JPH0585816B2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention is directed to cold storage and
The present invention relates to a heating and cooling method that uses latent heat to reduce heating and cooling costs by using a heat storage source as thermal energy for daytime heating and cooling operations.

``Conventional technology'' The use of nighttime electricity for cooling during the summer is particularly encouraged as it helps level out the electricity load. The latent heat of ice is stored in a cold storage tank such as an ice bank, and during daytime cooling operation,
Instead of directly placing the cooling load on the refrigerator, cooling is performed mainly using the latent heat of the ice.On the other hand, during winter heating, the refrigerator operates as a heat pump, producing hot water using nighttime electricity, which is stored in a large heat storage tank installed underground. 2. Description of the Related Art A so-called late-night power-using type air-conditioning/heating system that stores heat in a heat storage tank and performs daytime heating operation using the thermal energy in the heat storage tank is known.

``Problem to be solved by the invention'' However, unlike the heat storage tank used for summer cooling, the heat storage tank used for winter heating uses sensible heat, so it requires a considerably larger volume than the heat storage tank, and has a higher strength. In addition, since it is installed underground and isolated from mechanical equipment for heat retention, not only does the construction cost for installing an underground tank increase, but also the piping work cost to connect the compressor and other mechanical equipment. It costs extra.

In addition, in the case of heating and cooling buildings, the mechanical equipment is generally placed on the rooftop, but if such a configuration is adopted, pump power for hot water is required, and operating costs are also increased.

Also, if the mechanical equipment is placed below, the refrigerant piping becomes complicated and efficiency is not good.

On the other hand, if the cold storage tank could be used also as a heat storage tank in the winter, the above disadvantages would be solved, but the melting point of the cold storage tank is 0°C, and the temperature range in which it is used as hot water heat storage for winter heating is different, and the amount of heat is Due to the lack of water, it is impossible to use both, and a heat storage tank capable of storing hot water heat for winter heating is required separately from the cold storage tank.

Also, in order to eliminate the above-mentioned drawbacks, it is possible to use both the cold storage tank and hot water storage, but with this configuration, the power and capacity of the refrigerator must be overestimated by that amount, After all, installation costs and operating costs will be high.

For this reason, a heating and cooling system that uses cold storage and heat storage sources obtained using nighttime electricity as thermal energy for heating and cooling operations during the day is advantageous from the standpoint of both heating and cooling costs and leveling out electricity usage. Despite meeting social demands, there has been little progress in converting from heating and cooling systems that operate only during the day.

Next, for reference, let's examine the problem of heating and cooling systems that perform cooling and heating operations only during the day from the perspective of compression efficiency.Heating operation using a heat pump during winter heating requires an outside air heat source whose evaporation temperature is below minus, for example, outside air during winter. If the temperature is -5℃, it becomes the evaporation temperature of the heat pump system (-10℃), and since the heating water temperature needs to be 50℃, the condensation temperature (55℃)
The difference between the two is Δt65℃, which requires a high compression ratio. On the other hand, during summer cooling, the evaporation temperature of the cooling system is -5°C and the air cooling condensation temperature is 40°C, and the difference between them is Δt45°C, so the compression ratio is smaller than during winter heating.

Therefore, when comparing the power when a single-stage compressor is used in the above-mentioned heating and cooling system, under the above conditions, the heating power is more than 20% larger than the cooling power, so the power of the refrigerator is equal to the maximum compression ratio of the heat pump. As a result, the power factor of the compressor during cooling decreases, resulting in an extra yearly contract, resulting in additional electricity costs, and an increase in power consumption due to unbalanced compression ratios. There is also a risk of overpowering due to imbalance.

The present invention eliminates the drawbacks of the prior art, reduces costs by using late-night electricity, and uses latent heat for both cooling and heating, thereby reducing the size of the entire system. The objective is to provide a heating and cooling system that increases volume and significantly reduces construction costs. Another object of the present invention is to integrate the cold storage tank and the heat storage tank so that they can be used for both cold storage during cooling and heat storage during heating. The above-mentioned integrated cold storage/thermal tank can be installed as a unit or package on the rooftop, etc., resulting in further reduction in volume, reduction in piping construction costs, and reduction in pump power and other operating costs. The purpose of the present invention is to provide a highly efficient heating and cooling system.

