JP3197464U - Combined heat pump system - Google Patents

Abstract

A heat pump device that controls a thermodynamic cycle responsible for the work of supplying a heat source of a predetermined temperature using geothermal heat, and a heat pump device (an air conditioner, which is controlled separately using the heat source) Provided is a composite heat pump system in which a water heater and the like are thermally connected after heat exchange. Heat medium gas is circulated through a pipe line 1 installed in the underground part, and the underground pipe line 1 is used as a heat exchanger to exchange heat with underground heat to evaporate or condense, thereby exchanging heat in the ground part. In the terminal 2, the electric compressor 3 is inverter-controlled to circulate the heat medium so that a predetermined temperature can be supplied as a heat source of separate heat pump devices 4 and 6 which are independent of control. [Selection] Figure 1

Description

  The present invention relates to a heat pump system using ground heat that circulates a heat medium gas through a pipe installed in the underground and evaporates or condenses the heat medium gas by underground heat.

  Heat pump devices that perform air conditioning, refrigeration, and hot water supply using condensation or evaporation of heat transfer medium gas (such as CFCs) have a ratio of energy (hot / cold heat) that can be taken out to the input energy (compressor power, etc.) (Coefficient of performance) has been improved by improvements in various elemental technologies in recent years, and its introduction in various fields is progressing due to its energy saving.

  In the heat pump device, the heat medium gas after heat utilization is sent by a compressor to compensate for the change in enthalpy, and is exchanged with other heat sources (for example, gasified after using a cooling indoor unit (evaporator)). The heat medium is circulated after being exchanged with the outside air temperature in the outdoor unit (condenser).

  For this reason, heat pump devices are an important factor that affects the effectiveness of their compatibility with heat exchange sources (heat sources such as air heat, water heat, underground heat, and solar heat) that are external energy sources. In heat pump devices, seasonal changes in the outside air temperature adversely affect heat exchange (the outside air temperature is high during the cooling period and the outside air temperature is low for the heater), which is an inevitable constraint for improving the efficiency of the heat pump device. ing.

  On the other hand, a heat pump system with higher efficiency than a heat pump device using an air-cooled heat source at an outside temperature can be realized by using underground heat or groundwater with little temperature change throughout the year as a heat exchange source.

The technical idea of installing a heat medium circulation pipe in the ground, exchanging heat between the heat medium and the ground heat, and using the heat of the heat medium gas after the heat exchange as a heat pump heat source is disclosed in Patent Literature 1 to Patent Document 3 and the like.
Japanese Patent Laid-Open No. 10-300266 JP 2009-257737 A JP 2011-7476 A

  Patent Document 1 discloses a method in which a liquid heat medium called brine is subjected to heat exchange by underground heat and sensible heat, the liquid heat medium is circulated and pumped to the ground by a pump, and is used as a heat source for the heat pump. In this case, since sensible heat exchange is performed at a ground temperature of approximately 10 ° C. to 15 ° C. in this case, a temperature difference between the ground heat and the brine is necessary, and in order to increase the heat exchange amount, a liquid heat medium In order to circulate a sufficient amount, a larger pump power is required, resulting in a decrease in efficiency of the heat pump system.

  In addition, as described in paragraph 0011 of Patent Document 1, groundwater itself is pumped and used as a heat source, or groundwater around the underground heat collection pipe is pumped up to improve heat exchange with the piping heat medium. There are also known methods for doing this, but there are significant practical problems such as requiring dedicated equipment and power for that purpose.

  On the other hand, in Patent Document 2 and Patent Document 3 described above, the heat medium gas circulating in the heat pump system is directly circulated to the underground part by underground piping, and the heat medium gas is directly expanded or condensed in the underground part. It is related to the system and does not require special equipment or power to pump and circulate brine or groundwater, and evaporates and condenses with a temperature difference smaller than sensible heat exchange by latent heat exchange to increase heat utilization efficiency and heat medium Since the compression ratio of gas can be reduced, it is an excellent geothermal heat pump system that can be more efficient than a sensible heat exchange system such as brine.

  However, in any of the patent documents, although the direct expansion method is concerned, the heat medium gas flow path connects the ground part and the underground part in one system, and the heat medium in the underground pipe by one compressor. While controlling the expansion or condensation of gas, it is circulated to meet the heat demand in heat exchangers such as air conditioners on the ground, and as a thermodynamic cycle of one heat medium gas by a long heat medium pipe A dedicated heat pump system has been designed in consideration of the remarkable individuality of environmental conditions such as the status of underground heat, the installation of sampling wells, and the heat demand on the ground. I had to design and build.

