User Experience Evaluation and Qualitative Demand Analyses of the Second-Generation (Beta) Prototype of the Portable Shallow- Bed Batch Maize Dryer

Transcription

1 User Experience Evaluation and Qualitative Demand Analyses of the Second-Generation (Beta) Prototype of the Portable Shallow- Bed Batch Maize Dryer AflaSTOP: Storage and Drying For Aflatoxin Prevention 1

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3 Prepared by: Marius Rossouw Design Engineer In collaboration with: Sophie Walker Project Manager catapultdesign.org Billions of people lack access to life's basic needs. We design and implement human-centered products to help them thrive. This work was carried out as a partnership between Catapult Design and ASI through the AflaSTOP project to identify potential drying technology suited to support post-harvest handling devices for maize smallholder farmers. Last updated: 5 May 2015

4 TABLE OF CONTENTS 1. Background Field Testing Objectives and Methodology Testing Objectives Methodology Research Methods Schedule, Location and Environmental Conditions The Dryer s Operating Principle Dryer Configurations, Performance and Operating Cost Breakdown Power and Shallow-bed Configurations Performance Evaluation Performance test weather conditions Performance test drying results Drying performance discussion Operating Cost Discussion Transportation of the dryer to the client Labor costs associated with operating the dryer Fuel cost associated with running the furnace/hx power source Fuel cost associated with firing the furnace (maize cobs) Equipment maintenance cost User-Experience Assessment Testing participant profiles End-user (operator) profiles Primary beneficiary (Farmers) profiles User-experience assessment (Device) Transportability Design recommendations and possible next steps Deployment Operation Teardown and demobilization Qualitative Demand and Willingness to Pay Assessment End-users (Operators) Primary Beneficiaries (Farmers) Conclusion...17

5 Appendix A Alpha Prototype vs. Beta Prototype Comparison... Appendix B Power and Shallow-bed Configurations and Material Breakdown... Appendix C Performance Test Graphs.. Appendix D Testing Participant Profiles Appendix E Manufacturing Requirements and Capabilities... LIST OF FIGURES Figure 1: Dryer operating principles... 3 Figure 2: Power 1 and Shallow-bed 1 Configurations... 4 Figure 3: Power 2 and Shallow-bed 2 Configurations... 5 Figure 4: Cob preheating/drying basket...13 Figure 5: Power Configuration 1 of the dryer beta prototype...20 Figure 6: Power Configuration 2 of the dryer beta prototype...21 Figure 7: Power Configuration 3 of the dryer beta prototype...22 Figure 8: Shallow-bed Configuration 1 of the dryer beta prototype...23 Figure 9: Shallow-bed Configuration 2 of the dryer beta prototype...24 Figure 10: Test 1 - Ambient Air vs. Drying Air vs. Maize Temperature (ºC) P 2, S Figure 11: Test 2 - Ambient Air vs. Drying Air vs. Maize Temperature (ºC) P 1, S Figure 12: Test 1 - Variation in Grain Temperature (ºC) vs. Moisture content (%) P 2, S Figure 13: Test 2 - Variation in Grain Temperature (ºC) vs. Moisture content (%) P 1, S Figure 14: Test 1 - Moisture Content (%) reduction over Time (Hours) P 2, S Figure 15: Test 2 - Moisture Content (%) reduction over Time (Hours) P 1, S Figure 16: Test 3 - Moisture Content (%) reduction over Time (Hours) - P 2, S Figure 17: Test 4 - Moisture Content (%) reduction over Time (Hours) P 1, S Figure 18: Test 5 - Moisture Content (%) reduction over Time (Hours) P 2, S Figure 19: Agricultural service equipment...33 Figure 20: Agricultural service equipment fabrication...33

6 LIST OF TABLES Table 1: Power and Shallow-bed configuration test pairing... 5 Table 2: Weather conditions for each drying test... 5 Table 3: Drying performance test results for each drying test... 5 Table 4: Power source fuel operating cost during testing (for the Kenyan audience)... 8 Table 5: Farmers moisture content assessment...16 Table 6: Dryer beta prototype Power Configuration 1 material breakdown...20 Table 7: Dryer beta prototype Power Configuration 2 material breakdown...21 Table 8: Dryer beta prototype Power Configuration 3 material breakdown...22 Table 9: Dryer beta prototype Shallow-bed Configuration 1 material breakdown...23 Table 10: Dryer beta prototype Shallow-bed Configuration 2 material breakdown...24 Table 11: Prototyping vs. production cost comparison...24 Table 12: End-user (Operator) profile breakdown...30 Table 13: Primary beneficiary (Farmer) profile breakdown...31 Table 14: Dryer beta prototype Shallow-bed fabrication requirements and Jua Kali capacity...32

7 1. Background The AflaSTOP: Storage and Drying for Aflatoxin Prevention (AflaSTOP) project is identifying the most promising storage options to arrest the growth of aflatoxin and designing viable drying options that will allow smallholder farmers to dry their grain to safe storage levels. The project works to ensure that businesses operating in Africa are able to provide these devices to smallholder farmers. It is jointly implemented by ACDI/VOCA and its affiliate Agribusiness Systems International under the direction of Meridian Institute. For more information on AflaSTOP and other key reports and resources, visit: Agribusiness Systems International (ASI) contracted Catapult Design to research, design and field test a new maize drying technology adapted to the needs of Kenyan smallholder farmers, permitting them to confidently, easily, and cost-effectively dry maize down to safe, long-term storage moisture content regardless of weather conditions. Alpha prototype performance testing identified the Portable Shallow-bed Batch Dryer (henceforth referred to as the dryer ) as having the highest potential for further development. Design recommendations from alpha prototype performance testing were incorporated into an improved beta prototype which was field tested with six (6) end-users (dryer operators) and eight (8) primary beneficiaries (smallholder farmers) over six (6) days during the March 2015 maize harvesting season in the Meru, Kenya area. A comparison between the alpha and the beta prototypes with the design recommendations from alpha prototype performance testing incorporated is highlighted in Appendix A. 2. Field Testing Objectives and Methodology 2.1. Testing Objectives In contrast to the alpha prototype s performance testing, the primary objective of the beta prototype field testing was to conduct user experience evaluation of the dryer as well as to assess its qualitative demand within the operator and farmer s cultural and environmental context. Secondary but important objectives of the field testing were: To evaluate the beta prototype s performance when operated by target operators under representative environmental conditions. To collected data relating to the ability of farmers to accurately judge correct moisture content of the maize for safe storage as this may influence their willingness to pay. To determine the dryer s operating cost as it is being utilized as the key piece of equipment in a mobile drying service. To investigate local, informal manufacturing capabilities to evaluate what fabrication capacity they offer, having a possible influence on commercialization Methodology Six (6) target operators (current agricultural service providers and equipment fabricators) from three (3) maize producing areas (Meru/Nanyuki, Nakuru and Eldoret) were selected and instructed to enact a hypothetical mobile maize drying service to eight (8) local maize farmers. The six (6) operators were divided into three (3) groups of two (2), paring local Meru with out of area operators to promote cultural sensitivity and communication. Each group was evaluated for two days, the first day focusing on user experience of the operator using the dryer with the second focusing on the desirability of a proposed mobile dryer service and farmer s willingness 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 1

8 to pay. Various evaluation criteria 1 and techniques were utilized to answer predetermined research questions relating to the above mentioned objectives through the following lenses: Usability: Quantifying the physical and/or cognitive interaction between operator and the dryer beta prototype to identify features or attributes that create obstacles to its operation. Acceptability: Quantifying the broader affective or aspirational values ascribed to the solution concept to identify features or attributes that create obstacles to its operation (and eventually, adoption), concentrating on the emotional interaction between the operator and the dryer beta prototype. Qualitative demand: Capturing as many as possible experiential factors that will hinder or promote eventual demand for the dryer by the farmers and their consistent, correct use by the operators Research Methods Observation The primary research method used was qualitative and observational and as non-interventional as possible with minimal facilitation or interaction with operators and farmers. When possible, remote observation with autonomous cameras or other recording devices were used. Contextual interviews and surveys Structured one-on-one interviews and surveys and were conducted during the execution of the hypothetical mobile maize drying service to assess the operator s business operation, farmer willingness to pay and manufacturing capacity within the local Kenyan context Schedule, Location and Environmental Conditions Field tests were conducted from March 2015 within a 5 km radius of Meru, Kenya. Ambient temperatures ranged from 21.3 ºC to 32.3 ºC with most days varying from sunny to partly cloudy. It is important to note that the proximity of the smallholder farms to a major nearby town most likely influenced testing results since farmers have been active within the Ministry of Agriculture s extension program and were located in areas accessible by most forms of transportation. What exactly this dynamic influenced and to what extent is currently unknown and speculative at best. 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 2

