• Topics: Agricultural and Biological Engineering  |   | Energy Extension Service  | Bates, Robert P  | Burnett, Michael S  | Baird, C Direlle  |  Kepner, Karl 

Chapter VII. Small Businesses¹

INTRODUCTION

Two-thirds of the energy utilized by a typical office building in Florida is electricity. The remaining third includes fuel oil, natural gas, purchased steam, hot water, and chilled water. Of the electric energy usage, 40 percent is for cooling, 33 percent for lighting, 12 percent for heating, and 15 percent for delivery systems.

In a typical Florida retail store, 60 percent of the total energy consumption is for lighting; 30 percent for heating, ventilation, and air conditioning (HVAC); and 10 percent for miscellaneous.

In a typical Florida restaurant, 64 percent of the total energy consumed is electricity, and 36 percent is natural gas. In a table restaurant, 45 percent of the energy consumed is for food preparation, 32 percent for heating, cooling and ventilation, 13 percent for sanitation, 8 percent for lighting, and 2 percent for refrigeration. In a fast food restaurant, 36 percent of the energy consumed is for HVAC, 27 percent for food preparation, 26 percent for lighting, 6 percent for food storage, and 5 percent for miscellaneous.

In a typical Florida supermarket, 45 percent of the total energy consumption is for refrigeration, 16 percent for store lights, 12 percent for fans and antisweat devices, 12 percent for heating and cooling, 2 percent for outdoor lights, 2 percent for case lights, and 11 percent for miscellaneous (Table 1).

FOOD PROCESSING

Energy Use

The food processing segment of the U.S. food system is a major user of energy. A 1976 report indicated that food processing accounted for 30 percent of the energy used in the food system (Table 2) (USFEA, 1976). The fuel sources for food processing are natural gas, oil, coal, and utility generated electricity (Table 3). The form of energy required to produce a particular food item varies depending upon the raw commodities being processed. Table sugar can be made from both sugar beets and sugar cane, but the energy inputs for sugar from sugar beets is different than for sugar from sugar cane (Table 4).

The U.S. food manufacturing industry uses approximately 1,452 trillion BTU annually (USFEA, 1974). In a 1974 study 11 processing categories accounted for 59 percent of the processing energy use (Table 5). The top four energy users, in decreasing order, were beet sugar processing, wet corn milling, meat packing, and malt beverages.

The amount of energy consumed in food processing increased 49 percent from 1954 to 1972. This was partly due to a general increase in energy used in all manufacturing and to a shift toward more energy intensive processing of food before retail. Approximately half of the energy required in food processing is used in the production of inputs consumed in the manufacturing process, such as metal for cans, and for production of capital inputs. The amount of energy associated with these inputs has probably been understated since little data is available on many capital inputs.

Brown and Batty (1976) analyzed the energy required to process a can of corn. Husking, removing from the cob, washing and placing in the can, and cooking required 2.74 MJ per can. The energy required in manufacturing the steel can was 4.17 MJ per can and the carton in which the cans were placed amounted to another 0.45 MJ per can. Altogether, the processing and packaging amounted to about four times as much energy as that required to grow the corn. The manufacturing of the can required 1.4 times as much energy as the corn production.

Proving that packaging food requires a far greater use of energy resources than does the growing of that food does not automatically lead to practical alternatives for preservation. Freezing rather than canning food is one option that warrants analysis, but many factors must be considered, such as the length of time the product is held before consumption. For example, the energy required to keep a l-kg package of frozen corn is about 0.188 MJ per day. Accounting only for the electricity to operate a freezer, corn stored for longer than 22 days would require more energy than canned corn; holding for one year would require 17 times as much energy.

Energy Conservation

The first step a food processor should take in controlling energy costs is an energy audit (Brown and Batty, 1976). An audit consists of making a checklist, which includes both major and minor process energy expenditures (Table 6). An energy balance is performed on each item on the checklist. It is then possible to quantitatively attribute energy costs to individual system components. Ultimately, it should be possible to establish priorities and programs to reduce overall energy consumption, based upon engineering, economic and operational considerations.

Once the energy audit is completed, implementation can be initiated. This involves putting into practice the energy conservation and/or recovery activities identified in the audit. The simple or less expensive measures can be initiated as soon as their benefits are clear. However, the more complex and costly practices require a sophisticated analysis and should be programmed over a number of years under the category of capital improvements. Priorities may depend upon cost, engineering and business analysis, as well as predicted future technical and economic developments.

