KR101327073B1 - Cascade heat pump system - Google Patents

Abstract

The present invention relates to a cascade heat pump system and, more specifically, to the cascade heat pump which enables a stable hot water supply even though a first refrigerant system is malfunction by utilizing hot water utilized for indoor heating and new regeneration energy as a heat source and improves the heating efficiency of a heat pump. [Reference numerals] (10) First coolant system;(20) Second coolant system;(30) Middle blocking tank;(50) Heating blocking tank;(70) Auxiliary system;(80) Feed head tank

Description

Cascade Heat Pump System {CASCADE HEAT PUMP SYSTEM}

The present invention relates to a cascade heat pump system, and more particularly, by using renewable energy and heating water used for indoor heating as a heat source, stable hot water supply can be continued even when the first refrigerant system is inoperable, and the heat pump The present invention relates to a cascade heat pump system in which the heating efficiency of the apparatus is improved.

In a conventional heat pump system using air as a heat source, when the temperature of a heat source decreases during winter operation, the heat pump system is operated at an excessive compression ratio together with a decrease in evaporation pressure, thereby reducing the operating efficiency of the compressor, which causes a decrease in the overall performance of the heat pump.

In addition, if the evaporation pressure is lowered, the compressor outlet refrigerant temperature may be excessively increased, which may adversely affect the safety of the system.

In addition, when defrosting is required while the refrigerant system is operating in the heating mode, the refrigerant system is operated in the cooling mode for defrosting. Therefore, when the refrigerant system is operating in the defrost mode, indoor heating cannot be performed.

As a related art, there is a Korean Patent Publication No. 10-2011-0066780 (Refrigerant system interlocking water circulation system, published on June 17, 2011).

It is an object of the present invention to provide a cascade heat pump system capable of improving the operating performance of a heat pump and taking in high temperature heating water regardless of an outdoor temperature and an operation mode of a refrigerant system.

In addition, the present invention has an object to improve the driving performance of the heat pump by using renewable energy, such as heat, geothermal and solar heat of the road.

In addition, the cascade heat pump that can be prepared in the heating heat storage tank by forming a layer according to the temperature according to the temperature to prepare for the performance degradation of the heating heat storage tank by the low temperature water of more than 0 30 ℃ or less flowing into the heating heat storage tank during the initial operation of the heat pump. It is an object to provide a system.

In order to solve the above problems,

According to the present invention, a circulation cycle of a first refrigerant is formed, and a first temperature sensor for sensing an external temperature is provided, and a first refrigerant system for exchanging air with the first refrigerant and a circulation cycle of a second refrigerant are provided. And a second refrigerant system for exchanging the second refrigerant and the heat medium, and heat storage means for exchanging heat with the first refrigerant and the second refrigerant, and a second temperature sensor for sensing a temperature of the heat storage means. An intermediate heat storage tank, a heat medium circulation unit in which a circulation cycle of the heat medium is formed so that the heat medium exchanges heat with water supply and heating water, a heating heat storage tank in which the heating water is stored, and the heating water flows between the heating heat storage tank and the intermediate heat storage tank. A heating water circulation unit for forming a circulation cycle, and an auxiliary system for allowing the heating water flowing in the heating water circulation unit to exchange heat with renewable energy And a heat storage means for the intermediate heat storage tank, and determining whether the temperature of the first refrigerant can be raised to a target temperature by the first refrigerant system. The heat storage means absorbs heat from the heating water of the heating water circulation unit when the heat is absorbed from the first refrigerant and the temperature is not increased to the target temperature of the first refrigerant by the first refrigerant system.

When the outside air temperature detected by the first temperature sensor is equal to or less than a first reference temperature, it is determined that the temperature rise is impossible by the first refrigerant system to a target temperature of the first refrigerant, and the first reference temperature is 2 ° C. or less. It is characterized by. In addition, even when the first refrigerant system is in the defrost mode, it is determined that the temperature rise up to a target temperature of the first refrigerant is impossible by the first refrigerant system.

The renewable energy is one selected from solar heat, road heat and geothermal heat.

The intermediate heat storage tank includes an outer case installed to surround the outside of the intermediate heat storage tank, an inlet pipe connected to the heating water circulation unit at an upper portion of the outer case, and supplying heating water, and the heating water at a lower portion of the outer case. It is connected between the circulation unit and the outlet pipe for discharging the heating water supplied to the inlet pipe is provided between the outer case and the intermediate heat storage tank in the interior of the outer case, the through-hole through which the heating water supplied to the inlet pipe can pass is formed And a diffuser installed in a plurality of layers spaced apart from each other.

