JP2013190202A - Geothermal heat utilizing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioning heat source device excellent in energy saving, electric power load levelling, and system extensibility, while preventing a large change of the soil temperature in geothermal heat utilization, making an antifreeze solution unnecessary, miniaturizing a geothermal heat exchange coil, and reducing a cost of construction.SOLUTION: In a geothermal heat utilizing device comprising air conditioning devices (2, 2A, and 2B), a heat medium supplied to the air conditioning devices, a geothermal heat exchanger (4) which performs heat exchange between the heat medium thereof and soil, and a heat source mechanism (3) capable of heating or cooling the heat medium, in which the heat source mechanism (3) has a function to cool or heat the heat medium such that the soil temperature ranges in a predetermined temperature span, the air conditioning devices (2, 2A, and 2B), the heat source mechanism (3), and the geothermal heat exchanger (4) use a single heat medium mutually.

Description

  The present invention relates to a geothermal heat utilization device (for example, a geothermal heat utilization heat pump system) that uses geothermal heat as a heat source.

The earth has a large heat storage capacity, the underground temperature is stable regardless of the season, and the soil temperature is said to be close to the average temperature of the region regardless of the season in the underground 5-10 m. For example, it is 16-17 ° C around Tokyo, so if it is used as a heat source for a heat pump, it is superior to the atmosphere as a heat collection (heat collection) source for heating and as a heat radiation source for cooling, more than the “air heat source heat pump” The coefficient of performance (COP) is likely to be high.
Such a technique is called a “soil heat source heat pump” or a “geothermal heat pump”, and is attracting attention as an energy-saving technique in the future. Furthermore, in Japan, it is also expected as a technology to mitigate urban heat island phenomenon.

However, in the conventional geothermal heat pump, as the air conditioning operation is continued for several weeks to several months, in the heat collection (heating) operation, the soil temperature gradually decreases as shown in FIGS. In operation, the soil temperature gradually increases as shown in FIGS. For this reason, the heat collection capacity and the heat radiation capacity are insufficient, and the heating COP and the cooling COP tend to decrease.
Here, the symbol δ in FIG. 17 indicates the amount of decrease in soil temperature that occurs in one day. And the code | symbol (delta) in FIG. 19 has shown the raise amount of the soil temperature which arises in one day.

17 and 19, the horizontal axis indicates the elapsed time (24 hours per day), the vertical axis indicates the soil temperature, and the soil temperature for 4 days during heating (FIG. 17) or cooling (FIG. 19). It shows a change.
18 and 20, the elapsed time from the start of heating (FIG. 18) or the start of cooling (FIG. 20) is a scale on the horizontal axis, the temperature of the soil is plotted on the vertical axis, and the soil condition in the 12 days from the start of heating or the start of cooling. It shows the temperature change.

In particular, in the operation of collecting heat from the soil during heating operation, the circulating water temperature to the underground heat exchanger is lowered, so that it is necessary to use an antifreeze liquid to which ethylene glycol, propylene glycol or the like is added in order to prevent freezing. Glycols have the effect of increasing the viscosity of the circulating water, and therefore have the disadvantage of increasing the power of the circulating pump and decreasing the heat transfer rate in heat exchange. In addition, when the antifreeze leaks, the soil is contaminated.
It should be noted that freezing of the circulating water as the heat medium occurs mainly on the water side of the refrigerant evaporator, and the expansion of water due to freezing damages the heat exchanger.
On the other hand, in the cooling heat radiation operation, the soil temperature rises as the operation time elapses, and thus a phenomenon in which the COP is lower than that of the air heat source heat pump is observed.

In addition to the above-described problems, the geothermal heat pump has the following problems.
(1) The installation area of the underground heat exchanger is large and the cost is high.
(2) The soil temperature will be altered over the long term.
(3) The energy saving effect is insufficient compared to the air heat source heat pump.
(4) It is desirable to support power load leveling (use of nighttime power), but this is not always possible.

The problem (1) is due to the necessity to cover the borehole ground heat exchanger with a wide space (preferably a space of 5 m or more) because it is necessary to cover the heat source during the heating and cooling period for several months with soil heat. doing. And this problem (1) causes the excavation cost of the borehole to rise.
The problem (2) is caused by the fact that the geothermal heat does not sufficiently recover due to the imbalance between the heat collection amount in the heating operation and the heat release amount in the cooling operation. For example, if the amount of heat collected for heating is greater than the amount of heat dissipated for cooling, it will not rise to the original ground temperature at the start of cooling the next year. Conversely, if the amount of heat dissipated by cooling is greater than the amount of heat collected by heating, the temperature will not drop to the original ground temperature at the start of cooling the next year.
This problem is potential while the number of applications of geothermal heat pumps is small, but it may become apparent as the spread of geothermal heat pumps increases and the density of underground heat exchangers increases. .

As described in the problem (3), in the heat pump that uses geothermal heat, even if a heat condition that is more advantageous than the air heat pump can be obtained at the beginning of the operation, Since the soil temperature gradually decreases (see FIG. 18), the refrigerant evaporation temperature of the heat pump decreases, and the heating capacity and COP decrease. Similarly, in the case of the cooling and heat radiation exercise, the soil temperature gradually increases as the number of days elapses from the start of operation (see FIG. 20), and the COP decreases because the refrigerant evaporation temperature of the heat pump increases.
The problem (4) is not a problem inherent to the underground heat-utilizing heat pump, but is an inevitable requirement for an air-conditioning heat source apparatus that uses electric power.

As another conventional technique, as shown in FIG. 21, when the temperature of the heat medium W1 is lowered to the freezing temperature, a technique for heating the heat medium W1 using the hot water Qb discharged from the bathtub or the like has been proposed. (Patent Document 1).
However, in the related art (Patent Document 1), when the discharged hot water Qb from the bathtub cannot be used at all times, the installation area and cost of the underground heat exchanger 4 cannot be reduced.
In addition, since cooling is not taken into consideration, heat balance cannot be achieved when performing cooling operation.
Furthermore, there is a problem that it is impossible to meet the demand for power load leveling.

As another conventional technique, as shown in FIG. 22, the heat pump 1H is operated in a reverse cycle in a time zone in which the cooling / heating operation is not performed and the electricity usage fee is low, and the underground heat exchange is performed. A technique has been proposed in which heat is applied to the vessel 2H side to recover the underground heat temperature (Patent Document 2).
However, in this prior art (Patent Document 2), when the underground temperature has decreased too much as a result of the heating operation other than the time period when the electricity usage fee is low, or as a result of the cooling operation, the underground temperature has increased too much. In such a case, it is impossible to cope with the problem that the heat collection capacity and COP of the heating operation and the COP of the cooling operation are lowered.
Further, since antifreeze (brine) is required, there is a risk of soil contamination due to leakage of the antifreeze.

As another prior art, as shown in FIG. 23, a heat exchanger 3H of underground heat exchanger 11H and air (outside air) is arranged in series, and most of the condensation heat of the gas-phase refrigerant is outside air. There is a technique for discharging the sensible heat of the liquid-phase refrigerant into the ground, thereby improving the cooling capacity and reducing the size of the underground heat exchanger (Patent Document 3).
However, the related art (Patent Document 3) has a problem that the operation cost increases because the regeneration operation cannot be performed using a time zone in which the electricity usage fee is low.
Moreover, when heating, antifreeze (brine) is required.

JP-A-11-94367 JP 2005-48972 A JP 2006-284022 A

  The present invention has been proposed in order to solve the above-described problems of the prior art, and can prevent a situation in which the underground temperature fluctuates significantly as a result of the air-conditioning operation. It is possible to cope with the case where the COP for heating operation and COP for cooling operation decrease outside the inexpensive time zone, and it is not necessary to use antifreeze liquid (brine), and it is easy to expand the system using geothermal heat The purpose is to provide a device.

The geothermal heat utilization apparatus (for example, the geothermal heat utilization heat pump system 101, 102) of the present invention is supplied to an air conditioner (for example, an air conditioner heat pump 2, a hot water supply facility 2A, a refrigerator-freezer 2B, etc.) and the air conditioner. Heat medium (for example, circulating water), an underground heat exchanger (4) that performs heat exchange between the heat medium and soil, and a heat source mechanism (for example, heat source heat pump 3) that can cool or heat the heat medium. And the heat source mechanism (3) is a geothermal heat utilization device having a function of cooling or heating the heat medium so that the soil temperature is within a predetermined temperature range.
The air conditioners (2, 2A, 2B), the heat source mechanism (3), and the underground heat exchanger (4) use a single heat medium.
In carrying out the present invention, the soil temperature can be determined by measuring the temperature of the heat medium (for example, circulating water). Alternatively, a temperature sensor may be embedded in the soil and the soil temperature may be directly measured.

 In the geothermal heat utilization device of the present invention (the geothermal heat utilization device of claim 1), the heat source mechanism (3) preferably has a function of operating based on the temperature (TW) of the heat medium.

 And in the geothermal heat utilization apparatus of this invention, it is preferable that the said heat-source mechanism (3) has a function operated by comparing the temperature (TW) of the said heat medium with a threshold value.

 Furthermore, in the geothermal heat utilization apparatus of the present invention, a temperature measuring device (6) for measuring the temperature (TW) of the heat medium is interposed in the vicinity of the outlet (Jo) of the underground heat exchanger (4). Is preferred.

Here, the term “air-conditioning equipment” is intended to include not only heating and cooling heat pumps (air-conditioning heat pumps) but also all equipment that uses heat or cold in the air-conditioned space, such as hot water supply equipment and refrigerator-freezers. It is used.
The term heating operation includes not only heating operation by an air conditioning heat pump but also all operations for supplying heat to an air-conditioned space, such as an operation for operating a hot water supply facility.
Similarly, the term “cooling operation” includes not only the cooling operation by the air conditioning heat pump but also all the operations that take heat from the air-conditioned space, such as the operation of operating a refrigerator-freezer or the like.

  The term “heat source device” includes not only an air heat source heat pump but also a solar heat source heat pump, an absorption chiller / heater, and all other devices having the ability to heat or cool circulating water.