9 3. The Dryer s Operating Principle Com tion air Ambient drying air The dryer is transported to the location where the smallholder farmer stores their recently shelled maize, assembled within 30 minutes by erecting the modular shallow-bed and connecting it to the furnace/heat exchanger (HX) unit. Five (5) to six (6) bags (+/- 500 kg) of wet maize is loaded onto the shallow-bed and the furnace is ignited. Heated clean air needed for drying is generated through convection heat transfer by blowing ambient air over heated HX channels. The HX channels are heated by drawing hot furnace exhaust gasses through them and out the chimney. The hot exhaust gasses are constantly generated by Figure 1: Dryer operating principles steadily burning fuel (maize cobs) in the downdraft furnace. The heated air is blown into a canvas plenum with maize suspended on a perforated mesh bed above it. The air pressure builds up in the canvas plenum and forces heated air past the maize kernels with surface moisture wicked away. The maize is stirred at regular intervals to allow the moisture trapped in the lower layers closest to the heated air to escape. Once dry, the maize is offloaded via an offloading canvas chute for storage. The dryer can dry the 500 kg wet maize (+/- 20% moisture content) down a safe storage moisture content of 13.5% in +/- four (4) hours. 4. Dryer Configurations, Performance and Operating Cost Breakdown 4.1. Power and Shallow-bed Configurations Three (3) furnace/hx power and two (2) shallow-bed configurations were paired, tested and compared to evaluate usability, desirability, performance and operational costs of each combination. The furnace/hx main body remained the same throughout testing; only the power options and the fan driving mechanisms were interchanged and compared: Power Configuration 1 2 consisted of an off-the-shelf direct electric motor driven 18 exhaust fan (used in reverse to blow) and a belt driven off-the-shelf furnace 12 exhaust fan, both powered by a 2000 W petrol generator. A wheel and handles similar to a wheelbarrow was added to the furnace/hx unit as well on this configuration. Power Configuration 2 3 comprised of a v-belt driven custom fabricated 18 blower fan and an off-the-shelf 12 exhaust fan driven by a 1.5 HP electric motor powered by a 5000 W petrol generator. The blower fan had to be custom fabricated due to a reverse in rotation once the v-belt drive was introduced. 2 See Appendix B, Figure 4 3 See Appendix B, Figure 5 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 3

10 Power Configuration 3 4 consisted of a v-belt driven custom fabricated 18 blower fan and an off-the-shelf 12 exhaust fan driven by a 5.5 HP petrol engine. Shallow-Bed Configuration 1 5 comprised of a two (2) 4 x 4 shallow bed frames placed inside a canvas plenum with two (2) 4 x 4 perforated mesh panels placed on top of them. The canvas side walls were folded over a tight rope at the top of the stanchions and pinned between the perforated mesh panels and the bed frame. This resulted in a 4 x 8 shallow-bed assembly with a surface area of 32 sq. ft. Shallow-Bed Configuration 2 6 consisted of a four (4) 3 x 3 shallow-bed frame/panels hybrids placed inside the canvas plenum with individual removable feet suspending them above ground. The canvas sidewalls were suspended by a rope sewn into the canvas and clipped onto the top edges of the side stanchions. Retaining straps and clips were secured around the perimeter to avoid maize leaking into the plenum. This resulted in a 6 x 6 shallow-bed assembly with a surface area of 36 sq. ft. 4 x 8 Shallow-bed Chimney Canvas side walls Shade cloth Canvas Plenum Duct connection Heat exchanger (HX) 18 Blower fan 20 cm Maize bed 12 Furnace exhaust fan Downdraft furnace Figure 2: Power 1 and Shallow-bed 1 Configurations Chimney Duct connection 1.5 HP Electric motor 18 Blower fan V-belt and pulleys Furnace/HX unit Power supply Rainfly Retractable sides 18 cm Maize bed Canvas stanchions Retaining strap and clips Canvas plenum 4 See Appendix B, Figure 6 5 See Appendix B, Figure 7 6 See appendix B, Figure 8 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 4

11 Figure 3: Power 2 and Shallow-bed 2 Configurations 6 x 6 Shallow-bed Table 1: Power and Shallow-bed configuration test pairing Configuration Test 1 Test 2 Test 3 Test 4 Test 5 Power 1 x x Power 2 x x x Power 3 Shallow-bed 1 x x Shallow-bed 2 x x x 4.2. Performance Evaluation Performance test weather conditions Table 2: Weather conditions for each drying test Parameter Test 1 Test 2 Test 3 Test 4 Test 5 Start time 9:50 AM 9:10 AM 9:10 AM 12:50 PM 8:50 AM End time 2:51 PM 12:45 PM 12:00 PM 3:30 PM 11:20 AM Lowest ambient temperature ºC Highest ambient temperature ºC Weather conditions Sunny/ Sunny/ Partly cloudy Partly cloudy Sunny Sunny Sunny Performance test drying results Table 3: Drying performance test results for each drying test Performance Parameters 7 Test 1 8 Test 2 9 Test 3 10 Test 4 11 Test 5 12 No. bags of maize Initial MC: Final MC: Drop in MC: Operating time: 5:01 3:35 2:50 2:40 2:30 % MC drop/hour: Drying performance discussion Drying performance is greatly influenced by the temperature of the drying air that passes through the grain bed. When drying maize, it is recommended that the drying air temperature does not exceed 55 ºC for seed maize (restricted to avoid killing the germ) and 90 ºC for consumption (restricted to avoid cooking the maize kernel and cracking the outer most layer). Restricting the drying temperature (which can be done through optimizing the furnace/hx design) however reduces the efficiency of the drying process as colder drying air has a reduced capacity to absorb moisture from the maize as it passed through the maize bed. This means it will take longer and cost more to dry the same quantity of maize. 7 See Excel Worksheet Performance Data.xlsx 8 See Appendix C, Figure 14 9 See Appendix C, Figure See Appendix C, Figure See Appendix C, Figure See Appendix C, Figure 18 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 5

12 The test data collected highlighted that there was a large variation in drying performance, directly related to the large variation in drying air temperatures achieved. This variation was due to several influencing factors as mentioned below, some the operators had control over and others they did not: Ambient temperature Ambient relative humidity Moisture content of the maize Moisture content of the cobs Furnace fuel feed rate Thickness of the maize bed Processing intervals of the maize It is difficult to pinpoint exactly the extent of how each factor mentioned above influenced the drying air temperature since tests were conducted on various days by various operators. The following discussion therefore focuses on the major contributing factor and how it relates to the satisfactory and poor drying performances achieved by the operators. The greatest variation in drying air temperatures observed was attributed to the varying moisture content of the cobs used to fire the furnace, with the wetter cobs (shelled the morning of drying) burning at a lower temperature than dryer cobs (shelled a few days prior to drying). One solution to this unforeseen issue that was explored and proven effective during testing was to pre heat/dry the awaiting wet cobs with the radiant heat from the furnace. This solution is discussed in more detail below. Since it is so difficult to confidently predict and maintain a constant drying air temperature due to all the influencing factors, it is recommended to limit this dryer design to drying maize for consumption only and any seed maize should be dried using alternative methods. Care should also be taken to ensure that maize dried with this dryer design is not sold as seed maize in the market. All of the farmers that participated in this round of testing however commented that they sell all of their maize for consumption and prefer to buy hybrid seed maize to plant next season and it was therefore not a problem. It was also important to compare the custom fabricated fan performance to that the off-the-shelf fan to ensure that sufficient airflow was achieved against comparative static pressure imposed by the same maize bed depth. This was achieved by pairing both configurations with the same loaded shallow-bed and compare drying air volume passed through the fan using a handheld anemometer. A slight difference in capacity was observed with the custom built fan showing a slight disadvantage. On closer inspection it was noticed that the fan blades were leaning back with reference to the rotational plane. Rectifying this small misalignment should correct this issue, resulting in a custom fan design that can supply the required airflow at the imposed static pressure. Another observation was drying maize down at the lower moisture content levels also required more energy and time since the moisture had to migrate from the inner core of the kernel before it could be wicked away by the passing heated air. 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 6

