Electric AC Setup - ClassicRetroFit

[jamesrg]

Thoughts? Living in Texas and having an original R12 system, I am interested in this...

https://www.facebook.com/ClassicRetrofit/photos/a.147690648943364.1073741829.135954930116936/380853522293741/?type=3

The compressor module (front centre in the picture) goes in the smuggler's box on a LHD car. The condenser goes under the fender (replacing the washer bottle on an impact bumper car). The blower unit (top right) contains a modern fan and evaporator. All original (non A/C) vents now blow A/C air. You can now push A/C air out of any vent in the car, including warm A/C air for rapid defogging. The blower also adds recirculation capability and assists heated air flow for hot air without the need for footwell blowers.

[Rawknees'Turbo]

Jonny has said that he has a test unit (or will have) set for TexAss. Several of us discussed this system at length with him in another thread last summer - very cool (yep, a pun!) idea, butt I am skeptical that it will be up to the task for TexAss heat - I don't see how one, tiny condenser is going to cut it. I'm not trying to bash the system (as Jonny is aware), but just don't see it producing cold enough air to deal with upper 90s, blazing sun, and high humidity . . .

[jamesrg]

I emailed him and told him I would be a tester for it as well. Looks like there is a line. I will move to the back of it politely.

If the price is right it might be a good compromise to the existing units on the market.

I just acquired my 87 and it hasn't been retrofitted to 134 so I will need to do something before the Texas heat kicks in for sure.

[Bergo]

I posted a bit about it earlier, I guess my thread got moved? anyway, some more detail here: 12V AC from classic retrofit

[djpateman]

An average small car air conditioner provides 12000 to 18000 BTU of cooling. That is 1200 to 1800 watts of power required. Convert to amps and the alternator has to put out 86 to 130 amps just to service the air conditioner. How big is YOUR alternator?

[Nick Triesch]

What is the problem?? I fixed my 85 911 AC and it works great. The other morning it was 60 outside and my AC got down to 40 degrees! It works really well when it is cold outside! On hot days my car is not like an oven when the AC is on, more like a toaster that has been off for a while. So just fix the standard AC.

[jamesrg]

No offense, but it really doesn't get as hot and humid in San Diego as it does in Houston. Running the AC when it is 60 outside? and I am sure mine works great when it is 60 outside as well. But being born in Texas my blood is a little thinner, so at 60 degrees outside I am running the heater and not the AC .

[Rawknees'Turbo]

^^^

Nasty Nick is just doing some chain yankin'; deep down, he wishes he had my ballfreezing a/c in his car!!!

[Jonny H]

Originally Posted by djpateman

An average small car air conditioner provides 12000 to 18000 BTU of cooling. That is 1200 to 1800 watts of power required. Convert to amps and the alternator has to put out 86 to 130 amps just to service the air conditioner. How big is YOUR alternator?

^ These are the fundamental mistakes that everybody makes on first inspection.

Here's why:

1. The stated BTU rating of an engine driven compressor is quoted at its highest RPM which is typically geared to the max engine RPM. At low RPM, engine driven compressors typically produce around 3000 BTU. On a modern car, do you ever have to rev your engine in traffic to get the A/C to perform? Not really. My diesel daily is doing 1600 RPM at 70mph. E.g. The full compressor capacity is hardly ever used.

2. The COP of an electric compressor is typically around 2.0, so you only need half the power that you have stated. We have found that 40 to 50 amps provides enough power to outperform an engine driven compressor at idle. Our custom ECU regulates the compressor speed so that the compressor never takes more than the alternator can give. An adaptive algorithm computes the energy usage to get the best performance available for the alternator output. We do recommend upgrading to a 3.2 90A alternator which is ample.

3. the BTU rating of the compressor is not the full story either. The evaporator and the condensor both have BTU ratings as well. The overall performance of the system is not governed by compressor BTU alone.

[RSTarga]

In Texas, its all about the condensing capacity. A condenser can be small if it has good airflow. My 964 had less condenser area, but much better airflow than the engine mounted condenser.
I have a small front factory condenser + the engine condenser on my 911. It is vertical behind an RS spoiler and makes an incredible difference running R12.
On the highway I'm great, around town is a different story above 95 degrees.

