Advancing Building Energy Performance

Building energy codes are intended to mandate the highest level of energy efficiency that can be achieved cost-effectively. They set a standard that adjusts as building technologies improve, energy costs vary and the overall importance placed on energy conservation changes.

The recognition of climate change as a serious concern has helped make energy codes more aggressive, and so has innovation in the industry. Widespread adoption of voluntary programs, such as ENERGY STAR and LEED, have designers and owners demonstrating new ways of making buildings more efficient.

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Energy codes first appeared in the U.S. in the 1970s, when congress mandated them in response to the 1972 oil embargo and subsequent energy crisis. ASHRAE led the way releasing the first version of what is now Standard 90.1 in 1975. The federal government is not allowed to mandate a national energy code; energy codes are adopted and enforced by individual states. The federal government can, however, link financial support to state energy policies, according to Paul Torcellini of the National Renewable Energy Laboratory. “The current requirement for states to upgrade their codes is tied to whether the state accepted American Recovery and Reinvestment Act of 2009 (ARRA) funds,” he says.

States adopt either the most recent version of ASHRAE 90.1 as their code (sometimes with modifications), or they adopt the International Energy Conservation Code (IECC), which is based on 90.1 (except for single-family and low-rise multifamily homes—IECC has its own process for developing the residential energy code).

The 2010 update to ASHRAE Standard 90.1 was the most ambitious revision in the standard’s nearly 40-year history. On average, buildings will have to be 18 percent more efficient to meet 90.1-2010 compared with 90.1-2007, according to a U.S. Department of Energy analysis. In turn, LEED continues to encourage even higher levels of efficiency: under LEED v4, new buildings have to beat Standard 90.1-2010 by at least 5 percent, and most will have to do much better than that to achieve the coveted Gold or Platinum certification levels.

Achieving that kind of energy efficiency cost-effectively requires engineers to expand their view beyond just taking responsibility for a building’s mechanical or electrical system, and instead actively work to address energy use for the building as a whole. Fortunately, that kind of shift in consciousness is underway, as seen, for example, in the 2012 rebranding of ASHRAE that removed the specific reference to “heating, air-conditioning and refrigeration” from the organization’s name. Now ASHRAE members are simply “shaping today’s built environment for tomorrow.”

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Great building performance also demands close collaboration by all members of a building’s design and construction team, which is why LEED v4 has a new Integrative Process credit to help coordinate that kind of teamwork. When team members take a broader view of their role and work effectively across the disciplines, highly efficient buildings can have minimal upfront cost premiums and huge returns, both for their owners and for the environment.

 Advancing Building Energy Performance

Generic Mechanical and Electrical BIM Objects for the NBS National BIM Library

by Andi Connelly Horsley, NBS Technical Author

The NBS National BIM Library will soon be issuing a significant number of generic mechanical and electrical BIM objects. These will help building services engineers visualise their designs and implications at concept design stage, giving the architect and other design team members an appreciation of what is required at a very early stage in the project. The generic objects can then be easily replaced by proprietary (manufacturer's) objects as the project develops.

Within each object, several parameters have been made variable, such as connection diameters and positions, and main object dimensions (length, width and height). Objects are intended to represent a wide range of the most frequently used plant and equipment.

One of the most important properties of the generic objects is clearance and detection zones. These provide the user with space requirements and clash detection knowledge early on in the design. For example, BS 5839-1 sets maximum spacing requirements for heat detectors. This is reflected in the object by way of coverage area. The detection zones of an object then enable the engineer to easily position and calculate the number of detectors required. The aim is to reduce the potential risk of having to make expensive design changes later on in the project lifecycle.

As the project progresses and the design evolves, generic objects for plant and equipment may be replaced with proprietary objects (from NBS Plus or the manufacturer). This provides the opportunity to immediately assess the effects on project objectives, such as performance and cost, and eventually produce information such as the building's carbon footprint.

Feedback from many areas of the construction industry has been used to generate NBS National BIM Library's generic mechanical and electrical objects. Objects are by necessity:

  • Geometrically accurate and instantly recognisable;
  • Of variable dimensions and connection type, to ensure maximum flexibility;
  • Produced complete with identifiable and visual detection zones where appropriate;
  • Complete with clearance/maintenance zones; and
  • 'Non-hosted'; that is, they don't have to be fixed to a wall or a ceiling when brought into the project.

The NBS National BIM Library has included plant and equipment such as:

Fire and detection equipment: Control and indicating equipment, detection (i.e. point heat and point smoke detectors, beam detectors), mimic panels, manual call points and sounders.

Intruder detection and alarm systems: Control and indicating equipment, detectors (including PIR, PIR and microwave, beam and acoustic), and sounders.

LV distribution equipment: Cubicle switchgear, distribution boards and consumer units.

Road and amenity lighting: Lighting columns, brackets and bollards.

