JP2012026707A - Hot water storage type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water storage type water heater capable of reducing a heat loss of expanded water.SOLUTION: The hot water storage type water heater has a hot water storage operation mode heating water in a hot water storage tank 3 by a heat pump unit 1 to store hot water in the hot water storage tank 3. The hot water storage type water heater includes: a high-temperature discharge path 6 constituted of a high-temperature pipe 4 taking high-temperature hot water or air from an upper part of the hot water storage tank 3, and an on-off valve 5 disposed along the high-temperature pipe 4; a low-temperature discharge path 8 constituted of a low-temperature pipe 7 for taking low-temperature water from a lower part of the hot water storage tank 3; a pressure relief valve 9 disposed to communicate with the high-temperature discharge path 6 and a low-temperature discharge path 8. In the hot water storage operation mode, a time for opening the on-off valve 5 is provided, the expanded water generated in the hot water storage tank 3 is discharged as the low-temperature water to the outside of the hot water storage tank 3 when the on-off valve 5 is closed, and the air in the hot water storage tank 3 can be discharged to the outside when the on-off valve 5 is opened.

Description

  The present invention relates to a hot water storage type hot water heater, and more particularly to an expanded water treatment configuration of a hot water storage type hot water heater.

  As an example of a conventional hot water storage type water heater such as an electric water heater, there is one as shown in FIG. 4 (see, for example, Patent Document 1). FIG. 4 is a configuration diagram of a conventional hot-water storage type water heater described in Patent Document 1.

  In FIG. 4, in the conventional hot water storage type hot water heater, the volume of water increases due to thermal expansion in the process of heating water to warm water by the heating means 107 (hereinafter, increased from the original water volume). The amount of water is called expanded water).

  The hot water storage type hot water heater is connected to the upper part of the hot water storage tank 101, and the hot water in the upper part of the hot water storage tank 101 is discharged by a pressure relief valve 105 which is opened when the pressure in the hot water storage tank 101 exceeds a predetermined value. The expanded water is discharged to the outside of the hot water storage tank 101 to prevent the hot water storage tank 101 from being damaged.

  Further, since the solubility of gas (air) with respect to liquid (water) becomes smaller as the temperature becomes higher, when the water in the hot water storage tank 101 is heated to hot water, the air that cannot be dissolved in the water (hereinafter, this air is referred to as “air”). (Referred to as tank internal air) accumulates in the upper part of the hot water storage tank 101. If a large amount of air remains in the tank, when hot water is used, the hot water and the air in the hot water storage tank 101 are mixed and discharged, so that the hot water scatters from a faucet (not shown), resulting in user discomfort. However, since the air in the hot water storage tank 101 is discharged from the pressure relief valve 105 together with the expanded water, this problem can also be solved (see, for example, Patent Document 1).

  Another example of a conventional hot water storage type hot water heater is as shown in FIG. 5 (see, for example, Patent Document 2). FIG. 5 is a configuration diagram of a conventional hot-water storage type water heater described in Patent Document 2.

  As shown in FIG. 5, the conventional hot water storage type hot water heater includes an air reservoir 202, a first check valve 207, a second check valve 208, a heat exchange unit 203, and a pump 204 provided at the upper part of the hot water storage tank 201. By the provided bypass passage 205 and the pressure relief valve 206 arranged in the middle of the bypass passage 205, a path for discharging the expanded water from the upper part and the lower part of the hot water storage tank 201 through the pressure relief valve 206 is provided. Thus, the expansion water is discharged as low-temperature water through the bypass passage 205 and the pressure relief valve 206 to the outside of the hot water storage tank 201 to reduce heat loss, and the air in the tank is stored in the air reservoir 202, pressure. The hot water is discharged to the outside of the hot water storage tank 201 through the relief valve 206.

Japanese Patent No. 2917796 Japanese Patent No. 4274273

However, when the expansion water is discharged to the outside of the hot water storage tank 101 as in the conventional hot water storage type hot water heater described in Patent Document 1, there is a problem that the heated hot water is thrown away and is wasted.

  For example, when the capacity of the hot water storage tank 101 is 460 L and 5 ° C. water is heated to 90 ° C., simply calculating from the change in the coefficient of thermal expansion of the water, 460 L of water becomes about 478 L of hot water, about 90 ° C., About 18 L of hot water is discharged from the pressure relief valve 105 to the outside of the hot water storage tank 101 without being used.

