Humidification energy split — does sensible heat always decrease? Evaluate the statement: “The sensible heat during humidification decreases.” Consider general humidification methods (evaporative and steam-injection).

Introduction / Context:
Humidification raises the moisture content of air, but its effect on sensible heat (air temperature) depends on how the moisture is added. This nuance is vital when selecting humidifiers and predicting space conditions.

Given Data / Assumptions:

• Two common methods: adiabatic evaporative humidification and steam-injection humidification.
• Air pressure roughly constant; duct heat losses small.

Concept / Approach:
In adiabatic evaporative humidification, water evaporates by taking latent heat from the air stream itself. The air’s dry-bulb temperature drops (sensible heat converts to latent), so sensible heat content decreases while total enthalpy remains nearly constant. In steam injection, however, high-temperature vapor condenses/ mixes into the air, increasing both moisture content and sensible heat; the dry-bulb temperature rises. Therefore, the blanket statement that sensible heat “decreases” during humidification is not universally true.

Step-by-Step Solution:
Case 1 (evaporative): air gives up sensible energy → T_db falls → sensible heat decreases, w increases, h ≈ constant.Case 2 (steam injection): added steam brings enthalpy → T_db rises → both w and sensible heat increase.Hence the general statement is false; the effect depends on the method.

Verification / Alternative check:
Psychrometric chart paths: evaporative humidification follows nearly constant enthalpy (constant wet-bulb) to higher w and lower T_db; steam injection trends upward and to the right, raising both T_db and w.

Why Other Options Are Wrong:
(a) Overgeneralizes; true only for the adiabatic case. (c) is a conditional truth but the stem asks generally. (d) and (e) add irrelevant constraints that do not govern the sign of sensible heat change.

Common Pitfalls:
Equating “humidification” solely with evaporative coolers; many HVAC systems use steam grids specifically to raise both humidity and temperature.

Final Answer:
False