JP5413594B2 - Heat pump type water heater - Google Patents

Description

  The present invention relates to a two-cycle heat pump hot water supply apparatus in which two different refrigeration circuits are thermally connected by a heat exchanger, and more specifically, heat during single-stage cycle operation at high outside air temperature. The present invention relates to a technique for improving the exchange efficiency.

  In order to generate stable hot water supply even at a low outside temperature, Patent Document 1 proposes a two-cycle heat pump including a low-temperature side refrigeration circuit and a high-temperature side refrigeration circuit. According to this, the compression ratios of the compressors on the low-temperature side and the high-temperature side can be reduced, and the operation can be performed with higher efficiency as compared with a one-way system having a single stage compressor.

  However, in the invention described in Patent Document 1, single-stage cycle operation cannot be performed, and operation in a two-way cycle is unavoidable even at high outside air temperature, so heat exchange efficiency decreases at high outside air temperature. There is a problem.

  Therefore, Patent Document 2 discloses a heat pump type hot water supply device that prevents a decrease in heat exchange efficiency by performing a dual cycle operation at a low outside temperature and a single stage operation at a high outside temperature. Yes.

  However, in the invention described in Patent Document 2, when the operation is switched from the binary cycle to the single-stage cycle, an auxiliary evaporator is required to maintain the evaporation capability of the high-temperature side refrigeration circuit. There is a problem of high costs.

JP-A-4-254156 JP-A-9-119726

  Therefore, an object of the present invention is to provide a two-cycle heat pump hot water supply apparatus in which two different refrigeration circuits are thermally connected by a heat exchanger, without adding components such as an auxiliary evaporator, in particular. The purpose is to improve the heat exchange efficiency during single-stage cycle operation at high outside temperatures.

  In order to solve the above-described problems, the present invention provides a first refrigeration circuit including a first compressor, a first condenser, a first expansion valve, and a first evaporator, a second compressor, a second condenser, A second refrigeration circuit including a two expansion valve and a second evaporator, and a hot water generation circuit that is heated by the first condenser and / or the second condenser to generate hot water having a predetermined temperature, In the heat pump hot water supply apparatus in which the first refrigeration circuit and / or the second refrigeration circuit are operated according to temperature, the first heated portion connected in parallel to the main pipe of the hot water generation circuit and the second Two heated parts, a first heat exchanger in which the first condenser, the second evaporator, and the first heated part are arranged so as to be capable of exchanging heat, and the second heated part is the second heated part. A second heat exchanging part arranged so as to be able to exchange heat with the condenser, and the first heated object First valve means for opening and closing the water flow path, second valve means for opening and closing the water flow path of the second heated portion, and third valve means provided on the refrigerant inflow side and the refrigerant outflow side of the second evaporator And a fourth valve means, a control means for controlling the compressors and the valve means, and the first heat exchange section includes a first inner pipe through which water flows as the first heated section; A second inner pipe through which refrigerant gas discharged from the first compressor flows as the first condenser and the first and second inner pipes inside, and the second expansion as the second evaporator. A multi-tube heat exchanger having an outer pipe for exchanging heat from the valve with the refrigerant in the second inner pipe, and the control means includes the second valve when the outside air temperature is lower than a predetermined temperature. Means, the third valve means and the fourth valve means are opened, the first valve means is closed, and the first and first valve means are closed. Each of the refrigeration circuits is operated to generate hot water by the second heat exchange unit, and when the outside air temperature is a high outside air temperature higher than a predetermined temperature, the first valve means is opened, and the second valve means and the third valve are opened. And the fourth valve means are closed, only the first refrigeration circuit is operated, and hot water is generated by the first heat exchange unit.

  According to a preferred aspect of the present invention, the control means closes the third valve means and opens the fourth valve means to operate the second compressor at the high outside air temperature so that the inside of the outer pipe is substantially Set to vacuum.

