JP2004162983A - Heat pump built-in type hot water storage water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water storage type water heater capable of supplying the hot water of a desired temperature without cooling the hot water to 30°C once by supplying the water even when the temperature of the hot water in the hot water storage tank is within the range of about 30-40°C which is lower than the desired hot water supply temperature. <P>SOLUTION: This hot water storage water heater 30 is composed of a solar heat collector 1 and a hot water storage tank 2 connected through a heat exchanging system. The heat exchanging system comprises the following heat pump cycles (a)-(d) to raise and keep the temperature of the hot water in the hot water storage tank 2 at a high temperature. The heat pump cycle comprises (a) pumping up the heat collected by the solar heat collector 1 by an evaporator 11 by using a refrigerant (gasification of refrigerant), (b) raising a pressure and a temperature of the refrigerant gas by a compressor (operated by commercial power source) 12, (c) pumping up the heat by a condenser 13 mounted at the hot water storage tank side (liquefaction of refrigerant gas), and (d) expanding the liquefied refrigerant by an expansion valve 14. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat pump hot water storage water heater that can raise and maintain the temperature of hot water stored in a hot water storage tank to a temperature higher than a desired temperature even in the case of rainy weather or cloudy weather when solar radiation is insufficient in winter or hot water, and can supply hot water to a desired temperature. It is.
[0002]
[Prior art]
FIG. 3 is an example of a conventional (solar heat utilization type) hot water supply / hot water supply device. This hot water storage water heater includes a solar heat collector 1 installed in a sunny place such as on a roof and a hot water storage tank 2 installed on the ground, and an auxiliary heat source such as an instantaneous water heater is provided downstream of the hot water storage tank 2. Vessel 7 is arranged. A circulation path is formed between the hot water storage tank 2 and the solar heat collector 1 via circulation pipes (an outgoing pipe 3a and a return pipe 3b), and the circulation path is filled with a heat medium. When there is solar radiation, the circulation pump 4 is operated to circulate the heat medium heated by the solar heat collector 1, and the water in the hot water storage tank 2 is indirectly transferred through the heat exchanger 6 provided inside the hot water storage tank 2. Warm up. If the temperature of the hot water in the hot water storage tank 2 does not rise in rainy or cloudy weather or in winter when sunshine is insufficient, the auxiliary hot-heater (instantaneous water heater) 7 heats and reheats the hot water to supply hot water.
[0003]
[Problems to be solved by the invention]
However, in the case of the above-described auxiliary hot-water supply type hot water storage water heater, since the minimum temperature rise (heat amount) of the auxiliary heat source is not small, the temperature of the hot water in the hot water storage tank 2 is slightly lower than the desired hot water supply temperature ( When the temperature is in the range of about 30 to 40 ° C., the temperature of the hot water from the hot water storage tank 2 is temporarily diluted with water to lower the temperature to about 30 ° C. In addition, additional heating must be performed in the auxiliary heat source 7 to raise the temperature to the desired temperature, and hot water supply and automatic hot water filling must be performed. Therefore, energy is wasted.
[0004]
The present invention provides a hot water storage water heater that can supply hot water at a desired hot water supply temperature without using an auxiliary heat source device such as an instantaneous water heater, that is, the temperature of hot water in a hot water storage tank is less than about 30 lower than the desired hot water supply temperature. It is an object of the present invention to provide a hot-water storage water heater that can supply hot water to a desired hot-water supply temperature without reducing the temperature to about 30 ° C. even when the temperature is in the range of −40 ° C.
[0005]
[Means for Solving the Problems]
To achieve the above object, the present invention has the following configuration. That is, the present invention firstly
The solar heat collector 1 and the hot water storage tank 2 are a hot water storage water heater 30 connected via a heat exchange system, and the heat exchange system includes a heat pump (or heat pump cycle) of the following a) to d). A heat pump hot water storage / water heater 30 that is provided and can raise and maintain the temperature of hot water in the hot water storage tank 2 to a high temperature.
Heat pump cycle:
a) Pumping (low-quality) heat collected by the solar heat collector 1 using a refrigerant in the evaporator 11 (gasification of the refrigerant);
b) The refrigerant gas is pressurized and heated by a compressor (usually operated by a commercial power supply) 12;
c) Pumping heat in the condenser 13 provided on the hot water storage tank side (liquefaction of refrigerant gas);
d) The liquefied refrigerant is expanded by the expansion valve 14.
