I need help with selecting air cooling-heating equipment for a high humidity environment

[Lnewqban]

I need help with selecting air cooling-heating equipment for a high humidity environment within a new insulated outdoor chamber for a test laboratory in Florida.

A new 20' L x 10' W x 10' H chamber with 4" styrene insulation in aluminum panels forming walls and ceiling will contain those samples and a nozzle-free axial fan that can atomize ordinary water and propel a misty-fog stream up to 20 feet away.
The chamber has been installed on a concrete slab on grade with two floor drains.

Many material samples (5" diameter x 12" length) should be kept very wet and within a temperature range of 70 to 77 F degrees.
Those will be located in floor-to-ceiling racks that allow free circulation of humid air all around them.

My rough first idea has been to install an outdoor air-cooled heat pump for cooling-heating of very humid air, combined with an indoor air handler unit able to operate within that humid environment without inducing too much condensation (walking cooler type).

The internal insulation, blower motor and electrical heater elements of a regular AC air handler unit seem not to be suitable for managing saturated humid air.

Walking cooler condenser units seem unable to keep only the required temperature range of 70 to 77 F degrees.

Do you have experience with those, or simply a better idea or approach?

Thank you.

"Where the spirit does not work with the hand, there is no art." - Leonardo da Vinci

 

[MintJulep]

My first thought was that you should look to one of the companies that provide specialized equipment for natatoria.

My second thought was that maybe you could do it by controlling the water temperature.

If you need to keep the samples within a temperature range then you'll probably need to control both air and water spray temperature.

This seems like a very good environment for growing mold, Legionella, etc.

 

[Snickster]

I would look into the use of a ductless mini split variable refrigerant flow (VRF) heat pump system. The problem would be with all that moisture for the indoor unit, but vendor may be able to make recommendations. Toshiba, Carrier, Mitsubishi, LG and others have availble units. Possibly you can use an above ceiling ducted indoor unit and locate outside so only internal surfaces would be exposed to moisture. They are availble down to fractional tonnages and 1-ton and above units which might be in your range of application.

They are commonly used in electrical rooms now and other varying load industrial application since the variable speed compressor can reduce speed with load to provide a varying refrigerant flow to match load and prevent on-off cycling.

 

[LittleInch]

The suggestion by mint julep sounds good to me.

Use the temp of the water spray.

You have basically 100%RH.

Any cooling is going to generate large amounts of condensation and the internals will be wet.

Very few units are set up for that. The electronics would probably die before anything else.

Just chill or heat the water.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Alistair_Heaton]

don't reinvent the wheel.

Your local pot grower has all this sorted already.

There is hydroponic systems out there which keep the wet away from the electronics.

I think basically they have a heat/cooling air inlet then use ultrasonic foggers in a tank which the air flows over, then have an inverted U that then runs over the other side of the water tank to allow big droplets to fall out then into the environment envelope. The divider is just a plate under the water level. The sensors are on the "box" outlet duct for temp and humidity.

Personally I would have an immersion heater in the tank and it have an automatic contents dump if the refill valve hasn't triggered in 24 hours for legionaries protection.

I use an 8 pot fogger for humidifying my place with a room fan blowing over the top triggered by a humidity smart switch it will easily pump out 10 ltrs an hour into 30 rh room.

As for the gear I would use an HPA cassette for the indoor unit in another room. Then duct into the moist area.