DESIGN APPROACH FOR SUSTAINABLE BUILDINGS

IBE Consulting Engineers design strategy for energy efficient buildings looks at five areas of the design: building form and location, envelope, materials of construction, systems and equipment, and controls. Good design requires the optimization of all five areas to provide a unified and elegant solution.

BUILDING FORM AND LOCATION

Building Form and Location are usually the first parts of the design to be fixed and can have a major impact on the energy consumption. Important factors to consider are the orientation of the building, surface area to volume ratio, maximum width of the building for daylighting or natural ventilation, shading from existing trees or buildings, local microclimate, and heavyweight or lightweight building.

ENVELOPE

The envelope of the building is also fixed early and is crucial to the overall energy performance. Important factors include the amount of insulation, area of glazing, solar and light transmittance of glazing, external shading, trombe walls, and ventilated glazing. For the new Nevada Museum of Arts in Reno, IBE Consulting Engineers conducted a thermal wall analysis to analyze the impact of different wall configurations on annual energy consumption in a desert environment. At the Temple Bat Yahm Chapel, the firm completed a Glazing and Shading Coefficient Study to determine the most cost effective glazing.

MATERIALS OF CONSTRUCTION

The use of sustainable construction materials for the shell and core as well as the interior spaces and furnishings is a complex issue. There is an increasing concern with indoor air quality and the health effects of off gassing from furnishings, adhesives, and paints.

There is also increasing concern about embodied energy in materials. The embodied energy use can be addressed through the use of recycled and reclaimed materials and through the use of materials, which are locally available.

SYSTEMS AND EQUIPMENT

This is traditionally the area of greatest influence for mechanical and electrical engineers. The maximum benefits can be obtained if the building form, location, and envelope are also optimized. However, it is also possible to make considerable energy savings by maximizing the system efficiency. The number and combination of energy efficient systems is too great to list. It is important to select components of the systems that will operate at maximum efficiency under the selected operating conditions. Important equipment includes: high efficiency electric motors, properly sized chillers, variable speed drives, high efficiency lamps and electronic ballasts, and air side economizer cycle.

Alternative energy sources such as solar power and solar heated hot water may also be investigated. We are currently incorprorating photovoltaic panels on Audubon Visitor’s Center and the Los Angeles Children’s Museum, Hansen Dam. The Audubon Center also utilizes a solar driven chilled water system and solar heated hot water.

CONTROLS

It is critical that the controls are not designed in isolation. Controls should be considered concurrently with systems and equipment. Essentially, controls allow the systems and individual components to work at maximum efficiency. Typical energy saving control systems which should be considered are: occupancy sensors, daylight sensors, supply air temperature reset, optimal start for cooling and heating systems, software light switching systems, and elevator optimization programs. More complex controls, which may be required, are those for slab cooling systems where predictive slow response systems are necessary.

DAYLIGHTING

IBE Consulting Engineers employs advanced analysis techniques to optimize day-lighting schemes. The firm’s daylighting experience includes studies on a variety of projects.

THERMAL ENERGY STORAGE

Thermal Energy Storage - using the mass of a building or the earth to shift peaks in load from periods of high energy cost to lower energy cost - can result in energy savings. The new temple Bat Yahm building complex uses the floor slabs to store coolness from nighttime ventilation to offset chiller demand during the day. This system has received a local utility rebate.

VENTILATION

IBE Consulting Engineers is currently involved in a number of projects in California that involve full or partial natural ventilation.

Current examples of our work in this field are:
• Audubon Visitor’s Center, Pasadena, CA
• Los Angeles Children’s Museum, Hansen Dam, CA
• Casa Blanca Learning Center, Riverside, CA
• San Francisco Federal Building, San Francisco, CA (concept studies)

COST SAVINGS

Intelligent and “sustainable” building design results in cost savings. It reduces operating costs through energy efficient design. It also increases individual productivity and long-term occupant satisfaction.

LIFE CYCLE COST ANALYSIS

IBE Consulting Engineers integrated design approach has enabled significant cost savings on projects. Early in the design process, life cycle cost for tradeoffs of alternative building systems are analyzed and explored to arrive at the most appropriate and cost effective solution. Life cycle costing of systems is an integral and important element of the process of energy efficient design. We have performed life cycle cost analysis on nearly all of our projects.

Maintenance costs and costs of remodeling as well as energy costs need to be considered when comparing different systems. Our engineers insist that these issues be discussed with the Owner’s Operations and Maintenance staff early in the design process.