Transcript
Cook up some energy savings
in your restaurant kitchen
For more information visit
www.eskom.co.za/dsm
Issued by: Demand Side Management Department February 2009
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Information Guide
Eskom Holdings Limited Reg No 2002/015527/06
2 www.eskom.co.za/dsm
Saving energy in a commercial kitchen Energy-efficient commercial cooking In a typical restaurant, cooking appliances account for about 12% of the monthly electricity bill. The information in this brochure will help to provide some insight into the electricity costs associated with running a sit-down or a fast food restaurant. Even if food preparation is only a small part of the activity at your eatery, energy-efficient cooking appliances can reduce energy costs. Fortunately, there are many ways to save energy without spending a lot of money.
Heating,Ventilation & Air Conditioning (HVAC) Heating,Ventilation & Air Conditioning (HVAC) - Set up a routine maintenance schedule:
Clean or replace air filters.
- If central air conditioning is used cool down the building, run
- - - -
Check compressor oil levels. Inspect for refrigerant leaks.
of cooking equipment and appliances. - Improving air circulation. Food cooks more efficiently in ovens where the air can circulate freely, so don’t lay foil on the racks. If possible, stagger pans on upper and lower racks to improve air flow. - Not preheating ovens for longer than the manufacturer’s recommendation; usually 10 - 15 minutes. Letting the oven
- Turning the oven off a few minutes before food is ready.
- If you’re ready for a new water heater, consider an instant
The heat inside the oven finishes cooking the food. - Checking your oven temperature. Use a separate oven thermometer to ensure that your oven control is accurate. - Trying to schedule the usage time of the oven over the busiest times in the restaurant so that it will always be full when you use it.
regular metal pans.
all the while. Only preheat your oven when you’re baking,
- Choosing an efficient oven. The efficiency of ovens can vary
and use the smallest oven possible for small batch jobs.
widely. A lot depends on how they’re operated but there are
- Making sure the seal on the oven door is tight.
still general comparisons that can be made. The following
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setting that will still supply you with enough hot water. - Insulate the water pipes leading from the water heater.
any faster and it might even damage the oven, wasting energy
- Cleaning out the burnt bits of food at the bottom of the
Experiment within the 50°C – 60°C range to find the lowest
sealing properly.
oven temperature that is 14°C lower than you need for
door to check on food.
- Lower the temperature settings on water heater.
The accumulated muck can prevent the door from
costs. Setting a high preheating level won’t heat the oven
Using an oven timer will help you to avoid opening the
Water Heating spare by adding more insulation.
stove, especially where the door seal meets the stove.
- Using ceramic or glass pans will allow food to cook at an
door is opened about 20% of the heat is lost.
in the day.
the touch, you will save money and have more hot water to
preheat for any longer will needlessly increase your energy
- Avoiding opening the door while baking; each time the
the fans out of business hours and set them to cool later
- Insulate your water heater. If your water heater feels warm to
This fact sheet will focus on the energy saving opportunities in these major groups of appliances as well as savings that you can make with your environmental energy users such as lighting, water and air conditioning units.
- Implementing a schedule for the start up and shut down
Choose heat pump or reverse cycle type air conditioning instead.
Lubricate motors, pumps and fans.
You can increase the energy efficiency of your ovens by:
- Avoid using air conditioners with electric element heating.
Regularly clean and vacuum easily accessible components.
As a general rule, commercial cooking operations can be grouped into four major categories:
Saving energy with your ovens
- If you’re buying a new air conditioner, choose a model with an Energy Efficiency Ratio (EER) of 10.0 or higher.
- Turn off HVAC equipment when the building is unoccupied.
Check fan belts.
Ovens Stove tops Fryers Broilers
The room will cool just as fast.
table provides a comparison of the efficiency and relative operating cost of the different types of ovens.
- Seal off unused areas and reduce or eliminate heating or
water heater. These models can save as much as 20% - 30%
cooling to these areas. Storage rooms, warehouses and
of the cost of heating.
other unoccupied areas are great places to start. - Keep exterior doors closed as much as possible. Don’t heat or cool the outdoors. - Carry out preventive maintenance of rooftop equipment. Replace HVAC filters at least once every three months, insulate rooftop refrigeration lines, clean the condenser coils and shade coils from the sun if possible. - Install a ceiling fan in the largest room of your facility. This will allow you to lower the setting on your air conditioner by 3°C - 6°C, which will save up to 25% of your cooling costs. (Be sure to reverse the fan rotation to clockwise in winter!) - Clean the filter screen once a month. This will reduce fan usage and save electricity. - When turning on your air conditioner, avoid using the coldest setting. Let the air conditioner warm up for a while before lowering the temperature setting.
