Heat Absorbing Materials

P-man · 01-24-2006

Are there materials who can trap/absorb heat and become "supehot"? I need to trap heat and accumulate it to run a Stireling Engine.

HydrogenBond · 01-25-2006

One can look up the heat capactance of materials to get that answer. The CRC is a good source of info. I believe the best materials are going to be metals, with heavier metals better for holding a lot of heat at high temperature? If you wanted a fixed temperature, maybe a phase change of a material might be useful. For example, some low temperature waxes can be melted with solar heat, and give off their heat of fusion as they lose the solar heat.

P-man · 01-26-2006

Well it's for my fuel cell system - I want to trap the waste heat from the fuel cell. I have been looking at the heat capacity but I need some help on how to figure some stuff out.

To figure out the heat required to move x substance up y degrees the formula is,

Heat Required = (mass)(specific heat)(change in temperature).

Now I want to use it on, let's say, beryllium. I want to move 10 g of it up 10 degrees C.

Heat Required = (10.0)(1.824)(10.0) = 182.4 J

I think this is right. The problem is when I want to use the formula on something with the specific heat that is lower than one, like aluminum.

Heat Required = (10.0)(0.9)(10.0) = 90 J

Is that right? It seems too low to be right. But you never know. The brain plays weird tricks.

My last question. If I want to absorb the heat from the fuel cell, which heat capacity do I want, higher or lower? If the heat capacity is higher it takes longer to heat, but of it's lower, it can absorb less heat. What do I want?

Jay-qu · 01-26-2006

well I would say that depends - when you say you want to trap it do you want it to use for something else or as an insulator?

P-man · 01-27-2006

I want it to absorb the heat and keep it... then let it go and trap some more. Like it acts as a sponge for the heat. Maybe a bit like insulating.

Jay-qu · 01-27-2006

then you want something with a higher specific heat capacity

HydrogenBond · 01-29-2006

Metals will absorb and release the heat at the fastest rate. Whereas, something like a low melting temperature wax will absorb and release at a much slower rate. Between the two one should be able to get intermediate properties. Picture a honeycomb matrix of high conducting metal filled with low temperature wax. This would give one maximum flexibilty. Fast turn aronud via the metal matrix, and a reservoir for excess heat, that can even keep the temperature constant.

P-man · 01-31-2006

Thanks a lot. That's the info I needed.

DocOck · 03-19-2008

Along these lines, what type of material do you think would be best for absorbing heat to utilize as a heat source for a heat engine. In other words to make a heat type battery, that would stay sufficiently hot long enough to generate pressure through steam or some other system. You would utilize this heat "battery" to create steam to turn a generator. Instead of burning something, it would just stay hot enough to create steam for a period of time before it cooled off, to possibly be re-heated and re-utilized at a later time.