JP3242143B2 - Ammonia refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ammonia refrigerator using an ammonia refrigerant.

[0002]

2. Description of the Related Art Generally, in buildings where many people live, such as buildings, hotels, hospitals, etc., it is essential to provide hot water supply equipment together with cooling equipment. In particular, supplying hot water to a kitchen, a washroom, a washing place, or the like can improve the work efficiency more cleanly and can be said to be an important facility indispensable to sanitary facilities.

[0003] Such a hot water supply system for a building includes a local type in which hot water is individually supplied to a place where hot water is used by a small heater or the like, and a large heating device provided in a machine room of the building, and a pipe provided at a required location. There is a central type for hot water supply, and the central type is adopted when hot water supply points and hot water supply amount are large in hotels, hospitals, factories, offices, and the like. In the central type, steam, gas, kerosene, or the like is used as a heat source, and the temperature of supplied hot water is generally 60 to 70 ° C., which is higher than the temperature usually used.

[0004] On the other hand, such a building is cooled by providing a large refrigerator in a machine room of the building. As such a refrigerator, a refrigerator using a CFC-based refrigerant is mainly used. This is because the CFC-based refrigerant is considered to have a high effect as a refrigerant and to be extremely safe.

[0005]

However, in recent years,
Energy saving is required in order to prevent global warming and air pollution, and equipment for energy saving is also required for cooling and hot water supply inside buildings.

[0006] In recent years, it has been found that ozone is decomposed by chlorofluorocarbon, which has become a serious problem for the global environment. In other words, when CFCs are released into the atmosphere from refrigerators, etc., they rise in the atmosphere and reach the ozone layer that is formed so as to enclose the earth, where they decompose ozone, a component of the ozone layer. become. Therefore, there is a risk that the ozone layer will disappear if Freon continues to be released, and a large amount of harmful rays such as ultraviolet rays, which are conventionally blocked by the ozone layer, will reach the earth. It was also found that CFCs, together with carbon dioxide, cause global warming. This will have a serious effect on ecosystems and the like, and may also destroy the global environment. For this reason, in the near future, the production of all types of CFC-based refrigerants may be stopped.

[0007] Therefore, a conventionally used CFC-based refrigerant is replaced with a non-CFC-based refrigerant that does not affect the global environment. At present, use of ammonia has been proposed as the non-CFC-based refrigerant.

However, a refrigerator using an ammonia refrigerant has the following problems. That is, when ammonia is compressed by the compressor, the temperature of the ammonia becomes significantly higher than that of the chlorofluorocarbon-based refrigerant due to its thermodynamic properties, resulting in a significantly overheated state. The gas refrigerant discharged from the compressor is introduced into the condenser in such a high temperature / superheat state. Since the condenser of a conventional CFC-based refrigerant refrigerator introduces a relatively low-temperature gas refrigerant and liquefies it,
When a high-temperature gas refrigerant is introduced into such a condenser, the temperature cannot be sufficiently lowered, and it becomes difficult to completely liquefy the introduced gas refrigerant. In order to reliably liquefy high-temperature gaseous refrigerant in the condenser, it is necessary to increase the capacity of the condenser in response to the overheated condition and supply a large amount of cooling water or cooling air. No. However, this consumes a large amount of energy, which is contrary to energy saving currently being generally promoted.

The present invention has been proposed in order to solve the above-mentioned problems of the prior art. It is an object of the present invention to use an ammonia refrigerant which does not affect the global environment as a refrigerant, It is an object of the present invention to provide a high-performance ammonia refrigerator having a high energy saving effect capable of supplying hot water without using a hot water supply facility at the same time.

[0010]

In order to solve the above-mentioned problems, the following means is taken in the ammonia refrigerator of the present invention.

That is, in a refrigerator provided with a compressor, a condenser, and an evaporator for using a CFC-based refrigerant, ammonia is used as a refrigerant of the refrigerator, and between the compressor and the condenser, A hot water heat exchanger is connected as means for lowering the temperature of high-temperature ammonia gas discharged from the compressor, and the hot water heat exchanger is connected to hot water supply means.

[0012]

The operation of the ammonia refrigerator of the present invention having the above-described structure is as follows.

That is, a conventional chlorofluorocarbon-based refrigerant refrigerator is used.
Oite, hot water heat exchanger is connected is between the compressor and the condenser
Impact on the global environment as a refrigerant
The use of ammonia refrigerant without
Since the temperature at which the gas is introduced into the
As a result, the size of the condenser can be further reduced. On the other hand, hot water obtained by the hot water heat exchanger is supplied to a building or the like via hot water supply means such as a hot water supply pipe, so that hot water supply equipment becomes unnecessary.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the ammonia refrigerator of the present invention will be described below with reference to the drawings. Here, FIG. 1 shows an example of a circuit of the ammonia refrigerator of the present embodiment, and FIG. 2 shows a ph diagram of the ammonia refrigerator.

As shown in FIG. 1, the ammonia refrigerator includes a compressor 1, a condenser 2, and an evaporator 3, a hot water heat exchanger 4 is provided between the compressor 1 and the condenser 2, and a refrigerant pipe 5 is provided. To form a refrigeration circuit. The compressor 1 is driven by the electric motor 5 so that the gas refrigerant is subjected to polytropic compression. The condenser 2 is configured so that the gas refrigerant exchanges heat with the cooling water to become a liquid refrigerant, and the evaporator 3 is configured so that the liquid refrigerant exchanges heat with the cold water to form a gas refrigerant. Further, the hot water heat exchanger 4 is configured so that supply water at about 15 ° C. is supplied, and heat is exchanged between the supply water and the compressed gas refrigerant.