  Further, in the configuration of another conventional hot water storage type hot water heater as described in Patent Document 2, the heat loss can be reduced because the expansion water is discharged as low temperature water from the bottom of the hot water storage tank 201. If the path is complicated and the first check valve 207 or the second check valve 208 leaks, the expansion water is discharged as hot water, and the heat loss reduction effect is lost. Not only when the hot water and water in the hot water storage tank 201 are mixed by natural convection through the bypass 205, the temperature of the water rises, and when the water in the hot water storage tank 201 is boiled by a heat pump unit (not shown). There was a problem that the operating efficiency was lowered.

  The present invention has been made in view of the above circumstances, and its object is to prevent high-temperature expansion water from being discharged outside the hot water storage tank, and to achieve high efficiency and reliability with low heat loss. It is to provide a high hot water storage type water heater.

  In order to solve the above conventional problems, the hot water storage type water heater of the present invention has a hot water storage operation mode in which the water in the hot water storage tank is heated by the heating means and stored in the hot water storage tank, and the upper part of the hot water storage tank A high-temperature discharge path comprising a high-temperature pipe for taking out hot hot water or air from the high-temperature pipe and an opening / closing means provided in the middle of the high-temperature pipe; a low-temperature discharge path comprising a low-temperature pipe for taking out low-temperature water from the lower part of the hot water storage tank; A pressure relief valve provided so as to communicate with the discharge path and the low temperature discharge path, wherein the opening and closing means is opened for a predetermined time during the hot water storage operation, in the hot water storage operation mode When the opening / closing means is closed, the expansion water generated in the hot water storage tank is discharged as low-temperature water to the outside of the hot water storage tank, and when the opening / closing means is open, the empty space in the tank It can be discharged to the outside of the hot water storage tank.

  According to the present invention, since the expanded water generated in the hot water storage tank is discharged to the outside of the hot water storage tank as low-temperature water, heat loss can be reduced, and a hot water storage type hot water heater with high energy efficiency can be provided.

The block diagram of the hot water storage type hot water heater in Embodiment 1 of this invention Control flow chart of on-off valve of the hot water storage type water heater The block diagram of the hot water storage type water heater in Embodiment 2 of this invention Configuration diagram of a conventional hot water storage water heater Configuration diagram of other conventional hot water storage hot water heaters

1st invention has the hot water storage operation mode which heats the water in a hot water storage tank by a heating means, and stores hot water in the said hot water storage tank, the high temperature piping which takes out hot hot water or air from the upper part of the said hot water storage tank, and the said high temperature A high-temperature discharge path composed of opening / closing means provided in the middle of the piping, a low-temperature discharge path composed of low-temperature piping for extracting low-temperature water from the lower part of the hot water storage tank, and the high-temperature discharge path and the low-temperature discharge path A hot water storage water heater, wherein the open / close means is opened for a predetermined time during the hot water storage operation, and the hot water storage tank when the open / close means is closed in the hot water storage operation mode. The expansion water generated inside is discharged as low-temperature water to the outside of the hot water storage tank, and when the opening / closing means is open, the air in the tank is discharged to the outside of the hot water storage tank. It can be.

  In the second invention, in particular, the high-temperature discharge path and the low-temperature discharge path of the first invention have a merging portion, and the merging portion is disposed above the uppermost portion of the hot water storage tank. Can be reliably discharged outside the hot water storage tank.

  In the third invention, in particular, the heating means of the first or second invention is a heat pump unit, which enables a high-efficiency boiling operation and further improves energy efficiency.

  In particular, the fourth invention uses carbon dioxide as the refrigerant of the heat pump unit according to the third invention. By using carbon dioxide that is relatively inexpensive and stable as the refrigerant, the product cost can be reduced and the reliability can be improved. Can be improved. In addition, carbon dioxide has an ozone depletion coefficient of zero and a global warming coefficient of about 1/700 of the alternative refrigerant HFC-407C, which is very small.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of a hot water storage type hot water heater in the first embodiment of the present invention, and FIG. 2 is a control flowchart of an on-off valve of the hot water storage type hot water heater.

  In FIG. 1, the present embodiment uses a heat pump unit 1 as heating means, and carbon dioxide is enclosed in a refrigerant circuit of the heat pump unit 1. In the hot water storage operation mode, the water at the bottom of the hot water storage tank 3 is conveyed to the heat pump unit 1 by the boiling pump 17, exchanges heat with the refrigerant (carbon dioxide) and is heated to hot water, and then the boiling three-way valve 18 is opened. The hot water is stored in the hot water storage tank 3 by being returned to the upper part of the hot water storage tank 3 via. Reference numeral 2 denotes a hot water storage tank unit for storing the hot water storage tank 3.

