Crazy A/C Heater idea.

[TJ01WA]

I have an 84' 911 that I wish to repair the heater on, the blower and all the ducting has been removed so I thought the nicest option would be to backdate it. However then I'd have the hassle of having to modify the air ducts to fit around the A/C and the distributor, plus I have the auto temp control system and don't have a clue how it works or if I need to fix more there.

So...why not add a bit more A/C hose, a reversing valve, a relay and a switch next to the A/C controls to reverse the process as a domestic heat pump does!!!??!!!

As far as I can see theoretically it would work more efficiently than it cools. As the engine compartment where the condenser is is hotter than ambient. Plus the condenser would cool the incoming air into the engine compartment.

Has this idea been thought of before? Any A/C specialists care to comment?
If this could work it would mean you could have cooling and heating with less hardware (less weight, better looks) and the dry air from the heating cycle would defrost all windows much faster!

[billybek]

It would be possible in theory, but.....
It takes energy to make heat via the heat pump method. One thing that air/oil cooled motors have lots of is heat.... And it is free. Spinning that compressor is costing you money and power to the wheels....
It would probably be cheaper just to back date.....
Absorption cooling has been experimented with too for automotive use and it seems like it would be a good idea too, none of those in production either...

[TJ01WA]

A good point, but it could be an alternative to a gas or electric heating system for someone without heat exchangers on a custom exhaust. If it works...

I'm getting my aircon regassed in a couple of days so I'll talk to the guy, see if it's possible and how much it will cost.

[TJ01WA]

The Air-Con mechanic rang me from my shed on Wednesday in a panic on his mobile phone which was dropping in and out and the only words I heard before I got disconnected were "fuel" and "fire"!

I rang my wife and asked her to get to the shed and find out what was going on! She rang 15 minutes later and told me that the he accidentally "bumped" the fuel collector rail for the injectors, then started the engine, letting it warm up for a while before he smelt fuel went to the back of the car and saw fuel spurting all over it and evaporating before his eyes. Luckily it didn't catch fire.

Turns out I have a crack in my fuel rail and will have to get it fixed or replaced now before I can drive my beloved again.

Why is it sometimes it seems it's better to just read a book and do it yourself!