13 4.3. Operating Cost Discussion Field testing revealed that the operating cost associated with offering a mobile drying service is mainly influenced by the factors below. Transportation of the dryer to the client. Labor costs associated with operating the dryer. Fuel cost associated with running the furnace/hx power source (generator vs. petrol engine). Fuel cost associated with firing the furnace (maize cobs). Equipment maintenance cost. It is important to note that some costs could not be determined during this round of testing due to testing conditions and should be explored in more detail during a pilot implementation. A discussion around what a mobile drying service associated costs may look like as informed by one-on-one interviews with the operators follows in place of hard numbers Transportation of the dryer to the client. A pickup truck was rented and supplied during this round of testing. This was done due to the fact that out-of-area agricultural service operators were included and did not have transportation options of their own. It was not possible to track fuel expenses since one vehicle was used to move various drying operations and it was almost impossible to distinguish which fuel expense to associate with what operation. A possible approach would be to estimate this operational cost by tracking distances traveled to each farmer and calculating fuel expenditures based on the vehicle s fuel economy. When asked about transportation, operators commented that clients were often served in sequence as they appeared on a service route and rarely did an operator make a special trip to serve only one client beyond clients at closer proximities. Some services were also offered concurrently (shelling and animal feed cutting/grinding), providing multiple income opportunities during the same transportation related expense. An estimation of 20% of the asking price for the service would often be allocated to cover these transportation expenses. They commented that ideal situation would be to move the dryer concurrently with other agricultural services already provided, possible leaving it behind with and operator and collecting it again once drying has concluded Labor costs associated with operating the dryer. No labor was hired during testing as the operators user experiences were being evaluated. A discussion around agricultural service labor revealed laborers are hired for the season, paid daily and that labor rates are mostly tied to productivity. Total labor rates are often estimated at around 10-15% of the related service fee depending on location and intensity of the physical excursion and/or the associated responsibilities. Labor rates in the Meru area were often quoted at twice that of labor rates in the North Rift area, however, Meru service fees were also double that of the North Rift area. Common manual labor rates for the Meru area often ranged between KES per day with operator rates varying from 1,500 2,500 KES per day. Even though the dryer can fully be assembled, operated and disassembled by one person, the norm in Kenya is to have two (2) people associated with any given service (one operator and one manual laborer) and this will most likely be the case with offering a mobile drying service. 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 7

14 Fuel cost associated with running the furnace/hx power source The selection of the ideal power solution for running the dryer as a mobile drying service is balance between affordability, performance to the required specifications, yet fuel efficient to minimize operating cost. Mainline electricity driving direct drive electric motors offers the lowest operating cost but is not available everywhere. A generator to supply power to the direct drive electric motors is an option but needs to be large enough to overcome the initial load requirements to start the motors (often three (3) times higher than the operating load). This results in generator selections that are often oversized with poorer fuel economy. An alternative to an electric motor and generator arrangement is using a small petrol engine. Once again, the initial load requirement requires an oversized petrol engine that has poorer fuel economy. It is possible to overcome the initial load requirement by providing a way to slowly introduce the load (such a clutch) but this increases the upfront investment needed to acquire the unit. When looking at analogous agricultural equipment, two clear approaches are followed to accommodate the various performance and geographical requirements mentioned above. Equipment is often sold having the same design offering either an electrical motor or a petrol engine driving a v-belt. The motors and petrol engines are often oversized to overcome the initial load requirements, nevertheless popular since these components are often interchangeable between equipment in the off-seasons with the associated upfront investment spread between multiple income streams. A similar approach was used and evaluated during testing with the following associated operating cost below: Power Configuration 1 relied on a 2000 W petrol generator to supply power to the two (2) electric motors (380 W blower and 75 W furnace exhaust). Power Configuration 2 relied on a 5000 W petrol generator to supply power to one (1) 1.5 HP electric motor driving both blower and exhaust fans with a v-belt assembly. Power Configuration 3 was configured post user-testing to evaluate the fuel economy of a commonly used but oversized 5.5 HP petrol engine. An estimation was then made to assess its associated operating cost as it relates to both Power Configuration 1 and 2 s drying performance. It was possible to take this approach since the dryer s power selection has no influence on drying performance, only operating cost. Since the fan torque requirements are low the larger petrol engine can operate at idle, burning less fuel than both smaller sized generators operating at normal load. Table 4: Power source fuel operating cost during testing (for the Kenyan audience) Power configuration Field testing Power Configuration 1 (2000 W generator) Power Configuration 2 (5000 W generator) Estimation Total runtime (hours) Fuel consumption (ml/hour) Total % MC drop Total Fuel 104 KES/liter Avg. cost (KES)/%MC drop Avg. cost (KES)/90 kg bag 6: : , Power 6: Configuration 3 10: See Excel worksheet User Experience Evaluation Assessment.xlsx 8

15 Fuel cost associated with firing the furnace (maize cobs) Initially it was thought that the cobs needed to feed the furnace would always influence the operating cost and had to be included in the calculations. This was however proven to be an incorrect assumption as during user testing farmers argued that money made by selling the cobs to the operators ( KES/bag) would just be paid back to the operator in higher drying charges. All the farmers involved during testing had sufficient amounts of cobs and were willing to offer them free of charge, not expressing any concern over the amounts that were consumed during the drying operation (+/- 10 kg/hour). Cobs do however have a value, are generally controlled by women, and are traditionally used for animal feed and cooking fuel and could potentially influence the operating cost where alternative feed or cooking fuels are not available Equipment maintenance cost. Equipment maintenance during agricultural services is greatly dependent on the equipment being used, operator care, and the maintenance associated with the selected transportation to offer the service. Conversations with operators concluded that around 20% of a service fee is often allocated to cover maintenance costs. Maintenance is often performed by the owner of the equipment themselves. When this is not possible, the equipment is returned to where it was originally fabricated or bought for repairs. Field testing was conducted over too short of a period to have a clear understanding of what maintenance schedule will be involved for the dryer and a longer pilot is recommended. An assessment could however be made by inspecting Power Configuration 1 (direct driven fans with 2000 W generator) and Shallow-bed Configuration 1 (2 x 4 x 4 fixed beds) since this unit combination was being used by a 3 rd party organization and had been running it continuously for six (6) weeks. The furnace and HX was visibly worn and would potentially require maintenance first if the material choices associated with the designs remained the same. Bearings also required frequent re greasing (approximately every 3-5 days). The coffee mesh on the shallowbed had frayed in some sections due to processing and required repairs. There were also holes in the canvass, mostly at the top where it had been pulled during set up, with some small holes below the maize bed level. These will deteriorate over time, requiring patching and finally replacement of the canvass. The exact cost associated with the maintenance as mentioned above is currently unknown and will require a longer testing period to establish. 5. User-Experience Assessment 5.1. Testing participant profiles End-user (operator) profiles Six (6) target operators (current agricultural service providers and equipment fabricators) from three (3) maize producing areas (Meru/Nanyuki, Nakuru and Eldoret) were selected. Most operators had both primary and secondary income streams that were seasonal, with secondary income streams often utilized to finance future equipment purchases. The Nakuru and Eldoret operators relied predominantly on farming as a secondary income, farming acres of maize or wheat (10 40 acres of which they own) with Meru/Nanyuki operators finding 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 9