"Means for Solving Problems" In order to achieve the above technical problem, the present invention provides a heating and cooling method that utilizes a cold storage/heat storage source obtained using nighttime electricity as thermal energy for heating and cooling operation during the day. , using a heat pump device comprising a heat storage tank that stores a plurality of latent heats including latent heat of ice and latent heat around room temperature of 10 to 30°C, and a single-stage compressor that compresses the refrigerant heat exchanged by the heat storage tank, During summer cooling, an outside air heat source of around 15 to 30°C is taken in at night, and the single-stage compressor operates in a refrigeration cycle to store ice latent heat in the heat storage tank. Cooling operation is performed by circulating fresh water or brine using the ice latent heat stored in the tank, while during winter heating, the heat pump cycle operation of the single-stage compressor uses the outside air heat source as evaporation heat at night. After performing substantial low-stage compression in which the heat source at an intermediate temperature of 15 to 30°C is stored as latent heat in the cold storage heat storage tank, the latent heat stored at the intermediate temperature during the daytime is then converted into heat of evaporation to perform the single-stage compression. The heat pump cycle operation of the machine essentially performs high-stage compression to approximately 40 to 60℃.
We propose a heating and cooling method characterized by obtaining front and rear heating loads and effectively utilizing the temperature difference between night and day to perform staggered two-stage compression operation using a single-stage compressor.

In this case, the ice latent heat used during winter heating is stored in a cold storage tank, etc., which stores the latent heat of ice.
By filling a latent heat storage agent with a melting point near room temperature, such as a latent heat storage agent encapsulated in a resin capsule, which is used during winter heating, cold storage and
Thermal baths will be shared.

The cold storage tank may be constructed by mixing or stacking capsules filled with a latent heat storage agent having a melting point near room temperature and capsules filled with fresh water. In this case, an antifreeze solution is provided between the cold storage tank and the chiller. It is preferable to configure it so that it circulates.

Furthermore, it is also possible to use a solar water heater to store thermal energy during winter heating, and it is also possible to configure the cold storage heat tank and the solar water heater to communicate with each other.

"Operation" According to this invention, especially during winter heating, heat pump operation using outside air as a heat source can be performed at temperatures of 15 to 30 degrees Celsius.
In order to store heat as latent heat near room temperature, the two-stage compressor operates on the low-stage compression mode, and during the day, this heat storage is used as a heat source for the high-stage compressor to heat water used for space heating up to a temperature of 50°C. Since there is a time difference between the two stages of compression, it is possible to substantially reduce the compression efficiency and power cost. By using the compressor twice, even a single-stage compressor can perform two-stage compression operation, making it possible to downsize the device.

Further, according to the present invention, since latent heat can be utilized in both winter and summer, it is possible to significantly downsize the heat storage tank especially during winter heating compared to the conventional technology. By filling the cold storage tank used for cooling with a latent heat storage agent with a melting point near room temperature, it becomes possible to perform heating and cooling using the nighttime electricity with a single cold storage tank, resulting in miniaturization. Even if a single cold storage heat tank is installed on the roof of a building together with mechanical equipment such as the compressor, there will be no problem in building strength, significantly reducing construction costs, eliminating the need for pump power for pumping water, Piping can be simplified, and operating costs and maintenance costs can be significantly reduced.

That is, the present invention effectively utilizes the temperature difference between night and daytime and the heat storage tank during winter heating to perform substantial two-stage compression using a single-stage compressor. The compressor itself can reduce power consumption compared to a two-stage compressor, and on the other hand, by performing single-stage compression operation at night during summer heating, in other words, one can perform two-stage compression and the other can perform single-stage compression. By doing this, it is possible to eliminate the load balance between summer cooling (essentially one-stage compression due to the low compression ratio).

In addition, during summer cooling, latent heat is stored for cooling from low temperatures at night, rather than from high temperatures during the day, which not only reduces the cost of electricity at night but also reduces the operating power itself. , leading to double savings.

"Embodiments" Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in this example are as follows, unless otherwise specified.
This is not intended to limit the scope of the invention, but is merely an illustrative example.

FIG. 3 shows a cold storage heat tank 5 used in the present invention. As is well known, a coiled tube 7 which functions as an evaporator and a condenser is rotatably arranged in the tank 5 in a hairpin shape. 5, a spray part 25 is disposed on top of the spray part 25.

Also, inside the tank 5 is a spherical ball 29 with a diameter of approximately 30 to 80 mm.
The inside of the ball 29 has a melting point of 20
~22℃, with a latent heat of fusion of 35-37Kcal/ ^cm2
A latent heat storage material such as CaCl ₂ .6H ₂ O is enclosed.

