Dehumidification with DX Split
Dehumidification with DX Split
(OP)
I'm trying to control humidity in a space using a conventional 5 ton DX split system. The system will have an electric heating coil and a wall mounted thermostat.
My question is, will dehumidification be possible? Do they make a thermostat that has a dehumidification cycle built in?
My question is, will dehumidification be possible? Do they make a thermostat that has a dehumidification cycle built in?





RE: Dehumidification with DX Split
Control of humidity is not possible with a DX conventional split system.
RE: Dehumidification with DX Split
RE: Dehumidification with DX Split
I assume that in your case you have a máximum level of relative humidity that can not be passed.
Basically it depends on the rate of water vapor generation in the space. The latent load capacity of the DX system is limited, so in certain cases you will not be able to dehumidify.
Maybe it will be good to provide more info on the use of the space and why they want to control humidity.
RE: Dehumidification with DX Split
The space is not a latent load generating space. It's just a parts assembly 2000 sf space with about 6 people in it.
RE: Dehumidification with DX Split
RE: Dehumidification with DX Split
Therm being the root for heat, that is to say temperature.
If you want to actively control cooling and reheat to maintain a specific space RH then you need to measure RH and act accordingly.
RE: Dehumidification with DX Split
Basys makes a line of thermostats that can be configured to maintain humidity as well as sensible heat that have a broad selection of outputs for the devices you need. You may want to consider using a Sporlan Electronic Hot Gas Bypass valve to modulate the hot gas feature based on an output from the Basys device.
I have done this as well as an EXV based on the actual load requirements.
For the condensing side, look at Danfoss and their VFD and related compressors. These compressors can deliver service from 30 Hz to 90Hz to help maintain your specifications.
RE: Dehumidification with DX Split
Choose carefully. First, read all the specs. Second, download the manuals for the ones that pique your interest and and read them. Third, sketch how you'll apply the one you think is best. Fourth, purchase one.
Best to you,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies
RE: Dehumidification with DX Split
There are these too. and many others if you put this in Google: humidistat
Disclosure: I consult with Kele
Best to you,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies
RE: Dehumidification with DX Split
need to figure what your sensible cooling load and latent cooling load will be. And size the unit accordingly.
make sure your looking at two stage compressors or variable-speed compressor and fan.
there are companies who make units to control Humidity.
RE: Dehumidification with DX Split
I understand that I won't be able to control the humidity down to a narrow window, but I think what I have specified will get us in the range as long as the latent and sensible loads are satisfied.
RE: Dehumidification with DX Split
if the contractor gets to pick equipment, he has to make sure it works, which in this case won't.
RE: Dehumidification with DX Split
RE: Dehumidification with DX Split
If the contractor hires you to do the design, but tries to overrule you anyway, let him and tell the costumer to call the contractor if they have humidity issues.
Write your concerns in a memo that they have to sign that they acknowledge you warned them of humidity issues.
RE: Dehumidification with DX Split
your space is small. if contractor is stubborn, put dx in, but add dedicated space dehumidifier to do the cleverest part of job.
RE: Dehumidification with DX Split
RE: Dehumidification with DX Split
RE: Dehumidification with DX Split
^^^^ agree
RE: Dehumidification with DX Split
Two: you need to downsize your AC and let it run all day to insure dehumidification.
three: relying on thermostat to dehumidify is a mistake. downsizing equipment is key. If still afraid to downsize, suggest to use two small units - one controlled with a thermostat, one controlled with a humidistat.
Four: enclosure design is important, assuming you have an air tight enclosure here, if not, you will have substantial infiltration. verify you climate and properly locate your vapor barrier
Five: Any time a contractor drives a design and issues a one directive to keep engineering fees low is a disaster.