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Which one of the following is correct relation between (COP)HP and (COP)R
  • a)
    (COP)HP – (COP)R = 1
  • b)
    (COP)R – (COP)HP = 1
  • c)
    (COP)HP + (COP)R = 1
  • d)
    (COP)HP + (COP)R = 0
Correct answer is option 'A'. Can you explain this answer?
Most Upvoted Answer
Which one of the following is correct relation between (COP)HP and (CO...
The efficiencyof a refrigerator is expressed in terms of the coefficient of performance (COP), denoted by COPR. The objective of a refrigerator is to remove heat (QL) from the refrigerated space. To accomplish this objective, it requires a work input of Wnet,in. Then the COP of a refrigerator can be expressed as

COPR=(desiredoutput)/(requiredinput)=Q(L)/W(net,in)        ---(1)
 
This relation can also be expressed in rate form by replacing QL by QL and Wnet, in by W(net,in).

The conservation of energy principle for a cyclic device requires that

W(net,in)=QH−QL(KJ)  ----(2)

Then the COP relation becomes

COPR=QL/(QH−QL)=1/(QH/QL−1)    ----(3)

Notice that the value of COPR can be greater than unity.

Another device that transfers heat from a low-temperature medium to a high temperature one is the heat pump. Refrigerators and heat pumps operate on the same cycle but differ in their objectives. The objective of a heat pump, however, is to maintain a heated space at a high temperature. This is accomplished by absorbing heat from a low temperature source, such as well water or cold outside air in winter, and supplying this heat to the high-temperature medium such as a house.

The measure of performance of a heat pump is also expressed in terms of the coefficient of performance COP_HP, defined as

COP(HP) = (Desiredoutput)/(Requiredinput)=QH/W(net,in)     --(4)

This can also be expressed as,

COP(HP) = QH/(QH−QL) = 1(1−(QL/QH))  --(5)
Comparing equation 3 and 5 reveals that,

COP(HP) = COP(R) + 1
(COP)HP – (COP)R = 1


for fixed values of QL and QH. This relation implies that the coefficient of performance of a heat pump is always greater than unity since COPR is a positive quantity. government policy or in trade arrangements, and by development of irrigation, roads, and other infrastructures. 
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Which one of the following is correct relation between (COP)HP and (CO...
Explanation:

To understand the correct relation between (COP)HP and (COP)R, let's first define what COP stands for.

COP stands for Coefficient of Performance, which is a measure of the efficiency of a refrigeration or heat pump system. It is defined as the ratio of the desired output to the required input.

Now let's look at the given options and analyze each one:

a) (COP)HP (COP)R = 1
This option states that the COP of a heat pump (COP)HP multiplied by the COP of a refrigeration system (COP)R is equal to 1. This relation is incorrect because the COPs of a heat pump and a refrigeration system are not inversely proportional to each other. Therefore, option 'A' is incorrect.

b) (COP)R (COP)HP = 1
This option states that the COP of a refrigeration system (COP)R multiplied by the COP of a heat pump (COP)HP is equal to 1. This relation is also incorrect for the same reason mentioned above. Therefore, option 'B' is incorrect.

c) (COP)HP (COP)R = 1
This option states that the COP of a heat pump (COP)HP multiplied by the COP of a refrigeration system (COP)R is equal to 1. This relation is incorrect for the same reason mentioned above. Therefore, option 'C' is incorrect.

d) (COP)HP (COP)R = 0
This option states that the COP of a heat pump (COP)HP multiplied by the COP of a refrigeration system (COP)R is equal to 0. This relation is also incorrect because a COP value of 0 is not physically possible. Therefore, option 'D' is incorrect.

Therefore, the correct relation between (COP)HP and (COP)R is none of the given options.
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