  Furthermore, the geothermal heat utilization apparatus of the present invention communicates with the air conditioner (2) and the air conditioner (2) that supplies heat to the air conditioned space (1) or takes heat away from the air conditioned space (1). And a heat exchanger (ground heat exchanger 4) having a function of exchanging heat with the ground (soil), the air conditioner (2) and the heat exchanger (4) are communicated with each other, and a heat medium is provided inside. A water circulation system (Lw), a heat source device (3) interposed in the piping system (Lw), and an outlet of the heat exchanger (4) of the piping system (Lw). A water temperature measuring device (6) for measuring the temperature of flowing water (ground heat exchanger outlet temperature TW of circulating water) and a control device (5) for controlling the operation of the heat source device (3), The control device (5) is a case where the air conditioner (2) is performing a heating operation, and the water temperature (TW) measured by the water temperature measuring device (6) is the first threshold value. When the temperature becomes lower than the temperatures THD2, THN2) in FIG. 4, the heat source device (3) is operated so as to heat the water flowing through the piping system (Lw), and the heat source device (3) is operated to Is equal to or higher than a second threshold value (temperatures THD1, THN1 in FIG. 4) that is higher than the first threshold value, an operation of heating the water flowing through the piping system (Lw) by the heat source device (3) is performed. In this case, the air conditioner (2) has a function of stopping, and the water temperature (TW) measured by the water temperature measuring device (6) is a fourth threshold value (temperature TCD2, FIG. 4). When the temperature is higher than TCN2), the heat source device (3) is operated so as to cool the water flowing through the piping system (Lw), and the heat source device (3) is operated so that the water temperature is lower than the fourth threshold value. Is lower than the third threshold value (temperatures TCD1, TCN1 in FIG. 4), which is a low temperature, It has a function of stopping the operation of cooling the water flowing through the piping system (Lw) by the source unit (3), and the first threshold value to the fourth threshold value are a time zone where the electricity usage fee is low (for example, It can be set differently between 22:00 to 8:00: nighttime and other time zones (for example, 8:00 to 22:00: daytime).

  And the control method of the geothermal heat utilization apparatus of this invention is connected with the air-conditioning equipment (2) which supplies heat to an air-conditioned space (1), or deprives heat from an air-conditioned space (1), and an air-conditioning equipment (2). The heat exchanger (ground heat exchanger 4) having a function of exchanging heat with the ground (soil), the air conditioner (2), and the heat exchanger (4) are connected to each other and heat is internally generated. In the control method of a heat pump using underground heat having a piping system (Lw) through which water as a medium circulates and a heat source device (3) interposed in the piping system (Lw), heat exchange of the piping system (Lw) The step (S1) of measuring the heat exchanger outlet temperature (TW) of the water flowing through the pipe (Lw) by the water temperature measuring means (6) interposed at the outlet of the vessel (4), and the measured water temperature An operation control step (S5) for controlling the operation of the heat source device (3) based on the (circulated water underground heat exchanger outlet temperature TW). S8, S13, S16), and in the operation control step (S5, S8, S13, S16), the air conditioner (2) is performing the heating operation, and is measured by the water temperature measuring device (6). When the water temperature (TW) is lower than the first threshold (temperatures THD2, THN2 in FIG. 4), the heat source device (3) is operated so as to heat the water flowing through the piping system (Lw). When the heat source device (3) is operated and the water temperature becomes equal to or higher than the second threshold value (temperatures THD1, THN1 in FIG. 4) higher than the first threshold value, the piping system (Lw The water temperature (TW) measured by the water temperature measuring device (6) is the fourth threshold value (Fig. 4 temperature TCD2, TCN2)), the piping system (Lw) flows. The heat source device (3) is operated so as to cool the water to be cooled, the heat source device (3) is operated, and the water temperature is lower than the third threshold (temperatures TCD1, TCN1 in FIG. 4) lower than the fourth threshold. In this case, the operation of cooling the water flowing through the piping system (Lw) by the heat source device (3) is stopped, and the first threshold value to the fourth threshold value are a time zone in which the electricity usage fee is inexpensive (for example, 22 It can be configured so that it is different between the time of 8:00 to 8:00: nighttime nt) and other time zones (for example, 8:00 to 22:00: daytime dt).

  In the geothermal heat utilization device of the present invention, the control device (5) is measured by the water temperature measurement device (6) when performing a cooling operation in a predetermined time zone (for example, from 13:00 to 16:00 in summer). Water flowing through the piping system (Lw) only when the water temperature (TW) is higher than the fifth threshold (temperature TCD4 in FIG. 14) higher than the fourth threshold (temperature TCD2 in FIG. 4). It is possible to have a function of operating the heat source device (3) so as to cool it (FIG. 14).

  Alternatively, in the geothermal heat utilization apparatus of the present invention, the control device (5) is configured so that the heat source device (3) has a piping system (Lw) in a predetermined time zone (for example, from 13:00 to 16:00 in summer). A function of controlling not to perform the operation of cooling the flowing water can be provided (FIGS. 15 and 16).

  In the control method of the geothermal heat utilization apparatus of the present invention, a step (S45, S234) of determining whether or not a predetermined time zone (for example, 13:00 to 16:00 in summer), and cooling in the predetermined time zone When the operation is performed, the water temperature (TW) measured by the water temperature measuring device (6) is higher than the fifth threshold value (temperature TCD4 in FIG. 14) higher than the fourth threshold value (temperature TCD2 in FIG. 4). Only when the temperature is high, the heat source device (3) can be operated to cool the water flowing through the piping system (Lw).

  Alternatively, in the control method of the geothermal heat utilization apparatus of the present invention, a step (S45, S234) of determining whether or not a predetermined time zone (for example, 13:00 to 16:00 in summer) and a predetermined time zone (For example, in the summer, from 13:00 to 16:00), the heat source device (3) can include a step (S10) of controlling so as not to perform the operation of cooling the water flowing through the piping system (Lw).

According to the present invention having the above-described configuration, an air conditioner (for example, an air conditioning heat pump 2, a hot water supply facility 2 </ b> A, a refrigerator-freezer 2 </ b> B, etc.) is underground through the circulating water and the underground heat exchanger (4). Time of heating operation by heat source equipment (heat source heat pump 3, solar heat source heat pump 30, etc.) even if the heat is taken away (during heating operation) or discarded in the ground (during cooling operation) Since heat is supplied to the ground via the circulating water and the ground heat exchanger (4) and the ground heat is taken away during the cooling operation, the temperature of the ground (soil) is It is possible to prevent the temperature from becoming too low (the time when the heating operation is performed) or too high (the time when the cooling operation is performed) than the average temperature. That is, since the soil temperature is positively restored to the natural soil temperature by the night operation of the heat source device 3, the secular change of the soil temperature is hardly seen.
As a result, it is possible to reliably prevent adverse environmental effects caused by abnormally lowering or abnormally increasing underground (soil) temperature compared to the annual average temperature.

Here, in the present invention, the heat source device (3) performs an operation of supplying heat to the ground (when the heating operation is performed), and the heat of the ground (when the cooling operation is performed). Stealing driving is not limited to nights when electricity charges are cheap.
Therefore, if the underground temperature drops too much (during the heating operation of the air conditioner 2) during the daytime (time periods other than the time when the electricity usage fee is cheap), or the underground temperature increases. Even when the air conditioner 2 has passed (during cooling operation of the air conditioner 2), the heat source device (3) is operated to bring the underground temperature close to the annual average temperature (the operation of regenerating the underground or soil thermally is performed). : Regeneration of ground temperature) can prevent the efficiency of the air conditioner (2) from decreasing.

Further, according to the present invention, the air conditioner (2, 2A, 2B, etc.), the heat source mechanism (for example, the heat source heat pump 3), and the heat exchanger (for example, the heat source (for example, circulating water)) and the heat exchanger (for example) 4) is arranged, the same heat medium can be circulated throughout the system, and there is no need to use a plurality of types of heat medium.
For this reason, according to the present invention, as in Patent Document 2, for example, there is no need to switch the operation of performing the operation for the air conditioner during the daytime and performing the operation for recovering the underground temperature at night. . And according to this invention which does not need to perform the switching of the said driving | operation, since it switched to the driving | operation of underground temperature recovery, the time slot | zone which cannot perform an air-conditioning driving | operation does not arise.
Furthermore, according to the present invention, as in Patent Document 1, for example, there is no need to separately provide an auxiliary heat exchanger or the like in order to recover the underground temperature.

In the present invention, the heat source device is configured to regenerate the soil temperature every day (every night) using, for example, cheap electricity at night (heating when performing heating operation, cooling when performing cooling operation). (Claim 2), it can be returned to the natural soil temperature the next morning.
In other words, when the heating operation is performed, the soil temperature is lowered because the heat is collected from the ground, but the soil is heated (regenerated) at night, and the soil temperature is increased by the start of the heating operation the next day. Raised to natural temperature. That is, in the one-day cycle, the soil temperature rises to the natural temperature at the beginning of the cycle. Therefore, the long-term tendency for the soil temperature to decrease can be avoided.
On the other hand, since the heat is dissipated into the ground during cooling operation, the soil temperature rises, but the soil is cooled (regenerated) at night, and the soil temperature is lowered to the natural temperature by the start of heating operation the next day. ing. That is, in a one-day cycle, the soil temperature has dropped to natural temperature at the beginning of the cycle. Therefore, a long-term increase tendency of soil temperature can be avoided.

In the present invention, the driving start temperature of the heat source device (3) is different between nighttime (time zone nt where the electricity usage fee is cheap) and daytime (time zone dt other than the time zone where the electricity usage fee is cheap). In the nighttime (nt) when the electricity rate is cheaper, the frequency or probability that the heat source device (3) operates is higher than during the daytime (dt) when the electricity usage fee is not cheap. (Claim 2).
With such a configuration, the heat source device (3) operates mainly at night (nt) when the electricity rate is low, and is driven only during the day (dt). It is possible to keep the cost to operate underground and regenerate underground to the minimum necessary.

  And since the temperature of the underground or soil does not decrease excessively compared to the annual average temperature, water as a heat medium (circulated water circulating between the air conditioning equipment or heat source equipment and the underground heat exchanger) Even if is used, there is no risk of freezing. Therefore, the use of antifreeze liquid (brine) becomes unnecessary, and there is no fear of soil contamination due to leakage of antifreeze liquid.

