KR20040049212A - Heat pump system using a mixed heat source - Google Patents

Abstract

A geothermal heat exchanger having a heat transfer fluid installed in the ground to absorb the heat of the ground so as to perform cooling and heating by using the ground heat and the sewage heat as heat sources;

A sewage heat exchanger configured to collect a heat source included in domestic sewage or waste water, and comprising a pipe connection selectively sharing the heat transfer fluid of the geothermal heat exchanger;

A heat pump that stores heat transfer fluid regenerated from the geothermal heat exchanger and / or sewage heat exchanger, receives a heat transfer fluid when the pump is operated, performs heat exchange with the heat transfer fluid, and supplies heat exchanged heat energy to a place of use;

Provided is a heat pump system using a complex heat source comprising control means for allowing the two heat exchangers to be used selectively or simultaneously.

Description

Heat pump system using composite heat source {HEAT PUMP SYSTEM USING A MIXED HEAT SOURCE}

The present invention relates to a heat pump system, and more particularly, to a heat pump system using a combined heat source of geothermal and sewage heat that can be cooled by heating the ground heat and sewage heat as a heat source.

Generally, fossil fuels such as coal, petroleum, natural gas, or nuclear fuel are used as energy sources used for home and industrial purposes.

However, fossil fuels pollute the environment due to various pollutants generated in the combustion process, and nuclear fuels generate harmful substances such as water pollution and radioactivity, and these energy sources have limited reserves. Alternative energy development is actively underway.

Among these alternative energies, researches on natural energy such as wind, solar, geothermal and sewage heat have been conducted for a long time. These natural energy have the advantage of obtaining infinite energy with little effect on environmental pollution and climate change. On the other hand, due to the defect of low energy density, increasing the density and converting it into a usable form is a key factor in the development of natural energy technology.

One of such natural energy technologies is known as a bottom pump system that performs cooling and heating using geothermal heat as a heat source. This is a technology for cooling and heating by installing a heat exchanger to recover heat from the ground or discharge heat into the ground. to be.

Geothermal sources are present in groundwater, surface water, and ground. Underground temperature is below 10m, almost 10 ~ 20 ℃ per year. This temperature range is very suitable as a heat source for heat pump for heating and cooling. Geothermal heat pump system is widely used.

In most cases, the heat source of the heat pump is an air heat source method that obtains heat or discharges heat in the air, such as an air conditioner, and a heat source method that discharges heat through a cooling tower. The use of geothermal sources has the advantage that the energy efficiency is very high compared to air heat sources.

Therefore, in the case of cooling in summer, the temperature of the air heat source is difficult to discharge the cooling heat to more than 30 ℃ while the ground heat source is low to 10 ~ 20 ℃ to exhibit a high efficiency by smoothly discharging the heat.

On the contrary, in the case of heating in winter, the air heat source is difficult to supply the heat required for heating at the lowest temperature of -20 ° C, while the underground heat source is 10 to 20 ° C, which can stably supply the heating heat to the heat pump.

When heating the heat pump, the energy efficiency is about 3 ~ 4, which is more than 3 ~ 4 times higher than the boiler's energy efficiency of 0.8 ~ 0.9.

The heat pump system using geothermal heat is known to have the highest energy efficiency among all the heating and cooling technologies using natural energy. Therefore, the heat pump system using geothermal energy is a necessary technology in a situation where energy resources are low and energy costs are high.

On the other hand, it is known to use the waste heat of the sewage discharged from the urban area among the air-conditioning system using the natural energy, such sewage heat is in the range of about 20 ~ 25 ℃ in summer, about 15 ~ 20 ℃ in winter, the amount of In addition, the temperature is high in winter and cool in summer.

Accordingly, in recent years, a heat pump air-conditioning facility using sewage heat is installed in a sewage treatment plant, or a heat pump is operated by waste heat of sewage in a bathroom to produce hot water. The heat source utilization of waste water is very valuable in terms of recycling unused energy and can reduce energy costs.

However, most sewage heat cannot be utilized because the sewage treatment plant is far away from the residential area or the stability of the sewage heat source is insufficient.

Therefore, researches that can utilize sewage heat more actively are being conducted. Especially, apartment complexes emit a large amount of sewage, which can save energy through waste heat recovery.

If geothermal and sewage heat are used as the heat source of the heat pump, they can make a great contribution to energy saving, so a complex method is needed to make up for the shortcomings.

