Exam Question
(a) What are the reasons of frosting in the refrigeration chambers and its effect. (6)
(b) What are the methods used for defrosting refrigerated chambers? (6)
(c) What is the arrangement of Reefer Chamber drains? (4)
Class 4 (4th Engineer)
MEP
📅 Jun 2023
Reference Answer
### (a) Reasons for Frosting in Refrigeration Chambers and its Effects (6 Marks)
Frosting on the evaporator coils of a refrigeration chamber is the result of moisture (water vapour) present in the chamber's air solidifying upon contact with surfaces that are below the freezing point of water (0°C). The primary sources of this moisture and the reasons for frost formation are as follows:
**Reasons for Frosting:**
1. **Air Ingress:** This is the most significant source of moisture. Warm, humid ambient air enters the refrigerated space, carrying a substantial amount of water vapour which subsequently freezes onto the cold evaporator coils.
Frosting on the evaporator coils of a refrigeration chamber is the result of moisture (water vapour) present in the chamber's air solidifying upon contact with surfaces that are below the freezing point of water (0°C). The primary sources of this moisture and the reasons for frost formation are as follows:
**Reasons for Frosting:**
1. **Air Ingress:** This is the most significant source of moisture. Warm, humid ambient air enters the refrigerated space, carrying a substantial amount of water vapour which subsequently freezes onto the cold evaporator coils.
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