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Compressor Sizing Calculator

Polytropic and isentropic compression power calculation with gas properties, discharge temperatures, and shaft power for centrifugal and reciprocating compressors

Gas

Operating Conditions

Efficiencies

Results

Gas

Air

Gas Constant R

287.1000J/kg·K

Specific Heat cₚ

1,005J/kg·K

Ratio γ = cₚ/cᵥ

1.400

Inlet Density

1.1834kg/m³

Volumetric Flow

1,000m³/h

Mass Flow

0.328730kg/s

Pressure Ratio

4.94

Poly. Exponent n

1.556

Polytropic Eff.

80.0%

Discharge Temperature

Isentropic T₂

197.3°C

Polytropic T₂

254.2°C

Actual T₂

240.4°C

T₂ Rise ΔT

215.4°C

Power

Isentropic Power

56.9320kW

Polytropic Power

60.5569kW

Shaft Power

62.4298kW

Mech. Eff.

97.0%

Polytropic Eff: Good (80%)
Discharge T: High (240°C) — consider intercooling
Pressure Ratio: Multi-stage required (4.9)

Centrifugal Compressors

  • Continuous flow, high capacity
  • Typical polytropic efficiency: 70–85%
  • Best for steady, large volume applications
  • Multiple stages for high compression ratios

Reciprocating Compressors

  • Positive displacement, high pressure
  • Typical polytropic efficiency: 75–90%
  • Best for high pressure, lower volume
  • Intercooling between stages