JP5938573B2 - Water heater - Google Patents

Description

  The present invention relates to a hot water supply apparatus that supplies hot water using hot water stored in a hot water storage tank.

  Conventionally, as this type of hot water supply apparatus, there is one that performs hot water supply using high-temperature hot water stored in a hot water tank (see, for example, Patent Document 1).

  FIG. 6 shows a conventional hot water supply apparatus described as the first embodiment of the publication. As shown in the figure, this hot water supply apparatus includes a heat pump unit 2 having a gas cooler (hot water supply heat exchanger) 1 and a hot water storage unit 4 having a hot water storage tank 3 in which hot water boiled by the gas cooler 1 is stored. It is configured. The refrigerant circulation path of the heat pump unit 2 includes a compressor 5, a gas cooler 1, an expansion valve (decompression device) 6, an evaporator 7, and the like. The water circuit of the hot water storage unit 4 includes the circulation pump 8, the gas cooler 1, and hot water storage. It is comprised from the tank 3 grade | etc.,.

  The high-temperature and high-pressure gas refrigerant compressed by the compressor 5 is heat-exchanged with the water stored in the hot water storage tank 3 in the gas cooler 1 to heat and boil the water. And it is set as the structure provided with the adder (scale suppression means) 9 which supplies the additive which suppresses the production | generation of a scale in the water circulation path from the hot water tank 3 to the gas cooler 1. FIG.

  Further, the conventional hot water supply device (not shown) described as the second embodiment of the above publication is provided with a bypass circuit (not shown) that bypasses the adder 9, and a three-way valve is provided at a branch point of the bypass circuit. (Not shown).

JP 2011-69572 A

  However, the configuration of the conventional first embodiment has the following problems because the adder 9 is provided in series in the water circulation path from the hot water tank 3 to the gas cooler 1. That is, since the concentration of the additive contained in the water sent from the hot water tank 3 to the gas cooler 1 by the circulation pump 8 varies greatly depending on the flow rate of the water sent to the gas cooler 1, and affects the suppression effect of scale generation. Necessary effects cannot be obtained, and additives may be excessively wasted.

  FIG. 7 shows changes in the city water temperature, the boiling flow rate, and the additive concentration with respect to the outside air temperature, with the outside air temperature on the horizontal axis and the city water temperature, the boiling flow rate, and the additive concentration on the vertical axis. is there. In general, the heating capacity of a hot water supply device is substantially constant even when the outside air temperature changes. On the other hand, when the outside air temperature changes, the city water temperature, which is the temperature of the tap water at that time, also changes (in general, the higher the outside air temperature, the higher the city water temperature). If the temperature stored in the hot water tank 3 (the temperature heated by the gas cooler 1) is the same, the higher the outside air temperature, the higher the city water temperature and the higher the boiling flow rate. Accordingly, the additive concentration decreases accordingly. Become.

  Now, when it is designed to have the necessary concentration of additives that have the effect of suppressing scale generation under winter conditions with low outside air temperature (for example, outside air temperature 7 ° C), the effect of suppressing scale generation is small in the intermediate period and summer. Thus, there is a problem that the scale adheres to the gas cooler 1 and grows. On the contrary, when it is designed at the required concentration of the additive that exhibits the effect of suppressing the scale formation under the summer conditions where the outdoor temperature is high (for example, the outdoor temperature of midnight at 25 ° C.), the additive more than necessary is dissolved in winter. In other words, there is a problem that the life of the additive is shortened, maintenance such as replacement and replenishment is increased, and maintenance cost is increased.

FIG. 7 shows a case where the outside air temperature has changed, such as a seasonal change, but there are the following problems even if the outside air temperature is the same. FIG. 8 shows the boiling time for storing hot water in the hot water tank 3 on the horizontal axis, the incoming temperature supplied to the gas cooler 1 on the vertical axis, the boiling flow rate that is the flow rate of water flowing through the gas cooler 1, and The additive concentration is taken, and the changes in the incoming water temperature, the boiling flow rate, and the additive concentration with respect to the boiling time are shown.

