JP4090179B2 - Heat pump water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat pump hot water supply apparatus that can perform hot water supply using a heat pump cycle.
[0002]
[Prior art]
Conventionally, as a hot water supply apparatus, the structure which heats and utilizes city water using gas, kerosene, and electricity as a heat source is common.
[0003]
In response to such a configuration, a hot water supply device using a heat pump cycle with high operating efficiency has been developed in recent years in order to pump water from the atmosphere and heat water using a refrigerant circuit.
[0004]
FIG. 4 is a configuration diagram of a hot water supply apparatus disclosed in Japanese Patent Publication No. 4-6851, and includes a refrigerant circuit 110 and a hot water storage section 120 as main components.
[0005]
The refrigerant circuit 110 includes a compressor 111 that compresses the refrigerant, a condenser 112 that condenses the compressed refrigerant, an expansion valve 113 that decompresses the condensed refrigerant, an evaporator 114 that expands and evaporates the refrigerant, and the like.
[0006]
The hot water storage unit 120 includes a hot water storage tank 121 that stores use water such as hot water and bath water, and a heat receiver that heats the use water by exchanging heat with refrigerant circulating through the condenser 112. 122, a water supply pump 123 for circulating the water used in the hot water storage tank 121 through the heat receiver 122, and the like.
[0007]
In some cases, hot water higher than the temperature obtained by the refrigerant circuit 110 is required. In such a case, the electric heater 127 is energized for auxiliary heating.
[0008]
With such a configuration, in the refrigerant circuit 110, the refrigerant that has been compressed by the compressor 111 and becomes high temperature and high pressure circulates to the condenser 112, where it is circulated through the heat receiver 122 provided in the hot water heat exchanger 126. Heat exchanges with water to condense.
[0009]
Thereafter, the condensed refrigerant is decompressed by the expansion valve 113 and evaporated by the evaporator 114. The heat required for evaporation at this time is supplied from the atmosphere.
[0010]
On the other hand, when the hot water stored in the hot water storage tank 121 is sent from the bottom side of the hot water storage tank 121 to the upper side of the hot water storage tank 121 through the heat receiver 122 by the water supply pump 123 and passes through the heat receiver 122. Heat is exchanged with the refrigerant and heated to become hot water.
[0011]
The hot water stored in the hot water storage tank 121 in this manner is discharged from the water intake 125 with the pressure of city water pressurized and supplied from the water supply port 124 and used.
[0012]
In winter and the like, frost or ice forms on the evaporator 114 and reduces the efficiency of heat exchange between the outside air and the refrigerant. A defrosting operation is performed in which high-temperature and high-pressure refrigerant from the compressor 111 is circulated in 114 to remove ice and the like that have formed ice.
[0013]
[Problems to be solved by the invention]
However, since the compressor drive frequency immediately after starting the refrigerant circuit is low and gradually approaches a predetermined frequency and becomes a steady state, the temperature of the use water heated by the refrigerant in the condenser is low during this period. When the low usage water is circulated in the hot water storage tank, there is a problem that the usage water already stored at a predetermined temperature is cooled.
[0014]
Of course, in such a case, it is possible to stop the circulation of the used water until the compressor is driven in a steady state, but in such a case, the time until the steady state is reached becomes longer. As a result, there was a problem that the completion of hot water storage was delayed.
[0015]
Therefore, an object of the present invention is to provide a heat pump hot water supply apparatus that has improved convenience so that the compressor can be efficiently put into a steady state and the time to completion of hot water storage can be shortened.
