JP2012026693A - Hot water storage type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water storage type water heater with reduced heat loss of expanded water.SOLUTION: The hot water storage type water heater has a hot water storage operation mode heating water by a heat pump unit 1 to store hot water into a hot water storage tank 3. The hot water storage type water heater includes: a mixing valve 5 generating hot water of a predetermined temperature by mixing the hot water of the hot water storage tank 3 with water; a high-temperature discharge path 7 constituted by sequentially connecting a high-temperature pipe 4 discharging high-temperature hot water or air from an upper part of the hot water storage tank 3, high-temperature and low-temperature inlet parts 5a, 5b of the mixing valve 5, and an on-off valve 6; a low-temperature discharge path 9 constituted of a low-temperature pipe 8 for taking low-temperature water from a lower part of the hot water storage tank 3; an expanded water discharge pipe 11 and a pressure relief valve 12 provided to communicate with a joining portion 10 of the high-temperature discharge path 7 and a low-temperature discharge path 9; and a check valve 13 parallely-connected to the on-off valve 6. In the hot water storage operation mode, a time for opening the on-off valve 6 is provided.

Description

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

  As an example of a conventional hot-water storage water heater such as an electric water heater, there is one as shown in FIG. 3 (for example, see Patent Document 1).

  FIG. 3 is a configuration diagram of a conventional hot-water storage type water heater described in Patent Document 1. In FIG. 3, in the conventional hot water storage type hot water heater, the volume of water increases due to thermal expansion in the process of heating the water by the heating means 107 to make warm water (hereinafter, increased from the original water volume). Minute water is referred to as expanded water).

  The conventional hot water storage type hot water heater includes a pressure relief valve 105 which is connected to the upper part of the hot water storage tank 101 and opens when the pressure in the hot water storage tank 101 exceeds a predetermined value. Accordingly, the hot water in the upper part of the hot water storage tank 101 is discharged as expanded water to the outside of the hot water storage tank 101, and the hot water storage tank 101 is prevented 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 tank are mixed and discharged, causing hot water to scatter from the faucet (not shown), resulting in user discomfort. However, since the tank air is discharged from the pressure relief valve 105 together with the expanded water, this problem can be solved.

  Moreover, there exists a thing as shown in FIG. 4 as another example of the conventional hot water storage type water heater (for example, refer patent document 2). FIG. 2 is a configuration diagram of a conventional hot water storage type hot water heater described in Patent Document 2. In FIG.

  As shown in FIG. 4, 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. The provided bypass passage 205 and the pressure relief valve 206 disposed in the middle of the bypass passage 205 are provided, and the pressure relief valve 206 discharges the expansion water from the upper part and the lower part of the hot water storage tank 201 through the pressure relief valve 206. It has a route to do.

  Thus, the expansion water is discharged to the outside of the hot water storage tank 201 as low-temperature water through the bypass passage 205 and the pressure relief valve 206 to reduce heat loss, and the air in the tank is stored in the air reservoir 202 and the 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, in the configuration of the conventional hot water storage type hot water heater as described in Patent Document 1, there is a problem that if the expansion water is discharged to the outside of the hot water storage tank 101, the heated hot water is bothered and wasted. It was.

  For example, when the capacity of the hot water storage tank 101 is 460 L and water at 5 ° C. is heated to 90 ° C., simple calculation from the change in the coefficient of thermal expansion of the water results in 460 L of water becoming 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.

  Moreover, in the conventional hot water storage type water heater as described in the above-mentioned Patent Document 2, since the expansion water is discharged as low-temperature water from the bottom of the hot water storage tank 201, heat loss can be reduced, but the piping path is complicated. When the first check valve 207 or the second check valve 208 leaks, the expansion water is discharged as high-temperature hot water, so that not only the heat loss reduction effect is lost, but also the bypass passage 205. The hot water and water in the hot water storage tank 201 are mixed by natural convection through the water, the temperature of the water rises, and the operation efficiency when boiling the water in the hot water storage tank 201 with a heat pump unit (not shown) is reduced. There was a problem.