Incidentally, the CaCl ₂ 6H ₂ O may be used alone,
Also, by mixing a catalyst, the melting point is 20~22℃, 25~26℃, 28℃.
The spherical balls 29 formed to have a temperature of 29° C. and filled with such a latent heat agent may be sequentially stacked and arranged in three stages. In this case, the spray section 25
The structure is such that clear water is sprayed to form ice on the outer surface of the coiled pipe 7. As a result, by adding a low melting point catalyst or a high melting point catalyst to the above in a predetermined ratio, the latent heat temperature can be freely set within the range of 10 to 30°C.

(First Example) In addition, the spherical ball 29 is filled with fresh water sealed and _a latent heat agent of CaCl ₂ . In this case, the spray part 2
5 to spray antifreeze. (Second Embodiment) In addition to the spherical balls 29, the capsules filled in the heat storage tank may be cylindrical or other shaped capsules made of resin or metal with good thermal conductivity.

FIG. 1 shows an embodiment of the present invention using such a cold storage heat tank 5. First, the circulation path of fresh water or brine will be explained. 21 is a circulation pump that circulates brine made of fresh water or antifreeze, and 4 is a heat exchanger. After being primarily cooled by the chiller 4 through a piping 20 connected to the load, a three-way switching valve 27, and a return pipe 23, it returns to the cold storage heat tank 5 via a three-way switching valve 28 and piping 24. , constitutes a circulation path during nighttime operation (low stage compression operation) during summer cooling and winter heating.

On the other hand, during daytime operation (high-stage compression operation) during winter heating, the pump 22 and the bypass pipe 2
6, a circulation path passing through the cold storage heat tank 5 and a circulation path passing through the chiller 4 are formed separately, and the cold storage heat tank 5
The coil tube 7 functions as an evaporator on the side, and the coil tube 7 functions as a condenser on the chiller 4 side.

In addition, 50 is a solar water heater, which is connected to the spray part 25 by branching the piping 20 on the outlet side of the circulation pump 21, and when heating fresh water or brine in winter, the fresh water or brine is used together with the compressor 1 in the solar water heater. 50
The compressor 1 is heated to reduce the load on the compressor 1 and the power cost.

Next, to explain the refrigerant circulation system, 1 is a compressor, 2
is an outside air heat source condenser and evaporator with a built-in heat exchanger 3, a four-way switching valve 17, a three-way switching valve 18,
19 and expansion valves 8, 8-1, and 8-2, it is connected to the coil tube 7 of the cold storage heat tank 5 and the heat exchanger 6 in the chiller 4 via piping 9 to 16, and the four-way switching valve 17 By appropriately switching the three-way switching valves 18 and 19, a predetermined refrigerant circulation path, which will be described later, is constructed.

The effects based on this configuration will be explained separately for summer cooling and winter heating.

A During summer cooling A-1 Thermal energy storage at night First, the fresh water or brine circulation path of the cold storage heat tank 5 is bypassed by the pump 21 and the bypass pipe 22, and a refrigeration cycle is configured on the refrigerant side.
Ice latent heat is stored in the cold storage heat tank 5.

That is, in the first embodiment, the fresh water circulating in the closed circuit that does not pass through the load side through the bypass pipe 22 is first cooled by the heat exchanger 6 (evaporator) in the chiller 4 to a primary chiller temperature of 0°C or higher, and then passed through the pipe 24. The water sprayed from the spray section 25 in the cold storage heat tank 5 cools the coiled tube 7 (evaporator) secondarily by soaking it in the water, and freezes on the outer surface of the coiled tube 7 at a temperature below the freezing point. In this case, the heat storage agent 29 in the capsule
CaCl ₂ 6H ₂ O is in a solidified state and has no sensible heat.
It will be kept cold below ℃.

On the other hand, the heat-absorbed refrigerant in the coiled pipe 7 is transferred to the pipe 1
After being compressed by the compressor 1 through the three-way switching valve 18, the four-way switching valve 17, and the three-way switching valve 19,
After entering the heat exchanger 3 of the outside air heat source type condenser/evaporator 2 and being condensed there, the heat is exchanged between the coil tube 7 in the cold storage heat tank 5 and the chiller 4 via the expansion valve 8 8-2. The fresh water is evaporated in a vessel 6 and cooled. After this, repeat this to cool the ice latent heat and spherical ball 2.
9. Perform sensible heat and cold storage.

In addition, since the outside air temperature at night is lower than the outside air temperature during the day, the electricity cost for the cold storage is low because late-night electricity is used, which requires a lower compression ratio than daytime cooling and is also cheaper.

