Jezell Lee - Rethinking the Conventional Fridge Shelf

Design and Human Factors: Rethinking the Conventional Refrigerator Shelf to Minimize Food Waste

INTRODUCTION

For my Design and Human Factors class, I helped re-design a conventional refrigerator shelf, guided by principles of UX and human ergonomics to steer users toward our overarching group goal of reducing food waste. Many of our group members were interested in health, nutrition, and sustainability, so we were able to easily agree on this topic. Our initial research indicated that more than 54 million Americans face food insecurity, a number that has only been exacerbated by the ongoing pandemic, and that US households waste almost 76 billion pounds of food per year, ironically also making the US the leading country for food waste.

MY ROLE

I was part of the design team and contributed to the conceptualized prototypes of our product. Due to the COVID-19 pandemic, the discussion and realization of this design project was conducted entirely online through weekly Zoom meetings, which in itself was challenging to coordinate due to the wide international spread of my team, as many of us were located in different time zones.

THE PROBLEM

Minimizing food waste—Our first discussion was mostly centered around the problem that we wanted to solve, namely the minimization of food waste with a focus on households. Because about half of the food in the refrigerator goes unconsumed, refrigerators became an important design framework of focus for our goal in reducing food waste. We wanted to provide more comfortable and convenient solutions for consumers, emphasizing ergonomics. We also wanted to increase the efficiency and convenience of refrigerator design and educate consumers about food waste, potentially altering their habits. We also conducted interviews with potential users and discovered that most foods that are thrown away are often forgotten about in the fridge, tucked away and unseen in the back. In essence, food is not consumed before spoiling, due to an inability to see that specific food item in time.

Ergonomics—Because we focused on efficient refrigerator usage as well as ergonomics as important frameworks for minimizing food waste, we wanted to address and explore the task of taking an item from the fridge and placing it back into the fridge. Using Kinovea to accurately capture the measured angles of our user's posture, we noticed that users of a conventional fridge shelf often have to adopt an awkward or strenuous posture when reaching for items in the back of the fridge, as shown below to the left. If this task is performed on a regular basis several times a day, it could result in health issues such as lower back, neck, and wrist pain. In this instance, the user was reaching for a carton of milk, but this could potentially be more dangerous if the lifted load was significantly heavier, like a filled crockpot. A REBA assessment (below right) yielded a score of 9, indicating a high risk posture that warrants investigation and a design intervention.

FINDING SOLUTIONS

Next, our group brainstormed various design solutions to our problem, using digital sticky notes. There were many different approaches, and we went with the idea that garnered the highest number of votes, or E, the plastic baggie hanger that can roll out like a drawer with other drawer-like shelves.

INITIAL CONCEPTUALIZATION

Our first design simply focused only on the Ziplock bag hanger, as visualized below:

1. A clear, reusable bag to oversee the items stored in the fridge. 2. A sliding rail to grab items easier. 3. A shelf/drawer storage space for extra space for storage 4. Grooves for bags to hold the reusable bags tight and steady.

But we soon realized that it wasn't feasible to put all refrigerated items into Ziplock or reusable bags, so we decided to re-shift our focus to include drawers that would also function as sliding shelves, so that users could pull them out without having to take on strenuous postures and still be able to see everything on their refrigerator shelves.

1. A protective barrier, so the items will not fall when the tray is moving. 2. A handle to comfortably pull the drawer out/into the fridge. 3. Sidewalls that are responsible for affixing the shelf to the refrigerator. 4. Moving mechanism: A roller on the two parallel metal plates.

These drawer/shelf hybrids are meant to be implemented as the middle and bottom shelves of the refrigerator, with the Ziplock ergonomic storage shelf at the very top. However, when users tested this, items would easily roll around the surface of the shelves and spill amongst each other. Some users would also slam the refrigerator door onto the shelves while they were still in their pulled out positions, causing damage to the shelf corners. To mitigate this, we decided to implement an anti-slip surface coating as well as padding for the corners, as seen below.

