KR102160191B1 - Geothermal Cooling and Heating System using Multi stage heat pump - Google Patents

Abstract

The present invention relates to a geothermal cooling and heating system using a multistage heat pump method, which maintains the condition (flow rate, temperature) of the groundwater circulating along the heat pumps at an appropriate level, thereby increasing the cooling and heating efficiency without using a large-capacity facility, while improving the operation rate of the heat pump and preventing damage even if a large amount of the groundwater is supplied in a single geothermal hole. The geothermal cooling and heating system using a multistage heat pump method according to the present invention includes: a geothermal hole constructed under the ground surface; a geothermal heat supply device that supplies groundwater in the geothermal hole including a pumping pump (20), a supply pipe (21), and a return pipe (22); a plurality of heat pumps connected to the geothermal heat supply device and producing cooling and heating heat by using geothermal heat as a heat source to supply the cooling and heating heat to the cooling and heating loads, wherein the geothermal heat supply device includes a storage tank (23) that stores groundwater and then supplies the same to the heat pump, and the heat pump is configured to sequentially pass groundwater, and when the temperature of the groundwater discharged from the heat pump is outside the temperature at which the heat pump can be operated, the groundwater is re-injected into or discharged from the ground.

Description

Geothermal Cooling and Heating System using Multi stage heat pump}

The present invention relates to a geothermal cooling and heating system using a multistage heat pump method, and more particularly, to a geothermal cooling and heating system using a multistage heat pump method capable of efficient operation and construction suitable for Jeju Island conditions (geographic conditions, economic conditions, etc.) .

This part provides background information related to the content of the present application, and is not necessarily prior art.

In areas with ground and topography such as Jeju Island, when groundwater or geothermal wells are developed, there is a difference in the amount of groundwater remaining in almost all groundwater or geothermal wells, but an aquifer with groundwater is found.

In addition, in the case of groundwater in Jeju Island, the flow rate of groundwater flow in the groundwater aquifer is formed almost 10,000 times faster than that of the land part, so when used as a geothermal hole, heat resilience is excellent, and the heat capacity that can be obtained through a single geothermal hole is It is believed that it can secure 3 to 13 times more than wealth.

In addition, the amount of groundwater that can be pumped through a single groundwater drilling or geothermal drilling is difficult for the land part to obtain 100 tons/day, whereas in Jeju Island, it is possible to secure a quantity of 500 tons/day to 1,000 tons/day. It is also.

In addition, Jeju Island is a volcanic island formed by several volcanic activities, and there are several layers of groundwater aquifers formed each time there is volcanic activity, and the groundwater aquifers formed differently by these depths have different amounts of groundwater pumping, water temperature, and water quality. Some of the groundwater aquifers, which are not deep, flow only during the rainy season during the rainy season and dry during dry seasons such as winter, while only air is circulated.Therefore, such underground air is used to heat the agricultural cultivation house.

In addition, since the groundwater temperature in Jeju Island is generally measured around 15℃ throughout the year, the amount of heat that the groundwater holds is expected to be enormous.

On the other hand, Jeju Island is a volcanic island and has a high permeability of groundwater due to the geological characteristics of basalt, so the groundwater level formed underground is formed close to the sea level. In other words, the middle-mountainous areas where development activities are mainly conducted in Jeju Island are located around 200m above sea level.If groundwater is developed in these areas, the groundwater level at these locations is formed at a depth of 200m close to the sea level. There will be. Due to this problem, when the same open underground heat exchanger as the land part is constructed, the land part installs and operates an underwater pumping pump within 100m, whereas the land part has no choice but to install it 200m below the ground level, and the land part has no choice but to install the groundwater level formed during operation from the surface. Compared to the operation within about 30m, Jeju Island has a high permeability and the groundwater aquifer is developed at regular intervals, so the actual operating water level is around 200m close to the natural water level. In this case, the driving power of the pumping pump that is driven to circulate the groundwater is inevitably increased due to the high pumping head, and it is inevitable that it is impossible to secure economical efficiency even in the operation of the geothermal system.

In addition, in the case of Jeju Island, the ordinance stipulates that drilling cores can be recovered through the core drilling method up to the total planned depth when drilling a geothermal hole, and additional drilling depths are limited to 30 m after the natural water level is discovered. . These administrative regulations in Jeju Island generated an astronomical excavation cost in the process of constructing a geothermal well, so there was a problem of inadequate factors when examining economic feasibility from the construction stage of a geothermal well. Moreover, unlike the land part, for the use of groundwater in the open geothermal system used in the geothermal system, the land part is exempting 100% of the groundwater tax for the total water quantity, while Jeju Island has administrative restrictions that only reduce 50%. .

Therefore, in order to operate a geothermal system in Jeju Island, it is necessary to prepare a technical solution that can secure the largest heat capacity through the smallest number of geothermal holes in consideration of the above-described problems and current conditions.

In other words, when the capacity of the heat pump is small, there is a problem that it is impossible to operate in parallel with the heat pump at the same time by pumping a large amount of groundwater for a short period of time, or in case of simultaneous operation, there is a problem that it becomes uneconomical operation due to high power costs and groundwater tax. have.

In addition, even if the capacity of the heat pump is equipped with a large capacity that can suitably match the amount of groundwater pumped, in order to operate such a large-capacity heat pump, a large amount of groundwater must be pumped and circulated, and then re-injected into the geothermal hole. There is a problem that it is insufficient to meet the economic feasibility due to the high burden of underground water tax.

On the other hand, Jeju Island has a case of constructing and operating a geothermal system that allows heat exchange in groundwater with a high flow rate by immersing a sealed heat exchanger under the surface of groundwater additionally excavated 30m from the natural water level after excavating a geothermal hole. In this case, it is possible when the natural water level is approximately 80m from the surface and the operating pressure inside the closed type heat exchanger can be operated within 10kg/cm2.If the natural water level is deeper than that from the surface, the closed type heat exchanger It is difficult to secure the economic feasibility of the facility due to the high manufacturing cost to secure the pressure resistance to meet the pressure resistance due to the high water pressure maintenance of the base material as well as the lowering of operational stability due to excessively high water pressure formed inside and in the connecting pipe. Have.