The heating heat storage tank is provided between a high temperature tank in which heating water of a second reference temperature or more is stored, a low temperature tank in which heating water stored below a second reference temperature is stored in isolation from the high temperature tank, and between the high temperature tank and a low temperature tank of the heating water of the low temperature tank. When the heating is higher than the two reference temperature is provided a bypass valve for flowing the heating water of the low temperature tank to the high temperature tank.

The second reference temperature is within 20 to 40 ℃.

The heat medium circulation unit includes: a first heating heat storage circulation unit and the first heating heat storage circulation unit configured to circulate the heat medium heat-exchanged in the second refrigerant system to be resupplyed to the second refrigerant system after heat exchange with the heating water of the high temperature tank. There is provided a second heating heat storage circulation unit for circulating so that the heat medium branched from and passed through the high temperature tank is supplied to the low temperature tank and resupplyed to the second refrigerant system.

The intermediate heat storage tank acts as a condenser for the first refrigerant system, and acts as an evaporator for the second refrigerant system when the temperature rises to the target temperature of the first refrigerant by the first refrigerant system.

When the auxiliary system is not able to operate normally and heat is generated in the heating storage tank by the heating medium to perform indoor heating with the heating water, the heating is resupplyed to the heating storage tank after heating the room more than the temperature of the heating water discharged from the auxiliary system. When the temperature of the heating water is high, the heating water re-supplied to the heating heat storage tank is supplied to the intermediate heat storage tank through a heating water circulation unit to exchange heat between the heating water and the heat storage means.

The heating water discharged from the intermediate heat storage tank after the heat storage means and the heat exchanger is supplied to the high temperature bath when the temperature of the heating water discharged from the intermediate heat storage tank is high compared with the heating water of the low temperature tank, and the temperature is the same or the intermediate heat storage tank. When the temperature of the heating water discharged from the low is supplied to the low temperature bath.

The cascade heat pump system is connected to the heat medium circulation unit is provided with a hot water tank for storing the water supply heat exchanged with the heat medium.

The first refrigerant is R410a, and the second refrigerant is R134a.

By the above-mentioned problem solving means,

The present invention has the effect of preventing the decrease in efficiency due to the low-temperature heating water flowing into the heating heat storage tank when the initial heating water supply of the heat pump.

The present invention provides the heat source to the heat storage means of the intermediate heat storage tank by using the renewable energy, thereby providing hot water at a high temperature even when the first refrigerant system is broken or operated in the defrost mode.

1 shows schematically a cascade heat pump system according to the invention;
2 is a flow chart illustrating a method of operating the cascade heat pump system of the present invention to provide heating water.
3 is a flow chart illustrating an operation method for providing heating water when the first refrigerant system is operated in an inoperable or defrost mode.
Figure 4 is a flow chart illustrating an operation method for performing the heat storage in the intermediate heat storage tank using the heating water in the same case as in FIG.
FIG. 5 is a flowchart illustrating a method in which the heating water of FIG. 4 is returned to a heating heat storage tank after performing heat storage in the intermediate heat storage tank. FIG.
6 is a view showing an intermediate heat storage tank of the present invention.

Hereinafter, a cascade heat pump system according to the present invention will be described.

1 is a view schematically showing a cascade heat pump system according to the present invention, Figure 2 is a flow chart illustrating an operation method for providing a heating water cascade heat pump system of the present invention, Figure 3 is a first refrigerant system FIG. 4 is a flowchart illustrating an operation method of providing heating water when operated in the inoperable or defrosting mode, and FIG. 4 is a flowchart illustrating an operation method of performing heat storage in an intermediate heat storage tank using heating water in the case of FIG. 3. 5 is a flowchart illustrating a method of returning the heating water to the heating heat storage tank after performing the heat storage in the intermediate heat storage tank, and FIG. 6 is a view showing the middle heat storage tank of the present invention.

