Ammonia for more than 100 years

More mixtures in the future

STAL participates in project

The HFC group also includes R32, R125, R143a and R132a. Because of their flammability, most of these substances are not placed in the lowest risk class. Since they are odourless and denser than air, their usage as pure media is alsolimited but in mixtures (together with R134a, for example) it is possible to achieve suitable alternatives to HCFC. An extensive programme initiated by the Air Conditioning and Refrigeration Institute in the USA, STAL Refrigeration, is being conducted with these mixtures to evaluate possible alternatives to R22 and is participating actively in the European part of that programme.

Mixtures will be much more common than before. This is true also for non-azeotropic mixtures, although it is then necessary to limit the temperature glide in order to avoid changes in the compound, should a leak occur. The use of these mixtures will also re­quire higher technical skill – for example, the HFC media operating with the new lubricating oils are more hygroscopic, which means that it is more difficult to keep moisture out of the systems. Another disadvantage of carbon based refrigerants is that they contribute to global warming when discharged. No limitations for usage have been introduced, but in this respect both users and pro­ducers feel uncertain about the future.

Ammonia is a traditional refrigerant which has been in use for over 100 years and which does not affect the ozone layer or add to global warming. Ammonia is poi­sonous and – under certain circumstances – explosive. Even so, ammonia has kept its position as the foremost refrigerant in industrial applications thanks to continuous developments of the related safety regulations. Consequently, ammonia plants can today be used without any limits.

Exercise 4. Find the Russian equivalents for the following:

a circuit process, the lowest risk class, toxicity and flammability, lubricating oils, depletion of the ozone layer, to keep moisture, users and pro­ducers, under certain circumstances, the foremost refrigerant, safety regulations, industrial applications, in this respect, sub-cooling.

Exercise 5. Find the English equivalents for the following:

не иметь ограничений, недостаток, высокие технические навыки, оценивать возможные альтернативы, постоянное усовершенствование, чувствовать неопределенность, избегать изменений, вносить вклад, глобальное потепление, благоприятный, преимущественно.

Exercise 6. Complete the sentences using information from the text:

1. Instead,…

2. Even so,…

3. Because of their flammability,…

4. The first step was…

5. This discovery led to…

6. However,…

7. Since they are…

Exercise 7. Fill in the blanks with prepositions about, of, for, out, to, in:

1. Ammonia is a traditional refrigerant which has been … use … over 100 years.

2. This is true also … non-azeotropic mixtures.

3. No limitations … usage have been introduced, but … this respect both users and producers feel uncertain … the future.

4. It is more difficult to keep moisture … … the systems.

5. They contribute … global warming when discharged.

Exercise 8. Say if the sentences are true or false:

1. The use of these mixtures does not re­quire higher technical skill.

2. CFC replacements based on HCFC compounds are only temporary solutions.

3. Ammonia is not poi­sonous and explosive.

4. Mixtures won't be more common than before.

5. Another advantage of car­bon based refrigerants is that they do not contribute to global warming when discharged.