Cooling Capacity

[iceman007]

I am wondering how to calculate kW output from an air conditioning system by using the running data. I think that perhaps I may need to use a PT chart or similar. By using superheat, subcooling, air temps etc, is there a way to calculate how many btus/kW are being ouptput ?

Thanks

[nike123]

Each capacity of an air conditioner can be obtained by following calculations and by measuring the temperatures of the suction and discharge air temperatures of heat exchanger with thermometer and applying psychometrics chart.
Terms:
Qcool Cooling capacity (kcal/h)
Qheat Heating capacity (kcal/h)
Qdry Drying capacity (kcal/h)
i1 Enthalpy of suction air (kcal/kg)
i2 Enthalpy of discharge air (kcal/kg)
x1 Absolute humidity of suction air (kg/kg)
x2 Absolute humidity of discharge air (kg/kg)
t1 Temperature of suction air (°C)
t2 Temperature of discharge air (°C)
u2 Specific volume of discharged air (m3/kg)
V Air flow rate of measured heat exchanger (m3/h)

Formulas:
http://farm3.static.flickr.com/2126/2241884606_bde4e9b887_o_d.jpg

[0,24= Specific heat of dry air (kcal/kg°C)]

[iceman007]

Thank You.

[expat]

You might want to look at this tool/toy.
http://www.hvactool.com/catalog.php3?hcategory=&hsubcat=&hpagenum=1&hproductid=TIFVA500A&haction=search&fsearch=hvac%20analyzer

It looks handy but I wonder why I would need to make such a measurement other than to prove to a customer that their equipment is doing what it is designed to.

I suppose you could use it get a quick reading of the systems perfomance then put this information on your yearly service sheet.