Referring to FIG. 1, a cascade heat pump according to an exemplary embodiment of the present invention includes a circulation cycle of a first refrigerant, and is provided with a first temperature sensor (not shown) for sensing an external temperature, wherein the first refrigerant and air are provided. The first refrigerant system 10 to allow heat exchange between the first refrigerant system, the second refrigerant system 20 to form a circulation cycle of the second refrigerant, and the second refrigerant and the heat medium to exchange heat, and the first refrigerant and the second refrigerant The intermediate heat storage tank 30 is provided with heat storage means for heat exchange with the second heat sensor (not shown) for sensing the temperature of the heat storage means, and a circulation cycle of the heat medium is formed so that the heat medium is supplied with water and heating water. A heating medium circulating unit 40 for heat exchange, a heating heat storage tank 50 in which the heating water is stored, and a heating cycle for forming a circulation cycle through which the heating water can flow between the heating heat storage tank 50 and the intermediate heat storage tank 30. Male Circulation Unit (60) And an auxiliary system 70 for allowing the heating water flowing in the heating water circulation unit 60 to exchange heat with the renewable energy.

The first refrigerant system 10 is provided with a compressor, a condenser and an evaporator. When the first refrigerant system 10 is operated in a heating mode, the first refrigerant is compressed by a compressor and the temperature is increased. Through the condensation process in the intermediate heat storage tank (30) it is exchanged with the heat storage means and acts as a heat source, and the circulation cycle of the first refrigerant is introduced again through the evaporator to the compressor.

Like the first refrigerant system 10, the second refrigerant system 20 includes a compressor, a condenser, and an evaporator, and a circulation cycle through which the second refrigerant passes therethrough is formed.

In the present invention, the compressor, the condenser and the evaporator of the first refrigerant system 10 and the second refrigerant system 20 are well known and detailed descriptions thereof will be omitted.

In the present invention, the first refrigerant is used R410a, the second refrigerant is used R134a, may be used as the second refrigerant HFC-1234yf or HFC1234ze.

The intermediate heat storage tank 30 has a circulation cycle of the first refrigerant and a circulation cycle of the second refrigerant to pass through the interior of the intermediate heat storage tank 30, the heat storage means is provided inside the intermediate heat storage tank 30 Heat is exchanged with the refrigerant to be stored in the intermediate heat storage tank (30).

Referring to FIG. 6, the intermediate heat storage tank 30 will be described in more detail. An outer case 31 is installed to surround the outside of the intermediate heat storage tank 30, and the heating water circulates on the outer case 31. An inlet pipe 32 connected to the unit 60 to supply heating water is disposed, and a lower portion of the outer case 31 is connected to the heating water circulation unit 60 to be supplied to the inlet pipe 32. Outflow pipes 33 through which water is discharged are arranged.

In addition, a plurality of through holes 34 provided in a space between the outer case 31 and the intermediate heat storage tank 30 inside the outer case 31 may pass through the heating water supplied to the inlet pipe 32. Is formed, a plurality of diffusers 35 are provided to form a plurality of layers up and down in the space between the outer case 31 and the intermediate heat storage tank (30).

The intermediate heat storage tank 30 includes a circulation cycle of the first refrigerant and a circulation cycle of the second refrigerant, and the intermediate heat storage tank 30 is used as a heat storage tank of the intermediate heat storage tank 30 in the present invention. Water is stored.

That is, the intermediate heat storage tank 30 is thermally stored in water, and heat exchange is performed not only by the first refrigerant and the second refrigerant but also by the heating water.

In addition, the heating water supplied to the inlet is heat-exchanged with the water in the heat storage tank, and as the temperature decreases, the heating water passes through the through hole 34 of the diffuser 35 and moves downward of the intermediate heat storage tank 30 to be discharged to the outlet.

At this time, the heating water flows into the space between the outer case 31 and the intermediate heat storage tank 30 by the diffuser 35 to delay the movement of the heating water storage means of the intermediate heat storage tank 30 The time for heat exchange with is sufficient.

Then, the heating water is stratified by the diffuser 35 in the space between the outer case 31 and the intermediate heat storage tank 30, and the heating water flows into the inlet to provide heat to the heat storage means and smoothly to the outlet. Parallel flow and the counterflow of the said heating water are formed so that it may flow out.

Accordingly, according to the intermediate heat storage tank 30 according to the present invention, the outer case 31 is installed on the outside of the intermediate heat storage tank 30, and a through hole between the intermediate heat storage tank 30 and the outer case 31 ( By mounting the diffuser 35 having the 34 formed therein, the intermediate heat storage tank 30 may serve as another heat exchanger, so that the intermediate heat storage tank 30 may not only perform heat exchange of heat storage means therein. Heat exchange of the heat storage means is enabled by the heating water introduced between the outer case 31.

