“How can we calculate the specific energy for humid air?”
Air can vary a lot in both temperature and humidity. And sometimes, we would like to know the specific energy for humid air under constant pressure at a reference temperature ignoring the effects of condensation. To do this, we can calculate by the Sigma Heat S = 17.86 (kj/kg) + 1.05 (kj/kg)*t + W(2501 (kj/kg) + 1.884(kj/kg)*t), where t is the dry-bulb temperature of the air (in °C), and W is the specific humidity of the air (no unit). The Sigma Heat equation is commonly used in mining engineering to calculate the temperature regulation of mine air.