ME 433 - Q1E - P2

What is the chemical formula of butane?

• C₂H₅CI
• C₃H₈
• C₂H₄O₂
• C₄H₁₀

Type of refrigerant control which maintains pressure difference between high side and low side pressure in refrigerating mechanism.

• Suction valve
• Expansion valve
• Service valve
• Solenoid valve

The dividing point between the high pressure and low pressure sides of the refrigerant cycle occurs at the:

• expansion valve
• compressor
• condenser
• cooling coil

Boiling temperature of Freon 12 is:

• -33.33°C
• -78.5°C
• -29.8°C
• -40.7°C

Boiling temperature of Freon 22 is:

• -33.33°C
• -29.8°C
• -78.5°C
• -41.04°C

The way to remove frost from a direct –expansion finned – tube evaporator is to:

• send hot gas through the coil
• scrape off frost
• wash with warm water
• shut down warm let frost melt

You want to change refrigerants in a Freon -12 plant using a reciprocating single – acting compressor, Which refrigerant requires the smallest amount of change to the system?

• Carbon dioxide
• Ammonia
• Methyl chloride
• Aqua ammonia

Soft copper tubing that is used for refrigerant piping, erected on premises containing other that Group 1 refrigerant must be protected by _____.

• supporting it by approved clamps
• limiting its length between supports up to 10 feet
• a rigid or flexible metal enclosure
• wrapping it with insulation tape throughout its length

A Freon-12 refrigeration system is fitted with thermal expansion valves. The valves are rated in:

• pound per minute
• superheat setting
• tons of refrigeration
• cubic feet per minute

The vapor cycle in thermal efficiency as the refrigeration cycle is to the _____.

• energy efficiency ratio
• COP for a refrigerator
• COP for a heat pump
• Carnot efficiency