[P-man]

Are there materials that can absorb/trap heat, like can they become really hot and then stay that  way?

[buckminsterfullerene]

well yeah there are, molten salt is used in the Central Receiver System and stays hot over night and when there is no sunlight to heat the liquid and cause steam to turn a turbine and generate electricity,  but you would need about 800 ^oC to accomplish molten salt.  you might want to try some kind of oil, some people used it in my class to achieve a temperature of 137^oC using only an insulated box with a glass covering, and it could retain the heat.

[P-man]

Like oliove oil or something? That would be sweet. If you remember my fuel cell system, then you would know why I'm asking. Remember the thermal room? I have thought of a way to make it work: Get a material with quite a bit of heat capacity and it will suck all the heat out of the fuel cell and into the thermal room.

[billnotgatez]

Are you trying to create a thermal battery with this thermal room concept?

When the thermal room and the transfer material are the same temperature as the fuel cell, how are you going to convince the transfer media to continue to pump heat into the thermal room? Hint: you may be limited by one of those laws of thermodynamics. Again, it seems that none of the chemist here has posed thermodynamic answers to you, but maybe you need a physics discussion forum instead.

[P-man]

I am not creating a thermal battery, I am running a Stirling engine on the heat.

When the thermal room and the transfer material are the same temperature as the fuel cell, how are you going to convince the transfer media to continue to pump heat into the thermal room?

The accumulated heat will be released when the equilibrium is reached, maybe even a bit before.

[billnotgatez]

So is what you really need is a method of getting waste heat from the fuel cell to the hot end of the Stirling engine and not a thermal room?

[P-man]

I would like to accumulate the heat in the thermal room, then send it to the Stirling engine and then send it out and start the process over again.

[billnotgatez]

Storing heat in a container until you want to use it sounds like a thermal battery to me.

I should not encourage you, but your project sounds like fun whether it succeeds or not. Thus, think about chemicals that might have a latent heat of melting or boiling at the temperature you are interested in. At one point they were using salts that melted at room temperature to store passive solar heat. There were issues with how good that worked, but you never know.


By the way, I have heard from sources that various Stirling engines may be functional with low temperature differential heat situation but not very powerful.

Why do you reject the use of the heat to keep the vehicle warm in the winter? I think there is a method to use heat to create air conditioning as well.

[P-man]

Did I ever reject that idea? I think it is a good idea, especially for the cold Canadian winters .