16 secondary income in fabrication and taxi services. They all owned their own equipment or were currently in the process of paying it off by saving income for an average of two (2) seasons, paying for equipment in full or placing a deposit for fabrication. Equipment owned varied between operator and included shellers, tractors, trailers (Nakuru/Eldoret) and shellers, motorcycles, puck-up trucks and cob grinders (Meru/Nanyuki). A detailed breakdown of the operator profiles can be found in Appendix D Primary beneficiary (Farmers) profiles Eight (8) farmers participated in testing and consisted of two (2) major groups, farmers who rely on the maize harvest as either their primary source of income or own consumption and those who rely on the maize as their secondary source of income. Harvests ranged from four (4) to fifty (50) bags with homesteads varying from modest to modern. Some larger farmers had motorized transport with others investing in farm animals such as dairy cows, pigs, goats and chickens. A detailed breakdown of the farmer profiles can be found in Appendix D User-experience assessment (Device) Both the end-user (operator) and primary beneficiary s (farmer) experienced were considered as perceived through a proposed mobile maize drying service. The discussion below highlights chronological touch points and the accompanying experiences associated with each action Transportability The user experience around transportability was evaluated as it relates to the operator s transportation preference and client s (farmer) location. Since testing was performed in and around the town of Meru using a provided pickup truck, oneon-one interviews were conducted to gather information on how operators currently perform agricultural service offerings and what they propose as possible transportation options for a mobile drying service. Observations were made on how the dryer units were arranged and secured for transportation. All of the operators commented unanimously that their preferred mode of transportation is greatly influenced by what they already own and use to operate other agricultural services since the up-front investment of adding equipment to move the dryer is cost prohibitive. These transportation options range from tractors with trailers to pickup trucks to donkey carts and motorcycles. Operators also mentioned that transportation preference varied depending on the distance traveled and road conditions to serve a client and that a more fuel efficient/road accessible option will be chosen if multiple forms of transportation are available. Larger transportation options will also allow them to move more than one piece of equipment at a time, sharing the transportation cost amongst multiple revenue streams. Shallow-bed Configuration 1 (2 x 4 x 4 fixed beds) proved to be more challenging to transport without damage than Shallow-bed Configuration 2 (4 x 3 x 3 modular beds). Care was taken in the mornings to nest the beds properly to avoid damage during transportation. This was however not the case in the afternoons once the drying cycles were completed. Operators were tired and therefore less cautious when packing the units for demobilization. The permanently fixed legs and canvas stanchions made it cumbersome to stack safely which resulted in damage to the coffee mesh during transportation. Shallow-bed Configuration 2 s multiple components 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 10

17 made it difficult for the operators to keep track of, raising concerns of components going missing over time. Both Power Configurations 1 and 2 required additional space to transport their respective generators. In Power Configuration 3 the 5.5 HP engine can be secured on top of the furnace for transportation and does therefore not require additional space. The added wheel of Power Configuration 1 required additional space as well Design recommendations and possible next steps Shallow-bed Configuration 2 s smaller modular design and the Shallow-bed Configuration 1 s simplicity are both appealing; therefore combining these two attributes will yield the most promising design for transportability. Power Configuration 3 showed the most promise as far as the furnace/hx s transportability is concerned since no additional space is required to move a generator. The reality is that different locations will have different transport norms. The configuration as mentioned above can be easily transported in the Nakuru/Eldoret area where tractors and trailers are used, however the size and weight of the furnace/hx is unlikely to be loadable on a motorcycle if that is preferred in the Meru area. The appeal of a motorcycle s ability to access remote locations warrants further discussions around possibly mounting the dyer unit on wheels to be pulled by the motorcycle as a trailer. Care should be taken to ensure that sufficient suspension is designed into the unit to ensure it survives the rural roads. Exercising this option is currently not economical since the current design s drying capacity and service potential (1 MT in 8 hours) does not justify the additional cost. An auto rickshaw (or better known in Kenya as a tuktuk) may be the ideal intermediate solution, however they are only available in limited locations Deployment Drying location selection and offloading Farmers showed little to no concern on where the drying operations were to take place. Any concerns mentioned before operations around fire, noise and smoke were disregarded once the farmer saw and understood how the device operated. On one occasion the operator placed dirt under the furnace to prevent the grass in contact with it to catch fire. The transportability of the dryer made it possible for the drying operation to take place where the shelled maize was being stored. It was clear to the operators that a relatively flat area was required for the shallow-bed with most homesteads having sufficient open flat space. The weight of the furnace/hx unit required four (4) people to offload it. Farmers or bystanders stepped in to help the operator without instruction. The provided handles were used as predicted and the units were loaded and offloaded on multiple occasions without incident Set-up Setting up Shallow-bed Configuration 1 (2 x 4 x 4 fixed beds) was the most intuitive. The simplicity of placing the 4 x 4 bed frames into the canvas and placing the 4 x 4 perforated mesh panels on top of them made for a rapid assembly (under 10 min). The challenge came in securing the canvas between the bed frame and the perforated mesh panels as it was made too 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 11

18 small, resulting in maize leakage into the plenum and having to add shade cloth to prevent it. Uneven ground also posed a challenge since the design allowed for limited flex. Participants were often observed placing supports (rocks, timber, bricks, etc.) under the feet to stabilize the beds. This is problematic since the canvas (that needs to remain airtight) runs the risk of being punctured by the legs and the objects used to support it. Setting up Shallow-bed Configuration 2 (4 x 3 x 3 modular beds) was initially challenging for all of the operators. The spacial perception required to place the correct panels in the correct order and locations proved to be problematic. Any legs or panels that were placed in the incorrect location required the entire assembly to be dismantled and reassemble from the beginning, wasting time. An operation that should have taken 10 min ended up taking 30 min or more. The tight tolerances required to ensure a sturdy base between the 3 x 3 perforated mesh panels and their respective legs did not allow for unevenness of the underlying terrain. One plus was the manageable size and weight of the respective components. One person could erect the bed without any assistance. Another plus was the flexibility to absorb any irregularities in the terrain since the four (4) 3 x 3 beds could float individually of one another. The furnace/hx unit required little to set-up time. The chimney was placed and the shallow-bed connected with an elastic strap (long strip of tire inner tube commonly used in Kenya. This common mechanism for tying goods may need to be readdressed as a long-term solution since tubeless tires are entering into the market. With Power Configuration 3 the 5.5 HP petrol engine will have to be moved from its transportation location to the side of the furnace where it will connect to the v-belt assembly. When asked if a generator/electric motor or a petrol engine is more desirable, all of the operators responded that they prefer the petrol engine since it is interchangeable on other equipment they already own Design recommendations and possible next steps The simplicity of Shallow-bed Configuration 1 and the flexibility of Shallow-bed Configuration 2 are both appealing. The uneven ground highlighted the restriction on tight tolerances and relying on components that use tight interlocking fits. The recommendation is to combine the designs, resulting in a bed frame and panel design that is modular and flexible with fewer loose components that does not require tight tolerance fits Operation Loading maize onto the shallow-bed Kenyan maize storage sacks currently holds 90 kg of maize. This makes for an awkward and unwieldy two (2) person affair when moving maize regardless of the purpose. Different approaches were used by different operators to load the maize with the most common being the following: Collapsing a canvas sidewall and letting the maize sack rest against the bed with the bag then rolled onto the bed using the bed edge as support. It was then opened by a person standing on the bed, spreading the maize evenly with their hands and feet. Leaving the canvas sidewall intact and suspending the maize bag over the edge where it was opened and the maize distributed using hands. This method seemed more 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 12

19 cumbersome with the bags often resting on the stanchions, damaging the bags and leaving the farmer upset. A serious concern with both designs was the tendency of maize to leak into the plenum between the canvas sidewalls and the perforated mesh panels. With Shallow-bed Configuration 1 (2 x 4 x 4 fixed beds) the canvas sidewalls were not long enough to be successfully pinned between the panels and the frame. This concept shows promise but caution should be taken to ensure the correct sizing is achieved. Shallow-bed Configuration 2 (4 x 3 x 3 modular beds) was greatly problematic in this area. The fact that the bed resided within the canvas sidewalls did not allow for a tight connection and make-shift clips had to be added t o complete the week s te sting. The original ratchet strap concept to restrain the sides also proved to not only be unsuccessful but unintuitive to the operators as well Lighting the furnace Lighting a fire seemed to be very intuitive in this part of the world. No instructions were necessary and the furnace lit successfully at first attempts. Available maize stover was often used to start the fire with cobs added on top. One observation was the need for air supply at the bottom of the furnace to allow the furnace to generate a sufficient thermal mass of burning fuel before the exhaust fan is engaged and the fire is drawn downwards through the HX. Operators often had to use a fanning device or blow on the fire to supply sufficient oxygen for combustion, placing their faces in close proximity of the furnace and breathing in unwanted smoke. A concern that arose was the difficulty associated with lighting recently shelled maize cobs. The moisture content was often too high to ignite sufficiently and drier cobs were needed to start the fire. Once the furnace was lit the wetter cobs did burn but at a lower burn rate and produced lower temperatures and more smoke than dry cobs. The lower temperature output from the fire was problematic at this impacted the HX temperature and therefore the drying air temperature. Lower drying temperatures impacted the drying air s ability to absorb moisture and therefore led to longer drying times. As mentioned before, a low cost solution was designed and tested in the field. A removable basket was placed over the furnace wit awaiting cobs dried to an acceptable moisture content that resulted in the preferred furnace operating temperatures. Figure 4: Cob preheating/drying basket Feeding the furnace There was an initial tendency by all of the operators to overfeed the furnace. This resulted in a lack of oxygen, smothering the fire at times to a point where it had to be relit. Once this was observed, operators adjusted feed rate and achieved the desired burn rate without much oversight or instruction. The feeding intervals ranged from 5 to 10 min, allowing for one operator to run the system since the time in between stoking the furnace is sufficient to process the maize. The downdraft furnace design made this operation safe and easy to execute Processing the maize The concept behind processing the maize was easily understood as it closely resembles the stirring of maize when dried in traditional ways on a tarp in the sun. The operator were instructed to process the maize at 30 min intervals and kept to the schedule for the most part. 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 13