Therefore, even for a geothermal system developed in a middle-mountainous region, a technical solution that can overcome high water pressure and construct a large-capacity geothermal system is required.

In other words, due to the geological characteristics of Jeju Island, in the case of the middle-mountainous region with high development density, the natural water level was formed at a depth close to the sea level, so it was not possible to install and operate a closed underground heat exchanger due to the high water pressure that was naturally formed. Due to the high head formed by the upward, the power required to pump water to circulate groundwater is large, and the driving efficiency is inevitably lowered due to the increase in power accordingly, and there is a problem that the driving power cost increases due to this.

In order to solve this problem, the present invention is to take full advantage of the characteristics of Jeju Island's geology and groundwater aquifer. In other words, if the amount of groundwater pumped per geothermal well is maximized, the operating power cost of the submersible pumping motor increases significantly, but the pumped groundwater is not only 10 times more abundant than that of the land part, but also re-injected geothermal holes. The groundwater aquifer is configured differently or separated from a distance so that there is no heat exchange or thermal interference between the groundwater supplied to the heat pump and the groundwater returned after heat exchange. This configuration is based on the assumption that the groundwater inlet and outlet temperature difference is 5℃ due to the design of the geothermal heat pump, as the water temperature of the first pumped groundwater is around 15℃. During heating, it is possible to operate two or more heat pumps. Of course, the amount of groundwater pumped out is abundant compared to the land part, so the land part can acquire about 75,600Kcal/h through a single geothermal hole while operating only one geothermal hole, whereas in the case of Jeju Island, 1,000 m3 per day. If the groundwater of is pumped and utilized, 1,000 ㅧ1,000 / 24 ㅧ(40-15) = 1,041,666Kcal/h is calculated when cooling is set.

As a result, it was concluded that it is technically possible to secure a heat capacity of up to 13 times higher in the case of Jeju Island through one geothermal hole, so that economical efficiency can be secured in terms of facility cost, and the operating power cost is also heat exchanged after pumping a large amount of groundwater. As a result, the operating power cost per unit heat capacity can be operated without much difference from that of the land part, thereby securing economic feasibility.

Registered Patent No. 10-1220531 Registered Patent No. 10-1992308

The present invention is to solve the above-described problems, and even if a large amount of groundwater is supplied in a single geothermal hole, the state of the groundwater circulating along the heat pumps (flow rate, temperature) is maintained at an appropriate level. The purpose of this is to provide a geothermal cooling and heating system using a multistage heat pump method that improves the operation rate of the heat pump and prevents damage while increasing the cooling and heating efficiency without using the system.

In order to achieve the above object, the present invention uses a large amount of groundwater by connecting heat pumps in multiple stages to use heat exchanged in series, and a subsequent heat pump based on the temperature of groundwater passing through the multistage heat pumps. The solution principle is to increase the efficiency of the heat pump by controlling the operation and stopping of the system and circulating groundwater with an appropriate flow rate through supplementation of groundwater. In other words, in order to ensure that the quantity of circulating groundwater passing through the heat pump is always maintained at an appropriate flow rate, it is solved that the next stage heat pump operates without flow shortage obstacles by replenishing the quantity of groundwater injected through the reinjection hole. It is done in principle.

A geothermal heating and cooling system using a multi-stage heat pump method according to the present invention comprises: a geothermal ball installed under the ground surface; A geothermal heat supply device for supplying groundwater in the geothermal hole; And a heat pump that produces cooling and heating heat from the geothermal heat supply device as a heat source and supplies it to a cooling/heating load, wherein two or more heat pumps are connected in series so that groundwater passes sequentially, and the two The above heat pump is characterized in that the groundwater is reinjected or discharged into the ground when the temperature of groundwater discharged from the preceding heat pump is outside the temperature at which the heat pump can be operated.

In addition, the geothermal heat supply device includes a storage tank that stores groundwater and then supplies it to the heat pump, wherein two or more heat pumps are connected in series so that the groundwater passes sequentially, and the two or more The heat pump is characterized in that groundwater is re-injected into the ground when the temperature of groundwater discharged from a preceding heat pump is outside the temperature at which the heat pump can be operated.

According to the geothermal cooling and heating system using the multi-stage heat pump method according to the present invention, the utility of groundwater is improved through multi-stage heat exchange (heat pump, etc.), and the operation efficiency is improved accordingly because a large-capacity heat exchange facility is not used. It also has the effect of suppressing the increase in operating costs due to the imposition of the groundwater tax, as it can be minimized.

In addition, in the case of a geothermal well developed in Jeju Island, a storage tank is installed and recirculated in consideration of the characteristics of securing a large amount of pumping water and taking into account the appropriate operating temperature difference of the heat pump, or the groundwater is circulated by configuring the heat pump in multiple stages. By allowing the aquifer to be re-injected at a different depth, the excavation and operation man-hours of geothermal holes can be minimized in comparison with the land part in Jeju Island, thereby enabling economic installation of the geothermal system.

In addition, it is possible to prevent damage to the underground environment that comes from the excavation process of a number of geothermal holes. In addition, it is possible to control the operation and stop of subsequent heat pumps based on the temperature or temperature and flow rate sequentially supplied between multistage heat pumps. It has the effect of improving the operating rate of the pump, preventing damage, and eventually improving the cooling and heating efficiency. Moreover, compared to the onshore part, the cost of drilling a geothermal hole can drastically reduce the number of geothermal holes per unit heat capacity, thus satisfying economic feasibility, and even if a pumping pump installed underwater is installed in a high-depth section, the heat capacity obtained through the geothermal hole By becoming more than 10 times larger than the land area, it is possible to secure economical efficiency in driving power costs and maintenance costs, which has an effect that can greatly contribute to the spread of geothermal systems in Jeju Island.

