JP2011085314A - Water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water heater improving heating efficiency. <P>SOLUTION: The water heater includes a hot water storage tank 1 and a heat exchanger 9 having a flow passage 9a arranged within the hot water storage tank 1 and exchanging heat between hot water within the hot water storage tank 1 and hot water made to flow within the flow passage 9a, and the flow passage 9a is arranged to form an approximately mortar shape with an opening area enlarged downwardly. A descending water flow generated around the flow passage 9a of the heat exchanger 9 provided within the hot water storage tank 1 is minimized to suppress stirring action within the hot water storage tank 1, and decline in usable hot water amount caused by expansion of a mixing layer can be prevented, so as to achieve excellent usability and high energy saving performance. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hot water supply apparatus that stores hot water in a hot water storage tank and uses it for hot water supply, or uses the retained heat.

  Conventionally, this kind of hot water supply apparatus has a thing like FIG. 7, for example (for example, refer patent document 1).

  FIG. 7 shows a conventional hot water supply apparatus described in Patent Document 1. As shown in FIG. As shown in FIG. 7, a hot water tank 1 and a serpentine tube 2 as a heat exchanger are provided in the hot water tank 1, and the water in the bathtub 3 is circulated through the serpentine tube 2 to reheat the bath. It is said.

JP 2003-214711 A

  However, in the conventional configuration using the serpentine tube 2 in the heat exchanger, when water from the bathtub is circulated through the serpentine tube 2, the hot water in the hot water storage tank around the serpentine tube 2 is lowered and a water flow is generated. As shown in FIG. 8, the water flow is gradually accelerated along the serpentine tube 2 (the length of the arrow indicates the flow velocity), and the descending water flow having increased speed travels downward in the hot water tank 1.

  Here, in this type of hot water supply apparatus that forms a temperature stratification and stores hot water, the hot water 3 and the water 4 are brought into contact with each other in the hot water storage tank 1 in the process of using the hot water, and the layer 5 (hereinafter referred to as the mixed layer). 5), but the descending water stream reaches this layer 5 and has a stirring action.

  Then, since the mixed layer 5 becomes large and the hot water temperature stored is lowered more than necessary, the amount of available hot water is reduced. At the same time, the water temperature below the mixed layer 5 also rises. This means that at the next boiling time, water having a higher temperature must be heated, and when a heat pump is used as the heating means 6, there is a characteristic that operation efficiency is lowered when the water temperature is high. For this reason, there is a problem that it hinders efficient driving.

  Thus, in the heat exchanger in which the flow path is arranged in the height direction in the hot water storage tank 1 like the serpentine tube 2, the amount of hot water that can be used is reduced due to the expansion of the mixed layer 5, and at the time of boiling by the heat pump There was a problem of reduced efficiency.

  This invention solves the said conventional subject, and it aims at providing the hot-water supply apparatus which improved the heating efficiency.

  In order to solve the conventional problems, a hot water supply apparatus of the present invention includes a hot water storage tank, a hot water tank disposed in the hot water storage tank, hot water in the hot water tank, and hot water flowing in the flow path. A heat exchanger for exchanging heat, and the flow path is disposed in the hot water storage tank so as to have a substantially mortar shape with a large opening area in the downward direction. The falling water flow generated inside can be minimized, and the stirring action of the mixed layer can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the hot water supply apparatus which improved the heating efficiency can be provided.

Configuration diagram of hot water supply apparatus in Embodiment 1 of the present invention Top view of the heat exchanger Figure showing temperature distribution in the hot water tank Figure showing the flow velocity near the heat exchanger Plan view of heat exchanger with the same shape Plan view of heat exchanger with the same shape Configuration diagram of conventional hot water supply equipment Figure showing the flow velocity near the heat exchanger

  1st invention is equipped with the hot water storage tank and the heat exchanger which has a flow path arrange | positioned in the said hot water storage tank, and heat-exchanges the hot water in the said hot water storage tank, and the hot water flowing in the said flow path, A flow path of a heat exchanger provided in the hot water storage apparatus, wherein the flow path is disposed in the hot water storage tank so as to have a substantially mortar shape with a large opening area in the downward direction. Minimizing the downward water flow that occurs in the surrounding area to suppress the stirring action in the hot water tank and prevent the decrease in the amount of hot water that can be used due to the expansion of the mixed layer, realizing good usability and high energy savings There is an effect that can be done.

  The second invention is characterized in that, in particular, the heat exchanger channel of the first invention is formed in a spiral shape, and it is easy to fit into a cylinder which is a general hot water tank shape. There is.

  The third invention is characterized in that, in particular, the flow path of the heat exchanger of the first invention is formed by a plurality of straight portions and a plurality of bent portions, and according to the shape of the hot water tank, There is an effect that the road can be arbitrarily configured.

