JPS60173083A - Operating medium for heat pump - Google Patents

Abstract

PURPOSE:To provide an operating medium for a heat pump contg. specified compds. as essential constituents, which improves operating efficiency of the heat pump as compared with those employing conventional heating media and markedly increases heating and cooling capacity per suction air flow of a compressor. CONSTITUTION:The operating medium contains dichloromonofluoromethane and monochloropentafluoroethane as essential constituents. It improves heating capacity and operating efficiency of a heat pump without excessive increase in pressure of condensation. It also increases heating and cooling capacity per suction air flow of a compressor to a marked extent and is of great practical use.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel working medium that can be used in heat pumps and the like.

In the present invention, the term "heat pump" refers not only to heat pumps in a narrow sense that produce high-temperature fluids, but also to heat pumps in a broad sense, including refrigerators and the like that produce cold fluids.

Heat pumps have a wide range of applications, including freezers, refrigerators, air conditioning equipment, heating equipment, hot water supply equipment, and equipment for waste heat recovery. From the standpoint of energy conservation, it is expected that the efficiency of heat pumps will be improved through the development of new working media. In other words, when utilizing heat, it improves the coefficient of performance, which is the ratio between the heating and cooling capacity and the electrical energy required for its operation, and also improves the capacity (heating and cooling capacity) per compressor suction volume of working medium. The development of a cutting-off working medium is desired. Furthermore, when heat pumps are applied to heat utilization equipment, there is a condition that the cost is lower than other methods, and as a working medium, there is no advantage to using it if it is rare and expensive, and it is limited to those that are cheap and easily available.

The present inventors have conducted various studies to meet such demands, and as a result, dichloromonofluoromethane (Freon-21
) and monochloropentafluoroethane (Freon-115
) was found to have superior properties compared to the single substance before mixing. In particular, we have found that a mixture of Freon-115 and Freon-21 having a molar fraction of 0.03 to 0.30 has excellent properties as a working medium for heat pumps.

The present invention will be explained in detail below.

FIG. 1 shows a flow sheet of a heat pump using the working medium of the present invention, where 1 is a compressor, 2 is a condenser,
3.3' is the load fluid piping.

4 is a pressure reducing device, 5 is an evaporator, and e and e' are piping for heat source fluid.

In the heat pump system shown in FIG. 1, the working medium is compressed by a compressor 1 and then led to a condenser 2.
Inside, it is cooled and condensed by the load fluid introduced from the pipe 3. Meanwhile, the load fluid is heated inversely in the condenser 2 and the tube 3
' and then subjected to load heating. Next, the condensed working medium is depressurized by the pressure reducing device 4, and then led to the evaporator 5, where it is heated and evaporated by the heat source fluid introduced from the pipe 6 and discharged from the pipe 6', and then compressed again. 1 and repeat the above cycle.

FIGS. 2 and 3 show the cycles of the working medium in the heat pump system shown in FIG. 1 on pressure-enthalpy diagrams.

When saturated vapor as a working medium is adiabatically compressed, a wet state is shown in Fig. 2, and a dry state is shown in Fig. 3.

The change in the working medium due to the compressor in FIG. 1 is the change from 8 to 9 or from 13 to 1'4 in FIGS. 2 and 3.
The change in working medium due to the condenser is from 9 to 11 or 14
17, the change in working medium due to the pressure reducing device is 1
For a change from 1 to 12 or from 17 to 18, a change in the working medium by the evaporator corresponds to a change from 12 to 8 or from 18 to 13, respectively.

The operating conditions for the heat pump system shown in FIG. 1 using the working medium of the present invention are that the suction temperature of the compressor (temperature numbered 8 or 13) is 5°C, and the temperature at the start of condensation of the working medium in the condenser (temperature numbered 9 or 13) is set at 5°C. or temperature of 15) to 40℃,
The temperature was set at 70°C.

Table 1 shows the coefficient of performance, heating capacity per compressor suction volume (hereinafter referred to as heating capacity), and pressure of the working medium in the condenser in the heat pump system using the working medium of the present invention, along with comparative examples.

As understood from Table 1, the coefficient of performance of a heat pump using the working medium of the present invention containing a mole fraction of Freon-115 of 0.03 to 0.30 is
This is an improvement over the case where 115 is used alone. In particular, when using the working fluid of the present invention in which the mole fraction of Freon-115 is 0.10, under operating conditions where the condensation start temperature is 40°C, the coefficient of performance is 6 compared to when Freon-21 is used alone. The coefficient of performance was improved by 52% compared to when Freon-115 was used alone. Furthermore, under operating conditions where the condensation start temperature is 70"C, if Freon-115 is used alone, the critical temperature of Freon-115 (80℃
) It is not practical to use Freon-115 alone because it will be used nearby and the coefficient of performance will be extremely low.

Furthermore, the heating ability is improved when the working fluid of the present invention is used, compared to when Freon-21 is used alone, regardless of the condensation start temperature of 40°C or 70°C. This can be understood from Table 1.

In other words, the working medium of the present invention has characteristics that can improve the heating capacity per suction volume of the compressor and also improve the coefficient of performance in a heat pump using the working medium without extremely increasing the condensing pressure. It can be said. Furthermore, dichlorodifluoromethane, which has traditionally been used as a working medium for air conditioning and medium-temperature heat pumps, is the first
When operating under the same operating conditions as when the table was obtained, the condensation start temperature was 70°C and the condensation pressure was 19.3kg/
The coefficient of performance for cyA was 3.77, and it was found that when the working medium of the present invention was used, the condensation pressure was lower and improved by 23% at the highest value of the coefficient of performance.

As explained above, when the working medium of the present invention is applied to heat pumps in a broad sense, including heating and cooling, etc., the coefficient of performance is improved compared to heat pumps using conventional working medium, and moreover, the working medium of the present invention is improved per the same suction air volume of the compressor. The heating and cooling capacity of the system can be significantly increased, resulting in extremely useful effects in practice.

Table 1 Condensation start temperature 40℃ Condensation start temperature 70’C

[Brief explanation of drawings]

Fig. 1 is a flow sheet of a heat pump for explaining one embodiment of the present invention, and Figs. 2 and 3 are fluorocarbon-21
FIG. 2 is a pressure-enthalpy diagram showing a cycle using a CFC-115 mixture system as a working medium. Among the agents 1) Akira's agent Ryo Hagiwara - Kaya / Trap Kaya 2)'g! 1 child 3 review〉71 bi entanlehi'

Claims (1)

[Scope of Claims] A working medium for a heat pump, characterized in that it contains cyclomonofluoromethane and monochloropentafluoroethane as essential components. 2. The mole fraction of monochloropentafluoroethane is 0.
03 to 0.30.