Useful energy conservation/recovery methods are continually being developed for the food industry. Trade associations and their respective trade journals are a practical source of information on energy management and improved food processing techniques. Some valuable journals are Food Engineering, Food Processing, Quick Frozen Foods, Food Product Development, Modern Packaging, Food Production Management, Food Technology, and The National Provisioner. A technical or agricultural library is a likely source of these and other relevant publications.

For waste energy recovery utilize waste heat from plant equipment such as evaporators, dryers, ovens, and air conditioners, increase regeneration in heat exchange equipment, and evaluate co-generation of electricity in steam pressure reduction.

To conserve electrical energy optimize plant power factors, evaluate the need for a power demand control system,

optimize motor sizes with loads, and convert from incandescent lighting to more efficient fluorescent, mercury, or sodium lighting systems wherever possible. Demand side management (DSM) of electricity is receiving a great deal of attention from utility companies. Find out about incentive programs your utility might have.

To achieve boiler and steam efficiency, minimize boiler blowdown, minimize scale buildup to improve heat transfer, improve steam maintenance, repair steam leaks in system, increase boiler combustion efficiency, and insulate all steam and condensate lines.

Size compressors to the refrigeration load, evaluate heat-recovery systems for compressors, and insulate all refrigerant lines to improve the energy efficiency of the refrigeration system.

New food processing facilities can take advantage of current developments in energy conserving system design. Direct-fired systems and continuous processing can improve energy efficiency. The plant's design can provide for waste heat recovery and appropriate ventilation systems. Refrigerant, steam and hot water line insulation, efficient boilers, electrical power monitors, and appropriately sized meters can be installed from the start.

FOOD RETAILING

Energy Management Programs for Departments

The first step in establishing an effective energy management program is to determine a firm's energy usage and costs for the past year. Information about last year's usage can be obtained from utility bills and/or from the billing department of the firm.

It can be very helpful to plot energy usage and costs on graph paper. As an energy management program is implemented and current usage plotted against usage of the previous year, management and employees will see visually the effectiveness of the energy management program. This should provide the stimulus for an even more effective program.

The greatest opportunities exist for energy savings where energy is being wasted. The following list gives some ideas for positive energy saving options by food store area. This organization by food store area permits management to concentrate energy savings efforts on a department by department basis.

Produce, Dairy and Meat Departments

∙Observe proper temperature settings (Table 7) ∙Make sure walk-in cooler doors close complete and lights turn off when not needed.

∙Close doors completely when loading coolers from delivery trucks between trips from dock to cooler.

∙Place refrigerated products received immediately under refrigeration.

∙Don't stack cooler merchandise up to the ceiling. Cooler merchandise should be stored away from coils and fans. Cooler product when stacked vertically should have at least two inches between stacks for proper air circulation.

∙Remove ice build-up on refrigeration components.

∙Stock products removed from cooler immediately in refrigerated display cases.

∙Turn off wrapping machines, heat seal machines, scales, and disposals when not in use.

∙Properly ventilate ice machines.

∙Make sure timers and water levels on ice machines are functioning properly.

∙Clean all filters on refrigerated coils weekly, or as needed according to manufacturer recommendations.

∙Clean cases, including coils, fans, grills, and drains weekly.

∙Observe load limit lines on all refrigerated cases.

∙Don't stack products over return air grills at front of cases or over the shelves on uprights.

∙Use night covers at store closing where manufacturer recommends.

∙Turn off lights on refrigerated cases when store closes.

Frozen Food Department

∙Observe proper temperature settings (Table 7).

∙Freezer and case temperatures should be checked three times per day.

∙All filters on refrigerated coils should be cleaned as needed, according to the manufacturer's recommendations.

∙Case defrost cycle should be functioning properly and at the most energy efficient time.

∙Consider energy saving options listed for the produce, dairy and meat departments for the frozen food department as well.

Bakery/Deli Department

∙When using electric ovens, bake during off-peak hours.

∙Preheat ovens only until the needed temperature is reached.

∙Load ovens to capacity to make maximum use of baking heat.

∙Load ovens as quickly as possible. Use timers to avoid opening oven doors.

∙Use secondary ovens only when baking schedules overlap unavoidably.

∙Turn off ovens and keep closed when not in use.

∙Preheat fryers according to manufacturer's recommendations (usually 7 to 15 minutes).

∙Reduce fryer temperatures or turn fryer off during slack periods.

∙Set thermostats to 325-335 degrees F (162-168 degrees C). Observe load limit on fryers.

∙Use exhaust systems only when cooking. Flame on gas cookers should be entirely blue and should have a firm center cone.

∙Turn down the heat as soon as food begins to boil. Use lids where possible to retain heated air in pot and decrease cooking time.

∙Turn off slicers, grinders, ovens, grills, etc., when not in use.