Water services: Calorifiers, water heaters (both storage and instantaneous), pumps, booster sets, pressurization units, expansion vessels, storage tanks and solar collectors.

Heating plant and equipment: Boilers, heat exchangers, pumps, emitters and heat pumps.

Ventilation and cooling: air handling units, condensing units, chillers and spilt coil units.

NBS National BIM Library generic mechanical and electrical objects are produced in Autodesk Revit, as extensive research and analysis indicates that this is the tool of choice for service engineers implementing BIM. However, all objects are also in IFC (Industry Foundation Classes) format, an industry-wide open and neutral data format that enables rich data exchange without the dependency on any one software package. All of the mechanical and electrical objects are available from the NBS National BIM Library in both Revit and IFC format, accompanied by an 'Object Guide' in PDF format. This lists all parameters involved in the use of the object, including: NBS (which directly relate to NBS Create specification writing software), COBie (Construction Operations Building Information Exchange) and IFC. It also provides a description for each parameter from the NBS in-house technical author engineers, and BuildingSMART.

The team at NBS are continuing to interpret and simplify the BIM process - and present it in a user-friendly way. As Ian Chapman, Director of the National BIM Library says, "No-one understands construction information requirements better than NBS".

Generic Mechanical and Elec1 Generic Mechanical and Electrical BIM Objects for the NBS National BIM Library
Wall mounted, gas-fired condensing boiler.
Image produced using Revit.

Generic Mechanical and Elec2 Generic Mechanical and Electrical BIM Objects for the NBS National BIM Library
Wall mounted, gas-fired condensing boiler in position in Revit,
with the clearance zone indicated.

 Generic Mechanical and Electrical BIM Objects for the NBS National BIM Library

10 predictions for the US building industry

green building 3 300x225 10 predictions for the US building industry

Portland/Seattle green builder Hammer & Hand has unveiled its ten predictions for the US high performance building industry.

These include:

  • Focus will move beyond Net Zero Energy to Net Positive Energy buildings.

Three trends will begin moving the high performance building industry beyond Net Zero Energy (NZE) buildings toward Net Positive Energy (NPE) buildings:
a. Falling prices for photovoltaic panels to make energy production more feasible;
b. Increasing viability and availability of electric vehicles to harness surplus energy production and compete with buildings for electricity; and
c. The emergence of market mechanisms that reward both onsite energy conservation and production (see next point).

  • Market mechanisms that reward energy conservation and renewable energy production will flourish.

Market-based tools like Feed In Tariffs (to allow building owners/operators to sell excess energy back to the grid), Carbon Offsets (to reward building owners/operators for reductions in carbon footprint), and Metered Energy Efficiency Transactions (to allow investors in building energy efficiency to sell “negawatts” back to the utility, being piloted by the Bullitt Center and Seattle City Light) will continue to gain ground in 2014.

  • Building energy codes will move away from prescriptive rules toward performance-based measures.

The City of Seattle leads the charge toward performance-based code at the municipal scale, and the States of California and Washington have taken important first steps at the state level. The US Department of Energy continues to push the envelope through its work on the International Energy Conservation Code. Expect the trend toward performance measures to continue in 2014 as the limitations of prescriptive code become more and more obvious to policy makers.

  • CO2 heat pumps will help transform heating and cooling performance.

New technology will continue to drive the development of the US high performance building industry, with CO2 heat pumps making an entrance into the North American marketplace. These heating and cooling units bring these benefits:
a. More earth friendly due to lower Global Warming Potential (GWP).
b. Move more energy more efficiently.
c. Work in much colder climates without the steep performance curve drop-offs seen with other heat pumps.

  • The US-led move to make Passive House more climate-specific will improve performance at both micro and macro levels.

In the past year the Passive House Institute US began spearheading the effort to make the Passive House standard more sensitive to the diverse climates found across the US, including partnerships with the Building Science Corporation and the Department of Energy. This effort will bear fruit in 2014, helping to guide successful high performance building in the American South and across the northern portion of the continent.

  • Europe’s push to eliminate thermal bridges in buildings will make high performance building more mainstream in the US, too.

Europe is pushing hard to eliminate thermal bridges (building elements that transfer heat or cool energy through the building envelope), resulting in a wave of new user-friendly software tools for calculating thermal bridging. This development has brought what was once a highly technical, niche element of high performance building into the mainstream in Europe. These same tools apply equally well in the US, and promise to make the battle against thermal bridges easier to win for US designers in 2014.

  • China’s interest in high performance building will propel US market.

While still nascent, China’s move toward high performance, energy conserving structures and building envelopes will have far-reaching impacts. From demand for US-manufactured building components to supply of Chinese-made ones, the US high performance building industry stands to gain when the world’s second largest economy puts its weight behind building energy conservation.

 10 predictions for the US building industry