Refrigeration Basics.ppt

15 Ways to Improve Chiller EfficiencyDefinition
Refrigeration is the transfer of heat from one place to another by a change in state of a liquid.
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Heat which causes a change in temperature of a substance
Latent Heat
Heat energy absorbed in the process of changing form of a substance without a change in temperature or pressure. Heat energy that cannot be measured with a thermometer.
32o
What type of heat was involved
32o
Most heat transfer occurs
from latent heat transfer
Energy required to convert 1 lb of water @212F to steam @ 212°F =970 Btu
Energy required to heat 1 lb of water from 44°F to 54°F =10 Btu
Btu (British Thermal Unit) -- Amount of energy required to heat one pound of water one degree F.
Latent Heat
If in our example one pound of ice melted how many BTU’S were added to the water?
32o
32o
evaporate to produce one ton of cooling?
Condenser Water
1 gallon = 8.3 lbs.
Subcooling
Cooling the refrigerant below its condensing temperature. A refrigerant must be in a complete liquid state before it can be subcooled.
14.7 PSIA in an enclosed vessel is water in
a subcooled state?
14.7 PSIA in an enclosed vessel is water in
a subcooled state?
Superheat
To raise the temperature of a vapor beyond its boiling point. No liquid can remain when a refrigerant is superheated.
Superheat
Cooling the refrigerant below its condensing temperature. A refrigerant must be in a complete liquid state before it can be subcooled.
14.7 PSIA in an enclosed vessel is steam in
a superheated state?
14.7 PSIA in an enclosed vessel is steam in
a superheated state?
R-11 = + 75o
R-123 = + 82o
R-12 = - 21o
R-134a = - 15o
R-22 = - 41o
Heat required to raise 1 lb. water 1 degree = 1 BTU
12,000 BTU / hour = 1 ton of refrigeration
1,000 BTUH = 1 MBH

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Refrigeration Basics.ppt