  In the present invention, the control means includes a control mode in which the fourth valve means is closed after the second compressor is operated for a predetermined time and the inner pressure of the outer pipe is set in a substantially vacuum state in the outer pipe. And a control mode in which the fourth valve means is closed based on a detection signal of a pressure sensor that detects the above, and any one of them is executed.

  The triple pipe heat exchanger has an inner diameter dimension of the first inner pipe <the second inner pipe <the outer pipe, and the first inner pipe, the second inner pipe, and the outer pipe are respectively A configuration in which piping is made substantially coaxially, and an inner diameter dimension is the second inner pipe <the first inner pipe <the outer pipe, and the outer pipe is piped almost coaxially around the first inner pipe. And a configuration in which a plurality of the second inner pipes are piped along the pipe wall in the first inner pipe or at an arbitrary position in the pipe. Furthermore, in the triple pipe heat exchanger, the second inner pipe is concentrically disposed inside the outer pipe, and the second inner pipe is circumscribed on the inner peripheral surface of the second inner pipe. A configuration in which the polygonal first inner pipe is arranged is also included.

  According to the present invention, particularly when the outside air temperature is a high outside air temperature equal to or higher than a predetermined temperature, the first valve means is opened, the second valve means, the third valve means, and the fourth valve means are closed, and only the first refrigeration circuit is provided. By operating and generating the hot water by the first heat exchange unit, heat exchange between the refrigerant flowing through the first refrigeration circuit and the water flowing through the hot water supply water generation circuit can be performed efficiently. Moreover, since the heat insulation layer is formed in the 1st heat exchange part by making the inside of an outer tube into a substantially vacuum state, heat exchange efficiency is improved further.

The block diagram of the heat pump type hot-water supply apparatus which concerns on one Embodiment of this invention. (A)-(d) Main part sectional drawing and a modification of a 1st heat exchange part. Explanatory drawing for demonstrating the driving | running state at the time of low outside temperature. Explanatory drawing for demonstrating the driving | running state at the time of high outside temperature. Explanatory drawing for demonstrating a evacuation step.

  Next, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. The heat pump hot water supply apparatus 1 supplies hot water to two refrigeration circuits 100 and 200 that are selectively driven at high and low outside temperatures, and hot water supply equipment such as a hot water tank connected to a main pipe. This is a two-cycle heat pump type hot water supply device that includes a hot water supply water generation circuit 300 that performs the above operation.

  One refrigeration circuit 100 (hereinafter referred to as the first refrigeration circuit 100) has a first refrigerant pipe 110 through which a predetermined first refrigerant circulates, and the first refrigerant pipe 110 compresses the first refrigerant. 1 compressor 120 and a first heat exchange unit 130 (first condenser) for exchanging heat between the high-temperature and high-pressure refrigerant generated by the first compressor 120 and water or a second refrigerant of the second refrigeration circuit 200 described later. ), The first expansion valve 140 that expands the first refrigerant from the condensation pressure to the evaporation pressure, and the air-refrigerant heat exchanger 150 (the first one) that exchanges heat between the first refrigerant expanded to the evaporation pressure and the air. 1 evaporator).

  The other refrigeration circuit 200 (hereinafter referred to as the second refrigeration circuit 200) has a second refrigerant pipe 210 through which a predetermined second refrigerant circulates, and the second refrigerant pipe 210 compresses the second refrigerant. The second compressor 220, the second heat exchanger 230 (second condenser) that exchanges heat between the high-temperature and high-pressure refrigerant generated by the second compressor 220 and water, and the second refrigerant is evaporated from the condensed pressure. A second expansion valve 240 that expands to a pressure and a first heat exchange unit 130 (second evaporator) shared with the first refrigeration circuit 100 are provided.

