h,x Chart Coil Measurement

Data center air handler with DX evaporator or chilled water coil, evaluated from air-side and refrigerant or water-side measurements

Sample values, replace with your own measurements
Mollier h,x chart · p = 1013 hPaHover over the chart to read a state
Coil process 1 → 2 Extension to saturation (apparatus dew point K) Evaporating temperature t₀ Saturation φ = 100 %
1 · Air entering coil
2 · Air leaving coil
Refrigerant circuit (evaporator)
Boundary conditions

Air states

Quantity1 in2 out

Coil & cooling circuit

Assessment

    Method: saturation pressure from the Magnus formula (over water, below 0 °C over ice), enthalpy h = 1.006·t + x·(2501 + 1.86·t), oblique Mollier coordinate system. Chilled water capacity Q = V·ρ·cp·(treturn − tsupply) with properties at about 10 °C (water 4.19 kJ/kgK, ethylene glycol 30 % 3.70 kJ/kgK, propylene glycol 30 % 3.88 kJ/kgK). Refrigerant saturation temperatures (dew line) from CoolProp points every 2.5 K, interpolated, accuracy about ±0.1 K. The apparatus dew point K is where the extended process line meets the saturation curve, i.e. the effective mean surface temperature of the coil.