Submitted: Saturday, Jan 07, 2006 at 23:21
ThreadID: 29450 Views:1931 Replies:8 FollowUps:8
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Hi all.
Just thinking if only the air con compressor could be driven some other way instead of straight off the engine. That little bit of horse power makes such a big difference in heavy going on a hot day (specially towing). A totally seperate unit driven by other means would be great, (stuffed if i know what), but really the systems have not changed much except for the gas. Im not criticising but these motors today have to much crap around the engine blocks , need more air flow at the front. Just my opinion any way.
Regards Axle
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Reply By: disco driver - Saturday, Jan 07, 2006 at 23:56

Saturday, Jan 07, 2006 at 23:56
Hi Axle
Series vehicles had one answer, and I am sure that Defenders still have them, those two movable things just below the windscreen and the slidey things (or in your case the windey things) in the doors.They were designed to increase air flow thru the cab in the days before A/c

Seriously, I have yet to find a 4wd that doesn't suffer from lack of grunt under heavy going with the A/c working overtime.

I expect I will hear from all the 'yota & 'ssan fans claiming that it doesn't happen to them but ????

One option that may work is to replace the engine driven cooling fan with a couple of large temp controlled electric ones and use the horsepower thus saved to counteract the A/c compressor load.

Any other suggestions out there???
AnswerID: 147083

Follow Up By: Billowaggi - Sunday, Jan 08, 2006 at 00:09

Sunday, Jan 08, 2006 at 00:09
And where does the power come from to drive the electric fans? Perpetual motion?
FollowupID: 400509

Follow Up By: D-Jack - Sunday, Jan 08, 2006 at 00:27

Sunday, Jan 08, 2006 at 00:27
Methane, it's free, safe and some of us can generate it at will. For those that can't a tin of Baked Beans or a night on the amber fluids usually do the trick!
FollowupID: 400510

Follow Up By: Axle - Sunday, Jan 08, 2006 at 00:36

Sunday, Jan 08, 2006 at 00:36
Those to moveable things are still there , and in moderate conditions work better than a lot a people would ever realise. Its just in extreme conditions ,dust heat can start to fight air con. Hydraulic power to drive fans another option maybe? Wait for the Ha HAs
FollowupID: 400512

Reply By: Member - Roachie (SA) - Sunday, Jan 08, 2006 at 00:49

Sunday, Jan 08, 2006 at 00:49
G'day Axle,
I was only lamenting a similar thing earlier today regarding the Air Cond system, but so much from the angle you're coming from (although you do raise a valid point). Rather, my thoughts were along the lines of how much more efficient the cooling system of my Patrol would be if it wasn't for the flamin great air-cond condenser that gets first bite of the fresh air that hits the front of the truck!. I was wondering if a whole air cond system could be electrically operated & roof-rack mounted (like the ones you see on top of motor homes etc). I guess it wouldn't be practical, but geez it'd be nice to see what effect the free-flowing air + the ommision of the air cond compressor + the ommision of the mechanical water pump (replace with an electric unit) + the ommision of the viscous fan (replace with a couple of BIG thermo fans)...would have on the vehicle. You'd have to have a massive alternator to supply power to a bank of batteries to keep all these electric motors running; so probably wouldn't be any better off!!!! Oh well, at least I'm thinking outside the square!!
AnswerID: 147091

Follow Up By: Axle - Sunday, Jan 08, 2006 at 01:37

Sunday, Jan 08, 2006 at 01:37
Roachie, where on the same wave lenght, roof mounted a/c been done, great idea. But what unit?? And how? All that chit away from the front of vechicle. CccccccLL.
FollowupID: 400514

Follow Up By: fisho64 - Sunday, Jan 08, 2006 at 03:09

Sunday, Jan 08, 2006 at 03:09
Hate to say it but for an AC unit of a certain capacity (BTU's), it takes a certain amount of energy to drive the compressor. Driving it straight of the engine is the most efficient way. If you use an electric motor, it will require power from the alternater, and be less efficient still. All electric motors have a "power factor", usually about 87% from memory, so you lose this straight away (13%)
FollowupID: 400516

