what is enthalpy? 1

[manubose]

hi,
guys please told me what is enthalpy?

regards
manubose

 

[IRstuff]

Is your Wikipedia broken?

http://en.wikipedia.org/wiki/Enthalpy

TTFN
faq731-376

 

[KiwiMace]

It is energy.

It is the kind of energy stored by a compressible fluid.

It is the sum of the energy it had when it was just sitting there, and the energy it obtained when you did work on it.

Thus, it is the type of energy most useful to an engineer studying a system that has air, steam, water vapour, R-134a etc as the working fluid.

 

[willard3]

Rather than using Wiki to learn thermodynamics, take a course in thermodynamics.

Its units are btu/lbm.

 

[chicopee]

Here is a short course on thermo h=u+pv

 

[IRstuff]

gee, that looks familiar:

http://en.wikipedia.org/wiki/Enthalpy#Formal_definition

TTFN
faq731-376

 

[317069]

It is Entropy's sister, don't ask what is Entropy because i don't know.

 

[chicopee]

Except my formula is in lower case having a unit of btu/lbm.

 

[sspeare]

I agree with williard3. You need to take a course in Thermodynamics. That's what engineers do: they study the topic. How absurd: to think you can learn about Thermo from Wikipedia!

 

[Ranajees]

For first hand information Wikipedia is good, for detailed study one has to look for some course. Some jokes are nice above. thanks.

 

[EPullin]

Refer to the ASHRAE Handbook 2009 - Fundamentals or CIBSE Guide C - Reference Data for clarification.

For the metric minded among us, specific enthalpy has units of kJ/kg

 

[Shophound]

Nutshell definition of enthalpy = "heat content".

In HVAC/R work we are interested in enthalpy in terms of sensible and latent heat content in a given quantity of air. The common IP metric for this is btu/lb of dry air. A psychrometric chart will have enthalpy info in either this or SI form.

 

[rmw]

Not meaning to be rude, but if you come on a site like this one for engineering professionals and ask a question like that, I'm not sure you could understand the answers. I'm not meaning to be arrogant, but just stating the facts. We are worlds apart here. Answering it to you would be like trying to explain it to someone at church. Now that would be hard.

rmw