[Bucketlist]

There is a group of believers that feel a 911 needs multiple condensers to operate efficiently. In my Retroair conversion Retroair complete system in my non a/c car
done a couple of years ago using state of the art evaporator and condenser I felt that a small system in this small car would be sufficient in West Texas 100* heat. I was correct, It keeps me cool on the hottest days. If there is any improvement to be made it would be utilizing (improving) the dash vent system to replace the under dash add on, which keep my knees blue.

[matthewb0051]

A guy on Instagram p911r just got the entire set up. He can also be followed at tejastreffen.com.

[Bergo]

Originally Posted by matthewb0051

A guy on Instagram p911r just got the entire set up. He can also be followed at tejastreffen.com.

That's Michael Meldrum, @p911r on instagram, the tejastreffen account is run by Antonio, Michael, Niels, and Rudy IIRC.

[Kevin911sc]

If it works it would be everything my car needs... I have no interest in reinstalling heat, but a little AC and the ability for the system to blow some warm air to clear a fogged window would be fantastic.

I'm sure a group buy would be of interest after a few beta units are out roaming the streets.

[Mick_D]

If the price is affordable I am buying one. And I'm in the heart of Texas.

[impactbumper]

Originally Posted by matthewb0051

A guy on Instagram p911r just got the entire set up. He can also be followed at tejastreffen.com.

Can't believe he fell for this. For UK, it is okay. For TX, very ambitious.

[Rawknees'Turbo]

Originally Posted by Hot Euro

There is a group of believers that feel a 911 needs multiple condensers to operate efficiently. In my Retroair conversion Retroair complete system in my non a/c car
done a couple of years ago using state of the art evaporator and condenser I felt that a small system in this small car would be sufficient in West Texas 100* heat. I was correct, It keeps me cool on the hottest days. If there is any improvement to be made it would be utilizing (improving) the dash vent system to replace the under dash add on, which keep my knees blue.

Steve, I thought of you (don't get excited! ) when I posted my "one, tiny condenser" comment - based on pics alone, it appears that your 1/2 bay, micro-channel, tail condenser is much larger () than the one used in the electric a/c system . . . interesting if this is the case or just looks that way in pics.

[RSTarga]

I'ld love to see one mounted in the car, what vents are they using? Or is this for previously air conditioned cars.

[Jonny H]

Originally Posted by RSTarga

I'ld love to see one mounted in the car, what vents are they using? Or is this for previously air conditioned cars.

The starting point is a non a/c car (or a car with the factory a/c completely removed). Additional a/c vents (if fitted) are removed, leaving just the factory vents. No 'bowtie' or under dash vents.

We've designed a new high volume blower that replaces the fresh air blower but now it becomes the blower for the whole HVAC system (including heat so you can bin your footwell blowers too).

The air distribution ducts have been reconfigured in conjunction with the new blower to provide switchable recirculation using the standard cabin sliders (which remain the same but are repurposed). The only addition to the cabin is a single push button with LED indication.

The result of all this is that heated, fresh or a/c cooled air can be directed to any vent in the car, something that isn't normally possible in a 911. E.g. We can put heat, fresh or a/c through the centre vent. Full bore heated a/c air to demist the windscreen? No problem.

A major gain for a/c is the ability to direct a large volume of cool air through the standard under dash vents, whilst also pushing it out the centre and side vents.

On early cars with no centre vents we also have a cunning plan....

[72_sporto]

Originally Posted by Jonny H

^ These are the fundamental mistakes that everybody makes on first inspection.

.

Being from Brisbane, I'm very interested in this system for my 72E. I like the fact that it discretely uses the existing vents- will be turn key and not require hard plumbing and brackets and pulleys.

Like many, it will depend on price as I only use the car a couple of times a week...

Is it possible to implement a "parked" mode where the car is kept a little cooler when parked in the sun using a solar panel on the parcel shelf or an extra battery? ( The unit running at reduced speed, perhaps?) Maybe incorporate a Peltier for this mode?