  The fourth invention is characterized in that, in particular, the flow path of the heat exchanger of any one of the first to third inventions is formed by a single path, realizing a simple configuration, leakage, etc. There is an effect that can realize high reliability with less.

  In the fifth invention, the flow path of the heat exchanger according to any one of the first to third inventions is branched into a plurality of flow paths in the vicinity of the water inlet in the hot water tank, and is connected in the vicinity of the water outlet This is characterized in that the required flow path length, pressure loss, and heat passage rate can be appropriately designed.

  The sixth invention is characterized in that, in any one of the first to fifth inventions, a heating means for heating water in the hot water tank is provided, and a heat pump cycle is used as the heating means. The use efficiency of energy is improved, and a hot water supply device excellent in energy saving can be realized.

  In a seventh aspect of the invention, the heat pump cycle of the sixth aspect of the present invention is a supercritical refrigerant circuit in which the pressure is equal to or higher than the critical pressure, and water is heated by the refrigerant whose pressure is increased to the critical pressure or higher. Since the temperature can be increased, it is possible to increase the amount of heat that can be used and to prevent the hot water from running out.

  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 diagram showing a configuration of a hot water supply apparatus according to the first embodiment of the present invention.

  In FIG. 1, a hot water tank 1, a heat pump unit 6 as a heating means for heating the water in the hot water tank 1, and a lower part of the hot water tank 1 that sends water before heating to the heat pump unit 6. 1 pipe 7, a second pipe 8 connected to the upper part of the hot water tank 1 for returning the heated water from the heat pump unit 6 to the hot water tank 1, and a bath chase provided above the hot water tank 1. A heat exchanger 9 for watering, a third pipe 11 for sending the water in the bathtub 10 and the bathtub 10 to the heat exchanger 9, and a fourth for returning the water after heat exchange from the heat exchanger 9 to the bathtub 10 A pipe 12, a hot water tap 13, a hot water supply pipe 14 connected to the upper part of the hot water tank 1 for supplying hot water to the hot water tap 13, and a hot water supply pipe connected to the lower part of the hot water tank 1 and the hot water supply pipe 14 via the mixing valve 15. It consists of piping 16.

  The hot water tank 1 is provided with a first connector 17 and a second connector 18 in order to connect the heat exchanger 9 to the third pipe 11 and the fourth pipe 12.

  FIG. 2 is a plan view of the heat exchanger 9 in the hot water tank 1, and the main body is a spirally wound channel 9 a that is a stainless steel tube. The outer end is connected to the third pipe 11 via the first connector 17, and the inner end is connected to the fourth via a second connector 18 (shown in FIG. 1) provided on the hot water tank 1. The pipe 12 is connected.

  The flow path 9a arranged on the outermost side keeps a substantially constant distance from the inner surface of the hot water tank 1, and the flow path 9a located on the inner side does not have an interval along the outer flow path 9a in order. In addition, the adjacent flow paths 9a are arranged in a substantially mortar shape with a larger opening area toward the lower side of the hot water tank 1, that is, the inner side is higher than the outer side.

  About the hot water supply apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  As a basic operation, the hot water tank 1 is filled with a lot of low-temperature water before boiling, and when the operation is started, the water in the hot water tank 1 is sent to the heat pump unit 2 through the first pipe 7. The heated hot water is returned to the hot water tank 1 through the second pipe 8. As a result, hot water is stored in the hot water tank 1.

  When hot water is used after boiling, hot water in the hot water storage tank 1 is sent through the hot water supply pipe 16, and this hot water is mixed to the set temperature by the water supply from the water supply pipe 16 and the mixing valve 15, and the hot water tap 13. Supplied from Further, water corresponding to the amount of hot water used for hot water supply flows from the lower part of the hot water tank 1 through the water supply pipe 16.

  When the bath water is heated, the water in the bathtub 10 is sent to the heat exchanger 9 through the third pipe 11 and is circulated in the hot water tank 1 through the flow path 9a of the heat exchanger 9 to thereby store the hot water tank. The water whose temperature has risen due to heat exchange with the hot water in 1 is returned to the bathtub 10 through the fourth pipe 12.

  In the above operation, the hot water tank 1 in use is in a state in which the hot water 3 and the low temperature water 4 are stacked, and an intermediate temperature between the hot water 3 and the water 4 due to heat conduction or convection. A mixed layer 5 is present.

  FIG. 3 explains the difference in the amount of available hot water depending on the size of the mixed layer 5. The temperature distribution of the hot water in the hot water storage tank 1 when the horizontal axis is the temperature and the vertical axis is the hot water storage tank 1 height is shown. Reference numeral 19 denotes a temperature distribution of the mixed layer 5a in a small state, and 20 denotes a temperature distribution of the mixed layer 5b in a large state.

