Hologram PV windows

A novel approach to solar PV has been quietly hatching in Tucson for a number of years. I’ve been on their trail since early ’98, but until very recently they were in strict stealth-mode, and it was impossible to get a handle on what they were doing. (It was refreshing to see a startup that understood the benefits of laying low until they have something to show.)

TerraSun’s patent issued quietly in March ’99 (# 5,877,874), and then in mid May of this year, they did a press release and launched an effort to raise money and identify potential customers and strategic partners (suppliers and sales channels). The company has been funded up to now by part-owner Apogee Enterprises (nasdaq APOG), an $800 million major manufacturer of architectural window products (

Their PV technology uses holographic optics to concentrate light onto standard silicon cells. Imagine a multi-layer window pane with solar cells arrayed across it in long bands, leaving clear spaces inbetween. If a band of cells is 1″ wide, then the clear space would be from 1″ to 4″ wide. A holographic film, sandwiched between layers of glass, directs the incoming light into the solar cells. Solar concentration ratios of 1.5 have already been demonstrated, and the company believes they can reach ratios of 4-5.

There are several implications. One, as with any concentration scheme, less area of silicon is needed, which presumably lowers cost. Two, the wavelengths of light directed into the cell can be optimized. Three, the window remains transparent, allowing the passage of light, ideal, for example, for skylights. Four, the wavelengths of this transmitted light can be tuned, for example to reject heat. TerraSun has coined a term “Power Window” to describe a product which produces on peak electricity, while allowing the passage of daylight. (The company estimates this approach will be competitive with the various semi-transparent thin-film PV approaches that others are developing.)

With the growing interest in BIPV (building integrated PV), and energy efficiency in general (e.g. low emissivity coatings for windows), TerraSun expects to exploit huge opportunities not only in PV, but eventually in other applications of holographic optics as well. They see energy as perhaps only the first area of application for holographic optics, which is the company’s real strength. (Using holograms as optical devices is a relatively new and little-known idea. In effect, holograms can be made to act as lenses, mirrors, filters, etc., processing light instead of just recording images.)

The company’s website is Much more information is available from the company, in particular, a confidential business plan.

Glenn Rosenberg, 520-512-1995

LBNL Building Technology

(One of a series of notes detailing results of recent visits to
Lawrence Berkeley National Labs – LBNL)

Building Technology Dept.

Commercial Building Systems, Simulation, Windows & Daylighting, Lighting, and Applications
LBNL has one of the largest US building RD&D activities; active since 1976 in this field, approx. $18M per year in funding currently; with about $12M from DOE and remainder from other sources, addressing most major aspects of building energy use, including hardware, systems, software, indoor environmental issues.
Stephen Selkowitz, Dept. Head, 510-486-5064


Diagnostics for Building Operation and Commissioning
Commercial buildings alone consume about 15% of all energy at a cost of $85 billion annually. Half of this consumption is wasted, compared to what is cost-effectively achievable. To realize these savings requires a careful examination of the process by which buildings are designed, built, commissioned, and operated, using a life-cycle approach.

A multi-year project is underway to develop and apply technology to improve building operation and maintenance. In a collaborative effort among researchers, building owners, utilities and private industry, an interdisciplinary team has been gathered to:
– Assess the current state of performance technology
– Develop an appropriate information gathering and diagnosis capability
– Test this new diagnostic system in real buildings


Information Monitoring and Diagnostic System (IMDS)
160 Sansome, San Francisco

The first IMDS has been installed and is now operating in an 18 story 100,000 sq ft, class A, San Francisco office building, built in 1964.

The IMDS includes 56 sensors, 34 calculated fields (for a total of 90 monitored data points), computer-based communications, data archival and retrieval capabilities, diagnostic information processing, data visualization, and other components that meet the needs expressed by building owners and property management companies. Existing proven hardware and systems were used, and the focus is on obtaining detailed accurate technical data (e.g. sufficient for calculations for a performance contract). Note this is a passive system, performing measurements only, and not control of equipment. A detailed specification is to be published.

This system implements a top-down approach, with diagnostic and information visualization algorithms, at three levels.
– Level I diagnoses whole-building performance at the aggregate level,
comparing to other buildings with similar energy services.
– Level II examines major end-use systems, and
– Level III focuses on major subsystems.

