Simple steps to reducing energy consumption
Reducing energy consumption in buildings does not have to be complicated or expensive. Dr Michelle Agha-Hossein of BSRIA puts forward some suggestions.
Driven by the UK’s emission-reduction targets and the fact that existing non-domestic buildings are responsible for about 18% of the UK’s total carbon emissions, it is important to consider energy-saving strategies in the operation of such buildings. However, for energy- saving strategies to be attractive to businesses occupants, satisfaction and productivity should not be compromised. In other words, such strategies should not have negative impacts on indoor environmental quality, the functionality of the interior spaces and the indoor facilities.
The best opportunities for saving energy at workplaces can often be found in the areas of highest consumption — lighting and HVAC systems. To cut energy consumption in these areas, there are many tried and tested technologies currently available. However, without effective control and management of the environmental systems and a positive energy-saving culture among building occupants, the impact of these technologies will be limited. Therefore, to enhance the energy performance of buildings in operation, operators and occupants have vital roles to play.
There are many low-cost or no-cost energy-efficiency measures that operators can implement in their buildings. For example, annual energy audits can be conducted to determine where and how energy is used in the building. An energy audit includes measuring the electricity used by appliances. The appliance can be plugged into a power meter for a day or even a week to get a more accurate record for a particular period. For lighting, the type and number of lamps and their wattage should first be identified. Then the wattage of each lamp is multiplied by the number of hours that the lamp is on each day. The final figure is then scaled up to give an indication of the lighting annual consumption.
In terms of lighting, energy-efficient lamps such as compact fluorescents (CFLs) or LEDs should be used where possible. These lamps provide operational savings, less heat output and longer life expectancies.
If occupancy sensors are integrated into the lighting system, the settings of these sensors should be checked to align with occupancy use.
Also, if daylight sensors are employed, it is important to understand how occupants use window blinds. To alleviate the glare issue, occupants normally put the window blinds down, and most of the time they will not put them back up again. Because blinds are down, artificial lighting with daylight sensors will be fully on when not needed. Occupants should be encouraged and reminded to adjust the window blinds when there is no glare issue, to make the most of daylight.
The layout of workstations can also have an impact on energy consumption. In places where there is a misalignment between artificial lighting and workstations, occupants often need to use additional task lighting to improve the lighting level at their desks — which increases electricity consumption.
It is important for the building operator to know where and when energy is used to set realistic energy saving targets. This can be done by monitoring and measuring both weather-dependent and non-weather-dependent energy consumption of the building. This is particularly useful to ensure HVAC systems are optimised for outdoor conditions and also to avoid significant base load during unoccupied hours. Degree days can be used to support the weather-dependent consumption analysis. Degree days are a simplified form of historical weather data. Degree-day data is freely available from various sources and normally can be downloaded in a simple spreadsheet format.
Energy-efficiency initiatives focused on energy-related occupant behaviour can also help to save energy.
Energy-awareness campaigns, for example, can be created to help making energy saving a culture. The campaign can be done through e-mails, posters and/or presentations. Energy champions can be nominated to support the campaign, provide greater engagement with users and make routine walkarounds. It is also very useful to occupants to have a greater understanding of what building systems are available, how systems work, what the user interfaces are and how they should interact with their building to optimise the effectiveness of the systems. This information can be covered in a simple user guide for occupants.
Dr Michelle Agha-Hossein is a sustainable building consultant with BSRIA.