Advanced Interactive Facades - Critical Elements for Future GreenBuildings?

Building designers and owners have always been fascinated with the extensive use of glass in building envelopes. Today the highly glazed facade has almost become an iconic element for a 'green building' that provides daylighting and a visual connection with the natural environment. Even before the current interest in green buildings there was no shortage of highly glazed building designs. But many of these buildings either rejected sunlight, and some associated daylight and view with highly reflective glazings or used highly transmissive glass and encountered serious internal comfort problems that could only be overcome with large HVAC systems, resulting in significant energy, cost and environmental penalties. From the 1960's to the 1990's innovation in glazing made heat absorbing glass, reflective glass and double glazing commonplace, with an associated set of aesthetic features. In the last decade there has been a subtle shift from trying to optimize an ideal, static design solution using these glazings to making the facade responsive, interactive and even intelligent. More sophisticated design approaches and technologies have emerged using new high-performance glazing, improved shading and solar control systems, greater use of automated controls, and integration with other building systems. One relatively new architectural development is the double glass facade that offers a cavity that can provide improved acoustics, better solar control and enhanced ventilation. Taken to its ultimate development, an interactive facade should respond intelligently and reliably to the changing outdoor conditions and internal performance needs. It should exploit available natural energies for lighting, heating and ventilation, should be able to provide large energy savings compared to conventional technologies, and at the same time maintain optimal indoor visual and thermal comfort conditions. As photovoltaic costs decrease in the future, these onsite power systems will be integrated within the glass skin and these facades will become local, non-polluting energy suppliers to the building. The potential for facilitating sustainable building operations in the future by exploiting these concepts is therefore great. There is growing interest in highly glazed building facades, driven by a variety of architectural, aesthetic, business and environmental rationales. The environmental rationale appears plausible only if conventional glazing systems are replaced by a new generation of high performance, interactive, intelligent facade systems, that meet the comfort and performance needs of occupants while satisfying owner economic needs and broader societal environmental concerns. The challenge is that new technology, better systems integration using more capable design tools, and smarter building operation are all necessary to meet these goals. The opportunity is to create a new class of buildings that are both environmentally responsible at a regional or global level while providing the amenities and working environments that owners and occupants seek

High-Performance Integrated Window and Façade Solutions for California

The researchers developed a new generation of high-performance façade systems and supporting design and management tools to support industry in meeting California’s greenhouse gas reduction targets, reduce energy consumption, and enable an adaptable response to minimize real-time demands on the electricity grid. The project resulted in five outcomes: (1) The research team developed an R-5, 1-inch thick, triplepane, insulating glass unit with a novel low-conductance aluminum frame. This technology can help significantly reduce residential cooling and heating loads, particularly during the evening. (2) The team developed a prototype of a windowintegrated local ventilation and energy recovery device that provides clean, dry fresh air through the façade with minimal energy requirements. (3) A daylight-redirecting louver system was prototyped to redirect sunlight 15–40 feet from the window. Simulations estimated that lighting energy use could be reduced by 35–54 percent without glare. (4) A control system incorporating physics-based equations and a mathematical solver was prototyped and field tested to demonstrate feasibility. Simulations estimated that total electricity costs could be reduced by 9-28 percent on sunny summer days through adaptive control of operable shading and daylighting components and the thermostat compared to state-of-the-art automatic façade controls in commercial building perimeter zones. (5) Supporting models and tools needed by industry for technology R&D and market transformation activities were validated. Attaining California’s clean energy goals require making a fundamental shift from today’s ad-hoc assemblages of static components to turnkey, intelligent, responsive, integrated building façade systems. These systems offered significant reductions in energy use, peak demand, and operating cost in California

The design and evaluation of three advanced daylighting systems: Light shelves, light pipes and skylights

We present results from the design and evaluation of three advanced daylighting systems: a light shelf, a light pipe, and a skylight. These systems use optical films and an optimized geometry to passively intercept and redirect sunlight further into the building. The objectives of these designs are to increase daylighting illuminance levels at distances of 4.6-9.l m (15-30 ft) from the window, and to improve the uniformity of the daylight distribution and the luminance gradient across the room under variable sun and sky conditions throughout the year. The designs were developed through a series of computer-assisted ray-tracing studies, photometric measurements, and observations using physical scale models. Comprehensive sets of laboratory measurements in combination with analytical routines were then used to simulate daylight performance for any solar position. Results show increased daylight levels and an improved luminance gradient throughout the year-indicating that lighting energy consumption and cooling energy due to lighting can be substantially reduced with improvements to visual comfort. Future development of the designs may further improve the daylighting performance of these systems.This research was funded by the California Institute for Energy Efficiency (CIEE), a research unit of the University of California. CIEE is a consortium of the CPUC, the CEC, and California utilities including LADWP, SCE, SCG, SMUD, and PG&E. Publication of research results does not imply CIEE endorsement of or agreement with these findings, nor that of any CIEE sponsor. Additional related support was provided by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technologies, Building Systems and Materials Division of the U.S. Department of Energy under Contract No. DEAC03-76SF00098