[0006]
Here, instead of the solar heat collector 1, a waste heat recovery unit of a cell unit or a reforming unit in a fuel cell, a solar cell, or the like can be used.
That is, the present invention relates to a hot-water storage water heater 40 in which a heat generation unit (low-quality heat such as exhaust heat) and the hot-water storage tank 2 are connected via a heat exchange system. The heat pump (or heat pump cycle) of a) to d) is also provided, and the heat pump type hot water storage / water heater 40 is capable of raising and maintaining the temperature of hot water in the hot water storage tank 2 at a high temperature.
Heat pump cycle:
a) Pumping up the heat generated in the heat generating section using a refrigerant in the evaporator 11 (gasification of the refrigerant);
b) The refrigerant gas is pressurized and heated by the compressor 12;
c) Pumping heat in the condenser 13 provided on the hot water storage tank side (liquefaction of refrigerant gas);
d) The liquefied refrigerant is expanded by an expansion valve.
The heat generation unit is a waste heat recovery unit of a cell unit or a reforming unit in a fuel cell, a solar cell, or the like.
[0007]
The evaporator in the heat pump cycle is a device (low-temperature side heat exchanger) having the function of pumping heat energy from the solar heat collector 1 into a refrigerant in the form of latent heat of evaporation, and the condenser is a refrigerant. A high-temperature heat exchanger that heats the hot water in the hot water storage tank with the sensible heat and latent heat of condensation of the gas.
[0008]
[Action]
The hot-water storage water heater of the present invention does not use an auxiliary heat source device such as an instantaneous water heater, but instead uses heat pumping by a heat pump (the energy source is a commercial power supply), and the hot-water temperature of the hot-water storage tank becomes the desired hot-water supply temperature. Even when the temperature is lower than about 30 to 40 ° C., it can be heated directly to a desired hot water supply temperature or higher without being diluted with water and lowered to about 30 ° C., so that there is no waste of energy.
In the heat pump evaporator (low-temperature heat exchanger) used here, hot water heated by a solar heat collector, waste heat from a solar cell, fuel cell, etc., or an unstable heat generator is used as an energy source. Since low-quality heat from the water is used, the difference in pumping temperature can be reduced as compared with pumping from the ambient temperature, and the energy efficiency of the heat pump cycle increases.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the accompanying drawings.
FIG. 1 shows an example of a heat pump built-in type (using a solar heat collector) of the present invention. As shown in the figure, on the solar water heater side, a solar heat collector 1 for collecting solar energy, a buffer tank 5 for a heat medium, a circulation pump 4 for forcibly circulating the heat medium, and an evaporator (low-temperature heat exchanger). A heating medium 11 is forcibly circulated in a circulation path connected by the going pipe 3a and the returning pipe 3b. And
a) The low-quality heat collected by the solar heat collector 1 is pumped up by a refrigerant in an evaporator (low-temperature side heat exchanger) 11 (gasification of the refrigerant).
Then,
b) The refrigerant gas is pressurized and heated by a compressor (usually operated by a commercial power supply) 12;
c) Pump up heat in a condenser (high-temperature side heat exchanger) 13 provided on the hot water storage tank side (liquefy refrigerant gas);
d) expanding the liquefied refrigerant with an expansion valve 14;
With the heat pump constituting the above heat pump cycle, the hot water in the hot water storage tank is heated in the condenser (high temperature side heat exchanger) 13 by the sensible heat of the refrigerant gas and the latent heat of condensation by the electric energy from the commercial power supply.
[0010]
A water supply pipe 15 from a water supply source is arranged below the hot water storage tank 2, a bypass pipe 16 branches from the water supply pipe 15, and a hot water storage tank outlet side pipe 17 is connected to an upper part of the hot water storage tank 2. A hot / water mixing three-way valve 18 is provided at the junction of the hot water storage tank outlet pipe 17 and the bypass pipe 16 so that hot water can be supplied at a desired hot water supply temperature.
[0011]
The controller 21 controls the operation of the heat pump cycle based on the amount of heat collected by the solar heat collector 1, and at the same time, adjusts the hot water mixing three-way valve 18 at the junction of the bypass pipe 16 branched from the water supply pipe 15 and the hot water storage tank outlet pipe 17. Then, the temperature of the mixed hot water is adjusted, and hot water is supplied to a desired hot water supply temperature.