Such a geothermal heating and cooling system has a drawback in contrast to the above advantages, the most representative one is that the initial installation cost for installing the geothermal heat exchanger is significantly higher than other cooling and heating system, and also has a disadvantage of low thermal efficiency.

Therefore, in order to increase thermal efficiency, boilers or cooling towers are often installed separately and used as auxiliary heat sources.

However, such a conventional geothermal heating and cooling device has a problem that additional cost is required to operate the cooling and heating system since the auxiliary heat source must be operated by using fossil fuel energy or electric energy after installing the auxiliary heat source.

The present invention has been made to solve the conventional problems as described above, the object of the present invention is to use the ground heat as the main heat source, the sewage heat as an auxiliary heat source to save the maintenance cost of the cooling and heating system economical It is to provide a heat pump system using a complex heat source of geothermal and sewage heat.

1 is an overall configuration diagram of a heat pump system using a complex heat source according to the present invention.

2 is a view showing the flow of the heat circulation system during heating operation of the heat pump system according to the present invention.

Figure 3 is a view showing the flow of the heat circulation system during the cooling operation of the heat pump system using a complex heat source according to the present invention.

The heat pump system using the combined heat source of geothermal and sewage heat proposed by the present invention, the geothermal heat exchanger having a heat transfer fluid is installed in the ground to absorb the heat of the ground;

A sewage heat exchanger configured to collect a heat source included in domestic sewage or waste water, and comprising a pipe connection selectively sharing the heat transfer fluid of the geothermal heat exchanger;

A heat pump that stores heat transfer fluid regenerated from the geothermal heat exchanger and / or sewage heat exchanger, receives a heat transfer fluid when the pump is operated, performs heat exchange with the heat transfer fluid, and supplies heat exchanged heat energy to a place of use;

Provided is a heat pump system using a complex heat source comprising control means for allowing the two heat exchangers to be used selectively or simultaneously.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail.

1 is a view for explaining a heat pump system using a complex heat source according to the present invention, Figure 2 is a view showing the flow of heat transfer fluid during heating operation of the heat pump system of the present invention, Figure 3 is a view of the present invention A diagram showing the flow of heat transfer fluid during cooling operation of a heat pump system.

The heat pump system using a mixed heat source of geothermal and sewage heat according to the present invention includes a main heat exchanger (10) and a main heat exchanger (10) for performing heat exchange with geothermal heat in a ground where a pipeline through which heat transfer fluid flows is buried underground. When the heat exchange capacity of the heat exchange capacity is lowered, the secondary heat exchanger 20 and the main heat exchanger 10 or the secondary heat exchanger 20 to heat the secondary heat exchanger 20 or the heat exchanger at the same time with the heat exchanger It includes a heat pump 30 to be used for cooling and heating the room.

The main heat exchanger and the secondary heat exchanger (10) (20) of the well-known structure or a similar heat exchanger may be used, the pump (P) between the heat pump 30 for the smooth flow of the heat transfer fluid Is installed.

Substantially, the geothermal heat exchanger may be used as the main heat exchanger 10, and the subsidiary heat exchanger 20 may collect heat sources included in domestic sewage or wastewater, and may cool and heat the heat transfer fluid by cooling or heating the heat transfer fluid. The sewage heat exchanger can be used. Hereinafter, the main heat exchanger will be referred to as a geothermal heat exchanger, and the auxiliary heat exchanger will be referred to as a sewage heat exchanger for better understanding of the present invention.

The geothermal heat exchanger 10 and the sewage heat exchanger 20 may be connected in series or parallel structure by a conduit, and in any manner, the outlet side of these heat exchangers 10 and 20 may be a heat energy storage unit 40 and a conduit ( 12) (22) can be configured to accumulate thermal energy.

The heat transfer fluid of the geothermal heat exchanger 10 and the sewage heat exchanger 20 supplied to the heat energy storage unit 40 is a heat transfer fluid coming from either one of the heat exchangers or both, and the heat pump 30. After the heat exchange is performed in the geothermal heat exchanger (10) and / and the sewage heat exchanger (20) through the pipe (13, 23) to form a system that the heat transfer fluid can circulate.

