Food Quality Magazine Jan. 2016 Issue 1 (P.16)
The benefits of using solar energy in the processing of food products is gaining traction in both the agricultural community and with end-use consumers who ascribe a premium to such products.
Solar air heating systems are used in different configurations around the world to produce hot air that can be used for space heating or for process heat purposes. This specific use – solar process drying – is becoming more popular in the agricultural community as it provides a clean energy solution to producing high quality food products.
Consider that many of the world’s most important crops need to be dried to remove moisture as part of the production process. Removing the moisture from crops such a coffee beans, tea leaves, cocoa, nuts, fruit, rice, spices, corn, etc. is an essential process that helps transform the raw goods into the final product. It is also extremely resource intensive when using mechanical drying methods that rely on wood, propane or oil. In more traditional drying operations, it is common for produce to be passively air-dried in the sun, which takes significantly longer than mechanical drying and can lead to a higher rate of spoilage, mycotoxins and uneven moisture levels.
Incorporating solar air heating into a drying operation produces a double-benefit in terms of improving both the process of drying and the final product. The solar technologies can heat large volumes of incoming air up to 55°C (100°F) above ambient, making it ideally suited for many crop drying applications. The solar air heating system may provide all of the heat during a sunny day or act as a pre-heat during cloudy conditions. Typically solar air heating systems operate as a pre-heat to traditional mechanical operations where it can be easily incorporated into tunnel, trough or conveyor dryers.
In both cases it substantially reduces the dependency on traditional fuels which has a myriad of positive effects, including:
- lower operating costs;
- decreased reliance on fuels that need to be transported to remote sites;
- counteracting deforestation by reducing the quantity of trees that are harvested for fuel;
- lower humidity in the incoming air (because it is heated before entering the building or drying chamber) which means that the air has been preconditioned to absorb more moisture;
- GHG emission reductions; and
- producing a high quality finished product that is eco-friendly and was processed using “clean & green” energy
Solar air heating systems may also reduce or eliminate poly-aromatic hydrocarbons (PAHs) created by displacing conventional fossil fuels used in active drying systems.
Solar air heating systems have been used on hundreds of agricultural and animal buildings for poultry ventilation, hog ventilation, and other forms of livestock ventilation. Animal barns not only need to maintain a very warm indoor air temperature (up to 30 C is common), but they also require continual ventilation air. This typically produces enormous heating bills, especially considering that many farms and nurseries use propane to heat the incoming air. (And maintaining proper ventilation is crucial in the production process because clean air is so essential to the health of the animals.)
To help agricultural and food producers promote and publicize their use of solar heating in the processing of their products the Solar Air Heating World Industries Association (SAHWIA) embarked on a program of creating the “Solar AiR Logos” which were unveiled in December 2015.
The Solar AiR logos are the first global consumer label that identity companies and farming entities that have incorporated solar air heating in their operations. The Solar AiR Logos are intended to inform consumers about the use of solar air heating in the drying and processing of food products. They will also promote the multitude of benefits possible from solar heating and speak to the 360 degrees of sustainability that is possible with solar air heating in any business or agricultural operation.
The Solar AiR logos will allow these companies that produce solar dried fruit, coffee, tea, nuts, herbs, and other food products to proudly display their commitment to sustainability and carbon reduction on their product packaging and in their promotional material. It will also provide consumers with a choice to favor those foods and products that are dried and processed using solar.