Retrotec USACE - Manual (Page 264)

D134 ENERGY & PROCESS ASSESSMENT PROTOCOL
Every time the walk-in cooler or freezer door opens, warm air infi ltrates the
box, increasing energy use of the refrigeration system. Plastic strip curtains
reduce warm air infi ltration by 75% and help maintain the safe internal tem-
perature range during entrance. They also serve as a redundant “backup” to
the walk-in box door when it is unintentionally left ajar. An automated door
closer ensures that the walk-in box door closes securely (Figure D219). Annual
operating cost savings from an automated door installation range from $130
to $190.
D.7.10.4 Ineffi cient Walk-in Cooler and Freezer Evaporator Fan
Motors (Ineffi ciency)
Figure D220. Walk-in cooler and freezer
evaporator with three fans.
Walk-in cooler and freezer evaporator fan motors (Figure D220) run 24/7,
recirculating air through the evaporator. Typical standard-effi ciency shaded
pole motors have an energy rate of 135 W, versus 45 W for a high-effi ciency
electronically commutated motor. An electronically commutated motor gen-
erates less heat, further reducing a walk-in box operating cost. Annual oper-
ating cost savings from replacement of ineffi cient motor is about $100 per
motor.
D.7.10.5 Unnecessary Use of Refrigerator and Freezer Anti-Sweat
Door Heater (Waste)
Figure D221. Antisweat door heater switch.
Refrigerator and freezer anti-sweat door heaters consume 500 W per door
and are often unnecessary in dry climates—e.g., California. Turning off the
anti-sweat door heater (Figure D221) results in saving an approximate annual
operating cost of $75 per door.