JP2015124918A - Geothermal heat pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a geothermal heat pump device which, even when failure occurs in a compressor or in an expansion valve, operates one of outdoor units and enables operation as an air conditioner.SOLUTION: A geothermal heat pump device includes: a first refrigerant gas circulation passage 13 going through a first compressor 11 and a first expansion valve 12; an outdoor unit 10 for geothermal heat having a heat exchanger 14 for geothermal heat for performing heat exchange between the refrigerant gas which circulates in the first refrigerant gas circulation passage 13 and the geothermal heat; a second refrigerant gas circulation passage 23 going through a second compressor 21 and a second expansion valve 22; an outdoor unit 20 for air heat having a heat exchanger 24 for air heat for performing heat exchange between the refrigerant gas which circulates in the second refrigerant gas circulation passage 23 and the air heat; and an indoor unit 30 for utilizing the heat obtained in the refrigerant gas which circulates in the first refrigerant gas circulation passage 13 in the outdoor unit 10 for geothermal heat and the heat obtained in the refrigerant gas which circulates in the second refrigerant gas circulation passage 23 in the outdoor unit 20 for air heat by a common heating medium.

Description

  The present invention relates to a geothermal heat pump device that collects geothermal heat and uses it for air conditioning and the like.

  A ground heat heat pump device converts ground heat extracted by a heat exchanger embedded in the ground into heat in a necessary temperature range by a heat pump and uses it for air conditioning and hot water supply. The heat exchanger for extracting heat from the ground embeds a resin tube in the ground, circulates a fluid (using antifreeze or the like) as a heat medium, and extracts the ground heat by the fluid. The construction of the heat exchanger is performed by excavating a hole called a bore hole in the ground, inserting a tube into the hole, and finally embedding the tube.

  At a depth of 10m or more in the ground, the temperature becomes almost uniform throughout the year (15-18 ° C). Compared to the open air, it is cold in summer and warm in winter. The geothermal heat pump device uses geothermal heat, which is a renewable energy having the above characteristics.

  On the other hand, an air heat heat pump device (electric heat pump device) widely used for air conditioning is one that takes out heat from the outside air by heat exchange and uses it. In the winter, heat is taken out from the outside air at about 0 ° C. or lower. In summer, heat is extracted from the outside air at 30 ° C or higher.

Therefore, in the winter, the geothermal heat pump device uses ground heat of 15 to 18 ° C., which is warmer than the outside air that can be 0 ° C. or less, for heating. Further, in the summer, the geothermal heat pump device uses ground heat of 15 to 18 ° C., which is cooler than the outside air that can be 30 ° C. or more, for cooling. Thus, it is said that the geothermal heat pump device has higher energy efficiency than the air heat heat pump device, and the running cost is about half. Therefore, the geothermal heat pump device is an ecological system that consumes less energy and has a lower environmental load than the air heat heat pump device.

JP 2006-125814 A JP 2008-275214 A JP 2006-284022 A JP 2009-250555 A JP 2009-276029 A JP 2010-216783 A

  As described above, it is difficult to say that the geothermal heat pump device is generally popular despite the great merit in terms of running cost and global environment. One of the reasons is that the initial cost is excessive.

  That is, in order to collect underground heat, a tube for heat exchange (generally referred to as U-tube) is buried in the ground, and a fluid serving as a heat medium such as antifreeze is circulated in the U-tube, Exchanges heat between the antifreeze and the ground. The depth of the bore hole for sufficiently exchanging heat is required to be at least 10 m, generally about 70 to 80 m to 150 m. Expenses for excavating this borehole are expensive, and in particular increase the initial cost. Along with this, the energy, labor, and post-maintenance required for excavation work also increase costs.

  An example of a specific excavation cost is currently about 8 to 15,000 yen / m. For example, it takes 800 to 1,500,000 yen to dig one borehole with a depth of 100 m. If this is in half, it will be a huge advantage.

  Here, it is considered to design a necessary borehole in a geothermal heat pump device used for cooling and heating a building. In this case, first, the heat load per unit area of the building is calculated with reference to the lowest temperature and the highest temperature in the area to be installed. At this time, the minimum temperature and the maximum temperature are calculated once every ten or more years, and the safety factor is used for the calculation. The total required borehole length is calculated from this heat load, and the depth and number of boreholes are determined accordingly.

  Furthermore, it is necessary to know to some extent the thermal conductivity in the ground of the excavation area. For accuracy, drill one borehole in advance and conduct a thermal response test in advance to measure the actual thermal conductivity. Using the measured values, the total required borehole length can be calculated accurately.

  However, the thermal response test that involves excavation of a borehole is itself an extremely expensive evaluation method. As an example of a specific test cost, the current cost is about 1 million yen. Therefore, for example, there is no cost merit unless the construction is to excavate a large number of boreholes of about 10 or more. When a thermal response test cannot be performed due to cost reasons, generally a low value of about 30 to 40 W / m is used in consideration of safety.

  The shorter the borehole length, the lower the drilling cost. However, if the total length of the borehole is short, heat exchange between the fluid circulating in the U-tube and the ground is not performed. Therefore, if it is too short, sufficient heat collection is not performed, and the capacity of air conditioning is insufficient.

  In particular, it is necessary to heat and cool the air more intensely in the severe winter season and the intense heat season than in other seasons. During the year, a particularly high air-conditioning capacity is required only during mid-winter and mid-summer. In other words, not much air conditioning capacity is required for most other periods.

