ARCHIVED - Step 4: invest in Energy Efficiency Retrofits

Cherry Picking Versus Multiple Measures

If leasing, you may be hesitant to conduct retrofits – especially those with longer payback periods. If you own the building, retrofits will not only save energy dollars, but they will also increase its value if you decide to sell your property. When conducting retrofits, there is a temptation to tackle each measure – one at a time favouring those with the shortest paybacks. in energy management circles, this practice is known as “cherry picking”. Once all short-payback retrofits have been completed, you are left facing a number of long-payback measures that will become increasingly difficult to justify. The wise approach is to bundle multiple short- and long-payback measures. You will be more likely to complete all retrofits sooner, and you will be able to subsidize long-payback projects with savings from fast-recouping capital improvements. See “Step 5. Calculate Your Savings” for definitions of simple and incremental paybacks.

Capital investments in equipment are almost sure to save you energy and money. in fact, energy retrofits can reduce your costs and consumption by an average of 20 percent or more. in addition to cost savings, these measures can add to your facility's aesthetics and increase comfort levels so customers are encouraged to stay longer, spend more and return again.

This section highlights some possible investments you may want to consider as you work to improve the energy efficiency of your retail store or shopping centre. At the beginning of each section, you will find a short description on the relevancy of the measure to you – depending on whether you have a store, supermarket or mall. Later in the guide, you will find a number of low- and no-cost “Energy Tips” for saving energy and money.

Table 3. Energy Retrofits: Typical Savings and Payback

System	Estimated Energy Savings* (GJ/m2)	Approximate Payback* (years)
Lighting and Electrical	0.06	4
Food Refrigeration	0.16	4
Motors	0.02	5
HVAC	0.20	6
Domestic Water	0.09	4
Controls	0.07	5
Building Envelope	0.03	8

* Figures are estimates from projects that have received energy-retrofit financial incentives through the EII.

 

Lighting

Stores – in a retail business, lighting is crucial to your store's ambience, customer navigation, product presentation and sales strategy. It attracts the customer to your store, highlights the product and helps complete the sale. Managers of retail stores generally have little control of lighting measures, other than in back-of-store areas, such as employee lounges or storerooms. Since lighting can be such a critical factor in sales, head office or the franchiser typically set exact lighting specifications based on the advice of lighting consultants. If you do have control over your lighting, remember that natural lighting is important. Contrasting or non-uniform light levels are visually appealing and practical – jewellery displays should be well lit, while lighting around television displays should be dimmer. Prevent direct or indirect glare -off glass shelves or mirrors – into the eyes of your customer. With new lighting technologies, you can use less energy without reducing the quality and quantity of light.

Supermarkets – Supermarkets are usually built or renovated to match a model store designed by experts. As the case with retail stores, managers of supermarket stores do not choose lighting, but may have more control over employee break rooms and other back-of-store areas.

Malls – Managers of shopping centres may not have strict restrictions from owners, but they are generally responsible for lighting only in common areas and exteriors. With that said, of all your direct energy costs, lighting presents a key area for savings. Since lighting is often spread out over a large area, centrally controlled systems – such as those described in the “Control Systems” section – are crucial to overall lighting management.

The OEE offers a range of documents that provide additional or more complex technical information on specific energy efficiency measures:

• Buildings and industry Publications and Products Catalogue
• Technical Fact Sheets
• Energy Management Series
• CADDET Analyses Series Reports (international)

You can order these and other documents through the EII's Publications Web site at oee.nrcan.gc.ca/eii/ publications.cfm or the OEE Energy Publications Web site at oee.nrcan.gc.ca/publications.

Designed for Savings and Service

• Exterior lighting must create a positive impression not only to attract people to your store or mall, but also to provide a sense of comfort and security between the parking area and entrance. Use photocells to ensure that outside lights operate only at night. Metal halide and other high-intensity discharge (HID) lamps last longer than either incandescent or mercury-vapour sources. They also offer energy savings from 75 to 90 percent and provide the same safe and inviting illumination.

• Interiors are generally lit with incandescent tungsten bulbs or fluorescent systems with magnetic ballasts. T8 or T5 fluorescent bulbs are as much as 30 percent more efficient. If an area has more light than necessary, consider switching to a low-ballast-factor (LBF) fixture that uses standard bulbs with less light and less energy consumption. Traditional incandescent bulbs generate heat and, as a result, increase cooling loads that waste even more energy. Compact fluorescents can often use the same fixtures, giving the same degree of light while using up to 75 percent less electricity. The colour-rendering abilities of fluorescent and compact fluorescent bulbs improved significantly in the late 1990s. Moreover, fluorescents or metal halides can be used for ambient or wall lighting. You can save a lot by reducing the number of lights, such as switching from four- to two-tube fluorescent fixtures, and, with new lighting technologies, still maintain acceptable lighting levels.
   