Further, in the case of the second embodiment, not the antifreeze itself sprayed from the spray section 25 but the fresh water sealed in the spherical ball 29 is stored as ice latent heat.

A-2 Cooling operation during the day During the day, the three-way switching valve 27 is switched to the load side, and the circulation pump 21 operates between the cold storage heat tank 5, the load, and the chiller 4.
The compressor 1 is configured so that fresh water or brine is circulated between the compressors 1 and 1, and the compressor 1 is stopped during the day.

By operating the circulation pump 21,
The fresh water used for cooling on the load side passes through the chiller 4 from the return pipe 23 and is sprayed directly from the upper part of the cold storage heat tank 5, where the latent heat of ice, cold water, and spherical balls 29
The sensible heat of the air conditioner is repeatedly cooled by the cold storage agent that is stored during the night, and a predetermined cooling operation is performed.

In this case, the daytime operation of the compressor 1 is stopped, which not only reduces power costs but also helps level out power by cutting cooling peaks in the summer.

Alternatively, the compressor 1 may not be stopped and only the heat exchanger 6 of the chiller 4 may be operated for cooling.

That is, the fresh water or brine cooled in the cold storage heat tank 5 is cooled on the load side, and then primarily cooled by the chiller 4 and then transferred to the three-way switching valve 28 and the piping 2.
4, it returns to the cold storage heat tank 5, where it is subjected to secondary cooling by the latent heat of ice formed in the coiled tube 7, and this process is repeated thereafter to perform cooling operation.

Therefore, even in such a case, during daytime cooling, frozen water (coiled pipe 7
In order to perform secondary cooling using the ice latent heat of the surface or inside the spherical ball 29, the refrigeration cycle on the compressor 1 side only needs to be cooled by the chiller 4;
Because primary cooling is performed at temperatures above 0°C, a low compression ratio is sufficient, and power costs can be significantly reduced.

B During winter heating B-1 Thermal energy storage at night On the other hand, in heating operation during winter heating, the compressor 1 is operated at night by heat pump operation, and the heat exchanger 3 (evaporator) of the evaporator and condenser 2 is used as an outside air heat source. After the heat-absorbed refrigerant is compressed by the compressor 1,
It is introduced into the coiled tube 7 and the heat exchanger 6 through the piping 14 and 15 through the dotted line of the four-way switching valve 17, and then the piping 20
The heat of condensation is released by fresh water or antifreeze circulating in ~24.

Then, the fresh water or antifreeze heated by the heat of condensation is sprayed from the spray section 25, thereby removing the _CaCl2 .
Thermal energy is stored in 6H ₂ O at the condensation temperature on the lower stage compression side in the two-stage compression, that is, at the intermediate temperature, in the normal temperature range including the latent heat and sensible heat of about 20 to 30°C.

B-2 Daytime Heating Operation During the day, the three-way switching valve 27 is switched to the load side, and the coiled pipe 7 of the cold storage heat tank 5 is used as an evaporator, and the heat exchanger 6 on the chiller 4 side is used as a condenser, and the three-way switching valve 27 is switched to the load side. The switching valve 28 is switched, and a circulation path passing through the cold storage heat tank 5 and a circulation path passing through the chiller 4 are respectively formed by the pump 21 and the bypass pipe 26.

With the above configuration, thermal energy containing latent heat and sensible heat of around 20 to 30 degrees Celsius stored during the nighttime operation is used as a heat source, and fresh water or antifreeze in the circulation path that circulates with the heating load on the chiller 4 side is used for heating. A heat pump cycle that heats the room to the required temperature of around 50℃ is configured, and heating operation is possible through compression operation with a low pressure ratio.Therefore, it becomes a two-stage compression operation with a time difference that efficiently utilizes late-night electricity, where electricity costs are low. This greatly reduces daytime power consumption, enables power leveling, and reduces overall power costs.

FIG. 2 shows another embodiment using a two-stage compressor.

The two-stage compressor includes a low-stage compressor 1-1 and a high-stage compressor 1-2, and the discharge pipe 33 on the low-stage compressor 1-1 side is connected to the coil pipe 7 in the cold storage heat tank 5. On the other hand, the outlet side of the coiled pipe 7 branches and communicates with the suction pipe 14 on the high-stage compressor 1-2 side and the heat exchanger in the chiller 4 via the expansion valve 8-2. ing. Further, the discharge pipe 9 on the high-stage compressor 1-2 side communicates with the other end of the heat exchanger 6 in the chiller 4.