  After construction with a marginal design in an attempt to reduce borehole excavation costs, if the amount of heat collected is insufficient and the air conditioning capacity is insufficient, the user may be inconvenienced and complaints or complaints may result. Since it is necessary to avoid such a situation, the borehole is designed with a considerable safety factor in consideration of the above-mentioned severe winter season and extreme heat season. Therefore, in actual construction, the borehole must be excavated so as to have the full length with such a considerable safety factor.

As conventional techniques of the geothermal heat pump device proposed from such a viewpoint, Patent Document 1 (Japanese Patent Laid-Open No. 2006-125814), Patent Document 2 (Japanese Patent Laid-Open No. 2008-275214), Patent Document 3 (Japanese Patent Laid-Open No. 2006-284422). ) Etc. are disclosed.
In these prior arts, a geothermal heat pump device and an air heat pump device are arranged in series, and the air heat heat pump device compensates for heat collection that is insufficient with the geothermal heat pump device alone. As a result, even if the depth and number of boreholes are reduced from the theoretical value, sufficient heat collection is attempted.

Patent Document 4 (Japanese Patent Laid-Open No. 2009-250555), Patent Document 5 (Japanese Patent Laid-Open No. 2009-276029), Patent Document 6 (Japanese Patent Laid-Open No. 2010-216783), and the like are also disclosed.
In these conventional techniques, a geothermal heat pump device and an air heat heat pump device are arranged in parallel, and are switched and operated as necessary. These are intended to prevent deterioration in the coefficient of performance (COP) in the geothermal heat pump device.

However, all of those described in Patent Documents 1 to 3 are provided with one path for circulating the refrigerant gas to a pair of compressors and expansion valves. And in the middle of this path, a geothermal outdoor unit that exchanges heat with underground heat and a geothermal outdoor unit that exchanges heat with air heat are arranged in series.
For this reason, when trouble occurs in either the compressor or the expansion valve, it does not operate as a geothermal heat pump device, does not operate as an air heat heat pump device, and does not function as an air conditioner at all.

In addition, all of those described in Patent Documents 4 to 6 are provided with two paths for circulating the refrigerant gas to a pair of compressors and expansion valves. A ground heat outdoor unit that exchanges heat with ground heat is arranged on one path, and a ground heat outdoor unit that exchanges heat with air heat is arranged on the other side. As a result, the underground heat outdoor unit and the air heat outdoor unit are switched and operated.
For this reason, when trouble occurs in either the compressor or the expansion valve, it does not operate as a geothermal heat pump device, does not operate as an air heat heat pump device, and does not function as an air conditioner at all.

  In particular, since the compressor has a large number of moving parts, it is impossible to avoid aging deterioration and breakdown of parts. In addition, it is difficult for the expansion valve to completely avoid problems due to clogging of foreign matter. Thus, the compressor and the expansion valve cannot completely eliminate the troubles associated with the use over time. In the above prior art, when trouble occurs in the compressor and the expansion valve, it has been a problem that it does not function as an air conditioner at all.

The present invention has been made in order to solve such a problem, and can control air conditioning performance in a severe winter season or an extremely hot season while suppressing the drilling cost of the borehole. Further, the present invention can be applied to either a compressor or an expansion valve. Even if a trouble occurs and either the underground heat outdoor unit or the air heat outdoor unit stops, a ground heat heat pump device that can be operated as an air conditioner within the range where the other outdoor unit can collect heat is provided. The purpose is to provide.

In order to achieve the above object, a geothermal heat pump device according to the present invention circulates through a first refrigerant gas circulation path passing through a first compressor and a first expansion valve, and the first refrigerant gas circulation path. An outdoor unit for underground heat having a heat exchanger for underground heat that exchanges heat between refrigerant gas and underground heat,
For air heat that exchanges heat between the second refrigerant gas circulation path that passes through the second compressor and the second expansion valve, and the refrigerant gas circulating through the second refrigerant gas circulation path and the air heat An outdoor unit for air heat having a heat exchanger of
The heat collected in the refrigerant gas circulating in the first refrigerant gas circulation path in the underground heat outdoor unit and the refrigerant gas circulating in the second refrigerant gas circulation path in the air heat outdoor unit The gist is that it includes an indoor unit that uses heat by a common heat medium.

The present invention provides a geothermal outdoor unit having a first refrigerant gas circulation path that passes through a first compressor and a first expansion valve, a second compressor and a second expansion valve that pass through the second expansion valve. An air heat outdoor unit having two refrigerant gas circulation paths is provided.
For this reason, in the underground heat outdoor unit, the overall length of the bore hole for collecting the underground heat can be shortened. As a result, when the output of the outdoor unit for underground heat is insufficient in the severe winter season or the extreme hot season, the outdoor unit for air heat compensates for the shortage. Therefore, it is possible to construct a comfortable air-conditioning system that ensures air-conditioning performance in the severe winter and extreme heat periods while suppressing a great initial cost of drilling the borehole. As described above, the outdoor unit for underground heat is always operated, and the outdoor unit for air heat is operated in an auxiliary manner in a severe winter season or an extremely hot season. At this time, both the underground heat outdoor unit and the air heat outdoor unit can be operated in parallel. Therefore, since it is only necessary to operate the underground heat outdoor unit using the ground heat and operate the air heat outdoor unit as an auxiliary, there is a great merit in running cost.
Further, the heat collected in the refrigerant gas circulating in the first refrigerant gas circulation path in the underground heat outdoor unit and the refrigerant gas circulating in the second refrigerant gas circulation path in the outdoor air heat unit are collected. And an indoor unit that uses the generated heat by a common heat medium.
For this reason, when trouble occurs in the first compressor or the first expansion valve constituting the underground heat outdoor unit and the underground heat outdoor unit stops, the air heat outdoor unit is operated to perform air conditioning. Can be operated. Or, when trouble occurs in the second compressor or the second expansion valve constituting the air heat outdoor unit and the air heat outdoor unit stops, the underground heat outdoor unit is operated to operate the air conditioner. Can be made. Thus, even if trouble occurs in either the compressor or the expansion valve and either the underground heat outdoor unit or the air heat outdoor unit stops, air conditioning is performed within the range in which the other outdoor unit can collect heat. It becomes possible to operate as a machine.

