Classic Retrofit: Lightweight Electric Air Conditioning

[targa80]

Yesterday, I had to take my wife’s Lexus RX450h which is a hybrid to the dealer for some service. The AC system is electric because when the car is stopped at a light the engine shuts off but the AC keeps on cranking out cold air. Granted, the car has a large lithium battery bank that can carry the load without batting an eye. I did put a thermometer in the dash vent before I left the house and within two blocks the vent temp hit 40F and stayed there the whole time. It did not matter how fast the blower was going. Right after I installed the CR system earlier in the year I had the vent temp down to 40F but now that it is in the heat of the Florida summer I’m lucky to reach the low 50’s at the vent with a CTS set at 5C. This tells me that my CR system will need to reach that same vent temp to be effective. Unfortunately, the CR evaporator/blower is soaked in condensation after a short period of time. The condensation is robbing the system of cooling that never makes it to the vents. I am in the process of adding external R-6 foil backed insulation to the evaporator/blower unit and the associated ducts. I believe this will help eliminate the sweating (condensation) on the unit and help lower the vent temps.

This was after a drive showing the amount of condensation on the unit. The amount of moisture in the frunk is not good since it is not a part of the internal condensation drain system.

[Tonger]

Originally Posted by PorterF

The same thought was brought up before, Jonny commented that 2 condensers are all that's needed. My guess is that the heat transfer of two condensers has surpassed the capacity of the evaporator unit.



http://forums.pelicanparts.com/porsche-911-technical-forum/921754-classic-retrofit-lightweight-electric-air-conditioning-post11390822.html

Thanks, I also saw Jonny's earlier reply. The question that I quoted from germanwheels was after Jonny talked about the two condenser system. He never addressed whether it would be beneficial to add a third directly and I think it would be great to hear from him firsthand before taking the car down to begin the installation. Adding a third condenser while doing the install isn't so bad. Adding it later would be a pain...

Getting some guidance regarding insulating the ducts and blower housing like Targa80 is trying would also be useful. Similarly any real world data about deleting the blend valves entirely in challenging environments would also be invaluable.

A number of real world users aren't having to reduce the CR system in these climates because they are getting too cold, they are modifying to try to get more cooling.

I also emailed and called to leave a msg regarding these questions to Jonny but haven't heard anything back yet. Right now, I just need some guidance about which second condenser to purchase and how much extra line depending on whether I do a 2 or 3 condenser installation.

[Nditiz1]

I too will got the route of insulating every piece in front of the CR setup. Hopefully this will mitigate the condensation issue as well as help with the cooling.

As far as more than one condenser, I was a fan at first, but after getting almost identical test results with a single vs a double I'm not sure it is beneficial. Maybe my setup is wrong so YSMV.

Going back to Pat's setup, I have not made it stable enough to do road testing yet, but I did start the car and run it. With both fans going and both center and lowers open I was getting 14.5mph out of the center which was enough to feel on the face sitting fully back in my seat (5' 8")

[rmag911]

Originally Posted by Nditiz1

I too will got the route of insulating every piece in front of the CR setup. Hopefully this will mitigate the condensation issue as well as help with the cooling.

As far as more than one condenser, I was a fan at first, but after getting almost identical test results with a single vs a double I'm not sure it is beneficial. Maybe my setup is wrong so YSMV.

Going back to Pat's setup, I have not made it stable enough to do road testing yet, but I did start the car and run it. With both fans going and both center and lowers open I was getting 14.5mph out of the center which was enough to feel on the face sitting fully back in my seat (5' 8")

What are you planning on using for insulation? Something like this? Or a different type of material?

https://www.radiantguard.com/products/radiant-barrier-xtreme-metalized-insulation-x-1000-b?variant=31826332090442&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&utm_campaign=gs-2018-08-16&utm_source=google&utm_medium=smart_campaign&gclid=CjwKCAjw3_KIBhA2EiwAaAAlisDLKpBwsWjWhebI8_pr O8kN-K5AvGGAPdirOdKczX9v-rBRm212pBoCfTsQAvD_BwE

[Nditiz1]

Pat is using this and I am going to mirror

[VFRPeter]

Originally Posted by Tonger

I also emailed and called to leave a msg regarding these questions to Jonny but haven't heard anything back yet. Right now, I just need some guidance about which second condenser to purchase and how much extra line depending on whether I do a 2 or 3 condenser installation.

Jonny is somewhat busy, rushing around out of the office this week ahead of a show at the weekend, but I’m sure he’ll respond in due course.

