CASE STUDY | MCDONALDS, WALT DISNEY WORLD McDonalds claims its operation at Walt Disney World in Florida is the first net zero energy fast-food restaurant in the world. Cyclone Energy Groups Benjamin Skelton explains how innovative ventilation strategies suited to the subtropical climate helped the restaurant achieve actual net positive energy Greening the golden arches T he original concept for the Walt Disney World campus in Florida included a new community that would serve as a centre for American enterprise and urban living. Walt Disneys death meant the vision of a new city was never realised, but the concept was reprised in the Epcot theme park, which opened in 1982 and showcases modern innovation. Its been wildly popular since it opened and is the fourth most visited theme park in North America. It is fitting, therefore, that McDonalds designed and built the worlds first net zero energy fast-food restaurant on the Walt Disney World campus. The all-electric building has achieved more than 105% net positive energy for 12 consecutive months, thanks to a roof-mounted solar photovoltaic array. Quick-serve restaurants have very high energy use intensity and, with a 24-hour operation, some creative engineering was required to minimise loads. Cooking appliances consume 55% of the buildings annual energy, while building ventilation is the second-largest load. The majority of ventilation is replacement air for the cooking hood exhaust system, which runs 24 hours per day. To minimise kitchen exhaust, the kitchen hood exhaust system uses cooking demand-based ventilation controls. These monitor heat, grease and 38 October 2023 www.cibsejournal.com smoke, and adjust exhaust rates to maintain effective capture and containment. Quick-serve restaurants have large fluctuations in service and have to provide meals to customers on demand. A typical restaurant will keep their cooking lines hot 24 hours a day, so they can react instantly to an influx of customers. This is not only a major energy consumer, but it also adds significant cooling load and keeps the kitchen hood demand-control system from going to minimum flow. At the Walt Disney World restaurant, McDonalds deployed a new technology in quick-serve cooking that allows an entire line to go into idle mode and rapidly switch to ready when required. This location handles an extraordinarily large number of customers given its proximity to the theme park and has a very large kitchen to handle the demand. There are three cooking lines and being able to bring them to an idle state during lower demand times significantly reduces ventilation and energy load. Kitchen pressure is held at a 5% negative to adjoining spaces to keep kitchen odours contained. Having a variable exhaust system means the kitchen makeComfort is maintained in the outdoor area 58% of the time annually between 6am and 6pm