JP2007085583A - Heat insulating structure of hot water storage tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent lowering of temperature of hot water in a hot water storage tank by inhibiting heat radiation from a heat insulated hot water storage tank surface, while securing a degree of freedom in piping and arrangement of functional components, and work efficiency in mounting a heat insulating material. <P>SOLUTION: This heat insulating structure of the hot water storage tank comprises the hot water storage tank and a housing receiving the hot water storage tank, and is constituted by placing the heat insulating material around the hot water storage tank, and further placing the heat insulating material on an inner face of the housing. Further a hot water supply tank has the heat insulating structure of the hot water storage tank where the piping and the functional components are placed in a space between the heat insulating material around the hot water storage tank and the heat insulating material on the inner face of the housing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat insulating structure of a hot water storage tank of a hot water storage hot water heater such as an electric water heater, a heat pump hot water heater, and a solar heat collecting hot water heater.

  Hot water storage water heaters use a method in which hot water boiled in an electric water heater or heat pump water heater is stored in a hot water storage tank. There is a need for improved hot water insulation performance. On the other hand, it is suitable for global environmental protection, can be reduced in cost by using cheap midnight power, and can be made into high-temperature water. In recent years, a heat pump using a carbon dioxide refrigerant as a heat source. Many hot water storage water heaters are beginning to be used. For this reason, the improvement of the heat retention performance of the hot water storage tank is increasingly important.

  FIG. 1 is an example of such a heat pump water heater system. Hot water boiled by the heat pump 20 is stored in a hot water storage tank 23 and stored in a heat-retaining state. The hot water in the hot water storage tank 23 is mixed with water so as to reach a desired temperature by the mixing valve 38 and then used in the bathtub 21. Or after mixing with water so that it may become desired temperature with the mixing valve 37, it is used with the hot-water tap of a shower or a kitchen.

  Conventionally, as a heat insulating structure for keeping hot water in the hot water storage tank 23, a foamed heat insulating material such as glass wool, foamed polyethylene, foamed polystyrene, or foamed polypropylene is attached to the surface of the hot water tank.

  FIG. 3 is an example of a structural diagram of a hot water storage tank that is also used conventionally. The surface of the hot water storage tank 2 is covered with a tank heat insulating material 3 and a copper pipe 7 connected to the hot water storage tank 2 is provided, and the periphery thereof is covered with a box-shaped or cylindrical housing 1 as shown in the figure. Generally, it has a broken structure. The material of the casing 1 is steel or the like.

  However, in such a heat insulating structure, although heat dissipation from the hot water storage tank can be prevented as compared with the case without the heat insulating material 3, since the housing 1 has no heat insulating material, the outside of the tank heat insulating material 3 is inside the housing. However, the outside air outside the casing is exposed to the same temperature, and the heat retention effect may not be sufficient. For this reason, when there is a large amount of hot water used in the winter season, there is a concern that the hot water will run out, and there is a problem that a large-capacity hot water storage tank is required and the cost of boiling the hot water accordingly. Therefore, in order to improve the heat insulation effect and the heat insulation effect, a heat insulating material made of a thermoplastic resin foam molded body is used so as to fill a space between the hot water storage tank and the casing, and the peripheral surface of the hot water storage tank and the inner surface of the heat insulating material are used. A method of forming a space between the two is known (Patent Document 1).

In addition, in the heat insulation structure of FIG. 3, heat radiation of the portion around the hot water tank 2 that is in contact with the heat insulating material can be prevented, but the piping provided from the hot water tank 2, the tank legs 4 that support the hot water tank 2, and the hot water tank 2 has little effect on heat dissipation from sheet metal parts, functional parts, and the like. Therefore, heat is released from the pipe by a method of winding a foamed heat insulating material such as polyethylene foam around the pipe portion where the heat dissipation is large (Patent Document 2), and a method of providing a pipe groove portion for storing the pipe in the molded heat insulating material (Patent Document 3). There are known ways to suppress it.
JP 2004-251521 A JP 2004-183934 A JP 2002-310511 A

  However, in the method of Patent Document 1, since a molded heat insulating material is used, when there are pipes or functional parts in the space between the hot water storage tank and the housing, it is difficult to mold in accordance with their shape and arrangement. There were restrictions on the arrangement of piping and functional parts. In addition, once the molding and the shape and arrangement of the functional parts are changed, they cannot be attached and there is a problem that there is no degree of freedom. As a result, there is a problem that productivity is poor and cost is high.

