Phase Change Material

MoonShadows

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#1
This is an interesting product for moderating temperature in a greenhouse.

I've been reading about Phase Change Material use in greenhouses. Phase Change Material evens out temperature swings in your greenhouse, providing passive climate control without any operational cost. You pay only the cost for the material and it will last for decades. It comes under a few brand names. The one I am looking at here is BioPCM.

phasechange_greenhouse.jpg

BioPCM is usually installed on the north wall. It can be easily attached with just a staple gun, and unlike insulation, it does not have to be taped or sealed because it is not insulation. It is a salt-hydrate, which has an energy capacity of 100 Btu / sq. ft.

Phase Change Material (PCM) passively absorbs and releases heat in the greenhouse through the energy transfer of phase changes, going from solid to liquid. During the day, as the material melts, it absorbs huge amounts of energy called latent heat. When greenhouse cools at night, the PCM ‘freezes’ and releases this heat. This basic energy transfer of phase changes is responsible for many technologies and materials, such as the refrigeration cycle, and heat pumps. PCM simply harness this reaction to passively store heat in the greenhouses.

It has 5x More Heat Storage Capacity than Water

By passively storing heat in the greenhouse, Phase Change Material acts like a battery, just like water barrels (also called thermal mass). However, due to the latent heat transfer of phase changes, PCM has about 5x the storage capacity as the same volume of water. It can be built into a new wall or added onto an existing wall, passively evening out temperature swings without sacrificing growing room.

biopcm copy.jpg