Airconditioning settings or tolerances + 35oC D.B. / + 30oC W.B. what does it mean?

Question

I am translating an air conditioning technical manual and I have found two abbreviations that I dont understand the meaning of, can anyone help me?

+ 35oC D.B. / + 30oC W.B. What do D.B. and W.B. stand for??

Answer 1

+35 degress Celcius (+35oC D.B=Dry Bulb, W.B. = Wet Bulb)

Basically, its saying that there will generally be a 5 degree celcius difference if the Bulb is Dry as apposed to Wet. The bulb is the name of the instrument used to determine the ammount of Humidity (moisture) in the air, which effects the ammount of work required by the A/C to compensate for. See the link below for a more detailed explaination.

Answer 2

The answer is 35 degrees Dry Bulb, and 30 degrees Wet Bulb. The measure of dry bulb is the measure of air without any moisture in it. The wet bulb is the measure of the air concidering the energy of moisture in it. Moisture is air is in the form of steam. Steam has energy to keep it in that form (as opposed to liquid). So when you take into accout the temperature of the air with steam mixed in it, you are accounting for moisture. The wet bulb temperature is also measured as the "Dew Point" temperature. Without a class in psycheometrics, dew point is the temperature of the air where water condenses.

The reason for giving the temperature in this format is that engineers use a chart called a "Mollier Diagram" or "Psycheometric Chart" to plot those two points on it. It's like playing battleship where the dry bulb would be the numbers and the web bulb would be the letters. Once they plot the point on the chart, they then can tell exactly how much moisture is exactly in the air (measured in grains) and also determine the relative humidity of the air.

In order to obtain the two different temperatures (wet bulb vs. dry bulb) you need two different devices. You use a standard thermometer for the dry bulb, and you use something called a "Sling Psychrometer" for the wet bulb.