referred to as “hot water”) for supplying heating water and hot water is generally obtained. Heating water, hot water supply, etc., hereinafter referred to as 'hot water' was not sufficient. Therefore, in order to obtain hot water in addition to hot water in the conventional geothermal heat pump system, as shown in FIG. It was made. As the auxiliary heater 3a, an electric heater or the like was used. However, when the auxiliary heater 3a is used, the structure of the heat storage tank 3 becomes complicated, and there is a problem in that it is not economical in terms of energy efficiency.

In addition, a two-stage compression cycle or a variable speed compressor was used as a heat pump cycle to obtain hot water in a geothermal heat pump system. However, in the case of a geothermal heat pump system using a two-stage compression cycle, there is a problem in that the manufacturing cost is significantly increased due to a plurality of compressors. Due to the characteristics of the two-stage compression cycle, a gas-liquid separator and an intermediate heat exchanger are additionally disposed in the cycle to design the cycle. There are complex and consequent spatial or manufacturing problems. In addition, the geothermal heat pump system using the two-stage compression cycle generates various operating variables, which makes the system optimization and stability process for stable operation of the system quite complicated and also difficult to secure.

In addition, in the case of a geothermal heat pump system using a variable speed compressor, the variable speed compressor normally operates according to the rated rotational speed, but performs a high speed rotation when there is a demand for high temperature water. At this time, the process of increasing the load of the compressor is involved. Due to the variable operation of the compressor, the operating conditions of the entire system of the heat pump for mismatching of the heat exchanger and the optimization of the system are changed relatively, and the system efficiency according to the operating conditions is reduced. This results in degradation of the performance of the heat pump. In addition, there is a difficulty in employing an electronic expansion valve equipped with a separate control drive rather than a temperature-sensitive expansion valve having a mechanically simple structure that has been widely used in terms of system matching due to the increase in the number of compressor rotations. . In addition, manufacturing cost or equipment complexity is required, such as the manufacture of a compressor driving driver according to the adoption of an inverter for changing the compressor rotation speed and a separate equipment for removing noise.

The present invention is to solve the problems of the prior art, in the geothermal heat pump system that performs the cooling / heating operation for the load by using geothermal heat as a heat source, it is structurally simple and does not have a separate device of the geothermal heat pump system It is an object of the present invention to provide a geothermal heat pump system capable of obtaining hot water with high efficiency by using the capacity as it is.

In order to achieve the above object, a geothermal heat pump system according to the present invention includes a heat pump unit having a refrigerant pipe configured to circulate refrigerant through a compressor, a heat source side heat exchanger, an expansion device, and a load side heat exchanger, and a heat source side secondary fluid is A heat source unit having a heat source side heat exchanger of the heat pump unit and a heat source pipe formed to circulate the underground heat exchanger that exchanges heat with the underground heat source, and the load side secondary fluid stores the load side heat exchanger of the heat pump unit and the load side secondary fluid. A load unit having a load pipe configured to circulate the heat storage tank, and an auxiliary heat exchanger for exchanging heat between the refrigerant passing through the load side heat exchanger in the heat pump unit and the heat source side secondary fluid flowing from the heat source unit to the heat source side heat exchanger. It features.

With this configuration, the geothermal heat pump system according to the present invention has a heat source-side secondary fluid whose temperature rises by exchanging heat with a high temperature refrigerant passing through a load-side heat exchanger in an auxiliary heat exchanger, and a refrigerant into which the heat source-side heat exchanger flows into the heat source-side heat exchanger. The temperature of the refrigerant is increased, and the refrigerant having the elevated temperature is heat-exchanged with the load-side secondary fluid in the load-side heat exchanger to increase the temperature of the load-side secondary fluid, thereby obtaining hot water. Therefore, high temperature water can be obtained while using the capacity of the geothermal heat pump system without providing a separate device.

In the geothermal heat pump system according to the present invention, the heat source unit is branched from a branch point P1 which is a point of the underground heat exchanger outlet of the heat source pipe, and is a point of the secondary heat exchanger outlet via the auxiliary heat exchanger. And a heat source branch pipe that joins the heat source pipe again at the joining point (S1), wherein a control valve is installed between the branch point (P1) and the auxiliary heat exchanger in the heat source branch pipe. It is characterized in that the control valve is installed between the branch point (P1) and the confluence point (S1). By such a configuration, by adjusting the flow and amount of the secondary source fluid flowing into the auxiliary heat exchanger, it is possible to easily generate hot water at a time when hot water is required at a time when hot water is required, and the hot water generated The temperature can be adjusted.

In the geothermal heat pump system according to the present invention, the heat pump unit is branched from a branch point P2, which is a point of the outlet of the load-side heat exchanger in the refrigerant pipe, and is a point of the outlet of the auxiliary heat exchanger through the auxiliary heat exchanger. And a refrigerant branch pipe connected to the refrigerant pipe again at the phosphorus confluence point S2, wherein a control valve is installed between the branch point P2 and the auxiliary heat exchanger inlet at the refrigerant branch pipe. It characterized in that the control valve is installed between the branch point (P2) and the confluence point (S2) in the pipe. By such a configuration, by adjusting the flow and the amount of the refrigerant flowing into the auxiliary heat exchanger, the hot water can be easily generated at the time when the hot water is required, and the temperature of the hot water generated can be controlled.

