Although the actions covered in this section require more extensive implementation, they can dramatically increase the efficiency, comfort, and safety of your restaurant. Ask your local utility’s representative for more information about initiating such projects.
Commissioning is a process in which engineers observe a building’s energy systems and perform a tune-up to ensure that they are operating appropriately and efficiently. Doing so can lead to reductions of 10 to 15 percent in annual energy bills. When this process is applied to an existing building that has not been commissioned before, it is called retrocommissioning. When it is applied to a building that has been commissioned before, it is called recommissioning. Recommissioning is recommended every three to five years to maintain top levels of building performance. In restaurants, commissioning also allows you to evaluate airflows between cooking and dining areas and to use that information for implementing air-pressure balancing measures. Commissioning usually costs between 5 and 40 cents/ft2.
High-efficiency kitchen equipment. Cooking equipment, coolers, and dishwashers are energy hogs in a restaurant—high-efficiency cooking equipment can be 15 to 30 percent more energy-efficient than standard equipment. The benefits of purchasing an energy-efficient model go beyond energy savings, as well: The same measures that make the units more efficient can also lead to better performance. For a list of Energy Star–qualified products and an online calculator that can help you determine savings for your particular upgrade, visit the commercial food service section of the Energy Star web site.
Smart vent hoods. Commercial kitchen exhaust hoods remove a lot of indoor air, forcing the ventilation system to draw outside air into the kitchen to make up for those high airflows. In climates where the kitchen makeup air is conditioned, that conditioning can account for up to one quarter of the entire energy use of a food service establishment. Intelligent, variable-speed hood controller systems can significantly reduce energy costs in your kitchens. A photoelectric smoke or heat detector determines when and how much ventilation is needed and activates the exhaust fan at the proper speed, compared to the continuous operation of the fan in a traditional vent hood. In appropriate applications, this technology yields a one- to two-year simple payback.
In 2004, researchers from California’s Food Service Technology Center (FSTC) monitored energy use and demand before and after the installation of this technology in a 30-foot canopy hood at the Inter-Continental Mark Hopkins Hotel in San Francisco, California. The researchers found that it reduced electrical demand from 14.0 kW to 5.3 kW, for a savings of 8.7 kW. Projected annual electrical cost savings for the fans came to $9,910 (based on $0.13/kWh). Reduction in makeup airflow reduced the annual cost of natural gas for heating by $9,460 (based on $0.80 per therm). The total savings of $19,370 resulted in a payback period of less than one year. An additional benefit to kitchen staff is the noise reduction that frequently accompanies installation of a variable-speed hood controller.
Induction cooking. Cooking energy consumption can be reduced 10 to 20 percent by using an induction cooktop rather than a conventional cooktop. That’s because induction cooking transfers 85 to 90 percent of the energy directly into the cooking pan, compared to gas cooking or electric cooking which are only about 55 or 70 percent efficient respectively. Because they’re more efficient, induction cooktops generate less ambient heat, which can reduce cooling bills, create a more comfortable kitchen environment, and eliminate safety issues associated with open-gas flames or hot electric surfaces. Induction cooking also heats food more quickly than gas, provides very stable cooking temperatures, and the cooking surfaces are easier to clean than those for conventional stoves.
Connectionless steamers. Replacing inefficient steam cookers represents one of the most substantial opportunities for energy savings in a commercial kitchen. There are an estimated 205,000 compartment steamers in food service operations nationwide. Of these, most are traditional units that rely on a boiler to vaporize a constant inflow of water. The FSTC estimates that 60 percent of the current compartment steamers in use—or 123,000 units—waste enough water and energy to warrant replacement. Self-contained, or “connectionless,” steamers provide the most efficient alternative to conventional units, and they offer combined annual water and energy savings of up to $6,000 per machine.