In the method of Patent Document 2, depending on the interval and routing of the piping, it is difficult to wind the heat insulating material, so that the workability is poor, or the heat insulating material cannot be wound, and consequently the heat insulating effect cannot be improved. There was a case.
Further, in the method of Patent Document 3, as in Patent Document 1, there is a problem that the arrangement of piping and functional parts is limited and the degree of design freedom is small.

  In view of the situation as described above, the present invention suppresses heat radiation from the surface of the insulated hot water storage tank while ensuring the degree of freedom of arrangement of piping and functional parts and workability when attaching a heat insulating material. It aims at suppressing the temperature fall of the hot water in a hot water storage tank.

(1) The present invention includes a hot water storage tank and a housing for storing the hot water storage tank, and a heat insulating material is disposed around the hot water storage tank, and a heat insulating material is disposed on the inner surface of the housing. Structure.
(2) In item (1), the heat storage structure of the hot water storage tank further includes a pipe arranged in a space between the heat insulating material attached around the hot water storage tank and the heat insulating material on the inner surface of the housing.
(3) In the item (1) or (2), the heat insulation structure of the hot water storage tank in which the functional parts are further arranged in the space between the heat insulating material attached around the hot water storage tank and the heat insulating material on the inner surface of the housing. It is.
(4) In any one of Items (1) to (3), the pipe is a heat insulating structure of a hot water storage tank covered with a heat insulating material.
(5) In any one of Items (1) to (4), the heat insulating material disposed around the hot water storage tank is a heat insulating structure of the hot water storage tank which is glass wool.
(6) In any one of the items (1) to (5), the heat insulating material disposed on the inner surface of the housing is a heat insulating structure of a hot water storage tank which is a foamed molded body.

  According to the present invention, the heat insulation structure of the hot water storage tank has a double heat insulation structure by the heat insulating material attached around the hot water storage tank and the heat insulating material on the inner surface of the housing, and the heat insulating material is provided on the inner surface of the housing. Even if heat is radiated from the heat insulating material provided around the hot water storage tank, this heat can be kept in a space formed between the heat insulating material of the hot water storage tank and the heat insulating material on the inner surface of the housing. That is, since the temperature of this space rises, the temperature difference from the heat radiating portion becomes smaller than in the conventional case, so the amount of heat radiated becomes small and the temperature drop of the hot water in the hot water storage tank can be suppressed.

  When piping and functional parts are placed in the space between the heat insulating material around the hot water storage tank and the heat insulating material on the inner surface of the housing, the heat dissipated from the hot water in the hot water tank to the piping and functional components is dissipated on the inner surface of the housing. Heat dissipation to the outside air can be suppressed by the heat insulating material. Moreover, since it is only arranged in space, there are few restrictions on arrangement of piping and functional parts, and the degree of freedom in design is large. In addition, it is possible to save the trouble of attaching a heat insulating material to each individual pipe or functional part, and workability is improved. Furthermore, the influence of the outside air temperature is alleviated by the heat insulating material on the inner surface of the housing, and freezing of the piping and functional parts inside the housing can be suppressed even in winter.

  In addition, when piping and functional parts are placed in a space between the heat insulating material around the hot water tank and the heat insulating material on the inner surface of the housing, the heat insulating performance of the hot water tank is further improved when heat insulating material is attached to the piping. To do.

  In addition, by using a plate-shaped foam molded body as the heat insulating material placed on the inner surface of the housing, it is possible to remove the piping and functional parts during maintenance so that the piping and functional parts can be handled by removing the exterior as in the conventional case. In addition, heat retention can be improved without impairing workability.

  The heat insulation structure of the hot water storage tank used in the present invention is a structure in which a heat insulating material is attached to the hot water storage tank and the periphery thereof, and a space sandwiched between the heat insulating materials is formed between the heat insulating material attached inside the housing. By providing the heat insulating material on the inner surface of the housing in this way, even if heat is radiated from the heat insulating material provided around the hot water storage tank, this heat can be generated between the heat insulating material of the hot water storage tank and the heat insulating material on the inner surface of the housing. It is possible to keep it on. That is, since the temperature of this space rises, the temperature difference from the heat radiating portion becomes smaller than in the conventional case, so the amount of heat radiated becomes small and the temperature drop of the hot water in the hot water storage tank can be suppressed.

