I’m looking for a composite or natural material that’s very light, and can be heated to a high temperature with propane gas, then gas turned off and put unit into a small contained area to act as a heater. Weight is an important factor.

23 minutes ago, Johnny W. Hulsey said:

I’m looking for a composite or natural material that’s very light, and can be heated to a high temperature with propane gas, then gas turned off and put unit into a small contained area to act as a heater. Weight is an important factor.

 

Welcome Johnny.

What you need is a high heat capacity material that won't boil or burn so a metal flask ofwater is out.

A brick or concrete block springs to mind as does a piece of cast iron.

You also say that weight is a consideration, but don't say whether you want more or less weight.

Sorry about that, I need the lightest weight I can get.

I think light weight is rather incompatible with high heat capacity. 

You might be better looking at something like those chemical hand warmers. One type uses the latent heat of crystallisation and is reusable by heating. 

https://en.m.wikipedia.org/wiki/Hand_warmer

Maybe if you tell us the application, someone will have some better ideas. 

Water has one of the highest specific heat capacities of any non-gas. Ammonia and Lithium are slightly larger.

https://en.wikipedia.org/wiki/Table_of_specific_heat_capacities

Hydrogen's is very large, but if you go that way you're going to need a bigger boat.

Why not keep heating

1 hour ago, Daenguybn said:

Why not keep heating

It requires external source of the energy.

Some deep cosmos spaceships use decay energy from radioisotopes e.g. Plutonium (energy from the Sun is too low)

https://en.m.wikipedia.org/wiki/Radioisotope_heater_unit

 

Edited April 12, 20205 yr by Sensei