Status (updated 5/13/2014): Ongoing
Funding sources: Research Grants and CBE Membership
Develop and test an indoor environmental measurement platform with associated sensors and software for real-time evaluation of HVAC system performance. Provide special capabilities suitable for detailed analysis of buildings with underfloor air distribution (UFAD) or displacement ventilation (DV) systems.
This project will also create a toolkit for complying with the new Performance Measurement Protocol (PMP).
Significance to Industry
There is an increased awareness in the building industry that detailed commissioning is an essential part of a successful project process. This is especially true for the new generation of increasingly complex building systems that are emerging to address energy and comfort issues. UFAD and DV systems are two examples of new technologies being widely deployed in commercial office buildings. However, several CBE field studies have shown that UFAD systems are frequently not commissioned adequately and are therefore not being operated in a manner that optimizes potential energy and comfort benefits.
Effectively operating a UFAD system requires measurement of several environmental parameters, including the supply air temperature and airflow rate, the vertical temperature distribution, and the temperature distribution in the underfloor plenum. Parameters for assessing comfort in a UFAD building include the average temperature and temperature gradient in the "occupied zone," relative humidity, air velocity, and radiant temperatures of room surfaces. Typically, building commissioning agents have limited tools for accurately measuring many of these variables in a systematic and efficient manner.
We have developed the mobile measurement cart by adapting a commercially available hand truck, commonly used for moving boxes and other heavy items. The hand truck design was selected because it can be moved freely around a room and takes up a minimum of horizontal space. The cart is configured with the following instrumentation:
Computer: Laptop computer with software visualization and data processing software and a database to store results for further review and analysis.
Stratification profile tree: A series of rapid response thermocouples on a telescoping pole can extend to 13 feet, with thermocouples in increments of 9 or 12 inches, and 4 inches from the floor and ceiling. An additional thermocouple is available for insertion into floor diffusers to measure supply air temperature.
Plenum pressure measurement: An accurate low pressure-measuring transducer for measurement of plenum-to-room differential pressure.
Radiant temperature: Two infrared (IR) temperature detectors oriented to measure ceiling and floor surface temperatures.
In addition to the cart-mounted instrumentation, the system uses up to 70 wireless sensors that may be installed in UFAD floor diffusers. Temperature data from the sensors is transmitted by a self-configuring, radio "mesh" network, and recorded on the laptop on the cart. This data is used in conjunction with the other measurements to evaluate the performance of the system. Data can be displayed in real time as and historical data can be retrieved from the database for analysis.
The cart was employed in the commissioning of the new 52-story New York Times (NYT) headquarters building in New York City. The system combined real time measurements with analysis based on emerging UFAD commissioning procedures while supporting the NYT's desired work flow. CBE fabricated a second version of the cart provided to the NY Times, which is now being used for new CBE field studies in UFAD buildings in a research effort sponsored by the U.S. General Services Administration.
Publications and Reports
Heinzerling, D., S. Schiavon, T. Webster and E. Arens. 2013. Indoor environmental quality models: Literature review and a proposed weighting and classification scheme. Building and Environment.
Heinzerling, D., T. Webster, S. Schiavon, G. Anwar and D. Dickerhoff. 2013. A prototype toolkit for evaluating indoor environmental quality in commercial buildings. CBE Internal Report. May.
Webster, T., C. Benedek and F. Bauman. 2008. CBE UFAD cost analysis tool: Life cycle cost model, issues and assumptions. Prepared for U.S. General Services Administration (GSA) Public Buildings Research Program. Contract No: GS-00P-02-CYC-0071. June.
Lehrer, D., 2007. Delivering buildings that work: Commissioning at the New York Times. Centerline, Center for the Built Environment (CBE), University of California, Berkeley, pp 3-6, July. (PDF)
Webster, T., et. al., 2005. Mobile Wireless building evaluation toolkit, Research Overview, Berkeley, CA. October. (PDF)
Hughes, G. and M. English, 2007. Underfloor Air Distribution in a Commercial High Rise: The New York Times Headquarters. Proceedings, National Conference on Building Commissioning, May 2007. (PDF) External Link