Chapter 2 Page 2
2. Safe and Non-Toxic
R134a is classified as an A1 class refrigerant. The letter A starts off as the lowest Toxicity and the number 1 is the lowest flammability, See the chart to the left with examples of refrigerants and their classifications.
3. Easy to liquefy at a moderate pressure and temperature.
Low temperature decreases the energy of gaseous molecule bringing them closer, on the other hand increasing pressure also decreases the intermolecular distance thereby favouring the formation of liquid. Examples are R-12, R-134a, R-600
4. High latent-heat value (able to absorb a large quantity of BTU heat units).
There is Latent heat and Sensible heat.
Sensible Heat is heat that can be measured with a thermometer - Example when you put a glass of water in the refrigerator from the sink it may be 70 degrees, as it sits in the refrigerator it can be as cold as 32 degrees but still be in liquid form.
Latent Heat can not be measured by a thermometer, and Latent Heat is the heat added or removed for a substance such as water can turn from a liquid to Solid or a liquid to vapor.
When we are talking about refrigerants in a sealed system the refrigerant is changing from a liquid to vapor then back again. Using water as an example this change of state happens at 212 degrees Fahrenheit. This temperature does not work well for air conditioning or refrigeration. R134a turns from a liquid to a vapor at -15.34 Degrees.
BTU's - This is measurement of heat energy - an example of 1 BTU is 1 pound of water the heat added to raise that water 1 degree Fahrenheit.