Follow Up By: Flash - Sunday, Jan 08, 2006 at 14:50

Sunday, Jan 08, 2006 at 14:50
Energy required is one thing, and the most efficient way is to drive it direct from the engine...
BUT imagine if it could be driven by a variable speed pulley,similar to some CVT transmissions. It'd be like an inverter household aircon, miles ahead of the old on/off compressor system.
I guess we can only dream.
FollowupID: 400541

Follow Up By: Member - Pesty (SA) - Sunday, Jan 08, 2006 at 15:27

Sunday, Jan 08, 2006 at 15:27
Easy, just mount condenser from in front of radiator up on roof rack, plumb it up with pipes and fit large electric radiator fan and it will work like a dream.
Sing out when yuou want to cut holes in body for pipes etc, cos i got a new saw from father xmas and im looking for something to practice on hahahhaha.

Cheers pesty
FollowupID: 400551

Reply By: Mad Dog (Australia) - Sunday, Jan 08, 2006 at 09:57

Sunday, Jan 08, 2006 at 09:57
At times when you find you need every liitle bit of power simply turn the air con off, it's usually only for a very short for me and a very simple, cheap and effective solution.
AnswerID: 147108

Reply By: Willem - Sunday, Jan 08, 2006 at 14:28

Sunday, Jan 08, 2006 at 14:28
Yeah mate

A 5KVA diesel gennie and 100lt fuel tank set up in your trailer will do the trick.

I once saw a bloke up in the Kimberley with a Troopy, a large domestic freezer slung on the rear bar and a small genset on the roof rack running full time to keep the fish cold.

My aircon is responsible for 150 revs when running which in the overall scheme of things is buggerall.
AnswerID: 147165

Reply By: parthy - Sunday, Jan 08, 2006 at 16:30

Sunday, Jan 08, 2006 at 16:30
Alot of the long hual trucks now have evap air cons big water bottel just behind the cab air con on the roof .
They can have it on at night when there getting some sleep with out the motor running
AnswerID: 147202

Follow Up By: Dave(NSW) - Sunday, Jan 08, 2006 at 17:09

Sunday, Jan 08, 2006 at 17:09
They can run all night off the battery.but nowere near as cold as aircon

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FollowupID: 400562

Reply By: gen3rules - Sunday, Jan 08, 2006 at 23:27

Sunday, Jan 08, 2006 at 23:27
A little research would go a long way here. Most new vehicles now have air con compressors that only pump as much as required by the conditions and are internally regulated so when low pumping is required they can go to as little as 5% load or in hotter temps go to 100% capacity. Removing the compressor off the motor requires something else to drive it adding weight complexity and using more of your minimal power. Rooftop condensor evap units will remove the condensor from in front of the radiator but increase wind resistance. Just leave as is and switch off on the uphills and passing. Sometimes is the only way to pass in my hzj79 work vehicle due to its huge power not!!!

AnswerID: 147299

Reply By: Nudenut - Monday, Jan 09, 2006 at 08:05

Monday, Jan 09, 2006 at 08:05
as fisho says takes energy to drive the compressor......

we will just have to wait till they invent an absorption airconditioning system for can use the waste heat (free energy) from the engine. No other energy source required

They can do it...but still too costly at the moment. The piping system on an absorption system is heavy and bulky.
AnswerID: 147321

Reply By: brian - Monday, Jan 09, 2006 at 14:52

Monday, Jan 09, 2006 at 14:52
How about portable air conditioning for small areas eg a bedroom or living area in a house on fraser islandor a tent or camper van,Why cant an air cond unit from a vehicle be mounted in say a box and run by a 2 stroke motor such as the one used to power christie generators ????
Just a thought after haveing spent a VERY HOT week in a rented house at orchid beach with no fans and no air cond.
AnswerID: 147412

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