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Grocery stores get more energy saving tips from Power Line

Editor’s note: Grocery stores often represent large commercial accounts for small electric cooperatives. In this second of two features, the Western-sponsored energy information clearinghouse provides resources and advice to help those consumers control operating costs.

In the August Energy Services Bulletin, the Power Line offered a menu of low and no-cost measures to help grocery stores save money and electricity on refrigeration, the industry’s No. 1 energy consumer. Part II looks at advanced energy-efficient equipment and opportunities in other areas to reduce energy use.

Investment in technology increases refrigeration savings
Stores with the equipment budget to support major upgrades may want to look into additional energy-saving devices to boost refrigeration system efficiency. Ambient sub-cooling uses oversized condensers and an additional condenser to give more cooling to the refrigerant. It’s like adding a larger radiator or an oil-cooler to your car. Oversized condensers can save from 1 to 9 percent of cooling costs.

Mechanical sub-cooling adds a small pump to boost the pressure of the liquid in a refrigeration system. During the refrigeration cycle, the refrigerant changes from gas to liquid. In the liquid stage, the pump increases the pressure to improve system capacity and efficiency. Sometimes called liquid pressure amplifiers, these devices can cut systems energy use by as much as 25 percent under the right circumstances.

HySave Refrigeration holds the patent on mechanical sub-cooling and also supplies the equipment. The technology has great savings potential, but must be installed by a fully qualified refrigeration technician. Problems with leaking pumps have been reported, and the cost of replacing lost refrigerant can cancel out or even exceed energy savings.

Harnessing the byproduct of an electrical system to meet another energy need is the ultimate in efficiency. For every unit of cold a refrigeration system produces, it generates a greater unit of heat. A recovery unit added to the refrigeration system can capture heat as hot water or put it through a heat exchanger for heating in the winter. A 7.5-HP compressor is able to supply nearly 100 percent of the hot water needed in a medium-sized grocery store.

Better product displays add value to energy-efficient lighting
Lighting, the second largest energy-user in grocery stores, offers several opportunities not only to save energy but also to improve product presentation and customer satisfaction. For best results, consult a lighting professional when designing or upgrading store lighting.

Many technologies save energy and improve lighting quality. The general rule in all applications is that new lighting is more efficient than old. Replace old fluorescent T-12 (1-1/2 inch) lamps and magnetic ballasts with T-8 lamps (1 inch) and electronic ballasts. Use compact fluorescents in place of incandescent bulbs. Compact fluorescent bulbs that work in coolers are now available.

Stores with high ceilings may consider metal-halide lamps with bi-level ballasts that allow the wattage and the lighting levels to be reduced when less light is needed. High-pressure sodium lamps should be avoided because they give off a pink or yellow color that doesn’t enhance product displays.

Customers and storeowners both benefit from fixtures that tailor lighting to time of use. Walking into a brightly lit store at night can be overwhelming, even painful. At night, lighting can be reduced by as much as one-third without the customer noticing a difference. Many stores use fluorescent fixtures with three bulbs that can be controlled separately. During the day, all three bulbs in the fixture are lit. At night, only two bulbs are lit, and if the store is closed during stocking, only one bulb is lit. This greatly reduces the energy requirements while maintaining worker safety.

Occupancy sensors offer relatively low-cost energy savings in rarely used areas where lights are usually left on. Offices, bathrooms, maintenance closets and storerooms are good locations for occupancy sensors.

Borrowing a page from the retail clothing industry, supermarkets can use spot lighting to attract customers to product displays and save energy in the process. It takes less energy to light adequately for safety and highlight products than to light everything brightly, as most stores do. Energy-efficient compact fluorescent lights can be used for spot lighting and spot reflectors can direct the light. This kind of light adds great effect for sales while reducing energy use.

Thanks to local utilities and the Web, there are many resources to help with energy conservation in lighting. Contact Western’s Power Line for more detailed information about grocery store lighting, or visit Energy Solutions online.

Regular maintenance best way to reduce heating costs
The third-place energy user in a grocery store is heating, since the chilling effect of the refrigerated cases helps to cool the building in warm weather. As with the refrigeration system, regular maintenance is the key to keeping equipment running in peak condition.

One savings opportunity often overlooked is changing air filters. Restricted airflow reduces equipment efficiency and can cause major maintenance problems, not to mention potential health issues. Heat pump systems use a condenser just like the refrigeration unit. Condenser coils must be inspected and cleaned at regular intervals to maintain peak efficiency.

Economizers—devices that allow filtered outside air into the building under the right conditions—can reduce energy used for heating or cooling. In the summer, for example, the store may be getting too cool from the effect of the refrigeration equipment. Instead of heating the store with the heating system, warm outside air can be used to heat the space.

Train, reward employees to build energy-saving habits
A grocery store is a unique blend of industrial equipment operated in a commercial environment. Store staff is focused on selling products rather than maintaining that equipment. Educating the staff is the key to striking a balance between making sales and running an energy-efficient operation. After all, a dollar of product sold is not a dollar of profit if it must be used to pay for wasted energy.

An easy-to-follow maintenance program can help managers keep equipment operating at peak efficiency. Employee training should include simple energy-saving measures like turning off lights, closing doors, cleaning up spills in cases and properly stacking products in refrigerator cases. Enlisting the store’s utility to take infrared photos of display cases is an effective way to demonstrate how stacking affects energy use and product temperature. Incentive programs that reward efforts to save energy are another good way to promote efficiency.

Even small steps can bring big rewards in controlling operating costs. In rural areas, where both independent retailers and power providers are struggling with shrinking customer bases, energy efficiency is an important tool for keeping local businesses healthy.