JP2013221718A - Storage type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a storage type water heater that prevents high-temperature expanded water from being discharged out of a hot water storage tank, and has high operation efficiency.SOLUTION: A storage type water heater includes high-temperature piping 4 for taking hot water out of an upper portion of a hot water storage tank 3, low-temperature piping 5 connecting the high-temperature piping 4 to a lower portion of the hot water storage tank 3 or to water supply piping 15 for supplying water to the hot water storage tank 3, a heat exchange circuit which supplies hot water in the hot water storage tank 3 by circulation means 9 in the order of the high-temperature piping 4, a confluence portion 6 between the high-temperature piping 4 and low-temperature piping 5, and a heat exchanger 7 and returns the water into the hot water storage tank 3, an opening/closing means 11 arranged at the low-temperature piping 5, a pressure relief valve 12 communicating with the confluence portion 6, and a control means. In the storage type water heater, a time to put the opening/closing means 11 into an open state is provided in hot water storage operation in which the hot water in the hot water storage tank 3 is heated by a heating means 1.

Description

  The present invention relates to an expanded water treatment configuration in a hot water storage type hot water supply machine.

  Conventionally, in a hot water storage water heater such as an electric water heater as shown in FIG. 4, the volume of water increases due to thermal expansion in the process of heating the water by the heating means 107 into hot water (hereinafter also referred to as “money”). The amount of water increased from the volume of water is called expanded water).

  This type of hot water storage type hot water heater is connected to the upper part of the hot water storage tank 101, and the pressure relief valve 105 is opened when the pressure in the hot water storage tank 101 exceeds a predetermined value. Hot water is discharged as expanded water 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 high temperature hot water, the air that cannot be dissolved in the water (hereinafter, this air is stored in the tank). (Referred to as internal air) accumulates in the upper part of the hot water storage tank 101.

  If a large amount of air is accumulated in the tank, the hot water and the air in the tank are mixed and discharged when the hot water is used. Since the air is discharged from the pressure relief valve 105 together with the expansion water, this problem can also be solved (see, for example, Patent Document 1).

  In addition, as shown in FIG. 5, another hot water storage type water heater of this type includes an air reservoir 202, a first check valve 207, a second check valve 208, and a heat exchange unit 203 provided at the upper part of the hot water storage tank 201. A path for discharging the expanded water from the upper part and the lower part of the hot water storage tank 201 via the pressure relief valve 206 is provided by the bypass path 205 including the pump 204 and the pressure relief valve 206 disposed in the middle of the bypass path 205. ing.

  Accordingly, the expansion water is discharged as low-temperature water to the outside of the hot water storage tank 201 through the bypass passage 205 and the pressure relief valve 206 to reduce heat loss, and the air in the tank is reduced to the air reservoir 202 and the pressure relief. The hot water is discharged from the hot water storage tank 201 through the valve 206 (see, for example, Patent Document 2).

JP 7-217992 A JP 2009-52758 A

  However, when the expansion water is discharged to the outside of the hot water storage tank 101 as in the hot water storage type hot water heater described in Patent Document 1 above, 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 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.

  Further, in the hot water storage type hot water heater (see) described in Patent Document 2, 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, but the piping path is complicated. If the first check valve 207 or the second check valve 208 leaks or the air in the air reservoir 202 disappears, the expansion water is discharged as hot water, reducing heat loss. Not only is the effect lost, but the natural water convection through the bypass 205 mixes the hot water and water in the hot water storage tank 201 to increase the temperature of the water, and the water in the hot water storage tank 201 is removed by a heat pump unit (not shown). There was a problem that the operation efficiency at the time of boiling decreased.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object of the present invention is to provide a hot water storage type hot water heater that prevents high-temperature expanded water from being discharged outside the hot water storage tank and has high operating efficiency.

  In order to solve the above problems, a hot water storage type water heater of the present invention includes a hot water storage tank for storing hot water generated by heating means, a high temperature pipe for taking out hot water from the upper part of the hot water storage tank, the high temperature pipe and the hot water storage tank. A low-temperature pipe connecting a lower part or a water supply pipe for supplying water to the hot water storage tank, and hot water in the hot water storage tank are circulated by means of a circulating means, the junction of the high temperature pipe, the high temperature pipe and the low temperature pipe, a heat exchanger A heat exchanging circuit that flows in sequence and returns to the hot water storage tank; an opening / closing means disposed in the low temperature pipe; a pressure relief valve communicating with the junction; and a control means. In the hot water storage operation for heating the hot water in the tank, a time for opening the opening / closing means is provided.