20 Some used the provided stirring utensil and made one from an old discarded oil container when one was not supplied. Other operators used their hands to process the maize and managed to do so effortlessly and successfully. When asked about this practice they all replied that they preferred to feel the maize temperature by hand and could tell where the hot bottom layer of maize where that needed to be turned. Stirring by hand required the operator to bend over the canvas sidewall into the maize bed footprint, exposing them to airborne chaff that could pose health concerns over the long term. The occasional frayed wires from the coffee mesh were also a concern when processing by hand as it caused minor injuries Offloading the maize Once dried, two different approaches were used to offload the maize into awaiting 90 kg sacks. One approach was to place the provided offloading chute into a sack and rake the maize into it either by hand or using the provided processing utensil. Shallow-bed Configuration 1 had a smaller chute opening when compared to Shallow-bed Configuration 2 and proved to be more user friendly and desirable. The other approach used was to use a bucket to gather and scoop the maize into the sacks, paying no attention to the chute Design recommendations and possible next steps The recommendation is to redesign the shallow-bed so that it is a combination of Shallow-bed Configurations 1 and 2, resulting in a modular bedframe and panel design with the legs sitting outside of the canvas plenum, creating a tight maize seal with a small mouth offloading chute that can be directed to where the maize is needed. A sack loading support was also suggested to aid in supporting the maize sack above the canvas sidewall to prevent damage during loading. Adding air supply breathing holes at the base of the furnace will alleviate and need to fan or blow on the furnace fire as it is being lit. Having dry cobs on hand to start the furnace is also advised. A removable mesh tray that can fit above the furnace is recommended to dry and/or preheat and wet cobs to ensure higher burning temperatures. Using gloves and a face mask is recommended if the maize is processed by hand Teardown and demobilization Disassembling either of the shallow-bed configurations was achieved within the desired 10 min timeframe with minimal instruction or effort. In the case of Shallow-bed Configuration 1 (2 x 4 x 4 fixed beds), any irregularities in the terrain caused the connections to freeze up under weight, making it cumbersome to disassemble. The greatest concern however was around the heat retention of the furnace and how the insulation (required as a safety precaution to prevent contact burns) prevented the furnace from cooling down in a timeframe that made it feasible for the unit to be moved between multiple clients in a given day. The furnace remained too hot to handle for up an hour after operation seized. Water was occasionally used to cool the furnace down, an undesirable practice since quenching heated metal causes brittleness and so decreasing the expected lifespan of the unit. This was clear as the back end of the furnace deteriorated to the point of needing repair within one week s testing. 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 14

21 Loading the dryer after a long day s work also highlighted the need for the design to be robust enough as the components were often thrown onto the back of the pickup or onto the ground with little caution taken to prevent damage Design recommendations and possible next steps Once again, combining the attributes of Shallow-bed Configurations 1 and 2 will result in a simple, transportable design that is easy to assemble and disassemble yet robust enough to withstand constant use and abuse. Making the furnace removable may assist in quicker demobilization. An alternative to insulation is to use protective mesh as a safety precaution, allowing the furnace to cool down at a much faster rate, eliminating the need to cool it down by quenching it with water. 6. Qualitative Demand and Willingness to Pay Assessment 6.1. End-users (Operators) All of the participating operators showed overwhelming interest in understanding how the dryer worked and commented that they were interested in owning and operating a mobile drying service. When asked what they were willing to pay, the majority preferred to have the unit to pay for itself within one (1) to two (2) years rather than committing to a set purchasing price. Structured financing for agricultural equipment is uncommon in Kenya and most of the operators either saved up for approximately two (2) years (farming or doing other work) or paid a lump sum in full for the large equipment they currently own. This often means that large equipment (tractors and some tractor mounted shellers) is bought second hand (used) from friends, family or neighboring farmers with smaller, more affordable equipment often bought new and paid for cash on receipt. When paying in full is not possible, an arrangement is made with the equipment fabricator to start fabrication on a 50% deposit with the balance paid monthly during the operating seasons. A purchasing agreement is signed by the fabricator, new owner and witnesses with the equipment paid for in full within two (2) seasons or one (1) year with no interest charged. When probed on how operators would offer a mobile drying service, two (2) out of the three (3) North Rift operators (operators from Nakuru and Eldoret) raised concerns about the drying capacity of the current design. They currently service forty (40) to fifty (50) bag maize framers, implying that the dryer would have to remain with one farmer for four (4) to five (5) days working through maize that only took one (1) day to shell. This complicates things and limits their options to offer the drying and shelling services simultaneously since their shellers can easily shell fifty (50) bags in eight (8) hours with the dryer only drying ten (10). High moisture shelled maize (18% and above) runs the risk of spoiling if not dried in time and waiting four (4) to five (5) days to dry all of the farmer s maize may be problematic. One solution to this dilemma would be to shell only a manageable twenty (20) bags at a time, service other clients and returning to shell the next twenty (20) bags as the dryer near its final drying cycle. Another solution, as suggested by one of the North Rift operators, will be to eventually buy more than one machine to handle larger farmer needs. They also understood the constraint that a larger capacity machine would cost significantly more. Operators did not raise any concerns about trusting possible dryer service employees since this is often the current agricultural service offering practice as well. Meru agricultural service 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 15

22 providers did not share the same concerns about dryer capacity as their client farmer harvest (5-10 bags) falls well within the dryer s drying capabilities. When asked what the operators would charge per bag to offer a drying service all of them commented that it depends on demand and the price maize is currently fetching at market. The higher the demand for services (in the event of inclement weather) and the higher dry maize price is trading (or the more farmers are penalized for supplying wet maize), the higher the drying rates will be. This is a similar model witnessed within the sheller service providing. When pushed for answers, prices ranged from KES per bag Primary Beneficiaries (Farmers) Farmers were asked to comment on their willingness to pay for a drying service before drying commenced and after drying completed with conflicting responses. Almost all farmers were hesitant to commit to a fixed number when asked beforehand and pricing ranged from 50 to 100 KES to dry each bag. However, most farmers were willing to pay close to double their original amount once they witnessed the drying operation and the resulting dried maize. Another interesting observation was that farmers who shelled their own maize by hand were often reluctant to pay anything for a drying service since they have no reference to expenditures around maize post-harvest processing and their maize quantities were often manageable in case of inclement weather. Farmers perception on maize dryness was also compared to accurate moisture readings and found to be inconstant and inaccurate. Farmers perception of moisture content as a number was arbitrary as well since they had no real reference point - a more relevant question to them was how many more days does it need to sit in the sun before it is dry. When compared to calibrated moisture readings, most farmers indicated a safe storage moisture content of around 15%, corresponding to known maize storage trends. It is assumed that this moisture content preference will impact the drying service business model since farmers will not be willing to pay for any drying beyond where they believe it is necessary for safe storage. This factor will most likely impact the time spent at one client since drying maize down gets exponentially more time consuming when a lower moisture content is desired. It is therefore possible that the dryer could potentially dry upwards of bags per day if it only needs to dry maize down to 15%. Below follows a table of the farmers moisture content assessment: Table 5: Farmers moisture content assessment Performance Parameters Farmer 1 Farmer 2 Farmer 3 Farmer 4 Farmer 5 Initial MC: Farmer s MC assessment at the point where they perceived the maize to be dry enough to store: Actual MC at assessment at the point where farmers perceived the maize to be dry enough to store: Final MC: One farmer had varying moisture content maize due to harvesting and shelling schedules. This made for a complicated drying operation as some maize required more drying time than others. Maize was ultimately mixed as moisture equilibrium will be reached during storage if maize with varying moisture content is still prevalent after drying. It is unclear how this reality will affect the maize drying business model and possible drying methodologies should be explored during a 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 16

