Traditional approaches to decreasing building energy use and improving operations still tend to overlook low-cost and no-cost improvements. Recommissioning offers another tack to practical, immediate performance improvements.
New incentive programs, several related points in the LEED (Leadership in Energy and Environmental Design) Existing Buildings: Operations and Maintenance (EB:O&M) rating system and an expanding portfolio of successful case studies across North America further reinforce the rationale.
It is, therefore, no surprise Toronto’s Civic Action’s Race to Reduce – with more than 50 million square feet of commercial office space signed up to reduce energy consumption by 10 per cent by 2014 – is focusing on the recommissioning process as the weapon of choice to generate those savings.
Recommissioning is a holistic approach to comfort, energy, capital expenditure, operations and maintenance. It is not an energy audit where a consultant hunts for energy conservation strategies largely driven by capital-intensive measures such as replacing all lighting with higher efficiency bulbs and ballasts. Nor is it a request for a proposal-driven process, in which strategic control of assets are handed over to a third party.
Holistic approach
Recommissioning focuses on right-sizing the building’s mechanical and electrical systems and their operation for today’s conditions, not those in place when it was built. That might mean, for example, examining key design calculations to determine that the oversized pump is not in fact necessary.
Recommissioning includes a utility analysis to highlight areas of energy and cost concern. It focuses on ensuring equipment is doing what it was supposed to do, when it’s supposed to be doing it. It allows for updating fresh air volumes and revised sequences of operation according to current requirements. It tests and documents all key components and puts in place documentation and methodologies for ongoing monitoring and testing to ensure the building doesn’t drift once it’s running properly.
Recommissioning is a four-phase process that includes planning, investigation, implementation and hand-off.
Phase 1: Planning
This is where the building owner or operator identifies the target building and develops the project scope. That entails selecting the candidate building, establishing a project team and determining the objectives – for example, improved comfort, generation of sorely lacking building documentation and energy conservation.
Existing data and case studies show the most successful projects have been in commercial office buildings at least in the 50,000-square-foot range, and with a building automation system already in place.
Phase 2: Investigation
The project team reviews current documentation, begins a diagnostic and witness testing of all key building systems, compares occupancy to existing schedules and generates a master list of findings to summarize what can be done to save energy and resolve operational issues.
Notably, simple fixes can be made quickly. If a damper link is broken, it can be fixed on the spot. Or a lighting control or air handling unit schedule can be altered to reflect changed occupancy.
As part of the investigation, the current capital expenditure program should also be reviewed. There is no point recommending changes to a system scheduled for replacement in another 18 months.
Key areas to scrutinize include the elimination of unnecessary ventilation, simultaneous heating and cooling, and confirmation that lighting control is both appropriate to occupancy and is functioning as expected.
Phase 3: Implementation
This is all about prioritizing items for implementation – for example, complete work, commission, document, monitor and communicate the changes.
Phase 4: Hand-off
This is a key point. Everyone involved needs to understand what has changed, where it’s documented and what the ongoing expectations are in terms of operations and maintenance.
This is the time to celebrate success but there should also be a scheduled periodic repetition of testing, known as ongoing recommissioning, which is where the sustaining of savings comes in.
Business case evidence
The Lawrence Berkley National Laboratory in California completed a comprehensive review of 90.4 million square feet of recommissioned building space in 2004, subsequently updated in 2009. It identified typical energy savings of 16 per cent for an average payback of 1.1 years. That’s a return on investment of 90.9 per cent. Median costs were $0.30 per square foot.
Not surprisingly, the more energy intensive a building is, the greater the scope for low payback savings. This does not begin to account for non-energy savings such as fewer tenant complaints, improved equipment life and ongoing operational savings from having proper documentation in place.
A recommissioning exercise is now in progress in six Oxford Properties buildings encompassing more than 4.5 million square feet of commercial office space. Measures are primarily focused on upgrades to existing building automation systems, focusing on elimination of off-hours usage and updating operational parameters to reflect current usage and standards as opposed to those in place at the time of construction. Through an investment of $0.24 per square foot, an average payback of 1.8 years has been generated, or an return on investment of 54 per cent.
Ian Sinclair is manager of existing building services at Enermodal Engineering, which is conducting the re-commissioning project for Oxford Properties.