The intermediate heat storage tank 30 of the present invention as described above is excellent in workability because it can be reused by additionally installing the outer case 31 and the diffuser 35 without discarding the existing intermediate heat storage tank 30. The waste of resources can be prevented.

On the other hand, in Figure 6 in place of the intermediate heat storage tank 30 by installing a conventional heat exchanger by installing a diffuser (35) formed with a through hole 34 in the space between the heat exchanger and the outer case 31, the heat exchanger, the outer case 31 ) And the diffuser 35 may also serve as a conventional intermediate heat storage tank.

The heating heat storage tank 50 is a high temperature tank 51 for storing the heating water of a second reference temperature or more, and the low temperature tank 52 and the high temperature that is isolated from the high temperature tank 51 to store the heating water below the second reference temperature. It is provided between the tank 51 and the low temperature tank 52 so that the heating water of the low temperature tank 52 flows to the high temperature tank 51 when the heating water of the low temperature tank 52 is heated above the second reference temperature. Bypass valve 53 is provided.

The high temperature tank 51 is provided with a supply pipe (not shown) through which the heating water above the second reference temperature can be supplied to a heating pipe (not shown) of the room, and a first return pipe (1) returned from the heating pipe. The low temperature tank 52 is provided with a second return pipe (2) to be returned from the heating pipe.

 The first and second water return pipes 1 and 2 are connected to each other by four-way valves, and allow the heating water to be re-supplied to the high temperature tank 51 or the low temperature tank 52 according to the temperature of the returned water. .

The heat medium circulation unit 40 circulates such that the heat medium heat exchanged in the second refrigerant system 20 is re-supplied to the second refrigerant system 20 after being heat-exchanged with the heating water of the high temperature tank 51. The second refrigerant system 20 is supplied from the heating heat storage circulation unit 41 and the first heating heat storage circulation unit 41 and passed through the high temperature tank 51 to the low temperature tank 52. A second heating heat storage circulation unit 42 is provided to circulate so as to be resupplyed with.

The heat medium circulation unit 40 and the heating water circulation unit 60 are each provided with a circulation pipe line through which the heat medium and the heating water are circulated, and the circulation pipe line includes a pump so that they can be circulated forcibly.

The heat medium circulation unit 40 and the heating water circulation unit 60 in which the heat medium and the heating water are circulated are well known and detailed description thereof will be omitted.

On the other hand, the heat medium used water in the present invention as the heat storage means.

The heating water circulation unit 60 is the heating water discharged from the heating pipe of the room is supplied to the intermediate heat storage tank 30 so that the heat storage means and the heating water can be heat-exchanged, and after the heat exchange the heating water again the heating heat storage tank ( 50) to form a circulation cycle of the heating water to be supplied to.

The auxiliary system 70 is connected in the middle of the circulation cycle of the heating water, and the auxiliary system 70 collects renewable energy such as solar heat, road heat, and geothermal heat to provide heat to the heating water.

The auxiliary system 70 may supply heat energy to the intermediate heat storage tank 30 through a separate heat transfer medium, but in the present invention, the heating water circulation cycle may include the intermediate heat storage tank 30, the auxiliary system 70, and the heating heat storage tank ( It is installed to connect 50, and provided with a plurality of valves when the auxiliary system 70 is operated to block the heating water returned to the heating heat storage tank 50 from entering the heating water circulation unit 60, When the heat storage is required in the intermediate heat storage tank () by using the heating water returned to the heating heat storage tank 50 after the indoor heating is impossible because the auxiliary system 70 cannot be operated in the heating water circulation unit 60. 70 is controlled to be blocked by another plurality of valves so that the heating water does not flow in or the heating water that has already flowed into the auxiliary system 70 does not flow out.

The casing heat pump system according to the present invention is provided with a hot water tank 80 in which the water supply connected to the heat medium circulation unit 40 is stored.

The water supply of the hot water tank 80 is heat-exchanged with the heat medium is supplied to the hot water required for life, such as washing face and washing dishes.

In the casing heat pump system of the present invention, when the heat storage is required in the intermediate heat storage tank 30, the first refrigerant system 10 determines whether the temperature of the first refrigerant can be raised to a target temperature. The heat storage means absorbs heat from the first refrigerant when the temperature can be raised to a target temperature, and the heat storage means is configured to heat the heating water if the temperature is not increased to the target temperature of the first refrigerant by the first refrigerant system 10. It is characterized by absorbing heat from the heating water of the circulation unit.