1 is a system diagram of a geothermal cooling and heating system using a multistage heat pump method according to the present invention.
2 is a view showing a combined geothermal hole applied to a geothermal cooling and heating system using a multistage heat pump method according to the present invention.
3 is a view showing an example in which a storage tank applied to a geothermal cooling and heating system using a multistage heat pump method according to the present invention returns groundwater.
4 is a view showing an example in which the geothermal cooling and heating system using a multistage heat pump method according to the present invention does not operate a storage tank.
5 is a view showing an example in which a heat pump applied to a geothermal cooling and heating system using a multistage heat pump method according to the present invention is used in a shared combination between an air heat system and a geothermal system.
6 is a view showing an example of using a heat pump applied to a geothermal cooling and heating system using a multi-stage heat pump method according to the present invention in series and parallel combinations and using a separate heat exchanger together.
7 is a view showing an example of configuring a system in parallel and in series by a geothermal cooling and heating system using a multistage heat pump method according to the present invention.
8 is a view showing an example in which a geothermal cooling and heating system using a multistage heat pump method according to the present invention uses a front and rear heat pump.
9 is a view showing an example of configuring a buffer storage tank for heat storage at a rear end of a plate heat exchanger applied to a geothermal cooling and heating system using a multistage heat pump method according to the present invention
FIG. 10 is a view showing an example in which a plate-type heat exchanger is configured at a rear end of a storage tank as a modified configuration form of part "A" of FIG. 9;
11 is a view showing an example of operating a storage tank applied to a geothermal cooling and heating system using a multistage heat pump method according to the present invention in multiple stages.
12 is a view showing an example in which groundwater is circulated in series with a storage unit of two stages and a heat exchange means through a geothermal cooling and heating system using a multistage heat pump method according to the present invention.
13 is a view showing an example in which a geothermal cooling and heating system using a multi-stage heat pump method according to the present invention operates a main storage tank and a return storage tank together.
14 is a view showing an example in which the geothermal cooling and heating system using the multi-stage heat pump method according to the present invention heat-exchanges the heat pump and the heat storage tank by a separate heat medium.
15 is a view showing an example in which a geothermal cooling and heating system using a multi-stage heat pump method according to the present invention operates a main storage tank and a return storage tank together, while supplying water with drinking or living water and water supply with hot water.

In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary depending on the intention or custom of users or operators. Therefore, the definition should be made based on the contents throughout this specification.

The geothermal cooling and heating system using the multi-stage heat pump method according to the present invention includes a geothermal hole, a geothermal heat supply device (a pumping device, a storage tank), a heat pump of two or more (three are shown and described as an example), a heat storage tank, and a load side. It is composed of a cooling and heating unit, and the storage tank and heat storage tank of the geothermal heat supply device are selected and used as necessary.

1. Geothermal work

As shown in Fig. 1, the method is divided into a supply side geothermal hole (1) and a return side geothermal hole (2), and as shown in Fig. 2, a method of dividing a single combined use side geothermal hole (3) into a supply unit and a recovery unit have.

The supply-side geothermal hole 1 and the return-side geothermal hole 2 are excavated at different locations to prevent thermal interference between the supplied groundwater and the recovered groundwater, thereby preventing efficiency degradation due to their heat exchange. In other words, even if the supply-side geothermal hole (1) and the return-side geothermal hole (2) are in the same aquifer, the groundwater recovered to the return-side geothermal hole (2) through the distance between each other does not flow directly into the supply-side geothermal hole (1). By doing so, you can expect a relaxed and normal thermal efficiency in the process.

The combined use-side geothermal hole (3) is formed on the ground with different heights of the aquifer (aquifer A, aquifer B), and the pumping position by the pumping pump 20 of the pumping device and the returning position of the return pipe 22 are used. They are located in different aquifers A and B in the side geothermal hole 3 and are blocked from each other by the shielding device 4. Since the shielding device 4 is a location that blocks between the aquifers A and B, the groundwater pumped by the pumping pump 20 flows in from the aquifer A, and the groundwater returned by the return pipe 22 flows out to the aquifer B. Therefore, there is no hot interference between the supply side groundwater and the return side groundwater.

Since these geothermal holes 1, 2, and 3 mean everything including the above-described features, detailed descriptions of other configurations are omitted.

The supply side geothermal hole (1) may be a single hole in the longitudinal direction, or a vertical water collecting hole in the longitudinal direction and a plurality of horizontal or vertical water collecting holes that are radially constructed at the periphery of the vertical water collecting hole to guide groundwater to the vertical water collecting hole. The form of a radial catchment well made of a supply hole is also possible.

In addition, when it is difficult to develop and dispose of the geothermal hole 2 on the return side for reinjecting groundwater, it is natural that the circulated groundwater on the return side may be discharged and consumed.

2. Geothermal heat supply device (pumping device, storage tank)

end. Pumping device.

A pumping device for supplying heat from the ground through groundwater includes a pumping pump 20 for pumping groundwater, a supply pipe 21 for supplying groundwater pumped by the pumping pump 20, and a tertiary heat pump 30-3. It is composed of a water return pipe 22 that returns the groundwater that has passed through the water exchange-side geothermal hole (2) or the water exchange part of the combined use-side geothermal hole (3).

The pumping pump 20 is installed in the supply side of the supply-side geothermal hole 1 or the combined geothermal hole 3 to pump groundwater.

The supply pipe 21 supplies groundwater pumped by the pumping pump 20 to the storage tank 23.

The water return pipe 22 is connected to the primary to tertiary heat pumps 30-1, 30-2, 30-3 to return groundwater to the water return part of the water return-side geothermal hole (2) or the combined geothermal hole (3). do.

I. Storage tank.

Due to the characteristics of Jeju Island, the pumping capacity of the groundwater pumping pump in the geothermal field is 500 tons/day, especially when it encounters a large-scale groundwater aquifer, pumping up to 3,000 tons/day or more is possible. In order to use the entire amount of groundwater with a large flow rate as a heat source for the operation of the heat pump, groundwater is stored in the storage tank 23 and used when necessary, thereby reducing unnecessary pumping and disposal (re-injection) of groundwater.

