JP7357324B2 - Multi-source heat pump equipment - Google Patents

Description

The present invention relates to a multi-source heat pump device that uses water such as air and groundwater as a heat source for collecting and dissipating heat, and more specifically, it relates to a multi-source heat pump device suitable for greenhouse horticulture.

In recent years, fuel prices have tended to rise as fossil fuel reserves have decreased. Under these circumstances, the introduction of air source heat pumps is being promoted as an alternative technology to fuel-based heaters, but the reality is that their introduction has not progressed very much.

One of the reasons for this is that when heating operation is performed when the outside temperature is low, frost forms on the heat exchanger of the outdoor unit, reducing the heat extraction efficiency or COP (Coefficient of Performance). . In particular, the heating load on gardening facilities is highest from nighttime to dawn when the outside temperature is lowest, so the COP is lower than that of air source heat pumps for homes/buildings and industrial use.

Additionally, if frost forms on the outdoor heat exchanger, a defrost operation will be performed using the outdoor heat exchanger as a condenser and the indoor heat exchanger as an evaporator. While the supply is stopped, only electricity is consumed and does not contribute to heating. In addition, there are few specialized equipment developed for greenhouse horticulture, and the initial installation cost is high, which is also hindering its widespread use.

On the other hand, a ground source heat pump, which is one type of water source heat pump, can efficiently collect heat from underground or groundwater even in extremely cold weather (see, for example, Patent Documents 1 and 2).

However, excavation and boring are required to bury the heat exchanger, and the construction cost for burying the heat exchanger is high, and the cost also varies depending on the soil quality and groundwater situation in the area, which is a consideration when considering capital investment. As a result, the technology has not been disseminated or implemented in society.

In addition, conventional ground source heat pumps need to drive a pump to circulate brine, which transfers heat between the heat pump and a heat source such as underground or groundwater, which reduces the overall system COP of the heat pump. This is a contributing factor.

Japanese Patent Application Publication No. 2006-145059 Japanese Patent Application Publication No. 2009-036415

Therefore, an object of the present invention is to provide a multi-heat source heat pump device that uses water such as air and groundwater as a heat source for heat collection and heat radiation, and is capable of optimizing operation according to outside air temperature, water temperature, etc., especially for greenhouse horticulture. The object of the present invention is to provide a multi-source heat pump device suitable for use.

In order to solve the above problems, the present invention includes a refrigeration cycle in which a compressor for compressing a refrigerant, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are connected via refrigerant piping, By switching the valves, the outdoor heat exchanger acts as a condenser and the indoor heat exchanger acts as an evaporator during cooling operation, and the indoor heat exchanger acts as a condenser and the outdoor heat exchanger acts as an evaporator during heating operation. In a multi-heat source heat pump device suitable for greenhouse horticulture, which uses water such as air and groundwater as a heat source for heat collection and heat radiation,
The outdoor heat exchanger has two heat exchangers, a first outdoor heat exchanger and a second outdoor heat exchanger, and the first outdoor heat exchanger is an open-loop water storage system in which water such as groundwater is stored. This is an open-loop type water-refrigerant direct expansion type heat exchanger that is immersed in water in a tank and heat exchange is performed between the water and the refrigerant, and the second outdoor heat exchanger has a blower fan. an air-refrigerant heat exchanger having
The first outdoor heat exchanger and the second outdoor heat exchanger are connected in parallel to the refrigerant pipe, and one of the first outdoor heat exchanger and the second outdoor heat exchanger Or, both are equipped with a switching valve that allows the above refrigerant to flow .
When defrosting frost adhering to the second outdoor heat exchanger during heating operation in which the indoor heat exchanger is used as a condenser and the second outdoor heat exchanger is used as an evaporator, the compressor is used as the indoor heat exchanger. A part of the high-temperature, high-pressure gas refrigerant supplied to the second outdoor heat exchanger is caused to flow through the first branch pipe to the second outdoor heat exchanger, and the second outdoor heat exchanger is used as a condenser together with the indoor heat exchanger,
The refrigerant condensed (radiated heat) and liquefied in the second outdoor heat exchanger reaches the upstream side of the expansion valve via the second branch pipe, where it condenses (radiates heat) and liquefies in the indoor heat exchanger. The refrigerant is combined with the refrigerant and the pressure is lowered by the expansion valve, and then evaporated in the first outdoor heat exchanger to become a low-pressure gas refrigerant, which is returned to the compressor via the accumulator,
By using the first outdoor heat exchanger as an evaporator instead of the second outdoor heat exchanger, the amount of high-temperature and high-pressure gas refrigerant supplied to the indoor heat exchanger is controlled by the first branch pipe. Although the amount of frost that is supplied to the second outdoor heat exchanger is reduced by the amount supplied to the second outdoor heat exchanger via the heating operation, the frost that has adhered to the second outdoor heat exchanger can be defrosted without interrupting the heating operation.
After defrosting, the heating operation state is returned to the original state before the start of defrosting using the second outdoor heat exchanger as an evaporator.

