Driving to work in the winter can be hazardous in foggy weather, as sometimes the windscreen fogs over quickly (one hill in particular is know for this, I think the trees breath heavily right there). The worst is in sub-zero temperatures when the windscreen fogs over and then freezes. Windscreen wipers don't do ice!
There are a few ways of heating in a conversion:
You can install a resistive heater in place of the heater core and heat the air directly.
You can install a small kettle to heat water, and circulate the water through the original heater core.
I, like many people, have been tempted by the idea of using an air-conditioner pump to provide heat in the cabin. In Tasmania this is generally called a heat pump. Heat pumps can be much more efficient than pure resistive heating, in theory you can get 300% efficiency. Great for a range-limited vehicle used often in cold weather.
I, like many people, purchased a Masterflux air-conditioning compressor from EV Works. Masterflux Compressor. This beastie runs off DC voltage, from 120 - 420VDC. Perfect for the Brumby, it can run from the 150V drive battery.
I did originally imagine that I could install a valve to allow cooling as well as heating, but that turned out to be too complicated.
A heat pump needs a condenser (the bit that gets hot) and an evaporator (the bit that gets cold). Ideally I'd put the condenser in the car in the flow of air where the heater core was. This proved impractical because everything is so small and neat. No room to bodge the connections to a condenser even if I could find one small enough and the right shape. So I decided I needed a heat exchanger to heat water, so I could circulate that through the original heater core. I did some reading and found that these things are reasonably common overseas, but no local supplier had ever heard of one. Luckily I found one on eBay from America! Circular and compact, this one was second-hand from a laboratory where it was used to cool something. This is the one I bought: Packless
Here is a picture of the purple Masterflux compressor and the 12V water pump to circulate the water through the heater core. For some reason it is sideways...
For the evaporator, I assumed that I'd use a small radiator like in a normal automotive air-conditioner. I'd run a couple of 12V fans on it. But a local air-conditioning technician guy took an interest in my project, and he convinced me that I could use my motor instead! After all, can you imagine a bigger fan than the air-cooling running through an EV motor? Plus there is the advantage that some of the heat the motor produces would be available to use as heating in the cabin.
So all I had to do was wind copper pipe around the motor. In the photos you can see a bit of the white heatsink compound I used to help with heat transfer. I managed to get the pipe wrapped around with the motor in place, with access from the top and bottom. Once I had enough coils I tightened them up using a couple of gripples (normally used to tighten wire on fences). I then made a clamp out of galvanised sheeting to keep them in place.
