JPH1194367A - Heat pump system utilizing underground heat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct stable system operation by preventing the freezing of a heat medium, and contrive the improvement of system efficiency, the decrease in size of constituent apparatus, and the improvement of environmental preservation property, in a heat pump system utilizing underground heat. SOLUTION: In the constitution of performing the heating of the target building 1 by the calorie generated by a heat pump device 3, by circulating a heat medium W1 between a buried heat exchanger 4 for heat exchange with ground and the heat absorber 3b of a heat pump 3, this heat pump system uses water for the heat medium W1, and is provided with an exhausted hot water tank 8 to reserve the exhausted hot water produced in the target building 1. Then, this is provided with freezing preventive means 10B, Pb, Va, Vb, 15, and 12 which judge whether the water as the heat medium W1 is in a danger of freezing or not, and automatically heat the water as the heat medium W1, using the calorie that the reserved exhausted hot water in a exhausted hot water tank 8 preserves in condition of danger of freezing, based on the judgment results.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump system utilizing underground heat for heating by heating from underground.
Specifically, the heat medium is circulated between a buried heat exchanger for exchanging the heat medium with the ground and a heat absorbing portion of the heat pump device,
The present invention relates to an underground heat utilization heat pump system that heats a target building by using heat generated by the heat pump device.

[0002]

2. Description of the Related Art Conventionally, in this type of underground heat utilization heat pump system, an antifreeze liquid to which ethylene glycol or propylene glycol is added is used as a heat medium circulated between a buried heat exchanger and a heat absorbing portion of a heat pump device. This prevents the heat medium from freezing due to a decrease in the temperature during the heating period or a decrease in the temperature of the heat medium due to the operation of the heat pump device.

[0003]

However, the antifreeze liquid has a lower heat exchange performance than, for example, water, which limits the efficiency of the entire system to a low level, and requires system components such as a buried heat exchanger and a heat pump device. There is a problem that the system size is increased and the system cost is increased, and a safer heat medium instead of the antifreeze is demanded also from the viewpoint of environmental protection.

[0004] In view of the above circumstances, a main object of the present invention is to employ a rational anti-freezing structure, thereby obviating the need for using an antifreeze as a heat medium and effectively solving the above problem.

[0005]

[Means for Solving the Problems]

[1] According to the first aspect of the present invention, the heat pump device is operated using water as a heat medium circulated between the buried heat exchanger and the heat absorbing portion of the heat pump device. The target building is heated by the heat generated by the heat pump device in a form in which geothermal exchange is performed to collect heat from underground. Further, hot water generated in the target building (for example, hot water discharged from a bathtub) is stored in the hot water tank.

When water as a heat medium is in a danger of freezing due to a temperature drop or a temperature drop of the heat medium due to operation of a heat pump device, the water is stored in the hot water tank based on a determination result as to whether or not the water is in a danger of freezing. The water as a heat medium is automatically heated by the anti-freezing means using the retained heat of the waste water, thereby preventing the water as the heat medium from freezing.

That is, according to the first aspect of the present invention, while using water as the heat medium circulating between the buried heat exchanger and the heat absorbing portion of the heat pump device, the water is prevented from freezing and stable. System operation can be realized. By using water as the heat medium in this way, it is possible to ensure high heat exchange performance of the heat medium as compared with the case where an antifreeze is used as the heat medium as before, thereby improving the efficiency of the entire system. At the same time, it is possible to reduce the size of system components such as a buried heat exchanger and a heat pump device, thereby lowering the system cost, and to achieve a more excellent system in terms of environmental protection.

In addition, since the freezing prevention is performed by using the retained heat of the hot water generated in the target building, it is excellent in energy saving and the running cost for the prevention of freezing can be effectively avoided.

[2] According to the second aspect of the present invention, the first aspect
In implementing the described invention, hot water used in the target building is stored in a hot water tank.

In addition to determining whether or not there is a danger of freezing, the antifreezing means is also configured to determine whether or not the retained heat of the stored hot water in the hot water tank is less than a set lower limit.
Based on these determination results, in a situation where the water as a heat medium is in a danger of freezing, when the retained heat of the stored drainage in the drainage tank is equal to or greater than the set lower limit, heat is stored using the retained heat of the stored drainage in the drainage tank. The water as the medium is automatically heated by the anti-freezing means, thereby preventing the water as the heat medium from freezing.