The present invention also includes the first outdoor heat exchanger, the above-mentioned A first operation mode in which either one of the second heat exchangers is used, and a second operation in which the first outdoor heat exchanger and the second outdoor heat exchanger are used together by adjusting the opening degree of the switching valve. This also includes an embodiment having a mode.

According to the present invention, since the water-refrigerant heat exchanger (first outdoor heat exchanger) is immersed in the water storage tank, the construction cost is lower than that of the closed-loop method. Heat exchange efficiency can be increased by using flowing water inside the tank.

In addition to the water-refrigerant heat exchanger (first outdoor heat exchanger), it is further equipped with an air-refrigerant heat exchanger (second outdoor heat exchanger) having a blower fan, and these heat exchangers can be selectively operated. Since it can be used, it is possible to optimize the operation according to the water temperature, outside temperature, etc.

Further, according to the defrosting means, it is possible to defrost the frost attached to the air-refrigerant heat exchanger (second outdoor heat exchanger) while continuing the heating operation.

FIG. 1 is a schematic diagram showing a first embodiment of a multi-source heat pump device according to the present invention. The schematic diagram which shows a water storage tank and an outdoor heat exchanger in the said embodiment. FIG. 2 is a plan view showing a counter-flow type water-refrigerant heat exchanger. The schematic diagram which shows the multi-heat source heat pump apparatus provided with the defrosting means as 2nd Embodiment of this invention.

Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2, but the present invention is not limited thereto.

As shown in FIG. 1, the multi-source heat pump device 1 according to this embodiment includes an outdoor unit 10 on the heat source side and an indoor unit 20 on the usage side. In this embodiment, the indoor unit 20 is assumed to be installed in a cultivation house of a horticultural facility such as an agricultural facility, but it may also be installed in a normal residential house or building, or a factory facility for industrial use. .

The outdoor unit 10 basically includes a compressor 110 that compresses refrigerant, a four-way valve 120, an outdoor heat exchanger 130, an expansion valve 140, and an accumulator 150. For example, HFO mixed refrigerants such as R410A, R32, and R452B may be used as the refrigerant.

The indoor unit 20 is basically provided with an indoor heat exchanger 210 and an indoor blower 211. Note that when performing floor heating or the like, the indoor heat exchanger 210 is placed in a hot water tank (not shown). The outdoor unit 10 and the indoor unit 20 are connected via a liquid side pipe 2 and a gas side pipe 3.

During cooling operation, the four-way valve 120 is switched to the state shown by the solid line in the figure, and the high-temperature, high-pressure gas refrigerant generated by the compressor 110 is sent to the outdoor heat exchanger 130, where it exchanges heat with, for example, outside air. After being condensed and reduced in pressure to a predetermined level by the expansion valve 140, it is evaporated by exchanging heat with the indoor air in the indoor heat exchanger 210, becoming a low-temperature, low-pressure gas refrigerant that is sent to the accumulator via the four-way valve 120. 150, and is sucked into the compressor 110 again.

During heating operation, the four-way valve 120 is switched to the state shown by the dashed line in the figure, and the high-temperature, high-pressure gas refrigerant generated by the compressor 110 is sent to the indoor heat exchanger 210, where it is exchanged with indoor air and heat. It is exchanged and condensed, passes through the expansion valve 140, exchanges heat with the outside air in the outdoor heat exchanger 130, evaporates, becomes a low-temperature, low-pressure gas refrigerant, passes through the four-way valve 120, reaches the accumulator 150, and is reused in the compressor. 110 is inhaled.