  For example, when the entire hot water tank 3 is boiled from the state where the entire hot water tank 3 is filled with water at 9 ° C., the water at the lower part of the hot water tank 3 is sent to the gas cooler 1 by the circulation pump 8 and the required temperature (for example, After the temperature of the water is raised to 85 ° C., the hot water is stored from the upper part of the hot water tank 3 by being sent to the upper part of the hot water tank 3.

  At this time, inside the hot water tank 3, there is a hot water layer of 85 ° C. at the top and a water layer of 9 ° C. at the bottom. Between these two layers is a mixed layer that varies from 85 ° C to 9 ° C. When the whole amount of the hot water storage tank 3 is boiled, finally, the mixed layer portion is boiled (the mixed layer portion shown in the figure). At this time, since the incoming water temperature which is the temperature of the water sent to the gas cooler 1 rises, the boiling flow rate increases and the additive concentration decreases. As described above, even when the outside air temperature is the same, the incoming water temperature changes, and as a result, the additive concentration changes, and the same problem as described in FIG. 7 occurs.

  In the configuration of the conventional second embodiment, since the bypass circuit and the circuit with the adder 9 are switched, the case where the circuit with the adder 9 is used has been described with reference to FIGS. Therefore, the same problem as described above occurs.

  In addition, a scale inhibitor such as polyphosphate has a great effect of preventing adhesion and deposition on the gas cooler 1 and the like in order to prevent the growth of calcium carbonate crystals when calcium carbonate is scaled.

  However, once deposited and in a hard scale state, there is little work to refine the crystal structure, so the configuration of the conventional second embodiment is the same as the configuration of the conventional first embodiment. Since the effect of suppressing the scale generation is less than when the additive is continuously dissolved during the boiling operation, the heat exchanger such as the gas cooler 1 may be clogged while the scale inhibitor is consumed. There is also. In order to prevent this, it is necessary to add more scale inhibitor than necessary.

  This invention solves the said subject, and it aims at providing the hot-water supply apparatus aiming at the lifetime of a scale inhibitor extending and reducing maintenance and maintenance costs, such as the replacement | exchange and replenishment.

In order to solve the above-mentioned conventional problems, a hot water supply apparatus of the present invention is a hot water supply in which hot water is stored in a hot water storage tank, a high-temperature refrigerant produced by heating means, and water sent from the lower part of the hot water storage tank. comprising a heat exchanger, a water inlet conduit which connects the lower portion of the hot water storage tank and the hot water supply heat exchanger, and a hot water pipe connecting the upper portion of the hot water storage tank and the hot water supply heat exchanger, entering-water pipe A scale suppression means for adding a scale inhibitor that suppresses the generation of scale provided in parallel to the path; and a flow rate of water that is sent from the lower part of the hot water tank and heated to a predetermined temperature in the hot water heat exchanger. Even if there is a change, the ratio of the branch flow rate of water flowing through the scale suppression means to the flow rate of water heated to the predetermined temperature by the hot water supply heat exchanger, and heating to the predetermined temperature by the hot water supply heat exchanger Concentration of the scale inhibitor in water And it is characterized by being configured to be substantially constant.

  As a result, the concentration of the scale inhibitor becomes almost constant even when the incoming water temperature changes, and the scale formation can be effectively suppressed, thereby extending the life of the scale inhibitor and maintaining and maintaining costs such as replacement and replenishment. The hot water supply apparatus which can reduce is provided.

  In the hot water supply apparatus of the present invention, the scale suppression means for adding the scale inhibitor is provided in parallel with the water inlet pipe, thereby reducing the replacement frequency of the scale inhibitor and extending the life. Furthermore, in the short term, the concentration of the scale inhibitor can be made substantially constant even when the mixed layer of the hot water tank is boiled and the incoming water temperature changes greatly.