On the other hand, in a situation where the water as the heat medium is in a danger of freezing, if the stored heat of the stored hot water in the hot water tank is less than the set lower limit, the stored heat of the stored hot water in the hot water tank is used as the heat medium. Is automatically heated by the anti-freezing means, thereby preventing freezing of water as a heat medium.

In other words, according to the second aspect of the present invention, the amount of generated hot water in the target building is insufficient, or the temperature of the stored hot water stored in the hot water tank is used up. Even if the temperature of the stored hot water in the hot water tank is insufficient, the system can automatically prevent freezing using the stored hot water in the hot water supply tank. can do.

[3] In the invention according to claim 3, the heat pump device is operated by using water as a heat medium circulated between the buried heat exchanger and the heat absorbing portion of the heat pump device, whereby the heat medium The target building is heated by the heat generated by the heat pump device in a form in which water is exchanged for heat with the ground to collect heat from the ground. In addition, hot water used in the target building is stored in a hot water tank.

When water as a heat medium is in a danger of freezing due to a decrease in air temperature or a temperature drop of the heat medium due to operation of the heat pump device, the water is stored in the hot water supply tank based on a determination result as to whether or not the water is in a danger of freezing. The freezing prevention means automatically heats the water as a heat medium using the retained heat of the hot water, thereby preventing freezing of the water as the heat medium.

That is, according to the third aspect of the present invention, similarly to the first aspect of the present invention, while using water as the heat medium circulated between the buried heat exchanger and the heat absorbing portion of the heat pump device, Stable system operation can be realized by preventing freezing of water. By using water as the heat medium in this way, it is possible to ensure high heat exchange performance of the heat medium as compared with the case where an antifreeze is used as the heat medium as before, thereby improving the efficiency of the entire system. At the same time, it is possible to reduce the size of system components such as a buried heat exchanger and a heat pump device, thereby lowering the system cost, and to achieve a more excellent system in terms of environmental protection.

Moreover, since the freezing is prevented by using the temperature of the hot water used for hot water supply, the system cost can be reduced as compared with, for example, adding a heater dedicated to preventing freezing to the heating medium piping system. it can.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a geothermal heat pump system using a house 1 as a building for cooling and heating.
Is a fan coil unit disposed in a house room, 3 is a heat pump device, and 4 is a double tube type embedded heat exchanger for exchanging water W1 as a heat source side heat medium with ground.

Reference numeral 5 denotes a built-in coil 2a of the fan coil unit 2 and a load side heat exchanger 3a of the heat pump device 3.
A load-side circulation path for circulating water W2 (hereinafter referred to as load-side heat medium water) as a load-side heat medium by a circulation pump Pc between the heat exchanger and the heat source-side heat of the embedded heat exchanger 4 and the heat pump device 3. This is a heat-source-side circulation path in which water W1 (hereinafter, referred to as heat-source-side heat medium water) as a heat-source-side heat medium is circulated with the exchanger 3b by a circulation pump Pa.

Regarding the operation, in the case of the heating operation, the load side heat exchanger 3a of the heat pump device 3 functions as a radiator (that is, a refrigerant condenser), and the heat pump device 3
The heat source side heat exchanger 3b functions as a heat absorbing portion (that is, a refrigerant evaporator), thereby circulating the heat source side heat transfer water W1 in the heat source side circulation path 6 as shown by a solid line arrow in the figure (normal circulation described later). ), The internal coil 2a of the fan coil unit 2 is taken while the heat is taken from the ground in the buried heat exchanger 4.
In this embodiment, the load-side heat transfer water W2 supplied to the heat pump device 3 is heated by the load-side heat exchanger 3a of the heat pump device 3, and the generated heat of the heat pump device 3 is used to heat the interior of the house.

On the other hand, in the cooling operation, on the other hand, the load side heat exchanger 3a of the heat pump device 3 is made to function as a heat absorbing portion (that is, a refrigerant evaporator), and the heat source side heat exchanger 3b of the heat pump device 3 is used as a heat radiating portion. (I.e., a refrigerant condenser), whereby the heat source side heat transfer water W1 is circulated in the heat source side circulation path 6 as shown by the solid line arrow in the figure, and the heat is radiated to the ground in the buried heat exchanger 4. Meanwhile, in a mode in which the load-side heat medium water W2 supplied to the internal coil 2a of the fan coil unit 2 is cooled by the load-side heat exchanger 3a of the heat pump device 3, the house room is cooled by the generated cold heat of the heat pump device 3.

