The Cleveland Green Building Coalition (CGBC) is helping the architecture firm mbi | k2m with a series of workshop discussions and demonstrations as they renovate an existing, two-story building and adjacent parking lot at 3121 Bridge Avenue.
mbi | k2m is spending $1 million to buy and renovate the Ohio City building for its local office, and received an $800,000 commercial redevelopment loan from
The firm will provide open access to the office building as they develop a Leadership in Energy and Environmental Design (LEED)-certified building. The workshop will allow participants to interact with mbi | k2m’s design staff as well as key individuals from the project’s contractor, Nyman Construction Company, and the MEP engineering firm, TES Engineering. Topics will include green design, deconstruction, engineering, and construction monitoring.
At its third session in May, project engineers from Thermal Environmental Systems, Inc. (TES) presented their approach to greening the mechanical and HVAC systems in an existing building.
Essential to a building’s energy performance is involving the engineers from the beginning.
“Early on, we talked about, how efficient can the building run?” said TES engineer John Wirtz. “We weren’t just estimating equipment cost. We were part of the schematic design. We then had a set of plans and we could talk to subcontractors about how that affects cost and (LEED) credits.”
As a result, basic assumptions about the building’s performance were worked out before the architects began designing the space. They had a sense of “what’s definite and what’s not from an engineering perspective.”
For example, energy modeling identified that to bring in 30% more outside air (to get LEED points for ventilation) would have been more energy intensive, so, it was eliminated. Also, a smaller building size meant individual air control (at least 50% of occupants have own control, or own vent) didn’t meet the cost-benefit analysis.
Conversely, they found water saving features like low-flow toilets and faucets an easy and cost effective way to earn points. But, it is in lighting design that they expect to net multiple benefits including lower energy use and less heat output.
“We really tried to keep watts per square foot down,” said TES project manager Dieter Hausman. “We found that by looking at how the space was going to be used, that various lighting levels could drop down to 10 foot-candles. Overall, we dropped way below the average 1 watt /sq ft (to .6) based on efficiency and design and by using fluorescent bulbs and motion control sensors throughout.”
That reduction in heat from lights had a positive ripple effect in selecting the size of the air conditioning unit. mbi | k2m principal Scott Maloney was expecting they would need a 20 ton AC unit, but found a 15 ton unit would suffice. Considering the light systems, the smaller AC unit, the existing R-value of the walls and replacement windows, TES estimates a 20% energy efficiency improvement. Maloney expects to pay a 1% premium for the green features, but to get a two-year payback for the AC unit.
Maloney’s words of advice for those considering a LEED-certified project is be prepared for many more hours of paperwork, which can account for higher costs if you calculate staff time. The benefits, he says, are lower energy bills, improved indoor air quality and worker productivity and positive public relations.
