JP2006266589A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater capable of considerably reducing a leakage current ratio when starting heat pump operation in hot water supply in the heat pump water heater equipped with a plurality of compressors. <P>SOLUTION: The plurality of compressors are provided, and when hot water discharge is detected to start these compressors, the operation of the compressors is started according to the body temperature of the compressors. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat pump water heater provided with a plurality of compressors.

  Conventionally, regarding a heat pump water heater provided with a plurality of compressors, with respect to a method for starting those compressors, for example, in order to perform peak leveling of an inrush current of a control circuit, the start of one compressor is delayed. There was a thing.

JP 2003-343914 A

  In the prior art, the start-up of a plurality of compressors is delayed, thereby leveling the inrush current to the control circuit and reducing the load on the control circuit.

  However, it has been found that there is a problem of leakage current in addition to leveling the inrush current when starting a heat pump water heater that uses a plurality of compressors. And, when trying to control the start-up of the device so that the leakage current subsides below a certain specified value, the leakage current may not drop to the specified value simply by providing a start-up time difference for leveling the inrush current. understood.

  Also, rather than the so-called hot water storage heat pump water heater that stores hot water in a large-capacity hot water storage tank over a long period of time and uses that hot water for hot water supply, In so-called instantaneous heat pump water heaters that heat to the set temperature and discharge hot water to the outside, the compressor is started and stopped more frequently than the hot water storage heat pump water heater for hot water. The problem of leakage current must be solved.

  Although there is a leakage current cancel circuit as a means for reliably reducing the leakage current, there is a problem of increasing the product cost.

  Accordingly, an object of the present invention is to provide a heat pump water heater capable of greatly reducing a leakage current ratio when a heat pump operation is started during hot water supply in a heat pump water heater provided with a plurality of compressors.

  In order to achieve the above object, the heat pump water heater of the present invention includes a plurality of compressors, and starts operation of the compressor according to the main body temperature of the compressor when detecting the hot water and starting the compressor. . The main body temperature of the compressor may be the temperature of the main body itself or the refrigerant temperature in the compressor. The hot water supply control means for controlling the start of the compressor measures the time from the previous stop of the compressor, estimates the temperature of the compressor body from the measurement result, and compresses based on the estimated body temperature. The activation of the machine may be controlled.

  In order to achieve the above object, the heat pump water heater of the present invention is a heat pump water heater using two compressors. If at least one compressor has a compressor body temperature of a predetermined temperature or more, two heat pump water heaters are used. Start the compressor. If the compressor main body temperature is lower than the predetermined value, the first compressor is started. If the main body temperature of the compressor exceeds the predetermined value, the second compressor is started. By starting the second compressor after the dielectric constant ratio inside the compressor has decreased significantly due to the operation of at least the first compressor, the stray capacity of the device is reduced and leakage current is reduced. It can be below the specified value.

  The hot water supply control means for controlling the start of the compressor measures the time since the previous stop of the compressor, estimates the temperature of the compressor body from the measurement result, and based on the estimated body temperature, When starting is controlled, if the estimated compressor body temperature is equal to or higher than the predetermined temperature, all compressors are started. If the estimated temperature is lower than the predetermined temperature, at least the first compressor is started, and the estimated temperature Based on the above, when the temperature of the first compressor body reaches a predetermined temperature, the second and subsequent compressors may be started.

  When estimating the temperature of a compressor main body, you may make it estimate the temperature according to the refrigerant | coolant and refrigeration oil which are used with a compressor. In that case, from the relationship between the compressor body temperature corresponding to the refrigerant temperature in the compressor and the dielectric constant ratio in the state where the refrigerant and the refrigerating machine oil are present in the compressor, if at least one compressor is equal to or higher than a predetermined temperature, Since the compressor has a reduced dielectric constant, all compressors are activated. Moreover, the start of another compressor can be started in accordance with the temperature of the main body of at least one compressor.

  In order to achieve the above object, the heat pump water heater of the present application further includes an auxiliary tank for storing hot water, and when the compressor cannot be started at the same time, hot water from the tank is replaced with hot water from the water refrigerant heat exchanger of the heat pump circuit. May be mixed and discharged. Thereby, the responsiveness of the hot water becomes faster, and the leakage current ratio can be reduced to a specified value.

  According to the present invention, it is possible to provide a heat pump water heater with a leakage current ratio reduced to a specified value.