Reference numeral 7 denotes a hot water tank for storing hot water used in the target house. Reference numeral 8 denotes a hot water tank for storing hot water generated in the target house (for example, hot water discharged from a bathtub). The hot water tank 7 and the hot water tank 8 are provided. Each of the heat source side heat medium water W1 guided from the outward path portion of the heat source side circulation path 6 through the heat medium introduction path 9 and each tank 7,
Heat exchangers 10A and 10 for exchanging heat with the stored hot water of No. 8
B, and these heat medium heat exchangers 10A, 10A.
The heat-source-side heat medium water W1 that has passed through B is returned to the return path portion of the heat-source-side circulation path 6 via the heat medium outlet path 11.

In the heat medium introduction passage 9, the heat source side heat medium water W1 is indicated by a solid line arrow by a heat source side circulation pump Pa in a state where the heat medium water inflow into the heat medium introduction passage 9 is cut off. The heating medium water flows into the heating medium introduction passage 9 by the sub-circulation pump Pb interposed in the heating medium introduction passage 9 and circulates the heat source side heating medium water W1 as indicated by a broken line arrow in the figure. In addition to the freeze prevention circulation to be performed, an introduction three-way valve Va for switching the circulation form of the heat source side heat medium water W1 is provided.
1 is a heat medium heat exchanger 1 of a hot water tank 7 in a parallel connection configuration.
0A or the heat medium heat exchanger 10B of the hot water tank 8 through which the heat source side heat medium water W1 is passed is selected.
b is provided.

7a is a hot water supply channel for sending the hot water stored in the hot water tank 7 to a hot water supply point of the target house, 7b is a supply water channel to the hot water tank 7;
Reference numeral 7c denotes a hot water supply heater for heating the water in the hot water supply tank 7, 8a denotes a hot water discharge path for introducing the hot water generated in the target house into the hot water discharge tank 8, and 8b denotes a hot water supply tank which has become unnecessary due to a low temperature or the like. 8 is a drainage channel for discharging the stored hot water.

Reference numeral 12 denotes a water temperature sensor for detecting the temperature tw of the heat-source-side heat transfer medium water W1 in the heat-source-side heat transfer passage 6 near the buried heat exchanger 4, and reference numeral 13 denotes a stored amount gy of the drained water in the drainage tank 8. A hot water quantity sensor, 14 is a hot water temperature sensor for detecting the temperature ty of the stored hot water in the hot water tank 8, and 15 is a control device for controlling the system based on the detection information of these sensors. As the control, the following anti-freezing control (see FIG. 2) is executed.

The detection temperature tw of the heat source side heat transfer water W1 detected by the water temperature sensor 12 is equal to the set freezing dangerous temperature t1 (for example, 2 ° C.).
If the heat pump device 3 is operating, the operation of the heat pump device 3 and the operation of the heat source side circulating pump Pa are stopped when the heat pump device 3 is operating, and those heat pumps that are already stopped when the heat pump device 3 is stopped. Device 3
In addition, the stop of the heat source side circulation pump Pa is omitted, and the introduction side three-way valve Va is switched to the side where the circulation form of the heat source side heat transfer water W1 is changed from the normal circulation to the freeze prevention circulation.

The hot water sensor 13 and the hot water temperature sensor 14
Is determined based on the detection information gy and ty of the stored hot water in the hot water tank 8 is less than a set lower limit qy (omitted in FIG. 2), and the stored hot water in the hot water tank 8 is set. When the lower limit amount qy is greater than or equal to the lower limit amount qy, the outlet side three-way valve Vb is switched to a side on which the inflowing heat medium water W1 from the heat medium introducing passage 9 passes through the heat medium heat exchanger 10B of the hot water tank 8, while the storage in the hot water tank 8 is performed. When the retained heat of the discharged hot water is less than the set lower limit qy, the outlet side three-way valve Vb is switched to a side on which the inflowing heat medium water W1 from the heat medium introduction passage 9 passes through the heat medium heat exchanger 10A of the hot water supply tank 7.

