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Intelligent Middleware Infrastructure Aids Automated Demand Response

Consisting of seven buildings totaling 1 million sq ft, including data-center, office, and laboratory space, the corporate headquarters of NetApp, a provider of storage and data-management solutions, in Sunnyvale, Calif., has an annual utility bill of $7.7 million, 89 percent of which goes for electricity.

With a peak power demand of 7.2 mw, the headquarters required 54 million kwh annually. Cogeneration measures were used to produce 2 mw. Looking to reduce energy consumption, particularly on high-energy-demand days, NetApp reached out to the local utility, Pacific Gas and Electric Co. (PG&E), to take advantage of lucrative incentive-based energy-reduction programs through automated demand response (ADR).

NetApp implemented various reset ranges for all equipment, adding hardware for more accurate control, and changed the space environment to increase equipment utilization. NetApp focused on interoperability, turning to open standards to create interfaces for its disparate building-automation systems, metering systems, power-distribution units, and uninterruptible power supply.

Needing an intelligent middleware infrastructure that would aggregate, normalize, and make available all of the data from the disparate building systems and allow data to pass bidirectionally from the building systems to PG&E's demand-response automation server (DRAS) via Web services, Net-App turned to Richards-Zeta Building Intelligence Inc. and RZ Mediator.

RZ Mediator is an intelligent middleware solution comprised of hardware and software designed and built upon the open-sourced technologies of Linux and Python. The Multi-Protocol Exchange (MPX) integration framework normalizes both Internet and legacy serial-based protocols, allowing for intraprotocol communication; the uniform application of services, such as logging; and the common presentation of information sourced from an array of intelligent machines, such as those found in NetApp's buildings. RZ Mediator also facilitates trending and reporting of ADR events and is used for measurement and verification for ADR-program participation. RZ Mediator includes an intelligence layer that provides custom logic and advanced math between integrated building systems and change-of-value notification to maximize data-management efficiency and the ability to incorporate any application/Web service into locally residing logic and math application.

The benefits of an intelligent middleware solution include system interoperability and the opportunity to develop ADR-technology best practices. By minding the capability gap, an intelligent middleware device brings building systems and enterprise services together through communication, data, integration, and services.

Validation of the ADR measures came on a hot day in August 2007. RZ Mediator, which constantly “listens” for events, was able to consume a pending ADR event when PG&E issued a Stage 3 alert through the DRAS. Instead of the typical “0,” Mediator received a “1” and automatically notified the controls engineer, Dave Shroyer, via e-mail and text message. Feeling confident that the control strategies within all of the building systems were set to take full advantage of the ADR event, Shroyer accepted the event. Upon notification from the DRAS, Mediator triggered NetApp's pre-set control strategies for load reduction, lights were dimmed, and temperature set points were raised. Within 10 min, NetApp was able to automatically reduce peak power by nearly 1 mw (936 kw).

Information and photograph courtesy of Richards-Zeta Building Intelligence Inc.

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