Build a solar dryer to keep fruit and vegetables healthy

Solar dryer

Dehydration is a very interesting preservation technique for herbs, fruits and even vegetables. It is the preservation method, excluding lacto-fermentation, which is the healthiest. The vitamins, the active ingredients of the food are preserved, and it is easy afterwards to reconstitute them by soaking them.

* For the racks, prefer tulle

Rather than wire mesh or plastic canvas, tulle is a lightweight fabric suitable for racks.

* Close the air inlets / outlets well

As with the racks, use tulle to cover the vents at the top of the dryer and filter the air inlet (avoid insects).

* Do not use double glazing

A single glazing of 4 or 5 mm is much more efficient.

* Improve performance by modulating the angle of the absorber

We gain by modulating the angle of 45 , from 10 a.m. to 4 p.m. in the middle of summer, an angle of 30  is more efficient (but technically, it is more complicated).

* Ventilate to improve drying

A small fan recovered from a computer and operating at 12 V activates drying by circulating air, which is largely as important as the temperature (ideal between 35 and 50  C).

You can also opt for efficient, silent and permanent ventilation / aeration without any electrical connection with a solar ventilator fan, such as the solar dryer for kava 

* To isolate the back of the sensor

Between two wooden panels, use sawdust, or straw or

* Provide feet or / and casters

Be careful, this dryer can be quite heavy, and if you have to move it, provide good casters.

Jacky for the realization of the dryer and the photographs,

Continued series dryer, summer is past or how to dry right now. Another little technique to get closer to autarky, a dryer with a few pallet boards, and you’re done A few more apples, those that cannot be stored in the cellar. They dry out and will give us some vitamins this winter, we can do the same with pears. we can still dry some nettles too. The design, temperature control and modeling of an indirect solar dryer for kava with oriented air flow are presented. The PV powered temperature control board is made using a thermistor. The drying of nut slices was carried out with and without regulation for the lick, cross and cross airflow mode. The heat balance on each element of the thermal sensor is established based on the heat transfer modes. For an average irradiance of 800W / m2, the temperature of the drying chamber reached 68  C regardless of the type of absorber. This temperature has the same profile for the three air flow modes. The temperature gradient is horizontal for the licking flow, vertical for the through flow and diagonal for the cross air flow. The thermal sensor model has an overall loss exchange coefficient of 2.94 W / m2 /  C, a contact resistance of 0.025 m2  C / W between absorber and insulation, and a speed of air of 0.2 m / s. The synthesized regulator is proportional to the 3  C band. The temperature control in crossed mode presents good drying kinetics

Here is a new manual for the manufacture of a solar dryer. 

Man has always preserved his food in different forms: smoked, salted, lacto-fermented, canned, dried, etc. Sun drying is an easy process to implement and very effective for preserving food and aromatic plants. . It is a gentle drying, to the rhythm of the sun. Drying makes it possible to preserve the surpluses of vegetable crops or the spoils of the pickings in all seasons. By rehydrating the foodstuffs, you will be able to benefit throughout the year from products which have retained their aromas and nutritional qualities.

In this manual, we present to you a compact and removable dryer, adapted to our nomadic life. There are different models of solar drier but the operating principle is always the same: the fresh air enters a thermal collector where it is heated by greenhouse effect between a glass and a black support. The heated air enters the insulated drying compartment and passes through all the drying racks to be extracted through ventilation.

For ideal drying, the temperature must be between 35 C and 45 C and the air in the drying chamber must be dry: while drying, anybody gives off moisture, hence the importance of ventilation that ensures a dry drying compartment. Poor ventilation will affect drying, and temperatures that are too high will destroy the aromas and nutritional qualities of the dried food.