In addition, in the geothermal heat pump system according to the present invention, the load unit, the heat storage pipe formed so that the load-side secondary fluid stored in the heat storage tank circulates the circulation load (R), and the heat storage from the load-side heat exchanger of the load pipe A discharge pipe branching from the branch point P3, which is a point of the load pipe where the load side secondary fluid flows into the tank, discharges the load side secondary fluid to the discharge load W, and the load side heat exchange from the heat storage tank in the load pipe. And a replenishment pipe communicating with the load pipe through which the load side secondary fluid flows, and for supplying the load side secondary fluid to the load pipe. The hot water generated by this configuration can be stored in the heat storage tank and circulated through the heat storage pipe to supply high temperature water to the circulation load for heating at a higher temperature, and also to discharge the hot water through the discharge pipe. Drain it into the kitchen or bathroom so that the user can use hot water.

In addition, in the geothermal heat pump system according to the present invention, an auxiliary heater is installed between the load side heat exchanger and the branch point (P3) of the load pipe, or between the heat storage tank and the branch point (P3) of the load pipe and auxiliary to the discharge pipe. It is characterized in that the heater is installed. By such a configuration, when the high temperature water of the required temperature cannot be supplied through the auxiliary heat exchanger of the heat pump unit, it is possible to raise the required temperature by using the auxiliary heater.

As described above, the geothermal heat pump system according to the present invention can obtain hot water while using the capacity of the geothermal heat pump system as it is without providing a separate device.

1 is a view showing a conventional geothermal heat pump system.
2 is a view showing Embodiment 1 of a geothermal heat pump system according to the present invention.
3 is a pressure-enthalpy diagram of a geothermal heat pump system according to the present invention.
4 shows a geothermal heat pump system according to another embodiment 2 according to the present invention.

Hereinafter, a geothermal heat pump system according to the present invention will be described in detail with reference to the accompanying drawings.

≪ Embodiment 1 >

2 is a view showing Embodiment 1 of a geothermal heat pump system according to the present invention. Referring to FIG. 2, the geothermal heat pump system according to the first embodiment includes a heat pump unit 100, a heat source unit 200, and a load unit 300.

First, the heat pump unit 100 includes a compressor 110 for compressing a refrigerant, a four-way valve 120 for switching a circulation direction of the refrigerant, and a load side heat exchanger 130 for exchanging heat with a load side secondary fluid flowing through the load unit 300. ), An expansion device 140 for expanding the refrigerant, and a heat source side heat exchanger 150 for exchanging heat with the heat source side secondary fluid flowing through the heat source unit 200. The compressor 110, the four-way valve 120, the load side heat exchanger 130, the expansion device 140, and the heat source side heat exchanger 150 are connected by a refrigerant pipe L100 through which a refrigerant flows.

Since the refrigerant direction is switched by the four-way valve 120, the direction of heat exchange in the load side heat exchanger 130 is changed, and as a result, cooling and heating are performed on the load. For example, as shown in the arrow direction shown in FIG. 2, the refrigerant passes through the compressor 110, through the load side heat exchanger 130, the expansion device 140, and the heat source side heat exchanger 150, and then back to the compressor 110. In the case of having a returning circulation direction, the load-side heat exchanger 130 exchanges heat with the load pipe L300 described later while the high-temperature and high-pressure refrigerant compressed by the compressor 110 flows through the refrigerant pipe L100. The load side secondary fluid flowing through the L300 is heated to heat the load. On the contrary, when the circulating direction is switched by the four-way valve 120 to be opposite to the direction of the arrow shown in FIG. 2, that is, the refrigerant compressed in the compressor 110 is heat source-side heat exchanger 150, expansion device 140, and the like. In the case of returning back to the compressor 110 through the load side heat exchanger 130, since the refrigerant in the load side heat exchanger 130 is in a low temperature and low pressure state, heat is removed from the load side secondary fluid flowing through the load pipe L300. . As a result, cooling is performed on the load.

This Embodiment 1 is for supplying high temperature water (for example, water having a temperature higher than hot water of 40 ° C to 45 ° C) used for heating or hot water supply, and thus mainly applies to heating. The case where mainly heating is performed in the unit 100 is demonstrated.

The heat source unit 200 includes an underground heat exchanger 210 that exchanges heat with an underground heat source, and the heat source side secondary fluid circulating through the heat source unit 200 includes the ground heat exchanger 210 and the heat pump unit 100. The inside of the heat source pipe (L200) connecting the heat source side heat exchanger (150) flows. The heat source pipe L200 is provided with a pump 220 for flowing the heat source side secondary fluid.

