GO-DECK (Global Off-the-Grid Duralast Evaporative Cold Keepers) The ‘GO-DECK’ Team: Dr. Ronald Fritz Mentor David Oliveira Singapore Talar Terzian USA Suganth Kannan USA Belinda Baraka
Introduction Food loss from lack of cold storage is a major problem in many parts of the world. Over 600 million people in sub-Saharan Africa lack access to electrical power and refrigeration. Unlike many other parts of the world, where consumers waste the greatest amount of food, the largest amount of food loss (more than 40%) in Africa happens during the time frame, post-harvest to consumption. Zeer pot technology is cooling without Outer clay pot electricity, placing one clay pot inside another separated by wet sand, making the inside of Inner clay pot the inner pot cool via evaporation on the Sand outside of the outer pot. Please refer to the Reference List for cited sources Stored Veggies Wet cloth Water Heat transfer Water evaporates
Drawbacks and Inspiration Zeer pots are heavy (over 100 lbs. ), fragile if moved, and are costly in many parts of the world. This inspired the team to develop a non-electrical fridge based on evaporative cooling, one which is built entirely of readily available landfill bound materials, light weight, durable, and efficient.
Hypothesis If evaporative cooling technology can be utilized to build a lightweight, off the grid Food Logistics System, out of recycled materials bound for landfills, creating a significant inner temperature drop, enabling longer shelf life, reducing malnutrition coupled with economic savings, then hundreds of millions of GO-DECK users will promote food waste reduction during the postharvest to market journey.
Scientific Rationale for this Study 1. Fruits and vegetables are living organisms that once picked start on a steady path of deterioration. 2. This decay is a race against time as humidity and temperature actively work against the produce’s biological clock. This occurs thru a process called respiration which actively uses up the produce’s stored energy. This is the prime perpetrator of produce food loss. 3. Since produce has a naturally high water content, its moisture must be maintained in order to reduce this decay. Storage and transport of produce at high levels of humidity (90%+) maintains adequate moisture levels to maintain freshness for the longest period of time. 4. Thus, humidity and temperature are directly related to the shelf life and apparent freshness of fruits and vegetables. By controlling the conditions of these two critical elements we can greatly reduce food loss due to factors of decay. Doing so in a non-electric way brings these benefits to millions who do not have or cannot afford electricity.
Defining the Design Criteria To convert our hypothesis into a practical design, keeping end user desires in mind, we conducted a survey of potential Tanzania end users. Their needs, ideas & concerns were the basis for our design approach. Questions/responses are shown below: Q 1 What will be an Ideal size of non electric cooler for use? 2 x 2 x 2 feet 2 x 4 x 2 feet 4 x 4 x 2 feet Responses 13 10 13 Q 2 Q 3 How many times a week do you go 2 market 2 buy vegetables? One Two Three Four Five How do you travel to market? Walking Tricycle Dalla - Dalla Responses 14 6 3 5 9 Responses 19 2 16 Q 4 How much time do you take to reach the market? 15 minutes 30 minutes 60 minutes 120 minutes Responses 23 10 3 1 Q 5 If we design a similar system for you to carry vegetables to market, what size you would like to that to be? 2 x 2 x 2 feet 2 x 4 x 2 feet 4 x 4 x 4 feet 6 x 4 x 4 feet Responses 4 6 10 14 Q 6 How much are you willing to pay to get non electric coolers for your family? 500 Shilling 1000 Shilling 1500 Shilling 2500 Shilling Responses 6 7 7 16 Q 7 Cooler will provide 15 to 20 degree drop in temp from outside of the cooler to inside. Do you think this will be beneficial for your family? Somewhat beneficial Beneficial Really beneficial Responses 11 10 15 Q 8 Tell us a few words about the non electric cooler idea? Will save my family Help me buy vegetable for the week and save money Solar dried vegetable will have better shelf life It is wonderful really helpful Amazing invention. Will help people. It is awesome and usable. . . I can’t wait!! Awesome project Just go on. The best idea the cooler with no use of electricity Perfect and best idea for African families including mine. Best idea am looking forward to see it in Tanzania CLICK ON THE PICTURE FOR COMPLETE SURVEY RESULTS
Survey Driven Design Criteria Based on survey results, along with direct interviews with local farmers and team brainstorming, we defined the following design parameters: 1. To design a unit that reduces food loss due to exposure to ambient heat, humidity fluctuations, and outside debris. 2. To design a low cost unit (under $8 in Tanzania) that would be built out of repurposed materials, preventing overload of landfills. 3. To design a unit that would work without electricity. 4. To design a mobile, modular, stackable, compartment oriented, lightweight (less than 40 lbs) device that would mount on a pull cart, or travel on a Dala dala (mini bus). 5. To design a more durable unit than a Zeer pot, made out of plastic crates instead of clay that could be scaled up in size. 6. To design a unit that would reduce trips to market by prolonging the freshness of produce by 2 -3 days.
