Humidity control for small library

[jtbookman]

Got a small library, frame construction on a slab, 2 rooms of 300 sq. ft. They are currently using a 22 year old Liebert system model MME024. This is 2-ton r-22 system that has 1-stage electric heat and a steam humidifier built in.

Considering quoting a ductless Fujitsu heat pump with 2 indoor evaporators 12,000 btu's each with outdoor heat pump of 24,000 btu's, but have concerns about adding humidification and keeping library at a 35-50% RH all year round. Did I mention we are in Michigan? I know the Fujitsu will provide the heat and ac, but mostly concerned about the RH and controlling it. I have thought about adding a Honeywell steam humidifier to the air handler. Any thoughts?

[teddy bear]

Got a small library, frame construction on a slab, 2 rooms of 300 sq. ft. They are currently using a 22 year old Liebert system model MME024. This is 2-ton r-22 system that has 1-stage electric heat and a steam humidifier built in.

Considering quoting a ductless Fujitsu heat pump with 2 indoor evaporators 12,000 btu's each with outdoor heat pump of 24,000 btu's, but have concerns about adding humidification and keeping library at a 35-50% RH all year round. Did I mention we are in Michigan? I know the Fujitsu will provide the heat and ac, but mostly concerned about the RH and controlling it. I have thought about adding a Honeywell steam humidifier to the air handler. Any thoughts?

Include a small Ultra-Aire 70H dehumidifier for maintain <50%rh during the spring/summer/fall.
Regards TB

[jtbookman]

Thanks TB-appreciate your input-Jeff

[kdean1]

I like the Honeywell products. We've installed several TruSTEAM humidifiers, including one in our house. They perform very well but need regular cleaning because of the hard water in southeast Ohio. I will be installing a reverse osmosis system on water line to the humidifier (also from Honeywell) to prevent the scale build up.

I'm not clear from your description, is there an air handler in addition to the Leibert unit where you can mount the humidifier?

[pmeunier]

I like the Honeywell products. We've installed several TruSTEAM humidifiers, including one in our house. They perform very well but need regular cleaning because of the hard water in southeast Ohio. I will be installing a reverse osmosis system on water line to the humidifier (also from Honeywell) to prevent the scale build up.

I'm not clear from your description, is there an air handler in addition to the Leibert unit where you can mount the humidifier?

Why reverse osmosis and not a water softener?

[kdean1]

Why reverse osmosis and not a water softener?

I got the RO because that's what Honeywell makes. I'll have to ask the Honeywell rep why that is what they offer.

For some people a water softener is a bad choice because of the salt which replaces the minerals.

[jtbookman]

I like the Honeywell products. We've installed several TruSTEAM humidifiers, including one in our house. They perform very well but need regular cleaning because of the hard water in southeast Ohio. I will be installing a reverse osmosis system on water line to the humidifier (also from Honeywell) to prevent the scale build up.

I'm not clear from your description, is there an air handler in addition to the Leibert unit where you can mount the humidifier?

There is an air handler with the Liebert. I am considering though mounting the steam humidifier onto a wall and let it "mist" into the room, it's a small space. My supplier says that it will provide plenty of humidity.

[TalkingHead]

You might consider a steam humidifier with remote blower for direct room humidification. It would operate without the need for ductwork. Look for a Model DS15P by General Aire. You can also find a Honeywell T775 modulating humidistat that will output a 0-10 volt signal to control the steam production so that it ramps up and down instead of on/off operation to provide better humidity control independent of the temperature. If you research preservation you will find that keeping the humidity constant is more important than controlling the temperature.

[jtbookman]

Talking Head, I didn't consider the modulating humidistat (wasn't aware there was one) That is an EXCELLENT Recommendation. I was concerned about over-humidifying the area, and adding a de-humidifier, but this is better yet. I am going to get on my wholesaler as to why he didn't recommend such an option. THANKS

[kaleun]

Personally I think you don't need to worry about humidity in a library unless you have collector's item books (like that 1500 year old bible) that you never check out. It is a waste of money and energy and if your are unlucky you create mold.

Books get checked out all the time and people have them laying in their homes, cars or wherever without any consideration for humidity.

If you are concerned about human comfort, having just an energy recovery will retain enough moisture. Keeping 30-50% RH in cold Michigan is just asking for trouble in you walls/windows.

all our maintenance people do with humidifiers is disable them eventually because maintenance is such a hassle and occupants don't notice anyway.

Humidifiers also are a control nightmare since humidity senors are not that accurate and you can run into the problem to disturb economizer mode (remember, the purpose is to get humidity out, not in!). Put the moldmachine ah humidifier on the curb where it belongs. Sorry if I sound so negative on humidifiers, but unless you have the draftiest building in dry climate you don't need one. We have 8 libraries (and one of 100,000 sf currently bid out) and no one from the design team or library folks claims to need a humidifier.

Unless you find a way to sell mold for money, don't humidify buildings

Museums with special artifacts, specialized labs or hospitals are the only places where I can see the need, not a public library.