  A high-temperature discharge path 6 is constituted by a high-temperature pipe 4 for extracting hot hot water or air from the upper part of the hot water storage tank 3 and an on-off valve 5 as an opening / closing means provided in the middle of the high-temperature pipe 4. Further, a low-temperature discharge path 8 including a low-temperature pipe 7 for extracting low-temperature water from the lower part of the hot water storage tank 3 is configured. The low temperature pipe 7 is connected to the water supply pipe 13 through the pressure reducing valve 14.

  The downstream end of the high temperature discharge path 6 and the downstream end of the low temperature discharge path 8 are connected by a merging portion 11, and an expanded water discharge pipe 10 is communicated with the merging portion 11. A pressure relief valve 9 is provided in the middle of the expansion water discharge pipe 10, and when the pressure in the hot water storage tank 3 becomes a predetermined pressure (for example, 320 kPa) or more, the high temperature discharge path 6 or the low temperature discharge path 8, The expansion water or the tank air is discharged to the outside of the hot water storage tank 3 through the expansion water discharge pipe 10.

  In addition, a check valve 12 as a backflow prevention means is provided in the middle of the low temperature discharge path 8 to prevent water from flowing back from the junction portion 11 toward the bottom of the hot water storage tank 3. Further, the check valve 12 is configured such that even if the check valve 12 is directed from the bottom of the hot water storage tank 3 toward the merging portion 11, water does not flow unless the differential pressure across the check valve 12 exceeds a predetermined differential pressure. . Specifically, in the hot water storage operation mode, when the on-off valve 5 is opened to discharge the air in the tank above the hot water storage tank 3 and the expanded water, the low temperature expanded water is not discharged from the low temperature discharge path 8. As described above, the differential pressure of the check valve 12 is adjusted.

  Note that a part of the low temperature discharge path 8 is shared with a part of the water supply pipe 13 for supplying water to the hot water storage tank 3 so as to reduce the cost by simplifying the pipe structure. In addition to 13, a pipe configuration dedicated to the low temperature discharge path 8 may be used.

  16 is a mixing valve in which the high temperature pipe 4 and the low temperature pipe 7 are connected to the inlet side, and the hot water supply pipe 15 is connected to the outlet side. A hot water supply terminal such as a faucet (not shown) is connected to the terminal of the hot water supply pipe 15.

  The operation and action of the hot water storage type hot water heater of the present embodiment configured as described above will be described below using the flowchart of FIG.

  When the heat pump unit 1 starts the boiling operation and enters the hot water storage operation mode, the process proceeds from Step 1 to Step 2 to open the on-off valve 5 and at Step 3, measurement of the time for which the on-off valve 5 is open is started. Since the water in the hot water storage tank 3 is heated, the volume tends to expand. However, since the volume of the hot water storage tank 3 itself hardly changes, the pressure in the hot water storage tank 3 increases.

  Although the pressure in the hot water storage tank 3 continues to rise as the boiling operation continues, when the pressure exceeds the set pressure of the pressure relief valve 9 (for example, 320 kPa), the tank air accumulated in the upper part of the hot water storage tank 3 and a certain amount of hot water Is discharged to the outside of the hot water storage tank 3 as expanded water through the high temperature discharge path 6, the pressure relief valve 9, and the expanded water discharge pipe 10. A check valve 12 is installed in the middle of the low temperature discharge path 8. The check valve 12 does not flow in the reverse direction (in FIG. 1, the direction of flowing from the upper part to the lower part of the hot water storage tank 3), and a differential pressure of a certain level or more must be applied to the forward flow. If it does not flow. Usually, the differential pressure is adjusted by the spring constant of a spring (not shown) that supports the check valve 12.

  The check valve 12 has a differential pressure adjusted so that the expansion water is not discharged from the low temperature discharge path 8 when the on-off valve 5 is open in the hot water storage operation mode. Further, if the merging portion 11 is disposed above the uppermost portion of the hot water storage tank 3, the air in the tank can be reliably discharged to the outside of the hot water storage tank 3.