23 longer pilot. Farmers were also not willing to mix their maize for the same reason amongst others. 7. Conclusion The Portable Shallow-bed Batch Dryer was intuitive and simple to operate. It uses a similar principal as traditional drying methods and was easily understood and accepted. All of the operators commented that the design was simple yet elegant with the farmers being please with the end result. The best shallow-bed configuration is one that has few parts, comprises of a bed frame and panels, yet being transportable by having a system that can collapse into a manageable footprint. The furnace/hx unit with a petrol engine, v-belt drive and a removable heat source is the most promising and desired configuration. Both operators and farmers showed interest in what the dryer has to offer and commented that the service is in dire need with them willing to pay for the service. 1 See Excel worksheet User Experience Evaluation Assessment.xlsx 17

24 Appendix A Alpha Prototype vs. Beta Prototype Comparison PORTABLE SHALLOW-BED BATCH MAIZE DRYER ALPHA PROTOTYPE PORTABLE SHALLOW-BED BATCH MAIZE DRYER BETA PROTOTYPE Rain cover Chimney Primary fan Heat exchanger (HX) Updraft furnace Combustion supply air 6 x 6 Shallow-bed Rain cover Chimney Updraft furnace Combustion supply air Heat exchanger (HX) Primary fan 6 x 6 Shallow-bed Rain cover - 5 m x 6 m Blue tarp with separate square tube supports Chimney mm Galvanized sheet metal Primary fan -18 off-the-shelf electric motor direct driven Heat exchanger (HX) - 20 x 20 x 0.5 mm galvanized sheet metal Updraft furnace - 1 mm Mild steel sheet with hopper and hopper door Combustion supply air - 12 off-the-shelf electric motor direct driven 6 x 6 Shallow-bed - Fixed 6 x 6 frame with fixed 6 x 6 bed panel Rain cover - 2 m x 2 m PVC canvas with integrated square tube supports Chimney - 1 mm Mild sheet metal for durability Primary fan -18 custom fabricated v - belt driven Heat exchanger (HX) - 10 x 20 x 1 mm Mild sheet metal Downdraft furnace - 1 mm Mild steel sheet with cob preheating basket Combustion supply air - 12 off-the-shelf v - belt driven 6 x 6 Shallow-bed Modular 3 x 3 frame/bed hybrids Cost estimate of the prototype (material and fabrication): Cost estimate of the production (material and fabrication): 226,000 KES 90,500 KES Cost estimate of the P1 and S1 prototype (material and fabrication): 158,600 KES Cost estimate of the production (material and fabrication): 142,800 KES Cost estimate of the P2 and S2 prototype (material and fabrication): 120,700 KES Cost estimate of the production (material and fabrication): 104,900 KES 18

25 PORTABLE SHALLOW-BED BATCH MAIZE DRYER ALPHA PROTOTYPE PORTABLE SHALLOW-BED BATCH MAIZE DRYER BETA PROTOTYPE Furnace/HX Assembly Deficiencies Design Recommendations Furnace/HX Assembly Improvements Leaking HX. Temperature hypersensitivity Heat radiation of primary fan. Safety due to radiation for furnace. Duct connection damaged due to furnace radiation. Clogged grate during operation Exhaust combustion air to avoid contamination. Increase HX metal thickness. Move primary fan adjacent to furnace vs. above. Insulate the furnace. Move duct connection adjacent to furnace vs. aside. Increase grate spacing and regulate furnace temperatures. Exhaust combustion air with negative pressure to avoid contamination of grain by smoke leakage. HX redesign to be less sensitive to furnace temperature variation and better temperature distribution throughout. Primary fan placed adjacent to furnace. 5.5 HP engine vs. electric motor and generator to avoid environmental concerns due to moisture. Insulated furnace to reduce burn risk and increase efficiency. Duct connection placed adjacent furnace to protect it from radiant heat. Grate spacing was increased and appropriately sized. Shallow-Bed Deficiencies Design Recommendations Shallow-Bed Improvements Maize leaked into the plenum. Safety concern due to coffee mesh fastening Labor requirement to assemble the bed. Longevity concern of the canvas plenum during assembly. Transportability Cumbersome offloading. No rain protection Restrict maize by supporting the plenum perimeter. Use continuous fastener to secure coffee mesh. Redesign footprint so that one operator can assemble the bed. Increase plenum size to allow for a bigger tolerance between legs and canvas. Reconfigure design to be more transportable. Include offloading chute. Include rain fly in case of rain. Perimeter ratchet strap/rope is included to restrict maize from leaking into the plenum. Perimeter continuous frame to secure coffee mesh to each 3 x 3 bed is included. One 6 x 6 bed is reconfigured to four more maneuverable 3 x 3 beds with removable supports. Canvas plenum size increase to allow for easier assembly and less abrasion between legs and canvas. One 6 x 6 bed is reconfigured to four more maneuverable 3 x 3 beds with removable supports. Offloading chute is included in canvas redesign. Rain fly is included in design. 19

26 Appendix B Power and Shallow-bed Configurations and Material Breakdown 1. Power Configuration 1 Power Configuration 1 consisting of an off-the-shelf direct electric motor driven 18 extraction fan (used in reverse to blow) and a belt driven off-the-shelf 12 furnace exhaust fan, both powered by a 2000 W petrol generator. A wheel and handles similar to a wheelbarrow is added to the furnace/hx unit as well on this configuration. Chimney connection Downdraft furnace Furnace exhaust fan Direct drive blower fan with 380 W electric motor Figure 5: Power Configuration 1 of the dryer beta prototype Table 6: Dryer beta prototype Power Configuration 1 material breakdown Power Configuration 1 Material Quantity Material Unit Price (KES) Total Material Cost (KES) Main Furnace/HX body 1 mm Mild steel 4 x 8 sheet (Black plate) mm Mild steel 4 x 8 sheet (Black plate) " Rockwool Insulation (roll) x 20 mm Mild steel 6 m flat bar Wheel barrow wheel mm x 25 mm Mild steel 6 m angle iron Mild steel expanded metal mesh (4 x 8 ) Heat Exchanger 1 mm Mild steel 4 x 8 sheet (Black plate) " Off-the-shelf exhaust fan (Orient Electric 450 mm Heavy Duty Exhaust Fan) " Off-the-shelf exhaust fan (Orient Electric 300 mm Heavy Duty Exhaust Fan) WASP WSP W petrol generator " Fan drive mechanism Flat belt Pulleys ((2) x 2" Flat) /2'" Mild steel shafts Bearings (2 x 1/2" roller) Total Material Cost KES 62,

27 2. Power Configuration 2 Power Configuration 2 consisting of a v-belt driven custom fabricated 18 blower fan and an offthe-shelf 12 exhaust fan driven by a 1.5 HP electric motor powered by a 5000 W petrol generator. The blower fan is custom fabricated due to a reverse in rotation once the v-belt drive is applied W Generator Chimney 1.5 HP Electric motor Heat exchanger (HX) Downdraft furnace 12 Furnace exhaust fan V-belt and pulleys 18 Drying air supply fan Figure 6: Power Configuration 2 of the dryer beta prototype Table 7: Dryer beta prototype Power Configuration 2 material breakdown Power Configuration 2 Material Quantity Material Unit Price (KES) Total Material Cost (KES) Main Furnace/HX body 1 mm Mild steel 4 x 8 sheet (Black plate) mm Mild steel 4 x 8 sheet (Black plate) " Rockwool Insulation (roll) x 20 mm Mild steel 6 m flat bar Mild steel expanded metal mesh (4 x 8 ) Heat Exchanger 1 mm Mild steel 4 x 8 sheet (Black plate) " Custom blower fan 2 mm Mild steel 4 x 8 sheet (Black plate) " Mild steel custom fan hub " Off-the-shelf exhaust fan (Orient Electric 300 mm Heavy Duty Exhaust fan) HP electric motor W Generator capable of powering the 1.5 HP electric motor Drive mechanism Type A v-belt Pulleys with 10 mm pilot holes (2 x Type A, 1 x Type B) /4" Mild steel shafts Bearings (2 x F204, 2 x P204) Total Material Cost KES 143,

