Heating coil questions

[hepa99]

This is the first time I will design heating coil since most of the project I design don't need heating.

When I do cooling coil selection - I used psychrometric chart to select the coil in/out condition (computing mix air, use 55f supply air, 7c 12c chilled water entering & leaving, etc). I guess this how you do in selecting heating coil selection except the supply air is roughly at 100f...is there any special computation I need to know for mix Air (or its the same computation as with cooling coil)?....what's the normal or recommended hot water in/out temp?

Also are you guys using psychrometric too when you do heating? In cooling I used psych chart a lot.

 

[MintJulep]

There are some simplified equations since it's a sensible only process.

However since you have mixed metric and imperial units I'm not going to attempt to work them out.

If you're comfortable working with a psychrometric chart for cooling go right ahead and use it for heating too. Everything works the same.

 

[houseman20]

If your heating is from overhead, I don't recommend exceeding 85F, due to buoyancy. ASHRAE 62 will penalize if you exceed 85F, with overhead heating. Hot water traditionally uses 180F supply temperatures with delta T of 20/30/40. With Condensing boilers, you may want to use as low of a return temperature as possible, in that case, your coil approach temperature could be anywhere between 8F and 80F. It may be a tradeoff between approach temperature/boiler efficiency and coil air pressure drop.

 

[chicopee]

Is you post for comfort heating or process heating?

 

[xpsboy]

How to get the steam data (inlet pressure & lbs/hr) for heating coil?
Thanks