That is, even though the temperature rise to the target temperature of the first refrigerant is impossible by the first refrigerant system 10, the heat storage is performed in the intermediate heat storage tank 30 by the heating water, thereby improving the overall efficiency of the cascade heat pump system of the present invention. To improve.

Referring to FIG. 2, when the cascade heat pump system according to the present invention is initially driven or the temperature of the heat storage means in the intermediate heat storage tank 30 is lower than the operating temperature (S100), the first refrigerant The system 10 determines whether the temperature can be raised to the target temperature of the first refrigerant (S200).

Here, the operating temperature is 20 to 35 ℃, which is the same as the temperature of the heat storage means maintained in the intermediate heat storage tank 30 by the first refrigerant of the first refrigerant system 10 heat exchange with the heat storage means, The target temperature of the first refrigerant is a temperature within 30 to 50 ℃.

In the present invention, when the temperature can be raised to the target temperature of the first refrigerant by the first refrigerant system 10, the first refrigerant system 10 may be operated in a normal heating mode. When the first refrigerant system 10 is operable in the heating mode, the intermediate heat accumulator acts as a condenser for the first refrigerant system 10 and as an evaporator for the second refrigerant system 20.

Then, the heat storage means is heated by the first refrigerant, and the temperature of the second refrigerant is increased by the heated heat storage means. Accordingly, the temperature of the second refrigerant supplied to the compressor of the second refrigerant system 20 is increased, and the temperature of the second refrigerant discharged from the compressor of the second refrigerant system 20 is further increased. The heat medium flowing in the heat medium circulation unit 40 absorbs heat (S300) from the second refrigerant whose temperature is increased in the heat exchanger installed in the refrigerant system 20.

Therefore, a higher amount of heat is transferred to the heat medium in the second refrigerant flowing in the heat exchanger of the second refrigerant system 20, thereby increasing the temperature rise of the heat medium.

At this time, the condensation temperature of the second refrigerant (the temperature of the second refrigerant discharged from the compressor of the second refrigerant system 20) by the characteristics of each of the refrigerant is the condensation temperature of the first refrigerant (the first refrigerant system ( 10) temperature of the first refrigerant discharged from the compressor.

As described above, when the temperature of the second refrigerant is further increased to exchange heat with the heat medium, the temperature of the water supplied to the hot water tank 80 or the heating water of the heating heat storage tank 50 may be further increased. Thus, by using the cascade heat pump system according to the present invention it is possible to provide higher temperature water supply or heating water.

The high temperature heat medium is supplied to the hot water supply tank 80 or the heating heat storage tank 50, respectively, or at the same time can be controlled by a plurality of valves included in the heat medium circulation unit 40.

When it is impossible to increase the temperature to the target temperature of the first refrigerant by the first refrigerant system 10, the heat storage means of the intermediate heat storage tank 30 is not the first refrigerant but through the heating water circulation unit 60. The heat is supplied from the supplied heating water (S400), and the heat provided by the heat storage means is again supplied to the second refrigerant to further increase the temperature in the heat exchanger of the second refrigerant system 20. The heat exchange between the refrigerant and the heat medium may be performed to supply hot water through the hot water supply tank 80 or to perform heating through the heating heat storage tank 50 (S500).

As an example of the case where it is impossible to increase the temperature to the target temperature of the first refrigerant by the first refrigerant system 10, the first refrigerant system 10 may be operated in the defrost mode.

Referring to the case when the first refrigerant system 10 is operated in the defrost mode with reference to Figure 3, the initial drive of the cascade heat pump system according to the present invention, or the heat storage means in the intermediate heat storage tank (30) When the temperature of the sensor is always lowered than the operating temperature (S100), the temperature of the outside (outside air) measured by the first temperature sensor is compared with the first reference temperature (S110), and the outside measured by the first temperature sensor When the temperature is equal to or less than the first reference temperature, it is determined that the first refrigerant system 10 is the same as the case where it is impossible to increase the temperature up to the target temperature of the first refrigerant.

Further, even when the first refrigerant system 10 is operated in the defrost mode, the first refrigerant system 10 determines that the temperature is not the same as the case where the temperature is not increased to the target temperature of the first refrigerant (S120). .

That is, when heat storage is required in the intermediate heat storage tank 30, the external temperature is measured by the first temperature system and compared with the first reference temperature (S110). When the external temperature is equal to or greater than the first reference temperature, the first refrigerant system ( It is determined whether 10) is operating in the defrost mode (S120).