  The second refrigeration circuit 200 further includes a first refrigerant on-off valve 250 (third valve means) on the input side of the first heat exchanging unit 130 and a second refrigerant on-off valve 260 (fourth valve means) on the outlet side. It is provided and the inflow of the second refrigerant into the first heat exchanging unit 130 is restricted. The first refrigerant on-off valve 250 and the second refrigerant on-off valve 260 are, for example, solenoid type on-off valves, and the opening / closing thereof is controlled by control means (not shown).

  In this embodiment, the first and second refrigerants are, for example, hydrofluorocarbons such as HFC-134a and HFC-410A, hydrofluoroolefins such as HFO-1234yf and HFO-1234ze (E), or HFE-245mc. Besides, it is arbitrarily selected according to the specification. The first and second compressors 120 and 220 are arbitrarily selected according to the output and specifications, such as a rotary type and a scroll type.

  The first heat exchanging unit 130 includes an outer pipe 131 through which a second refrigerant is conveyed. Inside the outer pipe 131, a first inner pipe 133 serving as a water flow path and a flow path for the first refrigerant are provided. The second inner tube 132 is provided.

  In this example, as shown in FIG. 2A, the first heat exchanging unit 130 includes a triple layer in which an outer tube 131, a second inner tube 132, and a first inner tube 133 are arranged in a concentric circle. The outer tube 131 and the second inner tube 132, and the second inner tube 132 and the first inner tube 133 are arranged so as to exchange heat with each other.

  The material of the outer tube 131 and the first and second inner tubes 133 and 132 may be arbitrary depending on the specifications, but a copper alloy or an aluminum alloy is preferable in consideration of pressure strength, thermal conductivity, and the like. In particular, the outer tube 131 preferably has pressure resistance so that it does not deform when evacuated as described later.

  Further, in order to increase the mutual heat exchange efficiency between the outer pipe 131 and the first and second inner pipes 133 and 132, fins for increasing the surface area may be provided inside and outside the pipe. Moreover, a heat insulating member may be wound around the outer periphery of the outer tube 131 so that the heat of the outer tube 131 does not leak to the outside air, thereby further improving the heat exchange efficiency.

  In this example, a concentric triple pipe is used for the first heat exchanging section 130, but as an aspect other than this, as shown in FIG. 2B, the first inner pipe is disposed inside the outer pipe 131. 133 may be arranged concentrically, and a plurality of second inner pipes 132 having a small diameter may be arranged along the circumferential direction along the inner wall of the first inner pipe 133.

  According to this, by increasing the diameter of the second inner pipe 132, the surface area of the second inner pipe 132 can be increased, and the heat exchange efficiency can be further increased.

  As another aspect, as shown in FIG. 2 (c), the second inner tube 132 is disposed concentrically inside the outer tube 131, and the second inner tube 132 is disposed on the inner peripheral surface of the second inner tube 132. A square-shaped first inner tube 133 that is inscribed in may be disposed. According to this, the first inner pipe 133 abuts on the inner peripheral surface of the second inner pipe, so that not only the surface area is increased, but also the strength of the pipe is increased. Further, as shown in FIG. 2 (d), even if the first inner tube 133 and the second inner tube 32 are in contact with each other on the side surface, one tube shape is formed and disposed in the outer tube 131. Good.

  Referring to FIG. 1 again, the air-refrigerant heat exchanger 150 is of a fin tube type, and is provided with a fan 151 for forced cooling. The specific configuration and arrangement of the air-refrigerant heat exchanger 150 are optional items in the present invention.

  The second heat exchange unit 230 is a heat exchange unit that exchanges heat between the high-pressure refrigerant (high-temperature refrigerant) in the second refrigerant pipe 210 and a second hot-water supply pipe 320 described later, and has a specific shape. The configuration and arrangement are optional items in the present invention.

  The hot water supply circuit 300 includes a first hot water pipe 310 that exchanges heat with the first heat exchange unit 130 and a second hot water pipe 320 that exchanges heat with the second heat exchange unit 230. These are provided in parallel with the main pipe 301. The first hot water pipe 310 and the second hot water pipe 320 are provided with first valve means and second valve means for selectively switching the flow of water from the main pipe.