  Thereby, when the opening / closing means is open, the expanded water generated in the hot water storage tank can be discharged as low temperature water to the outside of the hot water storage tank.

  ADVANTAGE OF THE INVENTION According to this invention, while preventing high temperature expansion water being discharged | emitted out of a hot water storage tank, the hot water storage type hot water heater with high operating efficiency can be provided.

The block diagram of the hot water storage type hot water heater in Embodiment 1 of this invention Operation flow chart of the opening / closing means of the hot water storage type water heater Flowchart of heat recovery operation of hot water storage type water heater in Embodiment 2 of the present invention Configuration diagram of conventional hot water storage type Configuration diagram of other conventional hot water storage hot water heaters

  The first invention includes a hot water storage tank for storing hot water generated by the heating means, a high temperature pipe for taking out hot water from the upper part of the hot water storage tank, a hot water supply pipe for supplying water to the lower part of the hot water storage tank or the hot water storage tank, Heat exchange in which the low temperature pipe connecting the hot water in the hot water storage tank and the hot water in the hot water storage tank are returned to the hot water storage tank by flowing in the order of the high temperature pipe, the junction of the high temperature pipe and the low temperature pipe, and the heat exchanger. A circuit, an opening / closing means disposed in the low-temperature pipe, a pressure relief valve communicating with the merging portion, and a control means, and during the hot water storage operation for heating the hot water in the hot water storage tank by the heating means, A hot water storage type hot water supply machine characterized in that a time for opening the opening / closing means is provided.

  Thus, in the hot water storage operation, when the opening / closing means is open, heat loss can be reduced by discharging the expansion water generated in the hot water storage tank as low-temperature water to the outside of the hot water storage tank.

  The second invention includes a heat source circuit for exchanging heat of the heat source by the heat exchanger, and heat recovery for recovering the heat of the heat source to the hot water in the hot water storage tank with the opening / closing means open. It is characterized by driving.

  Thereby, hot water of a heat source such as a bathtub and water in the hot water storage tank can be heat-exchanged in the hot water storage tank by exchanging heat with the heat exchanger, so that further increase in efficiency can be achieved.

  In the third aspect of the invention, the heating means is a heat pump unit, so that a highly efficient boiling operation can be performed, and the energy efficiency is further improved.

  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 shows a configuration of a hot water storage type hot water supply apparatus according to a first embodiment of the present invention, and a heating means is a heat pump unit 1.

  In FIG. 1, carbon dioxide is enclosed in the refrigerant circuit of the heat pump unit 1.

  During the hot water storage operation, the hot water is stored in the hot water storage tank 3 by a boiling circuit constructed by sequentially connecting the lower part of the hot water storage tank 3, the boiling pump 16, the heat pump unit 1, the three-way valve 17, and the upper or lower part of the hot water storage tank 3 in an annular manner. Stored.

  A high-temperature pipe 4 for extracting hot water from the upper part of the hot water storage tank 3 and a low-temperature pipe 5 for extracting water from a lower water supply tank 3 or a water supply pipe 15 for supplying water to the hot water storage tank are provided at a junction 6.

  Further, the upper part of the hot water storage tank 3, the high-temperature pipe 4, the bath heat exchanger 7 as a heat exchanger, a check valve 8 as a first backflow prevention means, a memorial pump 9 as a first circulation means, the hot water storage tank 3 A heat exchange circuit connected in a ring shape so that hot water from the hot water storage tank 3 flows in sequence, a bath circulation pump 18 as a second circulation means, a bath heat exchanger 7, and a bath 19 as a heat source are sequentially connected in a ring shape. Circuit.

  A check valve 10 serving as a second backflow preventing means is disposed in the middle of the high temperature pipe 4 and upstream of the junction 6, and an opening / closing valve 11 serving as an opening / closing means is provided in the middle of the low temperature pipe 5. Is arranged.

  The check valve 8 prevents water from flowing backward from the hot water storage tank 3 toward the junction 6. Even if the check valve 8 is in the direction from the junction 6 toward the hot water storage tank 3, water does not flow unless the differential pressure across the check valve 8 exceeds a predetermined differential pressure.

  The check valve 10 prevents water from flowing backward from the junction 6 toward the hot water storage tank 3. Further, the check valve 10 is configured such that water does not flow unless the differential pressure across the check valve 10 exceeds a predetermined differential pressure even in the direction from the hot water storage tank 3 toward the junction 6.

