Seneca A/C Airflow mods

[Rustynuts]

After seeing a YouTube video of a new product from RVAirflow to improve the AC/Heat Pump efficiency, I opened mine up on our Seneca and was shocked (well not really) at the the quality of the factory installation. The factory cutouts into the duct work looked like somebody just poked their hand through the foam and then taped it off sloppily. So I removed all the old crappy tape, cut foam inserts to fill the voids, cut out the foam into the ductwork clean and square and taped everything up. Then I 3D printed some pieces to tape in to create smooth clean transitions for air flow similar to what the $170 foam insert from RVAirflow does. Got everything taped in place and sealed off the air outlet side. I also eliminated the inner air dump panel as all the air is now directed into the ductwork and this leave more area for air intake. I took readings from every duct with an anemometer before I started and after. Every duct saw an increase of at least 1.5 mph airflow with the ends of the duct runs at the front and back of the coach seeing the most, the 2 front ducts saw an increase from 5.1 mph to 11.6 mph airflow! Quite a noticeable difference and well worth the time. This was just with one AC unit running, a bonus is the AC unit is quieter as the fan area is boxes off and insulated now. Most of this work is not Seneca related and could be done on any RV with ceiling duct work, I highly suggest you at least check the tape job and clean up the cutout to the duct work. The pieces I 3D printed for air flow could easily be formed out of some sheet metal or carved out of foam. The key is to reduce the turbulence and make the air flow more efficient. I opened up the rear AC and it looked the same as the front so I am also doing that one. This should make a huge difference in the summer heat.

[don_kleinschnitz]

Originally Posted by Rustynuts

After seeing a YouTube video of a new product from RVAirflow to improve the AC/Heat Pump efficiency, I opened mine up on our Seneca and was shocked (well not really) at the the quality of the factory installation. The factory cutouts into the duct work looked like somebody just poked their hand through the foam and then taped it off sloppily. So I removed all the old crappy tape, cut foam inserts to fill the voids, cut out the foam into the ductwork clean and square and taped everything up. Then I 3D printed some pieces to tape in to create smooth clean transitions for air flow similar to what the $170 foam insert from RVAirflow does. Got everything taped in place and sealed off the air outlet side. I also eliminated the inner air dump panel as all the air is now directed into the ductwork and this leave more area for air intake. I took readings from every duct with an anemometer before I started and after. Every duct saw an increase of at least 1.5 mph airflow with the ends of the duct runs at the front and back of the coach seeing the most, the 2 front ducts saw an increase from 5.1 mph to 11.6 mph airflow! Quite a noticeable difference and well worth the time. This was just with one AC unit running, a bonus is the AC unit is quieter as the fan area is boxes off and insulated now. Most of this work is not Seneca related and could be done on any RV with ceiling duct work, I highly suggest you at least check the tape job and clean up the cutout to the duct work. The pieces I 3D printed for air flow could easily be formed out of some sheet metal or carved out of foam. The key is to reduce the turbulence and make the air flow more efficient. I opened up the rear AC and it looked the same as the front so I am also doing that one. This should make a huge difference in the summer heat.

Rusty that looks great and thanks for sharing. It's been on my list and now I don't have to do the research.
Impressive improvements.

[2naEagle]

That looks great. You are a foil tape artist. Thank for sharing.

[rgolding]

Really impressed with any idea that could help reduce the noise. This has been a big factor for us on, especially, the 15 BTU forward AC unit. Thank you for sharing. I'll look into this.

[PaulB12]

Seventh pic down--what is the triangle shape?

PaulB12

[Rustynuts]

Originally Posted by PaulB12

Seventh pic down--what is the triangle shape?

PaulB12

That is one of the 3D printed parts. It is a air deflector that works with the upper ones to smoothly direct the air flow towards the air ducts on each side. Here is a pic of the CAD drawing showing the 3 pieces together and a pic of the actual part. I made the actual part a little smaller than the drawing was so I could make it in one piece on my printer.

[PaulB12]

Ok, that's what I thought. I don't have a 3-D printer so will improvise.
I like your design and have already duct taped things up sealing a lot of leaks.

PaulB12

[Rustynuts]

Originally Posted by PaulB12

Ok, that's what I thought. I don't have a 3-D printer so will improvise.
I like your design and have already duct taped things up sealing a lot of leaks.

