Lowering energy use, elevating building performance

Net-zero energy buildings can be achieved with smart building design. Here are tips on how to design a high-performance building.


Learning objectives

  • Understand and reconsider the definition of high-performance buildings.
  • Learn the two-step approach to net-zero: reduce, then produce.
  • Understand total occupant comfort.

This article has been peer-reviewed.The National Renewable Energy Laboratory's (NREL) definition of a net-zero building is a building that generates enough renewable energy on-site to equal or exceed its annual energy use. Net-zero energy design is a reality. We can achieve it today without the need for futuristic technologies. The questions we should be asking ourselves are: Is net-zero enough? Is net-zero the end goal? How does the pursuit of net-zero design impact the overall performance of the built environment?

According to Architecture 2030, nonresidential buildings consume 47.6% of all energy used in the United States annually. The sheer volume of energy consumed by buildings is one of the biggest, if not the biggest, contributor to carbon emissions and global warming, and that is only going to increase.

Design industry leaders, including ASHRAE and AIA, have established clearly defined goals for achieving net-zero design by 2030. The aim of ASHRAE Standard 189.1: Standard for the Design of High-Performance, Green Buildings is to provide an iterative road map toward achieving net-zero design by the year 2030.

A critical step on the path to net-zero design is ensuring that engineers and architects reduce the energy use of the building while elevating environmental performance as it relates to the overall health and comfort of occupants. This two-pronged approach to high-performance building design can lessen energy consumption and increase productivity. Ultimately, buildings can be positioned as a key component of the solution toward decreasing emissions and improving the environment.

Figure 1: Building simulation tools such as options from Integrated Environmental Solutions (IES) are essential to accurately predict daylight glare and associated energy impact in order to best apply available budget to achieve a net-zero energy goal. Building simulation tools allow the design team to optimize, quantify, and present both energy and occupant comfort design strategies and demonstrate compliance with ASHRAE Standards 90.1, 62.1, and 55. Courtesy: DLR GroupHigh-performance: A new definition

Net-zero energy design is an iterative and collaborative process. Setting clear expectations within an integrated project delivery (IPD) team is important. An integrated team consisting of the owner, architect, engineer, contractor, and all vested partners must have a clear understanding of how the building will be designed, built, and operated with clearly outlined high-performance goals. High-performance environments should be the ultimate aim for design teams.

Perhaps it’s time to redefine high-performance. DLR Group believes high-performance buildings should be net-zero (or net-zero capable) buildings that maximize occupant comfort and productivity.

Figure 1: Building simulation tools such as options from Integrated Environmental Solutions (IES) are essential to accurately predict daylight glare and associated energy impact in order to best apply available budget to achieve a net-zero energy goal. Building simulation tools allow the design team to optimize, quantify, and present both energy and occupant comfort design strategies and demonstrate compliance with ASHRAE Standards 90.1, 62.1, and 55. Courtesy: DLR GroupThis vision of a high-performance building requires the traditional design process to evolve. A more integrative and holistic process with a focus on early decisions in the design phase and rigorous performance simulation is necessary. Building performance simulation and energy analyses are vital to establish indoor environmental and energy optimization criteria. Also important is a clear understanding of the anticipated use of building spaces to fully inform the design. An initial visioning session must establish measurable high-performance goals based on the building's anticipated operations protocol.

Project energy budgets now take on as much significance as project cost budgets. Establishing energy and budget targets early in the design, and then tying systems analysis and evaluation to both project cost and energy budgets are critical to ensuring the project stays on track for energy consumption goals within the financial budget.

Synergies between engineered systems must be evaluated and presented to key stakeholders as part of a holistic analysis. At this time it’s essential to share projected energy and operational savings along with first costs to illustrate the positive impact on occupant comfort, and the total cost of ownership (TCO) of the building. If a building owner is to invest in a high-performance glazing system, then the associated reduction in chiller and boiler plant size, and the associated energy and maintenance cost reductions must also be presented as a TCO comparison.

Yet we don’t want to design bunkers. We want compelling, beautiful buildings that elevate the human experience through design.

Two consistent challenges must be overcome to produce buildings that achieve our new vision of high-performance design:

  1. An emphasis on value engineering to lessen first costs versus operating costs
  2. Thoughtfully considering occupant comfort and productivity through the entire design process.

Cost conundrum

A building’s initial capital costs and operational costs are often derived from different funding sources. This can pose a significant challenge in pursuit of high-performance if value engineering and minimizing first costs becomes the primary driver of the design process. Acquiescing to investor and/or owner demands to lower first costs during design can have negative long-term impact on occupant comfort and productivity. This does not have to be the case any longer.

The Research Support Facility at the National Renewable Energy Laboratory, Golden, Colo., is a 360,000-sq-ft office building that generates as much electricity as it uses. It uses rooftop photovoltaics for on-site production and was built for the same price as a traditional Class A office building. NREL’s “Controlling Capital Costs in High-performance Office Buildings: A Review of Best Practices for Overcoming Cost Barriers” white paper further documents that it is feasible to design and construct buildings that can achieve net-zero energy goals with standard first cost considerations.

A holistic, value-based building performance analysis is key to any net-zero design project. As part of performance analysis the design team must be disciplined, maintain focus, and champion the importance of elevating energy performance to the level of schedule and budget for the project. This ensures that both energy goals and budget priorities are managed and optimized throughout the design process rather than addressed in individual value engineering exercises. When a clear business case for a high-performance design strategy has been presented to the project team through a quality performance analysis, it is much easier to retain that strategy during a traditional value engineering process.

The engineering team has learned that focusing purely on reducing energy consumption during design will not guarantee high performance. A focused reduction of energy consumption must go hand-in-hand with designing spaces to optimize occupant comfort.

A commitment to ensuring occupant comfort in the design process to produce a small increase in productivity can potentially offset annual operational costs during a building’s operational lifecycle. A user-friendly, high-performance building with healthier and happier occupants can provide opportunities to enhance the morale of employees, improve operations, return a premium for owners through increased rents, and ultimately reduce operating costs.

During a building’s lifecycle, its use changes and the needs and perception of occupants also change. A design that cannot bend and shape to evolving user needs cannot deliver a state of mind that expresses satisfaction with the surrounding environment.

When users are not comfortable, they take action to modify their environment. We see this every day. Personal space heaters seemingly appear overnight. Next are fans of all shapes and sizes. Then a power strip for that heater, the fan, and the needed mini-refrigerator. Perhaps some curtains or posterboard to block glare. A book or trash can might be placed over the diffuser. In the end, all of this extra equipment and modification alters system performance and ultimately energy use and performance.

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