Heating ideas

The space heater is enough to keep the vehicle at about 66-68 degrees F during the nights when it has been about 28-30 degrees outside. When the temperature is in the 40’s (F) I have to turn the heater down a bit or I get too warm working.

I hope that in the summer, the reverse is somewhat true, that I can maintain workable temperatures without too much effort.

I have a number of ideas/plans for heat. Since I will be involving a propane tank mounted on the road side of the vehicle, behind the front wheel (a large empty space between the skirt and the frame) I would like to leverage that fuel.

1) (propane) Forced air propane furnace
2) (diesel) Hydronic diesel heater with a re-purposed under seat heater core (this can keep the engine and /or the bus warm with valving)
3) (diesel, prime mover waste heat) Engine heat (while driving)
4) (propane) instant on hot water heater (not really a “heater” but a source of heat)
5) (diesel, apu power and/or waste heat) air conditioning – see below

#5 is a little out there and I’m not sure if I can get it done or not:

Basically, I would like to get a 1.6 litre VW diesel engine, and adapt it as an APU. It would have a very large alternator and an air conditioning compressor attached to the flywheel output. With some relatively simple valving, it is possible to combine it’s cooling system into the existing heater core. From the APU I can get heating, cooling, and electricity.

I have concerns about it’s size and weight with the additional accessories, as well as it’s overall fuel consumption. It might be ok, might not. They are relatively cheap and easy to work on, and certain models have hydraulic lifters so maintenance is not as much of an issue. Since the engine would be driving a DC system, (rectified ac alternator) RPM dependency isn’t really an issue.

The split AC system I’m looking at is a DC only split system reversible (can be used as a heat pump)

Between all of that laundry list, cooling and heating should not be terribly difficult. Budget will though!

One Reply to “Heating ideas”

  1. Vlad from the Skoolie forms said this, back at the time it was posted. Made a lot of sense and I didn’t pursue the crazy generator idea. (I’m glad I didn’t!)

    12000 BTU is just one ton unit. 1 ton AC compressors are just over 1KW.

    Here are some concerns:
    1. Weight. Do you really want to carry 300lb to charge your batteries? You need 2 KW to charge batteries and 1 KW to run your AC compressor.

    2. The Alternator you want to use is another monster (9-10 KW). What are you going to do with 10 KW power? It will charge your batteries in minutes, but in theory. In reality it will blow them or keep charging at slow inefficient rate.

    3. Fuel economy…. I don’t think diesel at idle will be very efficient.

    4. Any diesel will not like Idle or fast Idle for a long time. It will carbonize itself.

    Look at this little puppy:


    It only takes 270 g/kW-hr which is next to nothing. It delivers 4.3 KW @ 3600 rpm. You don’t even need this much. You can run it @ 1800 rpm and this will give you 2 KW to charge batteries. Also 1800 rpm makes it much easier to lower noise level.

    You can get bigger 10 HP version and attach alternator and ac compressor to it and still keep it @ 1800 rpm.

    Bigger is not always better. It will cost money to turn bigger 4 cylinder engine. It will never be as fuel saver as 1 cylinder.

    There is one more concern about automotive alternators. They are not very efficient. I am thinking about permanent magnet alternator something like this:

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