FIG. 2 shows a ph diagram (Mollier diagram) of the above-described ammonia refrigerator. In this figure, the vertical axis indicates the absolute pressure p [kg / cm2] of the refrigerant, the horizontal axis indicates the enthalpy h [kcal / kg] of the refrigerant, and a line representing the state of the ammonia refrigerant is shown therein. In other words, the right half of the vertex K (critical point) of the substantially U-shaped curve that opens downward is a saturated steam line, and the right side of this line is a superheated steam region, and the temperature becomes higher toward the right. On the other hand, the left half is the saturated liquid line, and the left side is the supercooled liquid region. Between the two curves is a state in which the liquid and the vapor coexist in the saturated vapor region. In this ph diagram, the temperature between A and D is about 0 ° C., and the point B 1 is about 120 ° C.
℃, B2 point is about 70 ℃, between B3-C is 40 ℃. AB-1 is a polytrope compression line.

In the refrigerator configured as described above, the ammonia refrigerant in the gas state at the point A in the ph diagram of FIG.
And is subjected to polytropic compression by the drive of the electric motor 6. At this time, the refrigerant is compressed through the polytropic compression line AB1 and discharged as a high-temperature gas refrigerant at about 120 ° C. The state of the ammonia refrigerant at this time is a point B1 in the ph diagram. That is, it is in a state where it is overheated by about 80 ° C. as compared with the saturated steam of the same pressure. The gas refrigerant is discharged to the refrigerant pipe in a high temperature state and sent to the hot water heat exchanger. In the hot water heat exchanger, the high-temperature gas refrigerant exchanges heat with the supply water at about 15 ° C., and is cooled to about 70 ° C. At this time, the state of the ammonia refrigerant is at a point B2 in the ph diagram, and is about 30 points.
It becomes overheated state of ° C.

The gas refrigerant cooled to about 70 ° C. is sent to the condenser 2, where the heat of the superheated portion of the ph diagram B 2 -B 3 is removed by the cooling water, and the saturated vapor temperature of the same pressure is obtained. Cool to 40 ° C. Further, condensation is performed from the saturated vapor state at the point B3 in the ph diagram to the point C, and the liquid is completely liquefied. The refrigerant discharged to the refrigerant pipe in the liquid state at the point C is rapidly expanded by an expansion valve (not shown) to have a low pressure and low temperature, and the evaporator 3 at the point D of isenthalpy in the ph diagram. Supplied to In the evaporator 3, heat exchange is performed with cold water or brine of an air conditioner or the like, and evaporates at a low temperature to become a gas refrigerant, which is sucked into the compressor 1. In this way, it works as a refrigeration circuit.

The supply water that has exchanged heat with the ammonia gas refrigerant in the hot water heat exchanger becomes hot water of about 60 ° C. and is supplied to a building or the like by hot water supply means.

As described above, in the ammonia refrigerator of the present embodiment, since the hot water heat exchanger is provided, about 120
At a high temperature of 80 ° C and about 80% higher than saturated steam at the same pressure.
By cooling the ammonia refrigerant that is overheated to about 70 ° C. to about 70 ° C., a superheated state of about 30 ° C. can be achieved. Here, a common chlorofluorocarbon-based refrigerant used in a refrigerator has a temperature at the point B1 of about 60 ° C., a temperature between B 3 and C of 30 ° C., and is in an overheated state of 30 ° C. Thereby, the refrigerant cooled by the hot water heat exchanger 4 provided in the present embodiment sufficiently removes the heat of the superheated portion B2-B3 even when using the condenser of the conventional CFC-based refrigerant refrigerator. Can be condensed.

Therefore, the ammonia refrigerant that does not affect the global environment can be sufficiently condensed by the small condenser, and a high-performance refrigerator with high energy saving effect can be obtained. In addition, at the same time as the cooling of the building is performed as in the past, the hot water obtained by the hot water heat exchanger can be supplied to the building by the hot water supply means. It is possible to drastically reduce the power consumption, and it is possible to further save energy.

The ammonia refrigerator of the present invention is not limited to the embodiment described above. For example, the refrigeration circuit is not limited to the circuit shown in FIG. 1 and can be appropriately changed, such as a circuit using a liquid receiver or the like. Further, by changing the efficiency of the hot water heat exchanger and reducing the superheat temperature of the refrigerant supplied to the condenser, it is possible to obtain a condenser that is smaller than before. Further, the supply temperature of hot water can be changed by appropriately changing the efficiency of the hot water heat exchanger.

[0023]

According to the present invention, an ammonia refrigerant which does not affect the global environment can be used as a refrigerant in a safe state, and energy can be saved by reducing the size of the condenser of the refrigerator. A high-performance ammonia refrigerator can be provided. In addition, since hot water can be supplied to the building at the same time as cooling without using hot water supply equipment, it is possible to significantly save energy.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of an ammonia refrigerator of the present invention.

FIG. 2 is a ph diagram of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Compressor 2 ... Condenser 3 ... Evaporator 4 ... Hot water heat exchanger 5 ... Refrigerant piping 6 ... Electric motor

Continuation of the front page (56) References JP-A-60-245961 (JP, A) JP-A-62-112970 (JP, A) JP-A-3-67966 (JP, U) JP-A 34-17980 (JP) , Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 1/00 F25B 29/00

Claims (1)

(57) [Claims] 1. A refrigerator including a compressor, a condenser, and an evaporator for using a CFC-based refrigerant, wherein ammonia is used as a refrigerant of the refrigerator, and between the compressor and the condenser. A hot water heat exchanger is connected as means for lowering the temperature of the high-temperature ammonia gas discharged from the compressor, and the hot water heat exchanger is connected to hot water supply means.