High Performing Buildings - Fall 2011 - (Page 65)

frequency drives with premiumefficiency motors on the main fans for two of the buildings. (The VFD/motors on the third building main fans were replaced years before when the original equipment needed to be replaced for maintenance reasons.) Prior to the recommissioning, the occupied mode for the facility’s heating and cooling systems would activate at 3 a.m. and not return to setback mode until midnight; this control scheme was in effect seven Lessons LeaRned early collaboration by a multidisciplinary team of owner representatives, architects, engineers, specialty consultants, and other vested parties is key to understanding project priorities and interactions among various buildings systems. For example, the siting and orientation of a building by the architect directly affects mechanical and lighting systems with respect to solar gain and levels of natural daylight entering building spaces. Foster a creative environment for the entire design team to explore unconventional ideas. The developer’s original vision for golden Hill involved conventional building shaping and orientation primarily because that was how a typical speculative office building was designed to keep construction costs in line. Partner with a third party institution that can offer high-level technical consulting to implement leading-edge technologies. For golden Hill’s original design, seri provided guidance and coordination services that helped deliver a high-quality, innovative design. seri personnel were sensitive to the developer’s financial constraints and never insisted on implementing any particular technologies. seri also brought an energy modeler on board. understand that the siting/orientation of a building will have impacts that can never be undone. golden Hill was sited on top of a hill and laid out in an east/west orientation, which enabled the facility’s designers to harness the potential of the sun. days a week. The recommissioning reconfigured the occupied and setback modes to activate at 6 a.m. and 7 p.m., respectively, during the work week. On the weekends the facility is in setback mode. Golden Hill earned LEED-EB Silver certification in 2009. Reconsidering PV While passive solar heating and solar hot water systems were integrated into Golden Hill’s original design, photovoltaic panels remained on the facility’s wish list for many years since the upfront costs were prohibitive. The cost equation changed at the time of Golden Hill’s LEED-EB certification efforts due to rebates offered by the local utility company and government tax credits. With these incentives, Golden Hill’s owner installed three roofmounted 10 kW photovoltaic arrays at a 64% reduction in capital cost. From installation in January 2008 through Aug. 24, 2011, the three photovoltaic arrays have A green/sustainable building does not have to be substantially more expensive. By being creative and open to new ideas, golden Hill’s designers evaluated ideas that, on the surface, may have appeared to be cost prohibitive. An example was the evaporative cooling system, which became cost feasible by not installing chilled water backup. investigate potential rebates, tax credits, and other incentives from third-party institutions when trying to improve the energy efficiency of your building. A technology that may be too costly may become affordable by tapping into such cost-saving opportunities. This proved to be the case with golden Hill’s addition of roof-mounted photovoltaic arrays, reflective roof enhancements, and air fan variable frequency drives with premiumefficiency motors. sustainable/green buildings not only reduce costs in terms of energy and water use, they provide more comfortable, inviting spaces for building occupants and increase marketability. golden Hill’s occupancy rate in mid2011 was at 97% even in a down economy. While a number of factors may be contributing to this figure, the building owner, in recent years, has been emphasizing the facility’s sustainable design features to prospective and existing tenants in marketing literature and signage. Fanless cooling towers (located on the roof) were specified with the original building design since the design team was concerned a conventional type cooling tower might create vibrations and disturb fifth-floor occupants. A fanless cooling tower is less efficient than a conventional type cooling tower since more pumping pressure is required to evaporate the cooling tower water. With a fanless cooling tower, part load operation is also more difficult to accomplish. However, when these cooling towers were replaced with towers utilizing fans in 2004, resulting vibrations were not realized. if the building had higher ceilings, more space could have been allocated to larger overhead ductwork, which would have reduced horsepower to move air through the spaces. in addition, higher ceilings would have allowed more daylight glass, allowing deeper penetration of natural light into the building spaces. However, given the city-mandated 60 ft building height limit, golden Hill’s developers would have had to set the building deeper in the hill or eliminate a floor to allow for higher ceilings. These options were not considered for financial and logistical reasons, respectively. golden Hill’s engineers designed a threestage direct evaporative cooling system, primarily for the increased control compared to a one-stage system. The overall cooling system was comprised of an indirect/direct evaporative system; this “lesson learned” only relates to the direct component of that overall system. Although a three-stage system provides a marginal increase in control compared to a one-stage system with bypass control, it presents additional complications related to operations and maintenance. (The three-stage direct evaporative cooling system uses a series of three 4 in.-thick direct evaporative media sections compared to a series of one 12 in.-thick direct evaporative media sections used by a one-stage system.) Fa l l 2 0 1 1 HigH PerForming Buildings 65

Table of Contents for the Digital Edition of High Performing Buildings - Fall 2011

High Performing Buildings - Fall 2011
Commentary
Contents
Manitoba Hydro Place
Maplewood Police and Court Building
Omega Center for Sustainable Living
Dockside Synergy at Dockside Green
Golden Hill Office Center
Letters to the Editor
Products
Advertisers Index

High Performing Buildings - Fall 2011