Has anyone done this?
I have 1,000 gal. tank.
Thinking of getting 1/4 pallet of paraffin wax 1,000# $600 + shipping.
Floats on water in top of tank.
Stores/releases at phase change about 37 times more heat per unit volume than to heat/cool water, and about 30 x on a mass basis.
Paraffin wax - Wikipedia, the free encyclopedia
"Paraffin wax is an excellent material for storing heat, with a specific heat capacity of 2.14–2.9 J g−1 K−1 (joule per gram kelvin) and a heat of fusion of 200–220 J g−1."
Phase-change material - Wikipedia, the free encyclopedia
Advantages
Freeze without much supercooling
Ability to melt congruently
Self nucleating properties
Compatibility with conventional material of construction
No segregation
Chemically stable
High heat of fusion
Safe and non-reactive
Recyclable
Disadvantages
Low thermal conductivity in their solid state. High heat transfer rates are required during the freezing cycle
Volumetric latent heat storage capacity is low
Flammable. This can be easily alleviated by a proper container
To obtain reliable phase change points, most manufacturers use technical grade paraffins which are essentially paraffin mixture(s) and are completely refined of oil, resulting in high costs
BBP