Heat storage system (Prius-like insulated coolant reservoir)

[Obormot]

http://ecomodder.com/forum/showthrea...ake-27400.html

[cts_casemod]

So any updates on this project?

I just bumped on this thread while going with a similar idea. Just in my point of view storing energy wont really make a big difference and its a hell of a nightmare (such as engine block heaters, insulation...) If the car is left 12H there could be as little as half of the stored energy available. After a weekend, there's virtually nothing available. A remote tank reduces the available coolant flow and increases the warm up time.

I'm using a fuel powered (diesel/gas) heater to quickly bring the engine to temperature. a 5KW version will bring the block to a decent temperature (40-50C) in 15 minutes or so, using about 100-200ml of diesel fuel. At this point the limiting factor is the lambda sensor warm up, which should take no more than a minute.

Here's one:

https://www.youtube.com/watch?v=qcfPMQw3toU

The only mod required is the fitment of an electric circulation pump, to circulate the coolant with the engine off. Some burners have one already fitted, some don't.

No additional coolant and no expansion issues.

[Demolite]

The idea of storing engine heat for longer periods is expensive, difficult and space-consuming, I've tried. Storing a sensible amount of heat energy for 8 hours can be achieved, but the insulation and amount of material to store the heat is not very practical.

In Finland, timer equipped electrical outlets are common in private parking spaces; for using block heater and interior heaters. Two hours of running a average 1.5 kW electric heater in the cabin and a few hundred watt block heater results in a nice, thawed cabin but the engine is still quite cold. The poorly insulated engines lose most of that block heater energy to the air surrounding them.

I had an idea few months ago to use the "lost" energy in a different way. Say you use a 500 W heater to heat the block for 2 hours. That's 500 J/s * 2 * 60 * 60s = 3600 kJ of energy spent. If you spent that energy on heating plain water (specific heat 4,19kJ/kgK) a 10 liter water container could have its temperature go up over 85C, assuming no losses, and keeping under boiling point of course.

This is just theoretical, but maybe it brings into perspective how much energy that is. Heating the engine versus storing heat energy in an insulated container for quick energy transfer when actually needed.

The problem? The same as with the original heat storage idea: space and weight. Electric heating has it's advantages though, you're not bound by the engines maximum temperature of around 100 C. You could use other materials and liquids to store energy at higher temperatures. Heat wax to 200C, and make the container smaller. Going high temperature with flammable materials brings issues of burning the car down. Maybe a "pressure cooker"? At 20 bar, water boils at over 200 C too. An old fire extinguisher insulated and fitted with a copper coil and a heater?

This is where I'm now. Any ideas from you guys?

Installing a fuel heater was an option, and they are very common in diesel engines in the northern countries. Still it's not that "DIY", and prices for such systems are upwards of 500 euros, even used. Any research on fuel used for heating vs. saved fuel, other than fuel heater manufacturers own?

[cts_casemod]

I'm pretty sure we could design something based on a propane water heater with minor modifications. I've seen these which are quite small compared to a storage heater and put of 12KW.

6L LPG Instant Water Heater Durchlauferhitzer Boiler Wasserboiler 12kW | eBay

The other thing I'm planning is to modify a faulty diesel heater to run on LPG with a custom control card. This is to suit my electric car, since I cant stop and fire a diesel heater in a short period of time if my heat load is low, which is not an issue with a clean burning fuel such as propane/LPG.

Most of the faults with the diesel heater units are either clogged injector, faulty glow plug or faulty PCB. One could get them at a bargain price as such and replace the metering fuel pump, which is also expensive, with a cheap LPG fuel injector. This is just like a household boiler, where propane is burned in a closed chamber with a metered amount of air/fuel, which also makes the unit very compact.

Efficiency wise:

Fuel used.. Depends. The last petrol car I had was extremely inefficient at idle. If I had to idle in the morning just to heat up the engine for 10 minutes I could easily use one liter of fuel. In a week that's at least 10liters more. It was a 1.4L, so nothing major here.

The diesel is direct injection with a custom made mechanical injection pump, lithium startup battery and manually activated glow plugs. Fuel consumption increases, but its not more than 1l/100km, which could easily be blamed on the additional load running the blower fan and lights on winter or even the low fuel energy content due to winter additives. The electric heating on most diesels nowadays makes them warm up moderately fast both by providing both additional heat and engine loading, but this has a price on fuel efficiency.

[markweatherill]

Originally Posted by cts_casemod

If I had to idle in the morning just to heat up the engine for 10 minutes I could easily use one liter of fuel.

But... why would you be doing that?

[cts_casemod]

Originally Posted by markweatherill

But... why would you be doing that?

Because where I live, temperatures go to down to -10 so any moisture on air such as breathing, etc immediately condensates and or freezes on the windshield if it is not heated. It's impossible (and dangerous) to drive as such.

[cts_casemod]

Just finished installing the diesel heater on my EV. It appears to work rather nicelly even without the extra mass of the engine block. The complete system has about 1.5l of coolant on the hoses/heater/burner and an additional half liter on the expansion tank, which is just sitting there (not heated).

With an outside temperature of 5C the unit takes about 5minutes to go into part load (5 to 2kW) with the blower on Max. At lother fan speeds it just cycles on/off as needed. So overall, I'm quite pleased with the system. True hot air for the first time in 3 years

Rated fuel consumption is 300ml/hour at full speed. During my tests the unit used about 200ml for a whole hour as it cycled on/off.

[TimV]

And the biggest question is. Will you save 200ml of diesel everytime you use it to preheet the engine?

[cts_casemod]

Originally Posted by TimV

And the biggest question is. Will you save 200ml of diesel everytime you use it to preheet the engine?

Good question. Remember I just converted the electric car.
So far I get a boost of 30% on my range, assuming motorway driving. Short journey trips vary as I may be able to top up between them. Nevertheless the logic below applies.

1L Diesel = 2.4KG CO2 and 10.7KW net output. So assuming the burner is 80% efficient this will result in lower emissions (The UK grid average is 400g/KW) and equivalent in price (£1,10/L versus 12p/KW).

Note that power from the battery is at best 80% efficient too. We have battery sag losses/charging losses and conversion losses, not to mention battery wear.

Have yet to see when I convert the diesel, but it might be possible given the reduction in idling times before I can drive and the added confort (Same reason why they are installed in all high end diesel vehicles on cold climates

[oil pan 4]

http://ecomodder.com/forum/showthrea...ger-29085.html
http://ecomodder.com/forum/showthrea...9-a-32503.html This with an electric coolant pump, mmmmm.