Specifically, when the on-off valve 11 is opened in the hot water storage operation, water (actually hot water) does not flow from the upper part of the hot water storage tank 3 toward the junction 6, but the memorial pump 9 is turned on during the chasing operation. When operated, the spring pressure of the check valve 10 is adjusted so that hot water flows through the check valve 10.

  When the on-off valve 11 is opened during the hot water storage operation, the expanded water generated in the hot water storage tank 3 is kept in a low temperature state from the bottom of the hot water storage tank 3 through the low-temperature pipe 5, the on-off valve 11, the junction 6, and the pressure relief valve 12. Discharged.

  On the other hand, when the on-off valve 11 is closed during the hot water storage operation, the expanded water and the internal air generated in the hot water storage tank 3 are in a high temperature state via the high temperature pipe 4, the check valve 10, the junction 6, and the pressure relief valve 12. It is discharged at.

  That is, by opening and closing the on-off valve 11 during the hot water storage operation, it is possible to switch between an operation for discharging low-temperature expanded water to save energy and an operation for discharging the air in the hot water storage tank 3.

  A pressure relief valve 12 is connected to the junction 6, and the expansion water generated during the hot water storage operation is discharged to the outside of the hot water storage tank 3 through the expansion water discharge pipe 13.

  The pressure relief valve 12 is opened when the pressure inside the hot water storage tank 3 becomes a predetermined pressure (for example, 320 kPa) or more, and the expansion water or residual air generated inside the hot water storage tank 3 is stored via the expansion water discharge pipe 13. By being discharged to the outside of the tank 3, the hot water storage tank 3 is prevented from being damaged due to an increase in pressure.

  Further, a negative pressure check valve 21 is connected in the middle of a negative pressure break pipe 20 that communicates the upstream side of the pressure relief valve 12 and the upper part of the hot water storage tank 3.

  If for some reason the pressure inside the hot water tank 3 becomes lower than the pressure outside the hot water tank 3, that is, if the pressure inside the hot water tank 3 becomes negative, the pressure relief valve 12 from the outside of the hot water tank 3 is negative. Air can be quickly introduced into the hot water storage tank 3 through the pressure destruction check valve 21 and the negative pressure destruction pipe 20, and the negative pressure destruction of the hot water storage tank 3 can be prevented, thereby improving the reliability. be able to.

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

  During the hot water storage operation, the control means (not shown) closes the on-off valve 11 at Step 2. It takes several minutes from the start of the hot water storage operation until the outlet water temperature of the heat pump unit 1 (hereinafter referred to as the hot water temperature) reaches the target temperature.

  During this time, the relatively low temperature hot water generated by the heat pump unit 1 is stored in the hot water storage tank 3 via the three-way valve 17 and the lower part of the hot water storage tank 3.

  At this time, 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 hardly changes, the pressure in the hot water storage tank 3 increases.

  As the hot water storage operation continues, the pressure in the hot water storage tank 3 continues to rise. However, if the pressure exceeds the set pressure of the pressure relief valve 12 (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 pipe 4, the pressure relief valve 12 and the expanded water discharge pipe 13.

Thereby, when a user uses hot water, it can prevent that the air and hot water in a hot water storage tank are mixed and scattered, and safety can be improved.

  When the hot water storage operation is further continued and the hot water temperature becomes higher than a predetermined value, the process proceeds from Step 3 to Step 4 and the on-off valve 11 is opened. During this time, the hot water generated by the heat pump unit 1 is stored in the hot water storage tank 3 via the three-way valve 17 and the upper part of the hot water storage tank 3.

  On the other hand, the expanded water generated in the hot water storage tank 3 is discharged from the bottom of the hot water storage tank 3 to the outside of the hot water storage tank 3 through the low temperature pipe 5, the on-off valve 11, the pressure relief valve 12, and the expanded water discharge pipe 13. At this time, since the expanded water is discharged as low-temperature water, the heat loss is reduced and the operation efficiency is improved.

  Here, the on-off valve 11 is switched from the closed state to the open state when the hot water temperature becomes higher than a predetermined value. For example, after the hot water storage operation starts, the open / close valve 11 is closed only for a predetermined time. You may make it switch to an open state.

(Embodiment 2)
FIG. 3 is a flowchart of the operation of the heat recovery operation of the hot water storage type water heater in Embodiment 2 of the present invention.

