New refrigerants

New hydrofluorocarbons (HFCs) are replacing the chlorofluorocarbons (CFCs) and hydrochlorofluorocar-bons (HCFCs) phased out to lessen damage to the ozone layer. The DuPont website lists physical properties for a number of their refrigerants. 

These physical property tables give three vapor pressure points that can be connected on your favorite Cox type vapor pressure chart for a quick approximation of the whole range. These three points are  

If more accurate vapor pressure data across the range are needed, DuPont can supply them. I received full-range vapor pressure data for many products on request from their very helpful SUVA Refrigerants Division. 

DuPont deNemours and Company website, Physical properties and ASHRAE standard 34 classification of SUVA refrigerants.  

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For refrigeration compressors Miscibility with the refrigeration fluids (including compressors with the new refrigeration fluids) Adapted composition... 

For example a consumer wishes to buy a new refrigerator. The high-efficiency model (offering services identical to the standard model) costs 60 more but uses 400 kWh/year less electricity. The consumer expects to keep the refrigerator for ten years and has a discount rate of 5 percent. The cost of conserved energy in this case is calculated as follows ... 

Sharp Corporation promotes its new refrigerator, which includes the first built-in LCD. (Corbis Corporation)... 

This chapter is about the new refrigerants and the new attitude needed in design, maintenance and servicing of refrigeration equipment. 

Hydrocarbons such as propane and butane are being successfully used as replacement and new refrigerants for R12 systems. They obviously have flammable characteristics which have to be taken into account by health and safetyrequirements. However, there is a market for their use in sealed refrigerant systems such as domestic refrigeration and unitary air-conditioners. 

It is desired to find a replacement for Freon-12 as an alternative refrigerant [Duvedi Achenie (1996)]. The objective is to find replacements that have the same refrigerant related properties as Freon-12 but without the harmfull environmental properties (such as the Ozone depletion potential) - The new refrigerant must absorb heat at temperatures as low as -1.1°C and reject heat at temperatures as high as 313 K. It must also respect the following characteristics ... 

Also, to reduce the amount of refrigerant needed, the latent heat of vaporization must be as high as possible. The latent heat of vaporization of Freonl2 is 18.4kJ/mol, so to assure that the new refrigerant is at least as good as the... 

Refrigeration technology is moving into a new phase with the introduction of hydrofluorocarbons that combine the safety of chlorofluorocarbons with a much lower environmental impact The considerable care bemg taken to choose the new refrigerants under the close scrutiny of the public and regulatory bodies will ensure that the new products will benefit mankind for years to come... 

W.E. Keller, Magnetic Refrigeration The Basis for a New Refrigeration Technology, LALP-82-34, Los Alamos National Laboratory Report, 1982. 

In order to size the compressor of a new refrigerator, it is desired to determine the rate of heat transfer from the kitchen air into the refrigerated space through the walls, door, and the top and bottom section of the refrigerator (Fig. 2-11). In your analysis, would you treat this as a transient or steady-state heat transfer problem Also, would you consider the heat transfer to be one-dimensional or multidimensional Explain. 

A number of new refrigerants have been proposed during the last several years as candidates to replace R-22 and R-502 in industrial refrigeration systems (73). International accords such as the Montreal Protocol on CFC production and other accords concerning pollution and gas emissions to the atmosphere in particular prompt a review of the refrigerants used in the margarine industry (52, 74). 

The industry should aheady consider the effects of the new environmental policies on its possible need for new refrigeration equipment or for modification... 

Kobayashi, M. Development of new refrigeration system and optimum geometry of the vapor condenser for pharmaceutical freeze dryers proceedings of the 4th International drying symposium, Kyoto, Japan, July 9-12, 1984 Toei, R.R., Mujumdar, A., Eds. 2, 464-471. 

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