High-Performance Commercial Building Systems
The California Energy Commission's Public Interest Energy Research (PIER) program has funded a three-year, $9 million research initiative to reduce the energy use of commercial buildings (see EETD News, Vol. 2, No. 3, p. 1 for announcement.)
Commercial buildings use one-third of all electricity consumed in California. EETD research suggests that the energy use of these buildings can be reduced by 30 to 50%, but capturing these savings requires an integrated program of research, development, demonstration, and market transformation to bring the necessary technologies and practices into common use. Having a roadmap for the program is particularly important in view of the fact that in the buildings sector, with its complex relationships among builders, vendors, designers, and contractors, new innovations can take 10 to 20 years to diffuse into the market.
Berkeley Lab's EET Division is the prime contractor for the PIER-funded High-Performance Commercial Buildings Program (HPCBS), leading the work of about a dozen public and private sector partners. The program's goals are to reduce electricity use in the California commercial sector by 22% by 2015, while assuring that these savings are affordable, and to promote high-quality indoor environments. These energy savings would amount to approximately 24,000 GWh (gigawatt-hours) per year and would save ratepayers $2.4 billion per year. Additionally, the energy savings would benefit the global environment by reducing carbon emissions by 2,260,000 tons per year.
The project is divided into five technical elements (life-cycle tools; lighting, envelope and daylighting; low-energy cooling; integrated commissioning and diagnostics; and indoor environmental quality.)
These articles summarize the goals of the five elements of the research and some recent milestones.
The element's goal is to develop integrated information management technologies to assist in improving commercial building performance. The problem it seeks to solve is the fragmentation of information flow among the designers, builders, and operational managers of buildings, who generally don't communicate information such as design intent and expected performance of building systems with one another. The resulting loss of information from design to construction and then to the operational phases of a building's life increases its energy bills, reduces occupant comfort, and can shorten the useful life of the building.
Technologies that are missing from the design-build-operate life cycle of buildings, and that we are developing, include standard performance metrics and benchmarking tools, methods for retrofit performance analysis, and protocols for exchanging data among building software programs.
Team members in this element (EETD, MIT, Silicon Energy, and Honeywell) are developing and expanding a number of tools or protocols: for performance metrics and benchmarking (Cal-ARCH); for improved analysis of retrofitting buildings (Metracker and RESEM), and for interoperable building simulation software (activities of the International Alliance for Interoperability (IAI) and its Industry Foundation Classes (IFCs) standard).
The Cal-ARCH, Metracker, and RESEM programs are all in development; software specifications for each tool have been completed. Team members have been working with the IAI to develop IFC protocols for HVAC systems simulation—with this tool, software programs from different manufacturers will be able to exchange data easily with each other.
A benchmarking project is underway, in which energy data collected from school buildings and a college campus are providing the basis for a common set of benchmarks to measure and rate the energy performance of commercial buildings. As the project continues next year, data will be collected from a larger sample of school buildings. The U.S. Environmental Protection Agency has used this data to modify its energy benchmarking methodology, and the state of California has found it useful in the planning of the Governor's Energy Challenge.
For more information, contact:
- Mary Ann Piette
- (510) 486-6286; fax (510) 486-4089
Lighting, Building Envelope, and Daylighting
High cost and poor performance have limited market penetration of controllable lighting and building envelope systems. Lighting and envelope systems, often manufactured by different vendors, cannot communicate with one another, preventing their optimization for energy efficiency and occupant comfort.
The goal of this element is to develop an integrated building equipment communications system (IBECS) that will provide Internet-based control of lighting, daylighting, and envelope systems. The project team (EETD, Vistron, and MB Associates) is developing lighting controls: a networking system combining lighting controls and envelope systems, such as motor-controlled blinds or electrochromic windows; and network software to commission, maintain, and diagnose problems within these building subsystems.
Prototypes for a number of the deliverable products of this element have been completed. They include an IBECS ballast network interface switch for controlling fluorescent lighting, and an IBECS-controllable, Title 24-compliant wall switch (see drawing). The IBECS ballast network interface has been successfully tested in an office at Berkeley Lab. We are beginning the development of an IBECS-ready occupancy sensor, that will also be able to measure other variables such as lighting level and temperature, and transmit this information over the network.
A test-bed demonstration of a sensor-controlled electrochromic window installation in an office (see EETD News, Vol. 2, No. 1, p. 1) has shown that this technology can be used to improve energy efficiency and occupant comfort, although additional testing and refinement of the technology will be necessary. Earlier tests of an actively-controlled Venetian blind daylighting system for office windows also showed great promise.
We are now developing plans to launch a multi-year engineering field test of electrochromic window systems in commercial buildings, and to develop the control technology needed for whole-building, active load management. We are also developing an IBECS-ready control system for the Venetian blind daylighting technology.
For more information, contact:
- Francis Rubinstein
- (510) 486-4096; fax (510) 486-4089
Conventional cooling systems are energy-intensive, contributing substantially (14%) to peak electricity demand in California. That demand is increasing as population grows in California's hotter inland areas. A number of compressorless cooling-system technologies can increase cooling efficiency, and methods are available to reduce cooling losses in the distribution system. The goal of this element is to significantly reduce cooling energy use and peak demand in commercial buildings. Other goals include improving health and productivity through systems that improve indoor air quality and comfort.
The project team partners (EETD, UC San Diego, Ove Arup and Partners, and Flack + Kurtz) are identifying and evaluating combinations of low-energy cooling technologies, and developing computer simulation models for the design of these systems. Other components of the work include evaluating the energy losses present in commercial cooling distribution systems (e.g., duct leakage), and developing new design tools and guides. Ultimately the goal is to incorporate widespread use of innovative cooling designs into the Title 24 building standard.