[0016]
[Means for Solving the Problems]
In order to solve the above problems, the invention according to claim 1 is a compressor, a condenser for heating water to be used with a high-temperature and high-pressure refrigerant discharged from the compressor, a decompression device, and an evaporator connected in an annular shape by refrigerant piping. a refrigerant circuit in which a hot water circuit for circulating with the circulation pump to use water in the hot water tank on top of the hot water storage tank through the unloading said condenser from the lower portion of該貯tundish, use water circulating the hot water circuit In the heat pump water heater having a flow rate adjustment valve that adjusts the circulation amount of the refrigerant on the basis of the signal, the refrigerant of the condenser immediately after the refrigerant circuit is started and until the compressor is driven at a steady frequency. The circulation amount is calculated so that the temperature of the use water heated at the predetermined temperature becomes the predetermined temperature, and the circulation is stopped when the temperature of the use water heated by the refrigerant of the condenser is equal to or lower than a preset circulation start temperature. Let It was the time of the circulation starting temperature higher than a pre-set constant circulation temperature below temperatures, characterized by a control means for controlling the flow control valve so as to circulate the predetermined quantity greater amount than the calculated circulation rate And
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a heat pump hot water supply apparatus applied to the description of an embodiment of the present invention, and mainly includes a refrigerant circuit 1, a hot water storage unit 2, and a control unit 3 which is a control means for controlling these movements.
[0022]
The refrigerant circuit 1 includes a compressor 11 that compresses the refrigerant R, a condenser 12 that condenses the refrigerant R, a decompression device 13 that depressurizes or throttles the refrigerant R, and an evaporation that evaporates the refrigerant R by exchanging heat between the refrigerant R and outside air. And so on.
[0023]
In addition, the hot water storage section 2 is a heat storage tank 21 having a heat insulating structure for storing hot water, a heat receiver 22 provided so that the hot water W circulates and is in thermal contact with the condenser, and the hot water W of the hot water tank 21 is received by the heat receiver. 22, a circulation pump 23 circulated through the circulation pump 22, a flow rate adjustment valve 24 that is a flow rate adjustment valve for adjusting the circulation amount of the utilization water circulated by the circulation pump 23, and the temperature of the utilization water returning from the heat receiver 22 to the hot water tank 21. And a discharge temperature detector 25 for detecting the temperature of the water used to enter the heat receiver 22, and an inflow temperature detector 27 for detecting the temperature of the water to be used. An electric heater 47 is appropriately provided on the bottom side of the hot water storage tank. Used when you want to.
[0024]
The condenser 12 and the heat receiver 22 are each formed of a pipe (copper pipe or the like) having excellent heat conduction characteristics, and are in close contact so as to be able to exchange heat, thereby forming a hot water heat exchanger 26. Of course, it is not such a close structure, and various structures such as a double pipe structure formed by inserting the pipe of the condenser 12 into the pipe of the heat receiver 22 may be used.
[0025]
In the refrigerant circuit 1, the refrigerant is compressed by the compressor 11 and is supplied to the condenser 12 at a high temperature and a high pressure. To the heat receiver 22 that is in thermal contact with the condenser 12, the water used in the hot water storage tank 21 is supplied by being pumped by a circulation pump 23 from a circulation supply port 41 provided at the bottom of the hot water storage tank 21. Therefore, the refrigerant circulating in the condenser 12 gives heat to the water used to be supplied to the heat receiver 22, condenses, is depressurized or squeezed by the decompression device, evaporates in the evaporator 14 and returns to the compressor. At this time, the refrigerant evaporates by taking the heat of evaporation from the outside air.
[0026]
On the other hand, the use water heated to about 60 ° C. by receiving heat from the refrigerant in the condenser 12 by the heat receiver 22 returns to the hot water storage tank 21 from the circulation discharge port 42 provided at the upper part of the hot water storage tank 21. Hot water of about 60 ° C. accumulates in order from the top of the tank 21.
[0027]
On the inner wall of the hot water tank, tank temperature detectors 43 to 46 are provided in a predetermined position in the vertical direction, and when these tank temperature detectors 43 to 46 are all at a predetermined temperature or more, the hot water tank 21. The inside is filled with hot water of a predetermined temperature, and it is determined that the hot water storage is completed.
[0028]
When water is injected into the hot water storage tank 21, city water is supplied from a storage water supply port 49 provided at the bottom of the hot water storage tank 21 through a stop cock 51, a pressure reducing valve 52, a check valve 53, and the like. .
[0029]
This stop cock 51 is normally used in an open state, and when the water is used, it is replenished by that amount, so that the hot water tank is always kept full. It is like that.
[0030]
The pressure reducing valve adjusts the water pressure of city water, etc., so that the inside of the hot water tank is always at a constant pressure after depressurization, and the hot water stored in the hot water tank is discharged from the faucet or the like at that pressure. Water can be taken.
