JP5221907B2 - Water heater - Google Patents

Description

  The present invention relates to a hot water supply apparatus including a plurality of heat source machines.

It has a heat pump refrigeration cycle that passes the refrigerant discharged from the compressor through a water heat exchanger, a decompressor, and an outdoor heat exchanger and returns it to the compressor. The water heat exchanger functions as a condenser. There is a hot water supply device that circulates water and makes hot water and supplies it to a hot water supply load while storing it in a tank (for example, Patent Document 1).
JP 2005-308250 A

  In the above hot water supply apparatus, it is necessary to always store a sufficient amount of hot water in the tank so as not to hinder the supply of hot water to the hot water supply load.

  The present invention has been made in consideration of the above circumstances, and its purpose is to maintain a water level in the tank at an optimal state at all times, and to provide hot water supply with excellent reliability that does not hinder hot water supply to the hot water supply load. Is to provide a device.

A hot water supply apparatus according to a first aspect of the present invention includes a plurality of heat source units for producing hot water, an open type tank for storing hot water produced by each heat source unit and supplying it to a hot water supply load, and pressure in the open type tank. A pressure sensor to detect, a water level detection means for detecting the water level in the open tank based on the detection pressure of the pressure sensor, and a control means for controlling the number of operating heat source units according to the detected water level of the water level detection means, Provided with an electrode rod detection unit that has a plurality of electrode rods of different lengths along the depth direction of the open tank and detects the water level in the open tank by energizing the liquid between the electrode rods. The control means determines a correction value for the detection water level of the water level detection means when the detection water level of the electrode rod detection unit is full and the detection water level of the water level detection means is not full, and thereafter, the correction value is detected by the water level detection means. Added to the water level And as a new detection level.

  According to the hot water supply apparatus of the present invention, the water level in the tank can always be maintained in an optimum state. Thereby, the hot water supply to the hot water supply load is not hindered, and the reliability can be improved.

[1] A first embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, a plurality of heat source devices 1 are connected in parallel between a water supply side main pipe 2 and a hot water supply side main pipe 3, and the water supply side main pipe 2 and the hot water supply side main pipe 3 are connected to each other. A sealed tank 4 is connected between them. The water supply side main pipe 2 supplies water from a water source (not shown) to the sealed tank 4 and each heat source unit 1 and guides the water (or hot water) in the sealed tank 4 to each heat source unit 1. The hot water supply side main pipe 3 supplies hot water flowing out from each heat source unit 1 to the sealed tank 4 and supplies hot water in the sealed tank 4 to the open tank 5. The open tank 5 is connected to a hot water supply load via a hot water pipe.

  The open tank 5 is provided with an electrode bar detection unit 50 and a pressure sensor 51, which will be described later, as means for detecting the internal water level, and the electrode bar detection unit 50 and the pressure sensor 51 are connected to the control unit 7. .

A specific configuration of each heat source unit 1 is shown in FIG.
That is, the refrigerant discharged from the compressor 11 flows to the water heat exchanger 13 via the four-way valve 12, and the refrigerant that has passed through the water heat exchanger 13 is the expansion valve 14, which is a decompressor, the outdoor heat exchanger 15, and The air is sucked into the compressor 11 through the four-way valve 12. An outdoor fan 16 for supplying outside air to the outdoor heat exchanger 15 is provided in the vicinity of the outdoor heat exchanger 15. The equipment from the compressor 11 to the outdoor fan 16 constitutes a heat pump refrigeration cycle.
A first pipe 21 is connected from the water supply side main pipe 2 to one end of the first flow path of the first three-way valve 22, and the first flow path and the second flow path of the first three-way valve 22 are respectively connected from the other ends. A second pipe 23 is connected to the water inlet of the water heat exchanger 13 via a pump 24. Further, a third pipe 25 is connected to one end of each of the third flow path and the fourth flow path of the second three-way valve 26 from the water outlet of the water heat exchanger 13, and the first three-way is connected to the other end of the third flow path. A fourth pipe 27 is connected to one end of the second flow path of the valve 22. The fifth pipe 28 is connected to the hot water supply main pipe 3 from the middle of the fourth pipe 27, and the sixth pipe 29 is connected to the first pipe 21 from the other end of the fourth flow path of the second three-way valve 26. Is connected. A water cycle is constituted by these parts from the first pipe 21 to the sixth pipe 29.

  The first three-way valve 22 has a first flow path and a second flow path that can be selectively opened and closed, and the second three-way valve 26 is a third flow path and a fourth flow path that can be selectively opened and closed. have.

