Schneider Electric explains two methods that can be implemented in order to decrease energy consumption and consequently reduce overall energy costs: sub-metering and daylight harvesting.
As energy costs continue to rise and compliance laws change, there is growing pressure to reduce energy consumption and improve energy efficiency in order to drive down costs and meet increasingly demanding energy efficient building requirements.
When utility costs can exceed 30 percent of your overall operating expenses, knowing when, where and how your operation consumes energy is vital. Lighting is one of the biggest culprits of a building’s energy usage, accounting for between 20 and 50 percent of total energy costs.
Implementing the most recent technologies and strategies to track and monitor your facility’s current lighting and power usage, and adopting a lighting control system, can help achieve significant savings.
Not only is understanding your energy consumption a key component to reducing overall operating costs in the base building, but it is now law. Under the Commercial Building Disclosure (CBD) scheme, all sellers or lessors of office space greater than 2000 square metres are required to obtain and disclose an up-to-date base building energy efficiency rating. The CBD scheme is the first regulatory step in making business more energy wise and penalties will apply for non-disclosure. Tenancies are only required to do lighting assessments. Organisations that are committed to energy reducing activities will reap the benefits.
Two methods that can be implemented to decrease energy consumption and consequently reduce overall energy costs are sub-metering and daylight harvesting.
SUB-METERING: TRACKING PERFORMANCE INDICATORS
Sub-metering is the installation of metering devices to measure energy consumption at specific points within a building. It is an effective way to understand energy consumption, recognise power quality issues, identify waste within a facility, and measure and track key performance indicators, such as watts per square metre, occupancy, total tenant load, common area costs and carbon footprint.
Before doing anything, it’s critical to establish an energy usage baseline to help identify the most effective course of action for a building. Additionally, without a baseline, there is no way to know later on whether energy efficiency measures identified as part of a strategic energy management plan are working. The first step involves collecting data for major energy consuming applications (for example, lighting, lifts and air-conditioning) and analysing the impact of these applications on total consumption. One of the most effective methods of accomplishing this is through power metering and monitoring.
Power meters are devices installed at various points within a facility’s power distribution system. The role of power meters is to record how much electricity is used in a circuit and thereby provide critical data about the areas within a facility that need to be addressed. These devices can also measure power quality. Poor power quality, or power that is rife with voltage sags and swells, can have a negative effect on facility components and contribute to substandard performance and unplanned downtime. Energy management software converts the raw consumption data from power meters and monitoring system into historical data that can be studied to identify areas that require attention.
Once these areas have been identified, the easiest fixes should be made first, such as installing more energy efficient lighting fixtures and luminaires. While these passive energy efficiency tactics can translate into substantial savings, continuous energy improvement over the life cycle of the facility and changing conditions should be the ultimate goal.
Automation options that create energy and cost savings are more substantial than passive measures. Lighting control systems, for example, can automatically turn interior and exterior building lights on and off based on a pre-set schedule, instead of relying on personnel to remember.
DAYLIGHT HARVESTING: MAXIMISING ENERGY EFFICIENCY
Daylight harvesting is the use of a control system, such as DALI control, to reduce the use of artificial lighting in building interiors when natural daylight is available. Studies have shown that, by using daylight harvesting technologies, owners can obtain average annual energy savings of 24 percent. Daylight harvesting should form part of an overall lighting control initiative, along with high efficiency lighting ballasts and luminaires, and pre-programmed lighting schedules.
Daylight harvesting controllers include an integrated real-time clock with automatic daylight savings correction, sunrise and sunset calculation, and holiday exceptions. Control schedules can be configured in a daylight harvesting controller to automatically switch and vary lighting levels to harvest daylight and enforce energy savings. Sensors can be incorporated into the network to provide automatic dimming to compensate for the amount of natural light.
Additionally, many daylight harvesting controllers are equipped with reporting tools to provide the energy data needed to ensure a building is delivering on its energy targets and continuing to meet green building ratings. The installation of a daylight harvesting controller enables the maximisation of energy efficiencies and the achievement of higher energy efficiency ratings.
A strategic energy management plan helps ensure energy and cost savings don’t erode over time. Power meter installations, monitoring services, energy efficiency analysis and energy bill verification can all help achieve this.
