JP2010078285A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coolant circuit and a heat pump water heater equipped with the same having high safety, preventing spreading of fire to a coolant apparatus and burning of the coolant apparatus when leaking coolant is burned. <P>SOLUTION: The heat pump water heater includes a coolant circuit annularly connecting a compressor 1 compressing and delivering the coolant, a condenser 2 carrying out heat exchange between the coolant delivered from the compressor 1 and a load medium, an expansion valve 3 decompressing the coolant in a downstream side of the condenser 2, and an air heat exchanger 4 evaporating the coolant decompressed by the expansion valve 3, and using an inflammable coolant as the coolant. A protection device 6 discharging the coolant when a pressure of the coolant circuit becomes a design pressure or more, is provided between an outlet of the expansion valve 3 and an inlet of the compressor 1, and a cover 7 for preventing fire spreading is provided on the protection device 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat pump water heater provided with a refrigerant circuit using a combustible refrigerant.

Natural refrigerants such as carbon dioxide and hydrocarbons having a small global warming potential are used as refrigerants used in refrigerant circuits provided in refrigeration equipment such as air conditioners and refrigerators.
Among refrigeration equipment having a refrigerant circuit, many household heat pump water heaters use carbon dioxide as a refrigerant. In addition, flammable hydrocarbon-based refrigerants, like carbon dioxide, have a low global warming potential and may be used as refrigerants in the future.

Hydrocarbon refrigerants have the advantage of a low global warming potential, but on the other hand, because they are flammable, when used as refrigerants, they can be ignited by some ignition source when leaked outside the refrigerant circuit. There is a risk of burning.
Therefore, when a flammable refrigerant such as hydrocarbon is used, it is necessary to provide a safety measure for eliminating the risk that the refrigeration equipment will burn due to the combustion of the refrigerant when the refrigerant leaks.

  Therefore, in a refrigeration apparatus equipped with a refrigerant circuit using a combustible refrigerant, a relief diffusion valve capable of diffusing and releasing the refrigerant in the refrigerant circuit into the atmosphere while changing the discharge direction is installed, and there is no risk that the leaked refrigerant will burn. Such a refrigeration apparatus has been proposed (see, for example, Patent Document 1).

  There is also a refrigeration device that includes a discharge unit that discharges the refrigerant out of the refrigerant circuit, and a fan that diffuses the refrigerant in the vicinity of the discharge unit (see, for example, Patent Document 2).

JP 2006-145075 A (page 3 to page 4, FIG. 1) JP 2000-97505 A (page 3 to page 5, FIGS. 1 and 2)

  When the refrigerant leaks, the refrigeration apparatus described in Patent Document 1 diffuses the leaked refrigerant by installing a relief valve that can diffuse and release, or the refrigeration apparatus described in Patent Document 2 diffuses the leaked refrigerant. However, in any case, when the refrigerant leaked from the discharge unit burns, it cannot be prevented from spreading to the refrigeration equipment and burning the refrigeration equipment.

  The present invention has been made in order to solve the above-described problem. When the refrigerant leaked from the discharge unit burns, a highly safe refrigerant circuit that spreads to the refrigeration equipment and does not burn the refrigeration equipment. It aims at providing the heat pump water heater provided.

  A heat pump water heater according to the present invention compresses and discharges a refrigerant, a condenser that exchanges heat between the refrigerant discharged from the compressor and a load medium, and decompresses the refrigerant on the downstream side of the condenser. An expansion valve and an air heat exchanger for evaporating the refrigerant decompressed by the expansion valve are connected in an annular form, and are provided with a refrigerant circuit using a combustible refrigerant as the refrigerant, and an outlet of the expansion valve and an inlet of the compressor In the meantime, a protective device for releasing the refrigerant when the pressure exceeds the design pressure of the refrigerant circuit is provided, and a protective cover is provided on the protective device.