The storage tank 23 is connected to the supply pipe 21 of the pumping device to first store the pumped groundwater and supply the groundwater under storage to the primary to tertiary heat pumps 30-1, 30-2, 30-3. For example, by installing a booster pump type circulating pump, the amount of groundwater supplied to the heat pump can be adjusted according to the load capacity by controlling the number of circulation pumps or controlling the rotational speed of the circulation pump using an inverter. To be controlled.

After pumping groundwater through one circulation pump, it is supplied to a plurality of heat pumps through a supply header to circulate, or an independent circulation pump for each heat pump may be configured and operated. That is, the primary-side circulation pump is arranged and operated in the primary-side heat pump 30-1, and it is also possible to configure a spare circulation pump to replace the failed circulation pump through the supply header.

The storage tank 23 is for properly supplying groundwater to two or more heat pumps 30-1, 30-2, 30-3, and is based on supplying it to the primary heat pump 30-1. , If some of the circulating groundwater from the secondary and tertiary heat pumps (30-2, 30-3) flows out to the water return-side geothermal hole (2) for reinjection, the secondary and tertiary heat pumps (30-2, 30-2, When replenishment of groundwater is necessary to secure an appropriate groundwater flow rate in 30-3), it is configured to supply groundwater separately to the secondary or tertiary heat pumps (30-2, 30-3) to replenish it. (23) and the primary side heat pump (30-1) are connected to the primary side supply pipe (31-1), while the storage tank (23) is connected to the secondary side heat pump (30-2) and the third side heat pump (30-). The secondary side supplementary pipe 31-2 and the third supplementary pipe 31-3 connected to 3) are provided.

FIG. 1 shows that the reservoir tank 23 only supplies groundwater and the groundwater that has passed through the primary to tertiary heat pumps 30-1, 30-2, and 30-3 is re-injected into the ground. As shown in, it is also possible to be configured to store groundwater that has passed through the primary to tertiary heat pumps 30-1, 30-2, and 30-3 in the storage tank 23 again.

That is, the primary to tertiary return pipes (33-1, 33-2, 33-3) are connected to the storage tank 23 on the discharge side, and the groundwater stored in the storage tank 23 is transferred to the groundwater on the return side. ) Or the inlet side of the water return pipe 22 is connected to the water return part of the combined geothermal hole 3.

At this time, the storage tank 23 installs a temperature sensor TS1 to detect the temperature of the groundwater to be stored, and the controller detects the temperature and the reference temperature of the temperature sensor TS1 (below 5°C in winter, 35°C in summer). Above), the groundwater that is being stored is returned through the return pipe (22) to the return part of the return side geothermal hole (2) or the combined use geothermal hole (3).

In addition, the storage tank 23 may be configured to supply groundwater that is being stored as living water.

The main reason for the operation of the storage tank 23 is that in the case of Jeju Island, when the development is active and geothermal systems are inevitably demanded for cooling and heating of buildings, a large underwater pumping pump (20) ) Is installed, and the pumping pump 20 pumps a large amount of groundwater in a short time, whereas the heat pumps 30-1, 30-2, 30-3 have a type in which the number of operating units is frequently reduced or increased depending on the cooling and heating load. In order to overcome this problem and maintain a stable amount of circulating water, unnecessary groundwater pumping and circulation can be achieved when the circulation pipe is directly connected to the pumping pump 20 because the range of change in groundwater consumption is wide. It is made up. However, although omitted in the drawing, the water level sensor, which is well known, is installed in the storage tank 23, and the pumping pump 20 can be operated and stopped by the water level sensor, so that the storage tank 23 is It is designed to ensure a constant water level and quantity at all times.

3. Heat pump.

By operating the primary to tertiary heat pumps (30-1, 30-2, 30-3) using a single pumping pump (20), it is possible to solve the difficulty of construction for using complex piping and multiple pumping pumps. Heat productivity is also improved, and the primary to tertiary heat pumps (30-1, 30-2, 30-3) are from the storage tank 23 to the primary heat pump (30-1)-the secondary heat pump (30-2)-It is connected in series in the order of the tertiary heat pump (30-3) so that groundwater flows from the primary heat pump (30-1) to the tertiary heat pump (30-3) while heat exchange. , For this purpose, the secondary side connection pipe (32-1) connecting the primary side and the secondary side heat pumps (30-1, 30-2), and the secondary side and the third side heat pump (30-2,30-3) are connected. It includes a tertiary-side connector (32-2).

Since the tertiary heat pump 30-3 is the last heat pump, the tertiary-side water return pipe 33-3 is piped so as to return groundwater to the geothermal hole 2 or 3, of course.

Meanwhile, the groundwater that has passed through the primary or secondary heat pumps 30-1 and 30-2 is returned to the geothermal hole 2 or 3 based on the discharge temperature, and thus, the secondary connection pipe 32-1 ) And the tertiary side connection pipe 32-2 are equipped with a primary side thermometer and a secondary side thermometer for detecting the temperature of groundwater.

In other words, the temperature of the groundwater will change as it passes through the heat pump, and the temperature of the groundwater discharged from each heat pump is detected through the primary and secondary thermometers, and the current detection temperature and reference temperature (heat pump operation When the detection temperature does not meet the reference temperature, groundwater is not supplied to the next heat pump and is returned to the geothermal hole (2 or 3). It is possible by the water return pipe (33-1) and the secondary water return pipe (33-2).

For example, if the water temperature of the first pumped groundwater is 15℃, the difference between the inlet temperature and the outlet temperature is 5℃ when the operating temperature of the heat pump during heating operation is 5℃, and the groundwater temperature passing through the primary heat pump 30-1 is 10. The temperature of the groundwater passing through the secondary heat pump 30-2 is lowered to 5°C. As such, if the temperature of the groundwater flowing into the secondary heat pump 30-2 is 5°C or less, there is a possibility that the inside of the heat exchanger of the secondary and tertiary heat pumps 30-2 and 30-3 may be frozen and damaged during operation. Therefore, groundwater passing through the primary heat pump 30-1 by connecting the secondary connection pipe 32-1 with the primary return pipe 33-1 is not supplied to the secondary heat pump 30-2. It should be injected into the geothermal hole (2 or 3).

