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


The wet bulb temperature during sensible heating of air

[A]. remains constant
[B]. increases
[C]. decreases

Answer: Option B


No answer description available for this question.

Jayakrishna said: (Mar 20, 2013)  
DBT increases in sensible heating while DBT temp increases WBT increases.

Akshay said: (Mar 20, 2013)  
On Psychometric chart Dry Bulb temp. Increases from left to right. During sensible heating process specific humidity remains constant (i.e. process is showed by horizontal line). So as we move from left to right WBT lines (inclined lines) increases from Bottom left corner to upper right corner. So we can clearly say that WBT increases. Description can easily understood by Psychometric chart.

Prathamesh Sawant said: (Jun 19, 2013)  
If you observe your psychrometric chart, you will observe that the enthalpy and WBT line travel proportionally. In sensible heating the path of process is along the +ve y-axis. Thus you will observe that the three lines of enthalpy, heating and WBT are proportional to each other. Hence.

Venkatesh Slm said: (Dec 4, 2013)  
It states that specific humidity constant and there was a change (increase & decrease) in wet bulb temperature in sensible process. (heating & cooling).

Er A.K. Rajput said: (Aug 26, 2014)  
DBT increase then WBT also increase humidity remains constant.

Vignesh said: (Oct 27, 2014)  
In latent heating the temperatures remains constant the phases will be changed. But sensible heating the temperature will increased further. So that the wet bulb temperature is increased.

Ch.Ramanadham said: (Nov 1, 2014)  
Wet bulb temperature means environmental temperature when the increasing of air temperature then automatically the wet bulb temperature also increased.

Mohan said: (Nov 4, 2014)  
When the sensible of heat of the air increases, the wet bulb temperature decrease down. Because, the moisture in the air expands.

Bipin Yadav said: (Nov 19, 2014)  
As we know heat flow from higher temperature. To lower temperature so wet bulb will dry means the temperature of wet bulb will increase due to the temperature of air.

Sohel said: (May 30, 2015)  
As sensible heating is done of air the temp. Will increase & thus the temp. Of wet bulb is also increased.

Shubham Sharma said: (Jul 22, 2015)  
Since we are heating sensibly so the temperature of air get up then the moisture it taking from bulb increases which in affect increase the temperature.

Ejaz said: (Oct 26, 2015)  
Wet bulb means please tell me?

Indu said: (Oct 27, 2015)  
As the sensible temperature of air increases wet bulb temperature also increases.

Ayyappa said: (Oct 27, 2015)  
Adding heat increases both DBT and WBT.

Suresh said: (Dec 11, 2015)  
During sensible heating there is no phase change takes place only temp increase.

Atif said: (Jul 11, 2016)  
Dry bulb thermometer measures simply the temperature of the air and wet bulb thermometer measures the temperature of saturated air means with 100 percent humidity at that specific temperature if we increase the temperature of air means a number of vapors that an air can store also increases.

Rajkumar said: (Aug 23, 2016)  
What is the WBT? Please explain it.

U.Gururaj said: (Aug 29, 2016)  
Dry bulb thermometer measures simply the temperature of the air and wet bulb thermometer measures the temperature of saturated air means with 120 percent humidity at that specific temperature.

Divy said: (Dec 16, 2016)  
If specific humidity increase then dehumidification is done then what will occur?

Lakshman said: (Mar 13, 2017)  
Why using the hair of horse at humidistat. And function?

Dinesh said: (May 6, 2017)  
In sensible heating, we are adding heat so DBT increases if DBT increases WBT also increases.

Dev said: (Jun 19, 2017)  
@Eajaz & Raj.

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

Prashant S. Bulbule said: (Jul 19, 2017)  
WBT means temperature sense by thermometer bulb is in contact with the wet cloth. Thermometer bulb is covered with wet clothes.

Veniston said: (Jun 7, 2018)  
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).

Asif Ali Shah said: (Dec 20, 2018)  
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.

Ajay said: (Jan 2, 2019)  
DBT increase then WBT also increase humidity remains constant.

Shahidraza said: (Jun 18, 2019)  
You are right, I agree @Asif Ali Shah.

Babagana Jidda Shettima said: (Aug 19, 2019)  
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.

Npj said: (Apr 19, 2021)  
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.

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