Micro-Tube Parallel Flow Condenser (2 Viewers)

[flintknapper]

@flintknapper, do you know how many BTU's the stock condenser and evaporator are rated at?

No. Have never found any published data. But I can tell you that for a vehicle the size of an 80 series a minimum of 18K-22K BTU would be required. Recognize...that higher rpm (highway speeds) this same system (variable..since engine driven) might produce 40K BTU or more.

For a rear air unit (mean't to work in conjunction with the primary and sharing the same condenser).....around 16K would likely get the job done.

You'll find that when adding a rear unit...simply 'moving air' around makes a big difference for Humans and Pets. If you can provide them with circulating air 25-30°F lower than ambient (you might get more) you are going to be somebody's new hero.

 

[flintknapper]

I don't have anything in there now. Is this sealed from the factory?

EEEK...! You definitely want to do that with your new installation.

Mine was sealed at the top (factory)...but I did not have any on the sides at the time I replaced my condenser, though they might have been there at one time.

On my 100 series...the top and both sides are sealed with foam strips.

 

[Dissent]

EEEK...! You definitely want to do that with your new installation.

Mine was sealed at the top (factory)...but I did not have any on the sides at the time I replaced my condenser, though they might have been there at one time.

On my 100 series...the top and both sides are sealed with foam strips.

Oh yeah, I'm definitely doing that with the new one!

 

[-Spike-]

EEEK...! You definitely want to do that with your new installation.

Mine was sealed at the top (factory)...but I did not have any on the sides at the time I replaced my condenser, though they might have been there at one time.

On my 100 series...the top and both sides are sealed with foam strips.

Unless you did something, from the factory the condenser has lots of space around it for air to get to the radiator without going through the condenser, no foam that I'm aware of. The radiator is sealed from the factory to the core support with foam across the top, probably to keep from recycling engine air, but not across the sides or bottom, and nothing to seal the condenser to the radiator. My truck has foam all the way around the radiator sealing it to the core support, and all the way around the condenser, also sealing it to the core support. Theoretically all the air pulled by my fan goes through both the condenser and the radiator. From the factory, some of that air bypassed both of those heat exchangers completely, and a lot of it bypassed the condenser.

 

[Dissent]

Unless you did something, from the factory the condenser has lots of space around it for air to get to the radiator without going through the condenser, no foam that I'm aware of. The radiator is sealed from the factory to the core support with foam across the top, probably to keep from recycling engine air, but not across the sides or bottom, and nothing to seal the condenser to the radiator. My truck has foam all the way around the radiator sealing it to the core support, and all the way around the condenser, also sealing it to the core support. Theoretically all the air pulled by my fan goes through both the condenser and the radiator. From the factory, some of that air bypassed both of those heat exchangers completely, and a lot of it bypassed the condenser.

Wish I started with this!! LOL.

 

[ARB777]

I remember you posting a vintage air monster supercool condenser. Why not go with this now vs getting the nissen? Is it too much that it wont work for just a single ac for now? I just cancelled my denso condenser order and would like to go to a condenser that would support the rear ac in the future but would also work for the front ac for now.

 

[Dissent]

I remember you posting a vintage air monster supercool condenser. Why not go with this now vs getting the nissen? Is it too much that it wont work for just a single ac for now? I just cancelled my denso condenser order and would like to go to a condenser that would support the rear ac in the future but would also work for the front ac for now.

Two reasons; First I really want to see the stock sized unit in place and functional (think lifetime dream realized ) now that its no longer a unicorn and second I have to do some custom line work (more tools and money) including relocating the drier for the Monster unit.

I figure if the Nissens unit with foam surround and maybe an aux fan, if needed, makes some dramatic improvements then I may rethink the rear unit all together.

If I hadn't found the Nissens, I'd probably have postponed the whole thing until next year because the extra money and tools to integrate the Monster. This year is "get all the basic AC equipment to charge and maintain all 3x cars", next year we will see...

 

[Dissent]

Two reasons; First I really want to see the stock sized unit in place and functional (think lifetime dream realized ) now that its no longer a unicorn and second I have to do some custom line work (more tools and money) including relocating the drier for the Monster unit.

I figure if the Nissens unit with foam surround and maybe an aux fan, if needed, makes some dramatic improvements then I may rethink the rear unit all together.