  As the first valve means, a first hot water supply opening / closing valve 330 is provided on the inlet side of the first heat exchange section 130 of the first hot water supply pipe 310, and a second hot water supply opening / closing valve 340 is provided on the outlet side. . The 1st hot water supply on-off valve 330 and the 2nd hot water supply on-off valve 340 consist of solenoid type on-off valves, for example, and the opening / closing is controlled by the control means which is not illustrated.

  As the second valve means, the second hot water supply pipe 320 is provided with a third hot water on / off valve 350 on the inlet side of the second heat exchange section and a fourth hot water on / off valve 360 on the outlet side. Similarly, the third hot water supply opening / closing valve 350 and the fourth hot water supply opening / closing valve 360 are, for example, solenoid type opening / closing valves, and the opening / closing thereof is controlled by control means (not shown).

  In this example, the first and second hot water supply pipes 310 and 320 are provided with two hot water supply on / off valves 330 and 340 (350 and 360) on the inlet side and the outlet side. In 300, if the hot water supply opening / closing valve is provided at least on the inlet side, the inflow of water can be selected.

  Next, an example of the operation procedure of the heat pump hot water supply apparatus 1 of the present invention will be described. First, with reference to FIG. 3, the operation procedure at the time of low outside air temperature will be described. At a low outside air temperature, a control unit (not shown) generates hot water in a two-way cycle in which the first refrigeration circuit 100 and the second refrigeration circuit 200 are operated simultaneously. In generating the hot water, the control unit first issues a closing command to the first hot water supply opening / closing valve 330 and the second hot water supply opening / closing valve 340, and in response to this, the first hot water supply opening / closing valve 330 and the second hot water supply opening / closing valve open / close. Valve 340 is closed.

  At the same time, the control unit issues an opening command to third hot water supply opening / closing valve 350 and fourth hot water supply opening / closing valve 360 to open third hot water supply opening / closing valve 350 and fourth hot water supply opening / closing valve 360. As a result, the hot water is sent from the second hot water pipe 320 to the second heat exchange unit 230.

  After preparing to circulate hot water, the control unit operates the first refrigeration circuit 100. In the first refrigeration circuit 100, after the refrigerant is compressed to a predetermined pressure by the first compressor 120, the refrigerant is condensed by exchanging heat with the low-pressure refrigerant of the second refrigeration circuit 200 in the first heat exchange unit 130, It is sent to the first expansion valve 140. The refrigerant is expanded to the evaporation pressure by the first expansion valve 140 and then sent to the air-refrigerant heat exchanger 150 to exchange heat with the atmosphere.

  At the same time, the control unit operates the second refrigeration circuit 200. In the second refrigeration circuit 200, the refrigerant is first expanded to the evaporation pressure in the second expander 240, and then sent into the outer tube 131 of the first heat exchange unit 130, where the adjacent second inner tube 132 is passed through. Heat exchange is performed with the flowing high-pressure refrigerant of the first refrigeration circuit 100.

  Thereby, the low-temperature low-pressure refrigerant in the outer pipe 131 is heated by the high-temperature high-pressure refrigerant flowing through the second inner pipe 132. The low-pressure refrigerant heated by the first heat exchange unit 130 is then compressed to a predetermined pressure by the second compressor 220.

  In the second compressor 220, a high-temperature high-pressure refrigerant is generated and sent to the second heat exchange unit 230. As a result, heat is exchanged between the hot water supply and condensed, and is sent to the second expansion valve 240. Thereby, even when the outside temperature is low, hot water having a stable temperature can be obtained.

  Next, the case where the outside air temperature is relatively high will be described with reference to FIGS. At the time of high outside air temperature, the second refrigeration circuit 200 is basically stopped, and hot water is generated in a cycle using only the first refrigeration circuit 100.

