aux systems ( refrig & AC)

Question 1

AC/ FRIDGE system usage

Answer 1

cooling of cargo and food stores, medical supplies, cooling of electronic spaces and equipment, AC

Question 2

refrigerant

Answer 2

working substance, repeated transformations between liquid and vapor in a continuous closed cycle

Question 3

components of refrigeration cycle

Answer 3

evaporator, compressor, condenser, thermostatic expansion valve (TXV)

Question 4

evaporator

Answer 4

keeps equipment, food or air cold. Heat exchanger, heat is transferred into the cold pipe

Question 5

compressor

Answer 5

keeps refrigerant circulating thru system. compresses low pressure refrigerant vapor to high refrigerant vapor, increase in energy provides driving force to allow the refrigerant to flow thru the system

Question 6

condenser and receiver

Answer 6

heat exchanger, uses seawater, discharges heat from refrigerant overboard, refrigerant vapor converts to liquid, returned to starting point as high pressure /temp sub-cooled liquid

temporary storage space for sub-cooled refrigerant, liquid refrigerant prevents vapor from entering thermostatic expansion valve (TXV) prevents submersion of condenser tubes in liquid refrigerant

Question 7

thermostatic expansion valve (TXV)

Answer 7

controls flow of refrigerant to evaporator, metering device, valve opens when temp above set point. liquid refrigerant enters at a much higher pressure. liquid refrigerant leaves at a much lower pressure. liquid refrigerant transforms to vapor as pressure drops. mixture of liquid and vapor refrigerant enters evaporator coils, absorbs heat from evaporator and continues cycle (FREON/REFRIGERANT)

Question 8

refrigerant properties

Answer 8

high latent heat of vaporization, able to absorb more heat for max cooling, non-toxicity, stability, nonflammable/non-explosive, ease of leak detection, low cost, readily available, R-12, R-1114, R-134A

Question 9

phosgene gas hazard

Answer 9

created when refrigerant exposed to high temps

Question 10

phosgene gas hazard handling procedures

Answer 10

goggles and gloves worn to avoid eye irritation and frostbite

Question 11

phosgene gas asphyxiation hazard

Answer 11

havier than air, refrigerant displaces oxygen in the lungs, death by suffocation