On the other hand, the heat pump unit 100 of the first embodiment is a secondary heat exchanger 160 in which the refrigerant of the heat pump unit 100 and the heat source side secondary fluid of the heat source unit 200 in addition to the heat source side heat exchanger 150 exchanges heat. ) Is further provided. In detail, the auxiliary heat exchanger 160 is connected between the outlet of the load side heat exchanger 130 and the expansion device 140 in the heat pump unit 100 and the underground heat exchanger 210 and the heat source side heat exchanger in the heat source unit 200. It is installed between the machines 150.

In addition, the heat source unit 200 is provided with a heat source branch pipe (L210) branched from the heat source pipe (L200) and passes through the auxiliary heat exchanger (160) in order for the heat source side secondary fluid to flow through the auxiliary heat exchanger (160). . The heat source branch pipe L210 branches from the branch point P1, which is one point of the outlet of the underground heat exchanger 150 in the heat source pipe L200 (the outlet of the pump 220 in FIG. 2), and passes through the auxiliary heat exchanger 160. After that, the heat source pipe (L200) is joined again at the joining point (S1).

And the control valve 221 is installed between the branch point (P1) and the auxiliary heat exchanger 160 in the heat source branch pipe (L210), and between the branch point (P1) and the confluence point (S1) in the heat source pipe (L200). The control valve 222 is installed. Each of the control valves 221 and 222 is an opening and closing valve that is selectively opened and closed by a control signal of a controller (not shown) and the degree of opening is adjusted. In general, when generating hot water, the control valve 222 maintains an open state, and the control valve 221 maintains a closed state to prevent the heat source side secondary fluid from passing through the auxiliary heat exchanger 160. On the other hand, when hot water having a temperature higher than hot water is required, a part of the heat source side secondary fluid flowing through the heat source pipe L200 by opening the control valve 221 together with the control valve 222 open is the auxiliary heat exchanger 160. After passing through the heat source-side secondary fluid flowing through the heat source pipe (L200) at the confluence point (S1) again to flow into the heat source side heat exchanger (150). The amount of the heat source side secondary fluid flowing into the auxiliary heat exchanger 160 can be adjusted by adjusting the opening and closing degree of the control valve 221.

In the first embodiment, two control valves 221 and 222 are provided to control the flow of the heat source side secondary fluid toward the auxiliary heat exchanger 160. However, the present invention is not limited thereto and can be variously changed. have. For example, a three-way valve (not shown) can be provided at the position of the branch point P1.

Meanwhile, the load unit 300 includes a load pipe L300 through which the load side secondary fluid flows, as shown in FIG. 2, and the load pipe L300 has a load side heat exchanger 130 and a load side secondary fluid. It is connected to pass through the heat storage tank 310 for storing the secondary fluid and the pump 320 for circulating the load-side secondary fluid.

The heat storage tank 310 is a storage space for storing the load side secondary fluid, and the load side secondary fluid (specifically, water) circulated by the pump 320 is the load side heat exchanger 130 of the heat pump unit 100. It is a space where hot water or high temperature water is stored by receiving heat from a high temperature refrigerant.

The heat storage tank 310 is connected through the circulation load (R) and the heat storage pipe (L310) through which the load-side secondary fluid circulates, such as a fan coil unit or a building bottom pipe installed in the building. The heat storage pipe (L310) is provided with a pump 350 for circulating the load-side secondary fluid stored in the heat storage tank (310). The heat storage pipe (L310) is supplied to the load-side secondary fluid, which is hot water in order to heat the circulation load (R) of the building, etc. Specifically, the pump 350 is operated to be stored in the heat storage tank (310) When the load-side secondary fluid circulates along the heat storage pipe L310, heat is released from the load-side secondary fluid to the circulation load R to heat the building or the like.

On the other hand, inside the heat storage tank 310 is provided with a water level sensor not shown, to maintain a constant water level at all times. The supplemental pipe L320 for supplying the load side secondary fluid (water) from the outside is connected to the outlet of the heat storage tank 310 toward the load side heat exchanger 130 among the load pipe L300. Therefore, when the constant level is not maintained, the load-side secondary fluid (water) is supplied from the outside through the replenishment pipe (L320). In addition, the load pipe (L300) between the supplemental pipe (L320) and the heat storage tank (310) is provided with a control valve (330) for opening and closing the load pipe (L300).

In addition, the load unit 300 is a branch point P3 which is one point of the load pipe L300 in which the load side secondary fluid flows from the load side heat exchanger 130 to the heat storage tank 310 among the load pipes L300 having a circulation structure. Branched from, and has a discharge pipe (L330) for discharging the load-side secondary fluid to the discharge load (W). That is, when the load side secondary fluid circulating the load pipe (L300) to flow to the discharge pipe (L330), the load side secondary fluid is discharged to the discharge load (W) such as kitchen or bathroom can be used by the user. In order to allow the load side secondary fluid to flow to either the load pipe L300 or the discharge pipe L330, a control valve 340 for switching the flow direction of the load side secondary fluid is installed at the branch point P3. Specifically, the control valve 340 is a three-way valve to switch the direction in which the load side secondary fluid flows by a controller (not shown). That is, when hot water or hot water is supplied to the circulating load R, the load side secondary fluid flows through the load pipe L300, and when hot water or hot water is supplied to the discharge load W, the load side 2 is supplied. The vehicle fluid is controlled to flow through the discharge pipe (L330).