The space in the heat insulating structure of the present invention is preferably as narrow as possible in order to suppress heat radiation from the air in the space. However, since the hot water storage tank is usually accompanied by piping and functional parts, the space is preferably wide enough to accommodate these. By arranging piping and functional parts connected to the hot water storage tank in this space, it is possible to suppress the heat radiation from the hot water in the hot water storage tank to the piping and functional parts from being released to the outside air by the heat insulating material on the inner surface of the housing. it can. Due to the heat radiation from the piping and the functional parts, the air in the space is warmed, and the heat radiation from the heat insulating material of the hot water storage tank can be further suppressed.
Further, in the present invention, since only the space is provided, it is not necessary to form a heat insulating material in accordance with individual pipes and functional parts, and to provide a groove for storing them, so that common parts can be used, and production costs can be used. Can be reduced. Moreover, since it is not necessary to attach a heat insulating material for every piping or functional component, workability | operativity improves. In addition, there are few restrictions on the arrangement of piping and functional parts, and the degree of freedom in design is great. Furthermore, the influence of the outside air temperature is mitigated by the heat insulating material inside the housing, and freezing of the piping and functional parts inside the housing can be suppressed even in winter.

  The piping in the space in the present invention is preferably provided with a heat insulating material such as polyethylene foam in a place where heat radiation is large, such as in the vicinity of a connecting portion with a hot water storage tank. For example, when hot water boiled from a heat collector such as a heat pump is stored in a hot water storage tank, a heat insulating effect is increased by attaching a heat insulating material directly to the piping. Thereby, the heat retention can be further improved.

It is preferable to attach a heat insulating material directly to the functional part in the said space in this invention in the place where heat dissipation is large similarly to the piping mentioned above. Thereby, the heat retention can be further improved.
However, for example, a control board for controlling hot water supply, pouring, boiling, etc. is not preferable in terms of reliability to be exposed to a high ambient temperature. It is preferable to take cooling measures.

  The hot water storage tank used in the present invention is the same as that generally used in electric water heaters, heat pump water heaters and the like, and does not require any special material or shape. For example, a cylindrical or box-shaped one using stainless steel or the like can be used.

  The casing used in the present invention is intended to prevent the inside of the tank water heater from being exposed to rain, wind, and the like, but also functions to support the hot water storage tank. For this reason, a steel plate, a resin material, etc. are used for the material from a viewpoint of weather resistance, corrosion resistance, and mechanical strength. In addition, the shape of the casing is not limited as long as it can cover the hot water storage tank, but since a heat insulating material is attached to the inside of the casing, it can be assembled into a cylindrical or box-shaped part considering its workability. It is preferable.

  The functional parts in the present invention include a three-way valve, a solenoid valve, a flow sensor, a water level sensor, a water flow switch, a circulation pump, etc. in the conventional usage example, and a connection part is provided in the piping path according to the function of the hot water tank. Used.

  The material of the heat insulating material around the hot water storage tank in the present invention is not particularly limited as long as it is generally used for keeping the hot water storage tank warm. If the thermal conductivity is low and the thickness is large, the higher heat insulation can be obtained. For this reason, it is preferable to use glass wool that is flexible, easily wound around the hot water storage tank, and inexpensive. In addition, rock wool, polystyrene foam, expanded polystyrene, rigid urethane foam, expanded polystyrene, phenolic foam, expanded glass, calcium carbide, vegetable fiber insulation such as cork and cellulose, animal insulation such as wool, etc. In addition, a vacuum heat insulating material or the like can also be used.

  The method of attaching the heat insulating material around the hot water storage tank in the present invention can be attached by winding and fixing the hot water storage tank in the case of flexible glass wool or the like. In the case of a foam molded heat insulating material or the like, it can be attached by fitting and fixing a hot water storage tank that is molded in accordance with the shape of the hot water storage tank.

  The thickness of the heat insulating material around the hot water storage tank in the present invention takes into account the heat retention, the cost of the heat insulating material, and ensuring the space for the piping and functional parts to fit in the space with the heat insulating material on the inner surface of the housing. Set. The thickness of the heat insulating material is preferably used between 10 and 100 mm, although it varies depending on the thermal conductivity of the heat insulating material when applied to the hot water storage tank and the outer dimensions of the case of a general hot water tank type water heater. . Furthermore, considering the downsizing of the housing, securing of the amount of stored hot water, and heat retaining performance, 30 to 70 mm is preferable.

