Two identical solar crop dryers were constructed, with one serving as the control and the other for testing the solar concentrator. Drying trials using Roma tomatoes with initial moisture content of approximately 90% were conducted in Davis,California (38° 32′ 42″ N/121° 44′ 21″ W) in various climatic conditions throughout the summer and fall. Tomatoes were considered dried at 10% moisture content. Temperature, relative humidity, and solar radiation were measured outside as well as within each of the dryers to determine how the addition of a solar concentrator can affect the drying rate of tomatoes in solar crop dryers. The concentrator proved to be effective, reducing drying time by 21% in addition to increasing internal dryer temperature and reducing relative humidity. An additional
study on the quality of the fresh and dried tomatoes found that the pH, titratable acidity, color, Brix, lycopene,
and vitamin C determined there was no significant difference in quality between tomatoes dried with and without the concentrator.