  FIG. 1 is a diagram showing an overall configuration of a heat pump water heater to which one embodiment of the present invention is applied. The heat pump device in the present embodiment introduces the supplied water into the water refrigerant heat exchanger 9 as it is, and heat-exchanges the water that has become high temperature in the heat pump circuit described later with the water, thereby adjusting the temperature of the water. The temperature is raised to a temperature at which hot water can be discharged, and the hot water is discharged from a hot water supply terminal (not shown, for example, a faucet, a shower nozzle, and a bathtub) through the hot water supply port 20 as it is. The heat pump water heater in the present embodiment includes a plurality of heat pump circuits in order to obtain a necessary amount of heat. In the present embodiment, the hot water heater having two heat pump circuits will be described, but three or more heat pump circuits may be provided.

  Next, the heat pump circuit will be described. Since the plurality of heat pump circuits have the same configuration, description will be made by adding the suffixes a and b corresponding to the respective heat pump circuits to the reference numerals of the same members.

  The compressors 1a and 1b are provided with compressor surface temperature detection means 2a and 2b that detect the refrigerant temperature of the compressor in a pseudo manner, and are connected to the refrigerant pipe of the water refrigerant heat exchanger 9 through the refrigerant pipe. The refrigerant discharge pressure of the compressors 1a and 1b is detected by the compressor pressure detecting means 7a and 7b provided in the refrigerant pipe.

  The high-temperature refrigerant that has flowed into the refrigerant pipe of the water-refrigerant heat exchanger 9 exchanges heat with water introduced from a water supply pipe that flows through the water pipe of the water-refrigerant heat exchanger 9 described later, and is connected via the refrigerant pipe. The pressure is reduced by the pressure reducing means 6a and 6b. The decompressed refrigerant flows into the evaporators 4a and 4b connected to the decompression means 6a and 6b through the refrigerant pipe and exchanges heat with the outside air. The fans 3a and 3b forcibly supply the outside air to the evaporators 4a and 4b to draw up heat from the outside air. The evaporators 4a and 4b are provided with outside air temperature detecting means 5a and 5b, but these outside air temperature detecting means 5a and 5b may be provided at different positions. The refrigerant from the evaporators 4a and 4b is sucked into the compressors 1a and 1b through the refrigerant pipe.

  On the other hand, the water circuit raises the water supplied from the outside to a set temperature by the water refrigerant heat exchanger 9 and supplies it to an external hot water supply terminal. First, the water flowing in from the water supply port 19 passes through the water pipe provided with the water supply amount detection means 17 and the water supply temperature detection means 16, one is connected to the adjustment water pipe connected to the hot water supply adjustment means 13, and the other is water refrigerant heat. It flows to the water supply pipe connected to the water pipe of the exchanger 9.

  The water supply pipe connected to the water pipe of the water refrigerant heat exchanger 9 branches to a water pipe connected to the auxiliary tank 11 for storing heated water, with a check valve for flowing water in one direction on the way. One of these water pipes is provided with a circulation pump as auxiliary tank circuit circulation means 18.

  In the middle of the hot water supply pipe connected to the hot water supply port 20 connected to the water pipe of the water-refrigerant heat exchanger 9 and supplying hot water having a temperature set to the outside, the hot water is controlled in the hot water control and the auxiliary tank 11 for hot water storage control. Auxiliary tank hot water storage opening / closing means 12 as a switch, hot water supply adjusting means 13 for mixing water supplied to hot water at a set temperature or higher, and a flow rate adjusting valve 15 for adjusting the flow rate of hot water to be discharged are sequentially provided in the flowing water direction. ing.

  The hot water supply pipe detects the temperature when the hot water stored in the auxiliary tank 11 is mixed with the heat exchange water temperature detection means 8 for detecting the temperature of the hot water heated by the water refrigerant heat exchanger 9. A mixing temperature detection means 10 and a hot water supply temperature detection means 14 for detecting the temperature of the hot water to be discharged are provided.

  The hot water supply control means 21 detects the temperature, flow rate, etc. of the entire hot water supply circuit (water cycle, refrigeration cycle) based on the detection results from the respective detection means described above, so that the compressor 1 always discharges a predetermined temperature. The decompression means 6, the fan 3, the auxiliary tank hot water storage opening / closing means 12, the hot water supply adjustment means 13, the flow rate adjustment valve 15 and the like are controlled.

  For the compressor 1, the compressor operation control means 22a and 22b are controlled using a controller for driving the compressors 1a and 1b. For example, when a PAM inverter (rectangular wave drive or sine wave drive) is used, it can be driven with a power factor of 99% and a circuit efficiency of 95% or more.

