Download complete project materials on Design And Construct A Solar Food Dryer Project from chapter one to five with reference
Drying process is the most common form of food preservation and extends the foods shelf life. It is a simultaneous heat and mass transfer operation in which moisture is removed from food material and carried away by hot air. (Boiln and Sakunkhe 1982). A solar heating system is used to increase the thermal storage inside the sola dryer during the day or to transfer excess heat from inside the drier to heat storage area.
Dehydration is a common technique for preservation of agricultural and other product, including fruits and vegetables. (Narinsesingh and Mohammed, 1988).
Solar dryers have advantages over sun drying when correctly designed. They give faster drying rates by heating the air to 10-30oC above ambient, which causes the air to move faster through the dryer and reduces humidity.
Drying is an excellent way to preserve food and solar food dryers are an appropriate food preservation technology for a sustainable world. Actually, solar food drying is one of the oldest agricultural techniques related to food preservation but every year, millions of dollars worth of gross national products is lost through spoilage. Reasons include;
Ignorance about preservation of produce.
Inadequate transportation system during the harvest season (mostly climate related).
The low price the low price the rural farmer receives for products during the harvest season (Samuel, 2011).
Drying of crops can change this trend and is useful in most areas of the world, especially those without a high humidity during the harvest season. If drying of produce were widely implemented, significant saving to farmers would be achieved. These savings could help strengthen the economic situation of numerous developing governments as well as change the nutritional condition in these same countries
Drying generally refers to the removal of moisture by evaporation rather than by pressure or other physical means. The factories that are affecting the drying can be identified as the temperature, humidity, pressure, velocity of air, size and shape of the wet surface and the air movement with respect to it.
There are various mechanical drying methods that are available at presents. Some of this are operating utilizes fans for air circulation, and electric or gas heaters for heating or drying air. But they are very expensive drying methods. So we have introduced a high efficiencylow cost vegetable dryer for our future use.
1.1 AIMS: To design and construct a solar food dryer.
- To provide a method of preservation which will reduce the greater risk of spoilage and adverse climate condition like rain, wind, moist, dust e.t.c. and lost of produce to birds, insect and rodents.
- To compare the temperature generation between a single and double screen collector.
- To compare the ambient temperature with the temperature of the enclosure.
1.3 JUSTIFICATION: The idea of solar drying technique is to come up with an alternative option to direct sun drying. Dehydration of open air sun drying is not satisfactory due to the product deteriorate rapidly. Studies shows that food items dried on solar dryer will be superior to those which are sun dried when evaluated in terms of taste, colour, flavor and nutritional value. And to improve on the previous construction and experiments carried out on solar dryers.
Previous works has been done on the single screen type. So the project is set to compare it with temperature generation using the double screen collectors.
1.4 LIMITATION: The problem associated with using solar energy is that availability varies with time. The variation is as a result of day- night cycle or seasonal variation due to orbiting of the earth, and location due to local weather conditions.