Heating with a small engine

[TheBirkmeister]

I am trying to find out the feasibility of using a small 675cc propane engine (which runs a pump) to keep the v8 diesel engine on a delivery truck hot. The customer wants to find a way to keep the cab warm for the truck drivers in temperatures as cold as -25 degrees C. While making a delivery, which could last 30 minutes, the propane engine's coolant would transfer heat to the diesel engine's coolant. When the truck driver turns the truck back on after the delivery, he will get immediate access to hot air since the diesel engine is still warm.

The main concerns are whether the propane engine will produce enough heat and if approximate cost of installing this kind of system will be cost-efficient. Can anyone help me with the answers to these concerns?

 

[MintJulep]

So someone hired you to perform this analysis, but you're not capable of doing it, so you are hoping that someone here will do your entire job for you for free. Is that about it?

 

[TheBirkmeister]

I am an intern looking for a bit of direction/guidance from someone with experience. I don't want anyone to perform the analysis for me. I just want to know how I might find the results, since these kind of specs aren't listed on the engine's website. I do not have an engine to test with, otherwise I would. All I want to know is if the idea sounds like it might be possible. If not, I'll scrap it and try something else before I waste my time.

 

[vpl]

I'd be more worried about the effects of the propane during an accident.

True story: about 25 years ago, my parents had an old VW bus. However, it happened (and the story varies), the brakes on the van caught on fire. The van had been parked at the top of the driveway and eventually, the fire caused the brakes to give out and the van to roll down the driveway onto my parents carport -- where it ran into my dad's barbeque grill. The collision caused the propane tank to rupture -- resulting in a major fireball (people stopped on the interstate several miles away to watch). The house was a complete loss. Luckily all my family survived.

And you want to put a propane tank on the front of a truck so the driver doesn't get cold?

Patricia Lougheed

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[TheBirkmeister]

The truck is made to deliver propane, so there is already a large tank of propane on the back. The new design of the truck has been made with a propane engine to power the pump, since there is already a propane tank on the truck to draw from. However to save fuel, the diesel engine needs to be turned off during delivery, instead of being left on an idle. I am brainstorming ways to keep the cab warm with the diesel engine turned off during delivery.

 

[MintJulep]

Presumably the company that you are interning at has an internship program that works two ways. That is to say, the guidance from someone experienced that you seek is supposed to be someone at the company.

Of course it's possible that they just use interns as slave labor.

The heat rejection vs. load for your propane engine will be available from the engine's manufacturer. You'll have to call them to get it.

The amount of heat that you need to provide to the big diesel is a simple heat balance. But if you want to cheat the engine probably has block or coolant jacket heaters already installed, so someone has probably already figured this out.

 

[danberry]

I wouldn't mess with the truck's engine at all. Simply circulate the pump engine coolant in a separate radiator with a fan in the cab.

 

[amorrison]

Google using

engine coolant heater

 

[ivymike]

MintJ's remark The heat rejection vs. load for your propane engine will be available from the engine's manufacturer. is spot-on. You'll probably be able to find that info on their website.

675cc on propane is probably about 19hp to the flywheel, so figure about 19hp to the coolant and another 19hp to the exhaust. The heat rejection to the coolant is probably more than enough to keep the main engine coolant warm when it's really cold out if the truck is stationary.