  Next, the basic operation of this embodiment will be described with reference to FIGS. The horizontal axis in FIG. 2 represents the compressor temperature as a detection result of the compressor surface temperature detection means 2a (2b) for detecting the refrigerant temperature of the compressor 1, and the vertical axis represents the refrigeration oil in the compressor 1a (1b). And the dielectric constant ratio of the refrigerant. As the refrigerant, carbon dioxide (CO2) was used, and as the refrigerating machine oil, for example, PAG oil (polyalkylene glycol oil) was used as the oil having a low volume resistivity.

  In the characteristics of FIG. 2, when the refrigerant temperature detection value of the PAG oil and CO2 refrigerant used in the compressor 1a (1b) reaches, for example, 25 ° C. to 80 ° C., the dielectric constant ratio decreases from 0.98 to 0.93. From this example of characteristics, as the compressor refrigerant temperature reaches a certain temperature, the dielectric constant ratio decreases and the stray capacity of the compressor decreases, resulting in the use of multiple compressors of any specification However, the leakage current is reduced.

  With reference to FIG. 3, control at the time of operation start in a water direct heating hot water supply type heat pump water heater having a plurality of compressors will be described using this characteristic. FIG. 3 shows a flowchart of the compressor starting time difference operation.

First, the refrigerant temperature in the compressors 1a and 1b is detected based on the detection results by the compressor surface temperature detection means 2a and 2b in the figure. (Step S1)
Based on the refrigerant temperature detection result from the hot water supply control means 21, if hot water is detected, start-up control of the compressor 1 is started. (Step S2)
Next, when the compressor refrigerant temperature detection value is obtained (step S3), for example, if the detection value is greater than 0 ° C. (step S4), the compressor operation control means 22 starts the operation of the first compressor 1. To do. (Steps S5 and S6) If the detected value of the compressor refrigerant temperature is larger than 100 ° C., for example (Step S4), all the compressors 1 are started. This is because the refrigerant temperature of the compressor 1 is sufficiently high and the leakage current ratio is sufficiently low. At this time, even if the compressor 1 is started, the water introduced by the water / refrigerant heat exchanger 9 is not sufficiently heated so that hot water from the auxiliary tank 11 is mixed via the auxiliary tank hot water storage opening / closing means 12. The hot water supply control means 21 controls the auxiliary tank hot water storage opening / closing means 12 to do so.

  The hot water supply control means 21 confirms whether or not the first compressor is activated and reaches a temperature at which the main body temperature of the compressor falls below a predetermined dielectric constant ratio. (Step S7) In this embodiment, instead of measuring the actual compressor body temperature, for example, a clock counter using a microcomputer or a dedicated IC is provided in the hot water supply control means 21 and used instead of measuring the temperature.

In the present embodiment, 30 seconds after the start of the first compressor 1 is regarded as the time for the main body temperature of the first compressor to reach a predetermined temperature, and the second compressor 1b A standby state (continues counting until a predetermined time and sets the compressor start command OFF). Then, after 30 seconds have elapsed (when the predetermined time is reached, the compressor start command is turned ON), the compressor operation control means 22 starts the second compressor operation. (Steps S8, S9)
FIG. 4 shows a compressor start time difference table with respect to the surface temperature and temperature of the compressor main body (which may be the refrigerant temperature of the compressor as described above). From the characteristics shown in FIG. 2, the compressor starts from the relationship between the refrigerant constant of the refrigeration oil and refrigerant used in the compressor 1a (1b) with respect to the main body temperature of the compressor 1a (1b) (corresponding to the refrigerant temperature). A time difference table is obtained.

  Using this start-up table, the time elapsed after the compressor 1a (1b) stopped operating for any outside air temperature detection means 5a (5b), for example, a microcomputer or dedicated IC provided in the hot water supply control means 21 Control of predicting (counting up to a predetermined time) the state of the main body temperature of the compressor 1a (1b) may be performed using the clock counter.

  When starting the plurality of compressors 1a (1b), for example, the time after the operation of the compressor 1a and the compressor 1b is stopped is counted by a clock counter, and the compressor refrigerant (surface) temperature is The state is estimated using the table of FIG.

  For example, if the time elapsed since the previous compressor shutdown was short and the main body temperature of the compressor was determined to be 100 ° C or higher, start the first compressor and start the second compressor. . If it is determined that the compressor body temperature has dropped to 10 ° C from the time elapsed since the previous compressor shutdown, when the compressor 1a (1b) is restarted, the first compressor Start 1a. When the main body temperature of the first compressor 1a reaches a predetermined temperature, the second compressor 1b is started. At this time, the second compressor 1b may be started by using a start table in FIG. 4 to start a timer with a start time difference of 30 seconds.