  Furthermore, technically, in order to raise the heat medium gas in the vicinity of the underground heat temperature zone to the heat medium gas inlet temperature of the heat exchanger such as an air conditioner, the input of the compressor becomes large, A change in the state of the gas liquid (temperature increase due to friction or the like) caused an entropy increase more than necessary, and the work volume of the entire heat pump system increased = efficiency decreased.

Means to solve the problem

  The inventor of the present application is based on the effectiveness of the direct expansion type (underground latent heat exchange type) in which the heat medium gas is circulated in the underground, and the rigidity of the above-described known technology in the device design and the heat of one system We have eagerly studied how to overcome the limitations of the mechanical cycle system, and connected the heat pump device used on the ground and the heat pump device used for underground heat through a heat exchanger, We have found a method of controlling gas control with independent control circuits and compressors.

  That is, the invention of claim 1 of the present application circulates a heat medium gas through a pipe line installed in the underground part, evaporates or condenses by exchanging heat with underground heat using the underground pipe line as a heat exchanger, In the heat exchange terminal, a combined heat pump system is characterized in that an electric compressor is inverter-controlled to circulate the heat medium so that a predetermined temperature can be supplied as a heat source of a separate heat pump device with independent control. .

  Further, in the invention of claim 2, the inverter control detects the temperature of the main body of the heat exchange terminal or the heat medium gas outlet pressure from the heat exchange terminal with a sensor, and the temperature or pressure is within a predetermined upper and lower limit range. The composite heat pump system according to claim 1, wherein the operation of the compressor is adjusted by the frequency so as to be inside.

  Further, in the invention of claim 3, the heat exchange terminal is divided into a plurality of sub chambers on the heat exchange side, and the heat medium pipes of a plurality of separate heat pump devices independently controlled are respectively connected to the sub chambers. The composite heat pump system according to claim 1, wherein the composite heat pump system is an evaporator or a condenser of a plurality of separate heat pump devices.

  With the above configuration, the heat medium gas is exchanged with a ground heat temperature zone (approximately 10 ° C. to 15 ° C.) and a root to perform a work to obtain a predetermined heat source temperature zone (18 ° C. to 22 ° C.) on the ground. The required heat zone of the heat exchanger such as an air conditioner in the use facility using the heat of the geothermal heat pump to be performed and the heat source temperature zone (18 ° C. to 22 ° C.) of the heat exchange terminal (approximately 36 ° C. at the time of heating) It is possible to make a combined system with a heat pump device that is independent of the control of the heat pump that uses geothermal heat that works to 50 ° C. or approximately 7 ° C. to 15 ° C. during cooling.

Effect of device

  The device of the present application enables the heat source to be supplied to the ground part within the range of variable capacity by inverter control when using the underground heat directly in the expansion type, and ensures a margin in the capacity design of the heat exchange terminal. Then, it is possible to respond more stably and flexibly to fluctuations in the control of a separate heat pump device on the ground and to the start and stop of a plurality of heat pump devices connected in parallel.

  In addition, the inverter-type heat pump device that is controlled to use geothermal heat as a heat source on the ground and the heat pump device on the ground are separated from each other, so that the device for using ground heat can be used. The design can be simplified or rated, and the heat pump device on the ground is only required to secure the connection of the heat medium gas system to the heat exchange terminal. It is possible to easily use a general machine such as an air conditioner device to form a composite system.

  Furthermore, it is possible to connect and increase the number of heat pump devices on the ground as appropriate by providing sufficient capacity to the heat pump device for use of underground heat within a reasonable range.

  Embodiments of the present invention will be described.

  In the present invention, the heat transfer medium gas is circulated by a compressor under inverter control in a heat collecting tube inserted in a reciprocating manner in the heat collecting well, and the ground heat is once set in a predetermined temperature zone to be a supply heat source at the heat exchange terminal. Therefore, the thermodynamic cycle of the heat medium gas is designed and controlled based on the heat medium gas circulating between the underground heat collecting tube and the heat exchange terminal. Here, for convenience, it is referred to as a “first stage heat pump”.

  In the first stage heat pump, the temperature of the heat exchange terminal body or the heat medium gas outlet pressure of the heat exchange terminal is detected by a sensor, and the electric compressor is inverter-controlled so that the heat exchange terminal is in a predetermined temperature range. is there.