In the present invention, the heat exchanger for underground heat exchanges heat between the refrigerant gas circulating in the first refrigerant gas circulation path and the antifreeze liquid circulating in the circulation pipe buried in the ground. If
The borehole drilled when the antifreeze circulation pipe is buried in the ground can be shortened. As a result, when the output of the outdoor unit for underground heat is insufficient in the severe winter season or the extreme hot season, the outdoor unit for air heat compensates for the shortage. Therefore, it is possible to secure the air conditioning performance in the severe winter season and the extreme heat season while suppressing the drilling cost of the borehole.

In the present invention, the common heat medium for utilizing heat in the indoor unit is antifreeze,
The indoor unit circulation path for circulating the antifreeze liquid, which is the common heat medium, includes a first heat exchanger that exchanges heat with the first refrigerant gas circulation path of the underground heat outdoor unit, and air heat. When a second heat exchanger that exchanges heat with the second refrigerant gas circulation path of the outdoor unit is disposed,
By using an antifreeze liquid as a common heat medium for utilizing heat in the indoor unit, a structure of a geothermal heat pump device that generally uses the antifreeze liquid as the heat medium of the indoor unit can be used as it is. That is, in the underground heat pump devices that are generally distributed in the market, many antifreeze liquids are used as a heat medium for indoor units, so that the structure can be used as it is. Therefore, the cost can be reduced by diverting the structures distributed in the market.

In the present invention, the common heat medium for using heat in the indoor unit is a refrigerant gas,
The indoor unit circulation path for circulating the refrigerant gas that is the common heat medium includes the refrigerant gas that circulates through the first refrigerant gas circulation path of the underground heat outdoor unit, and the second of the air heat outdoor unit. When the refrigerant gas circulating through the refrigerant gas circulation path is circulated,
By using a refrigerant gas as a common heat medium for utilizing heat in the indoor unit, the indoor unit circulation path includes a refrigerant gas circulating in the first refrigerant gas circulation path of the underground heat outdoor unit and Since the refrigerant gas circulating in the second refrigerant gas circulation path of the air heat outdoor unit may be connected and circulated as it is, the cost can be reduced by saving the structure such as the heat exchanger. it can.

It is a lineblock diagram showing a 1st embodiment of a geothermal heat pump device to which the present invention is applied. It is a block diagram which shows 2nd Embodiment of the geothermal heat pump apparatus to which this invention is applied.

  Next, the best mode for carrying out the present invention will be described.

First Embodiment FIG. 1 is a diagram showing a first embodiment of a geothermal heat pump device to which the present invention is applied.

[Overall configuration]
The ground heat heat pump device includes a ground heat outdoor unit 10, an air heat outdoor unit 20, and an indoor unit 30.

  The underground heat outdoor unit 10 and the air heat outdoor unit 20 are each thermally connected to the indoor unit 30 by an indoor unit circulation path 31 that circulates a common heat medium. The indoor unit circulation path 31 includes an underground heat side circulation path 31A thermally connected to the underground heat outdoor unit 10 and air thermally connected to the air heat outdoor unit 20. The heat-side circulation path 31 </ b> B, the underground heat-side circulation path 31 </ b> A, and the air-heat-side circulation path 31 </ b> B merge and are configured by a common circulation path 31 </ b> C that is thermally connected to the indoor unit 30.

  In this example, an antifreeze liquid is circulated in the indoor unit circulation path 31 as a common heat medium for using heat in the indoor unit 30. As said antifreeze, what added the anti-corrosion agent, the antifoamer, etc. as needed by using ethylene glycol as a main component can be used, for example.

[Configuration of underground heat outdoor unit]
The underground heat outdoor unit 10 includes a first refrigerant gas circulation path 13 that passes through a first compressor 11 and a first expansion valve 12, and a refrigerant gas that circulates in the first refrigerant gas circulation path 13. It has a heat exchanger 14 for underground heat that exchanges heat with the underground heat.

  A refrigerant gas is circulated through the first refrigerant gas circulation path 13. As the refrigerant gas, a gas is used that is liquefied by being compressed by the first compressor 11 and cooled by heat exchange, and vaporized by expanding the liquid by the first expansion valve 12. Specifically, various refrigerant gases such as chloro-fluoro-carbon, hydro-chlorofluoro-carbon, hydro-fluoro-carbon, and the like can be used.