  First, the control unit issues an opening command to the first hot water on / off valve 330 and the second hot water on / off valve 340, and opens the first hot water on / off valve 330 and the second hot water on / off valve 340. At the same time, a closing command is issued to the third hot water supply opening / closing valve 350 and the fourth hot water supply opening / closing valve 360, and the third hot water supply opening / closing valve 350 and the fourth hot water supply opening / closing valve 360 are closed. Accordingly, the hot water is supplied to the first heat exchange unit 130 through the first hot water pipe 310.

  When switching from the dual cycle to the single-stage cycle, the control unit first executes a vacuuming step for evacuating the outer tube 131 with the refrigerant filled in the outer tube 131 of the first heat exchange unit 130. Thus, the refrigerant is collected in a pipe between the first refrigerant on-off valve 250 and the second refrigerant on-off valve 260 including the second compressor 220 and the second heat exchange unit 230.

  When the evacuation step is executed, as shown in FIG. 5, the control unit first issues a closing command to the first refrigerant on / off valve 250 and closes the first refrigerant on / off valve 250.

  In this state, the control unit drives the second compressor 220. Thereby, the refrigerant ahead of the first refrigerant on-off valve 250 is discharged by the second compressor 220 to the discharge side of the second compressor 220. Thereby, the inside of the outer tube 131 is depressurized to a substantially vacuum state.

  Thereafter, the control unit issues a closing command to the second refrigerant on / off valve 260, closes the second refrigerant on / off valve 260, and stops the second compressor 220. According to this, piping between the 1st refrigerant | coolant on-off valve 250 and the 2nd refrigerant | coolant on-off valve 260 including the 1st heat exchange part 130 will be in a vacuum state, and the outer tube | pipe 131 is formed as a heat insulation layer.

  As for the timing of closing the second refrigerant on / off valve 260, a pressure sensor is installed in the vicinity of the outlet side of the first heat exchange unit 130, and the controller detects that the pressure is reduced to a substantially vacuum state. It is preferable to close the second refrigerant on-off valve 260.

  As another method, the first refrigerant on-off valve 250 may be closed and the second refrigerant on-off valve 260 may be closed after a predetermined time has elapsed since the start of driving of the second compressor 220.

  After finishing the evacuation step, the control unit operates the first refrigeration circuit 100. In the first refrigeration circuit 100, the refrigerant is compressed to a predetermined pressure by the first compressor 120, and then condensed by exchanging heat with hot water in the first heat exchanging unit 130. Sent. The refrigerant is expanded to the evaporation pressure by the first expansion valve 140 and then sent to the air-refrigerant heat exchanger 150 to exchange heat with the atmosphere.

  At this time, the first heat exchanging unit 130 functions as a heat insulation layer because the inside of the outermost outer tube 131 that is in contact with the atmosphere is in a substantially vacuum state, so that heat leakage to the outside air is suppressed and the second inner tube 131 is suppressed. Heat exchange between the high-pressure refrigerant flowing through the pipe 132 and hot water flowing through the first inner pipe 133 is efficiently performed.

  The hot water generated by the heat pump hot water supply apparatus 1 of the present invention can be used not only for hot water supply such as a bath but also for various heat source media such as heating, and its use is not particularly limited.

DESCRIPTION OF SYMBOLS 1 Heat pump type hot water supply apparatus 100 1st freezing circuit 110 1st refrigerant | coolant piping 120 1st compressor 130 1st heat exchange part 131 Outer pipe 132 2nd inner pipe 133 1st inner pipe 140 1st expansion valve 150 1st refrigerant | coolant heat exchange Unit 200 Second refrigeration circuit 210 Second refrigerant piping 220 Second compressor 230 Second heat exchange unit 240 Second expansion valve 250 First refrigerant on-off valve 260 Second refrigerant on-off valve 300 Hot water generation circuit 310 First hot water piping 320 Second hot water supply pipe 330 First hot water on / off valve 340 Second hot water on / off valve 350 Third hot water on / off valve 360 Fourth hot water on / off valve

