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Hey all,

I am working on a problem that goes like this:

The solutions manual calculates the mass of the air inside the truck and afterwards does

[tex]Q=mc_p\Delta T[/tex]

to calculate the amount of heat removed.

My question is: why do we use [tex]c_p[/tex] here and not [tex]c_v[/tex]

It's a closed system, such that

[tex]Q=m(u_2-u_1)=mc_v\Delta T[/tex]

right?

I am working on a problem that goes like this:

*The cargo space of a refrigerated truck whose inner*

dimensions are 12 m 3 2.3 m 3 3.5 m is to be precooled

from 25°C to an average temperature of 5°C. The construc-

tion of the truck is such that a transmission heat gain occurs

at a rate of 120 W/°C. If the ambient temperature is 25°C,

determine how long it will take for a system with a refrigera-

tion capacity of 11 kW to precool this truck.dimensions are 12 m 3 2.3 m 3 3.5 m is to be precooled

from 25°C to an average temperature of 5°C. The construc-

tion of the truck is such that a transmission heat gain occurs

at a rate of 120 W/°C. If the ambient temperature is 25°C,

determine how long it will take for a system with a refrigera-

tion capacity of 11 kW to precool this truck.

The solutions manual calculates the mass of the air inside the truck and afterwards does

[tex]Q=mc_p\Delta T[/tex]

to calculate the amount of heat removed.

My question is: why do we use [tex]c_p[/tex] here and not [tex]c_v[/tex]

It's a closed system, such that

[tex]Q=m(u_2-u_1)=mc_v\Delta T[/tex]

right?

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