[0031]
When the hot water stored in the hot water storage tank is taken in from the water intake 35 such as a shower or a faucet, the water is pumped from the hot water outlet 48 by the internal pressure of the hot water storage tank, and the electric mixing valve 54 uses the city water. After being mixed and adjusted to a set temperature (30 ° C. to 60 ° C.), water is taken.
[0032]
In addition, when the outside air temperature is low as in winter, the hot water W stored in the hot water storage tank 21 may be cooled and may be lower than a desired temperature during hot water supply. Therefore, when the outside air temperature is 15 ° C. or less, for example, the electric heater 47 is driven so that the hot water storage temperature is appropriately increased.
[0033]
By the way, immediately after starting the refrigerant circuit 1, the compressor 11 is not driven at a steady frequency, and the temperature of members such as the condenser 12 does not reach a steady state. For this reason, the temperature of the utilization water W which returns to the hot water storage tank 21 from the condenser 12 may become low under the same hot water storage conditions.
[0034]
Of course, in such a case, it is also possible to stop the use water W from returning to the hot water tank 21 until they reach a certain state.
[0035]
However, since the time until the compressor 11 reaches the steady frequency is faster when the temperature of the condenser 12 is lower, there is an inconvenience that the time becomes longer if the circulation of the water W is stopped.
[0036]
Therefore, in the present invention, the flow rate of the used water W returning to the hot water storage tank 21 is adjusted by a procedure as shown in FIG. 2 so that hot water can be efficiently stored in a short time. The procedure shown in FIG. 2 will be described with reference to the temperature raising process shown in FIG.
[0037]
The temperature rising process shown in FIG. 3 is a qualitative diagram. Curve (1) is when the use water W is circulated from the beginning at a target flow rate described later, and curve (2) is when the use water W is not circulated. Curve (3) shows the temperature raising process when the flow rate is adjusted and circulated according to the present invention. The dotted line indicates the temperature in the steady state.
[0038]
When the control is started, the refrigerant circuit 1 is activated so that the circulation pump 23 is stopped (Q = 0) (step S1).
[0039]
Then, the circulation amount in the steady state is calculated by a method described later, and this is set as the target flow rate Q (step S2), and the temperature T of the used water W returning to the hot water tank 21 is detected by the discharge temperature detector 25 ( Step S3).
[0040]
In this state, since the use water W is not circulating, the temperature rise of the condenser 12 is the fastest, but this does not mean that the compressor 11 or the like reaches the steady state earliest.
[0041]
Although it depends on what state the steady state is set to, if the temperature of the condenser 12 becomes too high, the amount of condensation in the condenser 12 decreases, and the compressor 11 becomes a high load state and is not shown in the figure. The circuit acts to lower the drive frequency of the compressor 11.
[0042]
An arrow A shown in FIG. 3 indicates that the drive frequency is controlled by the protection circuit. In the present invention, the circulation is started before the protection circuit operates.
[0043]
That is, when the temperature T is lower than the circulation start temperature Ts which is the first preset temperature set in advance in step S4 (T ≦ Ts), the circulation stop state is continued and becomes higher than the circulation start temperature Ts. In the case (T> Ts), circulation is started with the flow rate Q set to Q = Qn * α.
[0044]
As described above, the circulation start temperature Ts is a temperature at which the protection circuit does not work. Also, since the temperature of the condenser 12 is lowered by starting circulation, the load on the compressor 11 is reduced and becomes steady earlier. Try to get close to the state. The temperature rising process from point B to point C in FIG. 3 corresponds to this.
[0045]
In this state, when the temperature T reaches the steady circulation temperature Tn that is the second set temperature (step S6), the flow rate Q is set to the target flow rate Qn (step S7).
[0046]
This means that the circulation amount is reduced, so that the heat lost by the condenser 12 per unit time is reduced and the temperature rises, and the compressor 11 acts in the direction of increasing the load. These overall effects quickly bring the system to a steady state.
