Part 2: ESCOs: Success Starts with Identifying Energy-Efficiency Targets
ESCOs: Success Starts with Identifying Energy-Efficiency Targets
By James Piper, P.E. - November 2012 - Energy Efficiency
Once managers have identified the organization's goals, the next step is to identify the most cost-effective way to achieve them. In most cases, this means working closely with the ESCO to identify potential projects that would generate the desired energy savings or load reductions. The most comprehensive way of identifying these projects is through an energy audit.
An energy audit is a detailed survey of the facility that reviews how and where the facilities use energy and determines where the potential exists for energy savings. For each potential project, the energy auditor develops a preliminary estimate of the project's cost and cost savings.
Typical energy audits have four targets: lighting systems, HVAC systems, building controls, and building envelopes. The audit must examine all of them to be effective.
Lighting systems offer some of the most cost-effective energy conservation measures. The most common lighting-system measures involve upgrading to more efficient light sources, reducing light levels to match the requirements of the space, or installing automated controls that limit the operation of the lighting system to those times when occupants actually need light.
When looking to improve the operating efficiency of HVAC systems, managers must evaluate a range of options, such as replacing existing components with higher- efficiency units, closely matching system capacities to needs, performing neglected maintenance, or balancing air and water systems so they provide optimal levels of heating and cooling.
Improperly operating building-control systems are a major source of energy waste in facilities, and they can significantly reduce equipment service lives. Energy audits frequently identify sensors that are out of calibration, poorly or incorrectly operating control sequences, inappropriate system set points, and equipment operating schedules that fail to match space use requirements.
Finally, the audit will identify areas on the building's envelope that need more insulation, new door and window seals, upgraded glazings, and shading devices to reduce solar thermal loads.
These are the most common targets of energy audits, but it is important that the audit go beyond these items. For example, audit should consider the energy and cost benefits of on-site generation of electricity from conventional or renewable sources, particularly for facilities looking to reduce their peak electrical demand.