  The heat pump hot water heater according to the present invention uses a flammable refrigerant such as hydrocarbon in a refrigerant circuit, and a protection device is provided on the refrigerant circuit so that a location where the refrigerant leaks is specified in advance. By providing a cover for preventing the spread of fire, it is possible to prevent ignition of the entire refrigeration equipment when the leaked refrigerant burns.

Embodiment 1 FIG.
FIG. 1 is a refrigerant circuit configuration diagram of a heat pump water heater according to Embodiment 1 of the present invention, and FIG. 2 is an enlarged configuration diagram of a main part of FIG.
In FIG. 1, the heat pump water heater is provided with a refrigerant circuit using a combustible refrigerant such as hydrocarbon. The refrigerant circuit includes a compressor 1 that compresses and discharges the refrigerant, a condenser 2 that exchanges heat between the refrigerant discharged from the compressor 1 and water that is a load medium circulating in the hot water supply circuit, and downstream of the condenser 2. An expansion valve 3 for decompressing the refrigerant on the side and an air heat exchanger 4 for evaporating the decompressed refrigerant are provided, which are connected in an annular shape. A blower 5 is installed on the outlet side of the air heat exchanger 4.

  In this refrigerant circuit, a protective device 6 is provided via a branch pipe in the refrigerant pipe 3 a between the outlet of the expansion valve 3 and the inlet of the compressor 1. The protection device 6 is set to operate in a range larger than the design pressure of the refrigerant circuit and smaller than the withstand pressure pressure, and the refrigerant leaks when the refrigerant pressure in the refrigerant circuit becomes larger than the design pressure. . Reference numeral 7 denotes a cover for preventing the spread of fire provided in the protective device 6 so that when the leaked refrigerant burns, it does not spread over the entire refrigeration equipment.

  Since the protection device 6 is activated when the pressure in the refrigerant circuit becomes higher than the design pressure, the refrigerant leaks, so that the refrigerant is released from the protection device 6 that is most likely to leak in the refrigerant circuit. For this reason, the location where the refrigerant leaks can be specified in advance, and the protective device 6 is provided with a cover 7 for preventing the spread of fire, so that when the refrigerant burns, it spreads throughout the refrigeration equipment. Can be prevented.

For the protective device 6, for example, a fusible stopper or a rupturable plate is used. A fusible stopper is usually a fusible alloy that melts at a certain temperature, which seals a container filled with gas. When the temperature of the container rises excessively, the fusible alloy melts and becomes a gas. To prevent accidents such as rupture of containers. Similarly, the rupture disc protects the container by rupturing and releasing the gas when the gas in the container reaches a predetermined pressure.
The protection device 6 in the present embodiment is such that the above-described fusible plug or rupture plate is provided in the refrigerant pipe 3a via a branch pipe.

  Therefore, the temperature range in which the fusible alloy melts and the fusible plug operates is set higher than the refrigerant saturation temperature at the design pressure of the heat pump water heater and lower than the refrigerant saturation temperature corresponding to the guaranteed pressure resistance. If it carries out like this, when a refrigerant | coolant leaks, since it discharge | releases from the soluble plug which is easy to discharge | release, the position where a refrigerant | coolant leaks in a refrigerant circuit can be fixed. Similarly, the pressure at which the rupturable plate bursts is higher than the refrigerant saturation temperature at the design pressure of the heat pump water heater, and lower than the refrigerant saturation temperature corresponding to the guaranteed pressure resistance.

  If the fusible plug and the rupturable plate are used at the same time, it is possible to prevent the refrigerant from being released even if the temperature of the portion where the fusible plug is installed rises locally and the fusible alloy melts. That is, when the temperature rises locally, the pressure in the refrigerant circuit of the heat pump water heater is unlikely to be higher than the design pressure, so that the burst plate can prevent the refrigerant from being released from the refrigerant circuit. Therefore, the combustible refrigerant is not released outside the heat pump water heater, and the occurrence of a combustion accident can be prevented.

