The coefficient of performance (COP) of refrigeration is
always more than 1
. Hence option (a) is correct. COP is the ratio of heat extracted from the refrigerator to the work done on the refrigerant. Thus it is but obvious that the value of COP is bound to be greater than unity since efficiency is always less than 1.
What is the best coefficient of performance for a refrigerator?
For a refrigerator keeping an inside temperature of 4
o
C = 277 K operating in a room at 22
o
C = 299 K the best possible coefficient of performance is
COP
max
= 277/(299 – 277) = 12.6
. The best possible ratio of the amount of heat removed to the work done is 12.6.
Why is the COP of a refrigerator greater than one?
Why the value of the COP of the refrigeration system is always greater than 1? The COP usually exceeds 1, especially in heat pumps, because, instead of just converting work to heat (which, if 100% efficient, would be a COP of 1),
it pumps additional heat from a heat source to where the heat is required
.
Can COP HP be lower than unity?
COP less than 1 is almost “unheard of”..but
yes it is possible to have COP less than 1
. Even though VARS has COP less than 1 ;it is still an energy efficient system because VARS uses low grade thermal energy as the energy input which can be waste heat from gas turbines ,geothermal energy etc.
Why coefficient of performance COP of a refrigerator is more during winter than summer?
Why is COP of Carnot refrigerator in winter higher than the COP in summer? According to the equation of COP,
if temperature cooling water or available heat rejection is low, the COP will be high
. In winter season the temperature of cooling water T
2
is low, so the COP will be higher.
Is a higher or lower COP better?
The coefficient of performance or COP (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work (energy) required.
Higher COPs equate to higher efficiency, lower energy
(power) consumption and thus lower operating costs.
What is COP formula?
COP =
|Q| W
. COP is defined as the relationship between the power (kW) that is drawn out of the heat pump as cooling or heat, and the power (kW) that is supplied to the compressor.
Is a high COP good or bad?
Air source heat pumps tend to be less efficient, and
a COP over 3 is considered good
. Comparing different air source heat pumps, it is worth bearing in mind that a heat pump with a higher CoP / SPF will cost more, and the same is true when comparing ground source heat pumps with one another.
Can the COP be greater than unity?
The pragmatic definition of the COP is: COP = (What you Get)/(What you Pay For). This
measure of performance can have a value greater than unity
, and it is this fact that makes a heat pump an attractive device.
What is COP Carnot?
The
coefficient of performance of
the Carnot cycle is: COP Carnot cycle = T L T H − T L = 258 313 − 258 = 4.69. Thus, the relative coefficient of performance is defined by: COP relative = Actual coefficient of performance Theoretical coefficient of performance = 4.53 4.69 = 0.97.
What is the relative coefficient of performance?
Relative coefficient of performance defined as
the ratio of actual C.O.P. to the theoretical C.O.P. Relative C.O.P. = Actual C.O.P./Theoretical C.O.P.
Where does the lowest temperature occur in a refrigerator?
- Evaporator.
- Expansion valve.
- Condenser.
- Compressor.
How do you improve the COP?
To improve the coefficient of performance, its requires that the
compressor work should decrease and refrigeration effect should increase
. It means that decrease in condenser pressure and temperature so the refrigeration effect will increase and compressor input work due to this cop will increase.
What is a good COP value?
That means that in 100% ideal case the
maximum COP is 8.8
. But in practice, it’s lower. In fact, the highest COP a heat pump can achieve is about 4.5. Any heat pump with a COP of above 3 has a very high energy-efficiency.
Can the COP of a refrigerator be greater than 1?
COP is the ratio of refrigeration effect and work done. … Technically COP has been designed for vapour compression cycle and it is
alwats greater than 1
. because if it is less than 1 than the efficiency will become more than 1, which impractical.
What is a good coefficient of performance?
Test results of the best systems are
around 4.5
. When measuring installed units over a whole season and accounting for the energy needed to pump water through the piping systems, seasonal COP’s for heating are around 3.5 or less. This indicates room for further improvement.
