Heating system for a Nova

[Phill]

My cars exhaust doesn't allow for fitting heat exchangers, so I am left with the dilemma of how to ensure my screen doesn't mist up.

I had considered an electrical heater / blower - but the electrical system is going to struggle with anything that is high output. Having said that - I'm not worried about heating the car - merely demisting the screen so perhaps this is a viable option.

https://www.ebay.co.uk/itm/Universal....c100505.m3226

Mick had suggested winding copper tubing around the exhaust to act as a heat exchanger and routing the coolant liquid through a conventional heater/blower

https://www.ebay.co.uk/itm/Universal...wAAOSwSX9XBS3i

Another idea I had was to duct the air that passes over the oil cooler directly into the car to demist the screen - not sure if there would be a sufficient flow of air or enough heat though?

Alternatively, I could duct the air from the engine cooling shroud straight into the car bypassing any heat exchanger. The air would be at ambient temperature but I'm thinking the flow of fresh air would be enough to keep the screen clear?

Any advice?

[Spacenut]

Just blowing ambient air at the screen won't be effective, especially if it is wet outside - the ambient air will be saturated with moisture and will only make the problem worse. Ask me how I know The modifications manual describes a dedicated oil cooler heater which I thought would work well, but as I have a water cooled engine I cannot vouch for its effectiveness and the majority view seems to be that it will not work that well. I actually think Mick's air/water/air heat exchanger is probably the most viable method of getting clean, HOT air onto the screen.

Lauren

[Dirk]

Hi Phill,

I have been having similar thoughts about my car, but I'm not sure heat is what you need! when I put the demist on in my works car it puts the air con on and blows cold air. I bought a small blower from CBS
https://www.carbuildersolutions.com/...age-heater-fan
But its rubbish it just doesn't have enough power to blow air around the screen, I have picked up a second hand unit from an older vehicle I cant remember what but the fan is far more powerful but the unit is way to big for our cars. I have started to cut it down to its bear essentials but I still think it will have to live under the bonnet area.

Dirk

[steve]

The Electrical Blower route has disadvantages but I believe it's the best low-cost (easy to install, cheap, reasonably effective) option.

Mick's soluton is more involved, but on the plus side it's proven to work on a Nova.

The Oil Cooler option is interesting. You'll need to build a complete system capable of managing oil temperature in all scenarios (Winter/Summer), thermostatically controlled, with the secondary function of pushing warm air onto the screen, building that will keep you quiet for a while, although there are some off-the-shelf parts available:
https://www.merlinmotorsport.co.uk/p...brackets-ocd16

[Spacenut]

when I put the demist on in my works car it puts the air con on and blows cold air.

With every modern car equipped with air conditioning this is now the most widely accepted way of clearing the screen in wet or cold weather. The reason it works is because the air conditioning system de-humidifies the incoming ambient air, sucking all the moisture out of it. Also, because the air is cold, it is denser and can therefore absorb more moisture. The de-saturated air is then blown onto the windscreen and absorbs the moisture, clearing it very quickly.

So to clear the screen with cold air, you need air conditioning (compressor, expansion radiator, drier, high pressure hoses, gubbins...). Everything you need is available from CBS, but at a price!

What do you do if you don't have AC? Hot air - it is the next best way to desaturate the incoming ambient air.

Lauren

[Phill]

Thanks for the advice. I decided to go for a 600W heater/blower.
https://www.ebay.co.uk/itm/600W-12V-...72.m2749.l2649

It may or may not be up to the job, but is the simplest low cost method, so I thought I would try this first.

[BlueNova]

Looks like a promising solution Phill. I'll be really interested to hear how it performs.
Alistair

[Spacenut]

I'm sure it will be better than nothing, but 600W isn't a lot when you consider a typical water heater will put out at least double that and are typically able to produce 3 kW. Also, 600W at 12v = 50A of current from your electrical supply, which is like having the starter motor running all the time

However, all that being said, very few of us run Novas in all weathers so the more feedback we can get, the better. Technology improves all the time, clever digital thermostats and ceramic elements etc. probably mean that modern electric heaters put out a lot more heat than the hair dryers of old!!!

Lauren