  FIG. 5 shows the characteristics of using the startup time difference table of FIG. 4 and the effect of reducing the actually measured leakage current ratio during simultaneous startup without using the table. In this figure, the horizontal axis indicates the compressor start-up time, and the vertical axis indicates the leakage current ratio between the water heater and the ground. From this figure, comparing the leakage current ratio between when the start control described in this embodiment is used and when it is not used, the leakage current ratio is greatly reduced when the start control of this embodiment is performed. It can be seen that the specified value is also satisfied.

  Further, even if the start control based on the temperature state of the compressor 1a (1b) is performed, the hot water supply control means 21 controls the auxiliary tank hot water storage opening / closing means from the auxiliary tank 11 that keeps the hot water at a predetermined temperature. Since the hot water from the auxiliary tank 11 is mixed with the hot water from the water-refrigerant heat exchanger 9 and the hot water can be discharged from the hot water supply port 20, hot water is supplied in response to the user's request. Can do.

BRIEF DESCRIPTION OF THE DRAWINGS The whole block diagram of the instantaneous type heat pump water heater of this invention. The characteristic figure of the dielectric constant ratio with respect to the compressor refrigerant temperature of this invention. The flowchart figure of the several compressor starting time difference operation of this invention. The compressor starting time difference table with respect to the compressor refrigerant temperature of this invention. The characteristic figure of the leakage current ratio with respect to the compressor starting time of this invention.

Explanation of symbols

1a, 1b ... compressor 1 (compressor 2), 2a, 2b ... compressor refrigerant temperature detection means 1 (compressor refrigerant temperature detection means 2), 3a, 3b ... fan, 4a, 4b ..Evaporator 1 (evaporator 2), 5a, 5b ... Outside air temperature detecting means 1 (outside air temperature detecting means 2), 6a, 6b ... Pressure reducing means 1 (pressure reducing means 2), 7a, 7b Compressor pressure detection means 1 (compressor pressure detection means 2), 8 ... thermal water temperature detection means, 9 ... water refrigerant heat exchanger, 10 ... mixing temperature detection means, 11 ... Auxiliary tank, 12 ... Auxiliary tank hot water storage opening / closing means, 13 ... Hot water supply adjustment means, 14 ... Hot water supply temperature detection means, 15 ... Flow rate adjustment means, 16 ... Water supply temperature detection means, 17 ...・ Water supply amount detection means, 18 ... auxiliary tank circuit circulation means, 19 ... water supply port, 20 ... hot water supply port, 21 ... hot water supply control means, 22a, 22b ... compressor operation control means 1 (Compressor operation control means 2).

Claims (8)

  A heat pump water heater having a plurality of compressors, and having hot water supply control means for starting the compressor according to a main body temperature of the compressor when detecting the hot water and starting the compressor.   2. The heat pump water heater according to claim 1, wherein the hot water control means starts operation of the compressor in accordance with time from the previous stop of the compressor.   2. The heat pump water heater according to claim 1, wherein the hot water supply control unit starts each compressor when detecting the hot water when the main body temperature of at least one of the compressors is higher than a predetermined temperature. 3. Heat pump water heater.   2. The heat pump water heater according to claim 1, wherein when all the compressors are equal to or lower than a predetermined temperature, the hot water supply control means starts the first compressor and the main body temperature of the started compressor is the predetermined temperature. A heat pump water heater that activates another compressor when the temperature is exceeded.   3. The heat pump water heater according to claim 2, wherein the hot water control means starts each compressor when detecting hot water when the time since the previous stop of the compressor is shorter than a predetermined time.   3. The heat pump water heater according to claim 2, wherein when the time since the previous stop of the compressor is longer than a predetermined time, the hot water control means starts the first compressor and A heat pump water heater that activates another compressor when the main body temperature exceeds the predetermined temperature.   2. The heat pump water heater according to claim 1, wherein a water-refrigerant heat exchanger that heats the introduced water by exchanging heat between the high-temperature refrigerant compressed by the compressor and water introduced from a water supply pipe, and hot water And a mixing valve that mixes hot water from the auxiliary tank with hot water heated by the water-refrigerant heat exchanger, and the hot water supply control means uses the mixing valve to start the compressor. A heat pump that mixes hot water from the auxiliary tank with hot water heated by the water-refrigerant heat exchanger, and gradually reduces the amount of hot water supplied from the auxiliary tank according to the time from the start of the compressor. Water heater. A heat pump hot water supply comprising a plurality of compressors, and having a control means for starting the operation of the compressor according to an elapsed time from the end of the previous operation of the compressor when detecting the hot water and starting the compressor Machine.

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