  Next, a separate heat pump device in which the heat medium system is connected to the heat exchange terminal of the first stage heat pump and the control is independent of the thermodynamics of the heat medium gas independent of the first stage heat pump using the heat exchange terminal as a heat source. The inverter is controlled based on the cycle. Here, the heat pump thermally connected to the first stage heat pump is referred to as a “second stage heat pump” for convenience.

Therefore, the composite heat pump of the present invention means that the first stage heat pump using the above ground heat and the second stage heat pump such as a general air conditioner are “heat medium gas” by a heat exchange terminal (heat exchanger). It is connected to perform heat exchange with “heat medium gas”, and is controlled by temperature or pressure conditions set separately (FIG. 1).

  The heat exchange terminal may be a known heat exchanger as long as it has a structure capable of withstanding high pressure (1 MPa to several MPa) due to evaporation / condensation, such as a plate heat exchanger or a double tube heat exchanger. Etc. may be selected. In this case, in principle, the heat medium gas of the first stage heat pump and the second stage heat pump is subjected to heat exchange, and a reverse phase change is generated in the heat exchanger, one of which is evaporation and the other is condensation.

  In heat exchange terminals (heat exchangers), it is desirable in terms of heat exchange efficiency that the heating medium and the cooling medium flow in contact with each other in terms of heat exchange efficiency, but the temperature difference in the heat exchange terminals (heat exchangers) It becomes larger on the medium inlet side and outlet side. Therefore, in this application, the temperature of the main body of the heat exchange terminal is set by installing the heat sensor detection unit in close contact with any part on the outer surface side of the main body of the heat exchange terminal, preferably in the vicinity of the middle part of the heat medium inlet / outlet part. Is to be measured.

  The “predetermined temperature supply” described in claim 1 of the present application means that the temperature of the main body of the heat exchange terminal is detected and the temperature change is compensated by adjusting the amount of heat medium circulation in the compressor by inverter control. This is to maintain a predetermined temperature. Naturally, when there is a sudden change in the heat exchange load due to the second stage heat pump, the temperature of the heat exchange terminal changes, and the compressor is operated accordingly. .

  In the present invention, the predetermined temperature supplied at the heat exchange terminal by the first stage heat pump is generally in the subsurface heat temperature zone (about 10 ° C. to about 15 ° C.) in relation to the work of the second stage heat pump. A temperature zone approximately in the middle of a temperature of approximately 32 ° C. to 35 ° C. which is the lower limit value of the demand heat temperature zone (heating) or the upper limit value of the exhaust heat temperature zone (cooling) when the eye heat pump is an air conditioner, That is, it is desirable that the predetermined temperature is determined in the range of about 18 ° C. to 22 ° C., around 20 ° C.

  Furthermore, practically, as described in the invention of claim 2 of the present application, the range of change in the temperature of the heat exchange terminal determined in advance of the heat exchange terminal is approximately ± 2 ° C. to ± 5 ° C. from the predetermined temperature. The compressor is operated by inverter control so that the temperature is kept within the range of 0 ° C., and is kept within the range of the temperature change.

  For example, when the temperature of the heat exchange terminal is set to 20 ° C., when the variation width of ± 2 ° C. of the temperature is reached, it is returned to a predetermined temperature of 20 ° C. When the temperature is set to 18 ° C., the compressor of the first stage heat pump is operated so as to return the temperature to a predetermined temperature of 18 ° C. when a change width of ± 5 ° C. is reached.

  By doing so, the control as described in the above paragraph 0027 does not cause the subtle and frequent compressor operation to maintain the predetermined temperature, and the operation of the compressor of the first stage heat pump is stopped within the range of the predetermined temperature change range. Low operation can be achieved. Of course, when the operation of the first-stage heat pump is stopped or lowered, the compressor of the second-stage heat pump operates so that the second-stage inverter-controlled heat pump compensates for the temperature change of the heat exchange terminal.

  The selection of the heat exchange terminal (heat exchanger) is not a problem when it has sufficient heat exchange efficiency and main body capacity, but there are cases where a smaller one is selected from the viewpoint of economy. The temperature difference between the outlet temperature of the heat medium gas of the first stage heat pump from the heat exchange terminal and the outlet temperature of the heat medium gas of the second stage heat pump must be selected as much as possible.

