The four phases of an energy retrofit require flexibility and creative thinking
As buildings age, their owners and managers face the daunting challenge of keeping them operational with new technologies. Generally, a lack of funding means facility owners and managers must figure out how to reduce energy usage.
Accounting for nearly all existing commercial space, private commercial buildings present the largest untapped opportunity for energy-efficiency retrofits. However, federal and state facilities and other institutional buildings are more likely to receive funding and, therefore, have more opportunities for energy-efficiency retrofits.
So, what exactly does an energy-retrofit project involve? An energy retrofit for an existing building can be divided into phases, such as:
- Energy audits and retrocommissioning.
- Energy-analysis modeling.
- Energy-conservation measures and prioritization.
- Design implementation, construction, and startup.
Energy Audits and Retrocommissioning
The energy-audit and retrocommissioning phase of an energy-retrofit project generally consists of making an inventory of the major pieces of equipment and system-operating controls and analyzing their efficiency. As part of this phase, existing equipment undergoes retrocommissioning so its performance can be observed. It is important to collect data on existing utility bills and rate structures, which may have been negotiated with facility owners or federal agencies.
Energy-analysis modeling involves understanding utility-bill details as well as creating a base energy model for the building and its existing systems. A base model is critical to the analysis because predicting energy savings depends largely on the building's current operation.
Energy-Conservation Measures and Prioritization
Working with facility owners and managers to introduce innovative ideas and energy-conservation measures produces returns on investment while achieving energy savings. Such projects can include variable-speed drives, lighting retrofits, chiller and boiler replacements, variable-refrigerant-flow systems, and condensing-water heat recovery.
Implementation, Construction, Startup
The final phase of the process involves construction-documentation development, implementation of conservation measures, and startup. It is important that existing conditions be well-documented and accurate drawings be produced.
Challenges of this phase can include existing-equipment locations, accountability, and hours of operation. For example, during a recent energy-retrofit project, a firm was charged with developing extensive phasing plans for a federal courthouse that involved moving occupants from one phase of the project to another without disrupting the facility's activities. Because of the sensitivity of the documents stored at the courthouse and the high-level employees involved, construction could be performed from 6 p.m. to 4 a.m. only. Additionally, all of the construction/installation sites had to be cleaned up at the end of each shift. The extensive phasing not only had an impact on the labor cost, but required detailed planning on how to bring materials into the facility and phase the work being performed.
Some of the contributing factors instrumental in achieving energy-efficiency goals can be obtained by changing major pieces of equipment, such as introducing chillers with digital scroll compressors or boilers with condensing sections that provide efficiencies greater than 90 percent.
Vice president and director of KAI Design & Build's mechanical, electrical, and plumbing engineering group, Promod Kumar, PE, has more than 35 years of experience as a mechanical engineer. A former two-term member of the Missouri Board for Architects, Professional Engineers, Professional Land Surveyors, and Landscape Architects, he has been involved in renewable-energy projects and energy modeling for federal and state facilities.