A compressor receives 0.1 kg/s R-134a at 150 kPa, -10 degrees C and delivers it at...

A compressor receives 0.1 kg/s R-134a at 150 kPa, -10 degrees C and delivers it at 1000 kPa, 40oC. The power input is measured to be 3 kW. The compressor has heat transfer to air at 100 kPa coming in at 20 degrees C and leaving at 25 degrees C.

I'm trying to find the mass flow rate of air, BUT can you please just show me the energy balance and Schematic to set this up. JUST the energy balance and Schematic.

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Expert Solution

Assumptions:

Compressor has constant volume and is at steady state conditions.
Single inlet and exit flow. Hence continuity equation is applicable.
Kinetic and potential energy are negligible

Continuity Equation is --- Equation 1

where are mass flowrates of R-134a at inlet and outlet respectively.

The balance for this system is

where is mass flowrate of air

h₁ and h₂ is the Enthalpy of R-134a at inlet and outlet respectively

h₃ and h₄ is the Enthalpy of air at inlet and outlet respectively.

W_in is the Power Input

Assuming air to be an ideal gas and has constant heat capacity, C_p, we get

h₄-h₃= C_p (T₄-T₃) -- Equation 2

where T₃ and T₄ is Temperature of air at inlet and outlet respectively

According to Equations 1 and 2, the balance becomes

Amanda K answered 1 year ago

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