Subsequently, the heat transfer fluid heat-exchanged in the heat pump 30 is divided in the distributor 50 and returned to the geothermal heat exchanger 10 through the conduit 13 or the sewage heat exchanger 20 through the other conduit 23. Is a system that can return

The distributor 50 has a structure that can be controlled electrically connected to the control unit 60, in this embodiment, the sensor (S1) and the sewage heat exchanger 20 for detecting the heat exchange capacity of the geothermal heat exchanger (10). Comparing the signal transmitted from the sensor (S2) for detecting the heat exchange ability of the one of the conduit 13, 23 is blocked or opened to configure the flow rate of the heat transfer fluid. Such a distributor 50 may be a commonly used electronically controlled variable flow valve or a valve of a similar function.

In addition, the control unit 60 is installed on the heat pump 30 side is connected to the sensor (S3) for detecting the heat capacity. These sensors S1, S2, and S3 may be used as a temperature sensor or a heat sensor.

The geothermal heat exchanger 10 is installed by embedding a polyethylene pipe or a heat exchange pipe made of a material having high thermal conductivity in the ground, and the geothermal heat exchanger 10 may have a structure filled with a heat transfer fluid therein to recover the geothermal heat.

The sewage heat exchanger (20) is immersed in a medium filled with a heat transfer fluid in a place containing domestic sewage or waste water, so that the heat transfer fluid collects a heat source having the living sewage or waste water and is capable of cooling and heating with this heat energy. Since it is commonly used, a detailed description thereof will be omitted.

The heat pump 30 performs a role of an evaporator and a condenser or a condenser and an evaporator in accordance with a heating / cooling mode conversion to achieve heat exchange with the heat transfer fluid transferred from the geothermal heat exchanger 10 and the sewage heat exchanger 20. A compressor (36) and an expansion valve (38) connected between the means (32) and the second heat exchange means (34) and the circulation conduits of these first and second heat exchange means (32) (34), respectively.

The cooling and heating mode can be realized by converting the flow direction of the refrigerant compressed to high temperature and high pressure in the compressor 36. Such mode switching means can be realized by installing generally well-known rotary valves.

In the drawings, reference numerals V1, V2, V3, V4, and V5 refer to valves whose opening and closing are controlled by the controller 60.

Referring to the cooling and heating action of the heat pump system using the composite heat source of the present embodiment as described above is as follows.

First, when the heating mode is selected, the heat transfer fluid absorbing the geothermal and sewage heat in the geothermal heat exchanger 10 and the sewage heat exchanger 20 is stored in the storage unit 40 in the heat storage state, and then the pump P is driven. While starting to move to the heat pump 30 side is moved to the first heat exchange means (32). In this state, the valves V1 and V4 are controlled to the shut-off state and the valves V2 and V5 are controlled to the open state.

In this mode, the compressor 36 is driven and the refrigerant compressed as shown in FIG. 2 passes through the second heat exchange means 34-the swelling valve 38-the first heat exchange means 32-the compressor 36. It will cycle.

As such, the heat transfer fluid supplied from the pump P passes through the first heat exchange means 32 while the refrigerant circulates, and thus heat exchange occurs here.

At this time, the low-temperature low-temperature refrigerant takes away the heat energy of the heat transfer fluid.

In addition, the refrigerant having the heat energy from the heat transfer fluid is compressed to high temperature and high pressure in the compressor 36 and moved to the second heat exchange means 34. The high temperature and high pressure refrigerant transferred to the second heat exchange means 34 is a fan unit ( (Not shown) to release heat to the atmosphere. The released heat travels along a separate duct or pipeline, heating the interior of the building.

The heat transfer fluid deprived of the heat energy from the first heat exchange means 32 is introduced into the geothermal heat exchanger 10 and the solar heat exchanger 20 along the conduits 13 and 23 through the distributor 50 and repeats the above operation. This heating action is the same as that of a conventional geothermal heat exchanger.

If this action is repeated, since the heat capacity of the geothermal heat exchanger 10 and the sewage heat exchanger 20 is lowered at this time, the sensor (S1) (S2) detects each heat capacity and sends a signal to the control unit 60, Another sensor S3 detects the heat exchange capacity of the heat pump 30 and sends it to the controller 60.

The sensor S3 may determine a heat exchange capability by detecting a difference between an inlet side temperature and an outlet side temperature of the heat transfer fluid flowing into the first heat exchange unit 32.

