I wonder how we'll all be able to cope - perhaps drugs (more) will be necessary?!?!

Dave

you're doing just fine

the reversed gas flow

"The smaller front PFC IS now doing the Premiere first act stage of highest heat temp condensation, rear second act or stage PFC is just idling along NOW and helping!"

If my front PFC were only a little more efficient there would be no need for the rear PFC AT ALL

I have an idea i have been sitting on for over for 3 years; prototype for a more state of the art front ONLY CONDENSER early model 911 PF (different) MICRO-CHANNEL; but I am to busy right now to test it LOL

These fools making all the BS Noise in here shot themselves in the foot

Dave you like technology go read about co2 refrigerants and A/C co2 compressors the auto industry is currently installing in cars

Selling. Not selling.

Going to explain the new idea. Not going to explain the new idea.

Rerouting. Reversing.

There is more. There is nothing more.

There is a customer and he isn't allowed to share anything.

This whole thing is an enigma shrouded in mystery.

If anyone does page the admins maybe they will delete the nearly 2 dozen pages that don't tell us any more than when this thing started.

My synopsis.

http://assets4.bigthink.com/system/i...jpg?1316183314

Eliminating the rear condenser should be possible, since Porsche did it on all 964 and after 911 derivatives. The 993 condenser, for example, is quite compact, has clever ducting and a big, high power fan. No rear condenser needed. The early 911's have space problems, but may be solvable. Great idea.
Good luck,
Dave

Post #403.

Why are you losing traction?

http://forums.pelicanparts.com/uploa...1463022419.jpg

Not sure why Mods should be called in? It's an interesting thread, and I've learned a lot about AC so far, and had many chuckles.

All these AC mods are laughable. 34F vents temps? Whut-evar. My AC goes to 11! :eek:

http://forums.pelicanparts.com/uploa...1463029043.jpg

Porsche 964 A/C IS a slightly different animal early model 911 and has its own A/C issues to make ice cold


964-993 AC Condensers OLD OBSOLETE TECHNOLOGY
964-573-011-03
993-573-011-00
993-573-011-01
993-573-011-10

I have designed PFCs for this model also but have not made them yet

I want to come out with PFCs for the 930s next

I think my rear 930 PFC design will adapt nicely for the 964 & 993

April Was Hottest Month Ever... Record Smashed AGAIN...
 

April Was Hottest Month Ever... Record Smashed AGAIN... 'Greater Than 99 Percent Chance' 2016 Will Be Warmest Year In History...

^^^

No doubt that high levels of methane produced by reversing the gasses has contributed greatly to global warming.



Are your sure that's ice?!?! :eek:

I Am SURE YOU LIE!

Jeebus, Rawknees..........

Per WIKI

Publishers point to "many longtime Almanac followers claim that our forecasts are 80% to 85% accurate" on their website.[1] Professional meteorologists refute this pointing to historical results of below 50 percent accuracy rate.

Get out and drive ten minutes and check vent temps. They will not be 27.

Butt-of-course. (RIP to our dear departed friend).

Bobasaurous, correct; on a mid-upper 90s day, the average temps will only be in the 29-30 degree range! After all, the limitations of my obsolete a/c componentry are well known, so please keep your expectations realistic!

https://server4.kproxy.com/servlet/r...1416531438.jpg

It's been a while since everyone has seen this annoying thread. Thought I'd bring it back for Memorial Day to remember those we've lost, and those who were sadly taken from us too early when removed from the forums during the "reverse the flow" war.

I think I might be on to something!


I asked my grandma to test this. ( disinterested third party). I had her take the top off our shop vac and put the hose in the different hole. Now it blows instead of sucks. And according to this found on the Internet .. "Air is a mixture of gases, 78% nitrogen and 21% oxygen with traces of water vapor, carbon dioxide, argon, and various other components. We usually model air as a uniform (no variation or fluctuation) gas with properties that are averaged from all the individual components.
Grandma is reversing the gases to blow her driveway! That doesn't suck!http://forums.pelicanparts.com/uploa...1464580621.jpg

^^^

Bob K. sez yer Grandma's a hottie!

And as a bonus, I bet she's way more pleasant to converse with than Reid/Kellogs!

