Considering that buildings are the primary consumer of energy in the U.S., many progressive organizations are pursuing a Net-Zero Energy goal for their facilities. This aggressive goal can be accomplished by significantly reducing energy use through incorporation of energy-efficient strategies into the design, construction, and operation of new buildings and commencing retrofits to improve the efficiency of existing buildings. Most often, use of on-site and off-site renewable energy sources are required to meet the Net-Zero Energy goal.
The concept of a Net Zero Energy Building, i.e., “a building that produces as much energy as it uses over the course of a year”, has recently evolved from research to reality. There are however, currently only a few buildings that meet the criteria to be called “Net-Zero Energy”. As a result of advanced 3D EnergyandDaylight Modeling, improvements in construction technology, building controls and renewable energy systems, the design and construction of Net-Zero Energy buildings has become more practical.
Green Ideas Net-Zero Energy Process
Green Ideas utilizes a five-step process to achieve our client’s Net-Zero Energy goals:
Orientation: To achieve maximum lifecycle benefits and reduced first costs, we work with your design team to properly orient the building towards an east-west axis (when possible) to take advantage of geographic solar opportunities, reduce solar heat gain, and aid in reduction of building energy requirements.
Envelope: After optimum orientation is determined, we focus on the building envelope as a whole in order to minimize energy loads. During the envelope design phase, we utilize Green Ideas’ proprietary Energy and Daylight Modeling process to provide critical information to designers required to meet Net-Zero Energy goals. We perform both Energy and Daylight Modeling to provide design professionals with data required for a sustainable and efficient design. This detailed process is focused on reducing overall energy loads for the building, so that mechanical systems can be “right-sized” to reduce first costs, as well as operations and maintenance costs throughout the useful life of the building.
Mechanical Systems: HVAC systems are often oversized by mechanical engineers, leading to increased initial costs, as well as inflated operation costs. Again, Energy and Daylight Modeling is the key to determining what type of HVAC equipment is best suited for a project, in addition to “right-sizing” the equipment. Properly sizing the HVAC equipment is one of the most important steps towards a Net-Zero Energy goal.
Renewable Energy. After design loads are minimized by applying steps one through three above, we then examine renewable energy applications. We conduct a detailed renewable energy analysis to determine how much renewable energy will be required to meet the building’s reduced energy needs and achieve the Net-Zero Energy goal. This analysis minimizes the amount of renewable energy systems required, further reducing initial and lifecycle costs.
Building Energy Systems Commissioning: A critical part of a Net-Zero Energy strategy is to perform Building Energy Systems Commissioning before occupancy. Commissioning is a systematic process by which all energy-using equipment within the building is inspected to confirm proper operation so that optimal performance is achieved. We begin this intensive quality assurance process during design and continue through the end of construction. Commissioning ensures that the new building operates initially as the owner intended and that facility management staff are prepared to operate and maintain its systems and equipment. Ideally, an ongoing commissioning (retro-commissioning) program should be initiated to ensure that energy systems continue to operate as designed.
Since the ” Net-Zero Energy” concept is relatively new, there are not any absolute, widely accepted zero-energy metrics. The National Renewable Energy Laboratory (NREL) has several definitions for “net-zero energy”, and the organization encourages design, construction, and facility management professionals to choose the metric that is best for their specific project.
Whichever definition or metric used for your Net-Zero Energy building, minimizing energy use (and thereby maximizing energy efficiency) through attention to detail by utilizing advanced Energy and Daylight Modeling techniques should be a fundamental design element for all Net-Zero Energy projects. When done properly, energy efficiency is typically the most cost-effective strategy with the highest return on investment. By using advanced energy analysis tools and technologies, design teams can optimize the energy performance and create efficient designs to meet client’s Net-Zero Energy goals.
Summary
In pursuing this new standard of building operation, we assist in the lifecycle planning for the building that begins in the design phase and continues through operation and maintenance. A crucial element towards achievement of this goal that is commonly overlooked, is the holistic approach that should begin in the programming phase to clearly communicate to all parties that a Net-Zero Energy goal will be achieved.
During the design phase various tools will be utilized, such as Green Ideas’ proprietary Energy Modeling that will provide critical information for design decisions to be made in congruence with Net-Zero Energy use. Our process is focused on reducing overall energy requirements of the building, then examining renewable energy applications after the loads are reduced.
During the construction phase, Commissioning of the Building’s Energy Systems will be executed to verify that the installation of all energy-using systems has been completed properly to meet the performance specifications and owner’s project requirements. Building Envelope Commissioning may also be implemented to ensure peak performance.
Throughout the operation and maintenance phase, we provide resources to establish a proper measurement and verification protocol to help track the ongoing use of energy in order to validate that the goal of Net-Zero Energy is met for the life of the building. Benchmarking tools like ENERGY STAR will be utilized to assist in tracking the energy data and compare the project to similar building types. We also manage the LEED for Existing Buildings (LEED-EB) certification process to ensure that the building continues to perform as Net-Zero Energy. Click to see our portfolio of certified projects.
