Originally Posted by Eden
Thanks so much everyone! Sorry I took so long to come back, we got hit with summer so sudden that it pushed cubic installation back until this year again lol.
Does anyone know if there is a place that shows the thermal absorption and redistribution rates of various materials? Or reflection for the metal things?
I guess I'm just curious if there is a major difference in efficiency so that I can narrow down the materials vs just picking what I think is the most pretty.
Am I understanding right that steel would reflect back to the heater and protect the walls moreso than carry the heat longer? Or is it kindof similar on comparison?
Main goal for us now is using materials that can most effectively extend the amount of time we can go between messing with the fire on a cold night.
Thank you SO much for your help and the links!
Good job doing your research on materials! This can definitely go a long way in safety and efficiency.
There are two different concepts here: thermal mass (stores heat) and thermal insulation (reduces heat flow).
You want a lot of thermal mass around your heater. The most common material for this is brick. It takes a while to get hot, but then it will hold the heat for a long time, cooling off slowly. It will help to keep your bus warm as the fire dies down and also help to reduce temperature spikes when the fire gets really hot when you stoke it.
Thermal mass is characterized by the physical mass (e.g. how many bricks do you have) and specific heat (how much energy does it take for the material to change temperature). Here's a link to specific heats of some common materials:
The idea of putting steel or another metal around a wood stove is that there's an insulating layer of air behind the steel. Air is a pretty good thermal insulator - it provides a large resistance to heat flow. To clarify, the order of materials would go:
outer wall surface
air gap (about 1 inch typically)
This extra air gap between the metal and your walls is enormously effective at keeping your walls cool.
Here's a reference for the insulating properties of some different materials. A higher R-value means a better insulator, and R-value is often expressed per unit thickness of material.
ColoradoENERGY.org - R-Value Table
TL;DR: Surrounding your wood stove with brick or stone will help the heat last longer before re-stoking. Some sheet metal surrounding your wood stove with an air gap between the metal and the wall will help a lot to keep your walls at a low, safe temperature.
Hope that helps!