Learn The Basics That Apply To all a/c sytems in 30 mins
 

Basic Refrigeration Cycle: Apply to all A/C & Refrigeration Systems

Very Easy To Understand FOR DIY; detailed system knowledge

<iframe width="640" height="360" src="https://www.youtube.com/embed/c3IieMtRMUQ" frameborder="0" allowfullscreen></iframe>

Reid Kelly 954-599 5235 ICECOLD911

Symptoms of Air in a Refrigeration & A/C System
 

The Professor: Symptoms of Air in a Refrigeration System | 2015-06-01 | ACHRNEWS

The Professor: Symptoms of Air in a Refrigeration System
Air May Cause a Reduction in Condensing Surface Area and High Head Pressures
FS-table.jpg
June 1, 2015
John Tomczyk
KEYWORDS Air in a Refrigeration System / condenser / John Tomczyk / refrigeration / The Professor
Reprints
No Comments

Symptoms of Air in a Refrigeration SystemAir doesn’t belong in a refrigeration system, and if it gets in, it will cause problems. Air can enter a refrigeration system in many ways, including through tube, gasket, or flange leaks; poor charging procedures; poor recovery or recycling procedures; or by forgetting to purge hoses when accessing systems.

If air gets into a system, it will collect in the top of the condenser and be trapped. Air is a non-condensable and cannot be condensed like refrigerant vapors. The liquid seal (subcooled liquid) at the bottom of the condenser will prevent air from leaving the condenser. Air will cause a reduction of condensing surface area and cause high condensing (head) pressures.

Air can enter the system through a leak in the low side of the refrigeration system. Refrigerant leaks will eventually lead to an undercharged system. Severely undercharged systems will run vacuums in the low side. These vacuums will suck in air from the atmosphere because the system’s low-side pressure is lower than the atmospheric pressure.
Know the Symptoms

The symptoms of air in a refrigeration system are:

• High discharge temperature;

• High condensing (head) pressure;

• High condenser subcooling;

• High condenser split;

• High compression ratios;

• Normal to slightly higher evaporator (suction) pressures;

• Normal superheats; and

• High amp (Horse power) draws.

Let’s take a closer look at each of these.

High Discharge Temperatures — These are caused by high compression ratios. High heats of compression are associated with high compression ratios. High compression ratios are associated with high condensing (head) pressure. The compressor has to compress suction vapors through a greater pressure range; thus, more heat is generated.

High Condensing (Head) Pressures — High head or condensing pressures are generated from the air taking up condensing surface volume at the top of the condenser. Because the air stays at the top of the condenser and doesn’t condense, it leaves a smaller condenser to desuperheat, condense, and subcool the refrigerant.

High Condenser Subcooling — The elevated condensing temperatures and pressures make the subcooled liquid in the bottom of the condenser hotter. Now there is more of a temperature difference between the subcooled liquid and the ambient to where heat is rejected. This will increase the rate of heat transfer from the subcooled liquid because the temperature difference is the driving potential for the heat transfer to take place.

The higher subcooling does not necessarily mean there is more liquid at the condenser’s bottom, it just means there is more cooling of the same amount of liquid to make the temperature difference greater. Remember, condenser subcooling is a temperature difference between the liquid temperature at the condenser outlet and the condensing temperature.

High Condenser Splits — Because the air is sitting at the top of the condenser, causing elevated condensing pressures and temperatures, the temperature difference between the surrounding ambient and the condensing temperature will be high. This temperature is defined as the condenser split.

High Compression Ratios — The higher condensing (head) pressures will cause the compression ratio to increase, causing low volumetric efficiencies and loss
of capacity.

Normal to Slightly Higher Evaporator (Suction) Pressures — A system’s thermostatic expansion valve (TXV) will control superheat as long as the pressure ranges of the valve are not exceeded. It takes a very high head pressure to exceed the pressure range of most TXVs. The TXV may overfeed a bit on its opening strokes because of the greater pressure difference across its orifice, giving it a slightly higher capacity. This may give the evaporator a suction pressure that’s a bit higher than normal.

If the amount of air in the condenser is extreme, the compression ratio will skyrocket and cause very low volumetric efficiencies. This will cause a low capacity, and the box (your 911 cabin) temperature may rise. This added heat in the box (your 911 cabin) may cause evaporator pressure to increase because of the added heat load.

Normal Superheats — As mentioned earlier, the TXV will try to maintain evaporator superheat as long as the valve’s pressure range is not exceeded. The opening strokes of TXV may momentarily overfeed the evaporator, but it will start to gain control shortly afterwards.

High Amp (Horse power) Draws — The high compression ratio will cause a greater pressure range for the suction vapors to be compressed. This will require more work from the compressor and increase the amp draw.

Publication date: 6/1/2015

Are you teaching us how to have PFCs and reversed gas in our home HVAC units? Because...all of those posts are for residential type systems, and do not really do us any good, do they?