In addition, according to the present invention, it is avoided that the temperature of the underground (soil) becomes too low (time for heating operation) or too high (time for cooling operation) than the annual average temperature. Therefore, when the underground heat exchanger is constituted by a tubular coil, when releasing or absorbing heat from the coil, it may be adversely affected by the heat released or absorbed from the adjacent pitch region. Few.
Therefore, it is possible to embed underground heat exchangers (for example, coiled underground heat exchangers) in which heat transfer tubes are arranged at high density, and long rods in deep underground locations as in the prior art. There is no need to bury the underground heat exchanger.
In other words, according to the present invention, it is possible to arrange a coiled underground heat exchanger in a relatively shallow area, and the cost for burying the underground heat exchanger can be kept low. .

In the present invention, for example, in the summer, from 13:00 to 16:00, a contract is concluded with an electric power company that is discounted if power is not consumed during a peak power consumption period during a peak power load period. If it is, the temperature (the temperature of the circulating water: for example, the water temperature TW at the outlet of the underground heat exchanger) for starting the operation of the heat source device (3) (cooling operation for removing underground heat) is increased It is also possible to configure (FIG. 14: TCD4) or not to operate the heat source device (3).
If comprised in that way, it is possible to further reduce the operating cost of the geothermal heat pump system.

The present invention is effective in both ground heat utilization and soil heat storage. In other words, when the circulating water temperature is lower than the natural soil temperature, heat flows from the surrounding soil into the underground heat exchanger (4) in addition to heating by night electricity (soil heat storage).
On the other hand, when the circulating water temperature is higher than the natural soil temperature, heat flows out to the surrounding soil in addition to cooling using the nighttime electric power (cooling to the soil).
Therefore, effective use of geothermal heat is achieved.

  In addition, since the circulating water circulating through the piping system (Lw) exchanges heat with the soil, the temperature (circulating water temperature) is, for example, about natural soil temperature ± 5 ° C (12-22 ° C in the metropolitan area) throughout the year. Can be kept. Therefore, in the air conditioner (water heat source heat pump 2), high efficiency can be obtained when performing either the heating cycle or the cooling cycle.

  In addition, when a plurality of air conditioners (2) are connected to the circulating water piping system (Lw) and the operation of the heating cycle and the cooling cycle is mixed, the exhaust heat of the cooling cycle is collected by the heating cycle. Thus, the exhaust heat of the cooling cycle can be used in the heating cycle (heat recovery is performed on the heating cycle side). If comprised in that way, the burden of a heat source machine (3) and a ground heat exchanger (4) can be reduced by the part of the waste heat of a cooling cycle.

In the present invention, the temperature of the heat medium (for example, circulating water) (for example, the ground water exchanger outlet water temperature TW of the circulating water) is compared with a threshold value to determine whether to heat or heat the heat medium. (Claim 3 and Claim 4), the heat source unit (3) can be operated considering only the underground temperature without considering the operation status of the air conditioner (2, 2A, 2B).
Even in a building in which a space to be cooled and a space to be heated are mixed, the system of the present invention as described above can be operated to cope with the demand for air conditioning.

1 is a block diagram showing a first embodiment of the present invention. It is a front view which shows an example of an underground heat exchanger. It is a top view of the underground heat exchanger of FIG. It is a time-circulation water temperature characteristic figure which shows the outline | summary of control in 1st Embodiment. It is a control flowchart of a 1st embodiment. It is a figure which shows the modification of the control flowchart of 1st Embodiment. It is a time-circulation water temperature characteristic figure which shows the effect of 1st Embodiment at the time of heating operation. It is an elapsed days-circulation water temperature characteristic figure which shows the effect of 1st Embodiment at the time of heating operation. It is a time-circulation water temperature characteristic figure which shows the effect of 1st Embodiment at the time of air_conditionaing | cooling operation. It is an elapsed days-circulation water temperature characteristic figure which shows the effect of 1st Embodiment at the time of air_conditionaing | cooling operation. It is a block diagram which shows the 1st modification of 1st Embodiment. It is a block diagram which shows the 2nd modification of 1st Embodiment. It is a block diagram which shows 2nd Embodiment of this invention. It is a figure which shows the outline | summary of the control in 3rd Embodiment. It is a control flowchart of a 3rd embodiment. It is a figure which shows the modification of the control flowchart of 3rd Embodiment. It is a time-circulation water temperature characteristic figure which shows the problem of the prior art at the time of heating operation. It is the elapsed days-circulating water temperature characteristic figure which shows the problem of the prior art at the time of heating operation. It is a time-circulation water temperature characteristic figure which shows the problem of the prior art at the time of air_conditionaing | cooling operation. It is the elapsed days-circulating water temperature characteristic figure which shows the problem of the prior art at the time of air_conditionaing | cooling operation. It is a block diagram which shows the other prior art. It is a block diagram which shows another prior art. It is a block diagram which shows the other prior art.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
In the drawings, similar members are denoted by the same reference numerals.
First, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows an overall configuration of a geothermal heat pump system (ground heat utilization apparatus) 101 according to the first embodiment.

In FIG. 1, a ground heat utilization heat pump system generally indicated by reference numeral 101 includes four water heat source heat pumps (air conditioning heat pumps) 2, an air heat source heat pump (heat source heat pump) 3, and a geothermal heat exchanger 4. The control unit 5 is a control means.
Four air conditioning heat pumps 2 that are distributed heat pumps are installed in parallel in the air-conditioned space (air conditioning side) 1, and the heat source heat pump 3 is installed outdoors.

The underground heat exchanger 4 is buried in the ground in the vicinity of the air conditioning side 1 and is connected to the four air conditioning heat pumps 2 and the heat source heat pump 3 by a heat medium circulation system (circulation water line) Lw.
Here, in the circulating water line Lw, the four air conditioning heat pumps 2 are arranged in parallel to the heat source heat pump 3.
Near the outlet Jo of the underground heat exchanger 4 in the circulating water line Lw, a temperature sensor 6 for measuring the temperature of water (circulated water) as a heat medium is interposed.

The heat source heat pump 3 is provided to recover (increase or decrease) the underground soil temperature in which the underground heat exchanger 4 is embedded.
The heat source heat pump 3 performs an operation of heating the circulating water circulating in the underground heat exchanger 4 in order to increase the temperature of the soil during a period in which the air conditioning heat pump 2 performs the heating operation (for example, in winter). In the period when the air-conditioning heat pump 2 is performing the cooling operation (for example, summer), it has a function of performing an operation of cooling the circulating water in order to reduce the temperature of the soil.
In other words, when the air conditioning heat pump 2 is performing the heating operation, the heat source heat pump 3 takes heat from the air and heats the circulating water by the amount of the water temperature indicated by the symbol δ in FIG.
Further, when the air conditioning heat pump 2 is performing the cooling operation, the heat source heat pump 3 releases heat into the air and cools the circulating water by the amount of the water temperature indicated by the symbol δ in FIG.

An arrow F attached to the circulating water line Lw indicates the direction of the circulating water that is the heat medium.
On the downstream side of the temperature sensor 6 in the circulating water line Lw, branch points B1, B2, B3, and B4 are provided.
The leftmost air conditioning side heat pump 2 in FIG. 1 is connected to one branch line LD-5 at the branch point B4. Similarly, the air conditioning side heat pump 2 is connected to the branch line LD-2 at the branch point B2, the branch line LD-3 at the branch B3, and the branch line LD-4 at the branch B4, respectively.
The branch lines LD-4, LD-3, and LD-2 to which the air conditioning side heat pump 2 is connected are connected to the downstream junctions G4, G3, and G2, respectively.

A heat source heat pump 3 is interposed in the branch line LD-1 at the branch point B1, and the branch line LD-1 is connected to the junction G1. Here, the branch line LD-1, the heat source heat pump 3 branch point B1, and the junction G1 are disposed outside the air conditioning side 1.
Although not shown in FIG. 1, an expansion tank or the like may be interposed in the circulating water line Lw in order to eliminate the influence of expansion and contraction of the circulating water.

Only the leftmost air-conditioning heat pump 2 in FIG. 1 is indicated by a symbol, but each air-conditioning heat pump 2 includes a compressor 21, a circulating water-refrigerant heat exchanger 22 (condenser or evaporator), and the like. The refrigerant-air heat exchanger 23 (evaporator or condenser) and the refrigerant line Lc are provided.
A direction switching valve (four-way valve) 24 and an expansion valve 25 are interposed in the refrigerant line Lc. The direction switching valve (four-way valve) 24 has a function of enabling switching between the cooling operation and the heating operation by switching the refrigerant circulation direction.
A circulation pump Pw is interposed on the inflow side of the circulating water line Lw connected to the circulating water-refrigerant heat exchanger 22 (below the circulating water-refrigerant heat exchanger 22 in FIG. 1). A check valve Vc is interposed on the outflow side of the circulating water line Lw connected to the circulating water-refrigerant heat exchanger 22 (above the circulating water-refrigerant heat exchanger 22 in FIG. 1). The check valve Vc is interposed in the air-conditioning heat pump 2 that has stopped operating in order to prevent the circulating water from the other heat pumps 2 that are operating from flowing back.

In FIG. 1, small pumps Pw are dispersedly installed in each of the four air conditioning heat pumps 2 to circulate water (circulating water) as a heat medium. You may comprise so that circulating water may be circulated.
In FIG. 1, an air conditioning heat pump 2 is illustrated as a heat utilization device, but instead of the air conditioning heat pump 2, as shown in the second embodiment of FIG. It is also possible to provide it.

The heat source heat pump 3 is different in heat transfer to the refrigerant that exchanges heat with the circulating water-refrigerant heat exchanger 22.
In the air conditioning heat pump 2, during cooling, the heat held by the indoor air is input to the refrigerant by the refrigerant-air heat exchanger 23, and the heat held by the refrigerant is input to the circulating water by the circulating water-refrigerant heat exchanger 22. (Arrow Y2). On the other hand, at the time of heating, the amount of heat held by the circulating water is input to the refrigerant by the circulating water-refrigerant heat exchanger 22, and the heat stored by the refrigerant is input to the indoor air by the refrigerant-air heat exchanger 23 (arrow Y2 and Is the opposite).

