GPSA Ch. 14
| Parameter | Range |
|---|---|
| Gas Inlet Temp | 80–120°F |
| Gas Outlet Temp | −20–40°F |
| Approach Temp | 5–15°F |
| U-value (S&T) | 50–150 BTU/hr-ft²-°F |
| Fouling Factor | 0.001–0.003 hr-ft²-°F/BTU |
Heat Duty:
Where Q = heat duty (BTU/hr), m = gas mass flow rate (lb/hr), Cp = gas specific heat (BTU/lb-°F), Tin = gas inlet temperature, Tout = gas outlet temperature.
Heat Transfer Area:
Where A = required heat transfer area (ft²), U = overall heat transfer coefficient (BTU/hr-ft²-°F), LMTD = log-mean temperature difference (°F), Ft = LMTD correction factor for multi-pass exchangers.
Log-Mean Temperature Difference:
For shell-side boiling refrigerant at constant temperature: ΔT1 = Tgas,in − Trefrig and ΔT2 = Tgas,out − Trefrig.
Refrigerant Flow: Determined from heat duty divided by the latent heat of vaporization of the selected refrigerant at operating pressure. Propane is the most common refrigerant in midstream gas processing.
Understand gas chiller design, refrigerant selection, and LMTD calculations for refrigeration service
The calculator determines required heat transfer area using Q = U × A × LMTD, where Q is the heat duty, U is the overall heat transfer coefficient, and LMTD is the log-mean temperature difference per GPSA Ch. 14.
The calculator supports propane, ethane, propylene, ammonia, and R-22 refrigerant systems. Each refrigerant has specific latent heat and boiling point data used to calculate refrigerant flow rate and chiller performance.
Approach temperature is the difference between the process gas outlet temperature and the refrigerant evaporating temperature. Smaller approach temperatures require more heat transfer area but improve thermodynamic efficiency.
Overall heat transfer coefficients for gas chillers in refrigeration service vary with refrigerant and fouling conditions. The calculator allows user-specified U-values or estimates based on GPSA Ch. 14 and TEMA standards.