In Embodiment 1, an example of controlling the flow of the load side secondary fluid using a three-way valve as the control valve 340 is provided, but the present invention is not limited thereto and may be variously changed. For example, an opening / closing valve for opening / closing the discharge pipe L330 and the load pipe L300 with a branch point P3 of the load pipe L300 through which the discharge pipe L330 is branched is provided. By controlling the opening and closing of the valve, the flow of the secondary fluid on the load side can be controlled.

In addition, the auxiliary heater 360 is installed between the load side heat exchanger 130 and the branch point P3 of the load pipe (L300). The auxiliary heater 360 serves to heat the load-side secondary fluid passing through the load pipe L300 by being heated by electricity. Specifically, when the load side secondary fluid flowing through the load pipe L300 to the circulating load R or the discharge load W has a temperature smaller than the temperature required for the circulating load R or the discharge load W. The secondary heater 360 supplies the load side secondary fluid to the circulation load R or the discharge load W according to the required temperature by applying heat using the auxiliary heater 360.

In addition, in the present Embodiment 1, one auxiliary heater 360 is installed, but two auxiliary heaters 360 are provided between the heat storage tank 310 and the branch point P3 and the discharge pipe L330 in the load pipe L300. You may install it. In this case, there is an advantage in that the temperature of the secondary side fluid supplied to the circulation load (R) and the discharge load (W) can be individually controlled.

On the other hand, when the load side secondary fluid is discharged to the discharge load (W) through the discharge pipe (L330), the amount of the load side secondary fluid flowing through the load pipe (L300) is reduced, thereby the load side stored in the heat storage tank (310) The level of secondary fluid is lowered. At this time, the load-side secondary fluid (water) is supplied from the outside through the replenishment pipe (L320) to replenish the reduced load-side secondary fluid.

The operation of the geothermal heat pump system according to the first embodiment having such a configuration will be described below. 3 is a pressure-enthalpy diagram of a geothermal heat pump system according to the present invention.

First, the case where hot water is supplied to the circulation load R or the discharge load W will be described. In this case, the refrigerant is circulated in the direction of the arrow shown in the heat pump unit 100 of FIG. 2, and in the heat source unit 200, the control valve 222 is opened and the control valve 221 is controlled to be closed. Thus, the heat source side secondary fluid is circulated through the heat source pipe L210 without passing through the auxiliary heat exchanger 160.

At this time, the state of the refrigerant of the heat pump unit 100 is changed along the cycle of a1-b1-c1-d1 of FIG. Specifically, when the compressor 110 is compressed to a high temperature and high pressure state, the refrigerant becomes a state of b1 in a1 state, and then the refrigerant flows through the load side heat exchanger 130 and the load side secondary fluid flowing through the load pipe L300. Heat exchange. As a result, heat loss occurs in the refrigerant, whereby the enthalpy is reduced to a c1 state. At this time, the load-side secondary fluid passing through the load-side heat exchanger 130 absorbs heat from the refrigerant and the temperature is increased to become the temperature of T _H1 . The refrigerant exiting the load-side heat exchanger 130 passes through the auxiliary heat exchanger 160. At this time, since the heat source side secondary fluid does not pass through the auxiliary heat exchanger 160, there is no heat transfer to the heat source side secondary fluid. Is introduced into the expansion device 140.

Thereafter, while expanding through the expansion device 140, the pressure is decelerated to a state of d1. In addition, the refrigerant exiting the expansion device 140 is introduced into the heat source side heat exchanger 150 to absorb heat by heat exchange with the heat source side secondary fluid passed through the underground heat exchanger 210 from the heat source side heat exchanger 150. . At this time, the temperature of the secondary fluid of the heat source side is called T _L1 .

The load side secondary fluid that absorbs heat from the refrigerant while passing through the heat source side heat exchanger 130 in the load unit 200 is hot water in a temperature state of T _{H1, and} the heat storage tank 310 is switched by switching of the control valve 340. Or it is selectively flowed to the discharge pipe (L330). That is, when heating by supplying hot water to the circulation load (R), the control valve 340 is controlled so that the load side secondary fluid (hot water) flows to the heat storage tank 310, the load side stored in the heat storage tank (310) The secondary fluid (hot water) is heated while passing through the circulation load R while circulating the heat storage pipe L310 by the pump 350. At this time, the control valve 330 located at the outlet of the heat storage tank 310 is maintained in the open state so that the load-side secondary fluid circulates the load pipe (L300).