  The first refrigerant gas circulation path 13 is provided with a first heat exchanger 32 that performs heat exchange indoors and a heat exchanger 14 for underground heat that performs heat exchange outdoors.

  The heat exchanger 14 for underground heat performs heat exchange between the refrigerant gas circulating in the first refrigerant gas circulation path 13 and the underground heat. A circulation pipe 15 for circulating antifreeze liquid by a first pump 17 is connected to the heat exchanger 14 for underground heat. The circulation pipe 15 is inserted into the borehole 16 excavated in the ground and buried in the ground, and performs heat exchange between the antifreeze liquid circulating in the circulation pipe 15 and the underground heat. As said antifreeze, what added the anti-corrosion agent, the antifoamer, etc. as needed by using ethylene glycol as a main component can be used, for example.

  The heat exchanger 14 for underground heat exchanges heat between the refrigerant gas circulating in the first refrigerant gas circulation path 13 and the antifreeze liquid circulating in the circulation pipe 15 embedded in the ground.

  The first heat exchanger 32 exchanges heat between the antifreeze liquid that is a common heat medium circulating in the indoor unit circulation path 31 and the first refrigerant gas circulation path 13 of the underground heat outdoor unit 10. I do.

  In the underground heat outdoor unit 10, when the refrigerant gas is circulated, the refrigerant gas is compressed by the first compressor 11, liquefied by being cooled by heat exchange, and the liquid is first expanded. Vaporization is achieved by expanding the valve 12. The cycle in which the vaporized refrigerant gas is compressed by the first compressor 11 again is repeated.

  When performing the cooling operation, the refrigerant gas is circulated counterclockwise (in the direction of arrow C). At this time, the refrigerant gas is compressed and heated by the first compressor 11 and is heat-exchanged with the underground heat by the heat exchanger 14 for underground heat to release the heat into the ground and cooled. Liquefaction. The liquid is vaporized by being expanded by the first expansion valve 12 to be cooled, and the heat is exchanged with the antifreeze liquid that is a common heat medium circulating in the indoor unit circulation path 31 by the first heat exchanger 32. To do. Thus, the heat collected in the antifreeze that is a common heat medium circulating in the indoor unit circulation path 31 is used for cooling in the indoor unit 30.

  When performing the heating operation, the refrigerant gas is circulated in the clockwise direction (in the direction of arrow H) as shown. At this time, the refrigerant gas is compressed by the first compressor 11 and heated. This heat is heat-exchanged with the antifreeze liquid which is a common heat medium circulating in the indoor unit circulation path 31 by the first heat exchanger 32. Thus, the heat collected in the antifreeze that is a common heat medium circulating in the indoor unit circulation path 31 is used for heating in the indoor unit 30. The refrigerant gas that has undergone heat exchange in the first heat exchanger 32 is vaporized and cooled by being expanded by the first expansion valve 12, and the cold heat is grounded by the heat exchanger 14 for underground heat. The heat is exchanged with the earth and discharged into the ground.

[Configuration of outdoor unit for air heat]
The outdoor unit for air heat 20 includes a second refrigerant gas circulation path 23 that passes through a second compressor 21 and a second expansion valve 22, and a refrigerant gas that circulates in the second refrigerant gas circulation path 23. It has a heat exchanger 24 for air heat that exchanges heat with air heat.

  A refrigerant gas is circulated through the second refrigerant gas circulation path 23. As the refrigerant gas, a gas is used which is liquefied by being compressed by the second compressor 21 and cooled by heat exchange, and is vaporized by expanding the liquid with a second expansion valve. Specifically, various refrigerant gases such as chloro-fluoro-carbon, hydro-chlorofluoro-carbon, hydro-fluoro-carbon, and the like can be used.

  In the second refrigerant gas circulation path 23, a second heat exchanger 33 that performs heat exchange on the indoor side and a heat exchanger 24 for air heat that performs heat exchange on the outdoor side are disposed.

  The heat exchanger 24 for air heat performs heat exchange between the refrigerant gas circulating in the second refrigerant gas circulation path 23 and air heat. The air heat heat exchanger 24 is provided with a fan 25 that forcibly sends outside air to promote heat exchange. Outside air is blown by the fan 25, and heat exchange is performed between the air heat of the blown outside air and the refrigerant gas circulating in the second refrigerant gas circulation path 23.

  The second heat exchanger 33 exchanges heat between the antifreeze that is a common heat medium circulating in the indoor unit circulation path 31 and the second refrigerant gas circulation path 23 of the air heat outdoor unit 20. Do.

  In the outdoor unit 20 for air heat, when the refrigerant gas is circulated, the refrigerant gas is compressed by the second compressor 21 and liquefied by being cooled by heat exchange, and the liquid is liquefied by the second expansion valve. Vaporize by inflating at 22. The cycle in which the vaporized refrigerant gas is compressed by the second compressor 21 again is repeated.

  When performing the cooling operation, the refrigerant gas is circulated counterclockwise (in the direction of arrow C). At this time, the refrigerant gas is compressed and heated by the second compressor 21, is exchanged with air heat by the heat exchanger 24 for air heat, releases the heat into the air, is cooled, and is liquefied. . The liquid is vaporized by being expanded by the second expansion valve 22 to be cooled, and the cold heat is heat exchanged with the antifreeze liquid which is a common heat medium circulating in the indoor unit circulation path 31 by the second heat exchanger 33. To do. Thus, the heat collected in the antifreeze that is a common heat medium circulating in the indoor unit circulation path 31 is used for cooling in the indoor unit 30.

