Improving: Freezer / Refrigerator Efficiency
Item in parentheses is the item number in paper, CASE_Walk-In_Cooler.pdf (enclosed with this report)
Percentage savings are based upon walk-in cooler/ freezer
Items in Bold are most highly recommended
Keep door shut - use automatic door controls 8%(12)/23%(12) (Reduce by 50%, as strip curtains are also used to 4%/12%)
Check door seals.
Check temperatures. Refrigerator should be between 35ºF & 38º F; freezer should be between -14ºF & -8ºF.
Ensure that condenser coils are clean. (They are.)
Ensure that evaporator coils are clean (in box).
Replace strip curtains - must go to floor as cold air drops 9%(10)/24%(10) - strip curtains are old and worn with gaps. Savings with new curtains: 6%/ 5%
Ensure that lamps are very efficient.
Electronic lighting ballasts 1%(8)
Adjust floating head pressure to adjust to outside temperature. (18%(1))
Ensure that refrigerant charge is correct
Defrost cycles driven by other than time interval (e.g., when air flow from evaporator is disrupted) /(2%(3))
Evaporator fan motors very efficient CASE_Walk_In_Cooler.pdf suggests (Page 5) using permanent split capacitor (PSC) or Electronically Commutated Motors (ECM). (This could also be used for condenser fans, but savings would be much less.) 4%(5)/4%(6).
Condensing unit fan motors 2%(7)/7%(8)
Adjust speed of evaporator fan motors to slow when not cooling (FrigiTech) Cost: 09 $219; 07 $249 - place sense coil on control circuit; contact: Jack Joyner 4%(5)/4%(6) Frigiteck also makes there type of device.
If the back condenser unit is more efficient, then have it come on first (at higher temperature)
Ensure that all fans operate correctly (the upper left condenser fan in the back freezer C-U seems to be defective)
Ensure that the suction line is adequately insulated (it isn't now). The outer diameter of the current insulation is 3.25". The length of the pipe to be insulated is 36', with 2 elbows. Totals for freezer: 72' + 2 elbows. For refrigerator: 72' + 2 elbows. Protect with white PVC cover.
Increase envelope insulation (Compute energy gain into box without and with additional insulation) (0%(4))/4%(5))
Raise the floor to allow insulation to be placed under the floor.
OR: Apply sheets of insulation under racks - Assume 40% of area (432 ft2) - Savings: $371
Hot gas defrost. /(4%(4))(Again see CWIC.pdf)
High efficiency fan blades 6%(9)/5%(9)
Ambient subcooling (9%(2))
Purchase Ice Machine with remote condensing unit, such as Scottsman CME506
Move Ice Maker Outside of Cooler
Raise Freezer temperature from -5ºF to 0ºF
Replace reciprocating compressors with scroll compressors - 16% savings.
Carefully select and set expansion valve.
- Combine 7 & 8 - efficient fixtures
- Use automatic occupancy sensors to control lighting