Thermo Final Exam questions n
answers rated A+
for a refrigeration cycle, what must be true? - correct answer ✔✔Qout,net = Win,net
The conversation of entropy applies to a car engine (t/f) - correct answer ✔✔false
what is considered a conceivable cycle - correct answer ✔✔All the above
QH/QL = TH/TL, work done = QL(TH/TL -1) (t/f) - correct answer ✔✔true
carnot efficiency is different from the efficiency of the ericsson cycle (t/f) - correct answer
✔✔true
for a steam rankine cycle, thermal efficiency increases as the area under the T's curve increases
(t/f) - correct answer ✔✔true
Energy balance for cascade refrigeration... - correct answer ✔✔ma(h5-h8) = mb(h2-h3)
what happens in process 2-3 of the carnot cycle - correct answer ✔✔delta S = 0
Why is the carnot cycle not practical in refrigeration - correct answer ✔✔compressor cannot
handle liquid - vapor mixture
The compression ratio in a cylinder BEFORE the combustion process such as the diesel cycle
between P3 and P4 (t/f) - correct answer ✔✔false
, If it asks you a question about the ideal vapor compression cycle and it asks about h3 and h4 are
the same enthalpies (t/f) - correct answer ✔✔true - this is when throttling happens
the actual steam cycle has a higher efficiency than a simple rankine cycle (t/f) - correct answer
✔✔false - actual will always have less efficiency than simple/ideal
the back work ratio indicates that higher the ratio, higher the net work output and higher the
efficiency of the cycle (t/f) - correct answer ✔✔false - high back work ratio is badddd
for the otto cycle, thermal efficiency and compression ratio is linearly related so when the
compression ratio increases so does the thermal efficiency (t/f) - correct answer ✔✔False - otto
not linear
for a refrigeration cycle from stage 1-2 compression leads to the temperature rising above its
surroundings (t/f) - correct answer ✔✔true - heat is initially being absorbed to be rejected in a
later step
during the rankine cycle reheat the pressure at 4-5 is the same at 2-3 (t/f) - correct answer
✔✔false
the purpose of regeneration - correct answer ✔✔store energy temporarily and to be reused in
the cycle
COP of heat pump is 2.5 so the COP of refrigeration is 3.5 (t/f) - correct answer ✔✔false
(COP(heat pump) = 1 + COP(refrigerator) => 2.5=1+3.5 NO)
which of the following is true - correct answer ✔✔heat addition to a turbine increases efficiency
answers rated A+
for a refrigeration cycle, what must be true? - correct answer ✔✔Qout,net = Win,net
The conversation of entropy applies to a car engine (t/f) - correct answer ✔✔false
what is considered a conceivable cycle - correct answer ✔✔All the above
QH/QL = TH/TL, work done = QL(TH/TL -1) (t/f) - correct answer ✔✔true
carnot efficiency is different from the efficiency of the ericsson cycle (t/f) - correct answer
✔✔true
for a steam rankine cycle, thermal efficiency increases as the area under the T's curve increases
(t/f) - correct answer ✔✔true
Energy balance for cascade refrigeration... - correct answer ✔✔ma(h5-h8) = mb(h2-h3)
what happens in process 2-3 of the carnot cycle - correct answer ✔✔delta S = 0
Why is the carnot cycle not practical in refrigeration - correct answer ✔✔compressor cannot
handle liquid - vapor mixture
The compression ratio in a cylinder BEFORE the combustion process such as the diesel cycle
between P3 and P4 (t/f) - correct answer ✔✔false
, If it asks you a question about the ideal vapor compression cycle and it asks about h3 and h4 are
the same enthalpies (t/f) - correct answer ✔✔true - this is when throttling happens
the actual steam cycle has a higher efficiency than a simple rankine cycle (t/f) - correct answer
✔✔false - actual will always have less efficiency than simple/ideal
the back work ratio indicates that higher the ratio, higher the net work output and higher the
efficiency of the cycle (t/f) - correct answer ✔✔false - high back work ratio is badddd
for the otto cycle, thermal efficiency and compression ratio is linearly related so when the
compression ratio increases so does the thermal efficiency (t/f) - correct answer ✔✔False - otto
not linear
for a refrigeration cycle from stage 1-2 compression leads to the temperature rising above its
surroundings (t/f) - correct answer ✔✔true - heat is initially being absorbed to be rejected in a
later step
during the rankine cycle reheat the pressure at 4-5 is the same at 2-3 (t/f) - correct answer
✔✔false
the purpose of regeneration - correct answer ✔✔store energy temporarily and to be reused in
the cycle
COP of heat pump is 2.5 so the COP of refrigeration is 3.5 (t/f) - correct answer ✔✔false
(COP(heat pump) = 1 + COP(refrigerator) => 2.5=1+3.5 NO)
which of the following is true - correct answer ✔✔heat addition to a turbine increases efficiency
