SOLAR FRUIT DRYING
Value Adding
Aftabi Raisins Grower price Aftabi $0.50 to $2.00/kg
Premium 25mm Shundukhani kishmish Kishmish Raisins Estimate is the current market demand for premium kishmish raisins is at least 3 times current Afghan supply. Probably with a high quality kishmish product, new markets could be developed. Premium 25mm Shundukhani kishmish Grower price = $2.00 to $5.00 / kg
Kishmish Khana Tradition Large 30 meter long Kishmish Khana Estimate $12,000 cost to build 13,500kg fresh Shundukhani yield 3,300kg kishmish 13,500 x $0.30/kg = $4,050 cost of grapes 3,300 x $2.00/kg = $6,600 gross 3,300 x $5.00/kg = $16,500 gross Gross kishmish revenue - cost of grapes = added value $6,600 - $4,050 = $2,550 added value $16,500 - $4,050 = $12,450 added value 30 days to dry grapes and traditionally one batch per season
Improved Direct Solar Drying More sanitary Faster drying More productive “Direct” Solar Maybe Kishmish if use p.metabisulfite? “Batch” process
Critical Kishmish Parameters What makes Kishmish raisins? Shundukhani grapes Shade minimal Ultraviolet light Lower temperatures Probably no higher than 38 Celsius Should experiment with potassium carbonate and potassium metabisulfite
Drying can be faster, if: Raisin Production Drying grapes Heat Air flow Relative Humidity Time Drying can be faster, if: Higher temperatures are maintained 24/7 More airflow Grapes are spread in thin layers Some grape treatments are used
Kishmish Khana / Kishmish Konex™? Is Kishmish Khana necessary ? Perhaps containers will be better?
Break & Questions
Technical Raisin Questions Kishmish Raisin Quality If constant 38 Celsius temperature, will quality be same? If raisins are dried faster with more airflow, will quality be same? If grapes are pre-treated to speed drying, will quality be the same? Potassium carbonate Blanch hot water Other
Conventional Dryer with Gas Heat ‘McKenzie’ Dryer 1860kg fresh grape 465kg Kishmish $930-$2325 per load Kishmish Guessing 48 hr per load at 38 Celsius Estimate Cost to run Electric fan = $1.00/hr Gas heat= $5.00/hr $6/hr x 48 hr = $288
Indirect Solar Drying Containers Inexpensive Protects fruit from sun Easy sanitation Easy to modify to create indirect solar dryer 65 Celsius
Solar Container Dryer Estimates Rough estimate: 9,525kg fresh Shundukhani grapes = 2,116kg kishmish With high airflow only perhaps dry in 8 days With high airflow and solar collector with heat storage, perhaps dry in 4 days. 2,100 kg Kishmish x $2/kg = $4,200 in 8 days?
Experiment Proposed Thin layer grapes 80mm tray spacing High speed fan airflow container with solar collector or without
Small Scale Experiment Proposed Small test box could make from wood Thin layer grapes on mesh trays 80mm tray spacing High speed fan airflow Keep grapes in dark ensure fresh ambient airflow How many hours to dry grapes into Kishmish raisins?
Break & Questions
Solar Dryer - only ambient heat Insulated ducting
What is a Solar Collector?
Solar dryer -with collector only
What is Heat Storage?
Solar Collector and Heat Storage
Solar Dryer Workflow Diagram represents a commercial scale indirect solar dryer with energy collector and heat storage.
Solar Container Dryer Estimates Rough estimate: 9,525kg fresh Shundukhani grapes = 2,116kg kishmish With high airflow only perhaps dry in 8 days With high airflow and solar collector with heat storage, perhaps dry in 4 days. 2,100 kg Kishmish x $2/kg = $4,200 in 8 days?
Questions
Summary Anybody want to learn more? Shall we build a small test dryer box? Shall we build a pilot Kishmish Konex™?