  A heat exchanger temperature sensor 31 is attached to the water heat exchanger 13, an inflow side temperature sensor 32 is attached in the vicinity of the water inlet of the water heat exchanger 13 in the second pipe 23, and the water heat exchanger 13 in the third pipe 25. An outflow temperature sensor 33 is attached in the vicinity of the water outlet. The heat exchanger temperature sensor 31 detects the temperature (condensation temperature) Tc (° C.) of the water heat exchanger 13. The inflow side temperature sensor 32 detects the temperature Twi (° C.) of water (or hot water) flowing into the water heat exchanger 13. The outflow side temperature sensor 33 detects the temperature Two (° C.) of the hot water (or water) flowing out from the water heat exchanger 13.

  A discharge refrigerant temperature sensor 41 and a high-pressure switch 42 are attached to the high-pressure side refrigerant pipe between the compressor 11 and the four-way valve 12, and a heat exchanger temperature sensor 43 is attached to the outdoor heat exchanger 15. The discharge refrigerant temperature sensor 41 detects the discharge refrigerant temperature Td of the compressor 11. The high pressure switch 42 is activated when the discharge refrigerant pressure (high pressure side pressure) Pd of the compressor 11 is abnormally increased. The heat exchanger temperature sensor 43 detects the temperature (evaporation temperature) Te (° C.) of the outdoor heat exchanger 15.

FIG. 3 shows the appearance of each heat source device 1 of such a hot water supply apparatus, the internal configuration of the open tank 5, the arrangement of the control unit 7, and the like.
First, an electrode bar detection unit 50 is provided on the upper part of the open tank 5. This electrode rod detection unit 50 has a plurality of electrode rods 50a, 50b,... 50e having different lengths along the depth direction of the open-type tank 5, and the electrode rods 50a, 50b,. The water level Sa (%) in the open tank 5 is detected stepwise by energization through the liquid. Among these, the shortest electrode rod 50a is used for detecting full water (100%), and the longest electrode rod 50e is used for detecting drought (0%).

  A pressure sensor 51 and a temperature sensor 52 are attached to the lower part of the open tank 5. The pressure sensor 51 detects the pressure of water in the open tank 5. The temperature sensor 52 detects the temperature of water in the open tank 5.

  Further, an emergency water supply pipe 9 for water supply during drought is communicated with the side wall of the open tank 5, and a two-way valve 53 is provided in the emergency water supply pipe 9.

A control unit 7 is attached to the sealed tank 4, and each heat source unit 1, operation indicator 8, electrode bar detection unit 50, pressure sensor 51, and temperature sensor 52 are connected to the control unit 7 by wiring.
The control unit 7 has the following means (1) to (4) as main functions.
(1) At the start of the operation of the heat source unit 1, the operation of the heat pump refrigeration cycle and the operation of the pump 24 are started, and the detected temperature Tc of the heat exchanger temperature sensor 31 or the detected temperature Twi of the inflow side temperature sensor 32 becomes a set value. Until the second three-way valve 26 is closed and the fourth flow path is opened, and the first three-way valve 22 is opened and the second flow path is closed. An initial circulation circuit in which water circulates through the heat exchanger 13, the third pipe 25, the fourth flow path of the second three-way valve 26, the sixth pipe 29, the first pipe 21, and the first flow path of the first three-way valve 22. 1st control means to form.

  (2) After the initial circuit is formed by the first control means, when the detected temperature Tc of the heat exchanger temperature sensor 31 or the detected temperature Twi of the inflow side temperature sensor 32 exceeds a set value, the first three-way valve 22 By opening one flow path and closing the second flow path, and opening the third flow path of the second three-way valve 26 and closing the fourth flow path, the water in the water supply side main pipe 2 is supplied to the first pipe 21 and the second flow path. The first flow path of the one-way valve 22, the second pipe 23, and the pump 24 are sent to the water heat exchanger 13, and the warm water flowing out of the water heat exchanger 13 is transferred to the third pipe 25 and the third of the second three-way valve 26. Second control means for forming a tapping circuit for sending to the hot water supply side main pipe 3 through the flow path, the fourth pipe 27 and the fifth pipe 28.

  (3) Water level detection means for detecting the water level Sb (%) in the open tank 5 based on the pressure detected by the pressure sensor 51. Unlike the step detection of the electrode rod detection unit 50, this detection is characterized by fine steps without any steps. Hereinafter, the detected water level of the water level detecting means is referred to as a detected water level of the pressure sensor 51.

