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Hey Ed, What Is This Change in Enthalpy Malarkey You Were Mumbling About?


In This Edition of “Hey Ed,” Ed Discusses What the Change in Enthalpy Malarkey He Was Mumbling About

Hey Ed, what is this change in enthalpy malarkey you were mumbling about? I've had more than 17 people in my day ask me that particular question. Enthalpy is nothing more than a way to quantify how much heat and when I say heat, we're talking about both sensible and latent heat is in a pound of air. It is a very good representation of how much heat a pound of air contains. Well, we can take some measurements. Generally, we talk about volumes of air in CFM and it's not that difficult to turn that into a pound of air measurement and if we know a pound of air has a difference in enthalpy supply and return numbers which are obtained by taking a wet bulb temperature with those wet bulb temperatures we can determine what our change in enthalpy is and with a little bit of math we can determine how many B to use a piece of equipment is removing now typically this is going to be an air conditioning process. Can it be heat? Sure but it's really geared or focused more on the cooling capacity of an air conditioning system and it's a great way to determine if a piece of equipment has the potential of doing what it's supposed to as opposed to simply taking a couple of sensible temperatures which I'm not in favor of and that's the way I see it.

In This Edition of “Hey Ed,” Ed Discusses What the Change in Enthalpy Malarkey He Was Mumbling About

Ed Janowiak is the Manager of HVAC Design Education at ACCA.


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Posted In: Hey Ed, Technical Tips

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