• Display lighting is important for drawing attention to showcase items and enhancing aesthetics, but many retailers use inefficient incandescent spotlights. Halogen lighting provides a more controlled beam and can be brighter than traditional incandescent bulbs, while maintaining excellent colour rendition and saving you up to 50 percent on energy costs. Decorative halogen lights offer a similar quality of light and can be dimmed like incandescent bulbs, and the brighter white can add sparkle and a higher sense of quality – especially to glassware, crystal, china and chandeliers. Use light sensors in window displays to offer enough lighting in the day and night.
   
• Washrooms often use incandescent lamps that waste energy or cool-white fluorescent lamps that make customers' skin tones appear washed out. Higher-quality fluorescent lamps reflect true flesh tones and bring out the colours in the décor while saving energy.
   
• Exit signs offer the opportunity for significant savings. Light-emitting diode (LED), electroluminescent, photoluminescent and light-rope exit signs have approximate payback periods of less than two years.
   

• Kitchens must be well lit to ensure efficient food preparation, minimize the risk of accidents and encourage thorough housekeeping. T12 fluorescents are currently the most common kitchen-lighting fixtures, but switching to T5s or T8s with electronic ballasts will save you energy and provide short paybacks. Consider also installing timed switches or low-temperature occupancy sensors in walk-in refrigerators and freezers.
   
• Back-of-store areas such as employee break rooms, storage areas and office space – rarely require light 24 hours a day. Occupancy sensors ensure lights are on only when someone is in a room. With many models priced from $50 to $100, these sensors can reduce energy consumption 15 to 80 percent, depending on usage. Replacing fixtures with T5 or T8 compact fluorescents will save even more energy.

Table 4. Energy-Efficient Lighting

Old System	Old Watts*	New System	New Watts*	Annual Open Hours
Incandescent	100	26-W compact fluorescent	29	4380
Incandescent exit signs	50	LED exit signs	4	8760
Two T12 34-W fluorescents with magnetic ballasts	81	Two T8 32-W fluorescents with LBF electronic ballasts	51	4380
400-W mercury- vapour security lighting	424	250-W metal halide	285	4380

Table 4. Energy-Efficient Lighting (Continue)

Savings (per unit)	Cost (per unit)	Approximate Savings (per unit)	Approximate Payback
311 kWh 1.1 GJ	$25	$21	1.2 years
403 kWh 1.5 GJ	$45	$28	1.6 years
131 kWh 0.5 GJ (for the pair)	$70 (for the pair)	$9	7.8 years
609 kWh 2.2 GJ	$250	$43	5.4 years
* Ballast energy will increase power draw, so actual wattage – both old and new – may be higher than indicated on the bulb or system. Assumes electricity costs of $0.07/kWh, including demand and service charges. Prices are estimated, so actual results may vary. There are 8760 hours in one year. This table does not reflect maintenance savings resulting from longer lamp lives. Refer to "Step 5: Calculate Your Savings" ” to learn how to determine paybacks.

The Vocabulary of Lighting

Shape and size codes determine the many types and styles of bulbs on the market. For example, a 60A19 refers to a 60-watt arbitrary – or standard-shaped – incandescent bulb with a maximum diameter of 23/8 in. (each unit equals 1/8 in., so 19 x 1/8 = 2 3/8 in.). An F32T8/841-48 is a 48-in..-long 32-watt tubular fluorescent bulb, 1 in. in diameter (8 x 1/8 in.), with a colour rendering index of 80 and a 4100 K colour temperature.

Light output (or luminous flux), measured in lumens, is the quantity of light per second. For example, a 100-W incandescent produces about 1750 lumens compared with a 25-W fluorescent at about 1550 lumens.

Lux is the amount of light that strikes a surface, such as a wall or floor, and is equivalent to lumens per square metre or 0.093 foot candles. in retail, lighting levels vary, from 150 lux for background lighting to 1000 lux for display lighting in big-box stores. Storeroom levels are typically low at 100 to 300 lux. These recommended lighting levels are rising to account for the aging eyes of the average Canadian – increasing the need for more energy-efficient lighting.

Efficacy measures the conversion of electrical energy into light in lumens per watt (lm/W). The efficacy of an incandescent bulb is only 10 to 20 lm/W compared with a compact fluorescent at 50 to 65 lm/W, T8 liner lamps at 80 to 100 lm/W, metal halide at 75 to 120 lm/W and a low-pressure sodium light at 120 to 190 lm/W.

