Hot Off the Grill: Dishing Up Energy Saving

Mar 16, 2013 by

Hot Off the Grill: Dishing Up Energy Saving

Overview 

Denny’s Restaurant got its start in 1953 as a doughnut shop in Lakewood, Calif. Today it is the largest family-service restaurant in America, with over 1,600 locations. While the chain is known for its Grand Slam breakfast, that isn’t the only good value being served at Denny’s these days—especially in the Chicago suburbs, where Denny’s is focused on saving energy costs.

According to the ENERGY STAR® program, restaurants consume, on average, 2.5 times more energy per square foot than other types of commercial buildings. It’s not hard to believe when one considers the dishwashers, refrigerators, ovens, hoods, fryers, toasters, microwaves, computers and lighting in each location.

Joe and Susan Terrell, franchisee owners of two Denny’s restaurants outside of Chicago, had energy-saving opportunities in mind when building their new Joliet, Ill., location. Their goal? To obtain Leadership in Energy and Environmental Design (LEED) Gold Certification from the U.S. Green Building Council (USGBC), and they’ve put a lot of resources into making that happen. Already, this Denny’s location is the restaurant chain’s first LEED-certified restaurant, and one of the few LEED buildings in the restaurant industry. Being a 24/7 operation open 365 days a year meant that implementing a way to save energy costs could really have an impact on the bottom line.

Water Conservation 

Joe Terrell says that he will only consider putting an appliance in his kitchen if it is ENERGY STAR rated. He first focused on saving water with the purchase of an energy-efficient dishwasher. From an operational standpoint, his appliance is typically one of the most expensive pieces of equipment to run in the kitchen. Installing an ENERGY STAR qualified model saves, on average, 25 percent more energy and water efficiency than standard models. The Terrells’ new unit reuses the final rinse of its dishwashing program as the first wash. This feature reduces water usage by 300,000 gallons of water per year. At a cost of $7 per thousand gallons of water, Terrell estimates his restaurant saves $2,100 annually.

The use of a high-efficiency pre-rinse spray valve is one of the most cost-effective energy-saving devices available to foodservice operators—and the most easy to install. Typical spray valves can release hot water at a rate of 3 to 4 gallons of water per minute (gpm), while common high-efficiency units like the one installed at the Denny’s Joliet location sprays only 1.6 gpm or less, without sacrificing cleaning power. In this Denny’s restaurant, the 60-psi high-pressure sprayer used for the

pre-wash dish cleaning saves an additional 30,000 gallons of water per year, or $210. That saving does not include the cost to heat the water or factor in the cost of the chemicals used in the wash, which are also reduced by using this pre-wash device.

In addition, Terrell installed tamper-proof aerators on all faucets to reduce water flow from 5 gpm to 1.5 gpm. With the aerators eliminating dripping water, the restaurant is saving 90 gallons of water per day, or $230 per year per dripping faucet, according to Terrell.

Most restaurants use a 100-gallon water tank, which is continuously heated to a temperature of 125 to 140 degrees Fahrenheit. At this Denny’s location, instead of the traditional water heater, Terrell installed a high-efficiency water heater with a flash heating system, which provides instant hot water to save energy. It heats only 17 gallons of water at a time; when the hot water runs out, the water tank heats more within minutes. The restaurant saves money by not having to continuously heat water and has not run out during its normal operations.

Saving Costs in the Kitchen 

One of the reasons why Terrell chose a Traulsen G-Series refrigerator for his kitchen was because this ENERGY STAR listed solid-door model can save up to 45 percent per year in energy costs. Below are other kitchen appliances that saved money for the Denny’s kitchen:

– A fryer equalizes the temperature of the grease to save cooking time. Additionally, the fryer oil is recycled three times before being sent out to be used as biofuel.

– An energy-efficient Hobart Toaster is on duty around the clock.

– The grills, griddles and fryers are ENERGY STAR rated, saving $11 per day in natural-gas costs.

– An ice machine with a compressor installed on the roof reduces the amount of heat generated in the kitchen.

– An exhaust hood monitors the temperature of the grill below it and adjusts fans accordingly. When the grill is at a lower temperature and less air needs to be vented, the fans throttle back accordingly. When the temperature climbs, the fan speed increases. With air vented only when it has to be, the HVAC system isn’t taxed as much, which reduces the use of air during the slower periods of business.

– Efficient storage-saving devices, including gliding storage shelves, are used for dry goods and perishables.

 

A Brighter Opportunity 

Extensive use of natural daylight through skylights and high-efficiency lighting brought a saving of 83 percent over the restaurant’s traditional lighting costs. Some of the measures are highlighted below:

– Installing 4-foot-by-4-foot skylights throughout the restaurant and kitchen. The Amish-made skylights use mirrors to bring in natural light.

– Installing LED lighting and CFL fixtures inside and outside the restaurant.

– A daylight harvesting system measures the amount of light needed and adjusts the lighting accordingly.

 

Additional Initiatives 

Other energy-saving initiatives incorporated into this Denny’s location:

– Energy-efficient walls, with an R-30 efficiency value, and a roof with an R-60 efficiency value. These thermal ratings are much higher than normal for the Chicago area and bring increased thermal resistance.

– Using recycled materials in the drywall and drop celling.

– Installing a high-efficiency HVAC unit on the roof.

– Painting the rooftop with a highly reflective white elasticizer instead of the typical black. On an 80-degree day, the temperature of a white roof is 80 degrees, and a black roof’s temperature can reach 128 degrees. Having the white roof means that the cost of cooling the air to 72 degrees for the comfort of the guests is much lower.

– Painting the walls with low-VOC paints.

– Installing carpet that is made of wool, a rapidly renewable resource.

– Site planning included a stormwater retention pond.

 

Results 

Terrell, who continues to find new ways to earn more green by being green in his restaurants, enjoys sharing his findings via tours or by speaking at industry events. He says that people often ask him how much more it costs to build a location with energy-efficient products compared to building a location to regular standards. Terrell takes pride in sharing that this 4,100-square-foot Joliet location was built at a cost of $800,000, which was, in fact, under budget compared to what the chain usually spends on locations at the end of a strip mall. When he compares his energy saving in Joliet to his Mokena, Ill., location, Terrell says that his utility costs are $20,000 less per year at the Joliet location, even though the restaurant is 20 percent bigger than the Mokena location. The cost of installing energy-saving devices shows a rapid ROI. When such devices are installed in new construction, Terrell says the cost is often minimal.

A former accountant turned green evangelist and member of the USGBC, Terrell says there are many things that people can do to experience this type of saving.

“For me, it’s all about sustainability. Right now, of the 20,000 LEED-certified buildings in the world, only 38 restaurants have certification,” says Terrell. “Imagine if every restaurant in America could recoup the type of savings that we are.”

 

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