There are a number of ways that you can increase energy efficiency and reduce energy use simply by maintaining and understanding your existing systems.
Be sure to measure the facility's energy use. You should use an accurate technique such as sub-metering the component usage directly. You can also estimate electricity usage based on nameplate data or amp meter reading, and estimate end-use function based on benchmark data.
To sub-meter, you can use an electro-mechanical meter with a set of split-current transformers. The meter then converts kWh to a selected period. This helps target end-use functions and determine patterns of energy use to help reduce overall costs.
To understand your facility's past and current energy use even better, choose an energy accounting system, which will allow you to record and track energy use, demand, and cost. Share this information with building's operations and maintenance staff and use it to formulate and monitor effective energy conservation strategies.
NOTE: Prior to choosing a system, you need to understand the building's utility bills, energy consumption, energy demand, and rate schedules. Normalize all data for weather, changes in occupancy, and other variables.
Energy Management Systems
Energy management systems measure, monitor, and regulate energy-consuming equipment, and can help reduce labor and energy costs.
Commonly used EMS devices included:
- Timers: turn equipment on and off based on a predetermined schedule
- Occupancy sensors: determine if people are present through heat, movement, or sound
- Programmable thermostats: adjust temperatures based on building occupancy schedules and seasons
- Photocells: regulate light levels
To ensure a properly working system, calibrate and check sensors regularly, protect control devices from power surges, use backup batteries for timers, post safety signs about equipment, and properly train employees.
Regular maintenance will reduce energy usage and help you achieve maximum efficiency.
- Recording refrigerant temperatures and pressures
- Inspecting equipment quarterly
- Checking for leaks
- Examining motor terminals
- Calibrating temperature and pressure gauges.
- Reduces energy usage for maximum efficiency.
Reducing the condenser water temperature set-point in chillers will increase efficiency at partial load. In addition, if your chillers are more than 10 years old, replace them with more efficient models. Currently, the most efficient chiller models will save 0.15 to 0.30 kW/ton over older models.
Install, check and calibrate sensors and electronic controls
Sensors are a less expensive option for areas with varying use, but basic time switches can be used when sensors are not practical. Multi-channel time clocks are flexible, have override features, power backup, durability, and can control multiple devices.
Some additional energy-saving solutions include:
- Thermal energy storage: Cool chilled-water storage tanks during off-peak hours. This allows facilities to use inexpensive nighttime power to cool during the peak day hours.
- Variable-speed drives (also known as Variable-Frequency Drives or VFDs) on water pumps
- Two-speed fanning motors and fan cycling in cooling towers of chillers
- Convert chilled and condenser water configurations to primary-secondary loop: use two-way valves, and variable flow control
If you want to make sure that your green initiatives take hold and have a lasting impact, here are some additional ideas that can help:
Energy management and certification programs
Use energy certification programs to leverage efforts to reduce energy use. Some certification programs include:
- ENERGY STAR: joint collaboration between US Department of Energy and Environmental Protection Agency to set, track, and measure energy goals, performance, and results.
- ISO 50001: assists facilities in planning, managing, and improving energy performance.
- E3: partnership between government, utilities, and industry to improve sustainability in the manufacturing sector.
- LEED: US Green Building Council program that provides a framework for sustainable building design and operational and maintenance practices.
Senior management support
Build a strong case to support energy-efficient projects and present those findings to senior management. This includes:
- Specific goals
- Financial metrics (payback rate, cost analysis, life cycle)
- Competitor comparison
- Positive impact on company's risk and security factors
It is also necessary to build a strong foundation (EMS strategy), sustain momentum, and broadcast results (reports, benchmarking, branding program). A thorough presentation that shows the real value in energy-efficient strategy will help build a foundation to win support for future innovative investments.
Quality power analysis
More than 80 percent of power quality problems are internal. By analyzing the cost of protection against potential power quality incidents, you can see the value of reducing the impact of transients, voltage dips, phase imbalances and other power disruptions.
NOTE: Place electronic controls on circuits with surge protection or an uninterruptible power supply to help address these issues.
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