Colour rendering index (CRI) is an objective measurement of how well colours can be seen. For example, incandescents have a rating of 97; fluorescents, 52 to 94; and metal halides, 65. As a rule of thumb, use bulbs with a CRI of at least 80 for merchandising. Fluorescent and other bulbs can come in a range of colours – from white to pink to yellow – and for aesthetics, you should take care not to mix bulb colours in one area.

Lamp life is important when choosing your lights since costs are incurred when you buy the bulbs and each time your maintenance staff must change them. incandescent bulbs have the shortest life at only 2000 hours. Fluorescents, metal halides and other energy-efficient bulbs often last between 10 000 and 30 000 hours. Some bulbs will dim with age, so read the specifications to learn the characteristics before purchasing.

Ballasts are electrical devices that limit the current and control the voltage in fluorescent lamps. Magnetic ballasts are an older technology that often hum and flicker. If produced before 1979, these ballasts may contain harmful polychlorinated biphenyls (PCBs). Electronic ballast systems are often about 30 percent more efficient, eliminate flicker and noise and – unlike magnetic ballasts – can be dimmed for softer illumination and even greater energy savings.

Reflectors have mirror-like or reflective white surfaces that focus light and increase lumen output. By using reflectors, you can generally reduce the total wattage and number of lamps by 25 percent with no decrease in overall light levels.

Dimming controls are useful for providing supplemental illumination in areas where natural light is available during the day. Dimmers also help create an intimate atmosphere or control lighting levels for presentations. Dimming controls can extend lamp life and reduce lighting costs by 35 to 70 percent, with an approximate payback of 3.0 to 7.5 years. For more information, see the “Control Systems” section.

Daylighting refers to the use of natural light in interior and perimeter areas. Windows, skylights and translucent daylighting panels (described in the “Building Envelope” section) can reduce your daytime lighting requirements by over 50 percent. Research suggests that the presence of daylight also helps increase staff productivity and customer-satisfaction levels and sales. Use bright interior colours to maximize the daylighting effect.

These Web sites contain useful lighting information for stores, supermarkets and malls and include energy efficiency recommendations for different types of rooms and uses:

Alliance to Save Energy at www.ase.org/section/topic/lights/

Berkeley Labs Virtual Lighting Simulator at gaia.lbl.gov/vls/

GE Lighting at www.gelighting.com/na/business_lighting/

Lighting Research Centre at lighting.lrc.rpi.edu

Philips' bulbs.com at www.bulbs.com/lightingguide/

 

Food Refrigeration

Stores – Food refrigeration is not a factor for most retailers, but there are exceptions. A growing number of big-box stores are selling perishable and frozen food in addition to non-food dry goods, and many department stores contain restaurants with walk-in coolers or freezers. Florists and furriers also have requirements for cooled sections, but this is normally handled through air-conditioning units described in the “Heating, Ventilating and Air Conditioning” section.

Vocabulary of Refrigeration

Compressors have a refrigerant pump and motor resistance and are the main cooling components of any refrigeration system. They can be found locally within a cooler or freezer or centrally in a plant room.

Evaporators are the cold part of a fridge circuit and remove heat from a display cabinet.

Condensers are the warm part of a circuit and emit heat into the atmosphere. These units usually have a fan to help with heat loss and may be combined with a compressor in a "condensing unit."

Refrigerant is the fluid that is pumped through a system – evaporating to remove heat and condensing to release heat.

Chlorofluorocarbons (CFCs) are refrigerants that were internationally banned by the Montréal Protocol (1987) since they are harmful to the ozone layer. If you have not yet phased out older units, this provides another reason to replace older coolers and freezers.

Supermarkets – in a food store, refrigeration can account for over 50 percent of your energy consumption, so it should be one of your main targets for energy measures. As with lighting, head office usually makes decisions on refrigeration based on expert advice. As referenced in the “Heating, Ventilating and Air Conditioning” section, open-air coolers present special challenges since they cool the air while, at the same time, producing heat.

Malls – Tenants are usually the responsible for refrigeration but, since costs can be high, the individual metering of stores with food refrigeration is important.

Cool and Efficient

• Doors should be installed on open freezers and refrigerators. It is cost effective to replace old refrigeration units with energy-efficient new ones.
   
• Night blinds should be installed on all open cooling cabinets, if none exist already. For displays with goods that are accessed less often, consider day covers or plastic strip curtains.
   