Energy and Daylight Performance of Angular Selective Glazings

This paper presents the results of a study investigating the energy and daylight performance of anisotropic angular selective glazings. The DOE-2.1E energy simulation program was used to determine the annual cooling, lighting and total electricity use, and peak electric demand. RADIANCE, a lighting simulation program, was used to determine daylight illuminance levels and distribution. We simulated a prototypical commercial office building module located in Blythe, California. We chose three hypothetical conventional windows for comparison: a singlepane tinted window, a double-pane low-E window, and a double-pane spectrally selective window. Daylighting controls were used. No interior shades were modeled in order to isolate the energy effects of the angular selective glazing. Our results show that the energy performance of the prototype angular selective windows is about the same as conventional windows for a 9.14 m (30 ft) deep south-facing perimeter zone with a large-area window in the hot, sunny climate of Blythe. It is theoretically possible to tune the angular selectivity of the glazing to achieve annual cooling energy reductions of 18%, total electricity use reductions of 15%, and peak electric demand reductions of 11% when compared to a conventional glazing with the same solar-optical properties at normal incidence. Angular selective glazings can provide more uniformly distributed daylight, particularly in the area next to the window, which will result in a more visually comfortable work environment.This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Building Technology, State and Community Programs, Office of Building Systems of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098

Singapore’s Zero-Energy Building's daylight monitoring system

A setup to monitor the daylighting performance of different glazing types in Singapore is presented. The glazing is installed in the facade of four dedicated testing chambers in BCAA's Zero Energy Building in Singapore. These test rooms are equipped with sensors that both record illuminances on the work plane, and luminances as seen by occupants. The physical and logical design of the monitoring system is presented. Criteria to assess the daylighting performance are introduced, and initial results of the work in progress are presented

Resilient cooling strategies – A critical review and qualitative assessment

The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous indoor thermal conditions. This study performed a critical review on the state-of-the-art of cooling strategies, with special attention to their performance under heatwaves and power outages. We proposed a definition of resilient cooling and described four criteria for resilience—absorptive capacity, adaptive capacity, restorative capacity, and recovery speed —and used them to qualitatively evaluate the resilience of each strategy. The literature review and qualitative analyses show that to attain resilient cooling, the four resilience criteria should be considered in the design phase of a building or during the planning of retrofits. The building and relevant cooling system characteristics should be considered simultaneously to withstand extreme events. A combination of strategies with different resilience capacities, such as a passive envelope strategy coupled with a low-energy space-cooling solution, may be needed to obtain resilient cooling. Finally, a further direction for a quantitative assessment approach has been pointed out

High-performance commercial building systems

This report summarizes key technical accomplishments resulting from the three year PIER-funded R&D program, ''High Performance Commercial Building Systems'' (HPCBS). The program targets the commercial building sector in California, an end-use sector that accounts for about one-third of all California electricity consumption and an even larger fraction of peak demand, at a cost of over $10B/year. Commercial buildings also have a major impact on occupant health, comfort and productivity. Building design and operations practices that influence energy use are deeply engrained in a fragmented, risk-averse industry that is slow to change. Although California's aggressive standards efforts have resulted in new buildings designed to use less energy than those constructed 20 years ago, the actual savings realized are still well below technical and economic potentials. The broad goal of this program is to develop and deploy a set of energy-saving technologies, strategies, and techniques, and improve processes for designing, commissioning, and operating commercial buildings, while improving health, comfort, and performance of occupants, all in a manner consistent with sound economic investment practices. Results are to be broadly applicable to the commercial sector for different building sizes and types, e.g. offices and schools, for different classes of ownership, both public and private, and for owner-occupied as well as speculative buildings. The program aims to facilitate significant electricity use savings in the California commercial sector by 2015, while assuring that these savings are affordable and promote high quality indoor environments. The five linked technical program elements contain 14 projects with 41 distinct R&D tasks. Collectively they form a comprehensive Research, Development, and Demonstration (RD&D) program with the potential to capture large savings in the commercial building sector, providing significant economic benefits to building owners and health and performance benefits to occupants. At the same time this program can strengthen the growing energy efficiency industry in California by providing new jobs and growth opportunities for companies providing the technology, systems, software, design, and building services to the commercial sector. The broad objectives across all five program elements were: (1) To develop and deploy an integrated set of tools and techniques to support the design and operation of energy-efficient commercial buildings; (2) To develop open software specifications for a building data model that will support the interoperability of these tools throughout the building life-cycle; (3) To create new technology options (hardware and controls) for substantially reducing controllable lighting, envelope, and cooling loads in buildings; (4) To create and implement a new generation of diagnostic techniques so that commissioning and efficient building operations can be accomplished reliably and cost effectively and provide sustained energy savings; (5) To enhance the health, comfort and performance of building occupants. (6) To provide the information technology infrastructure for owners to minimize their energy costs and manage their energy information in a manner that creates added value for their buildings as the commercial sector transitions to an era of deregulated utility markets, distributed generation, and changing business practices. Our ultimate goal is for our R&D effort to have measurable market impact. This requires that the research tasks be carried out with a variety of connections to key market actors or trends so that they are recognized as relevant and useful and can be adopted by expected users. While some of this activity is directly integrated into our research tasks, the handoff from ''market-connected R&D'' to ''field deployment'' is still an art as well as a science and in many areas requires resources and a timeframe well beyond the scope of this PIER research program. The TAGs, PAC and other industry partners have assisted directly in this effort by reviewing and critiquing work to date, and by partnering in activities that advance results toward market impacts. The goals, objectives and key accomplishments of each technical program element and projects are described in the sections that follow. For each project we then summarize the Task Approach, the Outcomes of each task, and our Conclusions and Recommendations. We also provide a list and short summary of each significant research product e.g. report, prototype, software, standard, etc