  The above design pressure is a standard for determining the pressure resistance of a product, which is determined by the internal volume of the refrigerant circuit provided in the heat pump water heater, the type of refrigerant filled, the amount of refrigerant, the maximum pressure during operation of the refrigerant circuit, etc. Pressure. The guaranteed withstand pressure is a pressure at the time of performing a pressure resistance test of the product, and the product under test passes the pressure resistance test because there is no leakage, deformation, or destruction of the product.

  During operation of the heat pump water heater, the section from the outlet of the expansion valve 3 to the inlet of the compressor 1 in the refrigerant circuit is a low pressure section, and the section from the outlet of the compressor 1 to the inlet of the expansion valve 3 is a high pressure section. For this reason, the design pressure is lower in the low pressure part than in the high pressure part, and the refrigerant is more likely to leak than the low pressure part in which the design pressure is low. Therefore, it is preferable to install the protection device 6 in the low pressure part. For example, since the suction line of the compressor 1 is surely a low-pressure part during operation, the place where the refrigerant leaks can be specified by installing the protection device 6 in this part.

  As the cover 7 for preventing fire spread, a cover made of iron plate is used. Further, a fireproof paint may be applied to the inside of the cover. Further, as the material of the cover 7, a flame retardant fire spreader may be used.

Next, the operation of the present embodiment configured as described above will be described.
In the refrigerant circuit of the heat pump water heater, the heated gas refrigerant that has become high temperature and high pressure by the compressor 1 also flows into the refrigerant pipe 2a, and the water in the hot water tank (not shown) is supplied to the water pipe of the condenser 2. When passing through 2b, heat is exchanged to heat the water and reach the hot water supply tank. The refrigerant that has transferred heat to the water reaches the expansion valve 3 from the condenser 2, where the refrigerant is decompressed by the expansion valve 3, flows into the air heat exchanger 4, and absorbs heat from the outside air blown by the blower 5. The gas is evaporated and returned to the compressor 1.

  When the heat pump water heater is affected by some influence from the outside, for example, when the ambient temperature rises excessively, the refrigerant pressure in the refrigerant circuit rises, and there is a risk that the copper pipe or the like constituting the refrigerant circuit will crack. . When a crack occurs, the combustible refrigerant in the refrigerant circuit leaks to the outside.

In the present embodiment, when the refrigerant pressure in the refrigerant circuit rises and there is a risk of cracking in the copper pipe or the like constituting the refrigerant circuit, that is, when the pressure in the refrigerant circuit becomes higher than the design pressure, The device 6 is activated and the refrigerant is released from the protective device 6 which is most likely to be released in the refrigerant circuit.
Even when the refrigerant discharged from the protective device 6 burns or explodes, the protective device 6 is provided with the cover 7 for preventing the spread of fire, so that the entire refrigeration equipment can be prevented from being ignited.

Embodiment 2. FIG.
FIG. 3 is a refrigerant path configuration diagram of the heat pump water heater according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the component same as Embodiment 1, and description is abbreviate | omitted.
In this Embodiment 2, the fire extinguishing apparatus 8 which supplies water from the water piping 2b in the vicinity of the protection apparatus 6 is provided.

Next, the operation of this embodiment will be described.
The water spout of the fire extinguishing device 8 is stopped by a soluble metal. The fusible metal attached to the water spout of the fire extinguisher 8 operates at the combustion temperature of the refrigerant. When the refrigerant discharged from the protection device 6 burns, the temperature around the protection device rises, so that the soluble metal is activated and water is sprinkled from the fire extinguishing device 8. Thereby, the danger of igniting the whole heat pump water heater can further be reduced.

Embodiment 3 FIG.
FIG. 4 is a refrigerant path configuration diagram of the heat pump water heater according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the component same as Embodiment 1, and description is abbreviate | omitted.
In the third embodiment, a detection unit 9 that detects a leaked refrigerant is installed in the vicinity of the protection device 6, and a blower 10 that diffuses the leaked refrigerant is installed around the protection device 6.