• Heavy plastic curtains outside your walk-in cooler or freezer keep the cold air in and the warm air out.
   
• Energy-efficient central compressors, properly sized to match the load, can be one of your most important investments since compressors are one of the largest energy users.
   
• Compressor and evaporator fan controllers for walk-in coolers and freezers, such as the variable speed drives mentioned in the “Motors and Drives” and “Heating, Ventilating and Air Conditioning” sections, can cut the voltage to the motor and slow down the fan when full air flow is not needed. They are most useful in units that run between 22° to 4°C (28° to 40°F), with evaporator fans that run at full speed all the time. Different models include basic units that sense when the refrigerant has ceased flowing through the evaporator coil, mid-range units that monitor data over time and activate warning lights and top-end units that have a modem for remote or full-time monitoring. With investments as low as $100 per unit, savings can vary from 10 to 60 percent of overall refrigeration energy consumption and have paybacks as low as one year.
   
• Remote condensers allow for the rejection of heat to the building's exterior, instead of into the retail space when the air requires cooling.
   
• Demand-defrost controls initiate defrost cycles only when needed, instead of using automatic timers.
   
• Dewpoint controls on display cases prevent the buildup of fog on glass surfaces and the buildup of moisture on metal surfaces.
   
• Larger heat exchangers are more efficient than multiple, smaller units so when renovating, try to group cabinets together to better facilitate heat removal or recovery.
   
• Fibre optic lighting piped into cabinets minimizes heat input from traditional lighting.
   
• Lighting occupancy sensors for walk-in coolers or freezers will ensure that lights are only on when needed and will make it easier for employees to carry food in and out.
   
• Insulation in coolers and freezers should be inspected and upgraded regularly.

A calculator to help determine if you should invest in walk-in cooler controllers is provided by the Los Angeles Department of Water and Power at www.ladwp.com/ladwp/cms/ladwp001511.jsp.

 

Motors and Drives

Stores, Supermarkets and Malls – Motors are used to run HVAC systems, escalators, elevators, hardware-store tools (key cutters, saws) and other equipment, and can account for up to 50 percent of your facility's overall energy use. Over a typical 10-year operating life, a motor can consume electricity valued at 50 times the original cost of the equipment. Using this calculation, a $1,000 motor running continuously for a decade could cost you up to $50,000 in electricity. Store managers can sometimes have more decision-making power over replacing and upgrading motors than with standardized measures, such as those for lighting and refrigeration.

The Vocabulary of Motors

Motors are classified as AC (alternating current from outlets), DC (direct current, usually from a battery) or universal (operating as either AC or DC). A motor's mechanical power is measured in either kilowatts (kW) or horsepower (hp) (1 hp = 0.746 kW). The two factors that determine power are torque (measured in newton metres or pound feet) and speed (measured in revolutions per minute [rpm]). The slower a motor operates, the more torque it must produce to deliver the same amount of power. A motor's efficiency is a measure of the energy it delivers (output) relative to the energy it uses (input).

Assess Your Needs for Optimum Efficiency

• Energy-efficient motors are good investments. Even if they yield only 2 to 8 percent in energy savings, these motors generally achieve incremental paybacks in 2.5 to 5.0 years compared with buying less-efficient replacement motors.
   
• Adjustable-speed drives (ASDs) – sometimes referred to as variable-speed drives (VSDs) and variable-frequency drives (VFDs) – regulate motor speeds according to the amount of work required. Reducing motor speed by 10 percent can cut power consumption by 27 percent, and a 20 percent speed reduction can cut consumption by 49 percent. These drives are particularly useful when combined with high-efficiency motors since they tend to run faster than conventional motors. An added benefit is their ability to reduce noise – an important consideration in the retail industry. These drives can save on your facility's total energy consumption, but tend to be expensive, with approximate paybacks between two and eight years.
   
• Power-factor correction capacitors are devices that store electrical charges and reduce consumption of reactive power that motors need to generate magnetic fields. These are important only if you have demand charges on your electricity bills (see “How to Read Your Energy Bill” in Step 1).
   
• Energy-efficient drive belts have teeth or longitudinal grooves that improve grip, reduce slippage and are only slightly more expensive than standard V-belts. Ensure that drive-belt inspections are performed every few months as part of regular maintenance, and replace the belts when they wear out.
   
• Choose the right motor for the job. Oversizing is the inefficient practice of employing a larger motor than required for a task. This is a particular concern if the motor is loaded under 50 percent.

