On Aug 29, 12:04 am, Richard J Kinch wrote:
ignator writes:
Water alone has 144 BTU/lb.latent
heat, just how much better can you get by adding salts or glycol? It
must change phase to store and retrieve this energy.

My constant sermon.

Refrigeration only happens effectively when you have intimate thermal
contact with a phase-changing medium. Brines or other fluid mediums cannot
work as well, because their temperatures rise as they absorb heat, and heat
transfer efficiency is all about delta T.

Homebrewers with jockey boxes will never accept that drained ice works
better than a water/ice bath, though.

No, assuming the working fluid when through a phase change, it will
melt at a constant temperature. The OP indicated -40 degree
refrigeration requirement for his cold plates. These store "cold" in
the form of a latent heat phase change of the working fluid internal
to the plate. It will only increase in temperature once all the
working fluid has melted. And only then as a function of the many
materials specific heats, and weights, and heat source being added.
ignator