In addition, when supplying hot water to the discharge load (W), such as kitchen or bathroom, the control valve 340 is controlled so that the load side secondary fluid (hot water) flows to the discharge pipe (L330). At this time, since the load side secondary fluid is discharged to the outside through the discharge pipe (L330), the load side secondary fluid (water) is supplied from the outside through the replenishment pipe (L320) to compensate for this. The supplied load side secondary fluid passes through the load side heat exchanger 130 and becomes hot water in a temperature state of T _H1 and flows to the discharge pipe L330. In addition, the control valve 330 located at the outlet of the heat storage tank 310 maintains a closed state to prevent the load side secondary fluid from the heat storage tank 310 to escape.

As described above, in the geothermal heat pump system according to the first embodiment, when the hot water is supplied, a high temperature is obtained by applying a predetermined work in the compressor 110 to the refrigerant heat-exchanged with the heat source side secondary fluid of the temperature T _L1 . In order to maintain the high pressure, heat is exchanged with the secondary fluid on the load side to generate the secondary fluid (hot water) at the temperature T _H1 . The generated load side secondary fluid (hot water) may be supplied to the circulation load R for heating, or to the discharge load W for hot water supply.

On the other hand, when the hot water of a temperature higher than the hot water described above for the circulation load (R) or the discharge load (W), the heat source side secondary flowing into the heat source side heat exchanger (150) through the auxiliary heat exchanger (160) It is controlled to raise the temperature of the fluid. Specifically, in the heat pump unit 100 of FIG. 2, the refrigerant circulates in the direction of the arrow as in the case of heating, and in the heat source unit 200, the control valve 221 is opened in a state where the control valve 222 is open. Open. This causes some of the heat source side secondary fluid flowing through the heat source pipe (L200) flows along the heat source branch pipe (L210), through the auxiliary heat exchanger (160) at the confluence point (S1) and back to the heat source pipe (L200). Flows into the side heat exchanger (150).

Through such control, the refrigerant and the heat source side secondary fluid in the auxiliary heat exchanger 160 perform heat exchange. That is, the refrigerant compressed to high temperature and high pressure by the compressor 110 passes through the load side heat exchanger 130 and supplies heat to the secondary side fluid of the load side, and then passes through the auxiliary heat exchanger 160 and heat source branch pipe (L210). Heat exchange is performed with a part of the heat source side secondary fluid which flows through). At this time, the refrigerant passing through the auxiliary heat exchanger 160 is deprived of heat in the load side heat exchanger 130, but is at a high temperature sufficient to supply heat to the heat source side secondary fluid passing through the auxiliary heat exchanger 160. Therefore, some of the heat source side secondary fluid is elevated in temperature while passing through the auxiliary heat exchanger 160, and then joins the heat source side secondary fluid which is not passed through the auxiliary heat exchanger 160 at the confluence point S1. As a result, the heat source side secondary fluid joined at the confluence point (S1) flows into the heat source side heat exchanger 150 along the heat source pipe (L200) at a higher temperature than when the hot water is supplied, and the heat source side heat exchanger. Heat exchange with the refrigerant flowing through the refrigerant pipe (L100) at 150 to supply heat to the refrigerant.

This will be described with reference to the pressure-enthalpy graph shown in FIG. 3. First, the heat source side secondary fluid whose temperature is raised by performing partial heat exchange through the auxiliary heat exchanger 160 becomes a temperature T _L2 higher than the temperature T _L1 when hot water is supplied. After that, the refrigerant in the refrigerant pipe L100 that is heat-exchanged with the heat source side secondary fluid of the temperature T _{L2 in} the heat source side heat exchanger 150 is changed into a state of d2 to a2 and flows into the compressor, where the state of a2 supplies hot water. The temperature becomes higher than the temperature of state a1. When the compressor 110 compresses the refrigerant by performing the same amount of work as the hot water is supplied, the refrigerant becomes state b2, and the state b2 becomes a temperature higher than the state b1 when the hot water is supplied. When the refrigerant in the state b2 flows into the load-side heat exchanger 130, the refrigerant exchanges heat with the load-side secondary fluid flowing through the load pipe L200 to be in the c2 state, while the load-side secondary fluid absorbs heat by heat exchange. To the temperature of T _H2 . The load side secondary fluid becomes hot water at a temperature T _H2 higher than the temperature T _H1 of the load side secondary fluid when hot water is supplied.

The generated hot water is selectively flowed into the heat storage tank 310 or the discharge pipe L330 by switching the control valve 340 as in the case of supplying hot water. Specifically, in the case of supplying hot water to the circulation load R, the control valve 340 is controlled such that the load side secondary fluid flows into the heat storage tank 310 and the load side secondary stored in the heat storage tank 310. The fluid is heated by the hot water while passing the circulation load R while circulating the heat storage pipe L310 by the pump 350. At this time, the control valve 330 located at the outlet of the heat storage tank 310 is maintained in the open state so that the load-side secondary fluid circulates the load pipe (L300).

