A heat pump is used to maintain a house at 22°C by extracting heat from the outside air on a day when the outside air temperature is 2°C. The house is estimated to lose heat at a rate of 110,000 kJ/h, and the heat pump consumes 5 kW of electrical power when running. Is this heat pump powerful enough to do the job?

Respuesta :

Answer:

It is enough

Explanation:

To develop the problem it is necessary to take into account the concepts related to the coefficient of performance of a pump.

The two ways in which the performance coefficient can be expressed are given by:

[tex]COP_p = \frac{T_H}{T_H-T_L}[/tex]

Where,

[tex]T_H =[/tex]High Temperature

[tex]T_L =[/tex] Low Temperature

And the other way is,

[tex]COP_p = \frac{\dot{Q}}{W}[/tex]

Where [tex]\dot{Q}[/tex] is heat rate and W the power consumed.

We have all our terms in Celsius, so we calculate the temperature in Kelvin

[tex]T_H = 22+273 = 295K[/tex]

[tex]T_L = 2+273 = 275k[/tex]

The rate at which heat is lost is:

[tex]\dot{Q} = 110000kJ/h[/tex]

The power consumed by the heat pump is

[tex]\dot{W} = 5kW[/tex]

And the coefficient of performance is

[tex]COP_p = \frac{T_H}{T_H-T_L}[/tex]

[tex]COP_p = \frac{295}{295-275}[/tex]

[tex]COP_p = 14.75[/tex]

With this value we can calculate the Power required,

[tex]COP_p = \frac{\dot{Q}}{W}[/tex]

[tex]14.75 = \frac{110000}{W}[/tex]

[tex]W = \frac{110000}{3600*14.75}[/tex]

[tex]W = 2.07kW[/tex]

The power consumed is consumed is 5kW which is more than 2.07kW so this heat pump powerful enough.

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