D3-1 Principles of Refrigeration Flashcards
What type of heat is referred to when the transfer of thermal energy from a substance results in a decrease in temperature?
Sensible heat
What type of heat is referred to when energy is absorbed by a substance causing a change in its physical state?
Latent Heat
What three substances are used in an ammonia absorption refrigeration system?
Ammonia, hydrogen, and water
What is the pressure of an ammonia absorption refrigeration system?
200 to 230 Psig
An ammonia/water absorption refrigeration system cannot chill air below freezing due to the system using water (the water will freeze).
TRUE / FALSE
FALSE
What does lithium bromide act as in a lithium bromide absorption refrigeration system?
Absorbent
What does water act as in a lithium bromide absorption refrigeration system?
Refrigerant
What pressures do lithium bromide absorption chillers operate between?
1 to 10 kPa
What are the characteristics of ammonia used in an absorption refrigeration system?
Colourless and a strong odor
What are the characteristics of lithium bromide used in an absorption refrigeration system?
Reddish in colour and a strong odor
At what level of ammonia concentration (ppm) should personal protective equipment be used if there is a possibility of exposure?
Above 50 ppm
At what level of ammonia concentration (ppm) is the maximum allowable averaged over an eight-hour period?
Above 25 ppm
What are the explosive upper and lower limits of ammonia in air?
15% and 28%
Lithium bromide burns skin on contact.
TRUE / FALSE
FALSE
What are the explosive upper and lower limits of lithium-bromide in air?
lithium-bromide is not explosive
