Getting it right in mixed-use buildings: Sustainability
Mixed-use buildings—often a combination of retail and residential—are unique structures with varying needs. Energy-efficiency systems typically are requested by building owners.
Michael Albanese, PE, LEED GA, Senior Associate, Kohrs Lonnemann Heil Engineers, Fort Thomas, Ky.
David Callan, PE, CEM, HBDP, LEED AP, QCxP, Vice President, McGuire Engineers, Chicago
Donna Miller, PE, PEng, LEED AP, Vice President, Engineering, WD Partners, Dublin, Ohio
Gary Poole, PE, Principal, Bury Inc., Houston
Andrew H. Smith, PE, CEM, LEED AP, Principal, Jordan & Skala Engineers, Dallas
CSE: Energy efficiency/sustainability is often the No. 1 request from building owners. What net zero energy and/or high-performance systems have you recently specified on a mixed-use project?
Miller: Some of the sustainable concepts we have specified recently include VRF, HVAC, solar water heating, and daylighting controls. These systems were not specified to achieve net zero, but to achieve energy saving for the building owner.
Smith: Several high-performance systems specified include HVAC systems, LED site lighting, LED parking garage lighting, and open-ended design allowing for future installation of solar photovoltaic.
Callan: Mixed-use buildings are by nature an odd duck. Seldom will you see a mixed-use building with homogenous ownership and/or occupancy. I would argue that, in fact, sustainability is much lower on the totem pole for stakeholders than one might want to admit. For instance, energy and maintenance costs are passed through to tenants and represent a small fraction of the overall rent. Greenwashing and marketing have made real sustainability and responsibility difficult to distinguish.
CSE: Many aspects of sustainability (power, HVAC, maintenance, etc.) require building personnel to follow certain practices to be effective. What, if anything, can an engineer do to help increase chances of success in this area?
Callan: Listen to your client. A wise mentor once told me: "You have two ears and one mouth for a reason."
Miller: As with any type of success, knowledge is power. Educating the building personnel on the systems, how they work, and why these systems are valuable to the operation of the building is a key to success. If the building personnel operating and maintaining the systems agree with the system selection and maintenance procedures, the sustainability and energy efficiency features will be enhanced.
Smith: Verify that staff members who are using the building are trained in the building systems. Additionally, ensure the buildings are commissioned to ensure proper setup and documentation of systems.
Poole: All too frequently the operational staff are not part of the design discussions and do not fully grasp why the systems are designed in the manner that they are. The earlier that the operators of the facility can be brought into the design dialogue, the better. When it is not possible to bring the operational staff into the design meetings, the design team needs to take the time to review their design with them as early in the process as possible. It is key for designers and operational staff to review all of the aspects of the design together so that the operators will know how the systems should be controlled.
CSE: Please share a mixed-use success story in which you were able to enhance the sustainability of a building. Annual statistics on energy savings and other supporting evidence would be helpful.
Albanese: For a recent major urban mixed-use development over a several-block area, we designed to a LEED Gold standard, including energy improvements of 25% over and above what is required by code. The building and parking facilities were designed for the smallest possible footprint. Potable water use was reduced by 30% compared to code requirements. Occupant air quality and comfort was improved through a designed 30% increase in the outside air, which exceeded code requirements. Additionally, the design allowed occupants access to the light and outdoor views in 75% of the occupied spaces.
Smith: West 7th Street N.E. Block in Fort Worth, Texas, is a new 110,000-sq-ft, seven-story, LEED Silver-certified shopping, dining, and entertainment venue. The project encompasses nearly five city blocks and features boutique shopping, fine dining alternatives, and an array of unique nightlight options. The development appeals to a broad range of people including local residents, cultural-district visitors, students, the central business district, and medical center employees. Jordan & Skala Engineers provided MEP and LEED engineering design, which enhanced the sustainability of the development in a number of ways. Ultra-low-flow plumbing fixtures were used to achieve a 40% savings in water use. The commercial-office HVAC system consisted of self-contained water-cooled air handlers on each floor with a roof-mounted cooling tower. Additionally, increased outdoor air ventilation was employed for enhanced indoor air quality. West 7th has won numerous awards including the Building of America Award 2010 and Texas Construction magazine's Topping Out Award 2010.
CSE: Please describe your experience in smart or intelligent mixed-use buildings.
Smith: Smart electric meters installed in dwelling-unit meter centers and retail areas allow each tenant to see electric energy usage on a near real-time usage, generally the day before.