Whole-Building Design – the What and How
Creating a Sustainable Building requires a well-thought-out, participatory process. Sustainable design can most easily be achieved through a whole-building design process. The whole-building design process is a multi-disciplinary strategy that effectively integrates all aspects of site development, building design, construction, and operations and maintenance to minimize resource consumption and environmental impacts. Think of all the pieces of a building design as a single system, from the onset of the conceptual design through completion of the commissioning process. An integrated design can save money in energy and operating costs, cut down on expensive repairs over the lifetime of the building, and reduce the building’s total environmental impact. Process is key. Sustainable design is most effective when applied at the earliest stages of a design. This philosophy of creating a good building must be maintained throughout design and construction. The first steps for a sustainable and high-performance building design include: Creating a vision for the project and setting design performance goals. Forming a strong, all-inclusive project team. Outlining important first steps to take in achieving a sustainable design.
The basic Concept
Recognizing that buildings:
® are complex
® consume vast amounts of energy and material resources over their life time
The 'whole buildings' design approach is:
® a collaborative effort
® a comprehensive evaluation and modeling of materials, systems and assemblies for:
3. future flexibility
5. overall environmental impact
6. productivity and creativity
7. how the occupants will be enlivened
Overview of Whole Building Design Approach
® Bio-responsive building form and massing
® Maximize Passive Heating, Cooling and Daylighting
® Minimize building loads though optimal envelope and glazing design
® Integration of Water, HVAC, lighting, power and control
Goal: to create a successful high-performance building.
1. Apply an integrated design approach during
the planning and programming phases, e.g…
2. Involve all stakeholders in the design process
The owner Design Team
Building occupants Construction Manager
Facilities Management Operation & maintenance personnel
Government agencies Community Groups
3. Act on the premise that all building systems are interdependent
– e.g., modeling the building using all available simulation tools
A Model for the Public Planning and Whole Building Design Process
® Establish Values & Priorities
® Gather Data - Research
® Identify and involve the stakeholders
® Design Charrette – establish design goals/strategies
® Wholistic Design – recognizing independencies
® Commissioning Throughout the Process
® Modeling & Optimization
® Value Analysis/Value Engineering during each phase
® Provide feedback response mechanisms
® Don’t forget the Post-occupancy Evaluation – measure success
The Whole Building Design Process
Establish Energy and other sustainable Goals First - (this is usually accomplished by holding an early Design Charrette or a stakeholder workshop)
Loads Optimization - (based on iterative building simulation)
Design and integrate Environmental and Power Systems - (e.g., Sizing, Building Automation, Integration of renewable energy systems, etc.)
Sustainable strategies life cycle analysis - (use metrics such as net first costs, IRR – internal rate of return, NPV – net present value, etc.)
Value Analysis/Value Engineering - (define user values, simplify, streamline, integrate, tradeoff without reducing those values)
Implement: CD’s, Construction, Installation, Troubleshooting
User Training – how do these systems and methods work, how maintained? Etc.
Post Occupancy Evaluation - (e.g., monitoring, adjustments and certifications – e.g., LEED, Energy Star, etc.)
Note: Commissioning is a continuous process impacting every phase.
Steps in Setting Energy Goals:
1. First: Set Energy Use Reduction Target based on:
1. Organizational values – what are the environmental and moral values?
2. Marketing Strategies – how do these values figure into the overall marketing strategy?
3. Building Type and project parameters – is it new construction, renovation, both and what is the baseline energy use according to ASHRAE 90.1 – 2001 for our type of building? … According to CBECS 2003 averages?
4. Payback requirements – What is the financial imperative for return on investment?
5. Business/Institutional Tax Rate – How much tax incentives can we use to offset our tax rate?
6. Green Building Certification Goals (e.g., LEED silver vs. Platinum) – What other goals are there?
2. Next set renewable energy goals as a percent of energy use or energy cost based on:
• 1-6 above plus:
• Availability of renewable energy
• Available financial resources
Here are the Steps in Setting Energy targets using the Energystar Target Finder:
Enter Project location, type, area, occ. load, etc.
