Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.
calculating btu capacity of an evaporator
zepfan
Member Posts: 403
does anyone know how to calculate the btu capacity of a dx evaporator coil? i know it has to do with taking a delta t reading across the coil, and some wet bulb readings but have yet to get the full, correct calculation
0
Comments
-
Here you go
In order to determine what the evaporator coil is doing at a particular time, you will need to know both the sensible and latent activity of the coil.
You can do this a number of ways.
You will need any two of the following pieces of information for both the supply and return air:
Dry bulb temperature, wet-bulb temperature, relative humidity. You will also need an accurate cfm value.
These values need to be obtained just before and just after the evaporator coil, not at the supply registers and return grills!
You will also need a psychrometric chart, on which you will plot the supply and return air points.
Once done, you can determine the enthalpy (heat content) of the supply and return air and then calculate the difference.
With all of these goodies in hand, plug those values into:
Qtotal = 4.5 x cfm x change in enthalpy
This will give you the evaporator capacity at that point in time (snapshot).
The 4.5 is simply a constant that changes the minute in cfm to the hour in Btuh, as well as accounts for the conversion between air volume (cubic feet) and the weight of air.
I hope this helps....
Have fun and let us know how you make out.There was an error rendering this rich post.
0 -
thank you
thanks for the reponse.i'll let you know0
This discussion has been closed.
Categories
- All Categories
- 86K THE MAIN WALL
- 3.1K A-C, Heat Pumps & Refrigeration
- 52 Biomass
- 420 Carbon Monoxide Awareness
- 80 Chimneys & Flues
- 1.9K Domestic Hot Water
- 5.3K Gas Heating
- 96 Geothermal
- 154 Indoor-Air Quality
- 3.3K Oil Heating
- 60 Pipe Deterioration
- 891 Plumbing
- 5.9K Radiant Heating
- 378 Solar
- 14.7K Strictly Steam
- 3.2K Thermostats and Controls
- 52 Water Quality
- 41 Industry Classes
- 47 Job Opportunities
- 17 Recall Announcements