Here are some plans I found.

http://www.builditsolar.com/Projects...r%20AEnL55.pdf

Solar Dehydrator Plans.pdf | Peace Corps Burkina Faso

http://pdf.usaid.gov/pdf_docs/PNABC941.pdf

http://www.burlingtonpermaculture.or...dehydrator.pdf

A general info pdf on drying

http://www.cals.uidaho.edu/edcomm/pdf/PNW/PNW0397.pdf