  (4) Third control means for controlling the operating number N of each heat source unit 1 according to the detected water level Sb (%) of the pressure sensor 51 or the detected water level Sa (%) of the electrode rod detection unit 50.

Next, the operation will be described.
(A) The initial circulation circuit and the hot water circuit of the heat source unit 1
When the operation of the heat source unit 1 is started, the operation of the heat pump refrigeration cycle and the operation of the pump 24 are started until the detected temperature Tc of the heat exchanger temperature sensor 31 reaches the set value Tcs based on the conditions shown in FIG. Until the detection temperature Twi of the inflow side temperature sensor 32 reaches the set value Twis, the third flow path of the second three-way valve 26 is closed and the fourth flow path is opened, and the first flow path of the first three-way valve 22 is opened. Is opened and the second flow path is closed. As a result, as shown by arrows in FIG. 2, in the heat pump refrigeration cycle, the refrigerant discharged from the compressor 11 passes through the four-way valve 12, the water heat exchanger 13, the expansion valve 14, the outdoor heat exchanger 15, and the four-way valve 12. Thus, a flow sucked into the compressor 11 is generated, and the water heat exchanger functions as a condenser. In the water cycle, water flows through the pump 24, the water heat exchanger 13, the third pipe 25, the fourth flow path of the second three-way valve 26, the sixth pipe 29, the first pipe 21, and the first flow of the first three-way valve 22. An initial circulation circuit that circulates through the path is formed.

  After the initial circulation circuit is formed, based on the conditions shown in FIG. 4, when the detected temperature Tc of the heat exchanger temperature sensor 31 exceeds the set value Tcs, or the detected temperature Twi of the inflow side temperature sensor 32 becomes the set value Twis. When exceeded, the first flow path of the first three-way valve 22 is opened and the second flow path is closed, and the third flow path of the second three-way valve 26 is opened and the fourth flow path is closed. As a result, as shown by arrows in FIG. 4, the water in the water supply side main pipe 2 passes through the first pipe 21, the first flow path of the first three-way valve 22, the second pipe 23, and the pump 24, and the water heat exchanger. The hot water flowing out from the water heat exchanger 13 passes through the third pipe 25, the third flow path of the second three-way valve 26, the fourth pipe 27, and the fifth pipe 28 to the hot water supply side main pipe 3. A feeding hot water circuit is formed.

  Thus, at the start of operation, an initial circulation circuit is first formed to warm the water heat exchanger 13, and after the water heat exchanger 13 is sufficiently warmed, the hot water is discharged to the hot water supply side main pipe 3, thereby The unnecessary temperature drop of the hot water flowing through the side main pipe 3 can be avoided, and high-temperature water whose temperature has risen sufficiently is supplied to the sealed tank 4 and the open tank 5 through the hot water supply side main pipe 3.

In particular, since a plurality of heat source units 1 are provided and the number of operating heat source units 1 can be changed, the overall hot water supply capacity can be increased and the hot water supply capacity can be adjusted in a wide range. (B) Stop Of inflow of hot water into the heat source unit 1
In the stopped heat source unit 1, the third flow path of the second three-way valve 26 is closed and the fourth flow path is opened, and the first flow path of the first three-way valve 22 is opened and the second flow path is opened. The hot water supply circuit is closed and the initial circulation circuit of FIG. 2 is prepared. As a result, the hot water in the hot water supply side main pipe 3 made by the operating heat source unit 1 does not flow into the water cycle of the stopped heat source unit 1, and the hot water made by the operating heat source unit 1 and The heat energy can be supplied and stored in the sealed tank 4 and the open tank 5 without waste, and energy saving and reliability can be improved.

(C) Water level detection and operation number control
The water level detection for the open tank 5 and the control of the number of operating heat source units 1 will be described with reference to the flowchart of FIG.
When the pressure sensor 51 is not attached to the open tank 5 (YES in step 101), or when there is some abnormality in the pressure sensor 51 (NO in step 101, YES in step 102), detection by the electrode rod detection unit 50 The operating number N of each heat source unit 1 is controlled according to the water level Sa (%) (step 103). That is, the detection water level Sa (%) of the electrode rod detection unit 50 is compared with the set water level St (%) on the operation indicator 8, and if the detected water level Sa (%) does not reach the set water level St (%). The operating number N of each heat source unit 1 is increased, and if the detected water level Sa (%) exceeds the set water level St (%), the operating number N of each heat source unit 1 is decreased and the detected water level Sa (%) is set. If it is substantially the same as the water level St (%), the operating number N of each heat source unit 1 at that time is maintained. The presence or absence of abnormality of the pressure sensor 51 can be determined from the output of the pressure sensor 51. If there is an abnormality in the pressure sensor 51, information to that effect is displayed on the operation indicator 8.

