Energy Efficiency Guide for Colorado Businesses

Recommendations by Sector

GROCERY STORES

Energy Use

Grocery stores have long operating hours and a complex mix of energy demands. Primary energy use is for lighting (34%) and product refrigeration (30%). Grocery stores that have food service and food preparation areas can have high water-heating loads, representing 10% or more of total energy use. HVAC constitutes most of the remainder of the load in grocery stores, roughly 25%. Many grocery stores are overlit by older fluorescent lamps that suffer from poor color rendering and inefficiencies.

Measures that are frequently found to be cost-effective include the following:

Refrigeration

• It is usually worthwhile to upgrade refrigeration systems in grocery stores to include efficient, state-of-the-art technologies. Include dewpoint controls for anti-condensate heaters on refrigerated cases so defrosting is matched to actual need. Incorporate efficient cooling system components such as high-efficiency compressors, water-cooled condensers, floating-head pressure controls, and multiple, unequally-sized compressors feeding the same manifold.
• Install floor insulation in coolers. The floors of some walk-in refrigerators in many grocery stores are simply concrete slabs that are neither insulated from the earth underneath nor around their edges. Retrofitting these with floor insulation improves cooler efficiency.
• Use efficient lighting in refrigerators and save twice: this retrofit lowers the electricity use for both lighting and cooling.

High-Efficiency Lighting

• Replace T-12 fluorescent fixtures with T- 8 or T-5 fixtures with electronic ballasts. Select bulbs with good color rendering. Lower color temperatures (5,000 K or below) give a warmer “feel” to products. Using uplight fixtures eliminates hot spots in the ceiling area, gives shadow-free illumination of the products below, and enables good visual acuity at lower lighting levels. This contributes to making shopping less frenetic and lowers lighting and cooling costs.
• Install and adjust automatic dimming controls to take advantage of daylighting and enable lowering light levels for restocking and cleaning while the store is closed.
• Install and adjust occupancy controls in warehouse areas.
• Install LED exit signs.
• Upgrade parking lot lighting to save energy and reduce environmental impacts due to light spillage. Light fixtures which illuminate areas that don't need it or the sky itself produce light spillage.

High-Efficiency HVAC

• Install a demand-controlled ventilation system. When only a few people are in a store, energy can be saved by decreasing the amount of ventilation supplied by the HVAC system. A demand-controlled ventilation (DCV) system senses the level of carbon dioxide in the return air stream and uses it as an indicator of occupancy. DCV can save energy during peak cooling periods when many shoppers are at work and occupancy is low.
• Install variable air volume air handling systems with variable speed drives.
• Choose high-efficiency packaged A/C units listed by the Consortium for Energy Efficiency in their Tier 2 guidelines (www.cee1.org/com/hecac/ac_tiers/impcttbl.htm).
• Downsize to a new high-efficiency chiller in conjunction with lighting and refrigerator case retrofits. Sizing the HVAC equipment to take into account the cool air leaking from cases and cabinets can usually justify downsizing the chiller, offsetting the higher first cost of high-efficiency equipment.
• Use condensing boilers with large turn-down ratios whose efficiencies improve with turn-down.
• Switch over to direct digital controls.
• Install premium-efficiency motors.
• Upgrade the energy management system; optimize settings to reflect usage, respond to changing weather patterns, and control peak electric loads.
• Continuously commission the building.
• Consider evaporative cooling.

Building Envelope

• Install high-efficiency glazing carefully chosen for each building facade's relation to the sun and other variables. When installing new glazing, choose a product that has high transmission in the visible spectrum (to enhance daylighting within and view from inside and out) but low transmission in the infrared (low solar heat gain coefficient, SHGC, and low emissivity in the far infrared, “low-E”) to enhance energy performance during the cooling season. Install overhangs to limit direct beam sunlight coming in store windows.
• Install insulation in strategic areas.
• Undertake air sealing, including duct work and door weather stripping.
• Install an ENERGY STAR cool roof that has high reflectivity.

Plug Loads

• Use low-energy sleep functions on computers, printers, and copiers.
• Choose ENERGY STAR commercial refrigerators, water coolers, and other appliances.

Employee

• Ensure that stockers, building maintenance people, and cleaning staff are enthusiastic about savings and adopt work habits that support energy efficiency.
• Involve all employees in energy savings efforts, provide efficiency education for work and home, and encourage employee suggestions on energy savings opportunities.
• Track energy use and utility bills and investigate anomalies. Document energy savings and report results to management and employees.

Combined Heat and Power (CHP) System

• Install a combined heat and power system to supply electricity, heating needs, and (through an absorption chiller) cooling needs. When properly sized and designed, such a system can save substantial money and avoid the large thermal losses associated with conventional power generation at utility plants.

 

Funding for this Guide provided by:

Colorado Governor's Energy Office

U.S. Environmental Protection Agency - Region 8

Southwest Energy Efficiency Project

Recommendations for this and other sectors are available at www.coloradoefficiencyguide.com/recommendations.