Configuration diagram of hot water supply apparatus in Embodiment 1 of the present invention The characteristic figure which shows the change of the characteristic to the flow rate of the hot water supply device (A) Explanatory drawing explaining the circuit structure of the water intake line of the scale suppression means of the same hot water supply apparatus, (b) Explanatory drawing explaining the circuit structure of another water intake pipe line of the scale suppression means of the same hot water supply apparatus. The block diagram of the hot-water supply apparatus in the reference example 1 of this invention The block diagram of the hot-water supply apparatus in the reference example 2 of this invention Configuration diagram of conventional hot water supply equipment The characteristic figure which shows the change of the characteristic with respect to the outside temperature of the hot water supply device The characteristic figure which shows the change of the characteristic with respect to the boiling time of the hot water supply device

1st invention consists of the hot water storage tank which stores hot water, the high temperature refrigerant | coolant produced with the heating means, the hot water supply heat exchanger with which the water sent from the said hot water storage tank lower part is heat-exchanged, and the said hot water supply heat exchanger, A water inlet line connecting the lower part of the hot water tank and a hot water outlet line connecting the hot water heat exchanger and the upper part of the hot water tank, and generating a scale provided in parallel with the water inlet line Even if the flow rate of water sent from the lower part of the hot water storage tank and heated to a predetermined temperature in the hot water supply heat exchanger changes, the hot water supply heat exchanger has The ratio of the branch flow rate of water flowing through the scale suppression means to the flow rate of water heated to the predetermined temperature, and the dissolution concentration of the scale inhibitor of water heated to the predetermined temperature in the hot water heat exchanger that is, it configured to be substantially constant A hot water supply apparatus according to symptoms.

As a result , the concentration of the scale inhibitor becomes substantially constant even when the incoming water temperature changes.

For this reason , since scale generation can be effectively suppressed, the life of the scale inhibitor is extended, and maintenance and maintenance costs such as replacement and replenishment can be reduced .

In the second invention, the scale inhibitor uses a polyphosphate .

As a result , when calcium carbonate is scaled, growth of calcium carbonate crystals is prevented, so that the effect of preventing the scale from adhering and depositing inside a heat exchanger such as a gas cooler is great.

For this reason, while improving the durability of an apparatus, the lifetime of heat exchangers, such as a gas cooler, becomes long, and maintenance and maintenance costs, such as the replacement | exchange and replenishment, can be reduced.

In the third invention, a heat pump unit is used as the heating means .

Thereby , energy saving can be aimed at.

(Embodiment 1)
FIG. 1 is a configuration diagram of a hot water supply apparatus according to the first embodiment of the present invention. In FIG. 1, the heating means that is a heat source of the hot water supply apparatus is a heat pump unit 55 that constitutes a heat pump cycle including a compressor 51, a hot water supply heat exchanger 52, a decompression apparatus 53, and an evaporator 54 that absorbs atmospheric heat.

  Then, carbon dioxide whose refrigerant pressure on the high pressure side is equal to or higher than the critical pressure is used as the refrigerant. Water is supplied to the hot water storage tank 57 stored in the hot water storage unit 56 through a water supply pipe 58 connected to the lower part of the hot water storage tank 57, and hot water in the upper part of the hot water storage tank 57 passes through the hot water supply pipe 59 and is supplied by the hot water mixing valve 60. Hot water is supplied from the hot water supply terminal (faucet 62) through the hot water supply pipe 61 after being hot water having a predetermined temperature by mixing with the hot water supply.

  Further, a boiling circuit is constructed by sequentially connecting the circulation pump 63, the water inlet pipe 64, the hot water supply heat exchanger 52, the hot water outlet pipe 65 and the upper part of the hot water tank 57 from the lower part of the hot water tank 57. The water sent by the circulation pump 63 is heated by the refrigerant heat in the hot water supply heat exchanger 52 and stored from above the hot water storage tank 57.

  The hot water temperature heated by the heat pump heat source is detected by the boiling temperature detection means 66 provided in the hot water outlet pipe 65 connected to the water side outlet of the hot water supply heat exchanger 52. Furthermore, a scale suppression means 68 filled with a scale inhibitor 67 is connected in parallel to the water inlet pipe 64.