Savings opportunities of 10% were identified in the first four months. Life cycle cost issues have come into play, for example, improper rapid cycling of equipment. The active participation of the building’s innovative owner and operators should help publicize the effort and influence others in the industry. More recent findings suggest that the IMDS has proven extremely useful to the on-site building operators, helping them to improve control of the entire building.

Project Team Leader: Mary Ann Piette, 510-486-6286,
The project homepage:

“Development and Testing of an Information Monitoring and Diagnostic System for Large Commercial Buildings,” (paper presented at the ACEEE Summer Study on Energy Efficiency in Buildings, August 1998).

There is a detailed “Virtual Tour” at:
A project overview appears at: (


Building Life-Cycle Information Support System (BLISS)

BLISS is intended to provide a distributed computing environment for managing, archiving, and providing access to the wide variety of data and information that is generated across the complete life-cycle of a building project.

— > Identify Contraints/Opportunities — >
** Design — > Construction — > Commissioning — >
Monitoring — > Operations/Maintenance — >
Retrofits/Use changes — >
Re-evaluate Opportunities — > **

BLISS requires standardization in both a common building database model and in the mechanisms for transferring this information between tools.

The project has three major elements: (1) to specify the distributed software architecture, (2) to develop a life-cycle building model database schema, and (3) to develop a mechanism to capture and update “design intent” throughout the life cycle. The distributed systems architecture describes how various software components communicate, and the building model schema specifies the structure and semantics of the database (e.g. how performance metrics are defined and represented quantitatively).

BLISS is being developed within the evolving software specification from the International Alliance for Interoperability (IAI). The IAI is a non-profit alliance of the building industry with six international member chapters. Its mission is to integrate the industry by specifying Industry Foundation Classes (IFCs) as a universal language to improve communication, productivity, delivery time, cost, and quality throughout the building life cycle.

Currently, Metracker is a tool being developed to help capture design intent via a number of performance metrics and then track changes in those metrics over the life of the building. The data schema is built on the IAI building data model. It is being tested on a new building in Oakland CA.
Contact Rob Hitchcock, 510-486-4154,


Remote Building Monitoring and Operations(RBMO)

A prototype system has been developed which permits remote monitoring and control of multiple commercial buildings across the Internet from a single control center. Such a system would be used by owner/operators of multiple buildings, such a school districts, governments, universities, large retailers, utility companies, building management firms, etc. Average savings estimated at 15% would come from reducing energy waste from equipment that runs when it does not need to, set point optimizations, and correcting operations and control deficiencies.

The project was initiated as a demonstration of the use of internet protocols and open systems for building monitoring, permitting integration of equipment from multiple vendors. It addresses similar IT issues of authentication, access-security, etc., which arise in a major Lab program on sharing scientific instrumentation over the internet.

The project includes the following components.

An Internet-to-building-EMCS (Energy Management Control System) gateway which speaks CORBA (Common Object Request Broker Architecture) protocol atop TCP/IP on the Internet side and either (preferably) BACnet atop TCP/IP, or a proprietary EMCS communications protocol, to the building EMCS.

Development of applications-level object specifications for HVAC objects, e.g., chillers.

A remote building monitoring and control center which will provide data visualization, database management, building energy simulation, and energy usage analysis tools.

Deployment and testing of the system in multiple buildings with diverse types of EMCS systems. Our goal is to assess scalability of the system to large numbers of buildings, both in terms of performance and accommodating heterogeneity of control systems and HVAC systems.

Remote control of HVAC systems – this awaits the availability of a secure CORBA implementation.
Frank Olken 510-486-5891


Simulation Research

The Building Energy Simulation User News is a quarterly newsletter for the DOE-2, BLAST, SPARK, EnergyPlus and GenOpt programs. Sent without charge, the newsletter prints documentation updates, bug fixes, inside tips on using the programs more effectively, and articles of special interest to program users. The winter issue features a cumulative index of all articles ever printed. Current issues are available electronically (below). All issues are available via regular mail, by request.

To subscribe or to request a back issue, contact: Kathy Ellington,

DOE-2 is a computer program for the design of energy-efficient buildings. Developed for DOE, DOE-2 calculates the hourly energy use and energy cost of a commercial or residential building given information about the building’s climate, construction, operation, utility rate schedule, and heating, ventilating, and air-conditioning (HVAC) equipment. A new version, DOE-2.2, includes an integrated SYSTEMS-PLANT program based on circulation loops with tracking of temperatures and flows, luminaire/lamp modeling of lighting systems, a window-blind thermal/daylighting model, input value defaulting using expressions, and expanded building component libraries.

