Danfoss AK-CC55 Water Loop - Electrical Defrosting; Hot Gas Defrosting; Natural Defrost; Start of Defrost

1: Electrical
2: Hot gas defrost (Simple)
3: Natural
Electrical defrosting
At electrical defrost, an electrical heater is placed in front of the evaporator and the fan will “pull” the hot air through
the evaporator during defrosting.
Figure 26: Electrical defrosting
Danfoss 84B8310
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Hot gas defrosting
At hot gas defrosting, the compressor will be running and a hot gas valve (HGV) is bypassing the discharge gas to
the evaporator inlet and the evaporator is defrosted by means of the hot gas. Here the evaporator fans are normally
not running and if a condenser fan is dened, it will not be running during the defrost sequence.
Figure 27: Hot gas defrosting
Danfoss 84B8311
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HGV
Natural defrost
At natural defrost the ice is melted by only running the fans and thereby circulating air through the evaporator.
Figure 28: Natural defrost
Danfoss 84B8312
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Start of defrost
A defrost can be started in dierent ways:
Interval:
Defrost is started at xed time intervals like e.g. every eighth hour. An interval must ALWAYS be set to a "higher"
value than the period set between two defrostings when a schedule or network signal is used.
Week schedule:
Here defrost can be started at xed times of the day and night. However, max. 6 defrosts per day.
Contact:
Defrost is started with a contact signal on a digital input.
© Danfoss | Climate Solutions | 2022.04 BC378540472015en-000101 | 19
AK-CC55 Water Loop