On the other hand, in the heat source heat pump 3, when the air conditioning heat pump 2 is performing the cooling operation, the heat held by the circulating water is input to the refrigerant by the circulating water-refrigerant heat exchanger 22 and is held by the refrigerant. Heat is dissipated into the air by the refrigerant-air heat exchanger 23 (arrow Y3). On the other hand, at the time of heating, the heat held by the air is input to the refrigerant by the refrigerant-air heat exchanger 23, and the amount of heat held by the refrigerant is input to the circulating water by the circulating water-refrigerant heat exchanger 22 (What is the arrow Y3? Vice versa).
Other configurations of the heat source heat pump 3 are the same as those of the air conditioning heat pump 2.

Here, boilers (oil and gas), solar water heaters, and various waste heats (waste and biomass incineration facilities, sewage, subways, etc.) can be used as the heat source equipment. In addition, there are refrigerators (electric type and absorption type) for cooling, and cooling towers, rivers, lake water, etc. can be used depending on temperature conditions.
However, in consideration of applicability, as shown in FIG. 1, an air heat source heat pump 3 capable of heating and cooling the circulating water is suitable.

Further, as shown in FIG. 1, four air conditioning heat pumps 2 and a heat source heat pump 3 are connected in parallel, so that each air conditioning heat pump 2 has a cooling operation / heating operation request according to each air conditioning heat pump 2. The air-conditioned space provided with can be cooled or heated.
In FIG. 1, the control unit 5 and the temperature sensor 6 are connected by an input signal line Si, and the control unit 5 and the heat source heat pump 3 are connected by a control signal line So.

The underground heat exchanger 4 in the underground heat utilization heat pump system is shown in detail in FIGS.
2 and 3, the underground heat exchanger 4 has a structure in which a cross-linked polyethylene pipe 8 is wound at a predetermined pitch P around two cylindrical support members 7 erected (embedded) at a predetermined distance. It is.
In the illustrated example, the diameter of the crosslinked polyethylene pipe 8 is 10 to 20 mm, the wound pitch P is several tens of cm, and the total length of the crosslinked polyethylene pipe 8 is about 100 m.
The width B and height H of the coil unit 9 are several m (for example, 2 to 4 m).

  Although illustration is omitted, in the prior art, as an underground heat exchanger, for example, a tube bent in a U shape is inserted into one bore hole (for example, about φ200 to 250 mm) and used. However, in a pipe bent in a U-shape, a sufficient distance between the U-shaped forward path and the return path cannot be obtained, so that they have a thermal influence on each other, and the efficiency of heat exchange is low. Or since it is a single pipe | tube, it has the problem that sufficient heat exchange area will not be obtained unless the burial depth of a pipe | tube is dug down to about 100m.

On the other hand, in the underground heat exchanger 4 shown in FIGS. 2 and 3, the coil interval (winding pitch P) can be increased to about several tens of cm as described above. And since the full length is also sufficiently long, a sufficient heat exchange area can be secured.
If the width B and height H of the coil unit 9 are set to about several meters, the coil unit 9 can be assembled at the factory and transported to the site as it is. Therefore, at the construction site, it is only necessary to embed the number of units 9 according to the equipment capacity underground, and the construction period can be greatly shortened.
Here, in the underground heat exchanger 4 shown in FIGS. 2 and 3, the reason why the coil interval (winding pitch P) can be increased to about several tens of centimeters will be described later.

Control of the geothermal heat pump system shown in FIG. 1 will be described based on the flowchart of FIG. 5 with reference to FIGS.
In FIG. 4, the characteristics of the underground heat exchanger outlet water temperature (vertical axis) and the time (horizontal axis) of the circulating water during both the heating operation and the cooling operation are shown.
Of the two characteristic lines shown in FIG. 4, the upper characteristic lines (characteristic lines passing through points t1, t2, t3, t4, t5, and t6) are characteristic lines when the air conditioning heat pump 2 performs the cooling operation. is there. On the other hand, the lower characteristic lines in FIG. 4 (characteristic lines passing through the points t11, t12, t13, t14, t15, and t16) are characteristic lines when the air conditioning heat pump 2 performs the heating operation.

In the control shown in FIG. 5, the temperature sensor 6 interposed at the outlet of the underground heat exchanger 4 appropriately measures the underground heat exchanger outlet water temperature (TW) of the circulating water.
In step S2, the control unit 5 determines whether the heating operation is performed by the air conditioning heat pump 2, the cooling operation is performed, or the air conditioning heat pump 2 is not operated.
If the air-conditioning heat pump 2 is not operated, it is not necessary to operate the heat source heat pump 3, and the process proceeds to step S10. If the cooling operation is performed by the air conditioning heat pump 2, the process proceeds to step S3. If the heating operation is performed, the process proceeds to step S11.

In step S3 in which the air-conditioning heat pump 2 performs the cooling operation, it is determined whether or not it is a low-cost time zone (so-called “night power” time zone).
If it is not the time zone nt for night power (step S3 is NO), the process proceeds to step S4, and if it is the time zone nt for night power (YES in step S3), the process proceeds to step S7.
In the illustrated embodiment, as clearly shown in FIG. 4, the time zone nt for nighttime power is from 22:00 at night to 8:00 at the next morning.

If step S3 is NO, the time is not the time zone nt of nighttime power but the daytime (time zone dt from 8:00 to 22:00 in FIG. 4). In step S4, it is determined whether the underground heat exchanger outlet water temperature TW of the circulating water exceeds the temperature TCD2 during the daytime. Here, the temperature TCD2 is a set value of a temperature (ground heat exchanger outlet water temperature) at which the heat source heat pump 3 is started and the circulating water cooling operation is started during the daytime cooling operation of the heat source heat pump 3. Threshold).
If the circulating water underground heat exchanger outlet water temperature TW does not exceed the heat source heat pump 3 starting temperature set value TCD2 (NO in step S4), it is not necessary to operate the heat source heat pump 3, and the process proceeds to step S10.
On the other hand, if the circulating water underground heat exchanger outlet water temperature TW exceeds the heat source heat pump 3 starting temperature setting value TCD2 (step S4 is YES) as in the vicinity of time t3 (15:00) in FIG. Proceed to

In step S5, where the circulating water underground heat exchanger outlet water temperature TW exceeds the starting temperature setting value TCD2 during the daytime cooling operation of the heat source heat pump 3, the circulating water is cooled to lower the soil temperature. It judges that it is necessary and performs the circulating water cooling operation by the heat pump 3 for heat sources. If the circulating water cooling operation by the heat source heat pump 3 is performed, the circulating water underground heat exchanger outlet water temperature TW gradually decreases (decreases).
In step S6, it is determined whether or not the circulating water underground heat exchanger outlet water temperature TW that has gradually decreased has reached the stop temperature set value TCD1. Here, the set value TCD1 is a setting of the temperature at which the heat source heat pump 3 is stopped and the cooling operation of the circulating water is stopped during the daytime cooling operation of the heat source heat pump 3 (circulating water underground heat exchanger outlet water temperature). Value (threshold).

  As is apparent from FIG. 4, the set value TCD2 for starting the heat source heat pump 3 is slightly higher than the set value TCD1 for stopping the heat source heat pump 3. A temperature difference (1 ° C. in the example of FIG. 4) is provided between the two. If the set value TCD2 and the set value TCD1 are the same temperature, the heat source heat pump 3 is frequently started and stopped. This is because the heat source heat pump 3 may be damaged. For similar reasons, set temperatures TCN2 and TCN1, set temperatures THN1 and THN2, and set temperatures THD1 and THD2, which will be described later, are also set with a temperature difference (1 ° C. in the example of FIG. 4).

If the circulating water underground heat exchanger outlet water temperature TW has reached the stop temperature set value TCD1 during the cooling operation of the heat source heat pump 3 (YES in step S6: time t5 in FIG. 4), the process proceeds to step S10, and the heat source heat pump 3 is stopped.
When the circulating water underground heat exchanger outlet water temperature TW has not reached the set value TCD1 for stopping the heat source heat pump 3 (NO in step S6), the circulating water cooling operation by the heat source heat pump 3 is continued (step S6). Loop in which S6 is NO: time t3 to time t4 in FIG.
In the example of FIG. 4, the cooling operation of the heat pump 2 for air conditioning is stopped at time t5 (18:00). Therefore, after time t5, the temperature of the circulating cooling water decreases (recovers), and the temperature gradient of the temperature decrease of the circulating water becomes steep.

In step S7, the time zone nt of nighttime electric power, that is, the time zone from time t6 (22:00) to time t2 (8 o'clock the next morning), the circulating water heat exchanger outlet water temperature TW is the heat source heat pump. It is determined whether or not 3 activation set value TCN2 is exceeded. Here, the set value TCN2 is the temperature at which the heat source heat pump 3 is activated at night and the operation for cooling the circulating water is started at the time when the air conditioning heat pump 2 is performing the cooling operation (circulating water underground heat exchanger). This is the set value (threshold value) of the outlet water temperature.
If the circulating water underground heat exchanger outlet water temperature TW does not exceed the heat source heat pump 3 activation set value TCN2 (NO in step S7), the heat source heat pump 3 does not need to be operated, and is stopped in step S10.
If the circulating water underground heat exchanger outlet water temperature TW exceeds the heat source heat pump 3 activation set value TCN2 (YES in step S7), the process proceeds to step S8, and the circulating water cooling operation by the heat source heat pump 3 is started. If the circulating water cooling operation by the heat source heat pump 3 is performed, the soil temperature and the circulating water temperature decrease.

In step S9, it is determined whether or not the circulating water underground heat exchanger outlet water temperature TW has reached the stop temperature set value TCN1 of the heat source heat pump 3. This temperature set value TCN1 is a setting of the temperature at which the cooling operation of the circulating water by the heat source heat pump 3 is stopped at night (the circulating water underground heat exchanger outlet water temperature) when the air conditioning heat pump 2 is performing the cooling operation. Value (threshold).
If the circulating water underground heat exchanger outlet water temperature TW reaches the stop temperature setting value TCN1 of the heat source heat pump 3 (YES in step S9: time t1 in FIG. 4), the process proceeds to step S10 and the heat source heat pump 3 is stopped.
If the circulating water underground heat exchanger outlet water temperature TW has not reached the stop temperature setting value TCN1 of the heat source heat pump 3 (NO in step S9), the cooling operation of the circulating water by the heat source heat pump 3 is continued (step S9). NO loop: time t6 to time t1 in FIG.