The first reference temperature is a temperature at which the external temperature is low to lower the thermal efficiency of the first refrigerant. In the present invention, a temperature of 2 ° C. or less of the image is set as the first reference temperature.

When the first refrigerant system 10 is not in the defrost mode, it is again determined by the first refrigerant system 10 whether the temperature can be raised to a target temperature of the first refrigerant (S200). When it is impossible to increase the temperature up to the target temperature of the first refrigerant by the refrigerant system 10, the hot water supply tank 80 undergoes the same process as the step S400 of performing heat storage in the intermediate heat storage tank 30 using the heating water. The hot water is supplied through) or the heating is performed through the heating heat storage tank 50 (S500).

If the first refrigerant system 10 is not in the defrost mode and the temperature can be raised to the target temperature of the first refrigerant by the first refrigerant system 10, the heat exchange between the first refrigerant and the heat storage means (S300) is performed. By providing heat to the heat medium by the hot water supply and heating (S500).

Hereinafter, referring to FIG. 4, an embodiment in which heat storage is performed in the intermediate heat storage tank 30 using the heating water of the present invention will be described. Determine whether it satisfies (S400 ').

If the condition is not satisfied, the process of determining whether the temperature can be raised to the target temperature of the first refrigerant by the first refrigerant system 10 in FIG. 2 is performed (S200), and if the condition is satisfied, the auxiliary system ( It is determined whether 70) is normally operating (S410).

At this time, if it is determined that the normal operation of the auxiliary system 70 is impossible, it is determined whether the heating water of the heating heat storage tank 50 is heat-exchanged by the heat medium (S420).

If the heat exchange between the heat medium and the heating water is not being performed again, a judging step (S400 ′) is satisfied to satisfy the condition of the heat exchange between the heating water and the heat storage means. If the heat exchange between the heat medium and the heating water is performed, the renewable energy is used as a heat source. After comparing the temperature of the heating water (e) withdrawn from the auxiliary system 70 and the temperature of the heating water (c) returned to the heating heat storage tank 50 again after the indoor heating (S430) to return to the heating heat storage tank (50) If the temperature of the heating water (c) is higher, this is supplied to the intermediate heat storage tank 30 through the heating water circulation unit 60 (S450) so that heat exchange is performed between the heating water and the heat storage means (S400). .

If the heating water (e) supplied with heat from the auxiliary system (70) is equal to or less than the temperature of the heating water (c) returned to the heating heat storage tank (50), the heating water from the auxiliary system (70) Water (e) is supplied to the intermediate heat storage tank (30) through the heating water circulation unit 60 (S440) to perform heat exchange between the heating water (e) and the heat storage means (S400), at this time, The heating water c returned to the heating heat storage tank 50 is returned to the heating heat storage tank 50 without being introduced into the heating water circulation unit 60.

On the other hand, even when it is determined that the normal operation of the auxiliary system 70 is possible in step S410 of determining whether the auxiliary system 70 is normally operated, the heating water c returned to the heating heat storage tank 50 is heated. It is to be returned to the heating storage tank 50 without flowing into the water circulation unit 60, and the heating water (e) discharged from the auxiliary system 70 is supplied to the intermediate storage tank 30 (S440).

Referring to Figure 5 will be described in more detail the process of returning the heating water heat exchanged with the heat storage means after the process of Figure 4 to the heating heat storage tank (50) as follows.

In the flowchart of FIG. 4, the auxiliary system 70 determines whether the heating water c returned to the heating heat storage tank 50 satisfies the condition supplied to the intermediate heat storage tank 30 (S450 ′). Heating water (e) to be discharged is supplied to the intermediate heat storage tank (30) (S440) and the heating water (e) and the heat storage means heat exchange (S400), the heating water (c) returned to the heating heat storage tank (50) If the condition that is supplied to the intermediate heat storage tank 30 is the heating water (c) and the heat storage means is the heat exchange (S400).

After the heating water (c) is returned to the heating heat storage tank 50 is heat exchanged with the heat storage means (S400) in the intermediate heat storage tank (30) and the temperature of the heating water (d) withdrawn from the intermediate heat storage tank (30) The temperature of the heating water (a) stored in the low temperature tank 52 of the heating heat storage tank 50 is compared (S451).