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General energy saving in the kitchen Refrigeration - Maintain freezers and refrigerators to improve efficiency. Clean cooling coils several times a year. Make sure doors seal tightly and repair any damaged door seals. - Turn off the reach in refrigerator door heaters whenever possible. - Keep refrigerators 10cm away from the walls for proper air circulation. - Set the defrost controls to operate regularly. Avoid defrosting more often than necessary and try not to defrost during peak energy usage periods. Refrigerators that you have to defrost manually are generally more efficient than automatic defrost models, but only if they are properly maintained. Freezers should be defrosted if the ice build-up is thicker than 0.5cm. - Use the correct temperature setting. Keeping foods colder
- During winter, freezer space often goes unused. Your refrigerator, however, continues to use energy. - Check the door gasket occasionally to be sure the seal isn’t
- Refrigerators should not be located near the stoves, dishwashers, heat vents or exposed to direct sunlight. Check that the air flow around your refrigerator is not obstructed.
The freezer should be between -17°C and -20°C. - Clean the condenser coils.
Relative Cost
Microwave
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it should be turned on during the summer and off during
Electric, self-cleaning
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the winter.
Electric, self-cleaning, convection
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Note: Costs are in terms of how much electricity an oven would use for a task relative to a microwave oven. For instance, if it costs 50c to cook an item in a microwave oven, it would cost approximately R2.40 in a standard electric oven.
- Never run frost-free refrigerators with freezer compartments in unheated areas with air temperature below 16°C. - The most efficient refrigerators are 450l to 550l, with a freezer on the bottom or the top rather than the side. Foregoing features like auto defrost, ice makers and heaters energy costs, but save you money on the purchase price
Temperature settings usually need to be reduced in winter.
Cooking Method
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shelf life. Adjust temperature settings for different seasons.
In the morning, the temperature should read 1°C – 4°C.
Relative Cost of Operating Ovens
Electric, standard
- If your refrigerator has an energy saving (anti-sweat) switch,
to control condensation can not only save up to 60% on
a jar of water and leaving it in the refrigerator overnight.
Choose an efficient oven. The efficiency of ovens varies widely with how they’re operated but there are general comparisons that can be made.The following table provides a comparison of the efficiency and relative operating cost of the different types.
broken by debris or caked up food.
than necessary costs more and rarely pays off in extended Check refrigerator settings by placing a thermometer in
Saving energy with your ovens
as well.
Maximise your use of microwave ovens They are the fastest, most efficient and cost the least to operate. They only use half to a third as much energy as conventional stoves, so try to use them whenever possible. Microwaves ovens save energy by only heating the food and not the surrounding air, like standard ovens. Clean the inside of your microwave oven to keep it operating efficiently.
when actual cooking is taking place without any preheating. Because of these advantages, Flashbake® ovens are increasingly being used in commercial kitchens to increase productivity.
Solar ovens Solar ovens are the most energy efficient cooking appliance, as they require no fuel of any kind, yet they reach temperatures up to 400°C. Even though these ovens are super-efficient they
Convection ovens
are not yet practical for commercial use.
Convection ovens use fans to circulate hot air around food as
Hybrid solar ovens
is one of the largest single contributions you can make
it cooks. The motion of the air increases the rate at which heat
to lowering your electric bills and to conserving energy
These have the benefits of a solar oven with the added
is transferred to the food. As a result, convection ovens cook
and resources.
convenience of an energy efficient electric backup for when the
more quickly at lower temperatures to achieve the same results
sun isn’t out. In ‘electric mode’, these hybrid units use 75% less
as conventional ovens - according to manufacturers, convection
energy than the conventional electric range of ovens.
- One large refrigerator is cheaper and more efficient to run than two smaller ones. Getting rid of an old refrigerator
ovens cook in 10% less time at a 14°C lower temperature. Due to the increased circulation of heat, convection ovens can also be loaded more fully than conventional ovens, leading to productivity improvements.
Flashbake® ovens Flashbake® ovens use a combination of intense visible light from halogen bulbs and infrared energy to cook food. This combination produces the browning effect of conventional ovens at almost twice the speed. Unlike conventional ovens, it isn’t necessary to leave these ovens on during non-cooking times to maintain the oven’s temperature. They only operate 7
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General energy saving in the kitchen
Saving energy with stove tops Energy efficiency using stove tops
Lighting - Turn off lights in areas where daylight is sufficient. Keep lighting fixtures and lamps clean.
Opportunities for increasing energy efficiency while using a stove top cooker include:
on an electric element will use about two thirds of the energy
- Incandescent lamps can be replaced with Compact Fluorescent Lamps (CFL) that can significantly reduce lighting costs and last
as a warped piece of cookware.
up to eight times longer. The payback period for a CFL is 10 months and its lifespan will exceed 3 years or 6000 hours!