  When performing the heating operation, the refrigerant gas is circulated in the clockwise direction (in the direction of arrow H) as shown. At this time, the refrigerant gas is compressed by the second compressor 21 and heated. This heat is exchanged by the second heat exchanger 33 with an antifreeze liquid that is a common heat medium circulating in the indoor unit circulation path 31. Thus, the heat collected in the antifreeze that is a common heat medium circulating in the indoor unit circulation path 31 is used for heating in the indoor unit 30. The refrigerant gas that has undergone the heat exchange in the second heat exchanger 33 is vaporized and cooled by being expanded by the second expansion valve 22, and the cold heat is converted into air heat and heat by the heat exchanger 24 for air heat. Replace and release into the air.

  The second compressor 21 in the outdoor unit 20 for air heat may be operated with general electric power, or may be operated with electric power generated by a gas engine and a generator (not shown).

[Configuration of indoor unit]
The indoor unit 30 includes the heat collected in the refrigerant gas circulating in the first refrigerant gas circulation path 13 in the underground heat outdoor unit 10, and the second refrigerant gas circulation path in the air heat outdoor unit 20. The heat collected in the refrigerant gas circulating through the heat exchanger 23 is used by a common heat medium.

  In this example, the common heat medium for using heat in the indoor unit 30 is antifreeze. Therefore, as described above, in this example, the antifreeze liquid is circulated in the indoor unit circulation path 31 as a common heat medium for using heat in the indoor unit 30.

  A first heat exchanger 32 that exchanges heat with the first refrigerant gas circulation path 13 of the underground heat outdoor unit 10 is provided in the indoor unit circulation path 31 that circulates the antifreeze liquid that is the common heat medium. And a second heat exchanger 33 for exchanging heat with the second refrigerant gas circulation path 23 of the outdoor unit 20 for air heat.

  The indoor unit circulation path 31 is configured by connecting a ground heat side circulation path 31A, an air heat side circulation path 31B, and a common circulation path 31C.

  The underground heat-side circulation path 31 </ b> A passes through the first heat exchanger 32. Thereby, the above-mentioned underground heat side circulation path 31 </ b> A exchanges heat between the antifreeze liquid circulating inside and the refrigerant gas circulating through the first refrigerant gas circulation path 13 of the underground heat outdoor unit 10. The geothermal side circulation path 31A is provided with a second pump 37 for circulating the antifreeze liquid and a first check valve 35 for preventing the antifreeze backflow.

  The air heat side circulation path 31 </ b> B passes through the second heat exchanger 33. Thereby, the air heat side circulation path 31 </ b> B exchanges heat between the antifreeze liquid circulating inside and the refrigerant gas circulating through the second refrigerant gas circulation path 23 of the outdoor unit 20 for air heat. The air heat side circulation path 31B is provided with a third pump 38 for circulating the antifreeze liquid and a second check valve 36 for preventing a reverse flow of the antifreeze liquid.

  The common circulation path 31 </ b> C allows the antifreeze liquid that is circulated by the ground heat side circulation path 31 </ b> A and the air heat side circulation path 31 </ b> B to pass through the indoor unit 30. Thereby, the heat collected in the antifreeze circulating in the common circulation path 31C is used in the indoor unit 30.

  With such a structure, the heat collected from the ground heat by operating the underground heat outdoor unit 10 is used in the indoor unit 30 via the ground heat side circulation path 31A and the common circulation path 31C. Further, the heat collected from the air heat by operating the air heat outdoor unit 20 is utilized in the indoor unit 30 via the air heat side circulation path 31B and the common circulation path 31C.

  An open / close valve 34 is provided in the air heat side circulation path 31B.

  When the on-off valve 34 is closed, the circulation of the antifreeze liquid circulating in the air heat side circulation path 31B is stopped. In this state, the heat collected from the air heat by operating the air heat outdoor unit 20 is not used by the indoor unit 30. The indoor unit 30 uses the heat collected from the ground heat by operating the underground heat outdoor unit 10 exclusively.

  When the opening / closing valve 34 is opened, the antifreeze circulates in the air heat side circulation path 31B. In this state, the heat collected from the ground heat by operating the underground heat outdoor unit 10 is used in the indoor unit 30, and at the same time, the heat collected from the air heat by operating the outdoor unit 20 for air heat. Is used in the indoor unit 30.

〔control〕
The underground heat outdoor unit 10, the air heat outdoor unit 20, and the indoor unit 30 are controlled by the control means 40, and the underground heat pump device is operated as follows.

  First, as the setting of the operation mode of the indoor unit 30, it is set whether to select the cooling operation mode in summer or the heating operation mode in winter. Next, in each operation mode, the room temperature is set to a desired set temperature.

  In both the cooling operation mode in summer and the heating operation mode in winter, the geothermal outdoor unit 10 is always operated first.

  That is, the control means 40 operates the 1st compressor 11, the 1st pump 17, and the 2nd pump 37, and performs the air-conditioning driving | operation by the outdoor unit 10 for underground heat. At this time, in the cooling operation mode in summer, the first compressor 11 is controlled so that the refrigerant gas circulates in the direction of arrow C through the first refrigerant gas circulation path 13 in the underground heat outdoor unit 10. On the other hand, in the heating operation mode in winter, the first compressor 11 is controlled so that the refrigerant gas circulates in the direction of arrow H through the first refrigerant gas circulation path 13 in the underground heat outdoor unit 10.