Do you guys have a working system yet? I mean, mine will be running and cold by this weekend, and I started from scratch half way through this thread!

Condensers perform three vital functions, so keep them clean and damage-free
 

One of the main components of any refrigeration or air conditioning system is the condenser. As its name indicates, the condenser condenses refrigerant vapor sent to it from the compressor. However, the condenser also performs other important functions. The condenser has three main functions:

• Desuperheating;

• Condensing; and

• Subcooling.

The first passes of the condenser desuperheat the discharge line gases sent from the compressor. This prepares these high-pressure, superheated vapors coming from the discharge line for condensation or “phase change” from a vapor to a liquid. Remember, these superheated gases must lose all of their superheat before reaching the condensing temperature for a certain condensing pressure. Once the initial passes of the condenser have rejected enough superheat and the condensing temperature has been reached, the gases are referred to as saturated vapors. The refrigerant is then said to have reached the 100 percent saturated vapor point.

Condensing is system-dependent and usually takes place in the lower two-thirds of the condenser. Once the saturation or condensing temperature is reached in the condenser and the refrigerant gas has reached 100 percent saturated vapor, condensation can take place if any more heat is removed. As more heat is taken away from the 100 percent saturated vapor, it will force the vapor to become a liquid or to condense.

When condensing, the vapor will gradually phase change to liquid until 100 percent liquid is all that remains. This phase change is an example of a latent heat-rejection process, as the heat removed is latent heat, not sensible heat. This phase change will happen at one temperature, even though heat is being removed. (Note: An exception to this is a near-azeotropic blend [ASHRAE 400 Series blends] of refrigerants. With these blends, there is a temperature glide or range of temperatures when the blend is phase changing.) This one temperature is the saturation temperature corresponding to the saturation pressure in the condenser. This pressure can be measured anywhere on the high side of the refrigeration system as long as line and valve pressure drops and losses are negligible.

The last function of the condenser is to subcool the liquid refrigerant. Subcooling is recognized as any sensible heat taken away from 100 percent saturated liquid. Technically, subcooling is defined as the difference between the measured liquid temperature and the liquid saturation temperature at a given pressure. Once the saturated vapor in the condenser has phase changed to saturated liquid, the 100 percent saturated liquid point has been reached. If any more heat is removed, the liquid will go through a sensible heat rejection process and lose temperature as it loses heat. The liquid that is cooler than the saturated liquid in the condenser is subcooled liquid. Subcooling is an important process because it starts to lower the liquid temperature to the evaporator temperature. This will reduce flash loss in the evaporator so more of the vaporization of the liquid in the evaporator can be used for useful cooling of the product load.
DAMAGED, DIRTY, OR FOULED CONDENSERS

If a condenser becomes damaged, dirty, or fouled, less heat transfer can take place from the refrigerant to the surrounding ambient. Dirty condensers are one of the most frequent service problems in the commercial refrigeration and air conditioning fields today. If less heat can be rejected to the surrounding air with an air-cooled condenser, the heat will start to accumulate in the condenser. This accumulation of heat in the condenser will make the condensing temperature rise. Now that the condensing temperature is rising, there will come a point where the temperature difference between the condensing temperature and the surrounding ambient (the Delta T) is great enough to reject heat from the condenser.

Remember, a temperature difference is the driving potential for heat transfer to take place between anything. The greater the temperature difference, the greater the heat transfer. The condenser is now rejecting enough heat at the elevated Delta T to keep the system running with a dirty condenser. However, the system is now running very inefficiently because of the higher condensing temperature and pressure causing high compression ratios.

Figure 1 shows a condenser that has been damaged with its fins (extended surfaces) bent horizontally so no air can pass through. This scenario is very similar to a dirty condenser where no air is allowed to pass through. Figure 2 shows a different condenser located in an ocean town in Florida where its fins have been corroded or destroyed by the high concentration of salt in the air. The corroded fins impede heat transfer from the condenser, and the absence of fins mean less surface area for heat transfer from the condenser.

Even the subcooled liquid temperature coming out of the condenser will be at a higher temperature when the condenser is damaged, fouled, or dirty. This means the liquid temperature out of the condenser will be further from the evaporating temperature. This will cause more flash gas at the metering device and a lower net refrigeration effect.

The compressor’s discharge temperature will also run hotter because of the higher condensing temperature and pressure, which cause a higher compression ratio. The compressor will now have to put more energy in compressing the suction pressure vapors to the higher condensing or discharge pressure. This added energy is reflected in higher discharge temperatures and higher amperage draws.

