Product Development: DARK Cooler
Product Development | Prototyping | CAD | Market Research | 3D Printing
Among outdoors-people, there is no practical method for cooling perishable goods for long periods while backpacking or exploring nature.
As a result, hikers resort to highly processed and unappetizing alternatives like freeze dried meals:
DARK is a lightweight food storage solution which eliminates the need for heavy coolers and melting ice.
Project Description
In this project, my team of 4 was tasked with identifying a problem and target customer. The team then used a customer-centric design philosophy to develop a product to address this identified need.
Justification of the Problem
Our team identified outdoorsy-folk as a prime target product audience as these consumers are willing to pay a premium for improved functionality. I conducted customer research by interviewing potential customers on hiking trails and at stores like REI and Dick's about their top issues when outdoors, collecting 40 of the 63 interviews collected by the team. I also created a survey that was sent out the school population to collect data on customer signals.
44% of interviewees mentioned difficulties storing and cooling perishable food items as well as a general disliking of freeze-dried foods as an alternative to perishable goods.
Of our survey responses, 66.7% of respondents placed high importance on the transport of perishable goods. 88.9% of respondents found it difficult to transport coolers. 66.7% of respondents indicated interest in a portable iceless cooling device. 70.4% of respondents associated coolers with negative words such as "bulky" and "wet". 77.8% of respondents recalled bad experiences with coolers in relation to ice and weight.
From this customer research, the each analyze the data and created a hierarchy of customer needs was determined. I used this vision to drive the development of a product solution.
Competitive Market Research
I conducted market research of similar products to identify the weaknesses of our competitors and develop a plan for differentiating our product from others on the market.
Traditional Coolers: Coolers currently on the market can be divided into 2 categories: Cooling chests and cooling backpacks. The chests are typically passively cooled using ice and a thick plastic insulator shell. Backpack coolers use a proprietary light-weight insulating material blend to keep items cool. Conferring with customer reviews, an existing trade-off can be identified: While cooling chests have the cooling duration customers are looking for, they lack in portability. Meanwhile, cooling back packs have the needed portability while sacrificing cooling duration.
Active Coolers: Portable active coolers do exist yet they do not currently meet the portability needs of a backpacker. These coolers are either "mini-fridge" style or chest style. These coolers use thermoelectric cooling, where applying a power source to a semiconductor-based electronic component causes it to function as a small heat pump. This cools one face while heating the opposite face.
Thermoelectrics: The team consulted an expert to learn more about this technology. Cohen-Tanugi is the CEO of Embr, a start-up using a wrist mounted thermoelectric unit to help people regulate their body temperature. From a interview, we learned that these units can get from cold with only a couple watts of supplied energy as long as the heat is dissipated quickly enough for the hot side.
Market Size Research
I gathered data from reliable databases to make a case that there is a customer need for this product.
According to data from IBISWorld, the outdoor equipment sector is a $4.4 billion market with gear making up 30% of this sector making it a $1.32 billion market. The outdoor equipment sector has an annual growth of 1.6%.
According to Data from the 2017 American Camper Report: In 2016, 42% of all camping purchases were for coolers, with 53% of first time campers purchasing a cooler.
According to Data from Statistic, in 2017 $488.1 million was spent on coolers in the US, with the cooler market projected to reach $1.02 billion by 2025.
Product Requirements and Metrics
To translate the customer requirements to engineering requirements, I led team discussions to develop a House of Quality to identify which technical requirements should be prioritized in the design process based on how much they contribute to customer needs:
Based on the voice of our customer, the team identified the following product requirements:
- Effective Cooling: Cooler must reach temperature below 40 degrees Fahrenheit.
- Portability: Cooler must be under 3 pounds, and be no larger than 1 cubic foot
- Reliability: Cooler must be waterproof and withstand drops of up to 5 feet. The product must also have a battery-life of over 10 hours.
- Ice-free: Cooler must not rely on ice for cooling.