Using pressure cookers
Fitting equipment to the correct burner
- Retrofit incandescent or mercury vapour parking lot lights with more energy-efficient lighting, such as High Pressure
For a given hob setting, pressure cookers cook food at higher
Pots and pans should be one inch larger in diameter than the
temperatures because the pressure they produce raises the
burner they are resting on. Pots and pans correctly matched
- T-12 fluorescent lamps and magnetic ballasts can be replaced with T-8 or T-5 lamps with electronic ballasts.
boiling point. The higher temperature allows the food
to burners can save energy rands by reducing cooking times
- Utilise photocells or Light Emitting Diodes (LED) for all-night outdoor or decorative lighting.
to be cooked faster, reducing energy costs by about two
since more of the burner’s heat gets absorbed by the cookware
thirds. Compared to a regular pan, a pressure cooker may use
and the food.
only 25% of the energy, to cook the same meal.
Sodium Vapour (HPSV) or metal halide.
See the table below which shows the efficiency of lighting with CFL.
Using lids Lids help to keep heat inside cooking equipment. It is estimated that cooking with a lid increases efficiency by 8% – 14%. Using lids can help you to make big savings with no additional investments.
Choosing an efficient stove top The table below provides energy efficiency and the relative
Incandescent
CFL
Life Expectancy
1 000u
6 000u
Cost per unit
R3.00
R20
Consumption in W
60W
14W
Electricity cost per month (tariff 0.55)
R4.95
R 1.155
Electricity savings per month
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6.9kWh
If you’re in the market for a new stove top, take a minute to
Electricity cost savings per month
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R3.80
consider the energy impact of your decision. Remember that
Electricity cost savings over a year
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R45.54
cost information for the most commonly available stove tops.
there will be an energy cost that lasts for the life of the stove.
Using flat-bottomed cookware on electric elements and closed-top cook tops The contact between cookware and the cook top or electric element is important for efficiency. Flat-bottomed cookware
Stove Top Type
Efficiency(%)
Energy Factor (%)
81
81
74
74
40
19
40
40
Consider induction stove tops Induction stove tops have many advantages over conventional stove tops including efficiency, control and safety. They heat the pan directly by creating a strong magnetic field, which in turn induces a current in any ferrous (magnetic) pan. The current causes the pan to heat and cook the food. The stove top stays relatively cool and it is nearly impossible to start a fire by leaving the burner on. No special cookware is required - any magnetic pan will work, although there are pots and pans designed specifically for use with induction stove tops.
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General energy saving in the kitchen Other energy saving ideas for the kitchen Use low heat
Install an aerator on the kitchen tap Reducing the water flow saves hot water and the flow change isn’t noticeable.
Saving energy with your fryer and broiler Saving energy with the fryer
Saving energy with the broiler
Opportunities for improving the energy efficiency of fryers include:
Opportunities for more energy efficient broiler use include:
Whether cooking on the stove top or in the oven, using the
Minimising preheating times
lowest temperature setting possible can save energy.
Follow the manufacturer’s recommendations for preheat times.
Cooking on a low heat also preserves nutrients, retards meat
Excessive preheating times only wastes energy.
shrinkage and preserves colour.
Keep them full
Keep stove tops, ovens, fryers, broilers and griddles clean
Load broilers to capacity whenever possible to use all of the available surface area. If it’s not possible to fully load the broiler,
If your stove top has reflective pans below the burners, you’ll
heat only as many sections as you need.
save by keeping them clean and shiny. The more reflective they are, the more heat will be re-directed to cookware. If you have
Use infrared broilers
a stove top with concealed burners, keeping the stove top clean
They require no preheat time. Since they respond so quickly,
will help transfer heat to the cookware. The same is true
it is even possible to turn them off between loads.
of ovens, fryers, broilers and griddles – the more accumulated debris there is, the harder it is for the appliance to heat the food, and the more energy will be used to do the job.
Use the appropriately sized appliance for the task at hand In general, smaller appliances use less energy than their larger counterparts. For instance, if you can use a smaller oven for the task at hand, doing so will save energy. Electric frying pans, woks and slow cookers are considerably more efficient than stove top burners.
Turn off electric burners several minutes before the allotted cooking time Conventional electric resistance heating elements stay hot for a while after they are turned off – usually enough to finish the cooking task without using more electricity.
Limiting fryer preheating times Preheat fryers no longer than the manufacturer’s recommendation, usually 7-15 minutes. Letting a fryer preheat longer than needed increases energy costs while a high initial preheat setting will not heat the fryer any faster, but it may overheat the fryer and waste energy.
Removing sediment Sediment should be filtered from the fryer often. As sediment accumulates, the energy efficiency of the fryer is greatly reduced.
Cleaning the heating element Accumulated debris on the element makes it more difficult to transfer heat from the fryer to the oil which drives up energy costs.
Checking the cooking temperatures Use a reliable thermometer to check the temperature of the fryer. If the temperature is significantly different from the setting, fixing the thermostat could save you energy and improve the quality of the food.
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