  When a predetermined time elapses in Step 4 when the opening / closing valve 5 is opened, the process proceeds to Step 5 and the opening / closing valve 5 is closed. If the boiling operation is continued even after the on-off valve 5 is closed, the expanded water is cooled from the bottom of the hot water storage tank 3 through the low temperature discharge path 8, the check valve 12, the pressure relief valve 9, and the expanded water discharge pipe 10. The water is discharged outside the hot water storage tank 3. At this time, since the expanded water is not discharged as hot water, the heat loss is reduced and the operation efficiency is improved.

  If the hot water storage operation mode is continued while the on-off valve 5 is closed, the air in the tank begins to accumulate in the upper part of the hot water storage tank 3, so that when the on-off valve 5 is closed for a predetermined time, it passes through Step 7 and Step 1. Then, the operation of opening the on-off valve 5 and discharging the air in the tank at Step 2 is repeated.

  In the above series of operations, if a valve leak occurs in the check valve 12 and the on-off valve 5, natural convection occurs in the hot water storage tank 3 via the high temperature discharge path 6 and the low temperature discharge path 8, and the heat pump unit. 1 may cause a reduction in operating efficiency. Although it is difficult to naturally recover the valve leakage of the check valve 12, the on-off valve 5 can be expected to recover from leakage by removing foreign matter while repeating the opening and closing operation several times. Contributes to improved reliability.

In addition, you may change the setting of the time which opens the on-off valve 5, and the time which closes the on-off valve 5 according to boiling temperature and feed water temperature. For example, the amount of air generated in the tank tends to increase when the feed water temperature is low and the boiling temperature is high due to the characteristics of the solubility of air in water. Therefore, when the boiling temperature is high, the time for opening the on-off valve 5 is increased. If the length is set long, the air in the tank can be surely discharged.

(Embodiment 2)
FIG. 3 is a configuration diagram of a hot water storage type hot water supply apparatus according to the second embodiment of the present invention. In FIG. 3, the same parts as those in the first embodiment are given the same reference numerals, and the description thereof is omitted.

  The second embodiment of the present invention differs from the first embodiment in that a check valve as a negative pressure breaking means is provided for the on-off valve 5 installed in the middle of the high temperature discharge path 6. 12 are connected in parallel.

  According to the present embodiment, if for some reason the pressure in the hot water storage tank 3 becomes lower than the pressure outside the hot water storage tank 3, that is, if the internal pressure of the hot water storage tank 3 becomes negative, the hot water storage tank 3 exterior Therefore, air can be quickly introduced into the hot water storage tank 3 through the pressure relief valve 9 and the check valve 12, and the negative pressure destruction of the hot water storage tank 3 can be prevented, thereby improving the reliability. it can.

  In the first and second embodiments, the heat pump unit 1 is used as the heat source. However, the same effect can be obtained by using a combustor or an electric heater as the heat source.

  As described above, the hot water storage type water heater according to the present invention can reduce the heat loss by discharging the expanded water as water from the bottom of the hot water storage tank, and can save energy. Applicable to all related equipment.

1 Heat pump unit (heating means)
2 Hot water storage tank unit 3 Hot water storage tank 4 High temperature piping 5 On-off valve (opening / closing means)
6 High temperature discharge path 7 Low temperature pipe 8 Low temperature discharge path 9 Pressure relief valve 10 Expansion water discharge pipe 11 Junction section 12 Check valve (backflow prevention means)
13 Water Supply Piping 14 Pressure Reducing Valve 15 Hot Water Supply Piping 16 Mixing Valve 17 Boiling Pump 18 Boiling Three-way Valve 19 Check Valve (Negative Pressure Breaking Means)

Claims (4)

There is a hot water storage operation mode in which the water in the hot water storage tank is heated by heating means to store the hot water in the hot water storage tank, and a hot pipe for taking out hot hot water or air from the upper part of the hot water storage tank and an open / close provided in the middle of the high temperature pipe A pressure relief valve provided to communicate with the high-temperature discharge path comprising means, a low-temperature discharge path comprising low-temperature piping for taking out low-temperature water from the lower part of the hot water storage tank, and the high-temperature discharge path and the low-temperature discharge path A hot water storage type hot water supply apparatus, wherein the opening / closing means opens for a predetermined time during the hot water storage operation. The hot water storage type water heater according to claim 1, wherein the high temperature discharge path and the low temperature discharge path have a merging portion, and the merging portion is disposed above an uppermost portion of the hot water storage tank. The hot water storage type hot water supply device according to claim 1 or 2, wherein the heating means is a heat pump unit. The hot water storage type hot water supply device according to claim 3, wherein carbon dioxide is used as a refrigerant of the heat pump unit.