  In FIG. 3, when there is an instruction to start the heat recovery operation by a remote controller (not shown) operation by the user, the process proceeds from STEP 1 to STEP 2 to switch the on-off valve 11 to the “open” state and the bath circulation pump 18. , The hot water or water in the bathtub 19 is transferred to the bath heat exchanger 7 via the bath circulation pump 18 and then returned to the bathtub 19.

  When the bath circulation pump 18 is operated for a predetermined time (for example, 1 minute), the process proceeds to STEP 3 where the temperature detected by a thermistor (not shown) serving as a bath temperature detecting means is determined as the bath temperature, and the process proceeds to STEP 4.

  Since the bathtub 19 and the hot water storage tank 3 are usually connected by a pipe of several meters (2 to 5 m), the temperature of the bathtub 19 is detected by a thermistor (usually installed near the hot water storage tank 3). Needs to circulate the water in the piping by operating the bath circulation pump 18 for a predetermined time. On the other hand, the temperature in the hot water storage tank 3 is constantly detected by a plurality of thermistors (not shown) installed on the wall surface of the hot water storage tank 3.

  In STEP 4, the remedy pump 9 is operated when the bath temperature is higher than a predetermined temperature (for example, 35 ° C.) and higher than the water temperature at the bottom of the hot water storage tank 3. The hot water transported from the bathtub 19 by the bath circulation pump 18 and the water transported from the lower part of the hot water storage tank 3 by the memory pump 9 exchange heat in the bath heat exchanger 7, so that the hot water is transferred from the bathtub 19 to the hot water storage tank 3. The recovery operation is performed (STEP 6).

  If this heat recovery operation is continued, the bath temperature decreases with time, and when the temperature becomes lower than a predetermined temperature (for example, 20 ° C.), the process proceeds to STEP 7 and the remedy pump 9 and the bath circulation pump 18 are stopped. The heat recovery operation is terminated.

  In STEP 4, when the bath temperature is lower than the water temperature at the lower part of the hot water storage tank 3 or when the bath temperature itself is low (for example, 20 ° C.), it is determined that the heat recovery operation cannot be performed. By stopping the heat recovery operation, unnecessary heat recovery operation is avoided.

  As described above, according to the second embodiment of the present invention, not only can the high efficiency be achieved by discharging the expanded water at a low temperature during the hot water storage operation, but also the heat recovery operation from the hot water in the bathtub 19 to the hot water storage tank 3 can be performed. It becomes possible and can further improve energy saving.

  In the above example, the heat pump unit is used as the heating source. However, the same effect can be obtained even when a combustor or an electric heater is used as the heating source.

As described above, the hot water storage type hot water heater according to the present invention can prevent high temperature expansion water from being discharged outside the hot water storage tank, and can provide a hot water storage type hot water supply apparatus with high operating efficiency. Applicable to all hot water storage hot water heaters that accompany generation.

1 Heating means (heat pump unit)
2 Hot water storage tank unit 3 Hot water storage tank 4 High temperature piping 5 Low temperature piping 6 Junction section 7 Heat exchanger (bath heat exchanger)
8 First backflow prevention means (check valve)
9 First circulation means (remembrance pump)
10 Second backflow prevention means (check valve)
11 Opening / closing means (open / close valve)
12 pressure relief valve 13 expansion water discharge pipe 14 pressure reducing valve 15 water supply pipe 16 boiling pump 17 three-way valve 18 second circulation means (bath circulation pump)
19 Bathtub 20 Negative pressure breaking piping 21 Negative pressure breaking check valve

Claims (3)

A hot water storage tank for storing hot water generated by the heating means, a high temperature pipe for taking out hot water from the upper part of the hot water storage tank, and a low temperature pipe for connecting the high temperature pipe to a lower part of the hot water storage tank or a water supply pipe for supplying water to the hot water storage tank; A heat exchange circuit for returning hot water in the hot water storage tank to the hot water storage tank by circulating the hot water in the order of the high temperature pipe, the joining portion of the high temperature pipe and the low temperature pipe, and a heat exchanger; Open / close means, a pressure relief valve communicating with the merging portion, and a control means, and the heating means opens the open / close means during hot water storage operation for heating hot water in the hot water storage tank. A hot water storage type water heater characterized by having a time to A heat source circuit for exchanging heat of the heat source by the heat exchanger, and performing heat recovery operation for recovering the heat of the heat source in the hot water in the hot water storage tank with the open / close means open. The hot water storage type water heater according to claim 1. The hot water storage type hot water supply apparatus according to claim 1 or 2, wherein the heating means is a heat pump.