∙Consider energy saving options listed for the produce, dairy and meat departments for the bakery/deli department as well.

Grocery Department

∙Keep pallet jacks fully charged.

∙Charge pallet jacks during low demand periods.

∙Close receiving doors when not in use.

∙Use air curtains receiving doors.

∙Stack stock away from ventilation ducts.

∙Keep light fixtures clean.

∙Replace old light bulbs before they burn out.

∙Check ballasts in light fixtures for efficiency.

∙Turn off lights on scales when not in use.

∙Use rear checklane belts used only as needed.

∙Use space heaters only when necessary.

∙No loose outlet connections are permitted on cash registers and scales.

∙Don't overload electrical outlets.

∙Turn off electronic cash registers when not in use.

Energy Management Programs for Store Operations

Store Lighting

∙When determining the efficiency of types of lamps used (before replacing lightbulbs), consider wattage, lifetime and illumination (measured in lumens).

∙Relamp to lower wattage bulbs or fluorescent lamps whenever possible.

Replace one bulb with a comparable number of lumens for two bulbs whenever possible.

∙Disconnect the primary side of the ballast when removing fluorescent lamps or energy will continue to be drawn even after the lamp has been removed.

∙Relamp before bulbs burn out. (Old bulbs do not provide as much light as new bulbs even though both consume about the same amount of energy.) ∙Reset timers on parking lot lights according to the changes in natural outdoor lighting.

∙Clean fixtures to provide maximum light reflection.

Store Office and Non-Selling Areas

∙Don't overload wall outlets.

∙Turn off all lights when not in use.

∙All electrical connections should fit snugly to outlets.

∙Turn off adding machines when not in use.

∙Use space heaters only when necessary.

∙Repair leaky faucets.

∙Display "Please Turn Lights Off" signs.

∙Set automatic door timers for maximum energy efficiency.

∙Charge rechargeable equipment during off-peak periods.

HVAC

∙Set thermostats between 65-68 degrees F (18-20 degrees C) in winter and between 78-80 degrees F (26-27 degrees C) in summer.

∙Turn off exhaust fans when not required.

∙If using gas, the pilot light should be solid blue.

∙Change HVAC air filters monthly.

∙Lubricate motors monthly.

∙Install proper insulation and caulking around doors, windows, and exhaust fans.

∙Time controls on heating and cooling equipment so that no two pieces of equipment start up at the same time.

∙Clean all duct systems, coils, burners, and blowers.

∙For back rooms, set thermostats at 60 degrees F (16 degrees C) in winter and 75 degrees F (24 degrees C) in summer.

Refrigeration Equipment

∙Follow manufacturers load specifications. Adjust shelves to the position and sizes recommended by the manufacturer.

∙Set case temperatures to the highest temperature that still allows for proper food preservation.

∙Set timed electric defrost cycles to occur during low demand periods.

∙Check all door seals and gaskets for cracks and other damage.

∙Hold out-of-stocks in refrigeration cases to a minimum to eliminate vacant space that creates warm spots.

∙A trained store employee should have the responsibility to perform all maintenance for refrigeration equipment.

Miscellaneous Areas

∙Operate balers only when filled to capacity.

∙Reduce the amount of hot water used.

∙Set hot water heaters to lowest temperature appropriate for use.

GENERAL RETAILING

Energy Budgets and Surveys

Energy consumption records of fuels and electricity and expenditures for energy are required to prepare an energy budget. The annual energy consumption, in BTU and $'s, and the store's gross square footage must be known to determine potential energy savings (Table 8). About 10 to 30 percent of annual energy costs may be saved by simple, no-cost measures.

Lighting

Lighting costs may comprise up to 85 percent of total utility costs for a retail store. Lighting costs range from 50 cents to $4.80 per square foot, averaging $1.60 per square foot. Savings of up to 70 percent may be achieved by simple and inexpensive alterations.

Lighting efficiency is the amount of light per unit of energy used. It is measured in lumens/watt. Approximately 30 lumens per square foot are recommended for retail sales areas. 100 lumens per square foot is generally adequate for show windows. Lighting reduction reduces electricity costs directly and indirectly through reduced cooling costs. For cooling cost reductions, a general rule is 30 watts of cooling saved for every 100 watts of lighting saved.