 

Heating, Ventilating and Air Conditioning

HVAC accounts for some of your highest energy expenses, but these systems are also critical to employee productivity and to the comfort and satisfaction of your customers and tenants. If your facility is too cold or too hot, you can expect complaints. HVAC systems also contribute to your facility's air quality, and fresh air is particularly important in enclosed or high-odour areas. For optimum efficiency, ensure that the functions of each HVAC component complements the others – especially when ventilation systems help distribute warm and cold air.

There are many types of HVAC systems, but the self-contained, packaged systems that combine heating, ventilating and air conditioning are most common in retail. Rooftop HVAC units (RTUs) are often used in single-zone, single-storey buildings. Fan coil units are a component of central systems often used in malls and larger department stores. in these systems, air is blown over coils that have been heated by boilers or cooled by chillers in a central plant. You can also realize savings with the efficient use of cooling towers, air-to-air heat exchangers, air-handling units (AHUs), heat pumps and other HVAC components.

Stores – For smaller retailers, the landlord generally supplies HVAC, although many stores have smaller supplemental systems in addition to packaged units. HVAC systems not only keep your customers comfortable, they also compensate for heat-producing lighting and for large exterior windows that can cause heat gain in summer and heat loss in winter. in department stores, HVAC requirements may change throughout a single facility, depending on the concentration of people, lighting density and use of space. For example, if your store contains a restaurant, a hair salon, a television/stereo section, a lighting section, a paint shop or washrooms, these areas have special needs. And florists and furriers must maintain cold rooms with a dedicated chiller unit. (Many of the measures listed in this section may not apply to stores that use packaged systems.)

Supermarkets – HVAC holds special challenges for supermarkets. Open refrigerated display cases cool the air, but compressors have to work harder and can give off extra heat if the store is too warm. Other equipment and in-store bakeries can generate unwelcome heat in the summer. At any one time, most staff and customers are concentrated at the checkout area at the front of the store, requiring increased ventilation. The front area also features large windows and exterior exits – features contributing to heat loss in winter and heat gain in summer. (Many of the measures listed in this section may not apply to food stores that use packaged units.)

Malls – Your system regulates HVAC in common areas and, in most cases, for your tenants. Different tenants have different needs, and you need to meet capacity under varying conditions. High ceilings in common areas, heated entrances and smells associated with food courts require special ventilation.

Common HVAC Measures

• Pick the right system when replacing your HVAC unit, usually at the end of its life cycle. in addition to energy efficiency, consider the size, weight, maintenance costs and noise levels.
   
• Outdoor air economizers should be included with air-handling units, so outdoor air can be used for free cooling during spring and fall or on cool summer nights when the humidity level is not too high.
   
• Smart thermostats provide preset limits for heating and cooling – overriding unnecessarily high or low settings by staff. These thermostats also feature digital controls and readouts that ensure greater accuracy than the sliding levers on traditional units.
   
• Night temperature setbacks involve the installation of an automatic thermostat that controls the temperature when the store is closed.
   
• Scheduling or cycling is the practice of shutting down your HVAC equipment for short periods throughout the day. For example, shutting down fans and other systems for three minutes an hour represents 5 percent of your consumption, but may not be noticed by customers or tenants. The trick is to reduce consumption without a perceptible change in temperature. If the temperature changes, your system will have to work harder to return to desirable temperature and humidity levels.
   
• Heat recovery ventilators (HRVs) and energy recovery ventilators (ERVs) have balanced exhaust and supply fans that meet all ventilation needs without creating drafts and air-pressure imbalances. HRVs can feature efficiencies as high as 85 to 95 percent, with payback in roughly 3.5 years. Consider these units whenever air is continuously exhausted and make-up or ventilation air is required.
   
• Variable-speed drives (VSDs), described in the “Motors and Drives” section, can be used with variable-air-volume (VAV) systems to adjust fan speeds according to operating requirements at different times of the day. in kitchens, for example, fans can be linked to burners to reduce energy consumption during off-peak cooking periods. Be careful, however, not to cut exhaust to the point that kitchen odours permeate other areas of your facility.
   
• Zone isolation and demand control ventilation (DCV) reduce airflow when low carbon-dioxide levels indicate a room is not in use. Implementing these measures may involve the use of variable-frequency drives (see the “Motors and Drives” section) and shut-off dampers, as well as reductions in the amount of outside air used by your HVAC system. Energy is saved not only because air distribution is reduced, but also because less air must be heated or cooled.
   
• Removable and re-usable insulation for pipes, valves and fittings is made of non-combustible materials and can provide paybacks as short as four months. Traditional insulation is often not replaced once it has been removed or damaged during maintenance. This can lead to tremendous heat loss or gain, as well as condensation and safety hazards. Removable and re-usable insulation provides a solution by simplifying both maintenance access and thermal-barrier replacement.
   