In addition, the present invention is configured as follows to detect the quantity of groundwater supplied to the secondary heat pump 30-2 and the tertiary heat pump 30-3 to supplement groundwater when the groundwater is insufficient.

Replenishment of groundwater is made through the secondary side supplementary pipe 31-2 and the third supplementary pipe 31-3 opened and closed by valves, respectively, and the secondary side connection pipe 32-1 and the third side connection pipe 32 The detection flow rate and the reference flow rate of the secondary side flow meter (F1) and the third side flow meter (F2) respectively installed in -2) are compared (compared by the controller).

That is, in order to operate the heat pump, a minimum circulation flow is required. When the circulating flow rate is small, freezing occlusion occurs due to the subcooling phenomenon in the heat exchanger, or when the circulating flow rate is too large, the head of friction loss increases and the driving power of the circulation pump increases, thereby lowering the overall operation efficiency of the geothermal system. Therefore, all heat pumps need to be controlled so that the adjusted circulation flow is passed, and when the circulating groundwater passing through the heat pump increases when operating in the cooling cycle, and the groundwater flows out to the reinjection hole, the insufficient flow rate can be compensated. .

That is, when the detected flow rate of the third flow meter F2 does not satisfy the reference flow rate, the secondary supplement pipe 31-3 is opened to transfer the groundwater of the storage tank 23 through the secondary supplement pipe 31-3. Groundwater with an appropriate flow rate is supplied to the secondary heat pump 30-2 by supplying it to the secondary side connection pipe 32-1. Alternatively, it is possible to compensate for the flow rate by detecting the flow rate of groundwater discharged to the re-injection hole.

When the storage tank 23 and the multi-stage heat pump are operated in this way, it is possible to secure a large heat capacity compared to the land part as follows.

Jeju Island has a geological groundwater aquifer environment in which 500m3 of groundwater per day is generally easily pumped when one geothermal hole is excavated. If the groundwater at 15℃ is pumped in a scale of 500m3 per day, and the groundwater changed to 40℃ is re-injected into another aquifer without thermal interference, the available heat capacity that can be obtained per day is:

Q = WC△t

Where Q is the total heat capacity Kcal/h, W is the circulating water, and LC is the specific heat of water Kcal/kg.K

Δt is the temperature difference between the inlet and outlet of circulating groundwater.

1,000m3ㅧ1,000ㅧ1Kcal/kg.Kㅧ(40℃-15℃) / 24h = 1,041,666Kcal/h

When this heat capacity is converted to freezing tons, it reaches 1,041,666 Kcal/h/3,024 Kcal/h = 344.47 USRT.

This heat capacity can only be expected to have a maximum scale of 25 USRT at a site with a depth of 500 m in a geothermal hole in the land area, while reducing the depth of excavation in a geothermal hole by 1/2, while pumping up a large amount of groundwater and re-injecting without heat interference after heat exchange. The calculation result is obtained that it is possible to secure more than 13.7 times the heat capacity.

In other words, it is known and analyzed that the geothermal system is not economical due to excessive excavation cost of geothermal drilling in Jeju Island, but the characteristics of Jeju Island's geological and groundwater that can pump large amounts of groundwater and re-inject without overflowing groundwater. When the present invention is applied, even if it is a geothermal system for large-capacity cooling and heating of 300 USRT or higher, the load can be satisfied with only one geothermal hole, so that the cost reduction due to the excavation of the geothermal hole increases. It will be said that it has the effect of securing sufficient economic feasibility.

As the heat pump, a common heat pump operated by geothermal and air heat, or a dedicated heat pump operated exclusively by geothermal and air heat is used. In the former case, geothermal heat is configured to exchange heat with the primary heat exchanger of the heat pump, while air heat is configured to heat exchange with the secondary heat exchanger of the heat pump.

4. Heat storage tank.

The heat storage tank 40 recovers heat from the primary to the third heat pumps 30-1, 30-2, 30-3, stores heat, and supplies it to the load-side air conditioner 50, and pumps it through the circulation pump P. Heat medium (antifreeze such as water or ethyl alcohol) or heat medium (gas, etc.) circulated by the compressor installed in the heat pumps (30-1, 30-2, 30-3) through one supply header 51, respectively. After dividing into the supply pipe of the primary to the tertiary heat pump (30-1, 30-2, 30-3), the heat medium returned through each of the return pipes is transferred through one return header 52. After collecting, heat storage.

Of course, it is natural that the form of heat storage can be configured in various forms such as shrinkage heat, ice heat storage, and latent heat storage.

5. Load side air conditioner

The load-side air conditioner (50) is configured to perform heat exchange by circulating the heat medium, and is connected in a structure that allows the heat medium to be circulated directly or to the heat storage tank (40) and then circulates the heat medium, and the heat stored in the heat storage tank (40) is It is supplied and cooled or heated, and is intended for indoors and greenhouses for cultivation.

4 shows an example in which the geothermal cooling and heating system using the multi-stage heat pump method according to the present invention does not use a storage tank, and the supply pipe 21 is connected to the primary supply pipe 31-1 to supply groundwater and 2 The secondary supply pipe 31-2 and the third supply pipe 31-3 are branched from the supply pipe 21. Other configurations are the same as in FIG. 1.

That is, if the storage tank is not used, it is not possible to store groundwater, but it is possible to supply heating and cooling heat by passing the groundwater through the three-stage heat pumps (30-1, 30-2, 30-3), and the temperature of the groundwater. Because circulation control based on and flow rate is possible, failure of the heat pump can be prevented and efficiency can be improved.

Hereinafter, another example that can be implemented by the present invention will be described.

1. Heat pump series and parallel combination connection.

As shown in FIG. 5, for serial and parallel combination of the primary to tertiary heat pumps 30-1, 30-2, and 30-3, it is configured as follows. In particular, in order to meet the large-capacity cooling and heating load, it is necessary to install a number of geothermal excavation water. In this case, in order to utilize the groundwater that is pumped and circulated in a large amount, a plurality of sets of heat pumps are formed in parallel. By arranging a heat pump, the system is configured so that it is possible to construct a large-capacity geothermal system that pumps and circulates a large amount of groundwater. Of course, when such a configuration is made, each stage connected in parallel is first selected according to the size of the load so that serial operation is performed, and these are sequentially connected to the lower stage so that alternate operation can be performed.