Method – Conceptualizing the Design In order to address the needs identified by the survey, our team spent many hours discussing the results, and brainstorming possible evaporative cooling solutions to meet the needs of our end users. The ‘aha’ moment came when we figured out how to make this evaporative device lightweight, portable, and out of landfill-bound materials. After many iterations, we settled on one simple, functional, yet elegant design. Concept Model
Method - Proof of Refined Design Our ‘final’ version was built using a 13 x 13 inch recycled plastic milk crate as an outer shell, lined by 1 inch open-cell recycled foam on the sides, and a 1. 5 inch open-cell foam bottom. The inside was then filled with 22 lbs. of blended coarse and fine sand to enhance water retention and evaporation. A deep pail ‘perishable container bin’ was buried in the sand, and was covered by a snug Styrofoam lid. An optional travel, debris prevention, wrap was also made of recycled cloth.
Method – ‘Early on’ Design Iterations Tested This design, targeting our end users’ needs, was the culmination of several design iterations, where overall device performance was evaluated. (CLICK HERE for the preliminary test data) KEY VARIABLE ELEMENTS ARE: • • The impact of different foam types on evaporation The effect of wind or air flow on the rate of evaporation, and internal temperature and humidity levels The impact a constant water drip system has on humidity Total device weight change as an indicator of evaporation rate The effect of different sized and shaped perishable bins on internal temperature and humidity levels The impact of temperature of initial water charge on cooling potential The effect of a Dri-Fit fabric liner on the rate of evaporation
Method - Refined Concept Testing Our Final Concept Model was then ‘replicate’ tested (4 tests for each of the 8 combination of settings used) for 48 continuous hours: • Ambient temperatures of 85°f and 95°f • Ambient humidities of 30% and 65% CLICK ON THE PICTURE FOR COMPLETE DATA COLLECTION TABLES • Wind of 0 mph and 8. 2 mph (which proved to be inconsequential) Also, some non-repeated tests of significance were performed to assess device robustness to certain key variables: • Initial water charge temperature effect on internal cooling over time. (found negligible) • Impact of food (spinach) stored in perishable inner bin on interior temperature and humidity over time. (found negligible) • Effect of various lid type materials (open cell foam vs. Styrofoam) on temp. and humidity levels. (found negligible. )
Test Results 85°f Ambient Temp, 30% Relative Humidity, No Wind: 95°f Ambient Temp, 30% Relative Humidity, No Wind: Under 85°f & 95°f Temps & 30% humidity, repeated trials (n=4) showed fast and sustained cooling with a 2 liter ‘charge’, averaging > 20°f below ambient with stable humidity >= 90%.
Test Results 85°f Ambient Temp, 65% Relative Humidity, No Wind: 95°f Ambient Temp, 65% Relative Humidity, No Wind: Under 85°f & 95°f Temps & 65% humidity, repeated trials (n=4) showed fast and sustained cooling with a 2 liter ‘charge’, averaging ~ 20°f below ambient with stable humidity ~ 90%.
Test Results Summary & What They Mean For environments >= 85°F and <= 65% humidity, on a single 2 liter water 'charge, ‘ performance has been found sustainable for 48 hours: What is achieved in testing? Sustained 20°f cooling relative to ambient temperature What benefit this produces? For every ten degree increase in temperature the rate of respiration is doubled or tripled, thus a 20 degree reduction in temperature would quadruple or in some cases sextuple the shelf life depending on the type of produce (http: //www. postharvest. com. au/Shelflife. PDF) And sustained humidity >= 90% Sustained humidity above 90% impacts the appearance, freshness, and nutritional value of produce and more than quadruples the shelf life of many vegetables (http: //www. deltatrak. com/produce-shelf-life-issues-and-extension -methods-from-harvest-to-retailer) NOTE: Non-repeated tests suggest the above performance can be maintained for 72 hrs.
Global Impact Potential of GO-DECK Performance • According to a Washington Post article, 1. 3 billion people live in the dark including 75% of the Tanzanian population. Seven out of 10 people in sub-Saharan Africa live without reliable access to electricity or refrigeration. • According to a joint study by SIK and FAO entitled Global Food Losses and Food Waste, the majority of food loss in sub-Saharan Africa takes place during the production to retailing phases where 170 kg/year per capita is lost. Using GO-DECK: Assuming 170 kg for each of 900 million people, that equates to 153 million metric tons of food loss per year. If just 1% of that could be reduced due to the shelf life extending abilities of GO-DECK (which we think is possible) 1. 53 million metric tons of food per year would be saved.