  Here, as is apparent from FIG. 4, during the cooling operation of the air conditioning heat pump 2, the start setting value TCN2 of the heat source heat pump 3 at night is lower than the start setting value TCD2 in the daytime. Therefore, at night, the circulating water cooling operation by the heat source heat pump 3 is easier to perform than in the daytime. Thereby, it is possible to concentrate the circulating water cooling operation by the heat source heat pump 3 at night when the power rate is low, and to reduce the operation cost of the entire system 101.

If the heating operation (the air conditioning heat pump 2 is in the heating operation) is selected in step S2, it is determined in step S11 whether or not the time is the nighttime power time zone nt. If it is not the nighttime power time zone (NO in step S11), the process proceeds to step S12. If it is the nighttime power time zone (YES in step S11), the process proceeds to step S15.
Here, a time zone (not a nighttime power time zone) (daytime time zone dt) is a range from time t1d (8 o'clock) to t16 (22:00) in FIG. In such a time zone, in step S12, it is determined whether or not the circulating water underground heat exchanger outlet water temperature TW is lower than the starting temperature set value THD2 of the heat source heat pump 3. Here, the activation temperature set value THD2 is activated during the daytime period dt (time t1d to time t16 in FIG. 4) at the time when the air conditioning heat pump 2 performs the heating operation. It is a set value (threshold value) for the temperature at which the circulating water is heated (circulated water underground heat exchanger outlet water temperature).

  If the circulating water underground heat exchanger outlet water temperature TW is equal to or higher than the starting temperature setting value THD2 of the heat source heat pump 3 (NO in step S12), it is determined that the heating operation of the circulating water by the heat source heat pump 3 is unnecessary. Proceed to S10. On the other hand, if the circulating water underground heat exchanger outlet water temperature TW is lower than the starting temperature setting value THD2 of the heat source heat pump 3 (YES in step S12: region at time t13 in FIG. 4), the process proceeds to step S13.

In step S13, the circulating water is heated by the heat source heat pump 3 to start the operation for raising the soil temperature. If the circulating water heating operation by the heat source heat pump 3 is performed, the temperature of the circulating water gradually rises.
In step S14, it is determined whether or not the rising circulating water underground heat exchanger outlet water temperature TW has reached the stop temperature setting value THD1 of the heat source heat pump 3. Here, the stop temperature set value THD1 is circulated by stopping the heat source heat pump 3 in the daytime period dt (time t1d to time t16 in FIG. 4) during the heating operation of the air conditioning heat pump 2. It is a set value of the temperature (circulating water underground heat exchanger outlet water temperature) at which the operation of heating water is stopped.
If the circulating water underground heat exchanger outlet water temperature TW reaches the stop temperature setting value THD1 of the heat source heat pump 3 (YES in step S14), it is determined that heating of the circulating water by the heat source heat pump 3 is unnecessary, In step S10, the heat source heat pump 3 is stopped. If the circulating water underground heat exchanger outlet water temperature TW has not reached the stop temperature setting value THD1 of the heat source heat pump 3 (NO in step S14), the heating operation of the circulating water by the heat source heat pump 3 is repeated (step S14). NO loop: time period from time t13 to time t14 in FIG.

  When heating operation (air conditioning heat pump 2 heating operation) is selected in step S2, if it is determined in step S11 that it is a time zone nt of nighttime power, that time zone is set to time t16 ( 22:00) to time t1d (8am the next morning). In the time zone nt (time zone of nighttime power: time t16 to time t1d), in step S15, it is determined whether or not the circulating water ground heat exchanger outlet water temperature TW is lower than the starting temperature set value THN2 of the heat source heat pump 3. To do. Here, the activation temperature set value THN2 activates the heat source heat pump 3 during the nighttime power period nt (time t16 to time t1d in FIG. 4) during the heating operation of the air conditioning heat pump 2. It is a set value of the temperature at which the operation for heating the circulating water is started (circulated water underground heat exchanger outlet water temperature).

If the circulating water underground heat exchanger outlet water temperature TW is equal to or higher than the startup temperature set value THN2 (NO in step S15), it is determined that the circulating water heating operation by the heat source heat pump 3 is unnecessary, and the process proceeds to step S10.
On the other hand, if the circulating water underground heat exchanger outlet water temperature TW is lower than THN2 (YES in step S15), the process proceeds to step S16, and the circulating water heating operation by the heat source heat pump 3 is started.

The circulating water temperature or the soil temperature gradually rises by the circulating water heating operation by the heat source heat pump 3.
In step S17, it is determined whether or not the rising circulating water underground heat exchanger outlet water temperature TW has reached the stop temperature set value THN1 of the heat source heat pump 3. Here, the stop temperature set value THN1 stops the heat source heat pump 3 in the nighttime power time zone nt (time t16 to time t1d in FIG. 4) at the time when the air conditioning heat pump 2 performs the heating operation. This is the set value of the temperature at which the operation of heating the circulating water is stopped (the circulating water underground heat exchanger outlet water temperature).
If the circulating water underground heat exchanger outlet water temperature TW has reached the stop temperature set value THN1 (YES in step S17: time t11 in FIG. 4), it is determined that the circulating water heating operation by the heat source heat pump 3 is unnecessary, and the step In S10, the heat source heat pump 3 is stopped.
If the circulating water underground heat exchanger outlet water temperature TW does not reach the stop temperature set value THN1 (NO in step S17), the circulating water heating operation by the heat source heat pump 3 is continued (step S17 is NO loop: FIG. 4). From time t16 to time t11).

Here, as is apparent from FIG. 4, during the heating operation by the air conditioning heat pump 2, the start setting value THN2 of the heat source heat pump 3 at night is higher than the start setting value THD2 in the daytime. Therefore, at night, the circulating water heating operation by the heat source heat pump 3 is more easily performed than in the daytime. As a result, it is possible to concentrate the circulating water heating operation by the heat source heat pump 3 at night when the power rate is low, and to reduce the operation cost of the entire system 101 even during the heating operation by the air conditioning heat pump 2.
In step S10 in FIG. 5, after stopping the heat source heat pump, the process returns to step S1, and step S1 and subsequent steps are repeated.

In FIG. 4, the annual average temperature (or natural soil temperature) of the soil temperature is assumed to be 17 ° C, the nighttime target temperature is set to 17 ° C, the daytime upper limit target temperature is set to 22 ° C, and the daytime lower limit target temperature is set to 12 ° C. Assuming that
These set values can be changed according to the region, the embedment depth of the coil of the underground heat exchanger 4, the design plan, and the like.
In FIG. 4, the nighttime power time zone (nighttime charge time zone) is from 22:00 at night to 8:00 the next morning, but is not limited to this. The specific time of the nighttime power time zone varies depending on the electric power company and contract details.

In FIG. 4, the temperature characteristic line indicated by the symbol Tc indicates the circulating water measured by the temperature sensor 6 provided at the outlet of the underground heat exchanger 4 when the cooling operation by the air conditioning heat pump 2 is assumed in summer, for example. It is a characteristic line of temperature.
The temperature change line Th of FIG. 4 is a characteristic line of the circulating water temperature measured by the temperature sensor 6 provided at the outlet of the underground heat exchanger 4, for example, assuming a heating operation by the air conditioning heat pump 2 in winter. Is shown.
In FIG. 4, the specific numerical value of each temperature is illustrated below.
Night cooling operation start set temperature TCN2 of heat source heat pump 3: 18.5 ° C
Night-time cooling operation stop set temperature TCN1: 17.5 ° C of heat source heat pump 3
Heating source heat pump 3 daytime cooling start setting temperature TCD2: 23 ° C.
Heat source heat pump 3 daytime cooling operation stop set temperature TCD1: 22 ° C
Heat source heat pump 3 night heating operation start set temperature THN2: 15.5 ° C
Heat source heat pump 3 night heating operation stop set temperature THN1: 16.5 ° C
Daytime heating operation start set temperature THD2 of heat source heat pump 3: 11 ° C.
Heat source heat pump 3 daytime heating operation stop set temperature THD1: 12 ° C

Here, the control in the first embodiment is not limited to FIG.
In the control shown in FIG. 5, it is determined in step S2 whether it is a heating operation or a cooling operation.
On the other hand, the control shown in FIG. 6 is a modification of the control in the first embodiment, and omits the judgment corresponding to step S2 in FIG. 5 (the logic circuit for judging whether the heating operation or the cooling operation). Yes.

Hereinafter, control of the geothermal heat pump system 101 shown in FIG. 1 will be described with reference mainly to FIG.
As the temperature of the heat medium, the underground heat exchanger outlet water temperature TW of the circulating water is measured (step S21). Then, it is determined whether the time when the water temperature TW is measured is daytime or nighttime (step S22). If it is daytime (step S22 is “dt”), the process proceeds to step S23. "Nt") Proceed to step S31.

In step S23 (when the time when the water temperature TW is measured is daytime), the water temperature TW is compared with the temperature TCD2 (fourth threshold value in the daytime). If the water temperature TW is equal to or higher than the temperature TCD2 (YES in step S23), the heat source The circulating water (heat medium) is cooled by the heat pump 3 (heat source mechanism) (step S24), and the process proceeds to step S27.
If the water temperature TW is lower than the temperature TCD2 (NO in step S23), the process proceeds to step S25, and the water temperature TW and the temperature TCD1 (third threshold value in the daytime) are compared.
When the water temperature TW is equal to or lower than the temperature TCD1 (step S25 is YES), the cooling water (heat medium) is not cooled by the heat source heat pump 3 (heat source mechanism) (step S26), and the process proceeds to step S27. If the water temperature TW is higher than the temperature TCD1 (NO in step S25), the process proceeds to step S27.