When the groundwater pumped from the supply side geothermal hole (1) is connected in parallel between the primary to the tertiary heat pumps (30-1, 30-2, 30-3), each pumped groundwater must be supplied and returned. For this purpose, a storage tank (23) is connected to the supply header 10 and the return side of the primary to tertiary heat pumps 30-1,30-2,30-3 to store groundwater in the storage tank 23 (or It includes a water exchange header 11 to change the heat hole (2) or the combined use geothermal hole (3)}. In addition, a heat exchanger (for example, a plate heat exchanger) 12 is used between the storage tank 23 and the supply header 10 and the return header 11 so that heat exchange is performed without mixing the groundwater and the antifreeze. . That is, the groundwater and the antifreeze in the storage tank 23 are heat-exchanged in the heat exchanger 12, and the supply header 10 and the return header 11 are the primary to the tertiary heat pumps 30-1 and 30-2. ,30-3).

The supply header (10) and the return header (11) are connected through the supply-side parallel pipes (10-1, 10-2, 10-3) and the return-side parallel pipes (11-1, 11-2, 11-3). It is connected to the primary to tertiary heat pumps 30-1, 30-2, 30-3.

The supply-side parallel pipes 10-1, 10-2, and 10-3 and the return-side parallel pipes 11-1, 11-2, and 11-3 are opened and closed through valves, respectively.

The above is a description of the parallel connection, and is configured as follows to enable serial and parallel connections.

Among neighboring heat pumps, the discharge side of the preceding (upstream) heat pump and the inflow side of the following (downstream) heat pump are connected, that is, the discharge side of the primary heat pump 30-1 and the secondary heat pump 30-2 ) A secondary side series connection pipe 34 connecting the inlet side of the secondary side, and a third side series connection pipe 35 connecting the discharge side of the secondary side heat pump 30-2 and the inlet side of the third heat pump 30-3 ). The secondary side and the tertiary side series connection pipes 34 and 35 are opened and closed by valves, respectively.

In the drawing, it is shown that the groundwater is collected in the storage tank 23 and then returned to the ground, but it is also possible to directly return the water to the ground by avoiding the storage tank 23 as in FIG. 1.

end. Serial operation.

Storage tank (23)-Supply header (10)-Primary side supply side parallel pipe (10-1)-Primary side heat pump (30-1)-Secondary side series connection pipe (34)-Secondary side heat pump (30-2) )-Tertiary side series connection pipe (34)-Tertiary heat pump (30-3)-Tertiary side parallel pipe (11-3)-Return header (11)-Groundwater through the path of the reservoir tank (23) It is cycled. All piping is controlled to open and close for the circulation path.

I. Parallel operation.

Storage tank (23)-Supply header (10)-Each supply side parallel pipe (10-1, 10-2, 10-3)-Each heat pump (30-1, 30-2, 30-3)-Each It is operated as a circulation path of the return side parallel pipe (11-1, 11-2, 11-3)-return header (11)-reservoir tank (23).

6 shows the heat of the groundwater through separate primary to tertiary heat exchangers 60-1,60-2,60-3, and the primary to tertiary heat pumps 30-1,30-2,30-3. ). This is for gas circulation.

For example, groundwater supplied through each supply-side parallel pipe (10-1, 10-2, 10-3) is supplied to the primary to tertiary heat exchangers (60-1, 60-2, 60-3). After being returned to the ground, the primary to tertiary heat pumps (30-1,30-2,30-3) have a heat medium in the primary to tertiary heat exchangers (60-1,60-2,60-3) It is configured to circulate and recover heat from groundwater in this process.

7 shows an example of operating a plurality of groups in series and parallel by using the supply header 10 and the return header 11, and through one parallel header 70-1, the primary to the tertiary heat pump ( 30-1,30-2,30-3) are connected in one group, and the fourth to sixth heat pumps (30-4,30-5,30-6) are connected through another parallel header (70-2). Connect in 2 groups.

Each group is configured to enable serial and parallel operation as shown in FIG. 5, while the parallel headers 70-1 and 70-2 are connected in parallel with the supply header 10.

The two groups of heat pumps 30-1,30-2,30-3,30-4,30-5,30-6 are connected to one return header 11.

2. Buffer type water storage tank and two-stage heat pump operation.

8 shows an example in which a buffer-type water storage tank 23 and a heat pump at the front and rear ends, that is, two-stage heat pumps 30F and 30R, are configured and operated.

The supply header 10 is connected to each of the heat pumps of the heat pump 30F at the front end and is connected to the storage tank 23 through a pipe to supply groundwater to the heat pump 30F and the storage tank 23 at the front end. .

The heat pump 30F of the front end is configured to induce heat exchange between the groundwater and the heat medium stored in the heat storage tank 40, and supplies the groundwater to the storage tank 23.

The storage tank 23 is configured to store groundwater supplied from the supply header 10 and the heat pump 30F at the front end and supply it to the heat pump 30R at the rear stage. In addition, the storage tank 23 is configured to be returned to the underground (return-side geothermal hole or a return unit of a combined geothermal hole) when the groundwater in storage does not meet an appropriate temperature.

The rear heat pump 30R is configured to induce heat exchange between the groundwater supplied from the storage tank 23 and the heat medium stored in the heat storage tank 40, and is configured to return the groundwater to the ground.

The heat storage tank 40 is configured such that the internal heat medium circulates each of the front heat pump 30F and the rear heat pump 30R, and collects heat from the front heat pump 30F and the rear heat pump 30R, and then stores heat.

3. Heat exchanger and antifreeze buffer tank operation.

As shown in FIG. 9, an example of using a heat exchanger 12 (plate heat exchanger) and an antifreeze buffer tank 13 for heat exchange between groundwater and antifreeze without using the storage tank 23 is shown. The antifreeze buffer tank 12 and the antifreeze buffer tank 13 are configured to heat exchange between groundwater and antifreeze through the circulation of the antifreeze, and the antifreeze buffer tank 13 allows circulation of the supply header 10 and the return header 11 and the antifreeze. It is configured to supply the antifreeze obtained by recovering the geothermal heat to the heat pumps 30-1, 30-2, and 30-3.