• Heat pumps transfer heat from a lower-temperature source to a higher-temperature area. in the winter, they extract heat from the outside and transfer it to the interior; in the summer, they cool inside spaces by extracting heat from the inside and transferring it to the outside. High-efficiency units can operate 10 to 30 percent more efficiently. Depending on the heat source, a heat pump can produce two to three times the energy consumed. Geothermal or ground-source heat pumps (GSHPs) are particularly efficient in areas with cold winters, since ground temperature is usually warmer than outside air in winter and cooler than outside air in summer. This allows GSHPs to perform 45 to 70 percent more efficiently than conventional systems.
   
• Proper maintenance is critical to any system since it helps reduce operating costs, extend operating life and avoid costly repairs. This is especially true with cooling towers, which are subject to scale deposits, clogged nozzles, biological growth, poor airflow and poor pump performance. These factors can diminish performance and raise operating costs by 10 to 25 percent. For air-handling units, buying high-quality filters will reduce airborne dust and contaminants. in new boilers, proper maintenance can deliver savings of up to 20 percent.

The Vocabulary of HVAC

Btu/h, or British thermal units per hour, measure heat produced by boilers and cold produced by chillers. A single unit is the equivalent of 0.000295 kW or 0.000001055 GJ/h (one millionth of a GJ per hour).

Boiler hp (horsepower) measures boiler power and is equal to 33 520 Btu/h, 9.8 kW, 15.7 kg/h of steam or 0.0353636 GJ.

Boiler efficiency is calculated according to the formula: output energy divided by input energy multiplied by 100. Calculations are affected by such factors as thermal efficiency and fuel-to-steam efficiency.

Chiller efficiency measures power input per ton of cooling produced by larger chillers. A lower number indicates higher efficiency. The unit of measurement is kW/ton, in which ton is the amount of cooling produced when one imperial ton of ice melts. One ton equals 12 000 Btu/h or 3.516 thermal kW.

Energy efficiency ratio (EER) measures the performance of smaller chillers and rooftop units (as opposed to the kW/ton, which is used to measure the power of larger chillers in room air conditioners). EER is calculated by dividing the cooling capacity in Btu/h by a chiller's power input in watts. The higher the EER, the more efficient the unit. Standard heat-pump units often have EER values of 8.9, whereas higher-efficiency units may reach 10.

Coefficient of performance (COP) is energy output divided by energy input. The higher the COP, the more efficient the chiller or heat pump.

Seasonal energy efficiency ratio (SEER) applies to central rooftop air-conditioning units with cooling capacities of less than five tons. SEER is a seasonally adjusted rating based on representative residential loads.

Heating-Specific Measures

• High-efficiency condensing boilers will save you a great deal of energy when it is time to replace old boilers. These units can achieve seasonal efficiencies as high as 96 percent (compared with 75 percent for old boilers). incremental paybacks of two to six years are common compared with purchasing midrange replacement boilers, but initial costs can be twice as high. For example, the piping distribution and terminal-heating units may need to be redesigned for condensing boilers.
   
• Boiler flue gas economizers are heat exchangers that preheat water using boiler-stack and exhaust gases. With installed costs of about $35,000, economizers deliver a 5 to 10 percent increase in efficiency and, in large facilities, paybacks of four to 10 years.
   
• Air preheaters use hot stack gas to preheat fuel and air before combustion. These units cost about $15,000 and have payback periods from 2.5 to 3.5 years.
   
• Boiler combustion and oxygen-trim systems minimize energy loss by reducing the amount of excess air or fuel in a boiler stack. An automated oxygen-trim control system ensures that the proper fuel-to-air mixture is maintained. With a typical cost of $10,000 for a 300-hp boiler, these units deliver energy reductions of 1 to 5 percent and paybacks of approximately five years.
   
• Boiler blowdown heat recovery uses a heat exchanger to extract thermal energy from hot water that is continuously drained from a boiler. Prices range from $10,000 to $35,000, depending on the amount of steam supplied. Paybacks are about 6.5 years.
   
• Continuous boiler blowdown monitoring and control systems reduce the amount of hot water continuously drained from boilers. These systems typically cost $2,500 to $6,000, with approximate paybacks of five years.
   
• Automatic vent dampers for boilers prevent residual heat from being drawn up the warm stacks, reduce the amount of air that passes through furnaces or boiler-heat exchangers and improve comfort conditions during the winter by helping retain humidity in a building.

