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Being a Peltier heat pump using a semi conductor, it seems to me that this thing has no defrost – hence the icing at low temperatures.
By their nature, Peltiers are limited in their thermal capacity. Larger de-hums that use a compression cycle are equipped with an automatic defrost system – a thermostat, timer and electric heater - to periodically remove frost build up on the evaporator surface.
When de-hums get even bigger, they use a desiccant that is continually regenerated by heat. These are very energy-greedy for what they do and can remove large amounts of moisture at a time; more suited to industrial drying.
Even so and looking at its modest moisture removal, (600 ml per day) I can see a use as a conditioner for small stacks of timber that can be arranged in stick and then to have a plastic tent erected around it. You may then simulate a centrally heated environment. This removes the need to take it indoors for makers of small runs of pieces.
But what do you want it for? Workshop conditioning? Timber drying? To moisture condition a decent sized workshop, I guess that you’d need several of these.
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