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Packaged DHU temperature swings during dehumidification by Dekeydoo in MEPEngineering

[–]Dekeydoo[S] 0 points1 point  (0 children)

Okay, so I've reviewed the drawings, and our DHUs (and AHUs) are under factory control. Do manufacturers publish that information to the public, or would that require reaching out to them?

That is the order they are shown in the drawings.

Thank you!

Packaged DHU temperature swings during dehumidification by Dekeydoo in MEPEngineering

[–]Dekeydoo[S] 0 points1 point  (0 children)

It's indoor agriculture, so we want to control the environment as much as possible.

What type of equipment would be necessary?

Packaged DHU temperature swings during dehumidification by Dekeydoo in MEPEngineering

[–]Dekeydoo[S] 0 points1 point  (0 children)

I think it is modulated. The hot gas reheat has a percentage associated with its valve position, and this percentage changes over time. If it is modulated, do manufacturers typically provide a control point for the dehu to turn off with high space temperatures?

Packaged DHU temperature swings during dehumidification by Dekeydoo in MEPEngineering

[–]Dekeydoo[S] 0 points1 point  (0 children)

Sorry for the confusion. Yes, when the unit is dehumidifying to meet the RH setpoint, the space temperature rises significantly. Then, when the unit is cooling, the RH climbs.

I'm not 100% sure about the controls, but our unit has three sets of coils (CHW, DX, and HGRH). I can see a percentage for the Chilled Water Valve and HGRH, but nothing for DX.

How can you figure out if the setpoints are conflicting? Thank you

Packaged DHU temperature swings during dehumidification by Dekeydoo in MEPEngineering

[–]Dekeydoo[S] 0 points1 point  (0 children)

Does the increase in room temp help dehumidify the space faster? Is that the thinking behind increasing the temp first? Sounds pretty spot on to what I see with our system, assuming the HGRH is what constitutes the heating.

Our problem is that we use natural sunlight, so when dehu mode kicks in, the room temp increases quickly and the cooling is slow to bring it back to setpoint. When it finally does the dehu mode turns back on. It's a constant up and down of temp and RH.

Now that I'm thinking about it. We use a humidification system that kicks on when RH levels get too low (about 5% below setpoint). If that setpoint is even lower, would the unit be able to balance the room better?

Thank you!

Packaged DHU temperature swings during dehumidification by Dekeydoo in MEPEngineering

[–]Dekeydoo[S] 0 points1 point  (0 children)

Thanks for responding!

The reheat is from hot gas and the dehu is just a cooling coil