[0012]
Here, the condenser (high-temperature side heat exchanger) 13 of the heat pump cycle system uses a hot water storage tank internal heat exchange system, but may use an external heat exchange system arranged outside the hot water storage tank 2. At that time, in order to exchange heat with the water in the hot water storage tank 2, the water in the hot water storage tank 2 is withdrawn from the lower part of the hot water storage tank 2, and the water is circulated to the condenser (high-temperature side heat exchanger) 13 via the circulation pump 4. Then, the hot water can be returned to the upper portion of the hot water storage tank 2.
[0013]
In addition, examples of the material of the heat exchanger, piping, hot water storage tank, and the like used in the present invention include metals such as stainless steel, aluminum, aluminum alloy, copper, copper alloy, and steel. It is appropriately selected depending on the refrigerant and heat medium used. Depending on the operating temperature and pressure, plastics such as polyethylene, polypropylene, polybutene, and vinyl chloride can also be used.
[0014]
The heat pump includes a piston type, a rotary type, a scroll type, a screw type, a centrifugal type, and the like, depending on the type of the compressor, and any of them can be used. In addition, refrigerants include natural refrigerants such as carbon dioxide and ammonia, in addition to CFCs (chlorofluorocarbons), HCFCs (hydrochlorofluorocarbons), HFCs (hydrofluorocarbons), and the like. .
Various hot water pumps can be used as the circulation pump. Considering the maintenance, a sealless pump of a magnet type or the like is preferable.
[0015]
FIG. 2 shows another example of a hot water heater, which uses a stationary polymer fuel cell for home use. On the fuel cell side, as shown, a reformer 8 for obtaining hydrogen (fuel for the fuel cell) from city gas, a blower 19 for supplying oxygen in the air, and a polymer electrolyte fuel cell ( A battery section 9 and an evaporator (low-temperature side heat exchanger) 11 for pumping exhaust heat from the reformer 8 and the battery section 9 are provided to forcibly circulate a heat medium in a circulation path. And
a) Pumping (low-quality) exhaust heat generated on the fuel cell side by using a refrigerant in an evaporator (low-temperature side heat exchanger) 11 (gasification of the refrigerant);
Then,
b) The refrigerant gas is pressurized and heated by a compressor (usually operated by a commercial power supply) 12;
c) Pump up heat in a condenser (high-temperature side heat exchanger) 13 provided on the hot water storage tank side (liquefy refrigerant gas);
d) expanding the liquefied refrigerant with an expansion valve 14;
With the heat pump constituting the above heat pump cycle, the hot water in the hot water storage tank is heated in the condenser (high temperature side heat exchanger) 13 by the sensible heat of the refrigerant gas and the latent heat of condensation by the electric energy from the commercial power supply.
[0016]
The controller 21 controls the operation of the polymer electrolyte fuel cell (cell unit) 9 and the operation of the heat pump, and controls the heat pump operation according to the amount of heat discharged from the polymer electrolyte fuel cell (cell unit) 9. . In addition, the temperature of the hot water in the hot water storage tank 2 is constantly monitored to secure an appropriate amount of hot water and the hot water temperature, and the hot water temperature set by the remote controller 20 (the desired hot water temperature or a temperature higher by 1 to 2 ° C. than that). The opening degree of the hot / water mixing three-way valve 18 between the hot water in the hot water storage tank 2 and the water from the water supply source is adjusted so as to be able to perform the above operations.
[0017]
The fuel cell will be described. The supplied city gas is introduced into the reformer 8 and reformed into hydrogen (one of the fuels of the polymer electrolyte fuel cell), and together with the oxygen (in the air) from the blower 19, the solid polymer fuel is It is guided by a battery (battery unit) 9 to generate power. At this time, waste heat is generated from the polymer electrolyte fuel cell (cell part) 9, and the waste heat is introduced into the evaporator 11 of the heat pump cycle and used.