  Since the composite heat pump system of the present invention is configured by the thermal connection of the first-stage heat pump and the second-stage heat pump, the above temperature difference is preferably 6 ° C. or less in any operating condition. Must exhibit sufficient heat exchange capacity to be 2 ° C. or lower. Therefore, in practice, the upper limit of the heat exchange demand of the second stage heat pump is assumed in advance, and the rated capacity of the compressor and the rated capacity of the heat exchanger are studied so that the corresponding heat exchange capacity can be demonstrated. A first stage heat pump has been designed.

  The second stage heat pump according to claim 3 of the present application has a plurality of connections to the heat exchange terminal. The first stage heat pump side is a heat medium gas thermodynamic cycle system that circulates between the underground heat source and the heat exchange terminal. On the other hand, the second stage heat pump is composed of a thermodynamic cycle system between the heat exchange terminal and any individual heat utilization terminal (air conditioner, water heater, etc.). Each heat pump has an independent compressor and control mechanism, and is separated from other second-stage heat pumps and first-stage heat pumps in terms of thermodynamic cycle, and is only thermally connected at the heat exchange terminals. (FIG. 2).

  Therefore, the fluctuations in the heat exchange demand at the heat exchange terminals of the plurality of second stage heat pumps are summed up and become a control target related to the heat supply of the first stage heat pump. Even in this case, the compressor of the first stage heat pump is inverter-controlled so as to compensate for the temperature change of the heat exchange terminal detected by the temperature sensor arranged on the heat exchange terminal so that the temperature change range is within the above range. The amount is to be adjusted.

  Since the heat exchange side to which the second stage heat pump of the heat exchange terminal is connected (referred to as viewed from the first stage heat pump side in the present invention) is divided into a plurality of sub chambers. The inlet / outlet of the heat medium gas to the chamber is provided independently.

  In this case, for example, the heat medium gas of the first stage heat pump is branched in parallel, and a heat exchange terminal corresponding to each of the plurality of second stage heat pumps is provided, where heat exchange of the heat medium gas between the first stage heat pump and the second stage heat pump is performed. Of course, there is a method of performing this, however, in the present invention, it is necessary to install a plurality of heat exchange terminals (heat exchangers) and, accordingly, install a plurality of sensors for control. Is configured as an integral heat exchanger.

  In the composite heat pump system of the present invention, a second-stage heat pump using a heat exchange terminal as a heat source is thermally connected to a first-stage heat pump using an underground heat source, and the control of each heat pump is separated. . For this reason, the first-stage heat pump determines the operation of the second-stage heat pump based on a change in the temperature of the heat exchange terminal, and activates the first-stage heat pump.

  Since the heat exchange terminal is sufficiently insulated from the outside air temperature by the heat insulating material, the temperature change of the heat exchange terminal is due to the heat exchange demand of the second stage heat pump. For this reason, when the second stage heat pump is stopped, the temperature change of the heat exchange terminal does not occur, and at this time, the first stage heat pump is also automatically stopped.

  On the other hand, when the second stage heat pump is activated (for example, when the air conditioner is started), since a sudden heat load is applied to the heat exchange terminal, the temperature change is detected by the temperature sensor arranged on the heat exchange terminal. The eye heat pump is activated. In addition, the temperature change (Δt) per unit time (for example, per minute) is measured, the influence of the change in the normal outside air temperature is eliminated, and the start of the second stage heat pump is detected. ing.

  In the thermodynamic cycle of the heat transfer medium gas, it can be considered that the temperature and the pressure are almost synonymous indexes. Therefore, in the above description, instead of detecting the temperature change of the heat exchange terminal, the first stage heat pump, The pressure may be measured and controlled by a pressure sensor arranged at the inlet / outlet of the heat transfer medium gas to the heat exchange terminal of the stage heat pump.

  In the heat pump device, there are a case where the use of cold and heat in the final heat utilization device is fixed (water heater, refrigerator, etc.) and a case where it is switched and variable (air conditioner etc.). Usually, when switching / variable, the flow direction of the heat medium gas is reversed, and the gas state heat medium always flows through the compressor. In terms of system configuration, each of the first-stage and second-stage heat pumps is provided with a four-way switching valve in the heat medium flow path, and can be switched when using cold or hot. Although not specifically described and illustrated in the present specification, the present invention also naturally includes at least the first stage heat pump system including a flow direction switching mechanism.