PaulB12

After I saw the video on YouTube I started searching the internet and people have been doing things for a while to improve the airflow. Many people have just taped 2 pieces of foam together to make a triangle, having a 3D printer just made it easier and optimal. Here are a couple pics that I saved in my searching

[Rustynuts]

I finally finished cleaning up the rear AC and got the final air flow numbers and its pretty amazing and should make a huge difference in cooling and heating. The first column is the way it comes from the factory and the readings are in MPH recorded at each vent with both front and rear AC's on "Hi Fan". The second column is after cleaning up the duct cutouts, sealing off holes into ceiling cavity and adding the 3D printed parts to direct the flow. again both AC's on "Hi Fan". I had quite a mess to clean up though as the higher air flow blew all kinds of sawdust, duct trimmings as white foam all over!

[Jay2504]

That looks great, Rustynuts! I am going to do something similar on my 24RBS that has a Brisk air II. I like the part where the unit is more quiet. Jay.

[lslblues]

Would you mind sharing the 3-D printer files?

[Rustynuts]

Originally Posted by lslblues

Would you mind sharing the 3-D printer files?

I can, send me an email in a private message.....but out of my 2 ac units they were both installed a little crooked by about 3/32” to 3/16” and I didn’t really want to loosen and break the seal to move the units. I ended up trying to make them with a loose fit around the bolts which can be taped to seal around the bolts. I ended up putting a bevel on one edge to clear the welds on the aluminum frame. The center divider section is pretty much universal.

[don_kleinschnitz]

Rusty Nuts,
Thanks for sharing your work!
A related question.
What airflow meter do you use to make these measurements. I have getting one on my list and now I have a good reason to get one .

[lslblues]

Sent. Thanks.

Originally Posted by Rustynuts

I can, send me an email in a private message.....but out of my 2 ac units they were both installed a little crooked by about 3/32” to 3/16” and I didn’t really want to loosen and break the seal to move the units. I ended up trying to make them with a loose fit around the bolts which can be taped to seal around the bolts. I ended up putting a bevel on one edge to clear the welds on the aluminum frame. The center divider section is pretty much universal.

[Rustynuts]

Originally Posted by don_kleinschnitz

Rusty Nuts,
Thanks for sharing your work!
A related question.
What airflow meter do you use to make these measurements. I have getting one on my list and now I have a good reason to get one .

This is the one I have.


https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[rodpod]

Brilliant idea and innovative design. i would love to get the code for the 3d prints. I have a 2018 Greyhawk with the15000 BTU Coleman A/C. My printer has a 200mm bed. If your print will fit and you are willing to share. Please let me know.

[lslblues]

I was able to print on my Creator Pro, although I did have to split the triangle piece into 2 halves.

Brian - it'd be great to just post on Thingiverse.

I was also wondering if a diverter wouldn't help in the racetrack ducts where it T's off the duct cutouts. I saw lots of things about how much more efficient rounded corners than square corners due to turbulence. Not sure if a diverter along the back would help.

[Rustynuts]

Originally Posted by lslblues

I was able to print on my Creator Pro, although I did have to split the triangle piece into 2 halves.

Brian - it'd be great to just post on Thingiverse.

I was also wondering if a diverter wouldn't help in the racetrack ducts where it T's off the duct cutouts. I saw lots of things about how much more efficient rounded corners than square corners due to turbulence. Not sure if a diverter along the back would help.

How did the upper pieces fit on your unit? How did you print the center piece, I printed it standing up on one end.



I also though about that. In Fusion 360 I can easily scale the triangle diverter down and to stick in the back of the duct where the air blows in but with the air flow readings Im getting, Im not sure it is needed. I may give it a try. I have got some rubber door stops to try sticking up in the 4 vents that are showing low flow. I checked for any obstructions and the duct is clear, I just think the air is moving so fast now and these 4 vents are so close to the blower. These door stops supposedly help direct some of the air out the vent. Worth a try, its all an experiment.

[Rustynuts]

Originally Posted by rodpod

Brilliant idea and innovative design. i would love to get the code for the 3d prints. I have a 2018 Greyhawk with the15000 BTU Coleman A/C. My printer has a 200mm bed. If your print will fit and you are willing to share. Please let me know.

The files are available on Thingiverse now. I will be adding my other RV related files shortly.


https://www.thingiverse.com/thing:4662142

[rodpod]

Thanks so much. I'll start this right away. in you pic on the 9th one down or next to last, it looks like you taped over an opening or something why is that?