If you don’t have an existing second condenser, Jonny’s website lists complete dual condenser options. These include the extra hose & fittings.


Sent from my iPhone using Tapatalk

[Tremelune]

Don't forget about engine heat...A lot of us remove the rear seats and insulation for weight savings, so as we try and figure out if a system can "keep up" in a particular car/climate, it's important to keep heat intrusion in mind...

This is a relatively stock 1970 911T with a 2.2L engine...It doesn't generate a great deal of heat (or power), but it certainly heats up the cabin. This was after normal around-town driving somewhere around 80°F ambient.

[Bill5900]

@Tremelune do you have the rear window tinted? On the parcel shelf it could be a combination.

[Bill5900]

Originally Posted by Nditiz1

Pat is using this and I am going to mirror

May I suggest foil tape as well? Radiant heat is your enemy.

[Hi_Fi_Guy]

Originally Posted by targa80

This was after a drive showing the amount of condensation on the unit. The amount of moisture in the frunk is not good since it is not a part of the internal condensation drain system.

Are you using the standard cardboard cover over the ventilation or something else? I remember reading a long time ago the better you can seal off the ventilation system from the warm ambient air in the trunk the mere effective the a/c will be. I believe some people even tried vapor barrier type materials to help seal off the ventilation from the trunk.

[rmag911]

Originally Posted by TeeJayHoward

I doubt it. I think the 006-A54-22 is the next step up, and it's 351 x 139.87 x 167.5, a significant increase in every dimension. Plus you're looking at a 34A draw instead of an 11A, which means new wiring - It may even exceed the specs for the factory plug.

Looks like 008-A54-02 has 543 CFM and is very close in size to the standard 360CFM blower. Its 320mm x 127.5 mm x 113.1mm. It comes in both 3 speed and 4 speed.

See page 68 of this Spam PDF
https://www.spalautomotive.it/documents/20182/35726/DOUBLE+CENTRIFUGAL+BLOWER+CATALOGUE+12V.-gxPguet9.pdf/b926d244-dd93-4d21-8419-a5992e074a03

https://www.spalusa.com/products/blowers/dual_wheel/008-a54-02-ra3vcv-12-dual-wheel-3-12v-30003143

[mo-mon]

Hi Pat-targa80. Sent you a pm.

[targa80]

Originally Posted by Hi_Fi_Guy

Are you using the standard cardboard cover over the ventilation or something else? I remember reading a long time ago the better you can seal off the ventilation system from the warm ambient air in the trunk the mere effective the a/c will be. I believe some people even tried vapor barrier type materials to help seal off the ventilation from the trunk.

I used the supplied fresh air blower gasket and added a foil backed insulator strip to close the opening and black tape on the the side facing the outside of the grill.

I could also add a thin foil faced blanket to separate the evaporator/blower from the rest of the frunk.

I decided to insulate the evaporator/blower/ducts because of the excessive condensation. In my opinion just using a thermal blanket to separate the exposed evaporator/blower/ducts from rest of frunk would not have eliminated condensation on the unit itself.

My next step is to go with a high UV window tinting. Yesterday, temps in Jensen beach was 90F with 78% humidity. A thermometer on the dash read 130F just after a 15 minute drive, the car was getting heat soaked. The system cabin temp was in the high 80’s and vent temp in low 50’s. The system needs to get the vent temps in the low 40’s to be effective. With the untinted glass there is no way the system will reach the low 40’s in the peak of the heat soaked Florida summer.

I have talked to other Floridians that adding a high UV tint to the windows and they all said it was a marked improvement on the efficiency of the AC cooling in the car. Won’t know how much this will help my issue until I get it done.

[PorterF]

Originally Posted by targa80

I used the supplied fresh air blower gasket and added a foil backed insulator strip to close the opening and black tape on the the side facing the outside of the grill.

I could also add a thin foil faced blanket to separate the evaporator/blower from the rest of the frunk.

I decided to insulate the evaporator/blower/ducts because of the excessive condensation. In my opinion just using a thermal blanket to separate the exposed evaporator/blower/ducts from rest of frunk would not have eliminated condensation on the unit itself.

My next step is to go with a high UV window tinting. Yesterday, temps in Jensen beach was 90F with 78% humidity. A thermometer on the dash read 130F just after a 15 minute drive, the car was getting heat soaked. The system cabin temp was in the high 80’s and vent temp in low 50’s. The system needs to get the vent temps in the low 40’s to be effective. With the untinted glass there is no way the system will reach the low 40’s in the peak of the heat soaked Florida summer.