10 shows another example of the heat exchanger 12 and the antifreeze buffer tank 13, and circulates through the groundwater supply pipe 21-the storage tank 23-the heat exchanger 12-the return pipe 22 And, by circulating the antifreeze through the heat exchanger 12, heat exchange with groundwater is performed.

4. Multi-stage storage tank.

As shown in FIG. 11, it shows an example of configuring the storage tank 23 in multiple stages (the drawing shows a three-stage example), and the storage tank 23 is a storage unit of the first to third stages through the bulkhead. It is divided into (23-1, 23-2, 23-3) or consists of three separate tanks.

The 1st to 3rd stage water reservoir (23-1, 23-2, 23-3) and the 1st to 3rd stage heat exchanger are connected in series so that groundwater is stored in the next stage after heat exchange, and geothermal hole (1) → 1 However, the reservoir (23-1) → 1st stage heat exchanger → 2nd stage water storage unit (23-2) → 2nd stage heat exchanger → 3rd stage water storage unit (23-3) → 3rd stage heat exchanger to allow the flow of groundwater A pipe and a pump are configured (the groundwater that has passed through the three-stage heat exchanger is injected into the reinjection hole 2). Therefore, the temperature of the groundwater will change as it goes from the first-stage reservoir (23-1) to the third-stage reservoir (23-3). For example, if the first-stage reservoir (23-1) is 15℃, the second-stage reservoir The water part 23-2 is changed to 20°C, and the third-stage water storage part 23-3 is changed to 25°C.

Of course, in the case of cooling in summer, a large temperature difference can be utilized, so the number of stages in the reservoir can be expanded and operated, and in winter, the water tank can be reduced to two stages to prevent freezing. The number of stages can be arbitrarily adjusted and operated.

In addition, groundwater supplied to the storage tank 23 connects the supply groundwater to the reservoirs 23-1, 23-2, and 23-3 in stages 1 to 3, respectively, and a valve that can be selectively opened and closed is installed. Accordingly, it is possible to alternately operate the water storage units 23-1, 23-2, and 23-3 and each heat exchanger.

The first to third stage heat exchangers are plate heat exchangers or heat exchangers of heat pumps.

12 shows a supply side geothermal hole (1)-a first-stage water reservoir (23-1)-a primary heat exchange means (a primary heat exchanger (12-1) or a primary heat pump (30-1))-a second-stage water reservoir (23-2)-Secondary side heat exchange means {secondary side heat exchanger (12-2) or secondary side heat pump (30-2)}-It shows an example of circulation through the return side geothermal hole (2) as a path . At this time, a circulation pump is configured to circulate groundwater stored in the first-stage water storage unit 23-1 and the second-stage water storage unit 23-2 to the primary heat exchange means and the secondary heat exchange means.

<Reservation water tank and return water storage tank>

As shown in Figure 13, the main storage tank (23S) for storing the groundwater supplied from the supply side geothermal hole (1), a plurality of heat pumps (30-1, 30-2, 30-3, 30-4) (or heat exchange C), the groundwater supplied from the supply side geothermal hole (1) is stored, while the groundwater stored in the main reservoir tank (23S) is supplemented through the supplementary pipe, and the groundwater is supplied to the tertiary heat pump (30-3) or It consists of a water exchange storage tank (23R) that is returned to the hot hole (2).

The return water storage tank 23R stores groundwater supplied from the supply side geothermal hole 1 through a water supply pipe opened and closed by a water supply valve, and the water supply valve is based on the level of groundwater stored in the water return storage tank 23R. It is opened and closed.

A number of heat pumps are divided into series and parallel groups, and the primary and secondary heat pumps (30-1 and 30-2) are divided into the first series and the tertiary and fourth heat pumps (30-3 and 30-). 4) as the second series group, that is, in the primary heat pump 30-1, the discharge side of the groundwater is connected to the inlet side of the secondary heat pump 30-2, and the third heat pump 30-3 ), the discharge side of the groundwater is connected to the inlet side of the fourth heat pump (30-4), and the first series group receives the groundwater stored in the main storage tank (23S) through the main circulation pump (P1). 2Serial group is piped to receive the groundwater stored in the return water storage tank (23R) through the water return circulation pump (P2), and each pipe is equipped with valves (V1, V2, V3, V4) for supplying groundwater in series/parallel. Lose.

V1 opens and closes the water return pipe that is returned to the water return storage tank 23R from the secondary heat pump 30-2, and V2 is the water return pipe between the secondary heat pump 30-2 and the water return side geothermal hole 2 V3 opens and closes the pipe between the supply side of the primary heat pump 30-1 and the supply side of the tertiary heat pump 30-3, and V4 is the main storage tank (23S) and the return storage tank (23R). Open and close the supplementary pipe between ).

Summer season: groundwater supply side geothermal hole (1)-main reservoir tank-main circulation pump-primary side heat pump-secondary side heat pump-return reservoir tank-return circulation pump-primary side heat pump-secondary side heat pump-return side geothermal hole It flows through the path of (2), and the amount of water stored in the water return side storage tank is maintained by the amount of water returned through the secondary side heat pump and the amount supplied from the main storage tank. Valves V1 and V3 are closed, and valve V2 is open.

In other words, while the groundwater passes through the heat pump, the temperature of 15℃ → 20℃, 20℃ → 25℃, 25℃ → 30℃, 30℃ → 35℃ changes, but the heat pump can be operated so that the heat capacity can be reduced with less groundwater heat. There is an effect that can be used greatly.

Winter season: In winter, two-stage heat pumps are operated at 15℃ → 10℃, 10℃ → 5℃ to prevent freeze caused by freezing during circulation of groundwater. To this end, the primary and secondary heat pumps are in series. In addition, the third and fourth heat pumps are a series group and parallel to the series group. At this time, groundwater is supplied to the third heat pump and operated in parallel, separately from being supplied to the primary heat pump through the main circulation pump, or the main storage tank-the main circulation pump-the path of the primary heat pump, the return water storage tank-the return circulation Pump-Operates in parallel through the path of the third heat pump. The valve V1 is closed, and the valves V2 and V3 are open.