In this way, during cooling operation, the outdoor heat exchanger 130 acts as a condenser (radiator) and the indoor heat exchanger 210 acts as an evaporator (heat collector), whereas during heating operation, the outdoor heat exchanger 130 acts as an The vessel 130 acts as an evaporator (heat collector), and the indoor heat exchanger 210 acts as a condenser (radiator).

According to this embodiment, the outdoor heat exchanger 130 includes two outdoor heat exchangers, a first outdoor heat exchanger 131 and a second outdoor heat exchanger 132.

The first outdoor heat exchanger 131 is an open-loop water-refrigerant direct expansion type heat exchanger, and is immersed in a water storage tank 160, as shown in FIG. The second outdoor heat exchanger 132 is a normal air-refrigerant heat exchanger with a blower fan 133.

The first outdoor heat exchanger 131 and the second outdoor heat exchanger 132 are connected in parallel to the liquid side pipe (liquid side refrigerant pipe) 2, and are connected to the branch flow path 2a on the first outdoor heat exchanger 131 side. A solenoid valve 135 as an on-off valve is attached, and a solenoid valve 136 as an on-off valve is attached to the branch flow path 2b on the second outdoor heat exchanger 132 side.

In this embodiment, the water storage tank 160 is a water storage tank installed on the ground surface, and underground water (well water) is pumped up through a water supply pipe 161 having a pump P1. In order for the stored water to flow from the bottom to the top within the water tank 160, it is preferable that the tip of the water supply pipe 161 be drawn into the bottom of the water tank 160. You can also pull it in from Further, the water storage tank 160 is provided with a drain pipe 162 for draining overflow water.

The first outdoor heat exchanger 131 functions as a water-refrigerant heat exchanger by having its refrigerant pipe (copper pipe also called path) 131a immersed in the water storage tank 160. Fins may be attached to the refrigerant pipe 131a to be immersed. For example, it may be dipped in a spirally wound state instead of in a zigzag shape.

A pipe made of a material other than copper may be used for the refrigerant pipe 131a, but in any case, the refrigerant pipe 131a may be made of a corrosion-resistant metal material, a corrosion-resistant paint (for example, a general It is preferable to use piping coated with an epoxy resin paint (used for lining the inside and outside surfaces of metal pipes) or piping coated with corrosion-resistant polyethylene resin, for example.

As shown in FIG. 2, an air supply pipe 165 having a plurality of air jet holes 166 is arranged in the pipe wall on the end side in the water storage tank 160, and air is sent into the air supply pipe 165 from the blower P2. It is preferable to eject air from the air ejection holes 166 to promote convection of the stored water. In this case, it is preferable that the end side of the air supply pipe 165 where the air jet hole 166 is provided is arranged along the bottom of the water tank 160.

For example, a propeller-shaped stirring blade may be provided in the water tank 160 instead of the air supply pipe 165 or together with the air supply pipe 165.

As another aspect, as shown in FIG. 3 (a plan view of the water tank 160), a zigzag waterway is formed in the water tank 160 by partition plates 167 (three partition plates in this example), and the waterway is The refrigerant pipes 131a of the first outdoor heat exchanger 131 are arranged in a zigzag pattern along the line, so that the flow direction of water in the water channel (solid line arrow) and the flow direction of the refrigerant in the refrigerant pipe 131a (chain line arrow) are opposite to each other. The water-refrigerant heat exchange efficiency can also be increased by creating counter-flows.

Alternatively, a water temperature sensor may be provided to drive the water pump P1 so that the water temperature falls within a predetermined temperature range. The water tank 160 may be an excavated reservoir or the like, and the water for heat exchange may be well water, river water, industrial wastewater, agricultural water, or the like.

The compressor 110 is preferably a variable speed compressor controlled by an inverter, and its rotational speed is adjusted according to the amount of heat exchanged by the first outdoor heat exchanger (water-refrigerant heat exchanger) 131 in the water storage tank 160. It's good to be controlled.

When using the first outdoor heat exchanger 131 during cooling or heating operation, the solenoid valve 135 is opened and the solenoid valve 136 is closed. On the other hand, when using the second outdoor heat exchanger 132, the solenoid valve 136 is opened and the solenoid valve 135 is closed.