Then, the sub-circulation pump Pb is operated. When the retained heat of the stored hot water in the hot water tank 8 is equal to or more than the set lower limit qy, the hot water heat exchanger 10B on the side of the hot water tank 8 discharges the hot water from the hot water tank. 8, while heating the heat-source-side heat medium water W1 with the retained heat of the stored waste water, the heat-source-side heat medium water W1 is heated.
1 is circulated as indicated by the dashed arrow in the figure to prevent the heat source side heat transfer water W1 from freezing, and when the retained hot water of the stored hot water in the hot water tank 8 is less than the set lower limit qy, the hot water tank 7 The heat source-side heat medium water W1 is circulated as indicated by the dashed arrow in the figure while heating the heat source-side heat medium water W1 with the retained heat of the stored hot water in the hot water supply tank 7 in the heat medium heat exchanger 10A on the side of The freezing of the heat source side heat transfer water W1 is prevented.

During the antifreezing operation in which the heat-source-side heat medium water W1 is passed through the heat medium heat exchanger 10B of the hot water tank 8, the retained heat of the stored hot water in the hot water tank 8 becomes less than the set lower limit qy. If this happens, based on the determination, the outlet-side three-way valve Vb is switched to the side on which the heat-source-side heat medium water W1 passes through the heat medium heat exchanger 10A of the hot water tank 7, and the antifreeze operation is continued.

Thereafter, when the temperature tw detected by the water temperature sensor 12 of the heat source side heat transfer water W1 becomes equal to or higher than a safe temperature t2 (for example, 5 ° C.) higher than the set freezing dangerous temperature t1, the sub-circulation pump Pb is stopped. In addition, the freezing prevention operation is terminated, the introduction three-way valve Va is switched to a side where the circulation form of the heat source side heat transfer water W1 returns from the freezing prevention circulation to the normal circulation, and the outlet three-way valve Vb is returned to the predetermined state. Position (for example, a position where the passage of the heat medium water on the hot water tank 7 side is blocked, a position where the heat medium water passage on the side of the hot water tank 8 is blocked, or both the hot water tank 7 side and the hot water tank 8 side Switch to the position where the passage of heat medium water is blocked).

If the heat pump device 3 is operating before the above-mentioned antifreezing operation, the operation of the heat pump device 3 and the operation of the heat source side circulating pump Pa are restored, and the antifreezing operation is started. If the heat pump device 3 is stopped before entering, the return operation of the heat pump device 3 and the heat source side circulation pump Pa is omitted, and the detection temperature tw of the heat source side heat transfer water W1 by the water temperature sensor 12 is again set. Return to monitoring state.

In short, in the present embodiment, in the heating operation, water W1 is used as the heat medium on the heat source side circulated between the buried heat exchanger 4 and the heat absorbing portion 3a of the heat pump device 3 (radiating portion for cooling). .

In response to the use of water, the heat medium heat exchangers 10A and 10B of the hot water supply tank 7 and the hot water discharge tank 8, the auxiliary circulation pump Pb, the three-way valves Va and Vb on the inlet and outlet sides, the controller 15, and , The water temperature sensor 12 detects water W1 as a heat medium.
Is determined to be in a freezing danger state, and based on the determination result, when the water W1 as a heat medium is in a freezing danger state, the stored hot water stored in the drainage tank 8 is used, or hot water is supplied. A freezing prevention means for automatically heating the water W1 as a heat medium using the retained heat of the stored hot water in the tank 7 is configured.

In the present embodiment, the anti-freezing means determines whether or not the retained hot water stored in the hot water tank 8 is less than a set lower limit qy. In the situation where the water W1 is in a danger of freezing, when the stored heat of the stored hot water in the hot water tank 8 is equal to or greater than the set lower limit qy, the water W1 as the heat medium is automatically generated using the stored hot water of the stored hot water in the hot water tank 8. Heating, and
In a situation where the water W1 as the heat medium is in a danger of freezing, the retained heat of the stored hot water in the hot water tank 8 becomes the set lower limit qy.
When the temperature is less than the temperature, the water W1 as the heat medium is automatically heated using the stored heat of the stored hot water in the hot water supply tank 7.

In the drawing, the pipe length of a portion of the heat medium side circulation path 6 which does not perform anti-freeze circulation is substantially equal to the pipe length of a part which performs anti-freeze circulation. The length of the pipeline that does not perform antifreeze circulation should be as short as possible than that of the part that performs antifreeze circulation, and the part that does not perform antifreeze circulation should be placed in a place where there is no risk of freezing. In order to prevent the freezing of the heat transfer water in that part, for example, by performing dripping or performing a high degree of heat insulation treatment.

[Another Embodiment] Next, another embodiment will be described.