[0047]
In addition, as an example of each parameter mentioned above, Ts = 40 ° C., Tn = 47 ° C., and α = 1.1 can be exemplified, but these values are the values of the refrigerant circuit 1 such as the compressor 11 and the condenser 12. Needless to say, since it depends on the capacity, the water supply control accuracy of the circulation pump 23, and the like, it cannot be defined unconditionally.
[0048]
Moreover, the target flow rate mentioned above is calculated | required by empirical formula Q = 860 / (WS2-WS1) / 60 [liter / min].
[0049]
Here, WS1 is the temperature of the use water W entering the heat receiver 22 detected by the inflow temperature detector 27, and WS2 is the use water W detected by the discharge temperature detector 25 and exiting from the heat receiver 22. Temperature. And the control part 3 calculates the circulation flow rate Q so that this WS2 may become target temperature which is 3rd setting temperature.
[0050]
However, the inflow temperature WS1 of the use water W may not necessarily coincide with the temperature of the use water W actually flowing in. For example, when the refrigerant circuit 1 is started, the temperature of the portion where the inflow temperature detector 27 such as the hot water heat exchanger 26 and the heat receiver 22 is attached may have increased due to the previous start. It is affected by temperature.
[0051]
Therefore, in the present invention, the temperature of the place where the used water W flowing into the heat receiver 22 is stored, that is, the temperature TS1 of the used water W located in the lower part of the hot water storage tank 21, is used as the inflow temperature.
[0052]
The temperature TS1 is a temperature detected by the in-tank temperature detector 46, and this enables more accurate flow rate control.
[0053]
【The invention's effect】
As described above, according to the present invention, the circulation rate is adjusted so that the temperature of the use water heated by the refrigerant of the condenser and the flow rate adjuster for adjusting the circulation amount of the use water become a predetermined temperature. When the temperature of the use water heated by the condenser refrigerant is equal to or lower than the preset circulation start temperature, the circulation is stopped, and the temperature is equal to or higher than the circulation start temperature and equal to or lower than the preset steady circulation temperature. In some cases, the compressor is more efficient because a controller that controls the flow rate regulator to circulate a predetermined amount more than the calculated circulation amount and further circulate at the calculated circulation amount when the temperature is equal to or higher than the steady circulation temperature. As a result, it becomes possible to improve the convenience by being able to shorten the time until the hot water storage is completed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a heat pump hot water supply apparatus applied to the description of an embodiment of the present invention.
FIG. 2 is a flowchart showing a flow rate adjustment procedure at start-up.
FIG. 3 is a diagram for explaining a temperature raising process of the condenser at the time of startup.
FIG. 4 is a configuration diagram of a hot water supply apparatus applied to a description of a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Refrigerant circuit 2 Hot water storage part 3 Control part 11 Compressor 12 Condenser 13 Depressurization device 14 Evaporator 21 Hot water storage tank 22 Heat receiver 23 Circulation pump 24 Flow rate adjustment valve 25 Temperature detector 25 Discharge temperature detector 27 Inflow temperature detector 43- 46 In-tank temperature detector 47 Electric heater

Claims (1)

A compressor, a condenser that heats water with high-temperature and high-pressure refrigerant discharged from the compressor, a decompression device, and a refrigerant circuit in which an evaporator is connected in an annular shape by refrigerant piping;
A hot water circuit for taking out the use water in the hot water tank from the lower part of the hot water tank and circulating it through the condenser to the upper part of the hot water tank, using a circulation pump ;
A flow rate adjustment valve that adjusts the circulation amount of the use water circulating through the hot water circuit based on a signal;
In a heat pump water heater having
Immediately after starting the refrigerant circuit and until the compressor is driven at a steady frequency, the circulation amount is calculated so that the temperature of the use water heated by the refrigerant in the condenser becomes a predetermined temperature, and When the temperature of the use water heated by the refrigerant of the condenser is equal to or lower than a preset circulation start temperature, the circulation is stopped, and the temperature is equal to or higher than the circulation start temperature and equal to or lower than a preset steady circulation temperature. In some cases , the heat pump hot water supply apparatus has control means for controlling the flow rate adjusting valve so as to circulate a predetermined amount larger than the calculated circulation amount .

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