Heat storage system (Prius-like insulated coolant reservoir)

[Josh8loop]

I purchased an vacuum insulated dewar on ebay recently, and will be pursuing thermal storage for my TDI as seen here:

If you could store 1.5 gallons of hot engine coolant would it help MPG's.... - TDIClub Forums


I'm still figuring out how exactly to implement these devices and how to construct the flow loop.


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[Josh8loop]

Looks like I recived the Dewar this afternoon-Can't wait to get home to try it out!! I will need to get some dimensions so I can figure liquid storage volume, and also so I can create the heat exchanger for it.

[meelis11]

Originally Posted by Josh8loop

Looks like I recived the Dewar this afternoon-Can't wait to get home to try it out!! I will need to get some dimensions so I can figure liquid storage volume, and also so I can create the heat exchanger for it.

Please make pictures to show your work Can it fit under the hood?

[Josh8loop]

Originally Posted by meelis11

Please make pictures to show your work Can it fit under the hood?

This one won't fit under the hood unfortunately. Most likely needs to be installed under the drivers side front fenderwell area. I will try to get a video of the Dewar, and some simple heat pipes that I have constructed as well.



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[Josh8loop]

Well, it holds less than I was hoping. Liquid capacity a little over a gallon. That's too bad. Price was right though!


Update on an experiment I am conducting. Since I was curious to see just how long this 1 gallon capacity Dewar would hold a liquid hot, I made a quick lash up of an experiment last night. At 10:45 last evening I placed one gallon of boiling water into the dewar. I created a foam 6" diameter top to help keep heat loss through the top to a minimum. I poked a cheap digital temp probe in the container through the insulated styrofoam top and let the temperature stabilize. Basically it stabilized at 202 Deg F, and at 6:45 am this morning it was at 172 Deg F, at 9:45 am this morning it was at 163 Deg F, and at 10:45 it was at 161 Deg F. My experiment was only with water(not paraffin as planned), and certainly not under the optimal conditions, but at least I have some kind of idea what the heat storage capacity will be like.

Next on the agenda is to get some dimensions and make the heat exchange portion a reality.

[astra74]

Sorry to dig up an old thread, but but i was thinking about this and i remembered this thread.

Any updates on this issue? Did you actually get to the implementing and testing of the system?

[meelis11]

Originally Posted by astra74

Sorry to dig up an old thread, but but i was thinking about this and i remembered this thread.

Any updates on this issue? Did you actually get to the implementing and testing of the system?

Yes, I want to know that too! I want to know how it works in real life - how long it holds temperature and how much that 1 gallon of wax can increase engine temperature.
Probably what is needed is electric circulalion pump - so you can release heat before starting the engine.
And then at least one solenoid valve and controller something like this http://www.ebay.com/itm/Automatic-Di...item25716f4675

[Galane]

From wikipedia. Paraffin wax is an excellent material to store heat, having a specific heat capacity of 2.14–2.9 J g−1 K−1 (joule per gram kelvin) and a heat of fusion of 200–220 J g−1.

Paraffin - Wikipedia, the free encyclopedia

[elhigh]

Originally Posted by Ryland

How about filling your heat storage tank with something like paraffin wax instead of water then having a closed coil of tubing in the wax, as I understand it paraffin wax holds a lot more heat in the phase change of going from a solid to a liquid and the temps that you are looking at seem about right for wax heat storage.

That crossed my mind when I saw the subject line. Wax is generally lighter than water, but I don't think the weight savings would be significant. The big benefit here though would be getting that heat of fusion for some serious capacity. I don't know how that would compare with the mass of water you're carrying.

I am rapidly getting beyond my knowledge here, and if I try to dig too deeply into the subject, I will embarrass myself and annoy you with my ignorance.

I think VW did a concept of this some years back, but I think they used something called Glauber's salt.

The energy stored is comparable but the wax's performance envelope is at a higher temperature. Glauber's salt does its thing about 32 deg. C. If you wanted to give up more space and tote around more weight, you could have a two-stage system that quickly brought your engine up to near operating temperature.

[Teemo]

Hello. This seems wery interesting idea. As a eco solution one could use beeswax.
Wax expands as it melts, opposite to the water, so might need bigger expansion tank.
So this system is taking shape. My abstract of the system, as I understand at the moment:

1.Use old 10L already insulated water boiler, may have electric heater also.

2.Add wax to the boiler. Can't just add wax to the coolant, so pack it in some rubber bag, or heat resistant plastic bag, or pipes, and place it inside boiler. Some water siphones have suitable rubber bags.

3.Connect it to the vehicles cooling system with hoses, and some kind of valve or thermostat.