When the temperature of the heating water (d) withdrawn from the intermediate heat storage tank 30 is determined to be equal to or lower than the temperature of the heating water (a) in the low temperature tank 52, the heating water (d) withdrawn from the intermediate heat storage tank (30) ) Is returned to the low temperature tank 52 through the heating water circulation unit 60 (S453).

The heating water (a) stored in the low temperature tank (52) is heated by heat exchange (S454) with the second heating heat storage circulation unit (42), and the temperature of the heating water (a) in the low temperature tank (52) is When the two reference temperatures are exceeded, the heating water (a) in the low temperature tank (52) is supplied to the high temperature tank (51) through the bypass valve (53), and the heating water (a) in the low temperature tank (52). ) If the temperature is equal to or less than the second reference temperature, the second heating heat storage circulation unit 42 and the heat exchange (S454) are continuously performed.

The heating water b stored in the high temperature tank 51 is heat-exchanged with the first heating heat storage circulation unit 41 (S457), so that the heating water b of the high temperature tank 51 performs indoor heating. It is determined whether the heat exchange is performed at an appropriate temperature (S458), and when the temperature reaches an appropriate temperature, water is discharged into a heating pipe to perform indoor heating (S500). If the temperature is not suitable for heating the room, the first heating and heat storage circulation unit continues. Heat exchange is performed between the 41 and the heating water of the high temperature tank 51 (S457).

In the present invention, a suitable temperature for heating the heating water of the high temperature tank 51 is set to 80 ℃, which can be changed as necessary.

On the other hand, the heating water (d) discharged from the intermediate heat storage tank 30 and the heating water (d) in the step (S451) of comparing the temperature of the heating water (a) of the low temperature tank (52) (d) ) Is higher than the temperature of the heating water (a) in the low temperature tank 52, the heating water (d) withdrawn from the intermediate heat storage tank 30 is the high temperature tank 51 through the heating water circulation unit 60 Heat exchange with the first heating heat storage circulation unit 41 is performed (S457) until it is returned to S452 and has an appropriate temperature for heating the room.

As described above, in the cascade heat pump system according to the present invention, if heat storage is required in the heat pump intermediate heat storage tank 30, the first refrigerant system 10 determines whether the temperature can be raised to a target temperature of the first refrigerant. If the first refrigerant system 10 is broken, or if the efficiency of the first refrigerant system 10 is deteriorated due to the low external temperature and the first refrigerant system 10 is operated in the defrost mode to operate the first refrigerant If it is difficult to increase the temperature to the target temperature of the refrigerant by the heat storage in the intermediate heat storage tank 30 by using the auxiliary system 70 or the heating water is effective to prevent the efficiency of the second refrigerant system 20 is lowered have.

In addition, a diffuser 35 that is easily installed in the intermediate heat storage tank 30 is provided to improve heat exchange efficiency, and the intermediate heat storage tank 30 and the heating heat storage tank 50 are separately provided so that the heating heat storage tank at the time of initial driving of the heat pump. The low temperature of the heating water introduced into the 50 prevents the performance of the intermediate heat storage tank 30 from being lowered, thereby preventing the overall performance degradation of the heat pump.

When the temperature can be raised to the target temperature of the first refrigerant by the first refrigerant system 10, the heat pump system is caused by two compression processes in the first refrigerant system 10 and the second refrigerant system 20. It is possible to reduce the power consumption of, and to reduce the maintenance cost by using renewable energy, such as solar, road heat and geothermal heat.

It will be understood by those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. It is self-evident.

10: first refrigerant system 20: second refrigerant system
30: intermediate heat storage tank 31: outer case
32: inlet pipe 33: outlet pipe
34: through air 35: diffuser
40: heat medium circulation unit 41: the first heating heat storage circulation unit
42: second heating heat storage circulation unit 50: heating heat storage tank
51: high temperature tank 52: low temperature tank
53: bypass valve 60: heating water circulation unit
70: auxiliary system 80: hot water tank

Claims (14)

