Energy Efficiency Challenges in the Green Building Sector

Green buildings are true marvels of modern engineering, but to ensure these buildings operate effectively there must be a focus on optimal building energy performance, writes GCX's Damon Lapping. 

Written by Damon Lapping

Globally buildings contribute 36% of energy usage and 39% of energy-related carbon emissions during the construction process of the building and the actual building energy usage during its operational lifespan. In recent years initiatives have been taken to reverse this trend by developing the green building concept. Green buildings use environmentally friendly building practices and by nature of their design incorporate the latest energy efficiency technologies. These buildings are typically complex eco-systems on their own managed with sophisticated Building Management Systems (BMS) software and sensors providing a feedback loop to allow the BMS to control how the building is run and optimising energy usage.

Do Green Buildings live up to their superior positioning? The answer to this question is both Yes and No. During the design of the Green Building, it goes through a process of energy modelling to establish an energy baseline for the building and the building is commissioned based on the outputs of this model. Once construction is completed it goes through a process of commissioning to ensure the building is operated as the design intended. Herein lies the disconnect.

Developing an accurate building energy model is challenging because it is difficult to emulate real-world scenarios such as actual building occupancy and the impact of other environmental variables.

Green Buildings like their typical inefficient commercial building counterparts are also prone to a phenomenon known as Energy Drift. Energy Drift occurs over time where the building energy consumption of the building deteriorates over time due to changes in the surrounding environment such as building occupancy levels, lack of building maintenance, changes to the actual building, etc. Building Management Systems are complex systems and are often seen as a “Black Box” that sits in the corner, once configured it’s “set and forget”, but in life the only constant is change. How can we improve the actual operational running efficiency of Green Buildings? Ensuring we are getting the most out of this sophisticated energy efficiency technology of the Green Building, as the surrounding environment changes?

Just as Green Buildings employ feedback technology to adjust how the building is managed from a cooling, heating and ventilation perspective we still need a certain level of human interaction. Data is king and is the new oil in today’s world but data is valuable only if it is used correctly. A building energy performance model should be developed using a well-respected statistical technique known as regression modelling to establish a building baseline. CUSUM and Energy Control charts are extremely sensitive to changes in energy performance. Analysis of this data should be a precursor for any investigation understanding how the building is performing from an energy efficiency perspective. Only once an understanding is gained of how efficiently the building is currently running, an action can be taken to improve the building operations. Green Building baselines should, in theory, be kept as low as possible, high baseloads mean wasted energy as this energy is consumed out of office hours. High baseloads in Green Buildings also have significant negative effects on the buildings operational costs as these loads run 24/7.

Green Buildings are frequently over cooled and overheated due to the superior insulation properties of the building. Clues to this can often be found by interviewing building occupants, action should then be taken by reducing setpoint temperatures and the HVAC run time. The building baseload should also be investigated with a focus on switching off non-essential loads over the weekends and out of office hours. Periodically every few years the building should be re-commissioned as the building environment changes.

In closing, the Green Building innovation has in recent years become increasingly mature and mainstream. Employing the use of sophisticated technology to reduce energy consumption and energy-related carbon emissions. They are true marvels of modern engineering. But to ensure these buildings operate effectively there must be a focus on optimal building energy performance. Ongoing human interaction is required and changes are made to how the building operates as the building environmental variables change. Use of building data is also key to getting this process right and tweaking system components to get the balance right between energy efficiency and building occupant thermal comfort. This is an ongoing process and management systems should be implemented to support this process during the life span of the building.

Damon Lapping is a highly accomplished and top-performing Energy Management Specialist with 10 years of experience in an energy management consultancy delivering a range of energy management services with a superb record of client service and cost-effective fiscal management. He is also a highly skilled Certified Project Manager and Certified Agile SCRUM Master.

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