  The control means 40 closes the on-off valve 34 when the operation of the underground heat outdoor unit 10 is sufficient to collect heat with respect to the set temperature, and the third pump 38, the second compressor 21 and The fan 25 is stopped and the air heat outdoor unit 20 is stopped.

  The control means 40 opens the on-off valve 34 when the ground heat outdoor unit 10 is in operation to collect heat with respect to the set temperature, and opens the third pump 38, the second compressor 21, and The fan 25 is operated and the air heat outdoor unit 20 is operated.

  That is, the outdoor unit 10 for geothermal heat is always operated, the heat collected from the ground heat is used by the indoor unit 30, and only when it is determined that the heat from the ground heat is insufficient. Then, the operation of the outdoor unit for air heat 20 is started to assist the outdoor unit 10 for underground heat. When it is determined that the heat collection from the ground is sufficient, the operation of the outdoor unit for air heat 20 is automatically stopped, and the operation of only the outdoor unit for underground heat 10 is returned. Thus, the energy related to air conditioning is minimized by always operating the outdoor unit for underground heat 10 as the main.

  Judgment on whether heat sampling from underground heat is sufficient or insufficient can be made as follows.

  First, the control means 40 includes the temperature (T1) of the antifreeze liquid fed from the geothermal outdoor unit 10 to the indoor unit 30 and the temperature (T2) of the antifreeze returned from the geothermal outdoor unit 10 to the ground. And monitor.

And when the said control means 40 is the heating operation mode of winter season, when T1 becomes more than -5-10 ° C of preset temperature, or when T2 becomes -7-10 ° C or less Then, it is determined that heat collection from the underground heat is insufficient, and the operation of the outdoor unit 20 for air heat is started.
Further, the control means 40, when in the cooling operation mode in the summer, when T1 becomes +5 to + 10 ° C or higher of the set temperature, or when T2 becomes +40 to + 50 ° C or higher, It is determined that heat collection from the air is insufficient, and the operation of the outdoor unit 20 for air heat is started.

  In the case of the winter heating operation mode, the temperature (T1) of the antifreeze liquid fed to the indoor unit 30 such as a fan coil generally needs to be 40 ° C to 60 ° C. When the temperature is lower than 40 ° C., the temperature blown from the indoor unit 30 is not felt warmly. On the other hand, if the temperature exceeds 60 ° C., a problem occurs in the internal parts of the indoor unit 30 (particularly, the antifreeze liquid seal portion).

  When the extreme cold season is considered, if the heat collected from the ground becomes insufficient, the temperature of water supplied to the indoor unit 30 cannot be controlled within the set range of 40 to 60 ° C. For example, when set to 45 ° C., water will be fed at 40 ° C. or lower. Therefore, when the set temperature is −5 ° C. to −10 ° C. or higher, it is determined that heat collection is insufficient.

  Even if the set temperature is within the above temperature range, if the temperature (T2) of the antifreeze returned to the ground is -7 ° C to -10 ° C, the soil around the borehole 16 begins to freeze. . When such a situation occurs, it becomes impossible to sufficiently extract heat from the bore hole 16. In the worst case, the entire bore hole 16 is frozen. In order to avoid this, the temperature (T2) of the antifreeze returned to the borehole 16 must also be monitored. The temperature needs to be −7 ° C. to −10 ° C.

  In the case of the cooling operation mode in summer, the temperature (T1) of the antifreeze liquid fed to the indoor unit 30 needs to be 7 ° C to 20 ° C. If it is less than 7 ° C., the temperature is too low and the physical condition may be lost. Moreover, if it becomes less than 7 degreeC, a big load will be applied to the 1st compressor 11, COP will be deteriorated, and the merit which utilizes underground heat will fade. If it exceeds 20 ° C, it does not feel cool. Therefore, the temperature (T1) of the antifreeze liquid fed to the indoor unit 30 is set to 7 ° C to 20 ° C.

  In the extreme heat season, if the heat collected from the ground is insufficient, the temperature (T1) of the antifreeze liquid fed to the indoor unit 30 cannot be controlled to 7 to 20 ° C. When the set temperature is + 5 ° C. to + 10 ° C. or more, it can be determined that the heat collected from the underground heat is insufficient. Moreover, even if it is in said temperature range, when the temperature (T2) of the antifreeze liquid returned to the ground will be 40 to 50 degreeC or more, sufficient cold heat cannot be collected from underground heat. Although the situation of freezing does not occur, it is necessary to monitor the temperature (T2) of the antifreeze liquid returned to the borehole 16 as less than 40 ° C.

  The control means 40 monitors the temperature (T3) of the antifreeze liquid introduced from the circulation pipe 15 into the underground heat outdoor unit 10.

And the said control means 40 judges that the extraction | collection of the heat | fever from underground heat was insufficient when T3 became 0 degrees C or less at the time of the heating operation mode of winter, and the outdoor unit 20 for air heats Start driving.
Further, the control means 40 determines that the heat extraction from the underground heat is insufficient when T3 becomes 35 ° C. or higher in the summer cooling operation mode, and the air heat outdoor unit 20 Start driving.