When such a signal is input, the controller 60 controls the distributor 50 to uniformly return the amount of heat transfer fluid through the conduits 13 and 23, or which one of the conduits is to be blocked, or which one Decide whether to reduce the amount of heat transfer fluid flowing into the pipeline.

The control of this distributor 50 is necessary for proper compensation as the heat capacity of the geothermal heat exchanger 10 and sewage heat exchanger 20 is reduced.

If the heating capacity of the geothermal heat exchanger 10 appears to be substantially lowered, the controller 60 opens the openings of the valves V1 and V4 while reducing or completely closing the openings of the valves V2 and V5, thereby opening the pump P. In operation, the heat transfer fluid heated in the sewage heat exchanger 20 is transferred to the first heat exchange means 32. Then, the heating capacity that has been degraded by the geothermal heat exchanger 10 may be improved again.

When the cooling mode is selected, the flow direction of the refrigerant discharged from the compressor 36 becomes opposite to that of heating, and as shown in FIG. 3, the first heat exchange means 32-swelling valve 38-first Two heat exchange means 34-circulation through the path of the compressor (36).

That is, unlike when heating, the function is changed so that the first heat exchange means 32 serves as a condenser, and the second heat exchange means 34 performs a role as an evaporator.

Therefore, the heat transfer fluid having the heat energy absorbed by the geothermal heat exchanger 10 and the sewage heat exchanger 20 is deprived of heat energy from the high temperature and high pressure refrigerant while passing through the first heat exchange means 32.

The refrigerant, thus deprived of heat energy, passes through the expansion valve 38 so that the pressure drops, and the second heat exchange means 34 exchanges heat with the indoor air to cool the indoor air, and the refrigerant evaporates to become a gaseous refrigerant.

In addition, the gaseous refrigerant is sucked and compressed by the compressor 36 and sent to the first heat exchange means 32 to repeat the above cycle.

That is, during the cooling operation, the heat energy of the heat transfer fluid of the heat exchanger (10) (20) is transferred to the refrigerant of the heat pump (30), and the refrigerant circulates to perform cooling while continuing to change the condensation, expansion, evaporation, and compression. do.

As the cooling action is performed, the heat transfer fluid returns to the geothermal heat exchanger 10 and the sewage heat exchanger 20, and repeats the above operation. In this process, if the heat exchange capacity of the geothermal heat exchanger 10 is lowered, the heating system changes to a system using heat energy of the sewage heat exchanger 20 as in heating.

When the heating and cooling of the geothermal heat exchanger 10 and the sewage heat exchanger 20, the distribution unit 40 is controlled by the control of the control unit 60 to supply any one heat source to the heat pump 30 alone or multiple It is supplied by the air conditioner for optimal cooling and heating.

As described above, the heat pump system using the geothermal heat according to the present invention as the main heat source and the sewage heat as the auxiliary heat source can use both the geothermal heat and the sewage heat in parallel to perform efficient cooling and heating. It is possible to minimize the maintenance and operation costs of the heating and cooling system since no additional cost is required to operate the system.

Claims (5)

A geothermal heat exchanger installed in the ground and having a heat transfer fluid absorbing heat in the ground; A sewage heat exchanger configured to collect a heat source included in domestic sewage or waste water, and comprising a pipe connection selectively sharing the heat transfer fluid of the geothermal heat exchanger; A heat pump that stores heat transfer fluid regenerated from the geothermal heat exchanger and / or sewage heat exchanger, receives a heat transfer fluid when the pump is operated, performs heat exchange with the heat transfer fluid, and supplies heat exchanged heat energy to a place of use; A heat pump system using a complex heat source comprising a control means for enabling the two heat exchangers to be used selectively or simultaneously. The heat pump system of claim 1, wherein when the thermal energy of the heat transfer fluid heat-exchanged in the geothermal heat exchanger does not reach the heat source required by the heat pump, the thermal energy of the sewage heat exchanger is supplied to the heat pump. The heat pump system according to claim 1, wherein the heat source of the geothermal heat exchanger is used as the main heat source and the heat source of the sewage heat exchanger is used as the auxiliary heat source. The heat pump system according to claim 1, wherein the geothermal heat exchanger and the sewage heat exchanger are connected in series or in parallel. The heat pump system according to claim 1, wherein the geothermal heat exchanger and the sewage heat exchanger are each provided with a temperature sensor or a heat sensing sensor, and the signals detected by the sensors are transferred to a control unit to perform optimal cooling and heating.