If I hadn't found the Nissens, I'd probably have postponed the whole thing until next year because the extra money and tools to integrate the Monster. This year is "get all the basic AC equipment to charge and maintain all 3x cars", next year we will see...

Oh, the guy from Vintage Air said it's not too much to do now and update to the tees and 2nd evaporator later. If you aren't cash strapped, go Monster. We need someone to do that.

 

[flintknapper]

Well....actually got a reply from Denso about the 477-0554 condenser (often cited as being a 'parallel flow' by vendors selling it, NOT Denso).

Indeed...it is a 'Serpentine' flow condenser as we already suspected.

Denso currently makes three flow types of condensers. Serpentine, Multi-Flow and Subcooling-Modular. Their rate of efficiency is also in that order. Apparently...only the Serpentine is currently available for our 80 series.

From Denso:

Let me see if this helps:

Your original condenser (447700-0830 / 88460-60160) is a serpentine design.

As our Aftermarket (First Time Fit) products mirror our OE activities, 477-0554 is a serpentine design.

Studies have shown the multi flow design is more efficient.

Serpentine one path, back and forth.

Multi - flow / Parallel flow. More efficient

Sub Cool / Modular (includes drier device) more efficient.

 

[Dissent]

Well....actually got a reply from Denso about the 477-0554 condenser (often cited as being a 'parallel flow' by vendors selling it, NOT Denso).

Indeed...it is a 'Serpentine' flow condenser as we already suspected.

Denso currently makes three flow types of condensers. Serpentine, Multi-Flow and Subcooling-Modular. Their rate of efficiency is also in that order. Apparently...only the Serpentine is currently available for our 80 series.

From Denso:

Let me see if this helps:

Your original condenser (447700-0830 / 88460-60160) is a serpentine design.

As our Aftermarket (First Time Fit) products mirror our OE activities, 477-0554 is a serpentine design.

Studies have shown the multi flow design is more efficient.

Serpentine one path, back and forth.

View attachment 1763199

Multi - flow / Parallel flow. More efficient

View attachment 1763203

Sub Cool / Modular (includes drier device) more efficient.



View attachment 1763205

That's great information, thanks for chasing that one down. I see now that the wife's is the best, a Sub Cool / Modular system and the 80 is the worst, the Serpentine. I'm not sure if there's an aftermarket universal Sub-Cool model but that would be the best solution.

 

[Dindu Nuffin]

I got the Denso that I ordered last weekend just before you guys discovered that parallel flow on Rock Auto, and yes, it is indeed serpentine.

I did order the parallel flow from Rock Auto, and it will be here Friday... it'll be interesting to compare the two side by side before I send the Denso back.

Something I've noticed- and Flint can correct me if I'm wrong- is that the parallel flow will have tubular vertical end tanks, while anything else will either have the macaroni elbows like the pic I posed eariler, or will have the ends boxed in. It might make visually identifying these easier.

 

[Dindu Nuffin]

That's great information, thanks for chasing that one down. I see now that the wife's is the best, a Sub Cool / Modular system and the 80 is the worst, the Serpentine. I'm not sure if there's an aftermarket universal Sub-Cool model but that would be the best solution.

I think that Civic condenser I posed before is a sub cool. Again, Flint can correct me if I'm wrong here, but I believe that if the condenser has a drier on the side of it, it's a sub cool condenser. The reason I say that is that every parallel flow condenser I see that has the drier on one side has both fittings on the other side, while the ones without the drier have them on opposite sides. Referring to the cutaways that Flint posted up, you can see what I mean. Again, I'm not certain of this, but only suspect it based on what I've been able to extrapolate from these threads and what I've read/seen online.

 

[Dissent]

I think that Civic condenser I posed before is a sub cool. Again, Flint can correct me if I'm wrong here, but I believe that if the condenser has a drier on the side of it, it's a sub cool condenser. The reason I say that is that every parallel flow condenser I see that has the drier on one side has both fittings on the other side, while the ones without the drier have them on opposite sides. Referring to the cutaways that Flint posted up, you can see what I mean. Again, I'm not certain of this, but only suspect it based on what I've been able to extrapolate from these threads and what I've read/seen online.

