Energy efficiency in the kitchen (part 2)

Commercial kitchens are high energy users, consuming roughly 2.5 times more energy per square foot than any other commercial space, according to the US Environmental Protection Agency (EPA)Of that, as little as 40% is used in the preparation and storage of food, says the UK’s Carbon Trust; much of the wasted energy is dispersed into the kitchen. The technology exists for dramatic reductions in energy consumption, resulting in carbon-footprint reductions and significant cost savings. The EPA claims that restaurants that invest strategically can cut energy costs by between 10%-30%.

There are two areas of real concern in commercial kitchens: equipment used is often only 50% efficient; and low capital cost drives the choice of equipment with little consideration for the whole life-cycle cost.

Dishwashers

Pass-through dishwashers are the energy-hogging workhorses of many professional kitchens but the new generation has lots of energy-saving features. Choose a dishwasher model with a heat recovery condenser device to reuse waste hot water to heat the incoming supply of water. The latest dishwasher models also have reduced-size wash tanks, more efficient wash and rinse pumps and better water filtration technology, which consume less energy while improving the wash. Improved pump technology and better design of rinse arms and a reduction in the volume of required rinse water cuts water and energy consumption while improved insulation also makes it more efficient.

Refrigerators

Refrigeration running costs have improved significantly thanks to better insulation, new coolants, and remote condensing units, where cabinets and coldrooms are powered from one system, usually located outside.

• Site fridges and freezers away from cookers and keep coldroom doors closed so they do not have to work harder to maintain the desired temperature. Ensure they have plenty of ventilation and that staff do not inadvertently block ventilation panels.
• Avoid overloading a fridge/freezer, which affects airflow, reducing the cabinet or coldroom’s ability to chill effectively.
• Install door closers or alarms to prevent employees from accidentally leaving fridge/freezer doors open.
• Don’t keep frozen foods at temperatures colder than needed - increase the temperature of frozen food and product stores from -25°C to -20°C and save 10% of the refrigeration energy.

The latest refrigeration products offer up to 50% energy savings. They feature advanced electronically commutated motor fans, circuit design that optimises performance and improves air movement delivering much lower energy consumption, high density foam for better insulation, heavy duty gaskets to reduce the chance of heat getting in through the door, self-closing doors, hydrocarbon refrigerant, automatic shut-down on ice-making equipment, and fan cut-out switches when the door is open.

Intelligent controllers, such as those found on selected Williams refrigeration equipment, offer up to 15% in energy savings by detecting changing situations and altering the way the refrigeration system operates to ensure that energy use is kept to a minimum. Demand defrost controls are more economical to run because defrosting is initiated only when required via an infra-red sensor that measures the temperature or pressure drop, frost accumulation and humidity.

Lighting

• Use modern sensors, including PIR (passive infra red), which can detect movement over a range of 12 metres. Microwave sensors have a greater range. Integrating these sensors into existing systems can reduce costs by 30%.
• Replace old fluorescent tubes (20% deterioration in performance is possible over three years) with the T8 models if possible. Also ensure they have a “tri-phosphor” coating, which will reduce energy consumption by 10% and improve the quality of lighting over its lifespan.
• Replace tungsten bulbs with compact fluorescent lamps (CFLs) to reduce consumption by up to 80%. They last up to eight times longer and use about 75% less energy.

Ventilation

The kitchen ventilation system represents one of the largest consumers of energy in the kitchen, often because it operates at full capacity even during idle times. EDF Energy, a UK energy supplier, has estimated that while 50% of the cost of a meal bought in a restaurant can be contributed to the cost of energy, 30% of this energy cost is taken up by kitchen ventilation alone.

While significant energy savings can be achieved by purchasing energy-efficient appliances, equally important is establishing simple operational and maintenance procedures. These include:

• Switching off equipment when it’s not needed and providing good training so staff know how long a piece of equipment needs to reach the desired temperature, avoiding unnecessary energy wastage.
• Regular maintenance of equipment to ensure that appliances perform most efficiently. Something as simple as cleaning coils and keeping them dust-free will keep a refrigerator running more efficiently.
• Closing doors Leaving open oven or fridge doors consumes significant additional energy to bring the equipment back to a safe or desired temperature.
• Checking thermostats Check and adjust thermostats on ovens, fryers, etc., as it’s not unusual for them to lose accuracy over time.
• Optimising equipment capacity Choose only the size of product to maximise output while minimising energy usage.

Excerpt from ‘Green Hotelier’

•  Share this page