  When the pressure sensor 51 is attached (NO in step 101), there is no abnormality in the pressure sensor 51 (NO in step 102), and a correction flag f to be described later is not “1” (NO in step 104). Moreover, when the detection water level Sa (%) of the electrode rod detection unit 50 is “full” and the detection water level Sb (%) of the pressure sensor 51 is not “full” (YES in step 106), the number N of operating heat source devices 1 is In addition, the correction value ΔSb (%) for compensating for the error is determined by calculation based on the determination that the error exists in the detected water level Sb (%) of the pressure sensor 51 (step 107) (step 107). 108). With this determination, the correction required flag f is set to “1” (step 109). In this case, since the operating number N of each heat source unit 1 is reduced, it is possible to prevent a problem that hot water overflows from the open tank 5.

  When the correction required flag f is “1” (YES in step 104), the correction value ΔSb (%) is added to the detected water level Sb (%) of the pressure sensor 51 (step 105). Hereinafter, a value obtained by adding the correction value ΔSb (%) is regarded as a new detected water level Sb (%).

  Even when the detection water level Sa (%) of the electrode rod detection unit 50 and the detection water level Sb (%) of the pressure sensor 51 are both “full” (NO in step 106, YES in step 110), the number of operating heat source units 1 N is decreased (step 111).

  When the detection water level Sa (%) of the electrode rod detection unit 50 is “drought” (NO in step 106, NO in step 110, YES in step 112), the number of operating units N of each heat source unit 1 is increased and emergency The two-way valve 53 of the water supply pipe 9 is opened, and urgent water supply to the open tank 5 is performed (step 113). Thereby, the drought of the open type tank 5 can be eliminated immediately.

  When the detection water level Sa (%) of the electrode rod detection unit 50 and the detection water level Sb (%) of the pressure sensor 51 are neither “full” nor “drought” (NO in step 106, NO in step 110, NO in step 112) ), The detected water level Sb (%) of the pressure sensor 51 is corrected according to the detected temperature of the temperature sensor 52 (step 114), and the number N of operating each heat source unit 1 is operated according to the corrected detected water level Sb (%). Is controlled (step 115). Since an error corresponding to the water temperature occurs in the detected water level Sb (%) of the pressure sensor 51, such temperature correction is performed.

  In actual operation number control, the difference ΔS (%) between the detected water level Sb (%) and the set water level St (%) is obtained, and the difference ΔS (%) is compared with the heating capacity setting condition of FIG. .

  For example, when the detected water level Sb (%) is higher than the set water level St (%) and the difference ΔS (%) is in the range of +1 (%) to +5 (%), the heating capacity P = 50 (%) is selected. . When the detected water level Sb (%) is higher than the set water level St (%) and the difference ΔS (%) is in the range of +6 (%) to +10 (%), the heating capacity P = 30 (%) is selected. If the number of heat source devices 1 is 10, the heating capacity P = 50 (%) corresponds to the operating number “5”, and the heating capacity P = 30 (%) corresponds to the operating number “3”. Equivalent to.

  When the detected water level Sb (%) is lower than the set water level St (%) and the difference ΔS (%) is in the range of −1 (%) to −5 (%), the heating capacity P = 70 (%) is selected. . When the detected water level Sb (%) is further lower than the set water level St (%) and the difference ΔS (%) is in the range of −6 (%) to −10 (%), the heating capacity P = 100 (%) is selected. The If the number of heat source devices 1 is 10, the heating capacity P = 70 (%) corresponds to the operating number “7 units”, and the heating capacity P = 100 (%) corresponds to the operating number “10 units”. Equivalent to.

  In the control of the number of operating units, the activation order of the heat source units 1 is sequentially changed and set in the order from the shortest operating time. This is because the operation time of each heat source device 1 is averaged, and as a result, the life of each heat source device 1 is improved.

  As described above, the water level in the open tank 5 is finely detected steplessly by the pressure sensor 51, and the operating number N of each heat source unit 1 is controlled according to the detected water level Sb (%). The water level in 5 can always be maintained in an optimum state. Therefore, the hot water supply from the open tank 5 to the hot water supply load is not hindered, and the reliability can be improved.

  If an abnormality occurs in the pressure sensor 51, the number N of operating heat source devices 1 is controlled according to the detected water level Sa (%) of the electrode rod detection unit 50, which is safe.

