Unit 25 - Chapter 114 Flashcards
What group does r-22 or freon-22 belong to?
A1
Which of the following characteristics is common in all group b refrigerants?
High toxicity
The ideal commercial refrigerant should
Be environmentally friendly
Ammonia refrigerants
Are well suited for industrial and commercial refrigeration
What’s the refrigerants that is nonflammable, odourless, nontoxic, has a boiling point of -40.6, and doesn’t have a corrosive effect on metals?
Freon 22
The refrigerant r-11 belong to the group
A1
Which of the following is a thermodynamic property of heat?
- entropy
- Enthalpy
- density
- volume
The property which has to be known for the calculation of the size of control valves and piping is
Density
The refrigerating effect of a refrigerant is
Equal to its latent heat of evaporation
The standard refrigeration cycle is used to compare refrigerants and machines operating under comparable conditions, which are
30 degrees condensing and -15 evaporating
The latent heat of fusion of ice is
335 kJ per 1 kg
The ability if a refrigerant to be dissolved into oil is called
Miscibility
Which is not a physical property of refrigerants?
Density
Ammonia is the only commonly use refrigerant which has the physical property of
Flammability
Molecular mass is a dependent factor on what physical property?
Leakage tendency
Freon 22
Is a heat transferring medium
What is not a physical property of refrigerants?
Corrosively
Which of the following has the highest boiling point?
Water
The amount of heat absorbed by a refrigerant in the evaporator is equal to the
Latent heat of vaporization minus heat required to flash the liquid due to the pressure drop
R22
Is nontoxic
R134a belongs to group
A1
R134a is
Non toxic and non flammable
