In a vapour compression refrigeration system, a throttle valve is used in place of an expander because
A. It considerably reduces mass of the system
B. It improves the C.O.P., as the condenser is small
C. The positive work in isentropic expansion of liquid is very small
D. It leads to significant cost reduction
Answer: Option C
Solution(By Examveda Team)
In a vapour compression refrigeration system, a throttle valve is used in place of an expander because The positive work in isentropic expansion of liquid is very smallThis Question Belongs to Mechanical Engineering >> Refrigeration And Air Conditioning
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Comments ( 2 )
Nusselt number (NN) is given by
A. $${{\text{N}}_{\text{N}}} = \frac{{{\text{h}}l}}{{\text{k}}}$$
B. $${{\text{N}}_{\text{N}}} = \frac{{\mu {{\text{c}}_{\text{p}}}}}{{\text{k}}}$$
C. $${{\text{N}}_{\text{N}}} = \frac{{\rho {\text{V}}l}}{\mu }$$
D. $${{\text{N}}_{\text{N}}} = \frac{{{{\text{V}}^2}}}{{{\text{t}}{{\text{c}}_{\text{p}}}}}$$
In case of sensible heating of air, the coil efficiency is given by (where B.P.F. = Bypass factor)
A. B.P.F. - 1
B. 1 - B.P.F.
C. $$\frac{1}{{{\text{B}}{\text{.P}}{\text{.F}}{\text{.}}}}$$
D. 1 + B.P.F.
The undesirable property of a refrigerant is
A. Non-toxic
B. Non-flammable
C. Non-explosive
D. High boiling point
The desirable property of a refrigerant is
A. Low boiling point
B. High critical temperature
C. High latent heat of vaporisation
D. All of these
Option D correct
Options D is correct
Positive work of an isentropic expansion is large.
But it could achieve by paying extra money on it.