Question 1 of 27070
Q
Concerning frost appearing on one set of evaporator coils of a multi-box, direct expansion type refrigeration system, what is true?
A
the frost will increase the value of superheat to the fluid leaving the coils
B
the frost can be quickly removed by simply shutting off fluid flow to the coils
C
the frost can be removed by passing hot vapors through the coils
D
the frost will assist in increasing the refrigeration effect
Question 1 / 270705eccef9dbacbc34ba4d460b2
Question 1 of 270705eccef9dbacbc34ba4d460b2

Concerning frost appearing on one set of evaporator coils of a multi-box, direct expansion type refrigeration system, what is true?

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Question 1 of 27070
Q

Concerning frost appearing on one set of evaporator coils of a multi-box, direct expansion type refrigeration system, what is true?

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🔍 Key Concepts

• Behavior of direct expansion refrigeration evaporator coils • Effect of frost/ice buildup on heat transfer and coil performance • Normal method used on ships for defrosting evaporator coils

đź’­ Think About

• Think about whether frost on the outside of the coil helps or hurts heat transfer between the air and the refrigerant. • Consider what happens to refrigerant temperature and superheat when the coil surface becomes insulated by frost. • Ask yourself what common defrost methods are actually installed and used on marine refrigeration systems.

âś… Before You Answer

• Does frost act more like an insulator or a good conductor on the coil surface? • Is simply stopping refrigerant flow through a cold coil likely to melt or keep the frost/ice? • Is there a standard practice involving hot gas/vapor defrost on multi-box, direct expansion systems?