28 3. Power Configuration 3 Power Configuration 3 consisting of a v-belt driven custom fabricated 18 blower fan and an offthe-shelf 12 exhaust fan driven by a 5.5 HP petrol engine. Downdraft furnace Chimney Heat exchanger/hx 18 Drying air supply fan V-belt and pulleys 12 Furnace exhaust fan 5.5 HP petrol engine Figure 7: Power Configuration 3 of the dryer beta prototype Table 8: Dryer beta prototype Power Configuration 3 material breakdown Material Power Configuration 3 Quantity Material Unit Price (KES) Total Material Cost (KES) Main Furnace/HX body 1 mm Mild steel 4 x 8 sheet (Black plate) mm Mild steel 4 x 8 sheet (Black plate) " Rockwool Insulation (roll) x 20 mm Mild steel 6 m flat bar Mild steel expanded metal mesh (4 x 8 ) Heat Exchanger 1 mm Mild steel 4 x 8 sheet (Black plate) " Custom blower fan 2 mm Mild steel 4 x 8 sheet (Black plate) " Mild steel custom fan hub " Custom exhaust fan 2 mm Mild steel 4 x 8 sheet (Black plate) " Mild steel custom fan hub HP WASP WSP160 4-STROKE 25' inclined, single cylinder, air cooled petrol engine Drive mechanism Type A v-belt Pulleys with 10 mm pilot holes (2 x Type A, 1 x Type B) /4" Mild steel shafts Bearings (2 x F204, 2 x P204) Total Material Cost KES 41,

29 4. Shallow-bed Configuration 1 Shallow-Bed Configuration 1 consisting of a two (2) 4 x 4 shallow bed frames placed inside a canvas plenum with two (2) 4 x 4 perforated mesh panels placed on top of it. The canvas side walls are folded over a tight rope at the top of the stanchions and pinned between the perforated mesh panels and the bed frame. This results in a 4 x 8 shallow-bed assembly with a surface area of 32 sq ft. Canvas side walls Offloading chute Retaining rope Connecting duct 4 x 4 Panels 4 x 8 Shallow-bed 4 X 4 Bed frame Canvas plenum Figure 8: Shallow-bed Configuration 1 of the dryer beta prototype Table 9: Dryer beta prototype Shallow-bed Configuration 1 material breakdown Shallow-bed Configuration 1 Material Quantity Material Unit Price (KES) Total Material Cost (KES) 4' x 8' Shallow-bed (2) x 4' x 4' Bed frame and panel sections 40 x 40 x 3 mm Mild steel 6 m angle iron x 25 x 1.2 mm Mild steel 6 m square tubing /4" Galvanized steel coffee mesh (2 x 3 x 8 ) " Mild steel wire mesh (4 x 8 ) x 20 mm Mild steel 6 m flat bar PVC Canvas Plenum Shade Cloth PVC Canvas Rainfly Total Material Cost KES 15, Shallow-bed Configuration 2 Shallow-Bed Configuration 2 consisting of a four (4) 3 x 3 shallow-bed frame/panels hybrids placed inside the canvas plenum with individual removable feet suspending them above ground. The canvas sidewalls are suspended by a rope sewn into the canvas and clipped onto the top edges of the side stanchions. Retaining straps and clips are secured around the perimeter to avoid maize leaking into the plenum. 23

30 Canvas side walls Retaining rope Offloading chute Rainfly stanchion 6 x 6 Shallow-bed Connecting duct 3 X 3 Panels Removable feet Canvas plenum Figure 9: Shallow-bed Configuration 2 of the dryer beta prototype Table 10: Dryer beta prototype Shallow-bed Configuration 2 material breakdown Shallow-bed Configuration 2 Material Quantity Material Unit Price (KES) Total Material Cost (KES) 6' x 6' Shallow-bed (4) x 3' x 3' Bed frame sections 40 x 40 x 3 mm Mild steel 6 m angle iron x 25 x 1.2 mm Mild steel 6 m square tubing /4" Galvanized steel coffee mesh (2 x 3 x 6 ) x 20 mm Mild steel 6 m flat bar " Mild steel wire mesh (4 x 8 ) PVC Canvas Plenum PVC Canvas Rainfly Total Material Cost KES 15, Prototyping cost vs. Production Cost The table bellows highlights the cost comparison of prototyping cost vs. production cost as outlined by one representative local fabricator Kenya Stove. Table 11: Prototyping vs. production cost comparison Prototyping Production Power 1 and Shallow-bed 1 Configuration Power 3 and Shallow-bed 2 Configuration Power 1 and Shallow-bed 1 Configuration Power 3 and Shallow-bed 1 Configuration Material Costs 62, , , , Workshop Overhead 10, , , , Machining Time - 5, , Labor 18, , , , Profit 45, , , , VAT 21, , , , Total Cost (KES) 158, , , ,

31 Appendix C Performance Test Graphs 1. Ambient Air vs. Drying Air vs. Maize Temperature (ºC) The following graphs Illustrates how drying the air temperature increases the grain temperature from ambient temperature over time and how it differed between power and shallow-bed configurations. This increase in grain temperature ultimately expelled moisture from the inside of the kernel and was wicked away by the passing air. Ambient Air vs. Drying Air vs. Maize Temperature (ºC) Temperature (ºC) Temperature (ºC) :00 1:12 2:24 3:36 4:48 6:00 7:12 Time (Hour) Drying air temperature average (ºC) Maize Temperature avarage (ºC) Ambient Temperature (ºC) Figure 10: Test 1 - Ambient Air vs. Drying Air vs. Maize Temperature (ºC) P 2, S 2 Ambient Air vs. Drying Air vs. Maize Temperature (ºC) :00 0:28 0:57 1:26 1:55 2:24 2:52 3:21 3:50 Time (Hour) Drying air temperature average (ºC) Maize Temperature avarage (ºC) Ambient Temperature (ºC) Figure 11: Test 2 - Ambient Air vs. Drying Air vs. Maize Temperature (ºC) P 1, S 1 25

32 2. Variation in Grain Temperature (ºC) vs. Moisture Content (%) The following graphs illustrates that the theory of the variation in grain temperature (when compared between the hot drying air inlet and furthest point away from the heat source) will near zero as the moisture contents drops, is inconclusive since one test showed this to be the case and the other not. Test 1 s graph also shows that the moisture reading while the grain is hot from drying varies from the moisture reading of the grain when it has had time to cool. Variation in Grain Temperature (ºC) vs. Moisture content (%) Temperature (ºC) and Moisture Content (%) :00-5 1:12 2:24 3:36 4:48 6:00 7:12-10 Time (Hour) Maize Temperature difference (ºC) Moisture Content meter reading - Hot (%) Moisture Content meter reading - Cold (%) Figure 12: Test 1 - Variation in Grain Temperature (ºC) vs. Moisture content (%) P 2, S 2 Variation in Grain Temperature (ºC) vs. Moisture content (%) Temperature (ºC) and Moisture Content (%) :00 0:28 0:57 1:26 1:55 2:24 2:52 3:21 3:50 Time (Hour) Maize Temperature difference (ºC) Moisture Content meter reading - Cold (%) Figure 13: Test 2 - Variation in Grain Temperature (ºC) vs. Moisture content (%) P 1, S 1 26

33 3. Moisture Content (%) reduction over Time (Hours The following graphs Illustrates the drying performance of each power and shallow-bed configuration over multiple days. It is important to note that the moisture meter read different reading of the same maize sample when the grain was hot compared to cold. The farmers perception of maize moisture content is also shown to be inaccurate when compared to calibrated reading from a machine, however, consistent regardless of grain temperature (Test 1). Where the graph ends with relation to the farmer s moisture content perception illustrates where farmers were happy to store. Moisture Content (%) reduction over Time (Hours) Moisture Content (%) Moisture Content (%) :00 1:12 2:24 3:36 4:48 6:00 7:12 Time (Hours) Moisture Content meter reading - Hot (%) Moisture Content meter reading - Cold (%) MC farmer's reading of dryness - Hot (%) MC farmer's reading of dryness - Cold (%) Figure 14: Test 1 - Moisture Content (%) reduction over Time (Hours) P 2, S Moisture Content (% ) reduction over Time (Hours) 13 0:00 0:28 0:57 1:26 1:55 2:24 2:52 3:21 3:50 Time (Hours) Moisture Content meter reading - Cold (%) MC farmer's reading of dryness - Cold (%) Figure 15: Test 2 - Moisture Content (%) reduction over Time (Hours) P 1, S 1 27