In addition, when supplying hot water to the discharge load (W) such as kitchen or bathroom, the control valve 340 is controlled so that the load-side secondary fluid flows to the discharge pipe (L330). At this time, since the load side secondary fluid is discharged to the outside through the discharge pipe (L330), the load side secondary fluid (water) is supplied from the outside through the replenishment pipe (L320) to compensate for this. The supplied load side secondary fluid passes through the load side heat exchanger 130 and becomes high temperature water in the temperature state of T _H2 and flows to the discharge pipe L330. In addition, the control valve 330 located at the outlet of the heat storage tank 310 maintains a closed state to prevent the load side secondary fluid from the heat storage tank 310 to escape.

As described above, even if the geothermal heat pump system of the first embodiment uses the same capacity of the compressor 110, the geothermal heat pump system of the heat source side secondary fluid introduced into the heat source side heat exchanger 150 through the auxiliary heat exchanger 160 is used. By increasing the temperature, the temperature of the refrigerant passing through the heat source side heat exchanger 150 is increased, thereby increasing the temperature of the refrigerant compressed to high pressure by the compressor 110, thereby causing the load side secondary fluid to be heat exchanged in the load side heat exchanger 130. By raising the temperature of the high temperature water can be supplied. In other words, in FIG. 3, the temperature of the heat source side secondary fluid flowing into the heat source side heat exchanger 150 through the auxiliary heat exchanger 160 is increased by ΔT _L to T _L2 higher than the temperature T _L1 when hot water is supplied. The temperature of the secondary fluid of the load side is increased by ΔT _H to a temperature T _H2 higher than the temperature T _H1 when hot water is supplied, thereby generating hot water having a temperature T _H2 .

The geothermal heat pump system of the present embodiment 1 has a high temperature refrigerant passing through the load side heat exchanger 130 and the heat source side secondary fluid flowing into the heat source side heat exchanger 150 without having a separate heating device. By providing an auxiliary heat exchanger 160, a part of which heat exchanges, hot water having a temperature higher than hot water can be obtained. Therefore, since the geothermal heat pump system of the first embodiment does not use an external energy source, it has high energy efficiency.

On the other hand, when the temperature T _H2 of the hot water supplied by the geothermal heat pump system of the first embodiment is lower than the temperature actually required by the user, it is electrically heated by the auxiliary heater 360 provided in the load pipe L300. Can be adjusted to the required temperature. In this case, the auxiliary heater 360 is used. However, since the auxiliary heater 360 heats the hot water at a temperature higher than the hot water when the hot water is supplied by the geothermal heat pump system of the first embodiment to the required temperature, Compared with heating the hot water stored in the conventional heat storage tank 310 to a temperature required by the user using a heating device, the capacity of the electric heater is reduced, and is also advantageous in terms of energy efficiency.

In addition, the geothermal heat pump system according to the first embodiment can generate hot water and supply hot water to the discharge load W through the discharge pipe L300 even when the circulation load R is cooled. . Specifically, in the heat pump unit 100 illustrated in FIG. 2, when the refrigerant circulates in the direction opposite to the arrow direction without using the auxiliary heat exchanger 160, the heat storage tank 310 has a low-temperature load side secondary. Fluid (cold water) is stored. The stored load side secondary fluid (cold water) cools the circulating load R while circulating the heat storage pipe L310. When hot water is required at the discharge load W during this operation, the heat pump unit 100 circulates in the direction of the arrow shown in FIG. 2 to allow the load side secondary fluid to be hot water at a temperature T _H2 . At this time, the hot water generated by controlling the control valve 340 flows to the discharge load (R) through the discharge pipe (L330). In addition, the control valve 330 is closed to prevent cold water stored in the heat storage tank 310 from flowing out of the heat storage tank 310 to the load pipe L300, and also to load secondary fluid (water) from the supplemental pipe L320. Make it available.

In addition, the geothermal heat pump system according to the first embodiment uses heat exchange in the auxiliary heat exchanger 160 not only to obtain hot water but also to sufficiently secure the supercooling degree of the refrigerant flowing into the expansion device 140. can do. In the heat pump unit 100 that is ideally operated, the refrigerant passing through the load side heat exchanger 130 is maintained in a saturation state of the c1 state shown in FIG. 2. While the refrigerant flows from the saturation state to the expansion device 140, a portion of the refrigerant in the liquid state evaporates to a gaseous state due to the resistance of the pipe. When the refrigerant mixed with the gaseous state flows into the expansion device 140, the refrigerant flowing into the expansion device 140 is supercooled (ie, c1 in FIG. 2) because it hinders normal operation of the expansion device 140. It is necessary to maintain the liquid state (the state moved to the left side more).

In the geothermal heat pump system according to the first embodiment, when the refrigerant flowing into the expansion device 140 needs to reliably maintain the supercooling degree, the control valve 221 of the heat source side unit 200 is opened to open the heat source side. A portion of the secondary fluid may be controlled to be sent to the auxiliary heat exchanger 160. In this case, since the refrigerant flowing into the expansion device 140 from the heat pump unit 100 through the load-side heat exchanger 130 is heat exchanged with the secondary fluid in the heat source side of the auxiliary heat exchanger 160, heat is desorbed. The temperature is lower than that of the state so that the state becomes supercooled to maintain the liquid state. Therefore, the geothermal heat pump system of the first embodiment can control the subcooling degree of the geothermal heat pump system by the auxiliary heat exchanger 160.

