Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning - Discussion

When the air temp is higher than the liquid so liquid absorbs that heat energy from the air and evaporates it and the liquid-dipped thermometer that records that temperature is called the wet bulb temp.

So when the sensible heat of air is increased it means the wet bulb temp is also increased.

For the same, refer to Psychrometric Chart & draw the process for sensible heating over it. You should observe various points related to DBT, WBT, Rh, Sp. humidity, enthalpy, sp. volume lines. For the drawn process 1-2, the DBT & WBT increases. As it is a heating process, the number of water particles present in the air will be removed, hence the Rh decreases. Whereas the sp. humidity remains constant. The SP volume increases from 1 to 2. As we are adding heat to the air, its temperature & internal heat increases, which in turn increases the Enthalpy of air.

Wet bulb temperature from the psychrometric chart starting from left to right is kept on increasing. Wet bulb is increase with the increase of sensible heat.

You are right, I agree @Asif Ali Shah.

DBT increase then WBT also increase humidity remains constant.

As sensible heat is done but specific humidity is constant but the air capacity to get vapor increases so air will get more moisture from cotton of wet bulb thermometer and hence cotton will absorbs more heat from mercury and hence the mercury bulb will goes down means cool down means temperature will decrease but if we see by psychometric chart and from left to right as sensible line goes is showing that wet bulb is decreasing.

Wet bulb means thermometer bulb covered with wet cloth. So, the temperature measurement depends on the wet cloth will evaporate or becoming wet. If temp increases the moisture will decrease so the wet bulb become dry (temp increases).

WBT means temperature sense by thermometer bulb is in contact with the wet cloth. Thermometer bulb is covered with wet clothes.

@Eajaz & Raj.

Wet bulb temperature is the temperature taken by similar type of thermometer but the thermometer sensor is covered with wet cloth.

In sensible heating, we are adding heat so DBT increases if DBT increases WBT also increases.