In this embodiment, the same effects as in the first embodiment can be obtained, but the high-stage compressor 1, which has a small piston displacement during daytime operation during winter heating,
Compression efficiency and power balance are further improved because the engine is operated using

FIG. 4 shows a comparative example of the present invention, which has almost the same configuration as the embodiment shown in FIG. 1, so the explanation will focus on the differences from FIG. 1. The spherical balls 29' filled in the heat storage tank 5' are filled with a heat storage agent whose main component is paraffin and whose melting point is set at around 55°C. Use a compressor.

In this embodiment, during summer cooling, thermal energy storage during the night and cooling operation during the day are carried out in exactly the same manner as in the first embodiment.

On the other hand, during winter heating, the refrigerant that has been absorbed by the heat exchanger 3 (evaporator) of the evaporator/condenser 2 by the outside air heat source is transferred to the compressor 1 by the heat pump operation of the thermal energy storage two-stage compressor at night. After being compressed in two stages, it is introduced into the coiled pipe 7 of the heat storage tank 5, and the condensation heat of around 60°C is sealed in the spherical ball 29' through fresh water or antifreeze that circulates in the pipes 20 to 24. Transferring heat to paraffin or other latent heat storage material to liquefy the paraffin;
It stores thermal energy including latent heat and sensible heat around 50-60℃.

During the daytime heating operation, the three-way switching valve 27 is switched to the load side during the day, and the circulation pump 21 is switched to the load side.
By configuring fresh water or brine to circulate through the cold storage heat tank 5, load, and chiller 4, and operating the circulation pump 21 with the two-stage compressor 1' stopped, the heat storage is performed using fresh water or antifreeze as a heat medium. Agent 2
Heating operation is performed by heat exchange between 9' and the heating load.

Therefore, in this embodiment, during winter heating as well as during summer cooling, the compressor is not used during the day, and only late-night power can be used, making it possible to use late-night power even further.

"Effects of the Invention" As described above, the present invention makes it possible to utilize latent heat in both winter and summer, making it possible to significantly downsize the heat storage tank, especially during winter heating, compared to the conventional technology. The tank can be installed on the roof instead of underground, which significantly reduces construction costs, eliminates the need for pump power for pumping water, and simplifies piping, resulting in a significant reduction in operating and maintenance costs.

Further, according to the present invention, it is also possible to integrate the cold storage tank used during summer cooling with the heat storage tank,
Further miniaturization is possible, and even if the single cold storage heat storage tank is installed on the roof of a building together with mechanical equipment such as the compressor, there will be no problem with building strength, and it can be easily installed in existing buildings. It is possible to modify the

Further, according to the present invention, since the heat storage tank has been miniaturized, it is easy to put into practical use an air-conditioning system that performs substantial two-stage compression operation through a time difference.
As a result, it has become possible to significantly reduce compression efficiency and power costs.

It has various effects such as

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a heating and cooling system according to an embodiment of the present invention, FIG. 2 is a schematic diagram of a heating and cooling system according to another embodiment, and FIG. 4 is a schematic diagram of a heating and cooling system according to a comparative example of the present invention. The schematic explanatory drawing, FIG. 3, is a schematic cross-sectional view of the cold storage heat tank used in each of the above embodiments.

Claims (1)

[Scope of Claims] 1. In a heating and cooling method that uses a cold storage/heat storage source obtained using nighttime electricity as thermal energy for heating and cooling operation during the day, there is Using a heat pump device equipped with a heat storage tank that stores latent heat and a single-stage compressor that compresses the refrigerant that is heat-exchanged by the heat storage tank, during summer cooling, an outside air heat source of around 15 to 30 degrees Celsius is used at night. After the latent heat of ice is stored in the heat storage tank by the refrigeration cycle operation of the single-stage compressor, the latent heat of ice stored in the cold storage tank is used to circulate fresh water or brine during daytime cooling. On the other hand, during winter heating, the outside air heat source is used as evaporative heat at night, and the single-stage compressor is operated in a heat pump cycle to transfer the heat source at an intermediate temperature of 15 to 30°C to the cold storage heat tank as latent heat. After performing substantial low-stage compression to store heat as heat, the latent heat stored at the intermediate temperature during the daytime is used as evaporation heat to substantially perform high-stage compression by heat pump cycle operation of the single-stage compressor. 40~60℃
A heating and cooling method characterized by obtaining front and rear heating loads, thereby effectively utilizing the temperature difference between night and day to perform staggered two-stage compression operation using a single-stage compressor.