There has been a significant and growing interest in natural ventilation for commercial buildings. We have used the EnergyPlus simulation program to provide input to the design of a new, naturally ventilated Federal office building for San Francisco. The team members of this element have also been reviewing synergistic combinations of compressorless cooling technologies, energy-efficient space-cooling methods and distribution systems, and assessing the energy-savings potential of these technologies for the 16 climate zones of California, and various building types. More than 10,000 computer simulations of these combinations have been run.
Work is continuing to measure the leakage of energy from the duct systems of commercial buildings, and to develop metrics and diagnostics for these systems. We are also working to improve the simulation of ventilation and its effect on cooling. This work will result in a substantial improvement of EnergyPlus' ability to accurately model both mechanical and natural ventilation.
For more information, contact:
- Philip Haves
- (510) 486-6212; fax (510) 486-4089
Integrated Commissioning and Diagnostics
Once built, many commercial buildings do not perform as well as expected—using more energy, and causing occupant discomfort. An EETD study found that in a sample of 60 buildings, half had control problems and 40 percent had HVAC equipment problems. Other research has demonstrated that the proper commissioning of buildings (checking that all systems are working before a new building is occupied) can avoid these problems.
The goal of this element is to make commissioning of new commercial buildings a standard practice, and to make "continuous commissioning" (the tuning of existing buildings) into a widely used practice. The element's project team consists of Texas A&M, EETD, PECI, MIT, UC Berkeley, University of Nebraska, Ove Arup, Flack + Kurtz, Silicon Energy, and AEC. A large variety of projects is underway to improve the commissioning and monitoring of new and existing buildings. Team members are building a library of functional test procedures, together with manual tools and guides, that building operators and contractors can use to commission lighting, HVAC and other building systems. Another result of the work will be a guide to commissioning for building designers—many designers currently do not document their design intent or provide the owner with performance specifications. The guide will provide information on integrating commissioning into the design and construction process.
Software tools to improve the diagnosis of problems in building systems are also under development as part of this element. These will include fault-detection procedures, using energy management and control systems to monitor performance, and systems to get Internet-based feedback from building occupants on problems they report.
Other tasks under this element include studying the persistence of energy savings in new buildings that have been commissioned, developing technology to monitor major electrical loads within buildings, and developing tune-up procedures for use in commissioning existing buildings.
Among some of the early results of this element:
Texas A&M completed an analysis of the multi-year energy savings from "retro-commissioning" 10 buildings, finding that savings persisted well, degrading by only a few percent per year. This demonstrates that commissioning a building and tuning its energy use, even after it has been occupied and used, is a viable energy-saving strategy.
EETD and UC Berkeley worked with the General Services Administration and the City of Oakland to test and evaluate diagnostic techniques and demand-shedding strategies in several large buildings. EETD received funds from GSA for the Web-based remote-monitoring GEMnet (GSA Energy and Maintenance Network), a significant deployment opportunity for this program's research results. UC Berkeley continues to work with GSA to examine maintenance and complaint logs, and test a web-based occupant feedback system.
For more information, contact:
- David Claridge
- (979) 845-1280; fax (979) 862-2418
Indoor Environmental Quality
In this element, we are investigating and demonstrating how the application of building science and ventilation engineering can lead to simultaneous building energy savings and indoor environmental quality performance improvements. This project focuses on developing and testing a concept for high-performance relocatable classrooms (RCs). RCs, otherwise known as "School Portables," or "Modular Classrooms," are very common in California. They provide school districts with quick and convenient means of adding or replacing classrooms, and can be moved around, reducing unnecessary classroom construction. An estimated 75,000 to 95,000 are currently in use in California school. The state of California mandates that at least 20% of new classrooms be RCs, and 6,000 to 8,000 single units are being placed annually.
We are in the process of evaluating the benefits of a novel RC ventilation system, and also of selecting construction materials that emit fewer indoor pollutants. We will construct and study four RCs; a pair sited and operated as classrooms in each of two California school districts with different climatic conditions. The basic specifications for the classrooms will include energy-efficient lighting, building envelope, and window enhancements. One task is to test a high-performance ventilation and air-conditioning system, the Indirect-Direct Evaporative Cooler (IDEC), suitable for warm dry climate zones of California. In these climates, IDEC offers potential cooling energy savings of about 70% compared to the standard (10 SEER) air conditioner used in RCs.
In addition to energy savings, the IDEC provides a continuous flow of outside air that will improve the indoor air quality of the RCs. For heating, an energy-efficient, natural gas-powered hydronic loop will be integrated into the IDEC ducting system. For test purposes, each RC will be equipped with both a standard HVAC and an IDEC/hydronic heat system. The HVAC system being operated will be alternated on a weekly basis with the unused system sealed and turned off. Indoor air quality (carbon dioxide, volatile organic compounds (VOCs), size-resolved airborne particle counts), thermal comfort, noise, and energy use will be monitored continuously and the ensuing data will analyzed to compare indoor environmental quality and energy use under the two HVAC system regimes.
A second task focuses on identifying the RC materials that are the major VOC sources through chamber measurements. Two of the field test RCs, one at each school, will be constructed using alternative materials selected for lower VOC emissions. The project also includes an effort to develop, test, and refine computer models of RC energy performance in California. Data from the field study will be used to validate the computer simulations and upgrade inputs to the model. Energy and cost-benefit projections will be made for different California climate zones.
We have received the enthusiastic cooperation of school districts and a manufacturer of RCs, and we are exchanging data with a number of groups on indoor air quality in schools.
For more information, contact:
- Michael Apte
- (510) 486-4669; fax (510) 486-6658
For more information on each of the commercial building projects, see High Performance Commercial Building Systems.
This research is supported by the California Energy Commission Public Interest Energy Research Program, and the U.S. Department of Energy.