EnergyPlus – A new-generation building energy simulation program based on DOE-2 and BLAST, with numerous added capabilities. Developed by the Simulation Research Group, the Building Systems Laboratory at the University of Illinois, the U.S. Army Construction Engineering Research Lab, and DOE.

GenOpt – A tool for multi-dimensional optimization of an objective function that is computed by a simulation program. This project at LBNL is sponsored by the Swiss Academy of Engineering Sciences, the Swiss National Energy Fund, the Swiss National Science Foundation, and DOE.

SPARK [Simulation Problem Analysis and Research Kernel]
A program that allows users to quickly build models of complex physical processes by connecting calculation modules from a library.

BDA: Building Design Advisor – A computer program that supports the concurrent, integrated use of multiple simulation tools and databases, through a single, object-based representation of building components and systems. Based on a comprehensive design theory, the BDA acts as a data manager and process controller, allowing building designers to benefit from the capabilities of multiple analysis and visualization tools throughout the building design process. The BDA has a simple Graphical User Interface that is based on two main elements, the Building Browser and the Decision Desktop.

International Alliance for Interoperability (IAI) – With international partners, develop Industry Foundation Classes(IFC) and an integrated building information model for describing buildings. Develop methods for allowing applications, such as CAD and energy analysis, to interoperate with the information model. Interoperability will allow diverse building drawing and simulation tools to share the same building description and to exchange results, thus simplifying building design, construction and operation.

RESFEN – A PC-based computer program (using DOE-2 as the simulation engine) for calculating the heating and cooling energy performance and cost of residential fenestration systems. RESFEN is free on a CD.


Windows & Daylighting
Stephen Selkowitz 510-486-5064

– > Glazing Materials Research – Low-Emittance and Solar Control; Static spectral filters; Deposition Processes

– > Characterization facilities/optical lab for in-house research, manufacturers, and to support product rating and related standards activities.

– > The Optical Data Library provides glazing layer (peer-reviewed) optical data for over 800 commercially available products; this data is used with the WINDOW and Optics software.

– > New Materials: track of new materials R&D around the world–strong ties to IEA.

– > Manage the DOE Electrochromic Initiative – 2 labs, 4 manufacturers
Electrochromics or “smart windows” have the potential for becoming an important element in building load management due to their ability to control perimeter cooling loads and lighting loads, both of which are major elements of building peak demand. Occupant control of window shading systems is notoriously unreliable. A smart window whose solar heat gain coefficient can be modulated over a 5:1 range provides a significant new opportunity. While coating development work continues at LBNL and with industry partners, a German product is being purchased by LBNL to test in an office building in Oakland, with a focus on control integration and load management issues.

– > Advanced Systems development, testing, evaluation

– > Window Properties – determining the thermal and optical performance of window systems

– > Daylighting – LBNL has recently recieved substantial funding from California utilities to help convert RADIANCE, a lighting and daylighting research tool that is highly accurate but hard to use, to a desktop environment design tool with a user friendly interface and link to CAD software. A first version will be released in 1999; improved version with additional capabilities in 2000.

– > Residential performance – support Energy Star program; Annual Energy Ratings

– > Commercial Glazing Performance- ramping up R&D in this area, beginning with development of a design guide for architects and engineers. Later will be looking at advanced facade systems and their role in intelligent buildings. Innovative building skins are seen as not only energy savers but as building features that enhance the quality of the indoor space.


Lighting Research

The Lighting Research Group researches and develops fixtures, controls, and software which employ and promote energy efficient lighting. The group is primarily funded by DOE, although some funding is provided by industry for specific projects. The group is recognized as one of the main players in the lighting industry, as both technology developers and as observers/influencers. As such they have an indepth awareness of technological developments, issues and trends in the industry.

Research projects include sources, controls, fixture design, and human factors. Software for lighting design is a major R&D area. The test lab has the equipment which is essential for testing and designing energy efficient lighting fixtures, including a goniometer, integrating sphere, and spectro-radiometer for measuring light output. There is also an electric power analyzer for testing power and power quality of light sources.