[0018]
When a polymer electrolyte fuel cell having a power generation capacity and a waste heat amount of 1 kW each is operated continuously for 24 hours, only the latter waste heat amount becomes 3600 kJ / h, and the waste heat amount is 300 L of water in the tank (300 L). Capable of increasing the temperature by 69 ° C. (3600 × 24 × 300 ÷ 4.2). However, since the optimum temperature for operating the polymer electrolyte fuel cell is about 70 ° C., the temperature of the hot water stored in the hot water storage tank 2 is about 60 ° C. at most (about 10 ° C. lower than the above temperature). The level is not a satisfactory temperature. It is conceivable to further increase the capacity of the hot water storage tank to sufficiently meet demand, but this is not a good method. In order to store hot water at a higher temperature, a separate heating means is required.
[0019]
Therefore, as shown in FIG. 2, a heat pump cycle is added to the exhaust heat recovery unit. Depending on the operating conditions, the temperature of the hot water in the hot water storage tank 2 can be increased to about 90 ° C., and can be pumped from a heat source with a higher temperature than when the heat is directly pumped from atmospheric heat with a heat pump. The efficiency of the heat pump cycle can be increased.
[0020]
At the time of hot water supply, since the hot water temperature in the hot water storage tank 2 is high, the hot water mixing three-way valve 18 at the junction of the hot water storage tank outlet pipe 17 and the bypass pipe 16 is merely adjusted to obtain the desired hot water supply temperature. Can supply hot water.
[0021]
Although the example in FIG. 2 is an example of a polymer electrolyte fuel cell, a solar cell may be used instead. Further, a hybrid system of a solar cell and a solar water heater may be used.
[0022]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the hot-water storage water heater which concerns on this invention, a hot-water storage water heater which can supply hot water at a desired hot-water supply temperature can be provided, without using an auxiliary heat source like an instantaneous water heater. In other words, even if the temperature of the hot water in the hot water storage tank is in the range of about 30 to 40 ° C., which is lower than the desired hot water supply temperature, the hot water is supplied at the desired hot water supply temperature without being diluted with water and temporarily lowered to about 30 ° C. There is no waste of energy. In addition, the amount of carbon dioxide generated can be reduced and it is environmentally friendly. In addition, since additional heating by the auxiliary heat source is not required, the structure and system for temperature control are simplified.
[Brief description of the drawings]
FIG. 1 is an example of a hot-water storage / hot-water supply device of the present invention (using a solar heat collector).
FIG. 2 is a hot-water storage / hot-water heater of another example of the present invention (using a fuel cell).
FIG. 3 shows a conventional (solar heat type) hot water supply / hot water supply device.
[Explanation of symbols]
1: Solar heat collector 2: Hot water storage tank 3a: Outgoing pipe 3b: Return pipe 4: Circulation pump 5: Buffer tank 6: Heat exchanger 7: Auxiliary heat source (flash water heater)
8: Reforming section (reformer) 9: Battery section 11: Evaporator (low-temperature side heat exchanger) 12: Compressor 13: Condenser (high-temperature side heat exchanger) 14: Expansion valve 15: Water supply pipe 16: Bypass pipe 17: Hot water storage tank outlet side pipe 18: Hot water mixing three-way valve 19: Blower 20: Remote control 21: Controller 30: Hot water storage water heater (solar heat type)
40: Hot water storage water heater (using fuel cell)
HP: Heat pump (heat pump cycle)

Claims (3)

A solar water collector and a hot water storage tank are hot water storage water heaters connected via a heat exchange system,
The heat exchange system is a hot-water storage water heater provided with the following heat pumps a) to d).
a) pumping up the heat collected by the solar heat collector using a refrigerant in an evaporator (gasification of the refrigerant);
b) raising and raising the temperature of the refrigerant gas by a compressor;
c) Pumping heat with a condenser provided on the hot water storage tank side (liquefaction of refrigerant gas);
d) The liquefied refrigerant is expanded by an expansion valve. A heat generating unit and a hot water storage tank are hot water storage water heaters connected via a heat exchange system,
The heat exchange system is a hot-water storage water heater provided with the following heat pumps a) to d).
a) pumping up the heat generated in the heat generating section using a refrigerant in an evaporator (gasification of the refrigerant);
b) raising and raising the temperature of the refrigerant gas by a compressor;
c) Pumping heat with a condenser provided on the hot water storage tank side (liquefaction of refrigerant gas);
d) The liquefied refrigerant is expanded by an expansion valve. The hot-water storage water heater according to claim 2, wherein the heat generation unit is a waste heat recovery unit of a battery unit or a reforming unit of the fuel cell, or a solar cell.

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