≪ Embodiment 2 >

4 shows a geothermal heat pump system according to another embodiment 2 according to the present invention. In contrast to Embodiment 1 of FIG. 2, in Embodiment 1, the heat source branch pipe L210 branched from the heat source pipe L200 so that a part of the heat source side secondary fluid passes through the auxiliary heat exchanger 160 in the first embodiment. In the second embodiment, the refrigerant branch pipe L110 branched from the refrigerant pipe L100 is configured such that a part of the refrigerant of the heat pump unit 100 passes through the auxiliary heat exchanger 160. The rest of the configuration is the same. Therefore, about the same structure as Embodiment 2, the same code | symbol is used and the detailed description is abbreviate | omitted.

Specifically, the heat pump unit 100 of the second embodiment is branched at the branch point P2, which is one point of the outlet of the load-side heat exchanger 130, in the refrigerant pipe L100, and again at the outlet side of the auxiliary heat exchanger 160. Refrigerant branch line (L110) to be joined at the joining point (S2) that is one point. By such a configuration, some of the high temperature refrigerant flowing into the expansion device 140 through the load side heat exchanger 130 passes through the auxiliary heat exchanger 160, or both of the high temperature refrigerant passed through the load side heat exchanger 130. May be controlled to enter the expansion device 140 without passing through the auxiliary heat exchanger (160). To this end, a control valve 171 is installed between the branch point P2 and the auxiliary heat exchanger 160 in the refrigerant branch line L110, and between the branch point P2 and the confluence point S2 in the refrigerant line L100. The control valve 172 is installed. That is, in order to supply a part of the coolant to the auxiliary heat exchanger 160, the control valve 171 may be controlled to be opened while the control valve 172 is open, and conversely, the coolant may be supplied to the auxiliary heat exchanger 160. In the case where it is not necessary to supply the oil, the control valve 171 can be closed. In addition, as in the first embodiment, the amount of refrigerant supplied to the auxiliary heat exchanger 160 can be controlled by controlling the opening degree of the control valve 171.

On the other hand, in the second embodiment, the on / off flow of the refrigerant to the auxiliary heat exchanger 160 is opened or controlled using the on / off valves as the control valve 171 and the control valve 172, but the control valve is at the branch point P2. One three-way valve can be installed.

In the second embodiment, the heat source pipe L200 is configured such that the heat source side secondary fluid circulates through the underground heat exchanger 210, the auxiliary heat exchanger 160, and the heat source side heat exchanger 150.

In the second embodiment having such a configuration, similarly to the first embodiment, when hot water supply such as hot water supply is required, a part of the high temperature refrigerant flows into the auxiliary heat exchanger 160 by opening the control valve 171. In the auxiliary heat exchanger 160, the refrigerant flowing through the refrigerant branch pipe (L110) and the heat source side secondary fluid flowing through the heat source pipe (L200) exchange heat. As a result, the temperature of the heat source side secondary fluid flowing into the heat source side heat exchanger 150 is increased, and as a result, the temperature of the load side secondary fluid is raised as in the first embodiment. As a result, the load side secondary fluid can be used as hot water.

In addition, according to the second embodiment, even when it is necessary to subcool the refrigerant having exited the load heat exchanger 130, the secondary heat exchanger 160 may perform heat exchange between the refrigerant and the secondary source fluid on the heat source side.

As described above, the geothermal heat pump system according to the present invention has been described with reference to the preferred embodiments, but the present invention is not limited to these embodiments and is claimed by those skilled in the art. Various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention set forth herein.

For example, in Embodiment 1, the opening and closing of the control valve 221 is controlled by opening the control valve 222 in order to introduce part of the heat source side secondary fluid into the auxiliary heat exchanger 160 by way of example. However, by adjusting the opening degree of the control valve 222 or the opening and closing degree of the control valve 221 together, the amount of secondary fluid flowing into the auxiliary heat exchanger 160 along the heat source branch pipe line L210 is adjusted. I can regulate it. As a result, since the temperature of the heat source side secondary fluid flowing to the auxiliary heat source side heat exchanger 150 is controlled, the temperature of the hot water can be controlled.

In addition, in Embodiment 1, only the control valve 221 is provided and the control valve 222 does not need to be provided. That is, the heat source side secondary fluid always flows to the heat source side heat exchanger 150 and only adjusts the opening degree of the control valve 221 to adjust only the amount of the secondary source fluid flowing to the auxiliary heat exchanger 160 The effect similar to FIG. 1 can be achieved.