A first refrigerant system having a circulation cycle of a first refrigerant, having a first temperature sensor sensing an external temperature, and allowing the first refrigerant to exchange heat with air;
A second refrigerant system in which a circulation cycle of a second refrigerant is formed, and wherein the second refrigerant and the heat medium exchange heat;
An intermediate heat storage tank having heat storage means for exchanging heat with the first refrigerant and the second refrigerant, and a second temperature sensor detecting a temperature of the heat storage means;
A heat medium circulation unit in which a circulation cycle of the heat medium is formed such that the heat medium heat exchanges with water supply and heating water;
A heating heat storage tank in which the heating water is stored;
A heating water circulation unit for forming a circulation cycle in which the heating water flows between the heating heat storage tank and the intermediate heat storage tank; And
And an auxiliary system for allowing the heating water flowing in the heating water circulation unit to exchange heat with renewable energy.
If heat storage is required in the intermediate heat storage tank, the first refrigerant system determines whether the first refrigerant can be heated up to a target temperature, and if the temperature rises to a target temperature of the first refrigerant, the heat storage means generates heat from the first refrigerant. Absorbs,
And the heat storage means absorbs heat from the heating water of the heating water circulation unit when the temperature is not increased to the target temperature of the first refrigerant by the first refrigerant system. The method according to claim 1,
The cascade heat pump system, characterized in that it is determined that the temperature rise to the target temperature of the first refrigerant is impossible by the first refrigerant system when the outside air temperature detected by the first temperature sensor is less than the first reference temperature. The method according to claim 2,
The first reference temperature is,
Cascade heat pump system, characterized in that less than 2 ℃. The method according to claim 1,
When the first refrigerant system is in the defrost mode, the cascade heat pump system, it characterized in that it is determined that the temperature rise to the target temperature of the first refrigerant by the first refrigerant system is impossible. The method according to claim 1,
The renewable energy,
Cascade heat pump system, characterized in that one selected from solar, road heat and geothermal heat. The method according to claim 1,
The intermediate heat storage tank,
An outer case installed to surround the outside of the intermediate heat storage tank;
An inlet pipe connected to the heating water circulation unit at an upper portion of the outer case to supply heating water;
An outlet pipe connected to the heating water circulation unit under the outer case to discharge the heating water supplied to the inlet pipe; And
A diffuser provided between the outer case and the intermediate heat storage tank in the outer case and formed with a plurality of layers spaced apart from each other by forming a through hole through which the heating water supplied to the inlet pipe can pass; Cascade heat pump system. The method according to claim 1,
The heating heat storage tank,
A high temperature tank in which heating water above the second reference temperature is stored;
A low temperature bath in which heating water below a second reference temperature is stored in isolation from the high temperature bath; And
And a bypass valve provided between the high temperature tank and the low temperature tank to allow the heating water of the low temperature tank to flow into the high temperature tank when the heating water of the low temperature tank is heated above the second reference temperature. The method of claim 7,
The second reference temperature is within 20 to 40 ℃ cascade heat pump system, characterized in that. The method of claim 7,
The heat medium circulation unit,
A first heating heat storage circulation unit configured to circulate the heat medium heat-exchanged in the second refrigerant system to be re-supplied to the second refrigerant system after being heat-exchanged with the heating water of the high temperature tank; And
And a second heating heat storage circulation unit which circulates so that the heat medium branched from the first heating heat storage circulation unit and passed through the high temperature tank is supplied to the low temperature tank and re-supplied to the second refrigerant system. Heat pump system. The method of claim 7,
When normal operation of the auxiliary system is impossible and heat is stored in the heating heat storage tank by the heating medium to perform indoor heating with the heating water, it is re-supplied to the heating heat storage tank after the indoor heating than the temperature of the heating water discharged from the auxiliary system. When the temperature of the heating water is high, the cascade heat pump system, characterized in that for supplying the heating water re-supplied to the heating heat storage tank to the intermediate heat storage tank through a heating water circulation unit to heat exchange the heating water and the heat storage means. The method of claim 10,
The heating water discharged from the intermediate heat storage tank after the heat storage means and the heat exchanger is supplied to the high temperature bath when the temperature of the heating water discharged from the intermediate heat storage tank is high compared with the heating water of the low temperature tank, and the temperature is the same or the intermediate heat storage tank. When the temperature of the heating water discharged from the low cascade heat pump system, characterized in that the supply to the low temperature bath. The method according to claim 1,
The intermediate heat storage tank,
The cascade heat pump system, when the temperature rises to the target temperature of the first refrigerant by the first refrigerant system, acts as a condenser for the first refrigerant system, and acts as an evaporator for the second refrigerant system. . The method according to claim 1,
The cascade heat pump system,
And a hot water supply tank connected to the heat medium circulation unit to store the water supply heat exchanged with the heat medium. The method according to claim 1,
The first refrigerant is R410a, the second refrigerant is a cascade heat pump system, characterized in that R134a.

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