CitiesGoGreen -September 2008 - (Page 22) High Performance Buildings Forging a path to net zero Several high profile initiatives in action today, including the 2030 Challenge and Cascadia Green Building Council’s Living Building Challenge, call for net zero energy buildings by a date certain. “While net zero is a worthy goal, these buildings are not easily attainable with today’s technologies and building practices,” said Hewitt. “But that doesn’t mean that progress can’t be made.” Hewitt encourages thinking of high performance building as a continuum that begins with the basic level of advanced design for new commercial construction projects and ends with the creation of buildings that can produce all the energy they need on-site through renewable resources (net zero). Buildings can get 20 to 30 percent beyond code with a set of simple, prescriptive measures, mostly upgrades of various building components. Savings beyond that level require design or system changes, or advanced technology options. Where current practices fall on that continuum isn’t as much of an issue as whether or not cities and others are doing what’s necessary to keep moving up the curve. Advanced codes and prescriptive paths “Codes set the lowest limit of acceptable building practice, so energy codes define the least efficient buildings that should be constructed,” according to the Building Codes Assistance Project (BCAP). As such, a building must be 20-30 percent better than current national code stanmodel energy codes. Buildings that dards to meet the minimum level of effifollow Core Performance can qualify ciency on the high performance building for up to five LEED points. continuum. Because getting 20-30 percent be- Getting to 50 yond current model codes is relatively The halfway point on the continuum—50 straightforward, Sue Coakley, executive percent or better efficiency—is the nearDirector of Northeast Energy Efficiency term goal for new high performance conPartnerships (NEEP), suggests that states struction projects. Currently, only one new and communities start with that level as a building in 1,000 is built to the standard, code requirement. Two prescriptive building Where current practices fall on the continuum design options are also availisn’t as much of an issue as whether or not able to help design teams reach the benchmark: cities and others are doing what’s necessary to • ASHRAE (American Socikeep moving up the curve. ety of Heating, Refrigerating and Air Conditioning Engineers) has developed Advanced which is required to qualify for the tax inEnergy Design Guides, a series of centives offered by the Energy Policy Act publications providing recommen- of 2005, according to NBI research. dations for achieving energy savings Nearly all the qualifying projects inover the minimum code require- clude consistent technology applications: ments of ANSI/ASHRAE/IESNA Stan- daylighting, integrated control systems, dard 90.1-1999. The initial series of high efficiency electric lighting, buildguides have an energy savings target ing envelope and HVAC systems. Less of 30 percent and each addresses a common features include major system/ specific building type. design changes such as natural ventila• Advanced Buildings Core Perfor- tion and ground source heat pumps. A mance is a step-by-step simplified ap- database describing these buildings and proach to achieve predictable energy other information can be found at www. savings in small- to medium-sized gettingtofifty.org. buildings without the need for modBuilding to the 50 percent standard is eling. The program brings together attainable given today’s technology and over 30 criteria defining high perfor- design practices although the knowledge mance in building envelope, lighting, base is not widespread and the practice HVAC, power systems and controls remains uncommon. This benchmark is a that when applied result in buildings good candidate for tax rebates, efficiency up to 30 percent more efficient than program incentives or other voluntary solutions. As the knowledge base increases over time, this level can become part of future codes. “If we can create serious markets at the 50 percent savings level, we can start to develop the technologies and designs that save 70 percent or more in just a few years,” Hewitt said. Ultimately net zero The end point on the continuum is buildings that require so little energy they can produce all they need within their footprint through renewable technologies such as photovoltaics. These are often called “net zero” buildings. Estimates are High Performance Buildings continued on pg 31 Getting to 20-30 percent beyond current model codes is relatively straightforward. 22 .com September 2008 http://www.neep.org/ http://www.neep.org/ http://www.ashrae.org/technology/page/938 http://www.ashrae.org/technology/page/938 http://www.advancedbuildings.net http://www.gettingtofifty.org http://www.gettingtofifty.org http://www.bcap-energy.org/node/156 http://www.bcap-energy.org/node/156 http://CitiesGoGreen.com
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