Then we can decide what our goal for energy reduction will be:
• 50% is the minimum value in order to qualify for the full $1.80/SF “Energy Policy Act of 2005: Federal Tax Deduction for Energy Efficient Commercial Buildings” which allows a business tax payer to take a deduction of up to $1.80/SF of building area for qualifying investments in energy efficiency.
• Note the Source Energy values compared to Site Energy Use. This is the true measure of the impact on emissions that building energy use has since the source value takes into account transmission losses and the various efficiencies of generating power. Obviously there is greater efficiency for burning fuel on-site than for producing electricity off-site. This table gives the average electric component for each building type in column three.
Throughout the process we need to involve everyone on the design team so that as we refine our goals and design strategies, they can be successfully integrated into the overall design by every discipline.
Optimize building loads through Whole Building Design:
Optimizing Building Loads involves:
•Establish low-energy, high performance building design as a goal from the outset.
• Site and orient the building to maximize southern exposures and minimize western exposures and to respond to local climate conditions, natural landscape features, and nearby services.
• Optimize use of daylight and passive solar gain - window area and orientation, glazing, overhangs, etc.
• Conduct energy performance and lighting analyses, using tools that account for the interactions between lighting, envelope, and mechanical systems (e.g., DOE 2.2, ENERGY-10, Energy Plus and Radiance.
• Design mechanical, electrical, lighting, and other systems to reduce energy demand.
• Consider the building’s location, envelope, intended use, hours of operation, occupancy levels, and equipment loads in determining HVAC requirements.
• Ensure that the building envelope has adequate insulation and that windows are sized and located appropriately, according to site-specific heating, cooling, and ventilation needs, and make sure the envelope incorporates high-performance glazing and other energy-efficient materials.
• Remember that increasing efficiency of water use reduces the need for energy to produce hot water.
• Ventilation is a huge energy consumer in commercial buildings and so HRV’s, economizer cycles, and heat recovery exhaust are all important.
• Specify energy-reduction targets and sustainable strategy requirements in all contracts.
• Select contractors for their demonstrated expertise in low-energy design and construction, and their experience with commissioning.
Underfloor Ventilation System and Daylighting Diagram for the Gap 901 Cherry Office Building in San Bruno, CA. Loren Abraham, AIA, Design Architect with William McDonough + Partners.
Designing Using Computer Simulations
Optimizing Thermal insulation for walls and roofs
This example shows that the optimal wall type for this building and application (stone veneer on CMU backup) in Grinnell IA is between R21 and 25.
The thermal performance of any building entails complex interactions between the exterior environment and the internal loads that must be mediated by the building envelope and mechanical systems. The difficulty is that these various external and internal load conditions and associated utility loads are constantly changing from hour to hour and season to season. Also, the number of potential interacting design alternatives and possible trade-offs is extremely large. Computer simulations are the only practical way to predict the dynamic energy and energy cost performance for a large number of design solutions. Accurate energy code-compliant base-case computer models give the design team typical energy and energy cost profiles for a building of similar type, size, and location to the one they are about to design.
Designing Using Computer Simulations
Optimizing Thermal insulation for glazing in various types of openings:
This example shows the optimal glazing types recommended for this building for various frame and opening sizes.
Designing Using Computer Simulations
Optimizing Building loads is critical in the early stages of design so that the mechanical systems can be correctly sized and designed.
Our 10 Step Process for integration of Renewable Energy Systems
Use an integrated design process to system-engineer the building
Use computer simulations to guide the design process; these help designers analyze trade-offs and examine the energy impacts of architecture and HVAC choices
Simulate and measure the building’s energy performance at design, construction, and occupancy stages
Set specific, quantifiable energy performance goals
Design the building envelope to meet or minimize as many HVAC and lighting loads as possible
Size HVAC and lighting systems to meet loads not met by the envelope
Use daylighting in all zones adjacent to exterior walls or roofs
Install highly reflective surfaces in all daylit zones, especially ceilings
Monitor and evaluate post-occupancy energy performance
Carefully design and implement the use, control, and integration of economizers, natural ventilation, and energy recovery ventilators.