Question

What are the modes of heat transfer employed in solar drying systems?

(a) Radiation and convection

(b) Conduction and convection

(c) Conduction and radiation

(d) Radiation and conduction

I have been asked this question by my college professor while I was bunking the class.

The doubt is from Sun Drying topic in chapter Drying of Food Processing Unit Operations

Answer 1

The correct answer is (a) Radiation and convection

The best explanation: Solar drying systems can be categorized mostly on the basis of the mode of transfer of heat engaged. These are radiation and forced convection. Drying is a twofold process which includes 1.The heat transfer to the product from a heating source and 2.Mass transfer of moisture from the interior of the product to its surface and from the surface to the surrounding air.