Connectionless steamers are not attached to water lines. Instead, they rely on a manually filled reservoir that sits in the bottom of the steamer. Unlike traditional steamers, connectionless units recirculate the steam rather than continuously venting. The result of this closed system is a substantial savings in both energy and water. In all, connectionless steamers use about 2 gallons of water per hour—compare that to an average of 40 gallons for traditional models. Over the course of a year, the water savings achieved by replacing inefficient steam cookers with an equivalent-sized connectionless model can exceed 150,000 gallons. If all the inefficient boiler-based models were replaced nationwide, the annual water savings would be about 20 billion gallons—enough to supply roughly 210,000 households. The energy savings are also striking. A highly efficient connectionless steamer could save up to 11,000 kWh over a conventional model. If the entire food service industry replaced conventional steam cookers with highly efficient machines, the energy savings would reach 1.25 billion kWh—equal to the electricity consumption of about 115,000 households.
Ice makers. The energy efficiency of new ice makers has improved considerably over the past decade, and there are now many efficient models to choose from, some of which provide substantial energy savings with little or no incremental cost over less-efficient models—a win-win situation. With new state and federal standards coming into effect, the number and diversity of energy-efficient ice makers will continue to increase.
In some cases, high-efficiency ice makers have little or no incremental cost versus less-efficient models. For example, a search for air-cooled ice makers with approximately 1,200 pounds of capacity showed that a model meeting the Consortium for Energy Efficiency (CEE) Tier 1 standards was more expensive than its less-efficient counterparts at $120 (2 percent) more than a baseline model; models meeting the Tier 2 and Tier 3 standards cost $250 (3 percent) and $350 (5 percent) less than the baseline model, respectively.
When you’re shopping around for a new ice maker, be sure to pick a machine with the right capacity. Oversizing an ice maker can increase energy consumption due to excessive standby losses. On the other hand, larger ice makers generally consume less energy per unit of ice than smaller ones. It is important to pick a unit that most closely matches your quantity requirements. Ice machines are designated by the amount of ice that they can produce in a 24-hour period, under reference conditions of 70°F (21°C) ambient temperature and 50°F (10°C) inlet water temperature. Typical sizes are 250, 400, 500, 650, 800, 1,000, 1,200, and 1,400 pounds per 24 hours, but machines are available that make several tons of ice per day. Actual capacity varies with both ambient temperature and water temperature. Manufacturers usually recommend using the capacity listed at the test conditions used by the Air-Conditioning and Refrigeration Institute (ARI): 90°F (32°C) ambient air and 70°F (21°C) water. Selecting equipment based on the capacity at those conditions will ensure that adequate ice can be produced under most conditions encountered in operation.
New U.S. federal and state standards will continue to push ice-maker efficiency upward. Federal energy-efficiency requirements taking effect in 2010 will be the same as the current (voluntary) CEE Tier 1 standards. California’s 2008 energy-efficiency standards for commercial ice makers are also the same as the current CEE Tier 1 standards.
Evaporator fan controllers in coolers. Nearly all walk-in coolers have forced-circulation evaporators that contain motorized propeller fans. These fans run continuously, despite the fact that full airflow is only necessary 50 percent of the time. Inexpensive walk-in cooler controllers are now available that slow these fans when full cooling capabilities are not necessary.
Demand-defrost kits. On average, timer-based defrosters (used to defrost the ice that accumulates on the evaporator coils during operation) account for about 20 percent of the total energy consumption of walk-in freezers. Demand-defrost systems, which initiate defrosts only when they are needed, can save significant amounts of energy by reducing the number of defrost cycles. Independent tests show that the more advanced demand-defrost controllers can reduce defrost cycles by as much as 40 percent compared to defrosters with timers—saving from $150 to $3,000 annually on energy costs depending on the size of the freezer. In addition, these controllers can help maintain the quality of products kept in the freezer because fewer defrost cycles translates into a more constant temperature in the freezer. One study found that for a 1-ton walk-in freezer, which typically consumes 4 megawatt-hours annually to run the electric defroster with a timer, a demand-defrost controller will save approximately $150 annually in energy costs. Given that these systems typically cost about $400 to $600, the demand-defrost controller will yield a payback of about two to four years.
