Heat recovery ventilator in my Scamp 13

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Sharpscamp
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Heat recovery ventilator in my Scamp 13

I am fairly new to the Scamp camping.  I bought my new-to-me 13 ft Scamp in 2021 and have camped 73 nights, mostly traveling in the day and staying in parks or at Walmarts or Cracker Barrels at night.  Most of the time I camped in cooler climates with temperature ranges from low 20’s to mid 40’s at night and the moisture accumulation in the closed up Scamp was a problem.  The simple solution is open a window, but of course the cold air is also a problem.  I have installed heat recovery ventilators in my home and realized such a device would be useful in the Scamp to provide fresh air during cold weather and eliminate the moisture without the input of cold air.

I searched for a ventilator that would use a small amount of power and fit in the confines of the Scamp but found none commercially available.  I came across a DIY experimental design that was made from a combination of plastic plumbing pipe and 3D printed parts that looked promising.   It is a counter-flow design so high efficiencies are possible.  I designed and built a prototype version that fits inside one of the benches in my Scamp.   After installing it I spent 3 weeks on the road with most nights being in the 30’s and low 40’s.

The results are very encouraging. With all windows closed at night I had zero accumulation of moisture on the windows and bedding and the ventilator brought in fresh air at virtually the same temperature as the the interior of the Scamp, about 65 degrees, regardless of the outside temperatures.  The air flow in and out is about 2 CFM which exchanges the air in my 13 about every 2 hours.  The fans draw less than 1/2 amp so battery drain is minimal.  I am working on version 2 which will provide more air flow, hopefully about 4 CFM, and also hopefully without reducing the efficiency.

I am interested in suggestions or questions about my system.  It may or may not be commercially viable but its an option I am considering.  The parts are either off the shelf items or 3D printed parts.  3D prints are time consuming but inexpensive as a DIY so I suspect most interest may be from those who can build and install it themselves.  As version 2 progresses I can post up photos of the install if there is interest.

Mark

scamp01 (not verified)
Great idea! I like your truck

Great idea! I like your truck.

Gloria
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Game changer!

I don't have a 3d printer, nor do I have access to one. I would definitely consider buying such a ventilation system from someone. I think this is something you may want to pursue as a commercial venture. Great idea!

Gloria

Sharpscamp
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ventilator pictures soon

Thanks Gloria.  The ventilator sure made my nights more comfortable.  I will be posting pictures as I build and install the 'version 2' in the next few weeks.  Stay tuned.

Mark

Mark

Mr.T
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I'm interested, looking

I'm interested, looking forward to reading about version 2, thanks!

Sharpscamp
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Heat recovery ventilator installed

The version 2 of my heat recovery ventilator is completed.  The flow rate is 3 CFM so I did not reach my goal of 4 CFM.  The space available is very limited so in order to increase flow I would have to use larger or more powerful fans.  These two fans only draw about .3 amps combined and the noise is barely audible.  At this point I am satisfied with the install and will wait for cold weather to do more testing.

 

I installed the ventilator in my Scamp 13.  These first four photos show a little about the design and of the space where it is installed.  The housing parts are 3” s&d PVC pipe and fittings from Lowes.  The adapter parts to connect the fans and flexible ducts to the pipe are 3D printed.  The heat exchanger core is made from 52 drinking straws 75 cm (29.5”) long sealed at each end with a printed part to separate the stale exiting air from the fresh incoming air.

 

 

 

Mark

Sharpscamp
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HR vent installed

These photos show the final installation in my Scamp.  It is well packed into the space available but everything fits.  I will be installing a turn lock connector for the AC cord so it will not be interfering with the ventilator system.  Now just waiting for cold weather in Oklahoma to test this version.

I welcome any comments or suggestions.  Thank you for your time.

Mark

Sharpscamp
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test results

Here is information to close out this discussion.   There were two days in November that I camped and the outside temperature dropped to less than 28 degrees.  With the second version ventilator as pictured above, I had a little over 3 CFM flow in and out.  I kept all windows closed, so the only ventilation was through the HRV (heat recovery ventilator).  With thermostat set to maintain 65 degrees and outside temperature below 30 degrees, the furnace cycled about every 13 minutes and stayed on for 3-4 minutes at a time.  The incoming fresh air temperature from the HRV vent was raised to about 55 degrees.  Not real warm but certainly warmer than leaving a window open for ventilation.  

I had no condensation on any windows and the humidity did not change appreciably inside the Scamp.  In my previous experiences in cold weather camping with windows closed and without the HRV, there would have been high humidity and a lot of moisture condensed on windows.  My main disappointment was the fresh air coming in was only raised to 55 degrees.  Version 1 raised the incoming fresh air temperature to within 2-4 degrees of the inside ambient temperature.  I suspect that the increased flow rate reduced the heat transfer to the incoming fresh air.  

All in all, the test was marginally successful but I plan to clean up the version 1 HRV and re-install it. Even though it only flows 2 CFM it was more comfortable with the incoming air temperature only 2-4 degrees less than the ambient in the Scamp.  In addition to maintaining healthy ventilation, the HRV allows me to keep a warm temperature inside while reducing the run time of the furnace which saves propane and increases the time I can camp without charging the battery.

Mark

Out4Fun
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Quite impressed

Thanks for sharing your ingenuity and test results. I would definitely be interested in a model for purchase as I have no access to or familiarity with a 3D printer. 
Nancy

Sharpscamp
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Heat Recovery Ventilator

Thanks for your interest.   I do not know yet if I will pursue making the HRV for sale.   Certainly more testing is needed to provide reliable information on its performance.  I will post up if it looks favorable.

Mark