  In order to suppress heat dissipation, it is desirable that the heat insulating material mounting range around the hot water storage tank in the present invention be provided on the entire surface around the hot water storage tank and the entire inner surface of the housing. In consideration of the balance between cost, workability, and heat retention effect, it is possible not to provide it on the bottom of the hot water storage tank, etc., but to cover at least half of the area from the top of these. desirable. Since the temperature of the upper part of the hot water storage tank is high, it is possible to improve the heat retaining effect while reducing the cost of the heat insulating material by suppressing the heat radiation from here.

  The material of the heat insulating material on the inner surface of the housing in the present invention can be the same as the heat insulating material around the hot water storage tank described above.

  The method of attaching the heat insulating material on the inner surface of the housing in the present invention can use the same method as the heat insulating material around the hot water storage tank described above, but heat insulating by spraying a plate-like foam molded heat insulating material or urethane foam. Is preferable from the viewpoint of efficient work. Moreover, it is preferable to affix for every component of a housing | casing from the point of workability | operativity, such as a front heat insulating material, a left-right side heat insulating material, a back heat insulating material, a top heat insulating material, and a bottom heat insulating material.

In the present invention, the attachment range of the heat insulating material on the inner surface of the housing does not necessarily need to be the entire surface within the housing. For example, since the bottom of the housing is connected to the hot water storage tank leg and the workability of the attachment is poor, when priority is given to this workability, it is not necessary to attach the heat insulating material to the bottom of the inner surface of the housing. Even in this case, the temperature of the space can obtain a heat retaining effect because high temperature air convects upward.
In addition, for example, in order to improve maintenance and workability, piping is generally concentrated on the front surface of the tank. It is not necessary to attach a heat insulating material. The space surrounded by the heat insulating material is formed around the piping part on the front surface of the hot water tank by having the left and right side heat insulating materials, the tank upper heat insulating material and the heat insulating material around the hot water tank in close contact or narrowing the gap. it can.
In addition, for example, it is difficult to attach heat insulating material to the part where the legs supporting the tank and the sheet metal parts supporting the case are directly connected to the case. It's okay.

  Examples of the present invention will be described below together with comparative examples based on the results of the heat retention performance test.

  FIG. 2 is a cross-sectional view of the heat insulation structure of a hot water storage tank according to one embodiment of the present invention. It was set as the structure which affixed the heat insulating material to the inner side of the housing | casing 1 installed on the concrete block 10, and the circumference | surroundings of the hot water storage tank 2. FIG.

  FIG. 3 is a cross-sectional view of a comparative example of the present invention. Although the heat insulating material is not attached at all to the inside of the housing 1 installed on the concrete block 10, the structure in which the heat insulating material is pasted around the hot water storage tank 2 is the same as the above embodiment. It is.

The hot water storage tank 2 is used for a general hot water storage type hot water heater in both of the examples and the comparative examples, and has a cylindrical shape (cylinder diameter 383 mm, height 1668.6 mm) and a capacity of 185 l. Glass wool (thickness 50 mm, density 24 kg / m ³ ) was attached as a heat insulating material 3 by wrapping around the hot water storage tank around almost the entire surface of the hot water storage tank. Since the glass wool, which is a heat insulating material, is light and flexible, it was easy to wrap around the hot water storage tank 2 and attach it.

The casing 1 uses a steel plate (thickness 0.6 mm) in both the example and the comparative example, and the dimensions are as shown in FIG. This was installed on a concrete block. About only the Example, the glass wool (thickness 25mm, density 24kg / m < ³ >) was attached as the heat insulating material 9 on the substantially whole surface inside the housing | casing 1 by affixing. Since this glass wool is easily cut and flexible, it can be easily attached to the inner surface of the housing.

  The pipes 5 and 7 were made of copper material (thickness 0.7 mm, pipe diameter 16 mm) in both the examples and comparative examples, and the functional component 8 was a three-way valve.

