Questionable Solar Dehydrator Physics?

[ChinaVoodoo]

I found this design and I'm curious about the assumption that the hot air will actually flow through the box as diagrammed. Thoughts?

 

[Redleaf]

Not an hvac engineer myself but I would design that differently. Warm air rises is what I learned in my limited education and life experience. Warm air entering the bottom of that outhouse looking building would rise and exit very well. Taking the sloped solar collecter and laying it flat so that heated air could enter the bottom of the building would likely work very well in my humble opinion.

 

[deluxestogie]

If (in the image) there is a pipe on the left (hidden by the open door) which is open to the bottom interior of the chamber, and open to the exterior where the exit arrow points, then I would imagine that the heat differential between the air in the heated panel and the air inside the chamber would create a circulation following all those arrows. It looks like the designer's goal was to get the solar heat, with out the solar exposure to the stuff being dried.

Bob

 

[ChinaVoodoo]

I like this idea because having the dryer behind the collector makes it less top heavy.

 

[deluxestogie]

Community Solar Dehydrator Plans

As interest in home gardening and self-sufficiency surged during the pandemic, many are looking for ways to preserve foods from their newfound harvests. This fact sheet provides an overview of how to build a community solar food dehydrator for food preservation, based on our experience doing so...

extension.usu.edu

 

[Plinsc]

It’s humid here so stacked trays don’t dry as fast or well as a single tray does, to much moisture forced through the trays.

*here’s a link to what I’ve found works better in the humidity

A Radiant Solar Food Dehydrator That Doesn't Fight Physics - GeoPathfinder.com

A Radiant Solar Food Dehydrator That Doesn't Fight Physics - GeoPathfinder.com: One day (in 1985) I needed to dry a bunch of greens and the current solar dryer was full (a couple of handfuls was all it could handle). I had an old window screen laying around and a corrugated metal roof built...

www.instructables.com

 

[deluxestogie]

It’s humid here

A simple differential of 20°F warmer inside the dehydrator compared to ambient will drop the relative humidity by 50%. So the stacked vs flat design is a matter of real estate: sprawling parking lot vs. multi-story parking garage.

Bob

 

[Plinsc]

I didn’t have luck with the stacked, maybe a fan added to the intake would have helped.

*I was trying passive solar in the build of them