Next, the operation of this embodiment will be described.
When the leaking refrigerant is detected by the detection means 9, the detection signal is sent to a control unit (not shown). When the refrigerant leaks from the protective device 6, the detection means 9 detects this, and stops this operation during the operation of the heat pump water heater in accordance with a command from the control unit. Next, the blower 10 for diffusing the leaked refrigerant installed around the protective device 6 is operated to diffuse the leaked refrigerant into the atmosphere and reduce it to a concentration at which the flammable refrigerant does not burn in the atmosphere. At this time, if the heat pump water heater is being energized, the air heat exchanger blower 5 can be operated, whereby the leaked refrigerant can be diffused into the atmosphere in a shorter time. Therefore, not only can the risk of igniting the entire heat pump water heater be reduced, but also the risk of burning the leaked refrigerant can be reduced.

  As the detection means 9, a gas sensor that reacts with a hydrocarbon gas that is a flammable refrigerant is used. If the refrigerant leaks, it evaporates, and the pipe temperature near the protective device 6 is lowered by the heat of evaporation at this time. Therefore, a temperature sensor that detects the temperature drop of the pipe may be used. In addition, when a fusible plug is used for the protective device 6, a structure may be used in which the fusible alloy portion is energized at all times, and when the fusible alloy is melted, a non-energized state may be established. Furthermore, when the refrigerant leaks, a refrigerant flow with the protective device 6 as an outlet is generated in the refrigerant circuit. Therefore, a flow meter that is installed between the refrigerant pipe 3a and the protective device 6 and detects this flow is used. May be.

Embodiment 4 FIG.
FIG. 5 is a refrigerant path configuration diagram of a heat pump water heater according to Embodiment 4 of the present invention. In addition, the same code | symbol is attached | subjected to the component same as Embodiment 1, and description is abbreviate | omitted.
In the fourth embodiment, the detection means 9 for detecting the leaked refrigerant in the vicinity of the protection device 6, the blower 10 for diffusing the leaked refrigerant in the vicinity of the protection device 6, the outlet of the compressor 1 and the expansion valve 3. In the vicinity of the inlet, there are provided first and second flow path switching valves 11 and 12 that operate when refrigerant leaked from the detection means 9 is detected.

Next, the operation of this embodiment will be described.
When the refrigerant leaks from the protective device 6, the detection means 9 detects this, and the blower 10 for diffusing the leaked refrigerant is operated according to a command from the control unit, and the leaked refrigerant is diffused into the atmosphere. At the same time, the first and second flow path switching valves 11 and 12 are operated to close the flow path from the outlet of the compressor 1 to the inlet of the expansion valve 3 to form a closed circuit. Thus, only the amount of the flammable refrigerant that has been filled from the outlet of the expansion valve 3 to the inlet of the compressor 1 is released to the atmosphere, so that the risk of a burning concentration can be reduced.

  Since the design pressure of the high-pressure part from the outlet of the compressor 1 to the inlet of the expansion valve 3 is higher than that of the low-pressure part from the outlet of the expansion valve 3 to the inlet of the compressor 1, the refrigerant is increased by the increase of the refrigerant pressure in the refrigerant circuit. If the first and second flow path switching valves 11 and 12 are installed in the low pressure section, the flow path is a closed circuit, as in the fourth embodiment. In this case, the refrigerant will not leak again.

Embodiment 5 FIG.
FIG. 6 is a refrigerant path configuration diagram of the heat pump water heater according to Embodiment 5 of the present invention. In addition, the same code | symbol is attached | subjected to the component same as Embodiment 1, and description is abbreviate | omitted.
In the fifth embodiment, a detection unit 9 that detects a leaked refrigerant in the vicinity of the protection device 6, a blower 10 that diffuses the leaked refrigerant around the protection device 6, a detection unit 9 and a blower 10 for refrigerant diffusion. In addition, an independent power source 13 such as a battery or a dry cell for supplying power is provided, and power is supplied by a power source different from the power supplied to the heat pump water heater.
When the refrigerant leaks from the protective device 6 by the independent power source, the leakage is detected by the detecting means 9 and the blower 10 is operated to diffuse the leaked refrigerant.

