insulation for storage.

[leaddog]

I'm using a walk-in freezer panels for my storage tank so I'm not having a problem with heat loss in the walls but I'm wondering if I'm having any evaporation losses and if there is any good ways to hold down the evaporation. I thought of bubble wrap but I don't think it would hold up. My top is made of the freezer panels also with epdm liner attached and I don't see any steam but if I pick up a panel there is LOTS of steam coming off the water. It seems to me that if I could put something on the water it would hold it in better.
also this might be a good place to use everyones ideas on insulation for anyone making there own tanks.
One of those ir thermometers would work well to see how well the insulation is working also
leaddog

 

[Corey]

I would think that anything you can put in contact with the surface of the water will help stop the evaporative losses. The bubble wrap may look flimsy, but it is used quite a bit in the pool and hot tub industry where I suspect the chemicals - chlorine, ozone, bromine, etc would be as harsh or worse than your tank water. Even a piece of sheet plastic would work - provided you installed it so it couldn't sink, but would stay in contact with the water surface.

If you do go to one of the IR thermometers, you may want to calibrate it for the different emissivity of the materials - ie going from a copper pipe to a shiny stainless steel surface to foam insulation will all have different emissivity and may throw the apparent temperature off. One option would be to take a little bit of flat black spray paint and spray a little black patch on the surfaces you want to measure, then just assume the emissivity is around .95 While your measurements may not be absolutely accurate (ie the 'true' temperature) at least all the surfaces will be relative to each other.

 

[Nofossil]

I looked at pool / hot tub coverings (bubble wrap of different sorts). None was rated for the temperatures that a storage tank will reach. I threw in a few pounds of paraffin blocks - like you use for old-fashioned canning or making candles. It melts and makes a film on the surface. I also use a sheet of EPDM that floats on the surface. I have EPDM weatherstripping on the top edge of the tank, and the EPDM sheet is is held aganst the weatherstripping by a rigid lid made of multiple layers of foil faced foam board. In fifteen months of service, I have no measurable loss from the tank. I haven't opened it for inspection, though.

 

[Nofossil]

Clarification: When I say "no measurable loss" I mean water, not heat ;-)