  Using these examples and comparative examples, a heat retention test was performed. The test method is as follows. Store 75 ° C hot water in a tank in a full tank (185 l). Surfaces (1) to (5) of hot water storage tank 2 shown in FIG. 5, functional component 8 (three-way valve) (6), pipe surfaces (7) and (8), and inside the housing (9) shown in FIG. The temperature sensor for measuring temperature was attached to the position of (11). The result of having measured each temperature change at the time of hold | maintaining for 13 hours on the conditions of environmental temperature 10 degreeC is shown to FIGS. FIG. 7 shows the average temperature of the tank surface temperatures (1) to (5). FIG. 8 shows the average temperature of the housing internal temperatures (9) to (11). FIG. 9 shows the average temperature of the pipes (7) and (8) and the temperature of the functional component (three-way valve) (6).

  From FIG. 7, it was found that the tank average temperature was higher in the example than in the comparative example and was excellent in the heat retention of the hot water storage tank. Assuming that the temperature of the water to be mixed is 15 ° C. after 13 hours, the difference in heat insulation performance is about 2 ° C. In the case of the capacity of the hot water storage tank used for the test (185 l), It is estimated that the amount of hot water supply will increase by about 13 liters as hot water of 42 ° C per day. If the capacity of the hot water storage tank is increased, the amount of hot water supply is further increased, and it is possible to prevent hot water from running out and to reduce running costs.

  From FIG. 8, it can be seen that the temperature inside the case is higher in the example than in the comparative example, and the surface temperature of the pipe 7 and the functional component 8 (three-way valve) is shown in FIG. The example was found to be higher than the comparative example. From the results of FIGS. 8 and 9, in the heat insulating structure of the embodiment, there is an action to keep the amount of heat due to heat radiation from the tank, the pipe, the tank leg, and the like inside the casing, thereby the pipe 7 and the functional component 8 ( It was confirmed that the three-way valve) had the effect of obtaining the heat retaining effect.

It is an example of a heat pump type water heater system. It is sectional drawing of the heat insulation structure of the hot water storage-type tank which is one Example of this invention. It is an example (comparative example) of the heat insulation structure of the conventional hot water storage tank. It is an example of the housing | casing used for the exterior of a hot water storage-type tank. This is the temperature measurement point on the surface of the hot water storage tank in the heat insulation test. It is the temperature measurement location inside the housing in the heat retention test. It is a time-dependent change of the average temperature of the hot water storage tank surface in a heat retention test. It is a time-dependent change of the average temperature inside a housing in a heat retention test. It is the change over time of the surface temperature of piping and functional parts in the heat insulation test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Housing | casing, 2 ... Hot water storage tank, 3 ... Tank heat insulating material, 4 ... Tank leg, 5 ... Drain copper pipe, 6 ... Water stop cock, 7 ... Copper piping, 8 ... Three-way valve, 9 ... Housing inner surface heat insulating material, DESCRIPTION OF SYMBOLS 10 ... Concrete block, 20 ... Heat pump, 21 ... Bath, 22 ... Drain plug, 23 ... Hot water storage tank, 24 ... Reheating heat exchanger, 25 ... Circulation pump, 26 ... Three-way valve, 27 ... Relief valve, 28 ... Three-way valve , 29 ... Solenoid valve, 30 ... Three-way valve, 31 ... Water flow switch, 32 ... Circulation pump, 33 ... Water level sensor, 34 ... Check valve, 35 ... Pressure reducing valve, 36 ... Hot water tap, 37 ... Mixing valve, 38 ... Mixing Valve, 39 ... housing

Claims (6)

  A heat insulation structure for a hot water storage tank comprising a hot water storage tank and a housing for housing the hot water storage tank, wherein a heat insulating material is disposed around the hot water storage tank, and a heat insulating material is disposed on the inner surface of the housing.   2. The heat insulation structure for a hot water storage tank according to claim 1, further comprising a pipe disposed in a space between the heat insulating material attached around the hot water storage tank and the heat insulating material on the inner surface of the housing.   The heat insulation structure of a hot water storage tank according to claim 1 or 2, further comprising a functional component disposed in a space between the heat insulating material attached around the hot water storage tank and the heat insulating material on the inner surface of the housing.   4. The heat insulation structure of a hot water storage tank according to claim 1, wherein the piping is covered with a heat insulating material.   The heat insulation structure of the hot water storage tank according to any one of claims 1 to 4, wherein the heat insulating material arranged around the hot water storage tank is glass wool. The heat insulation structure of the hot water storage tank according to any one of claims 1 to 5, wherein the heat insulating material disposed on the inner surface of the casing is a foam molded body.

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