Is electric heating of veg helpful?

[Adam]

I am using an electric VegTherm Mega heater and I recently got into a discussion with a UK national about what a rip of any electric heaters are in a WVO kit. His rational is that any heat added to the WVO by an electric heater will quickly be removed once the oil hits the IP and the combustion chamber. Only when the engine is warmed up will this stop, so really you should only be using coolant based heaters to warm the oil without robbing the engine of power by drawing current from the alternator.

Here is a more detail explaination of his arguement: http://www.smartveg.com/faqs/smartveg-u ... eaters.php

I'm not planning on disconnecting my VegTherm, but I see his point, I just don't know how much metal mass that could be cold the WVO is contacting before it combusts. What are the more mechanically knowledgeable people's opinions on this issue?

[mararmeisto]

Heating is required if you are using WVO otherwise it will be too think (may not seem it, but such is the case). Now, if you are using bio-diesel (which chemically 'thins' the waste vegetable oil), then a heater is not required. For more information on this whole topic, clarify further with the veggie burners on this forum.

What the UK people may have been talking about was the way the WVO tank used to be heated, which is generally not the way it is done nowadays. There are a number of inline heaters which will heat the WVO just before it hits the injectors.

[Adam]

I'm one of the veg burners I'm using both coolant and electrical heaters, my question is: Should the the oil be heated sole by coolant devices (VegMax, HotFox) as opposed to gaining some of the heat from an electrical device that ends up stealing some horse power. What the above link argues is that any heat transmitted to the oil via electrical devices is quickly removed when the oil enters a cool engine. Once the engine is up to temp than coolant based devices are sufficient to heat the oil. So electrical devices are ineefective with a cold/cool engine and unnecessary with a warm engine.

[mararmeisto]

I'm one of the veg burners I'm using both coolant and electrical heaters, my question is: Should the the oil be heated sole by coolant devices (VegMax, HotFox) as opposed to gaining some of the heat from an electrical device that ends up stealing some horse power. What the above link argues is that any heat transmitted to the oil via electrical devices is quickly removed when the oil enters a cool engine. Once the engine is up to temp than coolant based devices are sufficient to heat the oil. So electrical devices are ineefective with a cold/cool engine and unnecessary with a warm engine.

All of that being said, what does one use? I'm thinking one would HAVE to use both - one for BEFORE the engine is warm enough (electrical), and one for when the engine IS warm enough (coolant).

[Adam]

I think their point is that you don't switch over until the engine is warm. If you do any heat in the oil will be absorbed by the larger thermal mass of the engine.

Why doesn't smartveg use electrical fuel heaters?

Put simply, they’re are an ineffective and inefficient way of heating veg oil. A simple bit of mathematics will show you why...

Efficiency: Most electric heaters draw around 150 to 200 Watts of power. There’s no such thing as free power - that additional 200W needs to come some from somewhere: your fuel tank. You’ll burn more fuel to supply the required 200W.

Electrical Stress. Your alternator has been designed to supply the maximum you’re your car will reasonably need. This is likely to be headlights, rear window demister, heater fan & wind screen wipers all operating simultaneously on a cold winter’s day. If you then expect the alternator to supply an additional 200W (14Amps) you will invariably be exceeding its design limit. This over stressing of the alternator will be reflected into a shorter operating life. It’s worth remembering that engine components like alternators are ‘cost reduced’ components – a manufacturer will fit the lowest cost part to achieve the design functionality. They will not build in spare, more costly capacity.

Ineffective. From our extensive work with infrared imaging, we’ve concluded that electrical heaters simply cannot deliver the required heating power. Let us explain: on a cold start, your injection pump and engine block are at the same temperature. Starting the engine (a source of 55,000W minimum of power & heat) causes this large thermal mass to start warming. The injection pump is another thermal mass in loose thermal contact with the source of heat - the engine block.

Now, dumping a mere 200W into veg oil entering the injection pump does little to raise the actual temperature of the pump – any heat the fuel may have is quickly stripped away by the colder metal surfaces (higher mass) of the pump. Thermal contact with the still colder mass of the engine block further ensures that heat energy is quickly removed from the veg oil.

Only when the engine block has raised its temperature to move from being a heat sink to a heat source can vegetable oil be safely and reliably delivered to the injection pump. At this point, the extremely close tolerances inside the injection pump will be less subject to change through thermal inbalance and therefore less likely to fail due to premature changeover to veg oil.

[loki]

where are the laws of thermodynamics now? J/K but seriously sure some heat would be removed from the oil but that would also help the engine heat up that much more quickly and as nothing transfers heat that well the oil will retain some of the heat. I'm going to be using a one tank system so you have to use electric heaters as the coolant isn't warm and there is no other fuel to start on to heat the coolant up. Elsbett has been doing this for over 30 years and would likely not be using electric heaters if they didn't help. That being said once the engine is heated up it would be nice to switch over to just heat exchangers, I will look to see if the Elsbett system does this or not, I know it does have coolant heat exchangers as well.

[EricN]

FYI, I have my fuel temp sensor on my return line about 6" after the pump. If I turn the vegtherm off, the max fuel temp I get is 140f and it takes a long time to get that warm. With vegtherm on, i get up to 170f (or whatever I want to program the controller to) no problem. When the vegtherm cycles off, the temp drops back to 140 in a few minutes.
Take that for what you will.

[Adam]

That makes me feel that the vegtherm is worth while seeing as we are supposed to be getting the oil to 160F. My problem is that I don't have any good temp readings before the oil hits the IP and when it is returned so I can't really argue that the vegtherm is adding heat that is not being stripped out by a cooler combustion chamber. Eric, do you a vegsensor install that is cycling off your vegtherm?

[EricN]

I have the Vo controller so I can just plug the laptop in and program in any setting I want. It has the coolant sensor and fuel sensor, i can choose to have the vegtherm turn on or off at whatever fuel temp I want (even not turn on at all) and can program whatever coolant temp I want to see before the system turns on as well as delay preheating of the fuel system,etc. etc.