34 Moisture Content (% ) reduction over Time (Hours) Moisture Content (%) Moisture Content (%) :00 0:28 0:57 1:26 1:55 2:24 2:52 3:21 Time (Hours) Moisture Content meter reading - Cold (%) MC farmer's reading of dryness - Cold (%) Figure 16: Test 3 - Moisture Content (%) reduction over Time (Hours) - P 2, S Moisture Content (% ) reduction over Time (Hours) :00 0:28 0:57 1:26 1:55 2:24 2:52 Time (Hours) Moisture Content meter reading - Cold (%) MC farmer's reading of dryness - Cold (%) Figure 17: Test 4 - Moisture Content (%) reduction over Time (Hours) P 1, S 1 28

35 Moisture Content (% ) reduction over Time (Hours) Moisture Content (%) :00 0:28 0:57 1:26 1:55 2:24 2:52 Time (Hours) Moisture Content meter reading - Cold (%) MC farmer's reading of dryness - Cold (%) Figure 18: Test 5 - Moisture Content (%) reduction over Time (Hours) P 2, S 2 29

36 Appendix D Testing Participant Profiles 1. End-user (Operator) profiles Table 12: End-user (Operator) profile breakdown Richard Nyambane Eric Mnangi Lawrence Mnangi Benjamin Kipkoech Simon Kithinji Noah Cheryot Jackson Thirikwa Age Highest Diploma in Diploma in Diploma in level of Diploma Class 8 Diploma Form 3 fabrication fabrication fabrication education Primary income activity Owner/ operator Years in business Service area Client radius Major Assets Price paid for asset Paid in full or installments Years to save up payment Activity to save Service season Agricultural service provider (Sheller) Owner Agricultural service provider (Sheller) Owner/ operator Agricultural equipment fabricator Employee Agricultural service provider (Sheller) Owner Agricultural service provider (Sheller) Owner/ operator Agricultural service provider (Sheller) Owner/ operator North Rift - Nakuru Nanyuki/ Meru Nanyuki/ Meru North Rift - Eldorete Meru North Rift - Eldorete 11 km 20 km NA 30 km 5 km 2 km NA Tractor with trailer, Sheller New tractor mil KES, New Sheller - 70,000 KES Paid cash in full Motorcycle, Sheller New motorbike - 150,000 KES, New Sheller - 100,000 KES Sheller - 40% deposit and 5,000 KES per month during the operating season. 2 seasons to pay in full NA NA NA 3 3 NA 2 Sold wheat Nov to March Motorcycle taxi Feb to March NA NA 2 Tractors, 2 Shellers Built the shellers himself (60 to 70K KES in material). 250,000 KES for the fabrication equipment Paid cash in full Designed and fabricated equipment, sold maize. Oct to Jan Pickup truck, Sheller, cob grinder 55,000 KES for Sheller Paid cash in full Paid in full from savings Military pension Feb to March 2 Tractors, 2 Shellers Used tractor - 300,000 KES, New Sheller - 100,000 KES Paid cash in full Agricultural equipment and building hardware fabricator Owner/ operator Meru Welder, grinder, drill, battery charger NA 2 NA Sold maize Oct to Jan Paid cash in full Designed and fabricated equipment NA 30

37 Service charge Ave. bags/day Ave. bags/farmer Fuel to shell 100 bags Labor rates Maintenance Secondary income activity Major assets Richard Nyambane 50 to 60 KES/bag to shell maize 50 to 100 Eric Mnangi 150 KES/bag* 50 wet, 70 dry Lawrence Mnangi NA Benjamin Kipkoech 50 KES/bag to shell maize 40 to 50 5 to 10 NA 100 to l - diesel Driver - 10% of day's earnings Self Maize and wheat farmer, cereal sales since acers of land 10 l dry, 15 l wet - petrol Assistant - 13 to 17 % of day's earnings Fabricator/ point of sale Motorcycle Taxi Motorcycle Simon Kithinji 80 to 120 KES/bag Noah Cheryot 50 KES/bag to shell maize NA 200 to to 70 max 100 to 200 NA 5 to 10, 25 max Jackson Thirikwa NA 100 to 200 NA NA 10 l - diesel 8.5 l - petrol 10 l - diesel NA NA NA Agricultural service provider (Sheller) 50% ownership of a Sheller with brother Eric Mnangi Driver - 10 to 15% of day's earnings Self Agricultural equipment fabricator 250,000 KES of machinery Assistant - 30 % of day's earnings Self except for welding Greenhouse farmer Driver - 10% of day's earnings Fabricator/ point of sale Farmer, buys and sells cattle NA Self NA Greenhouse Land NA *Eric Mnangi service charge to the farmer was KES 100 per bag. He just bought the machine so does not really know the operating costs. Table 13: Primary beneficiary (Farmer) profile breakdown Primary income activity Cash crop/own consumption No. of bags harvested this season Major Assets Farmer 1 School principle School consumption 6 Land, greenhouse Farmer 2 Retired accountant, school teacher Cash crop 50 Farmer 3 Spring water bottler Cash crop/own consumption 11 Farmer 4 Smallholder Farmer Cash crop/own consumption 6 Farmer 5 Smallholder Farmer Cash crop/own consumption 6 Farmer 6 Smallholder Farmer Cash crop 10 Farmer 7 Smallholder Farmer Cash crop/own consumption 4 Farmer 8 Smallholder Farmer Cash crop/own consumption 6 Land, vehicles, modern home Land, vehicles, modern home, bottling plant Land, modest home, farm animals Land, modern home, farm animals Land, modern home, farm animals Land, modest home, farm animals Land, modern home, farm animals 31

38 Appendix D Manufacturing Requirements and Capabilities As a starting point to better understand where the dryer could possibly be manufactured, analogous agricultural equipment (shellers, posho mills, cob grinders, etc.) supply chains were analyzed to better understand how a new technology came to the Kenyan market and what happened beyond its initial introduction. It was soon clear that new technologies are often introduced from abroad (often India or China) where it was fabricated in a manufacturing assembly line, and then reverse engineered and copied by the local Jua Kali fabricators once it hits the Kenyan market. Operators would then either buy used imported equipment for their peers or buy new directly from the Jua Kali fabricators. With this in mind, a breakdown of the manufacturing processes and equipment used to fabricate the dryer beta prototype follows below with an assessment made on whether it is replicable by the Jua Kali fabricators in a similar manner as other agricultural equipment as mentioned above. Table 14: Dryer beta prototype Shallow-bed fabrication requirements and Jua Kali capacity Shaping of Component Material Cutting of material material Furnace/HX unit Outer body and chimney Inner dividing walls HX channels Custom fans 1 mm Mild steel plate 2 mm Mild steel plate 1 mm Mild steel plate 2 mm Mild steel plate, 2 shaft Plasma cutter*/ Angle grinder/metal guillotine shear**,metal snips, Hand drill Plasma cutter/angle grinder Metal guillotine shear, Metal snips Plasma cutter/angle grinder, Hacksaw, Drill press/lathe Angle grinder, Metal break*** Joining of material MIG****/Arc welder, Pop rivet machine Jua Kali capability YES Metal break MIG/Arc welder, YES Metal break N/A YES, however attention to tolerances is important Angle grinder, Sheet metal roller MIG/Arc welder Shafts and bearings ¾ shaft Hacksaw Angle grinder Wrench set YES /Metal file Pulleys 2.5 and 3 pulleys with pilot holes Drill press/lathe N/A Wrench set YES Shallow-bed Canvas plenum PVC Canvas Scissors N/A Industrial sewing machine Shallow-bed frames and panels 1 Square tubing, 1 Angle iron, ½ Flat bar, 2.5 Wire mesh, Coffee mesh Hacksaw/Angle grinder, Metal snips, Hand drill Angle grinder MIG/Arc welder, Pop rivet machine YES YES YES *Plasma cutters are not common. Angle grinders are and can easily perform the same function. ** Metal guillotine shears are not common. Angle grinders are and can easily perform the same function. *** Metal breaks are not common. Railway tracks and hammers are and can easily perform the same function. ****MIG welders are not common. ARC welders are and can easily perform the same function. 32

39 Figure 19: Agricultural service equipment Figure 20: Agricultural service equipment fabrication 33