In step S27, the ground water heat exchanger outlet water temperature TW of the circulating water is compared with the temperature THD1 (second threshold value in the daytime), and if the water temperature TW is equal to or higher than the temperature THD1 (YES in step S27), the heat source heat pump 3 is used. The circulating water (heat medium) is not heated by (step S28), and the process returns to step S21. If the water temperature TW is lower than the temperature THD1 (step S27 is NO), the process proceeds to step S29.
In step S29, the water temperature TW is compared with the temperature THD2 (first threshold value in the daytime). When the water temperature TW is equal to or lower than the temperature THD2 (YES in step S29), the circulating heat is heated by the heat source heat pump 3 ( Step S30) and return to Step S21.
If the water temperature TW is higher than the temperature THD2 (NO in step S29), the process returns to step S21.

 Here, the water temperature TW is equal to or lower than the temperature TCD1 (third threshold value in the daytime) (YES in step S25), and the cooling operation of the circulating water (heat medium) by the heat source heat pump 3 (heat source mechanism) is not performed (step S26). If the water temperature TW is equal to or higher than the temperature THD1 (second threshold value in the daytime) (YES in step S27), and the heating operation of the circulating water (heat medium) by the heat source heat pump 3 is not performed (step S28), the daytime Corresponds to the case where the temperature of the heat medium is equal to or higher than the second threshold value and equal to or lower than the third threshold value, and the heat source heat pump 3 is in a state where neither the cooling operation nor the heating operation is performed, that is, the state where the heat source mechanism is stopped. It becomes.

As described above, in step S22, when the time when the water temperature TW is measured is nighttime (step S22 is “nt”), the process proceeds to step S31.
In step S31, the water temperature TW is compared with the temperature TCN2 (fourth threshold value at night). If the water temperature TW is equal to or higher than the temperature TCN2 (YES in step S31), the circulating water is cooled by the heat source heat pump 3 (step S32). ), And proceeds to step S35.
If the water temperature TW is lower than the temperature TCN2 (NO in step S32), the process proceeds to step S33, and the water temperature TW and the temperature TCN1 (third threshold at night) are compared.
When the water temperature TW is equal to or lower than the temperature TCN1 (YES in step S33), the circulating water cooling operation by the heat source heat pump 3 is not performed (step S34), and the process proceeds to step S35. If the water temperature TW is higher than the temperature TCN1 (NO in step S33), the process proceeds to step S35.

In step S35, the water temperature TW is compared with the temperature THN1 (second threshold value at night). If the water temperature TW is equal to or higher than the temperature THN1 (YES in step S35), the circulating water heating operation by the heat source heat pump 3 is not performed. (Step S36), the process returns to Step S21. If the water temperature TW is lower than the temperature THN1 (NO in step S35), the process proceeds to step S37.
In step S37, the water temperature TW is compared with the temperature THN2 (first threshold value at night). If the water temperature TW is equal to or lower than the temperature THN2 (YES in step S37), the circulating heat is heated by the heat source heat pump 3 ( Step S38) and return to Step S21.
When the water temperature TW is higher than the temperature THN2 (step S37 is NO), the process returns to step S21.

 Here, the water temperature TW is equal to or lower than the temperature TCN1 (third threshold at night) (YES in step S33), and the cooling operation of the circulating water (heat medium) by the heat source heat pump 3 (heat source mechanism) is not performed (step S34). When the water temperature TW is equal to or higher than the temperature THN1 (second threshold value at night) (step S35 is YES), the circulating water (heat medium) is not heated by the heat source heat pump 3 (step S36). Corresponds to the case where the temperature of the heat medium is equal to or higher than the second threshold value and equal to or lower than the third threshold value, and the heat source heat pump 3 is in a state where neither the cooling operation nor the heating operation is performed, that is, the state where the heat source mechanism is stopped. It becomes.

The control shown in FIG. 6 will be described with reference to the temperature characteristic line of FIG.
First, the control at the time when the cooling operation by the air conditioning heat pump 2 is performed (the heat source heat pump 3 is the cooling operation: the upper solid line in FIG. 4) will be described.
In FIG. 6, at the time when the cooling operation is performed by the air conditioning heat pump 2 (the heat source heat pump 3 is the cooling operation), the air conditioning heat pump 2 is not operated between the times t1 and t2 in FIG. And the underground heat exchanger exit temperature TW of circulating water is the temperature of temperature TCN1 vicinity, and the heat pump 3 for heat sources is also stopped.

The control routine between t1 and t2 in FIG. 4 is shown in FIG. 6, and after measuring the circulating water underground heat exchanger outlet temperature TW in step S21, in step S22, “nt (night power time zone)” To be judged. Since the temperature TW is a temperature in the vicinity of TCN1 between t1 and t2, TW <TCN2, and Step S31 is “NO”. Since the temperature TW is a temperature in the vicinity of TCN1, “YES” is determined in step S33, and control in which the cooling operation of the circulating water by the heat source heat pump 3 is not performed is selected in step S34.
In step S35, the temperature TW is in the vicinity of TCN1, so "NO" is selected. In step S36, control for not heating the circulating water by the heat source heat pump 3 is selected.
Thereafter, the loop of S21, S22, S31, S33, S34, S35, and S36 is repeated between t1 and t2.

Since the daytime cooling operation by the air conditioning heat pump 2 is started from time t2 in FIG. 4, the circulating water underground heat exchanger outlet water temperature TW rises.
Between the times t2 and t3 in FIG. 4, the circulating water underground heat exchanger outlet temperature TW <TCD2. The control routine between times t2 and t3 in FIG. 6 is “dt (daytime: time zone that is not a nighttime power time zone)” in step S22. Since TW <TCD2, step S23 is “NO”, and step S25 is “ YES ”. As a result, in step S26, it is determined that the heat source heat pump 3 does not perform the operation of cooling the circulating water.

Since TW> THD1 between times t2 and t3 in FIG. 4, step S27 is “YES”, and in step S28, it is determined that the heat source heat pump 3 does not perform the operation of heating the circulating water.
Thereafter, a loop of S21, S22, S23, S25, S26, S27, and S28 is performed between times t2 and t3.
However, at time t2 to t3, the loop of S21, S22, S23, S25, S27, and S28 is performed in the region of TCD2>TW> TCD1.

At time t3 in FIG. 4, the circulating water underground heat exchanger outlet water temperature TW = TCD2. In that case, step S23 becomes "YES" and the control which performs the driving | operation which cools circulating water with the heat pump 3 for heat sources is selected by step S24.
At time t4 in FIG. 4, since TW> TCD1, step S27 is “YES”, and it is determined in step S28 that the operation of heating the circulating water by the heat source heat pump 3 is not performed.

At time t3 to t4 in FIG. 4, the control for cooling the circulating water by the heat source heat pump 3 is selected in step S24 in the preceding control cycle (control described for time t3), and the heat source heat pump is selected. In the cooling operation according to 3, the water temperature TW decreases and becomes TW ≦ TCD2, but TW> TCD1. That is, from time t3 to t4, TCD2 ≧ TW> TCD1.
When TW and TCD2 are compared in step S23 of FIG. 6, since TCD2 ≧ TW> TCD1 at times t3 to t4 as described above, step S23 is “NO”, and step S25 is also “NO”. To be judged. Here, since the process proceeds to step S27 without going through step S26, the cooling operation by the heat source heat pump 3 is continued.

Since TCD2 ≧ TW> TCD1 at times t3 to t4, “YES” is determined in step S27 of FIG. 6, and it is selected in step S28 that the circulating water heating operation by the heat source heat pump 3 is not performed.
As a result, the circulating water cooling operation by the heat source heat pump 3 started in step S24 of FIG. 6 is still continued by the control at the time t3 described above.
In other words, from t3 to t4, a loop of S21, S22, S23, S25, S27, and S28 is performed, and step S26 is not executed. Therefore, in step S24 in the control cycle at time t3, “circulating water cooling operation by heat pump 3 for heat source” Will continue.

At time t4 (18:00) in FIG. 4, the air conditioning heat pump 2 is stopped. As a result, heat is not input to the circulating water in the air conditioning heat pump 2, and the circulating water underground heat exchanger outlet water temperature TW is lowered.
Since TW = TCD1 at time t5, step S25 is determined as “YES” in the control in FIG. 6, and the cooling operation of the circulating water in the heat source heat pump 3 is not performed (step S26). By performing the control in step S26, the circulating water cooling operation of the heat source heat pump 3 is stopped.
Since TCD1> TW between times t5 and t6 in FIG. 4, a loop of S21, S22, S23, S25, S26, S27, and S28 is performed in FIG.

From time t6 (22:00) in FIG. 4, it is a time zone for nighttime power, and step S22 in FIG. 6 is “nt (nighttime)”.
Since TW> TCN2 at time t6, step t31 in FIG. 6 is “YES” between t6 and t1 in FIG. 4, and the circulating water cooling operation by the heat source heat pump 3 is performed in step S32.

Between time t6 and t1, in FIG. 6, it becomes a loop of S21, S22, S31, S32, S35, S36, and the circulating water cooling operation by the heat pump 3 for heat source is continued.
Here, as apparent from FIG. 4, since TCD2> TCN2, the circulating water cooling operation by the heat source heat pump 3 is performed in a concentrated manner in the nighttime power period (between t6 and t1) when the power rate is low. Become.

Next, the control at the time when the heating operation by the air conditioning heat pump 2 is performed (the heat source heat pump 3 is the heating operation: the lower solid line in FIG. 4) will be described.
Between times t11 to t12 in FIG. 4, the air conditioning heat pump 2 is not operated, and the circulating water underground heat exchanger outlet water temperature TW is maintained in the vicinity of the temperature THN1. The control routine between t11 and t12 in FIG. 4 is determined as “nt (nighttime)” in step S22 in FIG. 6, and TW = THN1, so step S31 is “NO”, but step S33 is “YES”. Become. In step S34, it is selected that the circulating water is not cooled by the heat source heat pump 3.

In step S35, since TW = THN1, “YES” is set, and in step S36, it is selected that the circulating water is not heated by the heat pump 3 for heat source.
That is, a loop of S21, S22, S31, S33, S34, S35, and S36 in FIG. 6 is performed between times t11 and t12 in FIG.

