Buildings that Change Their Behavior
by Arthur F. Pease
The article appears as part of the magazine at
From fast food outlets to soaring office towers, buildings come in all shapes and sizes. But two things most of them have in common are a voracious appetite for energy and a huge potential for efficiency improvement. In fact, according to U.S. and German government statistics, residential and commercial buildings consume 40 percent of primary energy worldwide and are responsible for producing 21 percent of total CO2 emissions.
How much of this energy could be saved? “Depending on the building, anywhere between 24 and 50 percent,” says Thomas Grünewald, head of Siemens Corporate Technology’s High Performance Building Lighthouse project and an authority on energy-saving technologies for buildings and cities. Statistics from Site Controls, a U.S. company recently acquired by Siemens Building Technologies that specializes in energy management for large chains of stores, bear him out. In spite of the rising cost of electricity, the company’s customers have seen their electric bills drop between 15 and 30 percent. With commercial buildings accounting for 46 percent of all the energy consumed by buildings in the U.S., Site Control’s potential long-term effect on energy demand could be enormous.
French Fries and an Energy Analysis
Working along similar lines, Reno, Nevada-based LoadIQ, a startup funded by the Siemens Technology-to-Business Center in Berkeley, California, has come up with a technology that could cut the electric bills of the U.S.’s 70,000 fast food restaurants by 20 percent. After a training phase, the technology uses advanced signal processing to associate changes in power consumption reaching the restaurant’s electric meter with individual devices, such as ovens, fryers, and refrigeration units. “The system looks at the change in power each time an appliance turns on or off,” explains LoadIQ CEO Hampden Kuhns. “Each change is characterized by a unique signature. For instance, a 50W incandescent light and a 50W fluorescent light have completely different signatures, since one has an inductive load and the other is perfectly resistant.” Nevertheless, this can be remarkably complicated because many appliances have a variety of cycles. “But we have found ways of isolating each cycle and then recombining them as a signature for a single device,” says Kuhn. “This can lead to identification of distinct activities within a device, such as an energy-intensive hot water heating cycle in a dishwasher.”
At regular intervals, information regarding a device’s actual energy demand is compared to its publicized demand and to the electrical demand of competing devices. Finally, if significant discrepancies are identified, LoadIQ technology generates a report for the owner recommending that the device be serviced or replaced. The winner of a 2009 National Science Foundation (NSF) Small Business Innovative Research (SBIR) award, LoadIQ is about to begin testing its technology in small commercial settings.
Shaving Demand for Peaker Plants
The need to enhance efficiency and reduce electric bills is not limited to individual businesses and consumers. Indeed, in many countries, the stability of entire electricity generation and distribution networks is at stake. If electrical demand approaches the limit of capacity, brown outs (a drop in voltage) or rolling blackouts may occur. To avoid such disruptions, power companies generally switch on so-called “peak power” plants. But because such plants are only rarely activated, they are extremely expensive to operate. The result is a sudden spike in the price of electricity that can amount to several hundred percent per kWh. “In the U.S., ten percent of the entire energy generation and distribution infrastructure is there to provide peaking power that is used only one percent of the time,” explains Dr. George Lo, a specialist in automation and a top researcher at Siemens Corporate Technology in Princeton, New Jersey. In view of this, utilities clearly want to avoid peaks because by doing so they defer the cost of investing in new peaking plants. “Nevertheless,” says Lo, “if we continue down a business-as-usual path, over the next ten years, the U.S. will have to build as many as 1,900 additional peaker plants in order to keep up with increasing demand.”
But as companies across the U.S. and around the world develop their own responses to sudden peaks in electricity prices, they are beginning to shine light on how the entire problem of peak demand can be managed. The Site Controls IT-based building automation platform (see page XX), for instance, not only reduces everyday electricity demand, but, thanks to its ability to respond to market signals from a utility, holds the potential for responding to variations in electricity prices on a 24/7 basis. “If significant numbers of buildings were to operate on this basis, the collective effect would be the elimination of peaks and an automatic real-time leveling of electrical loads,” says Lo.
A Box that Controls a Building
Figuring out exactly how to achieve that, particularly in very large, multi-use buildings, is one of the ambitious goals of energy efficiency experts at Sutardja Dai Hall, the newest research facility on the campus of the University of California, Berkeley (UCB). Outfitted with a Siemens Apogee automation system, Sutardja Dai functions as a test bed for building-to-grid technologies such as automated demand response (ADR). In order to ensure that a building’s response to changing electricity prices is both automated and intelligent, Siemens is working with UCB to test what it calls a “Smart Energy Box” at Sutardja Dai. “The idea is that when a peak is predicted, the Box goes through a library of scenarios that range from reduced cooling and lighting in non-critical areas to a finely-tuned, distributed response that can include almost anything that’s plugged into a wall socket. It takes expected prices and weather conditions into account, including where the sun will be in relation to the building during a DR event,” explains Lo, “Finally, it chooses the best scenario and implements it.”
To achieve such a response without inconveniencing building occupants can be a tricky task. It calls for the ability to learn from the schedules, habits and energy priorities of different departments within a building. Excluding those areas of a building that are off limits in terms of power adjustments because of vital or very high-value functions, the Energy Box minimizes inconvenience by maximizing the distribution of its demand response over as many systems as possible.
Essential to this entire process is a protocol that allows building automation systems to read ADR signals from utilities. Developed by the Lawrence Berkeley National Laboratory (LBNL) and recently adopted by the U.S. Department of Energy, the protocol is rapidly moving toward worldwide acceptance and may well become the standard for building-to-grid communications. “This is extremely important,” says Prof. David M. Auslander of the UCB Mechanical Engineering Department and a key advocate of the university’s participation in this technology. “LBNL is testing ADR at several hundred facilities. And Sutardja Dai Hall is one of them – thanks to the Energy Box. The issue here is that the wholesale price of electricity varies from minute to minute, but its retail price often looks flat. The Energy Box could change that – essentially transforming electricity from a fixed part of overhead to an expense that can be actively managed.”
Adds Sutardja Dai Building Manager Domenico Caramagno, “Thousands of buildings could benefit from this box, not only to shed load during DR events and thus benefit from cash incentives from utilities, but to maximize their energy savings around the clock. That is the direction we are heading.”