Cooling-Specific Measures

• Energy-efficient chillers have better controls, condensers and compressors than regular units. Their costs, however, may not always yield reasonable paybacks and may not make up for inefficiencies in other parts of air-conditioning systems, such as pumps, cooling towers and controls.
   
• Refrigerants themselves can save you energy. For example, chillers that use an HCFC-123 refrigerant have the highest energy efficiencies today, at 0.49 kW per ton.
   
• Thermal energy storage (TES) enables you to store cool water for later use as an air coolant. This function is particularly valuable for use at peak demand times during summer days. Approximate payback is 10 years.

 

Water

Stores, Supermarkets and Malls - Domestic hot water (DHW) – for washrooms, kitchen sinks and dishwashers – is supplied either by boilers within the HVAC system of larger facilities or, more commonly, through point-of-use water heaters. Domestic cold water is also an important consideration in larger stores and shopping malls, since energy is often required to pump water for toilets/urinals, fountains, faucets, landscaping, water-cooled air conditioners, cooling towers and humidification. Many drinking-water purification processes also consume energy.

Water-Saving Ideas

• Pick the right system for your facility. A unit that is too small may leave you without hot water, and too large a unit will consume more energy than necessary.
   
• Water heater timers ensure the heaters operate only during opening hours. Insulating jackets for water heaters are also an inexpensive investment with short paybacks.
   
• Low-flow and/or low-temperature commercial dishwashers save 35 to 60 percent on water and water-heating energy.
   
• Low-flow toilets, waterless urinals, urinal sensors and other water management measures can reduce cold-water use by over 20 percent. Talk to a water management consultant or your water utility for more information.

 

Control Systems

Stores, Supermarkets and Malls – Energy management control systems enable facility managers to improve energy efficiency by automating lighting, HVAC and other equipment. Simple controls can be used within any size of retail establishment, but the emphasis should be on simplicity so your retail staff can use them. More complex systems are important in shopping malls or larger stores with maintenance staff.

Help Manage Your Facility's Energy Use

• Simple control systems include time clocks, programmable electronic thermostats, programmable time controls, photocells and occupancy sensors. Occupancy sensors, which recognize the presence of people either through temperature change or motion, provide energy savings of 15 to 80 percent in rest rooms, small offices, storage or warehouse areas, staff rooms and other areas. Paybacks on most sensors are about five years. Although motion sensors mounted at light switches are the least expensive, they suit only small, open areas where occupants are constantly within range – not in large rooms or washrooms with stalls. The data network used by an electronic point-of-sale system can sometimes be used by the control system to share information within your facility and with head office. Carbon-dioxide sensors adjust ventilation depending on the number of people in a room.
   
• Energy management systems (EMS) are computerized systems that enable you to program various functions from a central point in your facility and provide early detection of operational problems. Some systems feature scheduling and monitoring functions that control temperatures and equipment in different zones – including fire or theft alarm systems. Many models can turn off equipment or activate backup generators at peak demand times. Some systems can be controlled centrally – enabling the activation of lighting and HVAC when stores open – while others are based on key-card access or occupancy sensors that manage lighting and HVAC based on room occupancy. A typical system for a shopping mall can cost $100,000 or less, with payback in as little as four years.
   
• Individual metering can ensure that you are paying only for your energy use – not your neighbour's -and that you see direct savings from your energy efficiency measures. Submetering within a large department store can help track your exact energy use.

 

Building Envelope

Stores, Supermarkets and Malls –The building's exterior is usually the landlord's responsibility. Many smaller retailers, if located in a mall or multi-use building, may have only an employee entrance or shipping door facing the exterior; some do not have exterior walls at all. Although a department store may have multiple customer entrances, even big-box stores and supermarkets generally have only one façade with windows. Most of the following heat-loss prevention measures apply to shopping malls and large chains. Better-quality windows, doors and insulation will help keep your utility costs down and also help reduce street noise – an important factor in the retail industry. Building-envelope improvements are generally more cost-effective when conducted as part of new construction or major retrofits.

Windows

• Various window options improve on the relative energy inefficiency of single-pane standard glazing. These include double- and triple-pane glazing, tinted glazing, reflective glazing, spectrally selective glazing and insulated glazing with inert gas between the layers. Wood and vinyl frames are more energy efficient than aluminum. Storm-window systems reduce heat loss in winter.
   
• A more cost-effective option than new windows is the installation of solar glazing or reflective film inside existing windows. Energy savings can be as high as 25 percent, with approximate paybacks in less than three years.
   