Claims (7)

A first refrigeration circuit including a first compressor, a first condenser, a first expansion valve and a first evaporator; and a second refrigeration circuit including a second compressor, a second condenser, a second expansion valve and a second evaporator. A refrigeration circuit, and a hot water generation circuit that generates hot water at a predetermined temperature by being heated by the first condenser and / or the second condenser, and the first refrigeration circuit and / or according to the outside air temperature. In the heat pump hot water supply apparatus in which the second refrigeration circuit is operated,
The first heated part and the second heated part connected in parallel to the main pipe of the hot water generation circuit, and the first condenser, the second evaporator, and the first heated part exchange heat. A first heat exchanging portion arranged in a possible manner, a second heat exchanging portion in which the second heated portion is arranged to exchange heat with the second condenser, and a water flow path of the first heated portion. The first valve means for opening and closing the second valve means, the second valve means for opening and closing the water flow path of the second heated portion, the third valve means provided on the refrigerant inflow side and the refrigerant outflow side of the second evaporator, and the fourth Valve means; and control means for controlling each compressor and each valve means,
The first heat exchange section includes a first inner pipe through which water flows as the first heated section, and a second inner pipe through which refrigerant gas discharged from the first compressor flows as the first condenser. A multi-tube heat exchange system including the first and second inner pipes and an outer pipe for exchanging the refrigerant from the second expansion valve with the refrigerant in the second inner pipe as the second evaporator. Consisting of a vessel
The control means opens the second valve means, the third valve means and the fourth valve means, closes the first valve means, and closes the first and first valve means when the outside air temperature is a low outside air temperature lower than a predetermined temperature. Each of the second refrigeration circuits is operated to generate hot water by the second heat exchanging unit, and when the outside air temperature is a high outside air temperature equal to or higher than a predetermined temperature, the first valve means is opened, the second valve means, A heat pump type hot water supply apparatus, wherein the three valve means and the fourth valve means are closed, and only the first refrigeration circuit is operated to generate hot water by the first heat exchange unit.   The control means closes the third valve means and opens the fourth valve means at the time of the high outside air temperature to operate the second compressor to bring the inside of the outer pipe into a substantially vacuum state. The heat pump type hot water supply apparatus according to claim 1.   3. The heat pump system according to claim 2, wherein the control means closes the fourth valve means after operating the second compressor for a predetermined time when the inside of the outer pipe is brought to a substantially vacuum state. Hot water supply device.   A pressure sensor for detecting an inner pressure of the outer pipe, and the control means closes the fourth valve means based on a detection signal of the pressure sensor when the inside of the outer pipe is brought into a substantially vacuum state. The heat pump type hot-water supply apparatus according to claim 2.   In the triple pipe heat exchanger, the inner diameter dimension is the first inner pipe <the second inner pipe <the outer pipe, and the first inner pipe, the second inner pipe, and the outer pipe are substantially coaxial. The heat pump type hot water supply apparatus according to any one of claims 1 to 4, wherein the heat pump type hot water supply apparatus is provided with a pipe.   In the triple pipe heat exchanger, the inner diameter dimension is the second inner pipe <the first inner pipe <the outer pipe, and the outer pipe is piped substantially coaxially around the first inner pipe, The heat pump type hot water supply apparatus according to any one of claims 1 to 4, wherein a plurality of the second inner pipes are piped along the pipe wall in the first inner pipe.   In the triple pipe heat exchanger, a polygonal shape in which the second inner pipe is concentrically disposed inside the outer pipe and the second inner pipe is circumscribed on the inner peripheral surface of the second inner pipe. The heat pump type hot water supply apparatus according to any one of claims 1 to 4, wherein the first inner pipe is disposed.

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