As you may already know from my earlier posts, I am a design engineer for Marvel and one my pet projects was our new keg cooler (also known as kegerators) redesign. I would like to share our new design and explain just exactly how we made what’s known today as the world’s best beer dispensers – and why it matters to you.
Engineers Loves a Challenge
In 2012, the Department of Energy released a new mandate for household refrigerator energy consumption (the yellow tag you see on all of your electrical appliances), requiring a 30% reduction in energy from the previous energy guidelines. That kind of change in the engineering world is a big deal and it required manufacturers to completely retool their products. Faced with this change, we decided to look at it as an opportunity (that word can also mean a heck of a lot of work!) to redesign our keg cooler from the ground up, so… (drumroll, please)
Not only was our goal to meet the new Department of Energy (DOE) standard, we were determined to achieve an ENERGY STAR® rating, which is an additional 10% less than the DOE rating.
Not All Keg Coolers Are Created Equally
As you shop around for a keg cooler you might notice that not everyone has a yellow tag. That’s because keg coolers are exempt from the DOE Regulations. But we chose to include our beer dispensers, because with ours you can use it as a refrigerator! Let’s face it, most people do not use a keg cooler year round so justifying the purchase is hard to do. Designing it to be a refrigerator for 50 weeks a year has its advantages!
Step 1: How to Make a Square Peg Fit in a Round Hole
First, keep in mind that the keg (1/2 barrel) did not change in size. And the space for the keg cooler in your kitchen, man cave, or rec room also didn’t change in size (fit under the counter), so just adding insulation was not as easy as it sounds. Make it smaller on the inside and the keg won’t fit. Go larger on the outside and the unit won’t fit into the hole. See the dilemma? Plus, we kept in mind the growing desire of keg cooler owners to be able to fit two smaller kegs in the same unit. And then there’s the new tall quarter keg, along with the 1/6 barrel that’s becoming more prevalent. Then there are people like me who would like to dispense three batches of home brew at the same time. At the same time we needed to increase the foam thickness between the warmest and coldest spot in the unit which is the floor. Where was all that stuff going to fit? Well, we made it happen.Our designers balanced fitting kegs, heat load and moving air on the high side (Compressor, Condenser, and Condenser Fan) in and out through the toe grille to create a keg cooler we were all proud of.
Step 2: Working with Non-Engineers (aka Marketing)
Then our Marketing Team suggested an active drain system. We created a drain sump under the faucet that will drain your drips away into a plastic bottle inside the refrigerated area. We chose the cooled area over outside to minimize mold growth. And, the sump grate is flush with the top of the unit to keep your mug from tipping on the edge.
Step 3: Keeping Our Customers in Mind
We included an option to store the CO2 tank either inside or on the back wall with a hole in the rear wall to route your gas line. This allows you, the consumer, to pick what is best for you, whether it’s an additional CO2 tank or including an external nitrogen tank.
Step 4: The (Awesome) Technical Stuff
We also increased the temperature range for darker ales (34 to 46°F). To go any warmer it would compromise the energy calculation for DOE (don’t ask, it is a long story).
And the biggest improvement above all others is the performance. Performance in the refrigeration world refers to temperature stability, temperature gradient, and temperature swing with various loads. Remember that this unit was designed for both hold kegs and food. That creates two very different air flow patterns, which creates different heat loads and temperature sensing. Proper temperature sensing is important so if your set point is at 38°F, the air in the refrigerator is actually at 38°F. That might sound easy, but there’s a big difference between a 100 pound stainless steel keg blocking the air, versus two shelves with just a few cases of beer.
Step 5: Building a Better Mousetrap
Another feature we do differently is a better insulated draft tower. Many of the competitive units add extra air flow to the draft tower to keep the beer lines cold. We didn’t want to go down this path for two reasons. First, it complicates the energy calculation and testing. Since we are both a refrigerator and keg cooler it has to pass the refrigeration tests first. If you are blowing cold air up a draft tower that is not there, things go higgly-piggly. Second, if you super-chill the tower you end up with a sweaty tower and that can lead to corrosion issues and loss of heat. Our solution was to add insulation to the tower to keep the beer cold. And in reality there is less than one ounce of beer in the tower at any time.
As you might guess from this blog, I am a little proud of our new keg cooler. Well, yes I am. Some might say I am a little biased. But I say, show me another 24-inch keg cooler that can house a half-barrel, or three corny kegs, that exceeds DOE energy standards, can be built-in, and looks good while doing it. Well, I am waiting…
Take Care and Drink Wisely,
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