• Daylighting panels are translucent units that diffuse the light throughout the space and reduce glare, with higher R-values than conventional windows.
   
• Other window coverings such as shutters, shades and draperies provide insulation benefits, especially in summer when they reduce the amount of sunlight – and heat – entering rooms.

The Vocabulary of Building Envelopes

R-values measure the resistance to heat flow that occurs due to temperature differences between the interior and exterior (window and wall) of an envelope. The higher the R-value, the better the insulating properties.

U-values are the inverse of R-values (U = 1/R). in other words, they measure the amount of heat that will move through material rather than resistance to the movement.

Window performance is measured by shading coefficient (SC), solar heat-gain coefficient (SHGC), visible transmittance (T_vis), luminous efficacy (K_e) and R- or U-values.

Doors

• When replacing exterior doors, choose well-insulated, energy-efficient models.
   
• Revolving doors are the best choice for keeping wind and weather out of lobbies. Check these doors periodically to ensure there are no leaks along their edges or bottoms.
   
• High-quality weatherstripping that is durable and long lasting will help combat unwanted drafts.
   
• Install plastic secondary-door curtains inside delivery doors and bays.

Insulation

• Energy-efficient insulation types include fibre (usually available in loose-fill and batts) and foam (usually available in rigid sheets and sprays). Exterior reflective materials are also available, but offer poor insulation value.
   
• Seal air leaks and cracks by using foams, caulking and weatherstripping. Stuff fibreglass or glazier's foam backer rod insulation into areas too large to be caulked.
   
• Wall- and roof-insulation upgrades are best undertaken as part of larger renovation projects. Upgrades to insulation in basements and top-floor ceiling crawl spaces can be done anytime.
   
• If wet insulation is detected, replace it immediately once the source of the moisture has been identified and repaired.

Other Building-Envelope Measures

• Paint the exterior of your facility a light colour, if possible. This can help reflect summer heat, ease cooling loads and reduce energy consumption.
   
• Light-coloured roofing materials not only reduce cooling-energy consumption by 25 to 65 percent during the summer, they also extend roof life.
   
• A suspended ceiling reduces the area to be heated or cooled in big-box or other stores with high ceilings.
   
• “Living” or “green” roofs are becoming more common in Canada. Popular in Europe, these roofs are planted with grass and other vegetation. in addition to excellent insulating properties, this roof style could present multiple uses – and aesthetic appeal – in larger stores and malls.

 

Other Energy Efficiency Retrofits

Public Areas

• Vending-machine controls use passive infrared sensors to reduce energy consumption when traffic is low. These controls also monitor temperatures inside and outside machines to ensure quality products while consuming minimum energy. More importantly, the controls reduce the energy used by vending-machine lights by as much as 70 percent and save about $70 per year in low-traffic areas. Although soft-drink companies own most vending machines, you pay the power bills, so encourage your supplier to install only the latest and most efficient vending machines that contain energy controls.
   
• Energy-efficient computer monitors, including flat-panel LCDs, consume up to 90 percent less energy than models without power-management features such as sleep modes. Look for the ENERGY STAR^® label.
• Cogeneration or combined heat and power (CHP) systems produce two useful forms of energy – usually electricity and steam heat – from a single fuel source. Although conversion to such a system can be expensive, overall efficiencies of 85 percent are often achieved. CHP fuel costs are up to 35 percent lower than those for separate generation systems.
   
• Heat recovery systems capture and re-use heat that would otherwise be lost from refrigeration systems and other appliances, especially units that are water cooled. Grey-water heat recovery can be highly cost-effective in operations where kitchens and laundries account for significant water-heating energy use. Compressors also generate heat that can be captured for other uses.
   
• Compressed-air systems power many tools, pneumatic controls and fire-control equipment, but they can waste as much as 40 percent of their overall operating costs. Multiple-compressor control systems are more efficient than independently controlled systems. Repairing leaks and regularly replacing filters can achieve additional efficiencies.

Remember: Energy efficiency measures do not have to be expensive.

NRCan provides valuable information on energy-efficient equipment and appliances: EnerGuide at oee.nrcan.gc.ca/energuide and ENERGY STAR^® at oee.nrcan.gc.ca/energystar.

NRCan's Energy Resources Branch offers information on renewable energy at www2.nrcan.gc.ca/es/erb.

Berkeley Labs offers a number of links to energy-simulation software packages for buildings, including DOE-2 and EnergyPlus at gundog.lbl.gov.

Find simple explanations about the inner workings of equipment – such as air conditioners, electric motors, light bulbs and refrigerators – at How Stuff Works at http://www.howstuffworks.com/big.htm.