Latent capacity

[ChaseAir]

Is latent capability generally reduced with larger evaporators? I have a multi split mini split system with three evaporators that has 180% larger evaporator size. Does thid kill the latent capability?

[chuckcrj]

Do you mean the indoor unit BTU ratings are 180% of the outdoor unit capacity? This is not usually allowed.

Do you have model numbers of the indoor and outdoor units?

Mini splits usually run very cold coils and have superior latent capacity.

[ChaseAir]

Do you mean the indoor unit BTU ratings are 180% of the outdoor unit capacity? This is not usually allowed.

Do you have model numbers of the indoor and outdoor units?

Mini splits usually run very cold coils and have superior latent capacity.

The strange thing is the manual says you can do it, but it all makes sense now. As rated, this mini split system has a 15% latent capacity. That is not superior to many regular split systems that have 27% latent capacity.


Hooked up my old system again today. The moisture is pouring out.

[MechAcc]

Floral cases have larger evaporators to cool the air faster to keep the humidity levels high.

[chuckcrj]

I think he is talking about mini splits.

[Bebe]

At a range of ambient conditions, typified by high wet-bulb temperature or high relative humidity with moderate temperature, the latent cooling load will be greater than 30% of the total cooling load. This often leads to inadequate dehumidification, requiring overcooling of the conditioned space or use of hot gas reheat, both inefficient practices, or compromised indoor humidity control and indoor air quality.

[hvacpope]

At a range of ambient conditions, typified by high wet-bulb temperature or high relative humidity with moderate temperature, the latent cooling load will be greater than 30% of the total cooling load. This often leads to inadequate dehumidification, requiring overcooling of the conditioned space or use of hot gas reheat, both inefficient practices, or compromised indoor humidity control and indoor air quality.

from the school of cut and paste

[Bebe]

from the school of cut and paste

yeap...
hey, not my game, still learning here, give me same time... Luckly, Darrel U is a GREAT teacher!

[ascj]

Is latent capability generally reduced with larger evaporators? YES.I have a multi split mini split system with three evaporators that has 180% larger evaporator size. Does thid kill the latent capability?Doesn't kill it, but does greatly reduce it.

I would see if your setup in a match. If it is, then there should be some published S/T ratings.

[hvacpope]

I think the evap. coil dimensions alone will not affect the sensible to latent ratios if its capacity match the load, a larger coil with more fins per inch will dehumidify better cause the large surface for condensation to take place, besides the coil area there are many other factors playing a role in latent heat removal like air velocity,coil temperature and run time.

[chuckcrj]

Make and model?

[ChaseAir]

Make and model?

Cmh1972a
2 7700 btu kmhs7720 and
1 18000 btu kmhs1872

Swear I read somewhere in the tech data you could do this, did not think about what this would do to the latent capacity. In Florida latent capacity is real important.

[chuckcrj]

According to Sanyo they say up to 24,830 btu max indoor units capacity for the CMH1972A outdoor unit.

Edit: just saw another pdf that said you're OK with up to 200% of outdoor capacity, so you're probably OK.