This is because in the winter heating operation mode, COP gradually decreases as T3 decreases, and COP decreases to approximately 2 when T3 decreases to about 0 ° C.
Similarly, in the cooling operation mode in summer, when T3 increases, COP gradually decreases, and when T3 increases to approximately 35 ° C., COP decreases to approximately 2.

  With the above configuration, in the present embodiment, the borehole 16 is not drilled more than necessary, and the depth of the design that anticipates the safety factor (for example, about 60% of the conventional one) can be reduced, and the drilling cost can be reduced. . In other words, the conventional excavation of about 60% can be covered by the heat collected from geothermal heat for a period of about 90% of the year, and sufficient air conditioning is performed by operating only the geothermal outdoor unit 10. Can do. If the heat collected from the ground cannot keep up with the remaining 10% of the period, the air heat outdoor unit 20 is operated to assist the shortage of the underground heat outdoor unit 10 Sufficient cooling and heating is performed.

  Therefore, an unnecessary cost increase of the borehole 16 is suppressed, and a period during which sufficient cooling / heating cannot be performed only by the underground heat outdoor unit 10 is backed up by the air heat outdoor unit 20 to supplement the shortage. Since the underground heat outdoor unit 10 is operated mainly, there is a great merit in terms of running cost.

[Function and effect]
As described above, the first embodiment has the following effects.

Via the geothermal outdoor unit 10 having the first refrigerant gas circulation path 13 passing through the first compressor 11 and the first expansion valve 12, via the second compressor 21 and the second expansion valve 22 An air heat outdoor unit 20 having a second refrigerant gas circulation path 23 is provided.
For this reason, in the underground heat outdoor unit 10, the overall length of the bore hole 16 for collecting underground heat can be shortened. As a result, when the output of the underground heat outdoor unit 10 is insufficient in the severe winter season or the extreme heat season, the air heat outdoor unit 20 compensates for the shortage. Therefore, it is possible to construct a comfortable air-conditioning system that ensures air-conditioning performance in the severe winter season and the hot summer season while suppressing a great initial cost of the drilling cost of the bore hole 16. As described above, the underground heat outdoor unit 10 is always operated, and the air heat outdoor unit 20 is operated in an auxiliary manner in a severe winter season or a hot summer season. At this time, both the underground heat outdoor unit 10 and the air heat outdoor unit 20 can be operated in parallel. Therefore, since it is only necessary to operate the underground heat outdoor unit 10 using the ground heat and operate the air heat outdoor unit 20 as an auxiliary, there is a great merit in running cost.
Further, the heat collected in the refrigerant gas circulating in the first refrigerant gas circulation path 13 in the underground heat outdoor unit 10 and the second refrigerant gas circulation path 23 in the air heat outdoor unit 20 are circulated. And an indoor unit 30 that uses the heat collected in the refrigerant gas by a common heat medium.
For this reason, when trouble occurs in the first compressor 11 or the first expansion valve 12 constituting the geothermal outdoor unit 10 and the geothermal outdoor unit 10 is stopped, the outdoor unit 20 for air heat is used. The air conditioning can be operated by operating. Alternatively, when trouble occurs in the second compressor 21 or the second expansion valve 22 constituting the air heat outdoor unit 20 and the air heat outdoor unit 20 is stopped, the underground heat outdoor unit 10 is operated. The air conditioning can be operated. As described above, even if trouble occurs in either the compressor or the expansion valve and either the underground heat outdoor unit 10 or the air heat outdoor unit 20 is stopped, the other outdoor unit is within the range where heat can be collected. It can be operated as an air conditioner.

The heat exchanger 14 for underground heat exchanges heat between the refrigerant gas that circulates in the first refrigerant gas circulation path 13 and the antifreeze liquid that circulates in the circulation pipe 15 embedded in the ground. Because there is
The total length of the bore hole 16 excavated when the antifreeze circulation pipe 15 is buried in the ground can be shortened. As a result, when the output of the underground heat outdoor unit 10 is insufficient in the severe winter season or the extreme heat season, the air heat outdoor unit 20 compensates for the shortage. Therefore, it is possible to secure air conditioning performance in the severe winter season or the extreme heat season while suppressing the drilling cost of the bore hole 16.

A common heat medium for using heat in the indoor unit 30 is antifreeze,
A first heat exchanger 32 that exchanges heat with the first refrigerant gas circulation path 13 of the underground heat outdoor unit 10 is provided in the indoor unit circulation path 31 that circulates the antifreeze liquid that is the common heat medium. And the second heat exchanger 33 for exchanging heat with the second refrigerant gas circulation path 23 of the outdoor unit 20 for air heat,
By using a common heat medium for utilizing heat in the indoor unit 30 as the antifreeze liquid, the structure of the underground heat pump device that generally uses the antifreeze liquid as the heat medium of the indoor unit 30 can be used as it is. That is, in the geothermal heat pump devices that are generally distributed in the market, since many antifreeze liquids are used as the heat medium for the indoor unit 30, the structure can be used as it is. Therefore, the cost can be reduced by diverting the structures distributed in the market.

Second Embodiment FIG. 2 shows a second embodiment of the present invention.

〔Constitution〕
In this example, the common heat medium for using heat in the indoor unit 30 is refrigerant gas.

  That is, the refrigerant gas is circulated through the indoor unit circulation path 31. As the refrigerant gas, a gas is used which is liquefied by being compressed by a compressor and cooled by heat exchange, and vaporized by expanding the liquid with an expansion valve. Specifically, various refrigerant gases such as chloro-fluoro-carbon, hydro-chlorofluoro-carbon, hydro-fluoro-carbon, and the like can be used.