Fluorescent lights produce much more light per watt than incandescent lights and last up to 15 times as long. Use low energy ballasts (current limiters). The new types of fluorescent bulbs can be screwed directly into existing incandescent fixtures. These new bulbs typically use 1/4 to 1/3 of the energy of the replaced incandescents for the same light output. Total costs of operating a system relamped with screw-in fluorescent bulbs are reduced, typically to 1/2 of the costs associated with the original system. (Total costs include procurement, energy, maintenance, and replacement labor.) Local lighting is often inefficient, and up to 50 percent savings may be gained by decreasing lamp wattage, replacing floodlights with spotlights of one-half the wattage, replacing general service lights in show windows with reflector and parabolic aluminized reflector lights, removing louvers and grills from reflector hoods and using lower wattage bulb, and using suspended track for spotlighting.

HVAC Systems

Heating, ventilation, and air conditioning (HVAC) costs for a typical retail store range from 65 cents to $2.20 per square foot per year. Up to 20 percent savings is possible by maintaining equipment and proper temperature settings. An additional 20-30 percent savings is possible through capital improvements.

For space heating energy savings reduce over capacity. An oversized system uses more fuel per unit of heat output due to heat losses during "off" cycle. Reduce nozzle size on oil burners. With gas burners, reduce gas pressure or use high-low flame control, tune the burner at least once a year, and properly adjust the air intake.

Make sure thermostats are placed correctly to monitor room temperature and set thermostats at 65-68 degrees F (18-20 degrees C) in winter. Consider the purchase of a day/night clock thermostat. These thermostats can save up to 20 percent annually. With electric systems, limit the number of heating stages used in a multiple stage system, or install a "current valve." For hot water energy savings consider installing a heat recovery system on existing HVAC equipment to heat water or replacing an electric hot water heater with a dedicated heat pump or a solar system. Gas heated hot water is also quite economical in comparison to electric hot water heating. Turn off the hot water heater when its not needed, i.e., nights and weekends and install insulated pipes a smaller tank if possible. For gas hot water heaters, install electric pilot lights; this can save $30-$50 per year.

For air conditioning energy savings set the thermostat no lower than 78-80 degrees F (26-27 degrees C). Replace filters, clean condensing and cooling coils, and maintain coolant level on a regular schedule.

Reducing infiltration is the simplest, most inexpensive and effective way to reduce cooling costs and control excess indoor humidity in conditioned spaces. Make sure the windows are well caulked and the doors are weatherstripped. Build a vestibule around well-trafficked entrance doors, check ceilings and AC duct work for leaks, and seal electrical fixtures.

Insulation is a cost-effective means of energy conservation in many stores. Roof insulation helps counteract winter heat loss and summer heat gain. The roof is the greatest contributor to both. Double glazed windows resist heat loss and gain, but are costly. Solar screening films, blinds, and shutters can be effective in reducing direct solar heat gains.

BIBLIOGRAPHY AND REFERENCES FOR FURTHER READING

"A Guide to Reducing Energy Use Budget Costs," DOE, Apr. 1978, HCP/U60505-01.

"A Guide to Solar Water Heating in Florida," Florida Solar Energy Center, Oct. 1978, FSEC-78-3.

"Agricultural Engineering Facts - Lighting Indoor Plants," FACTS No. 88, Feb. 1977. David S. Ross. Agricultural Engineering Department, University of Maryland, College Park, Md. 20742.

Brown, S.J. and J.C. Batty. 1976. Energy allocation in the food system: A microscale view. Trans. ASAE 199:4:758-761.

Dietz, C.K. and J. Forwalter. 1978. Process energy audit can lower energy costs by 10-30%. Food Proc. 39:6:32.

"Energy Audit Workbook for Office Buildings," DOE, Sept. 1978, DOE/CS-0041/6, UC-95d;f.

Energy Management for the Retail Food Industry. Creative Management Institute, St. Louis.

"Factsheet 10. Energy Conservation Industry," John M. Fowler. ERDA -- Technological Information Center, P.0. Box 62, Oak Ridge, Tn. 37830.

"Identifying Retrofit Projects for Buildings," FEA, Sept. 1976, FEA/D-78/467.

"Instructions for Energy Auditors, Vol. 1 and 2, DOE, Sept. 1978, DOE/CS-0041/12, UC-95d,f.

33 Money Saving Ways to Save Energy in Your Business. (Available as handout material from County Energy Information Centers) Saving Energy and Dollars in Retail Stores. Massachusetts Energy Office. 1978.

Total Energy Management: A Practical Handbook on Energy Conservation and Management -- National Electrical Contractors Association. (Available as handout material from County Energy Information Centers) U.S. Federal Energy Administration. 1974. Industrial energy study of selected food industries.

U.S. Federal Energy Administration. 1976. Energy Use in the Food System.

Van Arsdall, R.T. and P.J. Devlin. 1978. Energy Policies: Price Impacts on the U.S. Food System. USDA Agr. Economic Report No. 407.

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Tables

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry Arrington, Dean.

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