Publication date: 6/6/2016

The Professor: The Importance of the Condenser | 2016-06-06 | ACHRNEWS

The information I am posting today has great value to early model 911s a/c DIY'ers owners knowledge and learning enhancement; THIS INFO explains highly technical aspects in much simpler terms so both laymen and still learning young technicians understand easier @ a lower level.

All this newly published information is for any kind of A/C or Refrigeration System, and also applies to any automotive, or 911 A/C System!!!

Good luck with your 911 DIY A/C modifications!

Improvement of R134a Performances by Addition of R290
 

Improvement of R134a Performances by Addition of R290 1992

I am Federally EPA UNIVERSALLY Licensed for ALL Types Refrigerants

I only use straight R-134A on 911s WITH MY PFC's and repeatedly get vent temps in the 30s F @ 95 ambient in all the early 911s I have been involved with using my newer technology

I don't promote flammable refrigerants due to their potential explosion danger or worse!!!

However I post this for scientific knowledge

http://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1139&context=iracc

don't play with refrigerants unless you truly know what you are doing, they can ALL kill you

It's been a year and 2 months.

Has the DIY cab owner reversed any gasses yet?

How long does it take to reverse gasses?

I think the article is older. FWIW.

This one states 2009. Of no consequence.

The Professor: Condenser Efficiency Affects the System

FWIW: Here's an article that breaks down superheat almost to a layman's level.

http://www.achrnews.com/articles/94178-superheat-and-subcooling-made-simple

Reid/Kellogs is still in the learning phase of his revolutionary a/c system development; aka - he's trying to figure out how mobile a/c works (hence his copy and pasting of tech article snibbits)!

Huh. Well, I enjoyed reading his long reposted articles, while driving to work this morning.
I enjoyed it because the air coming out of the vent, with an initial internal cabin temperature of 88 degrees, was 55 degrees in 3 minutes. High fan speed with a Werblerstrublens fan from Griffiths. As an aside...yes, car in garage all night, internal temp was 88 degrees this morning. some of you with your "oh, my car gets a vent temp of 40, but it's only 73 degrees outside" can suck it...

I figure an almost 35 degree delta after 3 minutes, with a fan speed so high as to prevent much temperature transfer to the air is good, huh? Turn the fan down the low, and the vent temp went to 45 degrees. That's a 43 degree delta. By the time I got to work, 20 minutes in light street traffic, the temp next to my head was 70 degrees.
I know that I had an evaporator core temp of 38 degrees (direct measurement) when filling it yesterday, that's at idle, low fan speed, car not moving (so, hot air curtain forming around car, preventing optimal condenser flow...).

No PFCs. No reversed gas. No increased engine temperature from a hot condenser.

http://forums.pelicanparts.com/uploa...1467058595.jpg

http://forums.pelicanparts.com/uploa...1467058609.jpg

http://forums.pelicanparts.com/uploa...1467058621.jpg

http://forums.pelicanparts.com/uploa...1467058632.jpg

daepp,

Thanks for the semi.

Refrigeration and Air Conditioning Systems ALL Share the same scientific basic consensus of operation regardless if they are commercial or residential etc; its not rocket science! What I have posted is very useful information; but it is a few steps above layman's and posted for those who want to learn and expand their knowledge a little higher

I have several 911 owners in south Florida running my 911 A/C system new technology inventions together with "REVERSING THE GASES" and they are All More Than Happy for the last couple of years!

This well known Calif. Cabaret owner is the first DIY I have SHIPPED TOO and given the installation info too and signed non-disclosure agreement to; he is doing a further technological A/C System addition enhancement with 30s F precise computer temperature evaporate control , besides my pfc's and "REVERSING THE GASES" invention.


Pazuzu as my reply to yours was later than your work, what are your results?

Well, as you may or may not know, my proprietary secret super duper system does not reverse the gas, since that wouldn't make much sense when you are not using a decklid condenser. As well ,I'm not using PFCs, since I instead am using this crazy new proprietary technology called a serpentine condenser...very rare, very special, made with real snakes.

Then, since I was able to do my own design work instead of suffering under someone's "non-disclosure agreement", I was able to get my system designed and built in a few weeks, using off the shelf parts and some basic garage skills. With hoses and fittings, I'd be at around $400 total ($270 for the condensers and fans, $130 for hose and fittings). Maybe $450.

So, since Southern Texas would make Miami weep in pain (and I know that, because I lived in Miami for 2 years...), my system needed to perform.