Since the heating operation of the air conditioning heat pump 2 is started at time t12 in FIG. 4 (the preheating operation of the air conditioning heat pump 2 is started at time t12), the underground heat exchanger outlet water temperature TW starts to drop.
Between times t1d to t13 in the daytime between times t12 and t13 in FIG. 4, the circulating water underground heat exchanger outlet water temperature TW is higher than THD2 (TW> THD2), and step S23 in FIG. Become.
Since the water temperature TW is equal to or lower than the temperature TCD1 (TW ≦ TCD1) between the times t1d to t13 in FIG. 4, Step S25 is “YES”, and the cooling operation of the circulating water by the heat source heat pump 3 is not performed (Step S26).

If TW ≧ THD1 between times t1d and t13 in FIG. 4, step S27 is “YES”, and in step S28, the heat source heat pump 3 selects not to heat the circulating water.
When THD1>TW> THD2, both step S27 and step S29 are “NO”. In this case, during the time t1d to t13 in FIG. 4, the control that “the circulating water is not heated by the heat source heat pump 3” executed in step S28 when TW ≧ THD1 is continued.

At time t13 in FIG. 4, the circulating water underground heat exchanger outlet water temperature TW = THD2. In that case, in FIG. 6, step S23 becomes "NO", step S25 becomes "YES", and the circulating water by the heat source heat pump 3 is not cooled (step S26). In step S27, since TW <THD1, it is determined “NO”.
In step S29, since TW = THD2, it is determined “YES”, and in step S30, the circulating water is heated by the heat source heat pump 3.
At time t13 to t14 in FIG. 4, the circulating water heating operation by the heat source heat pump 3 is performed, so that the circulating water underground heat exchanger outlet water temperature TW rises.

As a result of the heating operation of the circulating water performed by the heat source heat pump 3 at times t13 to t14 in FIG. 4, the circulating water underground heat exchanger outlet water temperature TW rises and becomes TW> THD2.
In the state of TW> THD2 at times t13 to t14 in FIG. 4, step S23 in FIG. 6 is “NO”, step S25 is “YES”, and step S27 is “NO”, and the process proceeds to step S29. Here, since TW> THD2, step S29 is “NO”, and the process returns to step S21. Thereafter, the loop of steps S21, S22, S23, S25, S27, and S29 is repeated.
In the loop from time t13 to time t14 of FIG. 4 described above, step S28 is not passed, so “control for heating circulating water by heat source heat pump 3 (step S30)” in control at time t13 is continued.

At time t14 (18:00) in FIG. 4, the air conditioning heat pump 2 is stopped. As a result, the heat pump 2 for air conditioning also stops taking heat from the circulating water, the circulating water heat exchanger outlet water temperature TW rises, and the temperature gradient of the circulating water underground heat exchanger outlet water temperature TW suddenly increases. (Temperature TW rises faster) At time t15, TW = THD1.
In FIG. 6, at time t15, step S23 is determined as “NO”, step S25 is determined as “YES”, and step S26 is determined as “YES” in step S27. Then, control is performed so that the circulating water is not heated by the heat source heat pump 3 (step S28). As a result, at time t15, the circulating water heating operation by the heat source heat pump 3 is stopped.
From time t15 to t16, a loop of steps S21, S22, S23, S25, S26, S27, and S28 is performed.

From time t16 (22:00) in FIG. 4, it becomes the time zone nt of nighttime power, and step S22 in FIG. 6 becomes “nt (nighttime)”. At time t16 (22:00) in FIG. 4, TW <THN2.
The control between t16 and t11 in FIG. 4 is determined in FIG. 6 as “nt” in step S22, “NO” in step S31, and “YES” in step S33, and the cooling operation of the circulating water by the heat source heat pump 3 is performed. Control that is not performed is performed (step S34). Then, step S35 is determined as “NO”, and “YES” is determined in step S37. In step S <b> 38, the circulating water is heated by the heat source heat pump 3.

  As is clear from FIG. 4, THN2> THD2, so that the circulating water is more easily heated by the heat source heat pump 3 in the nighttime power period. This makes it possible to concentrate the heating of the circulating water by the heat source heat pump 3 during the nighttime electric power hours when the power rate is low, thereby suppressing the running cost of the entire system.

The effect of 1st Embodiment demonstrated in FIGS. 1-6 is demonstrated with reference to FIGS.
7 and 8 show the effect of the first embodiment when the air conditioning heat pump 2 performs the heating operation, and FIGS. 9 and 10 illustrate the case where the air conditioning heat pump 2 performs the cooling operation. Shows the effect.
FIG. 7 schematically shows a change Twh of soil temperature for 24 hours per day when the air-conditioning heat pump 2 is operated for heating operation in the heat pump system 101 of the first embodiment. In FIG. 7, the natural soil temperature is 17 ° C. In FIG. 7, the heating operation is performed with the air-conditioning heat pump 2 from 8 o'clock to 18 o'clock and the operation for collecting heat from the soil is performed, the natural recovery time zone from the operation from 18 o'clock to 22 o'clock, and 22:00 To 8 am of the following morning is a time zone in which the soil temperature is forcibly recovered by heating the circulating water with the heat source heat pump 3 using nighttime power.

In FIG. 7, since the soil temperature has recovered to the natural soil temperature (17 ° C.) at 7 o'clock the next morning, the heating operation of the circulating water by the heat source heat pump 3 is stopped.
Here, at 22:00, the heating operation of the circulating water by the heat source heat pump 3 is started, so the degree of recovery of the soil temperature, that is, the temperature gradient, changes around 22:00.

  FIG. 9 schematically shows changes in soil temperature during 24 hours a day when the air conditioning heat pump 2 performs a cooling operation in the heat pump system 101 of the first embodiment. In FIG. 9, the natural soil temperature is 17 ° C., the time zone from 8 o'clock to 18 o'clock is the time for performing the cooling operation with the air conditioning heat pump 2 to dissipate heat to the soil, and the heat pump for air conditioning from 18 o'clock to 22 o'clock. During the time zone when the soil temperature naturally drops due to the cooling operation suspension by 2 (natural recovery time zone), from 22:00 to 8:00 the next morning, the heat pump 3 for the heat source is driven using nighttime power to cool the circulating water Thus, it is a time zone (forced recovery time zone) in which the soil temperature is forcibly lowered.

In FIG. 9, since the soil temperature has recovered to the natural soil temperature (17 ° C.) at 7 o'clock in the next morning, the cooling operation by the heat source heat pump 3 is stopped.
At 22:00, since the cooling operation by the heat source heat pump 3 is started, the change of the soil temperature, that is, the temperature gradient is changed around 22:00.

According to 1st Embodiment of the structure mentioned above, when performing heating operation with the heat pump for an air conditioning, as shown in FIG.7 and FIG.8, since soil temperature rises (returns) to natural soil temperature in the morning, Even if the number of days elapses from the start of heating operation by the air conditioning heat pump, the soil temperature does not decrease.
Further, as shown in FIGS. 9 and 10, when the cooling operation is performed by the air conditioning heat pump, the soil temperature is lowered (returned) to the natural soil temperature in the morning, so that the number of days from the start of the cooling operation by the air conditioning heat pump is increased. Even after the passage of time, the soil temperature does not increase.
The change in the soil temperature is actually a complicated curve unlike FIGS. 8 and 10 due to fluctuations in heat exchange and the like.

Moreover, according to 1st Embodiment, it is avoided that the temperature of underground (soil) becomes too low temperature rather than annual average temperature in the period which performs heating operation, and becomes too high in the period which performs cooling operation. It is avoided. Therefore, as shown in FIGS. 2 and 3, even if the underground heat exchanger 4 is formed by winding a tubular coil at a short pitch, the influence of heat released or absorbed from adjacent coils separated by a short pitch is sufficient. Less is.
In the illustrated embodiment, the coiled underground heat exchanger 4 can be embedded in a shallow area in the ground, and a rod-shaped underground heat exchanger is embedded in a deep underground position as in the prior art. There is no need.
In the illustrated embodiment, the case where the natural soil temperature is constant (for example, 17 ° C.) is described. However, when the underground heat exchanger 4 is embedded in a shallow region, the natural soil temperature is changed according to the season. It is desirable to control.
The natural soil temperature can be calculated and predicted, but a temperature sensor (detector) can be embedded in the soil and the signal can be used for control. The temperature sensor is a distance that is not affected by the temperature of the underground heat exchanger, and is a typical depth of the underground heat exchanger (for example, 5 meters away from the end of the underground heat exchanger and 4 meters from the ground surface). It is desirable to embed at a depth of

Moreover, according to 1st Embodiment shown in FIGS. 1-10, it is the heat pump 2 for an air conditioning which is an air-conditioning apparatus, and a heat source mechanism so that heat exchange with the circulating water which is a heat medium common to the whole system 101 may be carried out. Since the heat source heat pump 3 and the underground heat exchanger 4 are disposed, only circulating water can be used as a single heat medium.
Therefore, according to the first embodiment, for example, as in Patent Document 2 shown in FIG. 22, the operation is switched for performing the operation for the air conditioner in the daytime and performing the operation for recovering the underground temperature at night. There is no need. And since the heat source heat pump 3 is operated to recover the underground temperature, there is no time zone during which the air conditioning heat pump 2 cannot be operated.
Furthermore, according to the first embodiment, there is no need to separately provide an auxiliary heat exchanger or the like in order to recover the underground temperature as in Patent Document 1 shown in FIG. 21, for example.

In the first embodiment, the ground water heat exchanger outlet water temperature TW of the circulating water is compared with the threshold value, and it is determined whether the circulating water is cooled or heated by the heat source heat pump 3. Without considering whether the heat pump 2 is performing a cooling operation or a heating operation, the heat source heat pump 3 can be operated and controlled in consideration of only the underground temperature.
And even if it is a building where the space to cool and the space to heat are mixed, it is possible to apply the geothermal heat utilization heat pump system 101 which concerns on 1st Embodiment.