Switch to compact fluorescent lamps. Replacing incandescent bulbs with compact fluorescent lamps (CFLs) not only saves energy, but the bulbs also last much longer, so they save on maintenance. One restaurant owner replaced 20 100-watt bulbs with CFLs that used less energy, helping the restaurant to save more than $400 per year. CFLs are now available in 2,700-kelvin models that produce a warm color tone similar to that of incandescent lamps. You can also adjust their light intensity by installing dimmable ballasts. Just be sure to use CFLs in appropriate ballasts, especially if dimmers are in the circuit.
Install T8 lamps and electronic ballasts. If your facility uses T12 fluorescent lamps, relamping with the latest T8 lamps and electronic ballasts can cut 35 percent off your lighting bill. Adding specular reflectors, new lenses, and occupancy sensors or timers can double the savings. Paybacks of one to three years are common.
Use daylighting controls. Daylighting control systems use sensors and either switches or dimmers to adjust electric lighting levels in response to available daylight. These systems offer the potential to cut energy use, reduce peak demand, and create a more desirable indoor environment in your restaurant, but in many cases they fail to live up to that potential. The keys to optimizing these systems are combining good design with commissioning, effectively coordinating the efforts of many building disciplines, and training staff on how to use the systems. In addition, new technologies for daylighting control are being developed to make daylighting systems easier to install and calibrate.
Illuminate with LEDs. Replace incandescent exit signs, exterior signs, colored accent lights, downlights, and menu boards with ones lit by light-emitting diodes (LEDs). LEDs direct light very effectively and come in many colors, which make them a good candidate for restaurant applications. Although initial costs for LEDs are high, the lamps can last 5 to 10 years, so you’ll also save on maintenance costs.
- Exit signs. These signs must be lit both day and night, which can take a bite out of a restaurant’s budget. A single LED exit sign saves on the order of $45 per year and will shine brightly for 5 to 10 years, which can significantly reduce material and labor costs as compared with standard incandescent models.
- Downlights. In the dining room, recessed downlighting fixtures equipped with white LEDs can save considerable energy compared with an incandescent light source. LED downlights are also fully dimmable and, according to many, provide superior light quality. Just make sure you purchase a trusted LED downlight, because this is a relatively young niche industry that has been the subject of occasional inflated vendor claims.
- Open signs. LEDs are the best choice for replacing neon “open” signs—they use 80 percent less energy than neon but have about the same initial cost. The majority of LED models run from $99 to $150 for a plain sign; the majority of neon models fall into the $50 to $150 price range. Over a 10-year period, however, total life cycle costs for an neon sign could run about $480, whereas a comparable LED unit with a 10-year life would incur overall costs of about $170 (Figure 3).
Figure 3: Energy use of an LED open sign compared with a neon open sign
An LED open sign will save $455 in energy and replacement costs over its lifetime compared with a comparable neon open sign.
Use smart lighting design in parking lots. Many restaurants set their peak demand when they turn on lights in parking lots. And parking lots are often designed with far more lighting than most lighting experts recommend. Parking lot light levels may depend on local ordinances, but can generally be fairly low. The guidelines laid out by the Illuminating Engineering Society of North America (IESNA) suggest 0.5 to 5.0 foot-candles, depending on the level of activity and the potential hazards. Typically, an average of 1 foot-candle (or less) is sufficient. Not only is overlighting costly, it can be dangerous to drivers if their eyes cannot adjust fast enough in the transition from highly lit to dark areas.
When designing lighting for a new parking lot, consider low-wattage metal halide lamps in fixtures that direct the light downward, rather than high-pressure sodium lamps. Even with a lower wattage, you can safely use fewer lamps if this choice is made. Metal halide is less efficient than high-pressure sodium in conventional terms, but it puts out more light in the blue part of the spectrum, which turns out to be easier for our eyes to see under low-light conditions. LED lighting has emerged as an even more efficient parking-lot option than high-intensity lighting, however, since their high initial costs result in long payback periods, be sure to conduct a thorough analysis before you commit to LED lighting for your parking lot.