  When the detection water level Sa (%) of the electrode rod detection unit 50 or the detection water level Sb (%) of the pressure sensor 51 is full, the number N of operating units of each heat source unit 1 is reduced, so that hot water overflows from the open tank 5. Can be prevented in advance. In particular, if the detection water level Sa (%) of the electrode rod detection unit 50 is full, even if the detection water level Sb (%) of the pressure sensor 51 is not full, the operating number N of each heat source unit 1 is reduced. It is. In addition, in this case, based on the determination that an error exists in the detected water level Sb (%) of the pressure sensor 51, a correction value ΔSb for compensating the error is determined, and thereafter, the correction value ΔSb is used as the detected water level Sb. (%), The reliability of the operation number control according to the detected water level Sb (%) of the pressure sensor 51 is improved.

  When the detection water level Sa (%) of the electrode rod detection unit 50 is drought, the number N of operating heat source devices 1 is increased and the emergency water supply pipe 9 is opened to supply water, so that the drought in the open tank 5 is immediately eliminated. be able to. In this respect as well, there is no hindrance to the hot water supply from the open tank 5 to the hot water supply load, and the safety can be improved as well as the reliability.

  Since the detected water level Sb (%) of the pressure sensor 51 is corrected in accordance with the detected temperature of the temperature sensor 52, the reliability of the operation unit control is greatly improved in this respect as well.

  In controlling the number of operating units, the starting order of the heat source units 1 is sequentially changed and set in the order of short operating time, so that the operating time of each heat source unit 1 is averaged and the life of each heat source unit 1 can be improved.

  In the above embodiment, the case where there is one open type tank 5 has been described as an example. However, as shown in FIG. In this case, one open tank 5 is provided with an electrode rod detection unit 50, a pressure sensor 51, a temperature sensor 52, and a two-way valve 53, and the other open tank 5 is provided with an electrode rod detection unit 50 and a two-way valve. Only 53 is provided. By having a plurality of open-type tanks 5, even when the amount of hot water used for the hot water supply load is large, it is possible to sufficiently cope with the use. Further, even when one open type tank 5 cannot be used for cleaning or the like, it is possible to store hot water in the other open type tank 5 and continue supplying hot water to the hot water supply load.

  In addition, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

The figure which shows the structure of one Embodiment. The figure which shows the specific structure and initial stage circulation circuit of the heat-source equipment in one Embodiment. The figure which shows the external appearance of each heat-source machine in one Embodiment, the structure inside an open type tank, arrangement | positioning of a control unit, etc. FIG. The figure which shows the switching conditions of the initial stage circulation circuit and the tapping circuit in one Embodiment. The figure which shows the tapping circuit of the heat-source machine in one Embodiment. The flowchart for demonstrating the effect | action of one Embodiment. The figure which shows the heating capability setting conditions in one Embodiment. The figure which shows the structure of the modification of one Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heat source machine, 2 ... Water supply side main piping, 3 ... Hot water supply side main piping, 4 ... Sealed tank, 5 ... Open type tank, 7 ... Control unit, 8 ... Operation indicator, 9 ... Emergency water supply pipe, 11 ... Compressor, 13 ... Water heat exchanger, 14 ... Expansion valve (decompressor), 15 ... Outdoor heat exchanger, 51 ... Pressure sensor, 52 ... Temperature sensor, 53 ... Two-way valve

Claims (2)

Multiple heat source machines that make hot water,
An open tank for storing hot water produced by each of the heat source units and supplying it to a hot water supply load;
A pressure sensor for detecting the pressure in the open tank;
Water level detection means for detecting the water level in the open-type tank based on the detection pressure of the pressure sensor;
Control means for controlling the number of operating each heat source unit according to the detected water level of the water level detection means;
An electrode rod detection unit having a plurality of electrode rods having different lengths along the depth direction of the open tank and detecting the water level in the open tank by energizing the liquid between the electrode rods With
The control means determines a correction value for the detection water level of the water level detection means when the detection water level of the electrode rod detection unit is full and the detection water level of the water level detection means is not full, and thereafter, the correction value is set to the water level. The value added to the detection water level of the detection means is the new detection water level.
A water heater characterized by that. The detection unit has a plurality of electrode rods having different lengths along the depth direction of the open tank, and detects the water level in the open tank by energizing the liquid between the electrode rods. Electrode rod detection unit
2. The hot water supply apparatus according to claim 1, wherein the control means reduces the number of operating heat source devices when the detection water level of the electrode rod detection unit is full and the detection water level of the water level detection means is not full. .

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