Program Administration

Funded by California Energy Commission's Public Interest Energy Research (PIER) Program

Web-Enabled Automatic Diagnostics

Problem Statement
Several of AEC's subcontractors under the PIER-funded Energy Efficient & Affordable Small Commercial and Residential Buildings Program (PIER Contract # 400-99-011) developed and tested methods to diagnose problems with HVAC system performance. This project will integrate two of these methods into a suite of web-accessible applications:

NIST's air-handling unit diagnostics in accordance APAR; and
Diagnostics for chillers, cooling towers, and pumps developed under prior PIER sponsored research (Project 2.5, Pattern Recognition Based FDD) based on the ENFORMA® HVAC Diagnostics Analyzer.

A potential barrier to widespread use of continuous HVAC system commissioning and diagnostics is the availability of data from the building management systems. To reach the largest customer base possible, we believe that two data access paths need to be pursued. Recent versions of EMSs have features that allow easier access to data. However, legacy EMSs often do not have robust data access, which leads to the concept of using a data acquisition method separate from the EMS. Furthermore, the portion of existing building stock without EMSs or with older EMSs that do not have sufficient data points for diagnostics is very large. AEC will concentrate its efforts on the use of data gathering equipment that is independent of the existing control system. However, receiving certain control signals and other available data from the EMS, also is necessary for the analysis.

Approach
The suite of diagnostic applications will run on a centralized, web-accessible server. Any changes and improvements to the data analysis and diagnostic methods can be implemented quickly and easily at a central location. AEC has successfully field-tested this concept on buildings in California as part of its work in the California Building Energy Initiative. The primary target market for this suite of applications will be buildings with built-up HVAC systems.

The diagnostic applications will be designed for use primarily in an off-line mode. The purpose of the diagnostic applications is to find problems related to energy waste.

To provide the greatest benefit to California, the integrated diagnostic engine developed in this project will be available to any Application Service Provider (ASP) who wishes to incorporate it into its offering. To facilitate licensing this capability to third parties, data transfer interfaces will be developed using XML over HTTP. XML over HTTP uses URIs with specific name/value pairs to invoke methods and processes within the Web Services framework. Once the URI is processed, a well-formatted XML document is returned as a response. To allow quick adoption, we also may provide simple XSLT service to parse the XML and convert it to an HTML document. The advantages of this approach are well understood by software developers, providing easier maintenance and development for both the ASP and diagnostic engine provider.

Each service provider will have their own on-site data collection equipment. This data is transferred to the ASP servers at least daily. Next, the data is transferred to the diagnostic web server for analysis. The results of this analysis are returned to the ASP, and then made available to the users via the World Wide Web in the form of reports or notifications.

Current News:

The Web-based diagnostic engine, which is an alpha-stage development is being field tested at two sites in Colorado, one at a sports club and one at a university library. Both sites involve chiller systems with dual duct AHUs.
Product developers have signed a non-exclusive development agreement with Tridium and the current development work is being tested on the Tridium Niagara platform.
Investigation of using the AHU algorithms for packaged DX systems is underway.
Beta-stage test sites are being sought in California.

Updated August 25, 2004