Heat storage system (Prius-like insulated coolant reservoir)

[jonEmetro]

Great ideas everyone.
I have an idea for simple vacuum actuated valves. Ford uses coolant control valves inline with the heater core on their 90's Rangers and Explorers. They are strickly vacuum operated (no electrical) and I believe they open when vacuum is applied, which would mean that they would close when you turn your engine off and reopen upon startup.

[jonEmetro]

One more idea. Just found residential water heaters as small as 2.5 gallons online. Insulated and has a heating element.

[Josh8loop]

For the guys with the diesel engines, one could insulate the fuel tank, use a heat pipe setup to add heat to the fuel tank from the coolant system and store the heat there. A heat pipe setup with a clever working fluid displacer could be used to essentially turn off the export of thermal energy from the tank when the engine is turned off. Gasoline wouldn't work since it would vaporize much more than diesel, so this would naturally be a big issue.

[billyjones]

Originally Posted by retepsnikrep

High temp wax is available I think I bought some 80-90C stuff

Now you're cooking with gas.

[billyjones]

Originally Posted by Josh8loop

For the guys with the diesel engines, one could insulate the fuel tank, use a heat pipe setup to add heat to the fuel tank from the coolant system and store the heat there. A heat pipe setup with a clever working fluid displacer could be used to essentially turn off the export of thermal energy from the tank when the engine is turned off. Gasoline wouldn't work since it would vaporize much more than diesel, so this would naturally be a big issue.

Ah, kill 2 birds with one stone. Not only more efficient but reduced chance of fuel gelling.

[Josh8loop]

Originally Posted by billyjones

Ah, kill 2 birds with one stone. Not only more efficient but reduced chance of fuel gelling.

I won't say it's the best idea, just an idea! Extra heat in the fuel tank could potentially degrade plastic/rubber fuel tank components and of course the heat increases fuel volume. In tank fuel lift pumps may also be effected too. Thermal storage capacity will eb and flow with fuel quantity. I believe this all could be managed though, and enable thermal storage on board without any additional liuid or thermal storage volume added.

[NachtRitter]

Originally Posted by jonEmetro

One more idea. Just found residential water heaters as small as 2.5 gallons online. Insulated and has a heating element.

Brilliant idea!!

[Piwoslaw]

Originally Posted by Josh8loop

For the guys with the diesel engines, one could insulate the fuel tank, use a heat pipe setup to add heat to the fuel tank from the coolant system and store the heat there. A heat pipe setup with a clever working fluid displacer could be used to essentially turn off the export of thermal energy from the tank when the engine is turned off.

Just dumping the heat into the fuel tank half the problem. You need a way to move that heat back to the engine just before starting, but not too much as your fuel will get too cold.
Plus your heat capacity will vary with the amount of fuel onboard.
Plus diesel shouldn't get too warm, I think 55°C (130°F) is the limit. That's why turbodiesels have a radiator on the fuel line returning to the tank.

[Superturnier]

I think SAAB tried to store the heat in salt back in 1992.


I did a Quick search and found these:
Engine waste-heat storage. | Mechanical Engineering-CIME | Professional Journal archives from AllBusiness.com

http://www.ecotraffic.se/pdf/fordfile.pdf

[Josh8loop]

Originally Posted by Piwoslaw

Just dumping the heat into the fuel tank half the problem. You need a way to move that heat back to the engine just before starting, but not too much as your fuel will get too cold.
Plus your heat capacity will vary with the amount of fuel onboard.
Plus diesel shouldn't get too warm, I think 55°C (130°F) is the limit. That's why turbodiesels have a radiator on the fuel line returning to the tank.

I'll quote the last couple posts I made for clarification:


For the guys with the diesel engines, one could insulate the fuel tank, use a heat pipe setup to add heat to the fuel tank from the coolant system and store the heat there. A heat pipe setup with a clever working fluid displacer could be used to essentially turn off the export of thermal energy from the tank when the engine is turned off. Gasoline wouldn't work since it would vaporize much more than diesel, so this would naturally be a big issue.


I won't say it's the best idea, just an idea! Extra heat in the fuel tank could potentially degrade plastic/rubber fuel tank components and of course the heat increases fuel volume. In tank fuel lift pumps may also be effected too. Thermal storage capacity will eb and flow with fuel quantity. I believe this all could be managed though, and enable thermal storage on board without any additional liquid or thermal storage volume added.



Additionally, I will have to look into the maximum storage temperature of diesel and what consequences occur if it's heated to around 205 Deg F. Most diesels have a radiator on the return line to help cool the fuel before it reaches the tank to help with thermal expansion/pressurization, and to prevent thermal gain in a sytem that isn't designed for it. Fuel to fuel heat pipe based heat exchangers can be used to essentially keep heat in the tank where it belongs while allowing fuel to enter and exit at minimal temperatures. They use this type of technology in buildings for air to air heat exchangers.


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