I have 3 electronic thermometers with remote bulbs, which consistently show 1 degree total variation between them. For the last week, I've had one bulb in the intake area and one in the output vent. Well, highest fan speed (with the super strong Windstorm/Werblersturmernederehf fan of Griffith), I get a 30 degree differential across the evaporator. Lowest speed, closer to 38 degree differential and 32-33 degree evaporator core temps.


Good enough?

^^^

That rocks, Mike - really good job you've done down thar in Souf TexAss (with pitiful, obsolete technology and ****)! And no shart about the "make weep in pain"; been a non-stop hot and extremely humid scorcher in Norf TexAss as of late (hotter-n-hell at night even) and I bet it's worsererer down your way!

I have made a set of PFC's for a DIY'er They Will Be Installed Reversing The Gases
 

THIS TREAD IS NOT DEAD

I started this tread on April 14-2015, 04:37 pm

Right after I custom made a a new design with a pair of matched set of Parallel Flow Micro-Channel A/C condensers for a WELL KNOWN PELICAN West Coast 86 Carrera Cabriolet DIY owner

I have stayed in contact with this DIY owner

IT'S now 2 years later

The 86 CAB owner has had a TON of things (to say the least) he has been doing on his 911 restoration project and now has moved his family to THE EAST COAST to Georgia and is finishing closing on a new house at this moment. He had towed his 911 from California.

He expects to now finish his restoration project by this spring. The A/C System is partly installed, he just rebuilt his A/C front PFC blower a few days ago; The new front and rear PFC's I made for him and new A/C hoses were installed 2 years ago.

He is personally rebuilding the transmission at this moment

Its frustrating to me this project is taking so long, but what can I do its ok, I am not doing the INSTALL!
Regardless I plan to help him complete his A/C project no matter how long it takes, I cant wait until he charges the A/C and we dial in the gases that will be computer digitally controlled.



On another note I have just contacted a Well Known Major USA heat exchanger manufacturer to make my 911 heat exchanger designs and we will sign nondisclosure agreements this week

<-- This Well Known and Helpful (but not Major) Pelican 911 BBS Poster finds this thread amusing. ;)

THIS WAS A GOOD PROVEN DESIGN, I NOW consider my design shown Obsolete !
 

THIS WAS A GOOD PROVEN DESIGN, I NOW consider my design shown Obsolete !
DUE TO MAJOR NEW ADVANCES IN MICRO-CHANNEL ENGINEERING

However look at THE TOTAL LOW WEIGHT, 5.5 pounds FOR BOTH HEAT EXCHANGERS! of my old design and the performance of my old designs.
using only 2 EXTREMELY LIGHT heat exchangers in the body cavity oem places compared to anyone else.

My new/next designs well be far more efficient due to recent advances in Micro-Channel Technology & manufacturing techniques. I am constantly changing this with state of the art engineering.

3 or 4 years ago when you first started chirping away, the idea of parallel flow condensers was pretty interesting, because they were rare to see in a generic form factor. You obviously contacted an Asian manufactuer and got them to take one of their standard designs and slightly bend it to match the decklid.

But, see, now...you can go on Amazon and buy one of DOZENS of generic form factory PFCs. Multiple sizes, fittings, mounting points, aluminum, black, with or without receiver dryer...

So, you're overpriced, over sold proprietary "non-disclosure" item is boring now.

SIX YEARS "chirping away" HERE about MY 911 PFC's I DESIGN ENGINEER AND CUSTOM MAKE
 

SIX YEARS "chirping away" HERE about MY PFC's I DESIGN ENGINEER AND CUSTOM MAKE AND KEEP IMPROVING FOR EARLY MODEL 911's A/C SYSTEMS


I DON'T DO CHEAP CHINA MICROCHANNEL; GO BUY IT WASTE YOUR CHEAP MONEY!



The more I have learned over the years the more there is to learn as this technology improves daily with NEW STATE OF THE ART.

its about time to increase production and enter the global market

This is why you catch heat.

I was interested yesterday in the advancements in micro-channel improvements you mentioned.

Why do you have to say things like this?

From my understanding, the OP has commissioned microchannel (aka PFC) condensers that fit the stock AC positions in the 911. That is a great idea and they will improve the efficiency typically by 1.25.

We also use custom sized PF condensers in our AC systems. Our (European) manufacturer, keeps the technology up to date. They have to or they would not be competitive in the market place. We do not claim this as our own design or technology. We just use them as they are more efficient.

OP, you have a good product there but to infer that you are on the 'bleeding edge' of condenser design is a bit of a stretch of the imagination. Not trying to start a fight, just sayin'

Make a run of them, do some testing, publish the price and folks will buy them. Simples! ;)