In the present embodiment, when power is not supplied to the heat pump water heater, such as during a power outage or during transportation, the independent power source 13 different from the power supplied to the heat pump water heater is supplied to the detection means 9 and the blower 10. When the refrigerant is leaked from the protection device 6, the detection means 9 detects the electric power and operates the blower 10 to diffuse the leaked refrigerant.
Thus, the occurrence of combustion with respect to the leaked combustible refrigerant can always be prevented, and a safer product can be obtained.

  In addition, although Embodiment 1-5 demonstrated the case where a refrigerant circuit was applied to the heat pump water heater, this invention is not limited only to this, The freezing apparatus using a combustible refrigerant | coolant, for example, an air conditioner It can also be applied to refrigerators.

It is a circuit block diagram of the heat pump water heater which concerns on Embodiment 1 of this invention. It is an enlarged view of the cover part for fire spread prevention of FIG. It is a circuit block diagram of the heat pump water heater which concerns on Embodiment 2 of this invention. It is a circuit block diagram of the heat pump water heater based on Embodiment 3 of this invention. It is a circuit block diagram of the heat pump water heater based on Embodiment 4 of this invention. It is a circuit block diagram of the heat pump water heater which concerns on Embodiment 5 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Condenser, 3 Expansion valve, 4 Air heat exchanger, 5 Air heat exchanger blower, 6 Protection device, 7 Cover for fire spread prevention, 8 Fire extinguishing device, 9 Detection means, 10 Blower, 11, 12 1st, 2nd flow-path switching valve, 13 Independent power supply

Claims (9)

A compressor that compresses and discharges the refrigerant; a condenser that exchanges heat between the refrigerant discharged from the compressor and water that is a load medium circulating in the hot water supply circuit; and an expansion that decompresses the refrigerant on the downstream side of the condenser A heat pump water heater provided with a refrigerant circuit using a flammable refrigerant as the refrigerant, wherein the valve and an air heat exchanger for evaporating the refrigerant decompressed by the expansion valve are connected in an annular shape;
A protective device that is set to operate at a design pressure of a refrigerant circuit between an outlet of the expansion valve and an inlet of the compressor, and that releases the refrigerant when the refrigerant pressure in the refrigerant circuit becomes equal to or higher than the design pressure. A heat pump water heater characterized by comprising a cover for preventing the spread of fire on the protective device.   The heat pump water heater according to claim 1, wherein a fire extinguishing device for supplying water from a water supply pipe of the heat pump water heater is installed in the vicinity of the protective device.   The heat pump water heater according to claim 1, wherein a detecting means for detecting that the refrigerant has been released and a blower for diffusing the released refrigerant are installed in the vicinity of the protective device.   A flow path switching valve that operates when a discharged refrigerant is detected and closes from the outlet of the compressor to the inlet of the expansion valve in the vicinity of the outlet of the compressor and the inlet of the expansion valve. The heat pump water heater according to claim 3, wherein the heat pump water heater is disposed.   The heat pump water heater according to claim 3 or 4, further comprising an independent power source that supplies power independently to the detection means and the blower that diffuses the refrigerant.   The heat pump water heater according to any one of claims 3 to 5, wherein the detecting means is a sensor that reacts to the released combustible refrigerant.   The heat pump water heater according to any one of claims 3 to 5, wherein the detection means is a temperature sensor that detects a temperature change of a pipe connecting the protection device and the refrigerant circuit.   The heat pump water heater according to any one of claims 3 to 5, wherein the detection means is a flow meter that detects a refrigerant flow rate in a pipe connecting the protection device and the refrigerant circuit.   The heat pump water heater according to any one of claims 1 to 8, wherein a fusible stopper or a rupturable plate is used for the protective device.

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