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention 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. A mixing valve that mixes water with water to produce hot water of a predetermined temperature, a high-temperature pipe that takes out hot hot water or air from the upper part of the hot water storage tank, a high-temperature inlet portion of the mixing valve, a low-temperature inlet portion of the mixing valve, A high-temperature discharge path configured by sequentially connecting the opening and closing means, a low-temperature discharge path including a low-temperature pipe for extracting low-temperature water from the lower part of the hot water storage tank, and a junction between the high-temperature discharge path and the low-temperature discharge path An expansion water discharge pipe, a pressure relief valve, and a backflow prevention means connected in parallel to the opening / closing means are provided, and the opening / closing means opens for a predetermined time during the hot water storage operation. Before When the opening / closing means is closed in the hot water storage operation mode, 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 air in the tank is stored in hot water. It can be discharged outside the tank.

  ADVANTAGE OF THE INVENTION According to this invention, since the expansion | swelling water which generate | occur | produces in a hot water storage tank is discharged | emitted to the exterior of a hot water storage tank as low temperature water, a 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 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 the hot water in the said hot water storage tank, The hot water of the said hot water storage tank and water are mixed, and hot water of predetermined temperature is produced | generated A high temperature discharge path configured by sequentially communicating a mixing valve, a high temperature pipe for extracting hot hot water or air from an upper part of the hot water storage tank, a high temperature inlet portion of the mixing valve, a low temperature inlet portion of the mixing valve, and an opening / closing means A low temperature discharge path comprising a low temperature pipe for extracting low temperature water from the lower part of the hot water storage tank, and an expansion water discharge pipe provided so as to communicate with a junction between the high temperature discharge path and the low temperature discharge path, and a pressure relief A hot water storage water heater comprising a valve and a backflow prevention means connected in parallel to the opening and closing means, wherein the opening and closing means is opened for a predetermined time during the hot water storage operation. hand When the valve is closed, the expansion water generated in the hot water storage tank is discharged to the outside of the hot water storage tank as low-temperature water, and when the opening / closing means is open, the air in the tank is discharged to the outside of the hot water storage tank. Can do.

  In the second invention, in particular, the junction of the high-temperature discharge path and the low-temperature discharge path of the first invention is arranged above the uppermost part of the hot water storage tank, so that the air in the tank is reliably supplied to the outside of the hot water storage tank. Can be discharged.

  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 of the third invention. The use of carbon dioxide that is relatively inexpensive and stable as the refrigerant reduces the product cost and improves reliability. 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 hot water storage type hot water heater in the present embodiment uses a heat pump unit 1 as a 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.

  The hot water storage type water heater in the present embodiment is a high temperature pipe 4 for extracting hot hot water or air from the upper part of the hot water storage tank 3, a high temperature inlet portion 5a of the mixing valve 5, a low temperature inlet portion 5b of the mixing valve 5, and an opening / closing means. A high-temperature discharge path 7 configured by sequentially connecting the on-off valve 6, a low-temperature discharge path 9 including a low-temperature pipe 8 for extracting low-temperature water from the lower part of the hot water storage tank 3, and the high-temperature discharge path 7 and the low-temperature discharge path 9 An expansion water discharge pipe 11, a pressure relief valve 12, and a check valve 13 as a backflow prevention means connected in parallel to the on-off valve 6 are provided. 2 is a hot water tank unit for storing the hot water storage tank 3, and 15 is a pressure reducing valve provided in the middle of a water supply pipe 14 for supplying water to the hot water storage tank 3.

If for some reason the pressure in the hot water tank 3 becomes lower than the pressure outside the hot water tank 3, that is, if the pressure in the hot water tank 3 becomes negative, the pressure relief valve 12 from the outside of the hot water tank 3 is reversed. Air can be quickly introduced into the hot water storage tank 3 through the stop valve 13, the mixing valve 5, and the high-temperature pipe 4, so that the negative pressure of the hot water storage tank 3 can be prevented and reliability can be improved. Can do.

  The mixing valve 5 generates hot water having a predetermined temperature by mixing hot water flowing from the high temperature inlet portion 5a and low temperature water flowing from the low temperature inlet portion 5b, and connects the hot water supply pipe 16 from the mixing outlet portion 5c. Hot water is supplied from a hot water supply terminal (not shown) such as a faucet, shower or bathtub.