- Customizability: Internal temperature must be customizable to store both refrigerated and frozen foods.
To ensure the product performance, the following performance metrics will be collected to drive development:
- Internal Temperature remaining below 40 degrees Fahrenheit.
- Time internal temperature can be maintained given a full battery.
- Error between user input temperature and internal temperature.
- Customer satisfaction based on a survey after product testing.
Brainstorming a Solution
To begin developing a solution, each team member generated potential solution concepts. Below are the solutions I generated. My concept sketches were ultimately used when I pitched the product for funding.
Selecting an Approach
To select an approach from the many brainstormed possibilities, I created design matrices for the cooler housing, cooling unit, and energy storage.
Ultimately a traditional chest cooler, with a thermoelectric cooling unit, and a 5 volt rechargeable battery was selected as the best design to address the engineering requirements.
Pitch For Funding
With a design selected, the team presented and defended our product proposal for funding at Rev Start-up Accelerator to a panel of judges. I created the slide deck used by the team, which can be viewed below. On pitch night, after a successful presentation, our team was awarded the full amount of our ask: $500.
Proof of Concept
Using the thermoelectric principles gathered from our research, I designed a proof of concept thermoelectric cooling unit. The unit is made up of a thermoelectric plate sandwiched between a heat sink and fan on either side. On the outside, the heat sink transfers the heat generated by the plate to the ambient air. The interior heat sink and fan circulate the internal air to draw the internal heat to the cold face of the thermoelectric unit. The components are held together with two 3D-printed housings. This unit was mounted to an insulated lunch box as a test chamber.
To test this proof of concept, I wired the cooling unit and fans to a 5V power supply using a breadboard. The unit was secured to a test chamber with the cooling side facing inward and the other side facing outward. I used two temperature probes to collect data. One was placed inside the test chamber to measure the interior temperature and the other was left outside to record the ambient temperature for comparison.
Upon testing this design, the internal temperature was successfully decreased by about 6 degrees Celsius. However, after around 4 minutes, the internal temperature reached a minimum and the internal temperature began to increase again. This was a good indication that the system was not removing the heat from the thermoelectric unit fast enough and it was beginning to leech into the internal compartment.
Based on this data, I redesigned the cooling unit with a much larger heat sink and fan and added holes in the housing to allow for better air circulation and thus convective heat transfer between the thermoelectric cooler and the ambient air.
Testing with this new design, the cooler successfully reached 6 degrees Celsius, which is only 2 degrees higher than the product's target. To reach these target temperatures, I determined improved insulation as the primary requirement to prevent the removed heat from re-entering.
Refined Prototype
To refine the prototype, I worked with my team to construct a cooling chamber out of lightweight polystyrene foam board. The improved cooling unit was mounted to the lid of the cooling chamber.
I also wrote the code to integrate a raspberry pi with the cooler to add closed-loop control to the cooling. A touch screen allows the user to set the internal temperature of the cooler. While an internal thermometer reads a temperature above the desired temperature, the cooling unit is activated. If the temperature is below the desired temperature, the cooling unit is turned off.
I also added a rechargeable portable battery was also added to the design to allow the prototype to function as a stand alone unit.
The total cost of the final prototype was $104.76.
Reflection
While I am proud to have created a functional prototype, if given more time, there are many potential improvements. Referring to the customer needs identified earlier, there are certainly many steps to take this prototype to a marketable design.
While we were able to achieve our target temperature without and the prototype is portable in the sense that it is lightweight, future design iterations are needed to make the cooler easier to transport in a hiking/backpacking context. The team discussed exploring more novel soft insulating materials to create a cooler at the intersection of a chest and bag to allow the cooler to fit in irregular spaces. A carrying strap would also need to be added for an ergonomic way to carry the cooler.
While we successfully introduced temperature customizability, the team has yet to test for battery-life and durability in the outdoors. Drop testing, water resistance tests, and battery-life tests will need to be preformed and changes made to optimize these properties.