  About the hot water supply apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. In FIG. 1, a hot water supply heating operation for boiling the hot water storage tank 57 will be described. If there is a request (not shown) for boiling the hot water storage tank 57, the heat pump unit 55 performs a hot water supply heating operation using atmospheric heat. In this case, high-temperature and high-pressure refrigerant discharged from the compressor 51 flows into the hot water supply heat exchanger 52 where heat is exchanged with the water sent from the lower part of the hot water tank 57 to dissipate heat, and then the pressure is reduced. The pressure is reduced by the device 53, and heat is absorbed from the atmosphere by the evaporator 54, gasified, and returned to the compressor 51.

  At this time, the water sent from the lower part of the hot water storage tank 57 flowing into the hot water supply heat exchanger 52 through the water inlet pipe 64 is a circulation pump so that the temperature at the outlet of the hot water supply heat exchanger 52 becomes a predetermined temperature. By controlling the number of revolutions 63, hot water of a predetermined temperature flows from the upper part of the hot water tank 57 and is stored.

  At this time, since the scale suppression means 68 filled with the scale inhibitor 67 is connected in parallel to the water inlet pipe 64, a part of the water sent from the lower part of the hot water tank 57 by the circulation pump 63 is a branch point. A flows through the circuit including the scale suppression means 68. And the water which flowed into the scale suppression means 68 and dissolved the scale inhibitor 67 is mixed with the water which did not circulate through the scale suppression means 68 side at the junction B.

  Then, it flows into the hot water supply heat exchanger 52 and is heated to a predetermined temperature as described above. At this time, the scale inhibitor contained in the water suppresses the growth of calcium carbonate crystals generated in the hot water heat exchanger 52 and prevents the generation of scale.

  FIG. 2 shows the ratio of the branch flow rate flowing through the circuit (point A → point C → point B) having the scale suppression means 68 for the boiling flow rate on the horizontal axis and the scale suppression agent on the vertical axis. The ratio of the branch flow rate to the change in the boiling flow rate and the change in the concentration of the scale inhibitor are shown. As can be seen from the figure, even if the boiling flow rate changes, the ratio of the branch flow rate and the concentration of the scale inhibitor do not change much.

For example, if the flow rate between the branch point A and the junction point B of the water inlet pipe 64 increases, the pressure loss between them increases. Then, the pressure loss between the points AB increases, which means that the branch flow rate flowing through the circuit (point A → point C → point B) provided with the scale suppressing means 68 also increases. There is an almost constant trend. Moreover, since the dissolution amount of the scale inhibitor 67 when water is passed is approximately proportional to the flow rate, the characteristics shown in FIG.

  FIG. 3 shows a method of setting an arbitrary branch flow rate ratio. The figure (a) sets the pressure loss between the points AB by changing the flow resistance between the branch point A and the confluence point B of the water inlet pipe 64, and the ratio of the branch flow rate according to the differential pressure. Can be determined. Further, when the flow path resistance of the scale suppression means 68 is large, as shown in FIG. 5B, a configuration is adopted in which fluid dynamic pressure is applied to the circuit side provided with the scale suppression means 68, and point AB By changing the shape of the water inlet pipe 64 in between, the pressure loss between the points AB can be set, and the branch flow rate ratio can be determined according to the differential pressure.

  Thus, when the scale suppression means 68 filled with the scale inhibitor 67 is provided in parallel to the water inlet pipe 64, the ratio of the flow rate flowing to the scale suppression means 68 side at the branch point A becomes substantially constant. The concentration of the scale inhibitor 67 downstream from the junction B can be made substantially constant.

  As described with reference to FIG. 7, when the outside air temperature changes, such as seasonal changes, the city water temperature, which is the temperature of the tap water, also changes. As a result, the boiling flow rate changes, but as described above. In addition, since a stable concentration of the scale inhibitor 67 can be obtained without much influence of the boiling flow rate, useless consumption of the scale inhibitor 67 is eliminated, and the life of the scale inhibitor 67 is prolonged. There is an effect that maintenance and maintenance costs such as replacement and replenishment are reduced.

