There are many systems that offer substantial energy-saving potential in wineries, including refrigeration and cooling systems, compressed air systems, lighting, and packaging systems; there are even savings to be gained in tasting rooms and gift shops. As a result, wineries can benefit greatly from a variety of strategies that are easy to implement and that are either free or cost very little.
Turning Things Off
Turning things off seems simple, but remember that for every 1,000 kilowatt-hours (kWh) you save by turning things off, you save $120 on your utility bill, assuming an average electricity cost of $0.12/kWh.
Lights. Turn off lights when they are not in use. Occupancy sensors and timers can help, but a less expensive alternative is simply to develop standard protocols for shutting lights off during closed hours—particularly in tasting rooms and gift shops.
Electronic displays. Many stores or tour areas have electronic displays that are left on even after open hours. Consider shutting off the displays during closed hours, either manually or with simple timers.
Turning Things Down
Some equipment cannot be turned off entirely, but turning it down to minimum levels where possible can save energy.
HVAC temperature setbacks. During closed hours, turn temperature settings down in warming seasons and up in cooling seasons. Smart thermostats can help automate this process.
Peripheral and back rooms. Make sure that HVAC settings in stockrooms, offices, and other peripheral rooms are at minimum settings.
Refrigeration and Cooling
Because refrigeration and cooling generally use the most electricity in wineries, they are often a great starting point for making energy-efficiency improvements.
Tank insulation. Making sure that the storage tanks used for fermenting and aging wine are well-insulated is an easy and effective way to reduce energy consumption. Multiple types of insulation are available, including spray-on (for large applications), foil-covered bubble wrap, and rigid foam. According to BEST, adding insulation to tanks should generally reduce refrigeration energy use by about 25 percent, though exact savings will vary depending on the specific tank and insulation used.
Install floating head pressure on glycol chillers. Glycol is the standard refrigerant for industrial facilities because it absorbs heat efficiently. BEST states that allowing glycol chiller head pressure to “float” based on outdoor wet-bulb temperatures can reduce the power consumption of the refrigeration compressors by 5 to 20 percent.
Raise the temperature and pressure setpoints. Tartrates—small crystals that form when tartaric acid mixes with potassium in the wine at low temperatures—are tasteless and odorless, but they’re considered unsightly. They are frequently removed using a process called cold stabilization, which requires wine to be chilled to between 25° and 36° Fahrenheit (F) and then reheated. This process is only necessary when the wine can’t easily be maintained at the optimal 59°F due to cold outdoor temperatures.
Also, refrigeration systems will run at higher efficiencies when operated at higher suction-pressure setpoints. Raising glycol temperature will raise the associated suction pressure; this change can result in a savings of 2 to 3 percent of refrigeration compressor energy for each degree increase in suction temperature.
Nighttime air cooling. Bringing in low-temperature outside air during the night to provide cooling can reduce electricity consumption and lower peak power use during the day. This is particularly effective in spaces where outside-air circulation was not previously required, such as warehouses, offices, and cold-stabilization areas. According to BEST, savings can easily add up to about 20 percent of overall cooling energy.
Air infiltration through doors. By employing air sealing and ensuring that doors between refrigerated and nonrefrigerated areas are properly closed whenever possible, BEST estimates you can save as much as 15 percent of your total refrigeration energy consumption.
Properly sequence compressors. Compressors operate most efficiently at full load. In a refrigeration system that employs multiple compressors, the most efficient operation entails sequencing compressors based on their loads and respective efficiencies and ensuring that only one compressor at a time operates at part load.
Packaging and Bottling
Conveyors are widely used in bottling and palletizing; in many facilities, they run even when not fully loaded. Only running conveyors when they’re necessary can reduce energy consumption and demand while also conserving lubricants and water. Automation controls can make conveyer management easier, though it can be done manually as well.
Although compressed air is often viewed as an essentially free resource, BEST estimates these systems typically account for nearly 10 percent of overall electricity consumption in wineries, and they’re often poorly designed or maintained. Optimizing compressed air systems can lead to significant savings.
Match your supply to your load. Generate compressed air only at the pressure required—halving pressure can result in energy savings of more than 50 percent, according to BEST. Additionally, sequence your machines to ensure that when the demand is at less than full capacity, some compressors are entirely shut off, rather than having several operating inefficiently at part load.
Check for leaks. Air leaks in a compressed air system are a major source of energy loss—they can as much as double the cost of compressed air. Because leaks also result in lower pressure at the point of use, they can cause operators to set pressure levels higher than would otherwise be necessary. Leak detectors can cost anywhere from $1,000 to $15,000 to install, but they will often pay for themselves the first time they’re used on a system that hasn’t been maintained (Table 1).
Table 1: Leak detector savings
The US Department of Energy’s Advanced Manufacturing Office measured the energy savings, dollar savings, and simple payback periods of finding and repairing compressed air system leaks in four industrial facilities.
In many wineries, lighting accounts for 8 to 20 percent of electricity consumption. Improving the efficiency of your lighting systems can be a straightforward and inexpensive way to save energy.
Employ daylighting. Daylight can improve the ambience of an office and reduce the need for electric lighting. Dimming ballasts and daylighting controls can be used to reduce the amount of electric light needed when daylight is present.
Install occupancy sensors. Areas that are not consistently occupied—such as storage rooms, restrooms, back offices, and walk-in refrigerators—are ideal places for occupancy sensors. BEST estimates that lighting these low-usage areas only when they’re in use can save between 30 and 75 percent of the lighting energy consumption in those areas; occupancy sensor installations typically yield simple payback periods of one to three years.
Cleaning and Maintenance
Making sure that your HVAC system is regularly cleaned and serviced can help prevent costly heating and cooling bills.
Check the economizer. Many air-conditioning systems use a dampered vent called an economizer that draws in cool outside air when it is available to reduce the need for mechanically cooled air. If not regularly checked, the linkage on the damper can seize up or break. An economizer that is stuck in the fully open position can add as much as 50 percent to a building’s annual energy bill by allowing hot air in during the air-conditioning season and cold air in during the heating season. Have a licensed technician check, clean, and lubricate your economizer about once a year, and repair it if necessary. If the economizer is still operating, have the technician clean and lubricate the linkage and calibrate the controls.
Check air-conditioning temperatures. With a thermometer, check the temperature of the return air going to your air conditioner and then check the temperature of the air coming out of the register that is nearest the air-conditioning unit. If the temperature difference is less than 14°F or more than 22°F, have a licensed technician inspect your air-conditioning unit.
Change the filters. Filters should be changed periodically—every one to six months. More-frequent changes may be required when the economizer is in use, because outdoor air is usually dirtier than indoor air.
Check the cabinet panels. On a quarterly basis (or after filters are changed), make sure the panels to your packaged rooftop air-conditioning unit are fully attached, with all screws in place and all gaskets intact so that no air leaks out of the cabinet. Chilled air leaking out can cost $100 per rooftop unit per year in wasted energy.
Clean the condenser coils. Check the condenser coils quarterly for either man-made or natural debris that can collect in them. At the beginning and end of the cooling season, thoroughly wash the coils.
Check the airflow. Hold your hand up to the registers to ensure that there is adequate airflow. If there is little airflow, or dirt and dust are found in the register, have a technician inspect your unit and ductwork.