Install security lights. Security lights around the perimeter of many restaurants can consume prodigious amounts of electricity. By installing an inexpensive motion sensor, a restaurant can save about $130 per year on every 300-watt double-fixture floodlight on the property. Additionally, security lights integrated with a motion sensor can actually deter crime better than flood lights that are left on all night.
Water Heater Measures
High-efficiency water heaters. When replacement time comes around, upgrade your tank water heater—whether gas-fired or electric-powered—to a high-efficiency model. Though high-efficiency models often cost a little more up-front, they’ll save $400 per year in fuel expenses for a small establishment and substantially more in a large restaurant.
Tankless water heaters. High-efficiency tankless water heaters, also known as instantaneous or on-demand water heaters, heat water only when it’s needed and can save significant amounts of money and take up less space than traditional models. Tankless water heaters also have very long lifetimes—20 years compared to traditional water heaters’ 6 to 10 years. Their reduced maintenance and replacement costs go a long way toward offsetting the higher purchase price of a tankless heater, which can run from $1,000 to about $2,000, depending upon output capacity. Tankless water heaters do have one drawback: They provide hot water more slowly than conventional tank water heaters. This can slow the performance of equipment that are flow-dependent. This disadvantage can be overcome by plumbing multiple tankless units in parallel to provide the desired flow rate. In other applications, the lower flow rates available from tankless heaters are often adequate for the job.
Water-efficient dishwashers. High-efficiency dishwashers are distinguished by their low water consumption per rack for conveyer or door-type dishwashers (this may not apply to under-counter units). Purchasing or renting a dishwasher that’s certified by NSF to have a water consumption rating of less than 1 gallon per rack (this rating is available on the NSF web site) reduces the amount of water heating necessary. Low-temperature dishwashers use less energy than high-temperature units, but operating costs are about the same because of the cost of the sanitization chemicals required for low-temperature units. If you choose a high-temperature dishwasher, consider installing a gas booster heater instead of an electric one—depending on local energy prices, energy cost savings often more than make up for increased capital and installation cost.
Low-flow pre-rinse spray valves. Water heating in commercial kitchens accounts for nearly 10 percent of restaurants’ total energy use. Installing low-flow sprayers is the easiest and most cost-effective method of saving hot water in a commercial kitchen; it can reduce the amount of hot water required to wash dishes by 50 percent or more without compromising cleanliness or slowing down the dishwashing process. Low-flow spray valves, which discharge hot water at a rate no greater than 1.6 gallons per minute (gpm) at a water pressure of 60 pounds per square inch, are used to remove food scraps from utensils, pots, dishes, and pans before placing them in a dishwasher. Since January 1, 2006, all new prerinse valves sold have been low-flow, as required by the U.S. Energy Policy Act of 2005 (EPAct 2005). However, for facilities using older spray valves that are less efficient—with typical flow rates of 4 to 6 gpm—considerable savings are possible from switching to low-flow spray valves. According to the FSTC, substituting a low-flow spray valve for a valve flowing at 3 gpm for 2 hours per day will save over 43,000 gallons of water and $600 to $700 annually. The FSTC offers a free online tool that can help calculate cost savings from installing a low-flow valve on its web site.
Optimize makeup air. Kitchen ventilation systems represent one of the largest uses of energy in a commercial food service facility, accounting for up to 75 percent of the HVAC load. A new design guide, available on the FSTC web site, “Improving Commercial Kitchen Ventilation System Performance: Optimizing Makeup Air,” presents strategies for minimizing the impact that the introduction of makeup air will have on hood performance and energy consumption. A commercial kitchen ventilation system that is designed using the guide is not only likely to improve safety and comfort, it will also save a good deal of energy. One case study conducted in a typical restaurant found that applying the design guide’s recommendations reduced makeup air supply by 2,000 cubic feet per minute and annual commercial kitchen ventilation system energy cost (including makeup air fan energy, conditioning, and exhaust) by $4,000.