  In this example, the indoor unit circulation path 31 that circulates the refrigerant gas that is the common heat medium includes a refrigerant gas that circulates through the first refrigerant gas circulation path 13 of the underground heat outdoor unit 10, and air heat. The refrigerant gas circulating through the second refrigerant gas circulation path 23 of the outdoor unit 20 is circulated.

  That is, in this example, the first refrigerant gas circulation path 13 of the underground heat outdoor unit 10 and the underground heat side circulation path 31A are directly connected to each other. Thereby, the refrigerant gas which circulates through the first refrigerant gas circulation path 13 of the underground heat outdoor unit 10 is circulated directly to the common circulation path 31C via the underground heat side circulation path 31A.

  In this example, the second refrigerant gas circulation path 23 of the air heat outdoor unit 20 and the air heat side circulation path 31B are directly connected to each other. Thereby, the refrigerant gas circulating through the second refrigerant gas circulation path 23 of the outdoor unit 20 for air heat is circulated directly to the common circulation path 31C via the air heat side circulation path 31B.

  In this example, the geothermal heat circuit 31A is not provided with the second pump 37 for circulating the antifreeze liquid and the first check valve 35 for preventing the antifreeze backflow. Further, the air heat side circulation path 31B is not provided with a third pump 38 for circulating the antifreeze liquid and a second check valve 36 for preventing a reverse flow of the antifreeze liquid.

[Function and effect]
The second embodiment is the same as the first embodiment except that the common heat medium for utilizing heat in the indoor unit 30 is a refrigerant gas. Therefore, the same reference numerals are given to the same parts as those in the first embodiment. In the second embodiment, since the common heat medium for using heat in the indoor unit 30 is only the refrigerant gas, basically the same operational effects as the first embodiment are achieved. .

In the second embodiment, the common heat medium for using heat in the indoor unit 30 is a refrigerant gas,
The indoor unit circulation path 31 that circulates the refrigerant gas that is the common heat medium includes the refrigerant gas that circulates through the first refrigerant gas circulation path 13 of the underground heat outdoor unit 10 and the air heat outdoor unit 20. Since the refrigerant gas circulating in the second refrigerant gas circulation path 23 is circulated,
By using a common heat medium for utilizing heat in the indoor unit 30 as a refrigerant gas, the indoor unit circulation path 31 is circulated through the first refrigerant gas circulation path 13 of the underground heat outdoor unit 10. The refrigerant gas to be circulated and the refrigerant gas circulated through the second refrigerant gas circulation path 23 of the outdoor unit 20 for air heat may be connected and circulated as they are, thereby saving a structure such as a heat exchanger. Cost can be reduced.

10: Outdoor unit for geothermal heat 11: First compressor 12: First expansion valve 13: First refrigerant gas circulation path 14: Heat exchanger 15 for geothermal heat: Circulation pipe 16: Bore hole 17: First pump 20: outdoor unit for air heat 21: second compressor 22: second expansion valve 23: second refrigerant gas circulation path 24: heat exchanger for air heat 25: fan 30: indoor unit 31: Indoor unit circulation path 31A: Geothermal side circulation path 31B: Air heat side circulation path 31C: Common circulation path 32: First heat exchanger 33: Second heat exchanger 34: On-off valve 35: First 1 check valve 36: second check valve 37: second pump 38: third pump 40: control means

Claims (4)

Underground exchanging heat between the first refrigerant gas circulation path that passes through the first compressor and the first expansion valve, and the refrigerant gas circulating in the first refrigerant gas circulation path and the underground heat A geothermal outdoor unit having a heat exchanger for heat;
For air heat that exchanges heat between the second refrigerant gas circulation path that passes through the second compressor and the second expansion valve, and the refrigerant gas circulating through the second refrigerant gas circulation path and the air heat An outdoor unit for air heat having a heat exchanger of
The heat collected in the refrigerant gas circulating in the first refrigerant gas circulation path in the underground heat outdoor unit and the refrigerant gas circulating in the second refrigerant gas circulation path in the air heat outdoor unit A geothermal heat pump device comprising an indoor unit that uses heat by a common heat medium. The heat exchanger for underground heat performs heat exchange between a refrigerant gas circulating in the first refrigerant gas circulation path and an antifreeze liquid circulating in a circulation pipe embedded in the ground. The geothermal heat pump device according to 1. The common heat medium for using heat in the indoor unit is antifreeze,
The indoor unit circulation path for circulating the antifreeze liquid, which is the common heat medium, includes a first heat exchanger that exchanges heat with the first refrigerant gas circulation path of the underground heat outdoor unit, and air heat. The geothermal heat pump device according to claim 1 or 2, wherein a second heat exchanger that exchanges heat with the second refrigerant gas circulation path of the outdoor unit is disposed. A common heat medium for using heat in the indoor unit is refrigerant gas,
The indoor unit circulation path for circulating the refrigerant gas that is the common heat medium includes the refrigerant gas that circulates through the first refrigerant gas circulation path of the underground heat outdoor unit, and the second of the air heat outdoor unit. The geothermal heat pump device according to claim 1 or 2, wherein the refrigerant gas circulating in the refrigerant gas circulation path is circulated.

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