1. A protective barrier, so the items will not fall when the tray is moving. 2. A handle to comfortably pull the drawer out/into the fridge. 3. Anti-slip coating to prevent the contents from slipping or falling off. 4. Sidewalls that are responsible for affixing the shelf to the refrigerator. 5. Paddings at the back to dampen any possible impact with the back of the fridge. 6. Moving mechanism: A roller on the two parallel metal plates. 7. Padding around the front corners to dampen any possible impact with the fridge door.

I also drew the initial sketch to visualize our whole refrigerator design, completely outfitted with the Ziplock ergonomic storage shelf on top and the drawer/shelf hybrids in the middle and at the bottom:

After further testing and a more complete visualization, we explored possible beeping sensor placements, in order to prevent cognitive lapses while using the storage shelves. For instance, one user opened several shelves at once and hit his head on the top shelf after taking something out from the bottom shelf because he forgot that the top shelf was still pulled out. Some users also forgot to use the Ziplock bag shelf and just placed the bags onto the shelf rather than attaching them to their allotted grooves. Other users would close the refrigerator door onto the shelves, without pushing them back into their original positions, leaving them prone to damage. I then added the changes we made to the sliding shelf design, a Ziplock bag shelf label, and indicated possible placements for the beeping sensors in our next design iteration:

Ziplock Ergonomic Shelf Label

1. Top shelf can slide in and out of the fridge and has Ziplock bag holders below. 2. Slidable middle shelf displayed as sliding outward. 3. Second slidable middle shelf displayed in the fridge. 4. Paddings around the corners the shelves to minimize possible damage. 5. Possible sensor placements. 6. Ziplock instruction label indicating potential load limit, etc.

3D SOLIDWORKS CONCEPT

As addressed previously, our priorities are human interaction and ergonomics. With our improved design and a SolidWorks visualization, we can prevent possible use errors. The 2D drawings of the ergonomic Ziplock shelf and sliding shelves are included below:

There are two places we could place the beeping sensors to address several potential use errors:

1. Behind each shelf towards the end of the shelf pointing throughout the width of the main fridge compartment. This placement would address the first potential use error that is opening multiple shelves at once instead of opening them one by one to access the contents. By using separate sensors for each moving shelf and writing a simple computer program, a beeping sound can be triggered when a shelf is opened without another one being closed. This way, users would be warned to be mindful when trying to open multiple shelves at the same time.

2.) Below the top left front corner of the fridge towards the left edge. The sensor would point down vertically throughout the height of the main fridge compartment. The idea behind this specific placement was to address the third potential use error indicated in the above table that is closing the fridge door before pushing the shelf back into its original position. In this case, the sensor can be programmed to beep if the shelves are not back in place in the fridge and the fridge door is approaching towards the main fridge compartment (a minimum angle between the fridge door and main compartment can be chosen to trigger the sensor upon the closing motion). We were able to demonstrate the second sensor placement idea on SolidWorks. Please refer to this animation video to see how the vertical sensor can be triggered with the opening and closing motion of one of the shelves.

Sliding Shelf Animation

EVALUATION OF ERGONOMICS

We again used Kinovea to measure the angles of various back, neck, and wrist postures that a user would adopt when reaching for items using our sliding shelf design. As pictured below, the angles are far less steep (in comparison to what they were before) and the postures are also less strenuous, further underscored by the re-assessed and improved REBA score of 3, indicating that the task is low risk and may need to be evaluated for change, but not immediately.

FUTURE WORK

In the next design iteration, we could potentially add additional shelving units onto the interior of the fridge door. The current design’s amount of shelf and storage space could work for couples or people living on their own, but larger families or co-living situations might find the available space to be limited. Adding a tech-enabled feature such as a sensor connected to a mobile app would facilitate tracking of the items inside a fridge. This could reduce the amount of food waste substantially as users would see what is inside the fridge while grocery shopping, to avoid overbuying and prevent eventual food spoilage. Another idea could be to add enclosed drawers equipped with a device that monitors ethylene gas levels specifically for fruits and vegetables so that users would know precisely when their food would be ripening or close to expiring. Because design, edge cases, and the opportunity to improve are endless, we would ultimately have to continuously evaluate the needs of our users and constantly reiterate to meet those needs.

To read the full-length report, please click here.