I hope you are doing well and you and your family are staying safe.

Please find below the energy savings using a transpired solar air heating collector to dry your food. Your kWh/m2/Day may be higher in your area making your payback even better.  Please keep in mind your operation cost.

I lowered the kWh/m2/Day to 4.5 kWh. Estimations on how much energy you could save per year. Being unsure of what you are paying per kWh or for propane or oil but you can change the numbers based on what you are paying.

Any Investor would give there right arm to get a 50% per year return on their investment. Even a 25% return on their investment per year is huge.

Here would be the best option for solar drying. It uses a transpired solar air heating collector 34 m2 area with 2 solar electric modules to run the fans during the day. The transpired solar heating air collectors are about 50% efficient. P,V. modules are 18%, I oversized the P.V. modules to charge a battery so you should get a solid 10 hours of solar drying time and get the job done in 1 solar day. Solar Air Heating collectors use the latest technology called (Transpired Solar Air Heating collector) they are un-glazed solar collectors and proven to offer the highest efficiency at a low price. As a result the air temperature will be perfect for you to get a quality dried product.

(Note) It is very important to slice to fruits and vegetables at the same thickness, there are many devices that can do this. It is not recommended to use your eye to gauge the thickness. The reason being that even thickness is important is if you have a slice at 1/8” thick vs. 1/4 thick the 1/4 thick slice will have twice as much thus take twice as long to dry.  

Payback with using a solar system over using propane or electricity.

Based on Solar Radiation of 4.5 kWh/m2/Day (With being unsure of what your solar radiation level is where you are). A 34 m2 transpired solar air heater collector will collect an average of 76.5 kWh per day, solar thermal heat.

Here below is an approximate energy saving based on what you would pay for electricity from the grid, Propane, Diesel if burned in a generator.

Electricity @ $.25 cents per kWh. – A 34 m2 solar air heating system will collect approximately 76.5 kWh/Day x $.25 cents per kWh = $19.12 per day x 365 days per year = $6880.62 savings per year.  

Propane @ $4.00 per gallon burned in a 94% efficient furnace. – A 34 m2 solar air heating system will collect the equivalent of approximately 1108.45 gallons per year. 1108.45 x $4.00 per gallon = $4433.83 savings per year.  

Diesel Generator: 40% efficiency, 4.5 gallons of diesel to generate 76.5 kWh, A 34 m2 solar air heating system will collect the equivalent of approximately 4.5 gallons x $4.00 per gallon = $18.00 per day x 365 days per year = $6570.00 savings per year.  

Thank you!   Stay safe and have a nice day, Paul