  For example, when the temperature ts is the lower limit of the temperature at which hot water can be used, the difference in the amount of heat that can be used is schematically represented as the region 21, and the larger the mixed layer 5, the easier the hot water runs out. That is, there is low energy-saving property.

  Comparing the lower portions of the mixed layers 5a and 5b, the water temperature of the mixed layer 5b is often higher, and this means that hot water enters the heat pump unit 6 at the next boiling. Since the efficiency of the heat pump unit 6 increases as the water temperature before boiling increases, the large mixed layer 5 at the time of boiling impairs energy saving.

  FIG. 4 shows a cross section of the heat exchanger 9 in the hot water tank 1. Since the flow path 9a of the stainless steel tube constituting the heat exchanger 9 is arranged in a lower position in order toward the outside in the hot water storage tank 1, the water flow generated on the upper side of the pipe is gradually accelerated while the hot water storage tank 1 It reaches near the inner surface and descends along the inner surface.

  Since this water flow passes through the outermost side of the hot water tank 1, the mixing with the hot water remaining on the mixed layer 5 is small and reaches the mixed layer 5. Further, even when the mixture layer 5 is reached, stirring occurs at the peripheral portion, so that the action of expanding the mixture layer 5 is relatively small.

  On the other hand, the lower precipitation flow below the pipe descends almost uniformly with a small flow velocity. This water flow hardly affects each other, and the water flow is lowered in the hot water tank 1 with a small flow rate, and the influence on the mixed layer 5 is small.

  In this way, by suppressing the adverse effect caused by the descending water flow generated around the flow path 9a of the heat exchanger 9 provided in the hot water tank 1, the stirring action in the hot water tank 1 is suppressed, and the mixed layer 5 is enlarged. Since it is possible to prevent a decrease in the amount of hot water that can be used and a decrease in boiling efficiency in the heat pump unit 2, it is possible to achieve good usability and high energy savings.

  Further, the heat exchanger 9 is formed in a substantially circular spiral shape, so that there is an advantage that it is easy to match the shape of the cylindrical hot water tank 1 and a necessary tube length is easily secured.

  The flow of water in the heat exchanger 9 is from the outside to the inside of the flow path, but in the reverse direction, that is, the inlet is the second connector 18 side and the outlet is the first connector 17 side, from the inside to the outside. However, the same effect can be obtained.

  Furthermore, the refrigeration cycle of the heat pump unit 6 preferably uses carbon dioxide as a refrigerant and is operated at a pressure exceeding the critical pressure. Since the boiling temperature can be increased by using carbon dioxide as a refrigerant, the hot water temperature in the hot water tank 1 can be freely controlled.

  FIG. 5 shows a heat exchanger 9 which is formed into a substantially rectangular shape by forming a flow path 9a with a straight portion and a bent portion. In this case, the heat exchanger 9 can be applied to the rectangular hot water tank 1.

  Further, FIG. 6 shows that the heat exchanger 9 is provided with a first branch portion 22 near the inlet of the water flowing in the heat exchanger 9 in the hot water tank 1 and a second branch portion 23 near the outlet. The flow path can be divided into two systems, and the relationship between the flow path length, the pressure loss, and the heat passage rate can be appropriately designed.

As described above, the hot water supply device according to the present invention minimizes the decrease in the amount of hot water that can be supplied when using the heat of hot water in the hot water storage tank, so that it can be applied to the above-mentioned domestic hot water supply devices. In addition, it can be applied to large-scale applications such as business use in a system having a heat source and a hot water tank, and can provide excellent energy saving.

1 Hot water storage tank 6 Heating means (heat pump unit)
9 Heat exchanger 9a Flow path 10 Bathtub

Claims (7)

A hot water storage tank, and a heat exchanger disposed in the hot water storage tank and having a flow path, for exchanging heat between hot water in the hot water storage tank and hot water flowing in the flow path, A hot water supply apparatus, which is disposed in a hot water storage tank so as to have a substantially mortar shape with a large opening area in a downward direction. The hot water supply apparatus according to claim 1, wherein the flow path of the heat exchanger is formed in a spiral shape. The hot water supply apparatus according to claim 1, wherein the flow path of the heat exchanger is formed by a plurality of straight portions and a plurality of bent portions. The hot water supply apparatus according to any one of claims 1 to 3, wherein the flow path of the heat exchanger is formed by a single path. The flow path of the heat exchanger is branched into a plurality of flow paths in the vicinity of the water inlet in the hot water tank, and is connected in the vicinity of the water outlet. The hot water supply device described in 1. The hot water supply apparatus according to any one of claims 1 to 5, wherein a heating means for heating water in the hot water storage tank is provided, and a heat pump cycle is used as the heating means. The hot water supply apparatus according to claim 6, wherein the heat pump cycle is a supercritical refrigerant circuit.

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