An underlying goal behind advancements in the building energy sectors, including standards organizations, high performance building design guides, various green building rating systems, and initiatives such as Architecture 2030 is to steadily improve energy performance through technology development and application to the point where Net Zero Energy Buildings (NZEB) will be a practical reality in the years to come. The current level of high performance within the building sector is about 30% better than normal codes, with 50% energy improvement guides now available and Net Zero Energy guides under development for certain building types.
Typically, a NZEB is defined as a building that, over the course of a year, produces the same, or more, energy than it consumes – a formidable challenge. However, in reality, there are few examples of this absolute with many claiming near-NZEB when crossing the 75% threshold of energy performance. The remaining energy can be offset through renewable energy credits, and a stock of buildings this efficient can make the “Smart Grid” more feasible and able to supplement that remaining amount of energy.
It is the last 25% of energy consumption that is the real challenge for achieving true NZEB. As the building envelope, windows, insulation, HVAC systems, lighting and water heating systems approach optimum efficiencies, and with renewable energy is deployed, it is the process loads inside a building that become the biggest slice of the energy pie. Process loads in traditional office buildings are about 25% of the total energy use, although that value can vary. When the building envelope and MEP systems are designed for maximum efficiency, then the process loads can grow to over 60% of the energy load of the building. These process loads are computers, servers, coffee makers, refrigerators, printers, copy machines, elevators, music, etc. and it is a challenge to reduce these loads. There is currently intense research and development in this area with exciting and innovative ideas emerging.
When that last “twenty five” is substantially reduced, then Net Zero Energy Buildings will become more of a common reality. It is this sector where technology advancements and innovative ideas are being aggressively developed and tested. Design teams tasked with achieving NZEB must draw from some of the most advanced green building technologies and methods available today. These projects contribute to the advancement of an industry and are vitally important to the development of knowledge. IT is an exciting time to be in this field. Stay tuned!