Based on my research, that is correct. The pics uploaded by @flintknapper confirm. The RX300 unit may work out as well but it's about 2.3" taller. It would be a squeeze but I'd have to measure the opening on the 80:
RX (278 cu in) 26.75x16.625x.625 (left front block ports) vs.
LX (341 cu in) 27.8x14.29x.86 (left and right block ports)

 

[flintknapper]

is that the parallel flow will have tubular vertical end tanks, while anything else will either have the macaroni elbows like the pic I posed eariler, or will have the ends boxed in. It might make visually identifying these easier.

'Parallel flow' will have vertical end tanks/chambers but could be any number of shapes. It might well be that round (tubular) chambers are most common in Automotive applications...but any shape would work. The presence of parallel tubes (arranged horizontally) that terminate into vertical chambers...indicate parallel flow.

The presence of round 'macaroni elbows' is indicative of two things: Old School round tube & fin construction and Serpentine flow. End of story.

Then we have 'flat' tube (micro-chambered tube) construction that is also Serpentine flow. Because of the inherent strength of the tube construction...it can simply be formed into 180° bends that make tight turns back across the unit. So the 'elbows' are not easily seen.

 

[flintknapper]

I think that Civic condenser I posed before is a sub cool. but I believe that if the condenser has a drier on the side of it, it's a sub cool condenser. The reason I say that is that every parallel flow condenser I see that has the drier on one side has both fittings on the other side, while the ones without the drier have them on opposite sides.

This 'Modular'/Subcooling design is something that is relatively new. It certainly did not exist when I was engineering A/C systems (from then current technolgy) for the Motorhomes we were building at the time (some 15 years ago). So...I am learning right along with everyone else.

That said...based on the rendering sent to me (Denso) I don't think the presence of a R/D on the side of the condenser necessarily indicates a 'Modular' or Subcooling unit. Traditional parallel units still employ a serpentine 'path' (back and forth across the unit) so depending upon how many passes they make will determine where the inlet and outlets are. The R/D is still just that. (its function to remove moisture, contaminants and to store unneeded liquid refrigerant).

The major differences (apparent) in the modular unit (based on the rendering sent me) are:

The refrigerant path (though many tubes) is a mass migration in one direction.

Through some mechanism...the 'Modulator' (also the drier in this case) helps to separate the two phase refrigerant (partly gas, partly liquid at this point).

Then liquid refrigerant (condensed to saturation point) appears to be somewhat separated at the bottom of the condenser for supposed further subcooling.

So my WAG is that the 'modulator' is being used as a larger than normal vessel employed earlier in the system to aid in condenser subcooling (different from total subcooling) and to prevent flash gas since the refrigerant is right on the cusp of saturation at that point.

Then the very bottom of the condenser is supposed to have all (or mostly) liquid refrigerant (subcooled). We don't want any gas there (gas is where superheat is contained). The object is to create a solid liquid refrigerant source to the TXV at the evaporator. The cooler the better.

Remember, Subcooling (as applied to a liquid) is any temperature below its saturation temperature. Take water for example. The boiling point (saturation) of water (at sea level) is 212° F. anything less than this is said to be 'subcooled'. But there is a range of subcooling. If we cool water to 211 degrees then we have 1 degree of subcooling. If we further cool it to 150° F. we subcooled it 62° and so on. You probably drink a cup of subcooled coffee each morning. You are also breathing superheated oxygen right now.

As concerns Auto A/C...it is a careful balance of components meant to control Superheat (necessary to extract heat) and Subcooling (necessary to expel heat). There are things can we can do to improve the systems used in older vehicles (older technology). There are also things we can to do to screw them up (if we create too much an imbalance).

 

[Dissent]

This 'Modular'/Subcooling design is something that is relatively new. It certainly did not exist when I was engineering A/C systems (from then current technolgy) for the Motorhomes we were building at the time (some 15 years ago). So...I am learning right along with everyone else.

That said...based on the rendering sent to me (Denso) I don't think the presence of a R/D on the side of the condenser necessarily indicates a 'Modular' or Subcooling unit. Traditional parallel units still employ a serpentine 'path' (back and forth across the unit) so depending upon how many passes they make will determine where the inlet and outlets are. The R/D is still just that. (its function to remove moisture, contaminants and to store unneeded liquid refrigerant).

The major differences (apparent) in the modular unit (based on the rendering sent me) are:

The refrigerant path (though many tubes) is a mass migration in one direction.

Through some mechanism...the 'Modulator' (also the drier in this case) helps to separate the two phase refrigerant (partly gas, partly liquid at this point).