In the above-described embodiment, the water W1 as the heat medium is heated using the stored heat of the stored hot water in the hot water tank 8, and the heat medium as the heat medium is used using the stored heat of the stored hot water in the hot water tank 7. Both the mode of heating the water W1 and the mode of heating the water W1 are adopted. Instead, the water W1 as the heat medium is heated by using the retained heat of the stored hot water in one of the drainage tank 8 and the hot water supply tank 7. Only the form may be implemented.

In order to heat the water W1 as a heat medium using the stored heat of the stored hot water in the hot water tank 8 and the stored heat of the hot water in the hot water supply tank 7, the specific heating method is as follows. The heat medium heat exchangers 10B and 10A are built in the tank 7, but the present invention is not limited to the above-described embodiment. For example, water W1 as a heat medium is exchanged with hot water derived from the drainage tank 8 or the hot water supply tank 7. Various formats can be adopted, such as adopting a format that allows the user to make a request.

In the above-described embodiment, the circulation mode of the water W1 as the heat medium is switched from the normal circulation to the antifreeze circulation, and the water W1 as the heat medium is heated. For example, various modes can be adopted as a circulation mode at the time of heating, such as a mode of heating water W1 as a heat medium while maintaining the same normal circulation mode as in the heating operation.

In the above-described embodiment, the water W1 as the heat medium is used.
A temperature tw is detected, and a determination method for determining whether or not there is a danger of freezing based on the detected water temperature tw is adopted. However, instead of this, an outside air temperature is detected and the heat is detected based on the detected outside air temperature. A determination method for determining whether or not the water W1 as a medium is in a risk of freezing may be employed. As a specific determination method for determining whether or not the water W1 as a heat medium is in a risk of freezing, And various methods can be adopted.

The hot water stored in the hot water tub 8 is not limited to the hot water discharged from the bath tub, but may be any hot water having a heat available for preventing freezing, for example, discharged from a dishwasher. Various things such as hot water can be used.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a system.

FIG. 2 is a flowchart of freeze prevention control;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Target building 3 Heat pump device 3b Heat absorption part 4 Buried heat exchanger 7 Hot water tank 8 Drain tank W1 Heat medium 10B, Pb, Va, Vb, 15, 12 Freezing prevention means

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Tadao Kumada 6-9-9 Koyocho, Higashinada-ku, Kobe City, Hyogo Prefecture Kobe International Housing Co., Ltd.

Claims (3)

[Claims] An underground heat exchanger that circulates the heat medium between a buried heat exchanger for exchanging heat medium with the ground and a heat absorbing portion of the heat pump device, and heats the target building by the heat generated by the heat pump device. It is a heat utilization heat pump system, wherein water is used as the heat medium, and a drain tank for storing waste water generated in the target building is provided, and whether or not the water as the heat medium is in a freezing danger state is determined. Determining, based on the determination result, when water as the heat medium is in a danger of freezing, a freeze prevention means for automatically heating the water as the heat medium using the retained heat of the stored waste water in the drain tank. Geothermal heat pump system provided. 2. A hot water supply tank for storing hot water used in the target building is provided, and the anti-freezing means determines whether or not the retained heat of the stored hot water in the drainage tank is less than a set lower limit. Based on the determination result, in a situation where the water as the heat medium is in a danger of freezing, when the retained heat of the stored drainage in the drainage tank is equal to or greater than a set lower limit, the stored temperature of the stored drainage in the drainage tank is determined. The water as the heat medium is automatically heated by using, and, in a situation where the water as the heat medium is in a danger of freezing, when the retained heat of the stored and discharged hot water in the water discharge tank is less than a set lower limit, the hot water supply is performed. 2. The underground heat utilization heat pump system according to claim 1, wherein water as the heat medium is automatically heated by using the retained heat of the stored hot water in a tank. 3. An underground where the heat medium is circulated between a buried heat exchanger for exchanging a heat medium with the ground and a heat absorbing portion of the heat pump device, and the target building is heated by the heat generated by the heat pump device. A heat utilization heat pump system, wherein water is used as the heat medium, and a hot water supply tank for storing hot water used in the target building is provided, and whether the water as the heat medium is in a freezing danger state is determined. Determining, based on the result of the determination, providing an anti-freezing means for automatically heating the water as the heat medium using the retained heat of the stored hot water in the hot water supply tank when the water as the heat medium is in a danger of freezing. Geothermal heat pump system.