The lab has in-house and collaborative work in new kinds of light sources that are being developed — solid state, electroluminescent, white LED, and organic liquids.

Their work to design the (non-halogen) compact fluorescent torchiere has led to the commercial availability on a wide scale of these much safer and more efficient lamps. Several universities did free exchange programs for dormitory residents, and now some utilities are doing it for their customers.
(see website for more details:

Of interest to utilities, compact fluorescent bulbs (CFL) are growing in popularity, but there are issues about price, quality, and longevity. Some imports have low prices, but don’t last as long as they should. To deal with this, some utilities are specifying an unecessarily high number of life hours. Specifications need to incorporate the issue of how often lights are turned off and on, but current testing procedures don’t deal with this effectively. LBL is proposing a new approach to life testing, but lacks the funding to demonstrate it.

“Bi-level” light switching is cost effective, and it is now in the building code for the state of California. (two switches–one controls 1/3 of the lighting in a room, and the other controls the remaining 2/3). Other effective measures are photosensors (for daylighting) and occupancy sensors. But it is important to solve the right problem. Hotels got little benefit from occupancy sensors, because guests rarely leave lights on when they’re out of the room. The biggest waste was found to come from bathroom lights left blazing as a night light — providing a dimmed setting would work better.

Recently, LBL combined low-glare, lower level ambient lighting with custom designed task light fixtures, in a US Post Office sorting facility. Occupancy sensors turned the task light on only when the clerk was present. Task light levels were improved while overall energy was reduced by 70%.


Lighting Software

RADIANCE – A suite of programs for the analysis and visualization of lighting in design. Input files specify the scene geometry, materials, luminaires, time, date and sky conditions (for daylight calculations). Calculated values include spectral radiance (ie. luminance + color), irradiance (illuminance + color) and glare indices. Simulation results may be displayed as color images, numerical values and contour plots. The primary advantage of Radiance over simpler lighting calculation and rendering tools is that there are no limitations on the geometry or the materials that may be simulated. Radiance is used by architects and engineers to predict illumination, visual quality and appearance of innovative design spaces, and by researchers to evaluate new lighting and daylighting technologies. (for UNIX)

(Advanced Daylighting and Electric Lighting Integrated New Environment)
ADELINE is an integrated lighting design computer tool developed by an international research team within the framework of the International Energy Agency (IEA) Solar Heating and Cooling Programme Task 12. It provides architects and engineers with accurate information about the behaviour and the performance of indoor lighting systems. Both natural and electrical lighting problems can be solved, in simple rooms or the most complex spaces. ADELINE produces reliable lighting design results by processing a variety of data (including:geometric, photometric, climatic, optic and human response) to perform light simulations and to produce comprehensive numeric and graphic information. (for PC)

SUPERLITE 2.0 is a lighting analysis program designed to predict interior illuminance in complex building spaces due to daylight and electric lighting systems. SUPERLITE enables a user to model interior daylight levels for any sun and sky condition in spaces having windows, skylights or other standard fenestration systems.

LBL Lighting publications are available (some can be downloaded) at:

Steve Johnson 510-486-4274


Home Energy Saver

The Home Energy Saver(HES) website, announced in March ’99, brings advanced building simulation software to an interactive website to help consumers identify the technologies that will save them the most energy and money.

The Home Energy Saver quickly computes a home’s energy use on-line based on methods developed at LBNL. By changing one or more features of the modeled home, users can estimate how much energy and money can be saved and how much pollution prevented by implementing energy-efficiency improvements. All end uses (heating, cooling, major appliances, lighting, and miscellaneous uses) are included.

The Home Energy Saver’s Energy Advisor calculates energy use and savings opportunities, based on a detailed description of the home provided by the user. Users can begin the process by simply entering their zip code, and in turn receive instant initial estimates. By providing more information about the home the user will receive increasingly customized results along with energy-saving upgrade recommendations.

Developed for the ENERGY STAR Program (EPA and DOE).

The HES Mission Statement ( ) explains the way the program seeks to work with and support private-sector vendors, by complementing their efforts, not competing with them.

Nor is it intended to compete with private vendors of web-based software who seek revenues from utilities who license their products. Nevertheless, utility partnerships with HES are still possible, and indeed some have already begun.

Contact: Rich Brown, 510-486-5896,