  In addition, when the heat exchange capacity of the heat exchange terminal (heat exchanger) of the present invention is sufficiently secured, the temperature of the heat medium gas of the first stage heat pump can be used for slight fluctuations in the heat exchange demand of the second stage heat pump. In addition, the change of the temperature index for controlling the operation of the first stage heat pump is given by the device of claim 2 of the present invention without giving a large change to the change, thereby gradually reducing the load fluctuation of the compressor of the inverter type control of the first stage heat pump. Can be.

  For this reason, it is easier to stabilize the base load operation of the compressor for controlling the heat transfer medium gas in the underground piping that adopts the natural heat exchange system, and to give the overall design of the composite heat pump system a resilient load. Is possible.

  Furthermore, the heat medium gas of the first stage heat pump and the second stage heat pump can be selected with different characteristics, for example, select the heat medium gas of the first stage heat pump with excellent low pressure / low temperature characteristics, and more It is possible to design a thermodynamic cycle system that improves the efficiency of underground heat utilization.

  In addition, as shown in the conceptual diagram of the thermodynamic cycle of the composite heat pump system of the present invention in FIG. 3, compared with the conventional one-system geothermal heat pump cycle (broken line in the figure), the cycle of the first stage heat pump ( In the case where the cycle of the second stage heat pump (the upper part in the figure) is thermally coupled, the refrigeration capacity increases (β> α in the figure) and the work is reduced ((A + B) <in the figure) C), and the combined heat pump system of the present invention exhibits superior performance than the conventional one-cycle ground-type heat pump system on the thermodynamic cycle.

  However, in contrast to the conventional one-system cycle system, the present invention requires that the inverter-controlled compressor be operated in each of the first and second stages, and there is an aspect that power consumption increases depending on the thermal load situation. However, the heat medium in a temperature zone that is approximately between the underground heat temperature zone and the demand heat temperature lower limit value or exhaust heat temperature upper limit value of the second-stage heat pump (approximately 20 ° C. in an air conditioner). In a setting that can stabilize the heat exchange between the gases, the operating status of each compressor can be reduced, and the power consumption of the entire system can be optimized to a level that is slightly higher than the conventional type.

  Moreover, not only the direct expansion method but also a heat pump system by a conventional method such as a brine method or a groundwater cooling method, the heat source temperature zone and the heat demand temperature zone or exhaust heat temperature zone at the final heat utilization terminal When the temperature difference between the two is large (approximately around 30 ° C. or more), it is possible to increase efficiency by actively using a multi-stage thermodynamic cycle with the composite heat pump system of the present invention.

  In any case, in the heat pump using geothermal heat, the heat pump device that controls the thermodynamic cycle responsible for the work of supplying the heat source at a predetermined temperature using the geothermal heat, and the heat source as a separate body A heat pump device (air conditioner, water heater, etc.) to be controlled constitutes a combined heat pump system that is thermally connected after heat exchange between heat medium gas and heat medium gas at a heat exchange terminal (heat exchanger) Needless to say, the matters relating to the technical idea are included in the scope of the present invention even if they include partial use of a known technique.

  Conceptual diagram showing the composite heat pump system of the present invention   Conceptual diagram of an embodiment of the heat pump system according to claim 3 of the present application   Conceptual diagram of thermodynamic cycle by composite heat pump of the present invention

1 Ground heat piping line 2 Heat exchange terminal 3 Compressor (first stage heat pump device)
4 Compressor (second stage heat pump device)
5 Heat sensor and inverter control device 6 Heat utilization terminal (second stage heat pump device)

Claims (3)

Heat medium gas is circulated through the pipeline installed in the underground, and the underground pipeline is used as a heat exchanger to exchange heat with underground heat to evaporate or condense, and control is independent at the heat exchange terminal on the ground. A composite heat pump system characterized in that an electric compressor is controlled by an inverter to circulate a heat medium so that a predetermined temperature can be supplied as a heat source of a separate heat pump device The inverter control detects the temperature of the heat exchange terminal main body or the heat medium gas outlet pressure from the heat exchange terminal with a sensor, and operates the compressor according to the frequency so that the temperature or pressure is within a predetermined upper and lower limit range. The composite heat pump system according to claim 1, wherein the composite heat pump system is adjusted. The heat exchange terminal is divided into a plurality of sub chambers on the heat exchange side, and the heat medium pipes of a plurality of separate heat pump devices independently controlled are connected to the sub chambers, respectively. The composite heat pump system according to claim 1, wherein the composite heat pump system is an evaporator or a condenser.

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