Then liquid refrigerant (condensed to saturation point) appears to be somewhat separated at the bottom of the condenser for supposed further subcooling.

So my WAG is that the 'modulator' is being used as a larger than normal vessel employed earlier in the system to aid in condenser subcooling (different from total subcooling) and to prevent flash gas since the refrigerant is right on the cusp of saturation at that point.

Then the very bottom of the condenser is supposed to have all (or mostly) liquid refrigerant (subcooled). We don't want any gas there (gas is where superheat is contained). The object is to create a solid liquid refrigerant source to the TXV at the evaporator. The cooler the better.

Remember, Subcooling (as applied to a liquid) is any temperature below its saturation temperature. Take water for example. The boiling point (saturation) of water (at sea level) is 212° F. anything less than this is said to be 'subcooled'. But there is a range of subcooling. If we cool water to 211 degrees then we have 1 degree of subcooling. If we further cool it to 150° F. we subcooled it 62° and so on. You probably drink a cup of subcooled coffee each morning. You are also breathing superheated oxygen right now.

As concerns Auto A/C...it is a careful balance of components meant to control Superheat (necessary to extract heat) and Subcooling (necessary to expel heat). There are things can we can do to improve the systems used in older vehicles (older technology). There are also things we can to do to screw them up (if we create too much an imbalance).

Great synopsis! I agree on the sub-cool condenser design. From what I've researched they incorporated the R/D into the condenser to eliminate that flash gas issue and to add one further step of sub-cooling. I can't find anyone who has an aftermarket version.

A question arose while reading this; the stock 80 has one of the lines running from the compressor to the firewall insulated along the exhaust manifold but then there's about 16" of non-insulated tubing, right above the exhaust. Which line is this and wouldn't it benefit the contents to be fully insulated??

 

[CJF]

So if one's condensor already cycles as per spec., will a more efficient condensor actually give you reduced cabin temps? Or just run the compressor less often?

 

[flintknapper]

A question arose while reading this; the stock 80 has one of the lines running from the compressor to the firewall insulated along the exhaust manifold but then there's about 16" of non-insulated tubing, right above the exhaust. Which line is this and wouldn't it benefit the contents to be fully insulated??

We have a line running from the evaporator to the compressor. That is the low side line (suction). It is carrying the superheated gaseous refrigerant from the evaporator to the compressor. It is this gas (from the evaporator) that has absorbed the heat from the cabin. The insulation serves two purposes, it helps prevent condensation on that line and it reduces additional heat absorption...which we don't want.. that side of the evaporator.

On the 80 series the portion of the line that is insulated is basically that which tracks close to the exhaust manifolds. If the heat from the manifolds were to be absorbed by the gas in the return (suction) line the compressor would only have to work harder (higher refrigerant temp=higher pressure). The gas is destined to be compressed anyway (temperature and pressure raised) but we want as free a flow INTO the compressor as possible.

 

[flintknapper]

So if one's condensor already cycles as per spec., will a more efficient condensor actually give you reduced cabin temps? Or just run the compressor less often?

In the event your compressor is already cycling (and the refrigerant charge is correct) then the reason it is cycling is because the thermistor on the evaporator (or some other temperature monitoring device) is trying to keep the evaporator from freezing up. So...no, the heat load under those circumstances do not warrant a more efficient condenser.

When heat load demands are high...you want a condenser that can rapidly make the heat transfer (from the high pressure gas in the condenser) to the ambient air. This gets rid of the heat and allows the gas to cool and condense back into a liquid for another trip through the TXV and evaporator. So...the condenser needs to be able to shed heat and provide the evaporator with a steady supply of subcooled (read liquid) refrigerant, (the cooler the better).

BUT....our systems incorporate a TXV (metering device) at the evaporator. When working correctly it literally regulates the amount of refrigerant going into the evaporator and thus the superheat. It tries to keep it constant. So if there is a bottleneck anywhere in the system...this is it. No matter how well your compressor and condenser are working... the TXV IS THE BOSS.

That is why I often say...of the two heat exchangers (condenser & evaporator) I consider the health of the Evap to be more important. They are often times dirty or partially clogged with years of debris. Also the TXV, if it is sticking...is going to give you trouble.

 

[Dissent]

Excellent info as usual @flintknapper. I've learned so much from this thread alone!