food preservation

Household Food Dryer

[preserving <10 kg vegetables, fruit, meat, and herbs using the energy of the sun]

[Summary & Motivation] [Community] [Specifications] [Issues] [Contacts] [Diagrams / Pictures]

Summary & Motivation	Project Initiator: ATS Start Date: Approximately 1991 Projected Completion Date: Two different types being manufactured Current Status: Production and sales Even when a farmer in rural Lesotho manages to grow a surplus of food, it is difficult for him or her to get it to the city markets or to save it for his or her personal use without it spoiling. Preserving the food by drying it is becoming increasingly popular as Basotho realize that the dried product can be sold at a significant profit. Small household solar dryers are the ideal solution for Lesotho, considering the country receives more than three hundred days of sunlight per year. The solar dryer has undergone several modifications from its original inception in 1991. The size has been increased, the movable vent strip on the back has been removed, holes on the sides have been sealed, and screens have been added to prevent insects from entering. [top]
Community	The household solar dryer is sold mainly to women who want to preserve their surplus crops. Currently, the larger, single-tray model with a fiberglass lid is being sold for ZAR 385 (Approximatelty $60), even though the material cost is almost $100. Because of ATS's dedication to alleviating the problem of rural poverty, the group is currently subsidizing the cost of this solar dryer. The more recently developed double-tray model with a glass lid is also a large seller, but the material cost is slightly higher than that of the other dryer. [top]
Specifications	Reaches temperature of 60-70 degrees Centigrade Allows proper air flow to prevent food items from turning black Prevents flies and insects from entering Requires three days to dry food in winter sun, and two and a half days in summer sun Can be lifted and moved by women [top]
Issues	While the solar dryer is currently being sold on the market, ATS is constantly looking to improve performance while trimming costs. There are several areas on which small innovations could dramatically reduce cost. Help is needed in the following areas: Developing a new top cover, currently one of the most expensive components. It has been proposed to engineer a plastic film cover which would maintain drying performance while reducing weight and cost. (Perspex has been rejected because of high cost) Analyzing thermal fluids to determine required heat transfer characteristics of unit. Reduce cost of entire unit so that profit margin exists. Standardizing production using jigs. [top]
Contacts	Project Leader: Lengeta Mabea MIT Contact: Amy Smith <bee17@MAC.com> ATS Contact: Lengeta Mabea <mabeald@Yahoo.com> Website (If applicable): N/A [top]
Diagrams / Pictures	DIAGRAMS Description (Name) [Date] Download Modern Version Dimensioned three-dimensional model of household solar dryer. Done in English units although actual unit was constructed using SI units (M. Zedler) [8.28.2005]. *.zip (0.63 MB) 1991 Drawings Original hand drawings for solar dryer developed in 1991. Series of labeled *.jpg pictures. Borrowed from ATS shop, which explains well-used condition (N. Malikhetla) [6.1991]. *.zip (12.5 MB) 1991 Model Solidworks model of dryer based on actual plans from 1991 (Model not being used by ATS currently) (M. Zedler) [8.30.2005] *.zip (0.93 MB) PICTURES Description (Name) [Date] Download Household Food Dryer Photo Album Several pictures of the household solar dryer with captions. *NOTE: Going to album will take you away from MIT-ATS site. Please bookmark so that you can return easily* (ATS / M. Zedler) [8.31.05] *.html (Link) Solidworks Model (Modern) Pictorial rendering of Solidworks model available above. Isometric view. Click on thumbnail for bigger *.jpeg picture (M. Zedler) [8.31.05]. Solidworks Model (1991) Pictorial rendering of Solidworks model available above. Isometric view. Click on thumbnail for bigger *.jpeg picture (M. Zedler) [8.31.05]. [top]

*.pdf - Portable Document File / *.doc - Document (Microsoft Word) / *.jpg - Joint Photographic Experts Group (Browser) / *.zip - WinZip Compressed File (WinZip)

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