Here, in FIG. 1, the four air conditioning heat pumps 2 are arranged in parallel to the heat source heat pump 3 in the circulating water line Lw. However, it is also possible to arrange four air conditioning heat pumps 2 arranged in parallel with the heat source heat pump 3 in series.
FIG. 11 shows a first modification of the first embodiment, wherein the outlet side of the underground heat exchanger 4 communicates with the inlet side of the heat source heat pump 3, and the outlet side of the heat source heat pump 3 is arranged in parallel. The four air conditioning heat pumps 2 communicated with each other. The outlet sides of the four air conditioning heat pumps 2 arranged in parallel communicate with the inlet side of the underground heat exchanger 4.

FIG. 12 shows a second modification of the first embodiment, and the outlet side of the underground heat exchanger 4 communicates with four air conditioning heat pumps 2 arranged in parallel and arranged in parallel. The outlet side of the four air conditioning heat pumps 2 communicates with the inlet side of the heat source heat pump 3. The outlet side of the heat source heat pump 3 communicates with the inlet side of the underground heat exchanger 4.
Other configurations and operational effects of the first modification example of FIG. 11 and the second modification example of FIG. 12 are the same as those of the first embodiment of FIGS.

Next, a second embodiment of the present invention will be described with reference to FIG.
In FIG. 13, the underground heat utilization heat pump system generally indicated by reference numeral 102 includes a solar heat utilization heat pump 30 instead of the heat source heat pump 3 of FIG. 1 as a heat source side device.

  The solar heat utilization heat pump 30 collects solar heat using an outdoor panel 30P that evaporates the refrigerant, and collects heat from outside air on a cloudy day or at night and uses it for heat pump heating. In addition, the outdoor panel 30P is operated as a refrigerant condenser, and the long-wave radiation and the outdoor heat radiation are used in combination at night to cool the heat pump. Furthermore, the solar cell SG is attached to the surface of the outdoor panel 30P so that solar power generation is possible, and the heat pump and other devices are driven by the electric power (indicated by reference sign ES) obtained by the power generation. It is also possible.

In addition to the air conditioning heat pump 2 on the air conditioning side 1, the ground heat utilization heat pump system 102 includes a hot water supply heat pump 2A, a freezer refrigerator 2B, and a system 2C that directly uses ground heat. Here, examples of the system 2C include a cooling radiation panel and an outside air preheater.
The hot water supply heat pump 2A cools the circulating water in the circulating water line Lw, and the refrigerator-freezer 2B heats the circulating water.
As for the system 2C, the natural soil temperature (for example, 17 ° C.) is within a range of plus or minus several degrees. Therefore, the circulating water can be supplied to, for example, ceiling radiation cooling (cooling radiation panel) and used for cooling. Further, the outside air preheater reduces the outside air load by preheating cold outside air and precooling high temperature outside air.

In FIG. 13, the underground heat exchanger 4 goes to the system 2C that directly uses the underground heat using the solar heat utilization heat pump 30, the air conditioning heat pump 2, the hot water supply heat pump 2 </ b> A, the refrigerator / freezer 2 </ b> B via the header H <b> 1 and the header H <b> 2. Connected in parallel.
More specifically, the circulating water from the underground heat exchanger 4 is supplied to the solar heat utilization heat pump 30 via the header H1 and the line 4-30I. It returns to the underground heat exchanger 4 via the line 4-30O and the header H2.
Circulating water is supplied to the air conditioning heat pump 2 via the header H1 and the line 4-2I, and the circulating water is returned to the underground heat exchanger 4 via the line 4-2O and the header H2.

The circulating water supply side of the hot water supply heat pump 2A communicates with the underground heat exchanger 4 via the header H1, line 4-2AI, and the circulating water discharge side communicates with the underground heat via the line 4-2AO, header H2. It communicates with the exchanger 4.
The circulating water supply side of the refrigerator / freezer 2B communicates with the underground heat exchanger 4 via the header H1, line 4-2BI, and the circulating water discharge side communicates with the underground heat via the line 4-2BO, header H2. Communicate with vessel 4.
In the system 2C, circulating water is supplied via the header H1 and the line 4-2CI, and the discharged circulating water is sent to the underground heat exchanger 4 via the line 4-2CO and the header H2.

  Other configurations and operational effects of the second embodiment shown in FIG. 13 are the same as those of the first embodiment of FIGS.

A third embodiment of the present invention will be described with reference to FIGS.
In the third embodiment, for example, from 13:00 to 16:00 in summer, the starting temperature of the cooling operation (cooling operation of the circulating water) of the heat pump for the heat source is set in other time zones in the time zone in which the power load is maximum. The power consumption by the cooling operation of the heat source heat pump is saved by setting the value higher than that or by not performing the cooling operation of the heat source heat pump.

  The control of the third embodiment can be applied to the geothermal heat pump system 101 according to the first embodiment of FIGS. 1 to 10, or the geothermal heat pump according to the second embodiment of FIG. You may apply to the system 102. FIG. In other words, the control according to the third embodiment (the control shown in FIGS. 14 to 16) can be applied not only to the first embodiment of FIG. 1 but also to the second embodiment of FIG.

FIG. 14 shows the set value and the time of the ground water heat exchanger outlet water temperature of the circulating water during both the heating operation and the cooling operation.
In FIG. 14, during the cooling operation of the air conditioning heat pump 2 from the time 13:00 to the time 16:00, the starting temperature (the circulating water underground heat exchanger outlet water temperature) set value TCD4 for cooling the circulating water by the heat source heat pump 3 is set. (28 ° C in the illustrated example) and a temperature (circulating water underground heat exchanger outlet water temperature) set value TCD3 (27 ° C in the illustrated example) for stopping the operation of cooling the circulating water by the heat source heat pump 3 are set. Has been.

The starting temperature setting value TCD4 (28 ° C.) is a temperature setting for starting the operation of cooling the circulating water by the heat source heat pump 3 during the daytime during the cooling operation of the air conditioning heat pump 2 except for the time zone from 13:00 to 16:00. It is set 5 ° C. higher than the value TCD2 (23 ° C. in the illustrated example).
Further, the stop temperature setting value TCD3 (27 ° C.) stops the operation of cooling the circulating water by the heat source heat pump 3 during the daytime during the cooling operation of the air conditioning heat pump 2 except for the time zone from 13:00 to 16:00. It is set 5 ° C. higher than the temperature set value TCD1 (22 ° C. in the illustrated example).

Next, control according to the third embodiment will be described with reference to FIG.
Here, in FIG. 14, during 13:00 to 16:00 in the summer, the circulating water underground heat exchanger outlet water temperature TW starts the operation for cooling the circulating water by the heat source heat pump 3, the temperature set value TCD2 (other time). If it is higher than the belt by 5 ° C., the heat source heat exchanger 3 is driven.
On the other hand, in the control of FIG. 15, the heat source heat pump 3 is not driven and the cooling operation of the circulating water is not performed from 13:00 to 16:00 in the summer.

In FIG. 15, Step S45, which is a process of determining “Summer 13:00 to 16:00?” Is added between Step S4 (same as FIG. 5) and Step S5 (same as FIG. 5). In the case of 13:00 to 16:00 (step S45 is YES), the heat source heat pump 3 is stopped.
Other parts of the control shown in FIG. 15 are the same as the control shown in FIG.

The control in the third embodiment is not limited to FIG.
The control shown in FIG. 16 shows a modification of the control of FIG. 15, and the control corresponding to step S2 of FIG. 15 (determination of heating operation or cooling operation) is omitted.
In the control of FIG. 16, when step S23 is “YES”, it is determined whether or not it is from 13:00 to 16:00 in summer (step S234), and if it is from 13:00 to 16:00 in summer (step S234). Is YES), the cooling operation of the circulating water by the heat source heat pump 3 is not performed in step S26.
The other parts in the control of FIG. 16 are the same as the control shown in FIG.

  In other words, the control shown in FIG. 14 is performed by changing the underground heat exchanger outlet temperature TW of the circulating water that starts the cooling operation (cooling operation of the circulating water) of the heat source heat pump 2 from 13:00 to 16:00 in summer. Although the temperature TCD4, which is higher than the temperature TCD2, is set to the temperature TCD4, the outlet temperature of the ground water heat exchanger 3 for stopping the cooling operation (circulating water cooling operation) of the heat source heat pump 3 is higher than the temperature TCD1. The temperature TCD3 is set lower than the temperature TCD4.

On the other hand, in the control of FIGS. 15 and 16, control is performed so that the cooling operation of the circulating water (cooling operation of the circulating water) by the heat pump for heat source is not performed from 13:00 to 16:00 in summer.
In any case, if the control is performed as described with reference to FIGS. 14 to 16, the time or frequency with which the heat source heat pump cools the circulating water decreases.
Other configurations and operational effects in the third embodiment of FIGS. 14 to 16 are the same as those of the embodiment of FIGS.

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
For example, although a coiled underground heat exchanger is shown in the illustrated embodiment, an underground heat exchanger having a shape in which a plurality of hairpins are continuous can be used.

DESCRIPTION OF SYMBOLS 1 ... Air-conditioned space / Air-conditioning side 2 ... Air conditioning equipment / Heat pump for air conditioning 3 ... Heat source equipment / Heat pump for heat source 4 ... Heat exchanger / Ground heat exchanger 5 ... Control means / Control unit 6 ... water temperature measuring means / temperature sensor 7 ... cylindrical support member 8 ... crosslinked polyethylene pipe Lw ... piping system / circulating water line

Claims (4)

Air conditioner (2, 2A, 2B), heat medium supplied to the air conditioner, underground heat exchanger (4) for exchanging heat between the heat medium and soil, and cooling or heating the heat medium A heat source mechanism (3), and the heat source mechanism (3) is a geothermal heat utilization device having a function of cooling or heating the heat medium so that the soil temperature is within a predetermined temperature range.
A ground heat utilization apparatus, wherein the air conditioner (2, 2A, 2B), the heat source mechanism (3), and the underground heat exchanger (4) use a single heat medium.  The geothermal heat utilization device according to claim 1, wherein the heat source mechanism (3) has a function of operating based on a temperature (TW) of the heat medium.  The geothermal heat utilization device according to claim 2, wherein the heat source mechanism (3) has a function of operating by comparing a temperature (TW) of the heat medium with a threshold value.  The temperature measuring device (6) for measuring the temperature (TW) of the heat medium is interposed in the vicinity of the outlet (Jo) of the underground heat exchanger (4). The geothermal heat utilization device described.

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