GO-DECK Summary • GO-DECK (Global Off-the-Grid—Duralast Evaporative Cold Keeper) is a non-electric, evaporation based, storage and transportation system that we have shown to be ready to increase shelf life by days for millions of people in developing nations worldwide. • GO-DECK offers durability, flexibility and scalability (see the team’s roll out vision on slide 18) • GO-DECK utilizes recycled crates lined with open cell packing foam, a recycled plastic/metal food container along with sand water to provide this unique evaporative cooling technology. This is the closest to the “ultimate green machine. ” • GO-DECK’s use of nearly free, landfill-bound materials provides an economical cooling option for millions that prevents food loss due to longer shelf life, less waste, and other important financial savings throughout the supply chain. CLICK ON THE PICTURE FO STEP BY STEP BUILD INSTRUCTIONS
Key Learning Points As evidenced by our research, data, and analysis: • GO-DECK reduces perishable storage and transport temperature by 20 degrees F. • GO-DECK provides the perishables it transports and stores at a constant 90%+ humidity • Under wind conditions of 8 MPH, GO-DECK offers protection from dirt and debris as well as excess airflow into the perishable chamber by providing an optional cloth shield or wrap. • GO-DECK without the addition of multiple water charges was able to keep temperatures at 20 degrees F below ambient and maintain a relative humidity of 90+ for 48 to 72 hours. • Trials of auto drip water systems demonstrated that these desirable conditions could be maintained for long times (indefinitely). • Results from initial testing of an open-cell foam lid with an auto drip water system were positive suggesting an even greater potential for evaporation with this addition • The mixture of fine to coarse sand proved pivotal in the unit’s ability to hold a water charge with minimal leakage and to its ability to enhance evaporation.
Roll Out Vision of Our Team • We were challenged to reduce food loss. In response to this we have designed, developed, tested, collected data on a real world solution. CLICK ON THE PICTURE FOR VIDEO FROM TANZANIA • We are now providing this to the forum looking for support to help carry out OUR vision to roll out first phase in Tanzania in 2016 and then to other parts of Africa before the end of 2017. • Building instructions for our GO-DECK system are currently available on our website. We are looking to partner with NGO’s on the ground to disseminate this information (as internet access is so limited in developing nations). • We seek to develop scaled up plans for larger versions for market-based use by vendors. • We also seek sponsorship for mass production of inexpensive ‘ready made’ units to be distributed in selected towns across Tanzania. • We are looking forward to guidance from the judges, Global STEM Alliance, NYAS and Challenge Sponsors regarding how to roll out our breakthrough technology to maximize its benefit and contribution to mankind.
As we further considered the needs of our target audience and began to see that they not only needed a device that would cool down their produce and allow them to take it to market, but also a unit that would hold the harvest on the farm until parts were needed to be transported to specific markets; that further brought up the need for a large unit to be waiting for them at the market upon arrival to receive their goods and continue to keep them cool. The GO-DECK system is not only a small storage crate system that allows for specific produce to be
References • http: //www. fao. org/fileadmin/user_upload/suistainability/pdf/Global_Food_Losses_an d_Food_Waste. pdf • http: //data. worldbank. org/indicator/EG. ELC. ACCS. ZS/countries? display=map • http: //www. mapcruzin. com/free-maps-africa/africa_veg_86. jpg • http: //www. fao. org/wairdocs/x 5403 e 08. htm • • http: //web. worldbank. org/WBSITE/EXTERNAL/COUNTRIES/AFRICAEXT/0, , content MDK: 21935594~page. PK: 146736~pi. PK: 146830~the. Site. PK: 258644, 00. html http: //www. frontlineservices. com. au/Frontline_Services/Storage_temperatures_for_fr esh_produce. html • http: //pubs. acs. org/doi/abs/10. 1021/bk-1981 -0170. ch 008 • http: //ijettjournal. org/2015/volume-23/number-6/IJETT-V 23 P 254. pdf • http: //www. deltatrak. com/produce-shelf-life-issues-and-extension-methods-fromharvest-to-retailer • https: //www. washingtonpost. com/graphics/world-without-power/ • http: //www. postharvest. com. au/Shelflife. PDF • Agriculture and Natural Resources Publication 21614, University of CA
We would like to take this moment to thank: Global Stem Alliance Junior Academy administration New York Academy of Sciences Challenge Sponsors Our beloved Mentor Dr. Ronald Fritz Our parents Farmers of Tanzania All our JA classmates
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