Two-Stage Ammonia (R-717) Refrigeration Calculator

Optimize intermediate saturation pressure (P_i = √(P_e · P_c)), flash economizer subcooling, and booster/high-stage compressor mass flow and COP.

Operating Temperatures & Capacity

Low-Stage Evaporating Temp T_e (°F): -30°F ≈ 13.9 psia (deep freeze)

High-Stage Condensing Temp T_c (°F): 95°F ≈ 196 psia (evaporative condenser)

Refrigeration Load (TR - Tons): 1 TR = 12,000 BTU/hr (3.517 kW)

Compressor Isentropic Efficiency η_is:

Intercooler System Type:

Low-Stage Suction Superheat (°F):

Two-Stage Performance Results

System Coefficient of Performance (COP):

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Total Compressor Power:

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Optimal Intermediate Pressure (P_i):

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Intermediate Saturation Temp:

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Low-Stage / High-Stage Pressure Ratios:

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Power Savings vs Single-Stage:

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Two-Stage Ammonia (R-717) Thermodynamics

For low-temperature industrial freezing applications below $-15^circ ext{F}$ (blast freezers, cold storage), single-stage ammonia compression results in excessive pressure ratios ($> 8:1$), driving compressor discharge temperatures above $275^circ ext{F} - 300^circ ext{F}$ and breaking down lubricating oil.

Equal Pressure Ratio Principle

P_intermediate = √(P_evaporator · P_condenser)

Balancing the pressure ratios across the low-stage booster and high-stage compressor minimizes total electrical shaft power, while flash intercooling desuperheats the booster vapor to saturation.

Two-Stage Ammonia (R-717) Refrigeration Calculator

Operating Temperatures & Capacity

Two-Stage Performance Results

Two-Stage Ammonia (R-717) Thermodynamics

Equal Pressure Ratio Principle

Frequently Asked Questions