  Furthermore, as explained in FIG. 8, even when the incoming water temperature changes (rises) when the mixed layer portion is boiled, and the boiling flow rate changes (increases), a stable concentration of the scale inhibitor 67 can be obtained. Therefore, as described above, the consumption of the useless scale inhibitor 67 is eliminated, so that the life of the scale inhibitor 67 is prolonged, and there is an effect that maintenance and maintenance costs such as replacement and replenishment are reduced.

( Reference Example 1 )
FIG. 4 is a configuration diagram of a hot water supply apparatus in Reference Example 1 of the present invention. The difference from Embodiment 1 of FIG. 1 is that a flow rate adjusting means 69 is provided between the branch point A and the junction B of the water inlet pipe 64, and the control means 70 operates the flow rate adjusting means 69. Control. Other configurations are the same as those in FIG. As the flow rate adjusting means 69, for example, there is a flow rate control valve (not shown) generally used in a water heater, and the flow rate is changed by changing the cross-sectional area of the flow path through which the fluid passes by driving a stepping motor. Is to change.

  About the hot water supply apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. In FIG. 4, when the concentration of the scale inhibitor 67 downstream of the junction B is changed to a predetermined concentration, the flow path resistance of the flow rate adjusting means 69 is changed (for example, the flow path cross-sectional area is changed as described above). By changing the pressure loss between the branch point A and the junction point B, the ratio of the flow rate (branch flow rate) that branches and flows to the scale suppression means 68 side is changed.

  That is, when the flow path resistance of the flow rate adjusting means 69 is increased (for example, the flow path cross-sectional area is decreased), the pressure loss between the branch point A and the junction point B increases, so the ratio of the branch flow rate increases. The density | concentration of the scale inhibitor 67 of the downstream of the confluence | merging point B of the water intake pipe 64 can be enlarged. Conversely, when it is desired to reduce the concentration, the flow path resistance of the flow rate adjusting means 69 may be decreased (for example, the flow path cross-sectional area is increased).

For example, when using a region with high hardness water or well water for water supply, the concentration may be determined based on information from the hardness detection means 71 that detects the hardness of the water supply. If the hardness of the feed water is high, the control means 70 may adjust the flow rate adjusting means 69 in order to set the concentration to the ratio of the branch flow rate at which the scale is not generated.

  The hardness of the water supply may be directly input to the remote controller 72 of the hot water supply apparatus provided with the control means 70 by an input means (not shown). Furthermore, the relationship between the hardness of the water supply and the concentration of the scale inhibitor 67 that does not generate scale, the relationship between the flow path resistance of the flow rate adjusting means 69 and the concentration of the scale inhibitor 67, and the like are obtained in advance. Alternatively, it may be stored in the remote controller 72.

  In this way, when the hardness of the feed water is high, the concentration of the scale inhibitor 67 that does not generate scale can be set, so the life of the additive becomes longer than when using it at a high concentration for safety. This has the effect of reducing maintenance and maintenance costs such as replacement and replenishment.

  In addition, there is an effect that the service life of the hot water supply heat exchanger 52 is extended, and maintenance and maintenance costs such as replacement are reduced.

  The main factors that cause the scale to adhere to and grow in the hot water supply heat exchanger 52 include the aforementioned factors of the hardness of the water supply and the factors of the temperature stored in the hot water storage tank 57 (boiling temperature). The higher the boiling temperature, the greater the scale formation and growth. Therefore, the control means 70 adjusts the flow rate adjusting means 69 in order to obtain the concentration of the scale inhibitor 67 that does not generate and grow scale with respect to the boiling temperature, and to set the branch flow rate ratio to be this concentration. What is necessary is just composition.

  At this time, the relationship between the scale generation with respect to the boiling temperature and the concentration of the scale inhibitor 67 that does not grow may be obtained in advance, and this relationship may be stored in the remote controller 72.

  Thus, since the concentration of the scale inhibitor 67 that does not cause scale generation can be set according to the boiling temperature, the life of the scale inhibitor 67 is longer than that in the case of using a high concentration for safety. There is an effect that maintenance and maintenance costs such as replacement and replenishment are reduced.

