We are installing a desiccant dehumidifier in our 8 sheet club this summer, primarily to gain control of humidity levels when we install our ice, and to dry out our arena after Spring shutdown (our pipes our imbedded in roughly 3" of sand/class 5 limestone above a waterproof membrane which overlays 3" of insulation). Since the icemelt cannot drain through our floor, we squeegee much of it to drains at the home end of our ice, but have had to rely on evaporation once it has melted to the class 5 material. This has not worked well in recent years, resulting in serious mold issues within the arena.
The initial plans called for installing the dehumidifier just outside sheet 1 (near hogline) and distributing the dried air via ductwork and a 3' perferated sock across sheets 1-6 (sheets 7-8 have lower ceiling). It has been suggested that we run the sock ABOVE our Alumazorb ceiling to get it out of sight. Since the Alumazorb ceiling has few gaps except for the 8-12" gap around the perimeter of our ceiling, I have some concerns that this may impact the effectiveness of the dehumidifier, but have no expertise on the subject.
I am even more concerned about the return air design. The return air will be drawn from a large (4'x4') vent roughly 4-5 feet above ice level. Our consultants have asserted that the air movement toward such a large opening should be insufficient to impact our ice, but I still have concerns and would appreciate your comments/suggestions.
Hi Larry. By good fortune, I have worked in such a situation. The rink was only four sheets, but the positions of the extraction duct and low-E ceiling were much as you describe, and we also installed a desiccant system.
Some basics first. Moisture migrates to the drier environment. Warm air is capable of holding more moisture, but the condensation/mold will happen in colder areas. Put the extraction above the ceiling and moisture will go to it. Put it in the wall and, as it extracts air and moisture, moisture will move towards that. If you are installing a 3' (three foot) sock, that's one hell of a dehumidifier, so you're going to have to be careful with airflow. Putting the sock above the ceiling is a good idea, we did that too, but all you're controlling is the airflow and not the change in humidity. Watch out that the warm dry air does not come down a corner and hit a spot on the ice somewhere, it has to be gentle and even.
The extraction sounds okay, as long as the vent is removing air from higher up and not sucking across the ice lower down. If the vent is louvered, turn it upside down (or put another louvered vent on top and upside down). We did that, no problems.
In my experience, from what you say, the sock ABOVE and the vent in the wall with upside down louvre will work fine, just watch the airflow down the walls!