“As the solar steamer is using steam as heat transfer medium, it is an indirect cooking system. This allows the design of a split system where the thermal solar collector can be placed at some distance (e.g. on the roof) apart from the place of cooking (e.g. in the kitchen). The cook is not exposed to the sunshine and can use the steam at whatever height or location is convenient and culturally acceptable.
This makes it a very convenient cooker for large quantities of food. Using simple stackable steaming pots several dishes can be cooked simultaneously. The steaming process is very similar to traditional steaming processes and should easily find cultural acceptance.
The solar generated steam can also be used to heat large pots of stew or soup by guiding the steam directly into the liquid were it condenses and releases the heat of condensation. This leads to a gentle agitation of the food without burning it.
As can be seen from the sketch above the basic concept is very simple. The solar collector is filled with water. Because of the high efficiency and the good insulation of the evacuated glass tubes the water will start boiling when exposed to sunshine. The steam will be guided to the food steamer using a flexible, steam resistant hose.
The solar steamer can produce high quality distilled water a day (small quantities), pastuerized water (large quantities) from the condensed steam. Solar steam can also be used for sterilization and producing energy.
The Sun2Steam collector can produce steam to cook for about 30 people a day. There is also the cultural advantage that people in Vanuatu don’t mind eating cold food once it has been cooked, so cooking during the day and eating in the evening is no problem.”
Special thanks to Dr. Jo Muller for this tip. http://www.sun2steam.com.au/solarcooker/cooker.pdf