Whether to use the first outdoor heat exchanger 131 or the second outdoor heat exchanger 132 is determined by the outside air temperature, water temperature, heating or cooling capacity required by the user, etc. , 136 can be adjusted to use the first outdoor heat exchanger 131 and the second outdoor heat exchanger 132 together.

Next, according to the second embodiment, in an embodiment including the first outdoor heat exchanger (water-refrigerant heat exchanger) 131 and the second outdoor heat exchanger (air-refrigerant heat exchanger) 132, heating operation is performed. When frosting occurs on the second outdoor heat exchanger 132, defrosting can be performed without stopping the heating operation.

Therefore, as shown in FIG. 4, in addition to the above configuration (the configuration in FIG. 1), two first and second branch pipes 4, 5 and three electromagnetic valves 137, 138, 139 are used. In the following description, upstream and downstream are based on the flow direction of the refrigerant during heating operation.

First, one end of the first branch pipe 4 is connected to the gas side pipe 3. The other end of the first branch pipe 4 is connected to one end 132a of the branch flow path 2b on the second outdoor heat exchanger 132 side on the upstream side of the second outdoor heat exchanger 132. Let P be the connection point. The first branch pipe 4 is provided with a solenoid valve 137.

Next, one end of the second branch pipe 5 is connected between the other downstream end 132b of the second outdoor heat exchanger 132 and the solenoid valve 136 in the branch flow path 2b on the second outdoor heat exchanger 132 side. connected to. Let Q be the connection point. The other end of the second branch pipe 5 is connected to a piping portion of the liquid side piping 2 on the upstream side of the expansion valve 140. Let R be the connection point. The first branch pipe 5 is provided with a solenoid valve 138 .

Further, in the branch flow path 2b on the second outdoor heat exchanger 132 side, a solenoid valve 139 is provided between the connection point P and the expansion valve 140.

During heating operation using the second outdoor heat exchanger (air-refrigerant heat exchanger) 132, the four-way valve 120 is switched to the state shown by the chain line in the figure, the solenoid valves 136 and 139 are opened, and the solenoid valves 135 and 137 are opened. , 138 are closed.

During this heating operation, as described above, the indoor heat exchanger 210 serves as a condenser (radiator) and the second outdoor heat exchanger 132 serves as an evaporator (heat collector). Frost formation (frosting) is likely to occur on the second outdoor heat exchanger 132. As frost builds up, the air-refrigerant heat exchange efficiency decreases.

Therefore, defrosting is performed, and in this embodiment, among the solenoid valves 135 to 139, solenoid valves 135, 137, and 138 are opened, and the remaining solenoid valves 136 and 139 are closed.

As a result, a portion of the high-temperature, high-pressure gas refrigerant generated in the compressor 110 and directed to the indoor heat exchanger 210 flows to the second outdoor heat exchanger 132 via the first branch pipe 4, so that defrosting is performed. It will be done.

The refrigerant condensed (radiated heat) and liquefied in the second outdoor heat exchanger 132 reaches the connection point R on the upstream side of the expansion valve 140 via the second branch pipe 5, and there, it is transferred to the indoor heat exchanger 210. It condenses (radiates heat) and joins with the liquefied refrigerant, and after the pressure is lowered by the expansion valve 140, it evaporates in the first outdoor heat exchanger (water-refrigerant heat exchanger) 131 and becomes a low-pressure gas refrigerant, which is then transferred to the accumulator 150. is returned to the compressor 110.

As described above, according to the embodiment shown in FIG. Although the amount is reduced by the amount supplied, the frost adhering to the second outdoor heat exchanger 132 can be defrosted without interrupting the heating operation.

After defrosting, the solenoid valves 135, 137, and 138 are closed and the solenoid valves 136 and 139 are opened to return to the original heating operation state before the start of defrosting using the second outdoor heat exchanger 132 as an evaporator. However, depending on the case, only the solenoid valve 135 may be opened, the remaining solenoid valves 136, 137, 138, and 139 may be closed, and the heating operation may be continued using the first outdoor heat exchanger 131 as an evaporator.

During cooling operation, the solenoid valves 137 and 138 are closed and the solenoid valve 139 is open, and the solenoid valves 135 and 136 are closed depending on whether the first outdoor heat exchanger 131 or the second outdoor heat exchanger 132 is used. Opening/closing controlled. Note that opening and closing of these solenoid valves is controlled by a control section (not shown).