  An expansion water discharge pipe 11 is communicated with the junction 10 between the downstream end of the high temperature discharge path 7 and the downstream end of the low temperature discharge path 9, and a pressure relief valve 12 is provided in the middle of the expansion water discharge pipe 11. When the pressure in the hot water storage tank 3 becomes a predetermined pressure (for example, 320 kPa) or higher, the high temperature discharge path 7 or the low temperature discharge path 9 and the expansion water discharge pipe 11 through the expansion water or the tank Air is discharged outside the hot water storage tank 3.

  In the present embodiment, a part of the low temperature discharge path 9 is shared with a part of the water supply pipe 14 for supplying water to the hot water storage tank 3 so as to reduce the cost by simplifying the pipe structure. However, a pipe configuration dedicated to the low temperature discharge path 9 may be used separately from the water supply pipe 14.

  The operation and action of the hot water storage type water heater in the present embodiment configured as described above will be described with reference to the flowchart of FIG.

  When the heat pump unit 1 starts the boiling operation and enters the hot water storage operation mode, the process shifts from Step 1 to Step 2 to open the on-off valve 6 and at Step 3, the time for opening the on-off valve 6 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. As the boiling operation continues, the pressure in the hot water storage tank 3 continues to rise. However, when the pressure exceeds the set pressure of the pressure relief valve 12 (for example, 320 kPa), the tank internal air accumulated in the upper part of the hot water storage tank 3 and a slight amount Hot water is discharged outside the hot water storage tank 3 as expanded water through the high temperature discharge path 7, the pressure relief valve 12, and the expanded water discharge pipe 11.

  Further, if the junction 10 is disposed above the uppermost part 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 the time during which the on-off valve 6 is opened in Step 4 has passed a predetermined time, the process proceeds to Step 5 and the on-off valve 6 is closed. If the boiling operation is continued even after the on-off valve 6 is closed, the expanded water is stored in the hot water storage tank 3 as low temperature water from the bottom of the hot water storage tank 3 through the low temperature discharge path 9, the pressure relief valve 12, and the expanded water discharge pipe 11. Is discharged outside. 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 6 is closed, the air in the tank begins to accumulate in the upper part of the hot water storage tank 3, so that when a predetermined time elapses, the process goes through Step 7 and Step 1. In Step 2, the operation of opening the on-off valve 6 again and discharging the air in the tank is repeated.

  In addition, you may change the setting of the time which opens the on-off valve 6, and the time which closes the on-off valve 6 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, the opening time of the on-off valve 6 is high when the boiling temperature is high. If the length is set long, the air in the tank can be surely discharged.

  In addition, although the said embodiment demonstrated using the heat pump unit 1 as a heat source, the same effect can be acquired even if it uses a combustor and an electric heater as a 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 Mixing valve 5a High temperature inlet 5b Low temperature inlet 5c Mixing outlet 6 Opening / closing valve (opening / closing means)
7 High-temperature discharge path 8 Low-temperature pipe 9 Low-temperature discharge path 10 Merge section 11 Expansion water discharge pipe 12 Pressure relief valve 13 Check valve (backflow prevention means)
14 Water Supply Piping 15 Pressure Reducing Valve 16 Hot Water Supply Piping 17 Boiling Pump 18 Boiling Three-way Valve

Claims (4)

A hot water storage operation mode in which the water in the hot water storage tank is heated by the heating means to store the hot water in the hot water storage tank, and the mixing valve for generating hot water at a predetermined temperature by mixing the hot water in the hot water storage tank with water; A hot pipe for taking hot hot water or air from the upper part of the hot water storage tank, a high temperature inlet part of the mixing valve, a low temperature inlet part of the mixing valve, and a high temperature discharge path constituted by sequentially connecting the opening and closing means; A low-temperature discharge path comprising a low-temperature pipe for taking out low-temperature water from the lower part; an expansion water discharge pipe, a pressure relief valve provided so as to communicate with a junction between the high-temperature discharge path and the low-temperature discharge path; and the opening / closing means And a backflow prevention means connected in parallel to each other, wherein the open / close means opens for a predetermined time during the hot water storage operation. The hot water storage type hot water supply apparatus according to claim 1, wherein a joining portion of the high temperature discharge path and the low temperature discharge path is disposed above the uppermost part 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.