Refrigeration

Refrigeration is now part of our way of life. It would be inconceivable for it to be any other way. It has even become an essential ingredient and a "sine qua non" in improving our quality of life.

• The cooling chain enables the storage, transport and use of food items in ideal hygienic conditions, reducing losses and waste.
  
• Refrigeration of essential medical products such as vaccines and blood, is often indispensable for ensuring their preservation.
  
• Refrigeration of technical equipment such as large computers systems, through to the most sophisticated medical equipment (RMN for example), is also crucial.

Thermal insulation using high-efficiency HFC blown foams reduces energy consumption of the refrigeration installations 

Refrigeration applications vary widely in size and temperature level:

• Domestic refrigerators require 60 to 140 watts of electrical power and contain 40 to 180 grams of refrigerant.
• Industrial and cold storage refrigeration systems have power requirements up to several megawatts and contain thousands of kilograms of refrigerant.
• Refrigeration temperature levels range from +15 to –70 degrees Centigrade.

Potential market size for these equipments may approach EUR 100,000 million annually.

The following table summarizes the various types of refrigeration, and the HFCs used in each application.

The Cooling Chain

Cool chain management is essential for preserving the harvested quality of fresh produce.

Effective cool chain management begins on the farm and ends in the refrigerator at home.

Any effort to reduce the ruptures in the cool chain will have a positive effect on optimizing the shelf life and quality of fresh produce.

Temperature management is one of the most important factors affecting the quality of fresh produce. There is an optimum storage temperature for all products

This implies a number of steps where refrigeration is essential, by which the harvested or picked material will be :

•  Transported in refrigerated transport
• Held in a cold store and packed for selling
• Transported to a chilled depot
• Transferred to a shop or a supermarket
• Kept by the consumer at the appropriate Temperature
  

  

Refrigeration Applications

More information

Refrigeration and climate

Because of their energy consumption and of possible emissions of the refrigerant, the potential climate impact of refrigeration is an important issue.  For many years all the players of the industrial chain have collaborated to bring solution through technical innovation and better practices.

The brochure   "HFCs, refrigeration and air conditioning. Minimising climate impact, maximising safety"
(max. 2 MB) addresses the essential elements of this important question.

Refrigeration is also one of the topics discussed during the Workshops held by EFCTC on the responsible use of HFCs.

How does refrigeration work?

Nearly all current applications practice refrigeration by vapor compression technology but the diversity of applications and conditions has required unique optimization efforts over decades. The following links provide simple explanations.

The vapor compression scheme : refrigeration cycle http://www.warmair.com/html/refrigeration_cycle.htm

Heat Pumps Basics

Understanding heat pumps

Designation and safety classification of refrigerants

Sources : American standard ANSI/ASHRAE 34 (2001)“Designation and Safety Classification of Refrigerants”. (ASHRAE is the American Society of Heating, Refrigerating and Air- Conditioning Engineers)

http://www.iifiir.org/2endossiers_fiches_classification.htm

Designation of Refrigerants

The basis of the designation of the refrigerants fluids is based on a numbering system

1 - Pure Fluorocarbons (HFC) refrigerants and their blends  

The refrigerants are numbered with an R-, followed by the HFC-number, given by the rules of the fluorocarbons numbering system.

Isomers are identified with lower cases (ex R 134a).

HFC refrigerant blends (i.e. mixtures of pure refrigerants), are numbered after the internationally accepted ASHRAE nomenclature.

Blends having the same pure components but with different compositions are identified with upper cases (ex R 404A). Refrigerants having the form R-4xxx are zeotropic blends of two or more refrigerants, while those with the form R-5xxx are azeotropes.

The numbers are in chronological order of the refrigerant’s approval by ASHRAE.

2 - Miscellaneous organic compounds

Organic compounds are numbered with the same system as Fluorocarbons.

Ex : Propane C₃H₈ (R-290)

Nb of C atoms is X = 3
Nb of H atoms is Y = 8
Nb of F atoms is Z = 0

Substract 90 from 380 = 290

3 - Inorganic compounds

Inorganic compounds shall be assigned a number in the 700 series, identification numbers are formed by adding the relative molecular mass of components to 700.

Examples:      R717 = ammonia (molecular mass 17)

                     R718 = water (molecular mass 18)

                     R744 = CO₂ (molecular mass 44)

Safety classification of refrigerants  

The safety classification consists of two alphanumeric characters (e.g. A2); the capital letter corresponds to toxicity and the digit to flammability.  

1 - Toxicity classification

Refrigerants are divided into two groups according to toxicity:

• Class A signifies refrigerants for which toxicity has not been identified at concentrations less than or equal to 400 ppm;
• Class B signifies refrigerants for which there is evidence of toxicity at concentrations below 400 ppm.

 2 - Flammability classification

Refrigerants are divided into three groups according to flammability: 

• Class 1 indicates refrigerants that do not show flame propagation when tested in air at 21°C and 101 kPa;
• Class 2 indicates refrigerants having a lower flammability limit of more than 0.10 kg/m³ at 21°C and 101 kPa and a heat of combustion of less than 19 kJ/kg;
• Class 3 indicates refrigerants that are highly flammable as defined by a lower flammability limit of less than or equal to 0.10 kg/m³ at 21°C and 101 kPa or a heat of combustion greater than or equal to 19 kJ/kg.

3 - Mixtures

Mixtures, whether zeotropic or azeotropic, with flammability and/or toxicity characteristics which may change as the composition changes during fractionation, shall be assigned a safety group classification based on the worst case of fractionation.
Example: R404A is classified A1

Classification of main refrigerants