From the above explanation, by introducing the multi-source heat pump device of the present invention in horticultural facilities such as greenhouses and solar-based plant factories, it is possible to take advantage of the advantages of air-source heat pumps while also providing a By switching to an open-loop direct expansion type heat pump, it is possible to stably collect heat to overcome the disadvantage of frost formation on the outdoor heat exchanger.

In addition, it is possible to significantly reduce the equipment and operating costs of the water source heat pump and to maximize the COP. Furthermore, it can be expected to spread not only to the agricultural field but also to homes, buildings, industrial fields, etc.

1 Multi-heat source heat pump device 2 Liquid side piping 2a, 2b Branch flow path 3 Gas side piping 10 Outdoor unit 110 Compressor 120 Four-way valve 130 Outdoor heat exchanger 131 First outdoor heat exchanger (water-refrigerant direct expansion heat exchanger )
132 Second outdoor heat exchanger (air-refrigerant heat exchanger)
135, 136, 137, 138, 139 Solenoid valve 140 Expansion valve 150 Accumulator 160 Water tank 20 Indoor unit 210 Indoor heat exchanger

Claims (2)

The refrigeration cycle includes a compressor that compresses refrigerant, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger connected via refrigerant piping.By switching the four-way valve, the outdoor heat is transferred during cooling operation. The exchanger acts as a condenser and the indoor heat exchanger acts as an evaporator, and during heating operation, the indoor heat exchanger acts as a condenser and the outdoor heat exchanger acts as an evaporator. In a multi-source heat pump device suitable for greenhouse horticulture as a heat source for heat and heat radiation,
The outdoor heat exchanger has two heat exchangers, a first outdoor heat exchanger and a second outdoor heat exchanger, and the first outdoor heat exchanger is an open-loop water storage system in which water such as groundwater is stored. This is an open-loop type water-refrigerant direct expansion type heat exchanger that is immersed in water in a tank and heat exchange is performed between the water and the refrigerant, and the second outdoor heat exchanger has a blower fan. an air-refrigerant heat exchanger having
The first outdoor heat exchanger and the second outdoor heat exchanger are connected in parallel to the refrigerant pipe, and one of the first outdoor heat exchanger and the second outdoor heat exchanger Or, both are equipped with a switching valve that allows the above refrigerant to flow .
When defrosting frost adhering to the second outdoor heat exchanger during heating operation in which the indoor heat exchanger is used as a condenser and the second outdoor heat exchanger is used as an evaporator, the compressor is used as the indoor heat exchanger. A part of the high-temperature, high-pressure gas refrigerant supplied to the second outdoor heat exchanger is caused to flow through the first branch pipe to the second outdoor heat exchanger, and the second outdoor heat exchanger is used as a condenser together with the indoor heat exchanger,
The refrigerant condensed (radiated heat) and liquefied in the second outdoor heat exchanger reaches the upstream side of the expansion valve via the second branch pipe, where it condenses (radiates heat) and liquefies in the indoor heat exchanger. The refrigerant is combined with the refrigerant and the pressure is lowered by the expansion valve, and then evaporated in the first outdoor heat exchanger to become a low-pressure gas refrigerant, which is returned to the compressor via the accumulator,
By using the first outdoor heat exchanger as an evaporator instead of the second outdoor heat exchanger, the amount of high-temperature and high-pressure gas refrigerant supplied to the indoor heat exchanger is controlled by the first branch pipe. Although the amount of frost that is supplied to the second outdoor heat exchanger is reduced by the amount supplied to the second outdoor heat exchanger via the heating operation, the frost that has adhered to the second outdoor heat exchanger can be defrosted without interrupting the heating operation.
After defrosting, the multi-heat source heat pump device is returned to the original heating operation state before the start of defrosting, using the second outdoor heat exchanger as an evaporator. Depending on the outside temperature, the water temperature of the water in the water storage tank, and/or the heating or cooling capacity requested by the user of the indoor heat exchanger, either the first outdoor heat exchanger or the second heat exchanger is selected. a first operation mode in which one of the switching valves is used; and a second operation mode in which the first outdoor heat exchanger and the second outdoor heat exchanger are used together by adjusting the opening degree of the switching valve. The multi-source heat pump device according to claim 1 , characterized in that:

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