I have talked to other Floridians that adding a high UV tint to the windows and they all said it was a marked improvement on the efficiency of the AC cooling in the car. Won’t know how much this will help my issue until I get it done.

I think the tint is a good idea, especially on a Targa. FWIW Targa Dan adds a layer of insulation as an option with his top refurbishment. This would also be easy to test with loose fitting insulation, foil barrier is recommended. Keep in mind foil needs air space on the back side to work most effectively.

Duc Hunter's thread talks about his experience with tinting and is a good reference. http://forums.pelicanparts.com/porsche-911-technical-forum/1031236-classic-retrofit-c-experience-guide.html

When shopping for tint you need heat rejection. The UV rejection is the easy part, many tints block 99%+ of UV regardless of how dark or light they are.

[rmag911]

Originally Posted by PorterF

I think the tint is a good idea, especially on a Targa. FWIW Targa Dan adds a layer of insulation as an option with his top refurbishment. This would also be easy to test with loose fitting insulation, foil barrier is recommended. Keep in mind foil needs air space on the back side to work most effectively.

Duc Hunter's thread talks about his experience with tinting and is a good reference. http://forums.pelicanparts.com/porsche-911-technical-forum/1031236-classic-retrofit-c-experience-guide.html

When shopping for tint you need heat rejection. The UV rejection is the easy part, many tints block 99%+ of UV regardless of how dark or light they are.

Has anyone found nearly clear tint? It still lowers radiant heat. But I want to avoid the dark tint look. The lightest I can find is 83%.

[PorterF]

Originally Posted by rmag911

Looks like 008-A54-02 has 543 CFM and is very close in size to the standard 360CFM blower. Its 320mm x 127.5 mm x 113.1mm. It comes in both 3 speed and 4 speed.

See page 68 of this Spam PDF
https://www.spalautomotive.it/documents/20182/35726/DOUBLE+CENTRIFUGAL+BLOWER+CATALOGUE+12V.-gxPguet9.pdf/b926d244-dd93-4d21-8419-a5992e074a03

https://www.spalusa.com/products/blowers/dual_wheel/008-a54-02-ra3vcv-12-dual-wheel-3-12v-30003143

That might actually work if someone is willing to try. 543 CFM compared to 360 CFM, but it's 29.7 amps compared to 11!

Below is an overlay, between the 2 units. The blue one is the 008-A54-02 and the black one is the one Jonny chose 005-A46-02.

The area of the outlet does look smaller on the 008-A54-02 which could impact on the amount of surface area exposed to airflow on the evaporator core.

[rmag911]

Originally Posted by PorterF

That might actually work if someone is willing to try. 543 CFM compared to 360 CFM, but it's 29.7 amps compared to 11!

Below is an overlay, between the 2 units. The blue one is the 008-A54-02 and the black one is the one Jonny chose 005-A46-02.

The area of the outlet does look smaller on the 008-A54-02 which could impact on the amount of surface area exposed to airflow on the evaporator core.

I am also thinking about installing something like the inline blowers below on the inlet lines to suck in more air from the cabin and push more air through the blower. May experiment with the cheaper model and upgrade to the more powerful one if the concept works.

https://www.chilloutsystems.com/products/clubseries-3inch-180cfm-blower

https://www.chilloutsystems.com/products/uber3-3inch-250cfm-blower

[targa80]

Originally Posted by rmag911

Has anyone found nearly clear tint? It still lowers radiant heat. But I want to avoid the dark tint look. The lightest I can find is 83%.

The tint shop I was referred to has the ceramic tint that is clear for the front windshield that is legal in Florida. They also have the same or tinted for the side and rear window. My cost will just be over 400 tax included. They are busy so I have to wait almost two weeks for the appointment.

[rmag911]

Originally Posted by targa80

The tint shop I was referred to has the ceramic tint that is clear for the front windshield that is legal in Florida. They also have the same or tinted for the side and rear window. My cost will just be over 400 tax included. They are busy so I have to wait almost two weeks for the appointment.

That's perfect. When you have it installed, could you ask the installer for the name/model of the tint he is using? I'd like to do the same.

[targa80]

Originally Posted by rmag911

That's perfect. When you have it installed, could you ask the installer for the name/model of the tint he is using? I'd like to do the same.

They advertised Vista window film and LLumar window film. Once it is installed I will post the info and my thoughts on the reduction of heat in the car.