There might be lots of differences, there may be none. For instance, I can increase static pressure (slowing the air) and increase heat absorption by increasinf fin area. (more fins per inch, wider fins, rippled fins) which would give me more latent capacity, but the exact same tubing arrangement with narrower fins, fewer fins per inch, smooth fins, will have more sensible capacity.
Or, take the exact same coil, but one has a piston, and one has a TXV. Or, both have TXVs, but one is set for 6� superheat, and one is set for 15� superheat. (lower superheat means colder coil, menaing more latenet capacity.
Here are the results of the test I promised:
A 25 ton RTU, in a psychrometric room, running 8000 indoor CFMs and 10,000 outdoor CFMs. The indoor dry bulb is 80�, the outdoor drybulb is 95�. The only variable is the indoor wetbulb (noted on chart).
(Wet Bulb Temp)(Total Capacity)(Sensible) (Latent) (EER)
(67) 310474.9 BTUH 207707.7 102767) (10.23)
(65) 297247.7 225611 71636.7) (9.83)
(63) 287816.5 242629.31 45187.2) (9.53)
(61) 283486.5 261374.6 22111.9) (9.5)
(59) 282045.5 269071.41 12974.1) (9.46)
As you see, like we first assumed, some of the latent capacity moves into the sensible column, but some of the capacity just disappears. These are TXV systems, so the superheat remained unchanged. But, in theory, if you tried this with a fixed orifice metering device, the superheat would drop off and the system would start to flood back.
Hopefully, this will help illuminate some of the discussion that has taken place here.
Man! Tables don't do too well ni here do they? Sorry for the smilie faces, but they are to divide the data columns.
[Edited by BamaCracker on 03-21-2002 at 09:24 PM]
There are no stupid questions. . .just a lot of inquisitive idiots.