In addition, in the second embodiment, by adjusting the opening degree of the control valves 171 and 172 used to introduce the refrigerant into the auxiliary heat exchanger 160, the amount of the refrigerant flowing into the auxiliary heat exchanger 160 is adjusted. In addition, the amount of heat transferred from the auxiliary heat exchanger 160 to the heat source side secondary fluid may be adjusted. As a result, the temperature of the heat source side secondary fluid flowing to the heat source side heat exchanger 150 may be adjusted, and thus the temperature of the hot water may be controlled.

In addition, in Embodiment 2, only the control valve 171 is provided and it is not necessary to provide the control valve 172. That is, even if only the amount of the refrigerant flowing to the auxiliary heat exchanger 160 by adjusting the opening degree of the control valve 171 only by allowing the refrigerant to always flow to the expansion device 140 achieves the same effect as that of the second embodiment. can do.

In addition, Embodiment 1 of FIG. 2 and Embodiment 2 of FIG. 4 may be combined. Specifically, in order to control the heat source side secondary fluid flowing into the auxiliary heat exchanger 160 as in the first embodiment, the heat source pipe L200 is branched, and the second heat exchanger 160 is introduced as in the second embodiment. In order to control the refrigerant, a configuration for branching the refrigerant pipe L100 may be provided together.

The present invention can be used as a geothermal heat pump system that can obtain high-temperature hot water with higher efficiency than hot water, while cooling and heating buildings and the like using geothermal heat as a heat source.

In addition, although the present invention has been described with respect to a geothermal heat pump system using geothermal heat as a heat source, it can also be used in a heat pump system using other heat sources such as seawater heat as the heat source.

100: heat pump unit 110: compressor
120: four-way valve 130: load side heat exchanger
140: expansion device 150: heat source side heat exchanger
160: auxiliary heat exchanger 171, 172: control valve
200: heat source unit 210: underground heat exchanger
220: pump 221, 222: control valve
300: load unit 310: heat storage tank
320: pump 330: control valve
340: control valve 350: pump
360: auxiliary heater L100: refrigerant piping
L110: Refrigerant branch piping L200: Heat source piping
L210: Heat source branch piping L300: Load piping
L310: Regenerative piping L320: Supplementary piping
L330: Exhaust Pipe

Claims (8)

A heat pump unit including a compressor, a heat source side heat exchanger, an expansion device, and a refrigerant pipe configured to circulate refrigerant in a load side heat exchanger;
A heat source unit having a heat source side secondary fluid configured to circulate a heat source side heat exchanger of the heat pump unit and an underground heat exchanger which exchanges heat with an underground heat source;
A load unit having a load side heat exchanger configured to circulate a load side heat exchanger of said heat pump unit and a heat storage tank for storing said load side secondary fluid, and
And an auxiliary heat exchanger configured to exchange heat between the refrigerant passing through the load side heat exchanger in the heat pump unit and the heat source side secondary fluid flowing from the heat source unit to the heat source side heat exchanger. The method of claim 1
The heat source unit is branched from the branch point P1 which is one point of the outlet of the underground heat exchanger in the heat source pipe and merges with the heat source pipe again at the confluence point S1 which is one point of the outlet of the auxiliary heat exchanger via the auxiliary heat exchanger. Equipped with a heat source branch pipe,
Geothermal heat pump system, characterized in that the control valve is installed between the branch point (P1) and the auxiliary heat exchanger in the heat source branch pipe. The method of claim 2,
Geothermal heat pump system, characterized in that the control valve is installed between the branch point (P1) and the joining point (S1) in the heat source pipe. 4. The method according to any one of claims 1 to 3,
The heat pump unit is branched from the branch point P2, which is one point of the outlet of the load-side heat exchanger in the refrigerant pipe, and passes through the auxiliary heat exchanger again at the confluence point S2, which is a point of the outlet of the auxiliary heat exchanger. It has a refrigerant branch pipe to be connected,
Geothermal heat pump system, characterized in that the control valve is installed between the branch point (P2) and the auxiliary heat exchanger inlet in the refrigerant branch pipe. The method of claim 4, wherein
Geothermal heat pump system, characterized in that the control valve is installed between the branch point (P2) and the confluence point (S2) in the refrigerant pipe. The method of claim 5,
The load unit,
A heat storage pipe formed such that the load-side secondary fluid stored in the heat storage tank circulates the circulation load (R);
A discharge pipe branching from the load side heat exchanger from the load side heat exchanger to the heat storage tank from a branch point P3 which is a point of the load pipe through which the load side secondary fluid flows, and discharging the load side secondary fluid to the discharge load W;
Geothermal heat pump characterized in that it is in communication with the load pipe that the load side secondary fluid flows from the heat storage tank to the load side heat exchanger of the load pipe, and to supply the load side secondary fluid to the load pipe system. The method of claim 6,
Geothermal heat pump system, characterized in that the auxiliary heater is installed between the load side heat exchanger and the branch point (P3) of the load pipe. The method of claim 6,
Geothermal heat pump system, characterized in that the auxiliary heater is installed between the heat storage tank and the branch point (P3) of the load pipe and the discharge pipe.

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