14 shows heat storage through the heat medium circulation pipe by connecting the heat pumps 30-1 and 30-2 (or heat exchanger) and the heat storage tank 40 with a heat medium circulation pipe, while heat storage of the heat storage tank 40 An example of piping to be supplied to the load-side heat exchanger 50 is shown.

In this case, the heat pumps 30-1 and 30-2 may be both a heat exchanger-separated heat pump and a heat exchanger built-in heat pump.

FIG. 15 is an embodiment using FIG. 13, and supply headers 10a-1 and 10a-2 and return headers 11a-1 and 11a-2 to each of the main storage tank 23S and the return storage tank 23R. The groundwater that has passed through the heat pumps (or heat exchangers) connected to the main storage tank 20S is returned to the return storage tank 23R, and the recovered groundwater and/or the supply-side geothermal hole ( The groundwater supplied from 1) is supplied to the supply header (10a-2) of the return storage tank (23R), and the groundwater collected in the return header (11a-2) is returned to the geothermal hole (2) on the return side.

Separately, a household water supply means (23S-1) (water supply pipe, water pump) for supplying the groundwater of the main storage tank 23S to drinking water or household water is included, and also, the groundwater of the return storage tank 23R is hot water. It includes a water supply means (23R-1) for water supply.

Since the main storage tank (23S) stores the groundwater of about 15℃ pumped from the supply side geothermal hole (1), it is possible to supply drinking water or household water. That is, it is possible to use both geothermal heat supply. There is no system.

On the other hand, since the return water storage tank 23R stores groundwater whose temperature has risen through the preceding heat pumps, it can be used for hot water supply.

In the drawing, the valve (V1) is to open and close the connection pipe connecting the supply headers (10a-1, 10a-2), and the valve (V2) is to transfer the groundwater of the return water storage tank (23R) to the return side geothermal hole (2). The valve (V3) is a valve that opens and closes the return pipe connecting the return header 11-2 on the return water storage tank 23R side and the geothermal hole 2 on the return side, and the valve ( V4) is to open and close the pipe for returning the groundwater collected in the return header 11-2 to the geothermal hole on the return side.

1: supply side geothermal hole, 2: return side geothermal hole
3: Combined geothermal work,
10,10a-1,10a-2,11a-1,11a-2: supply header,
10-1,10-2,10-3: parallel pipe on the supply side
11: return header, 11-1,11-2,11-3: parallel pipe on the return side
20: pump, 21: supply pipe
22: water return pipe, 23: storage tank
30-1,30-2,30-3: primary to tertiary heat pump
40: heat storage tank, 50: load side air conditioner
60-1,60-2,60-3: primary to tertiary heat exchanger,

Claims (8)

Geothermal engineering installed under the ground surface;
A geothermal heat supply device for supplying groundwater in the geothermal hole;
A heat pump for producing cooling and heating heat from the geothermal heat of the geothermal supply device as a heat source and supplying it to a cooling and heating load;
And a storage tank for receiving and storing groundwater through the geothermal supply device and supplying it to the heat pump,
The two or more heat pumps are connected in series so that groundwater passes sequentially, and in the two or more heat pumps, the temperature of groundwater discharged from the preceding heat pump exceeds the temperature at which the heat pump can be operated. In the case of, it means reinjecting or discharging groundwater into the ground,
The storage tank is divided into a main storage tank that stores groundwater pumped from the geothermal hole and a return storage tank that is supplemented with groundwater pumped from the geothermal hole or groundwater stored in the main storage tank, while the heat pump includes 2 A geothermal cooling and heating system, characterized in that it is connected in series at least one stage and is divided into two groups connected in parallel to the main storage tank and the return storage tank, and is operated by a serial path or a parallel path. delete The method according to claim 1, wherein if the flow rate of groundwater discharged from the two or more heat pumps is detected and the current detection flow rate does not satisfy the reference flow rate, the reservoir tank is supplemented with groundwater in storage. Geothermal heating and cooling system. The supply-side parallel pipe and the return-side parallel pipe respectively connected to the supply side and the return side of the heat pump in order to connect the two or more heat pumps in parallel based on the geothermal heat supply device. and;
A multistage heat pump method characterized in that the heat pump is operated in series or in parallel, including a series connection pipe that connects the discharge side of the preceding heat pump and the inlet side of the following heat pump among the heat pumps and opens and closes by a valve. Geothermal heating and cooling system using The method according to claim 1,
During cooling operation in the summer season, groundwater stored in the main reservoir tank sequentially passes through the first parallel group, and then stored in the return reservoir tank, and the groundwater stored in the return reservoir tank sequentially passes through the second parallel group. While configuring a serial path to be returned, heat pumps of the first parallel group connected to the main reservoir tank are operated during heating operation in winter, or two parallel groups connected to the main reservoir tank and the return reservoir tank are operated in parallel. Geothermal cooling and heating system using a multistage heat pump method, characterized in that. The method according to claim 5, characterized in that it comprises at least one of a household water supply means for supplying the groundwater stored in the main storage tank as drinking water or a household water, and a hot water supply means for supplying the groundwater stored in the exchange water storage tank with hot water. Geothermal cooling and heating system using multi-stage heat pump method. The method according to claim 1, wherein the storage tank is composed of two or more stages so that groundwater does not communicate with each other, and has a storage unit connected to each other through a heat exchanger, and the groundwater is circulated in chain through the storage unit and the heat exchanger Geothermal cooling and heating system using a multistage heat pump method, characterized in that. The method according to claim 1, wherein the geothermal hole is formed of a supply side geothermal hole and a water exchange side geothermal hole formed in different places, or is formed to be connected to different aquifers and is divided into a supply unit and a water return unit through a shielding device that blocks different aquifers. Geothermal cooling and heating system using a multistage heat pump method, characterized in that consisting of a combined geothermal hole.

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