JPH04146988A - Air conditioning apparatus for freezing and refrigeration - Google Patents

Abstract

PURPOSE:To reduce an adverse effect on the environment of the earth and to get rid of danger of ignition and explosion by using 1,1,2,2-tetrafluoroethane as a refrigerant. CONSTITUTION:A refrigerant comprising 1,1,2,2-tetrafluoroethane and containing, if necessary, 0.01-5wt.% stabilizer is used in an air conditioning apparatus for freezing and refrigeration for car coolers, electric refrigerators, show cases, room coolers, package air conditioners, freezing contains, water chillers, briner chillers, drinking water cooler, etc.

Description

[Detailed description of the invention] Industrial applications The present invention relates to freezing, refrigeration, and air conditioning equipment.

Conventional technologies and their problems Conventionally, as working fluids or refrigerants for freezing, refrigeration, and air conditioning equipment, chlorofluorocarbons, hydrofluorocarbons, hydrofluorocarphones, azeotropic mixtures thereof, and compositions in the vicinity thereof have been used. A mixture of is known. Of these, R is currently the working fluid for refrigerators.
-110lichlorofluoromethane), R, -22()1
hydrochlorodifluoromethane), R-114 (1,2
-dichloro-1,1,2,2-tetrafluoroethane)
etc. are mainly used. However, in recent years, certain chlorofluorocarbons and hydrochlorofluorocarbons containing chlorine and bromine have been shown to deplete the stratospheric ozone layer when released into the atmosphere, resulting in serious damage to the earth's ecosystems, including humans. It has been pointed out that it may have a negative impact. Therefore, the use and production of these chlorine-containing chlorofluorocarbons and hydrochlorofluorocarbons, which have a high possibility of ozone layer depletion, are restricted or are about to be restricted by international agreements. Specifically, among commonly used refrigerants, chlorofluorocarbons such as R-11, R-12, and R-114 are scheduled to be completely phased out by the year 2000, and refrigerants such as R-22 Regarding hydrochlorofluorocarbons, arrangements are also being made to limit or eliminate the use and production of hydrochlorofluorocarbons from 2015 to 2030.

Today's global problem of destruction of the human habitable environment is not just the destruction of the ozone layer, but also the problem of climate warming caused by carbon dioxide and other gases. Regarding climate warming, reducing electricity consumption will also suppress carbon dioxide emissions and slow the progress. Refrigeration and air conditioning equipment is widely used as indispensable equipment in today's modern society, but on the other hand,
The amount of electrical energy consumed by these devices is enormous, and it can be said that saving energy in refrigeration, refrigeration, and air conditioning equipment has become an urgent issue. In this way, refrigerants, which can be called the lifeblood of freezing, refrigeration, and air conditioning equipment, are not only directly involved in the destruction of the global environment, but also indirectly contribute to global environmental problems through the power consumption of the systems. The choice of refrigerant for the system has become extremely important. Under these circumstances, R-12
In the refrigeration, freezing, and air conditioning equipment industry involved in the manufacture of car coolers, electric refrigerators, showcases, room coolers, package near conditioners, etc. that use R-12 as a refrigerant, 1. 1.
1. 2-tetrafluoroethane (R-134a)
, 1,1-difluoroethane (R-152a), and monochlorodifluoromethane (R-22) are being considered. However, each of these has the following problems, and it is currently difficult to solve them.

First, R-134a is a hydrofluorocarbon that is nonflammable and has a saturated vapor pressure that is most similar to that of R-12, so it is seen as a favorite as an alternative refrigerant to R-12, and its adoption is being considered in various fields. has been done.

However, R134a has extremely poor compatibility with lubricating oils and its range is extremely limited, so there are many practical problems. Polyglycol oil is an oil that shows a high degree of compatibility with R-134a, but when this oil coexists with a refrigerant, the wear resistance of metal sliding parts is much better than when R-12 coexists with mineral oil. It is known that the dielectric strength of the terminals of built-in motors is not sufficient to meet the required performance. Therefore,
Research has also been conducted to try to solve these problems by adding additives to polyglycol oil. In addition, R-134a has a lower coefficient of performance than R-12, as shown in Tables 1 and 2 below.
This is also a disadvantage.

R-152a has a refrigeration cycle coefficient of performance of R-12.
, R-22, R-134a, etc., or lacks suitability as a refrigerant because it is a flammable gas. That is, as long as it is filled in the device, it will not burn, and if it leaks out of the device and mixes with the air, it will cause ignition and spread of fire, which is extremely dangerous. If such flammable gas is used in an electric refrigerator and scum leaks into the refrigerator or there is a fire in the surrounding area, there is a risk that it will catch fire and explode, causing a major accident. ing.

As mentioned above, R-22 contains chlorine atoms in its molecular structure, so an agreement is about to be reached to completely phase out R-22 at the beginning of the 21st century, so it is difficult to continue using such a gas as a refrigerant. , undesirable. Furthermore, when R-22 is used in electric refrigerators, low-temperature equipment, etc., the compression ratio is large, so the temperature of the discharged waste rises too much, leading to decomposition of the refrigerant and deterioration of the oil, resulting in smooth system operation. There is a danger that you will not be able to drive properly. As a measure to suppress such temperature rise, it is possible to use liquid injection, but if this is used, it will reduce the excellent coefficient of performance that the refrigerant originally has. This is disadvantageous in terms of energy conservation.

