Refrigeration and air conditioning can be divided into 3 types of equipment arrangements or operations
1. Direct:
-Dry
-Flooded
2.Indirect
-Using water or eutectic solutions
-Dry
-Flooded
3. Liquid recirculation
-Flooded
The above systems types can use:
-Single compression
-Multistage compression
Indirect System Types
An indirect open spray system that which the secondary refrigerant is in direct contact with the air or other substance to be cooled or heated
Examples: Fast food freezing applications, cooling tower applications
Double indirect open Spray
A double indirect open spray system is one in which the secondary refrigerant from an indirect open spray system is heated or cooled by the secondary coolant circulated from a secondary enclosure
Indirect closed System
An indirect closed system is one in which a secondary refrigerant passes through a closed circuit in the air or other substance being cooled or heated
Examples: Chilled water AC systems, skating or curling rinks, hydronic systems for heating
Indirect Vented Closed System:
An indirect vented closed system is one in which the secondary refrigerant passes through a closed circuit in the air or substance being heated or cooled. Expect that the evaporator or condenser is placed in an open/ vented tank.
Examples: Chilled water A/C systems, Food processing applications
Indirect Systems
Applied to skating + curling rinks
Characteristics of Each
Skating rinks = normal ice temp = hockey 22F/ Normal 24-26F
Curling rinks = Normal ice rinks = 24F
*Note
Brine temp. maintain approx. 10F lower then actual ice temp
Actual ice temp can be maintained by ice T-stat or brine T-stat (return)
Ice thickness = 1.5 inches
*Note
Temp drop through a chiller = 2F at a flow rate of 10-15 GPM/ ton and brine velocity 130-150 FPM
Size of Rinks
-Hockey rinks = 85-200 feet
-Curling rinks = 14 to 146 feet
General plant Requirements
-Hockey rinks = 135-185 sq/ ft/ ton
-Curling rinks = 150-235 sq/ ft/ ton
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