  In addition, there is an effect that the service life of the hot water supply heat exchanger 52 is extended, and maintenance and maintenance costs such as replacement are reduced.

  The temperature (boiling temperature) stored in the hot water tank 57 is generally about 65 to 90 ° C. The higher the boiling temperature is, the larger the scale is generated and grown, but if it is around 65 ° C., the scale is generated little and there is almost no growth. In this case, the control means 70 may adjust the flow rate adjusting means 69 so that the concentration of the scale inhibitor 67 is minimized. That is, the flow path resistance of the flow rate adjusting means 69 is controlled to be the minimum (the flow path cross-sectional area through which the fluid of the flow rate adjusting means 69 passes is maximized).

  In this way, when the boiling temperature is such that there is little generation of scale and little growth, the concentration of the scale inhibitor 67 can be set to the minimum. In comparison, there is an effect that the life of the additive is prolonged, and maintenance and maintenance costs such as replacement and replenishment are reduced.

( Reference Example 2 )
FIG. 5 is a configuration diagram of a hot water supply apparatus in Reference Example 2 of the present invention. The difference from Embodiment 1 of FIG. 1 is that an opening / closing valve 73 is provided in series with the scale suppressing means 68 filled with the scale inhibitor 67, and the control means 70 controls the operation of the opening / closing valve 73. Other configuration is shown in FIG.
Since it is the same as that, description is abbreviate | omitted.

  About the hot water supply apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. In FIG. 5, when the on-off valve 73 is opened, the water in the lower part of the hot water tank 57 flows to both the points A and B side of the water inlet pipe 64 and the scale suppression means 68 side. Further, when the on-off valve 73 is closed, the water in the lower part of the hot water tank 57 flows only between the point A and the point B of the water inlet pipe 64 and does not flow to the scale suppressing means 68 side.

  As described above, when the boiling temperature is around 65 ° C., there is little generation of scale and almost no growth. In this case, since it is not necessary to consume the scale inhibitor 67, the control means 70 may be configured to close the on-off valve 73.

  Thus, when the boiling temperature is such that there is little generation of scale and little growth, it can be set so that the scale inhibitor 67 is not consumed. Compared to the above, there is an effect that the life of the additive is prolonged, and maintenance and maintenance costs such as replacement and replenishment are reduced.

  As described above, the hot water supply apparatus according to the present invention has a substantially constant concentration of the scale inhibitor even when the incoming water temperature changes, and can effectively suppress the generation of scale, so the life of the scale inhibitor is prolonged, Maintenance and maintenance costs such as replacement and replenishment can be reduced.

52 Hot water supply heat exchanger 55 Heat pump unit (heating means)
57 Hot water storage tank 64 Intake pipe 65 Hot water outlet 67 Scale inhibitor 68 Scale suppression means 69 Flow rate control means 73 On-off valve

Claims (3)

A hot water storage tank for storing hot water, a hot water heat exchanger for exchanging heat between the high-temperature refrigerant produced by the heating means and the water sent from the lower part of the hot water storage tank, the hot water supply heat exchanger and the lower part of the hot water storage tank, a water inlet pipe for connecting said a hot water pipe for connecting the hot water supply heat exchanger and the upper portion of the hot water storage tank, for suppressing scale inhibitor of scale formation provided in parallel to the entering water pipe Scale addition means for adding, even if the flow rate of water sent from the lower part of the hot water storage tank and heated to the predetermined temperature by the hot water supply heat exchanger changes, it is heated to the predetermined temperature by the hot water supply heat exchanger The ratio of the branch flow rate of the water flowing through the scale suppression means to the flow rate of the water to be generated and the dissolution concentration of the scale inhibitor of water heated to the predetermined temperature in the hot water supply heat exchanger are substantially constant. hot water, characterized by being configured to Location. The hot water supply apparatus according to claim 1 , wherein the scale inhibitor is polyphosphate. The hot water supply apparatus according to claim 1 or 2 , wherein the heating means is a heat pump unit.