Means for Solving the Problems The present inventor has found that the refrigerant has a good coefficient of performance, has little negative impact on the global environment even if it were to be released into the atmosphere, and naturally does not cause ignition or explosion. Various research efforts have been made to find a new refrigerant that is free from the dangers of As a result, 1
．． 1. 2. It has been found that 2-tetrafluoroethane meets the requirements for that purpose.

That is, the present invention relates to a freezing/refrigerating/air conditioning system using 1,1.2.2-tetrafluoroethane (hereinafter referred to as R-134) as a refrigerant.

The main physical properties of R-134 used in the present invention are as follows.

Boiling point -19.8℃ Critical pressure 4.62MPa Critical temperature 119℃ Molecular teeth 102.03 Flammability None R-134 used in the freezing, refrigerator, and air conditioner according to the present invention
If necessary, a stabilizer can be used in combination. That is, when a high degree of stability is required under harsh usage conditions, epoxides such as propylene oxide, 1,2-butylene oxide, and glycidol, and phosphors such as dimethyl phosphite, diisopropyl phosphite, and diphenyl phosphite are used. Phytos; thiophosphites such as trilauryl trithiophosphite; phosphine sulfides such as triphenoxyphosphine sulfide and trimethylphosphine sulfide; boron such as boric acid, triethylborate, triphenylborate, phenylphoronic acid, and diphenylphoronic acid Compound;
Phenols such as 2,6-di-tert and butyl para-cresol; Nitroalkanes such as nitromethane and nitroethane; Acrylic acid esters such as methyl nitacrylate and ethyl acrylate; Other dioxane, tert
・Stabilizers such as butanol, pentaerythritol, barisopropenyltoluene; 0.01% by weight of R134
It is possible to add about 5%.

The freezing, refrigeration, and air conditioning systems of the present invention using R-134 as a refrigerant include car coolers, electric refrigerators, showcases, room coolers, package near conditioners, refrigerated containers, water chillers, brineer chillers, drinking water cooling equipment, etc. Examples include freezing, refrigeration, and air conditioning equipment that employ -12 and R-22 as refrigerants.

Effects of the invention R-13 used in the refrigeration/refrigeration/air conditioning system of the present invention
No. 4 is easily decomposable and does not contain chlorine atoms that affect the ozone layer, so there is no risk of causing the problem of ozone layer destruction.

Furthermore, the refrigeration/refrigeration/air conditioning system of the present invention that uses R-134 is different from the current refrigeration/refrigeration/air conditioning equipment that currently uses R-12 as a refrigerant.
Compared to refrigeration and air conditioning equipment, to achieve the same refrigeration capacity, the piston displacement of the compressor must be reduced by 20 to 36%.
It can be said that it is excellent in energy saving because it does not need to be made larger or consumes less power to achieve the same refrigeration capacity.

Furthermore, even when the device of the present invention is used under low-temperature conditions, there is no need to perform liquid injection, so there is little risk of decomposition of the refrigerant or carbonization of oil due to a rise in the temperature of the discharged scum, and the device is highly reliable.

Furthermore, since R-134 used in the present invention has low solubility in polymer compounds, it can be used as is without changing the materials used in existing refrigeration, refrigeration, and air conditioning equipment.

Furthermore, R-134 used in the present invention has excellent thermal stability and is non-flammable, so it also has safety measures that have been adopted in freezing, refrigeration, and air conditioning equipment that use R-12, R-22, etc. as refrigerants. It can be applied using almost the same concept, and the equipment used.

Furthermore, R-134 has advantages over R-134a, such as easier availability of raw materials, easier production, and fewer by-products, so it is also advantageous in that it is cheaper. .

EXAMPLES Examples will be shown below to further clarify the features of the present invention.

Example 1 In a 1 horsepower refrigerator using R-134 as a refrigerant, the evaporation temperature of the refrigerant in the evaporator was 5°C, the condensation temperature was 50°C, and the degree of superheat at the evaporator outlet was 5°C,
The operation was carried out with the degree of supercooling at the condenser outlet set to 2°C.

Table 1 shows the operation results: (I) compressor piston displacement ratio, (II) condensation pressure/evaporation pressure (Pc/
Pe), (m) discharge gas temperature ('C), (TV) refrigeration capacity (kcal/hr), (V) ml pump power and (VI) coefficient of performance (COP). Pc and P
In both cases, e indicates (kg/cd・gauge pressure: the same applies hereinafter).

In addition, in Table 1, R-12, R-
The results when using 22 or R-134a are also shown.

From the results shown in Table 1, it is clear that the air conditioner according to the present invention has excellent performance in terms of low discharge gas temperature and low power consumption.

Example 2 In a 1-horsepower refrigerator using R-134 as a refrigerant, the evaporation temperature of the refrigerant in the evaporator was set to -25°C, the condensation temperature was set to 45°C, the degree of superheat at the evaporator outlet was set to 10°C, and the condensation The operation was carried out with the degree of supercooling at the outlet of the vessel being 5°C.

Table 2 shows the operation results: (I) compressor piston displacement t ratio, (II) condensation pressure/evaporation pressure (Pc/
Pe), (III) Discharge gas temperature ('C), (TV) Refrigeration capacity (kca]/hr), (V)
KW) and (VI) coefficient of performance (C0P).

In addition, in Table 2, R-12, R-
The results when using 22 or R-134a are also shown.

From the results shown in Table 2, A refrigerator according to the present invention includes: Discharge gas temperature is low It also has low power consumption. In this point, It is clear that it has excellent performance.

(Hereafter

Claims (1)

[Claims] (1) Freezing, refrigeration, and air conditioning equipment that uses 1,1,2,2-tetrafluoroethane as a refrigerant.