Pictures of the Future      Fall 2008

Smart Homes and Cities

Centralized management of building systems such as lighting and climate control results in more efficient operation and reduced energy use. Proof is offered by numerous buildings running on Siemens automation systems. Even greater savings would be realized through the implementation of intelligent sensor networks that would connect the dots from smart homes to smart cities.

In 2002, the European Union issued a directive to increase the energy efficiency of buildings. The directive calls for the Europe-wide certification of buildings and an "energy certificate" to document energy consumption. In Germany, this directive was incorporated into national law on July 1, 2008. The objective is to achieve an 18 % reduction in national energy consumption by 2020, as well as to increase the portion of renewable energy to 14 %. In addition, the European directive defines requirements for heating, ventilation and air conditioning systems—HVAC (see Pictures of the Future, Spring 2008, Building Automation)—that, along with thermal insulation of buildings, play a major role in saving energy.

In the spring of 2008, the European Building Automation and Controls Association (eu.bac), which sets criteria for the energy efficiency of products, certified 27 electronic individual zone controllers made by 15 firms, including Siemens, according to European standard EN 15500. These can, for example, control heating radiators, cooling ceilings, and electric heating systems. Thanks to their appreciably greater precision, these certified controllers save a great deal of energy. "Studies have shown that reducing control deviations from 2 °C to 0.1 °C can result in energy savings of up to 14 %," explains Ulrich Wirth, chairman of the European Committee for Standardization’s Technical Committee for Building Automation, Controls and Building Management and an expert in building automation products and systems in the Siemens Building Technologies Division (BT), based in Zug, Switzerland.

Additional potential energy savings result when optimized HVAC sensors and open- and closed-loop control systems are appropriately combined with lighting systems, blinds, and hot water systems. "This can increase the energy efficiency of buildings by as much as 30 %," adds Wirth.

Exemplary implementations of this interplay include large, new building complexes such as the Mövenpick Hotel in the Europa Quarter in Frankfurt, Germany, and Sihlcity in Zurich, Switzerland. This new 100,000 m² shopping, residential, and leisure center, which opened its doors in March 2007, was built on the grounds of the former Sihl paper factory.

"In Sihlcity, we installed our Designo management system, which takes over energy management for the entire building complex and controls all of the building systems, such as lights, blinds, heating, ventilation and air conditioning," says Matthias Stauber, technical project director for Sihlcity at Siemens BT.

Tenants as well as hotel guests can set their desired room climate. In Sihlcity, presence sensors in rooms, timer programs, and sensors that transmit exterior temperature to the management system determine actual demand. The system is then managed as energy efficiently as possible. For example, sensors measure CO₂ concentrations in conference rooms and theaters, and control air exchange according to how many people are present in a room. In the summer, unoccupied rooms are cooled by exterior air to drive down air conditioning demand.

Intelligent Home. Siemens researchers at Corporate Technology (CT) in Munich, Germany are looking further ahead. Their motto is "from smart homes to smart cities." On the seventh floor of Building 53 on the Siemens Campus, researchers are examining how processors, sensors, and network connections embedded in everyday items can take on control functions in building technology.

With a view to the more distant future, they are investigating how these can be applied to the optimum utilization of urban resources. In the lab, a complete apartment, fully equipped with Siemens household, electrical, building, communications and multimedia technology, is in operation as a living test environment. All of the devices can be controlled through a central communications node known as a gateway. Siemens has developed software that permits integration of various wireless protocols as well as interfaces to building technology systems. Corporate Technology has been demonstrating the results of its research in intelligent homes in Munich since 2006.

The test environment is systematically being expanded into a "pervasive computing lab"—an environment in which high-grade networked and distributed intelligent IT systems are embedded in everyday items that in turn recognize users’ needs, make decisions, and adjust themselves accordingly. New technologies developed by CT are to be installed and tested in the lab. "We are demonstrating first applications, showing how everyday items with embedded processors, sensors, and network connections can carry out their duties anywhere, at any time, in networked homes or in building technology," says Cornel Klein, a software and systems expert who coordinates CT’s pervasive computing activities.

Klein illustrates how autonomous such embedded systems have already become by pointing out that adaptive lighting systems can control natural as well as artificial light. "For example," he says, "we can squeeze wireless light and temperature sensors, a processor, a memory chip and a battery into a tiny box that can measure light. The goal is to have it communicate with sensors in blinds, and, after analysis of the measured values, control the blinds themselves."

Because such units consist of numerous IT systems that can be applied wirelessly to building technology, they can collectively amount to an intelligent energy management system—an important research goal. How the systems collect data, communicate with and issue commands to one another, are deciding factors in their own internal energy management. For example, to ensure that adaptive lighting can function for years without battery replacement, CT researchers have developed and integrated software that ensures that the sensors acquire data only when it is needed. At night, for instance, they go into "sleep mode" or collect far less data, because blinds do not need to be controlled.

More Efficient than Bluetooth. The choice of wireless protocol by which such sensors exchange data is important in achieving the lowest possible energy consumption. CT researchers selected the IEEE 802.15.4 standard, which consumes considerably less energy than Bluetooth, but operates on the same 2.4 GHz frequency.

This lays the groundwork for the application of wireless systems characterized by long service lives. For example, one goal is to eliminate the need for a control gateway, which would result in reduced installation costs in buildings. "Without resorting to a detour though a central gateway, the sensor networks themselves will analyze the measured data, compare the given target and actual values, and, for example, control blinds in accordance with measured values," Klein explains. Still, current blinds are not generally equipped with their own integrated sensor suite, and are therefore unable to detect their own condition, such as whether they are open or closed.

But sensor systems are proliferating. "Refrigerators, washing machines, dishwashers, and other appliances and systems are becoming increasingly intelligent," says Christoph Niedermeier, a software and energy expert at Siemens CT. Niedermeier explains that these devices use highly integrated information and communications technology, assisted by sensors and ingenious data processing, to measure their current energy consumption. In addition, they can communicate their condition to the outside world, for example, via Powerline networks. In this way, a refrigerator, deep freeze, washing machine and dishwasher can "agree" on when each device will be active.

A prerequisite for all of this is that such devices permit time-shifted operation. "The customer is then able to use less expensive electricity. Utilities, on the other hand, can avoid peak loads by responding to power surges  through the use of local generating units, such as with combined heat and power generation," says Niedermeier. He adds that future networks will incorporate decentralized energy consumers, and will thus making central control impossible.

"In the future, many decisions will be made on a local level, by embedded systems with access to a large amount of data regarding how and where optimization may be applied. These systems will be able to exercise intelligent self-management," he predicts.

Networked Cities. The extent of this research topic becomes more apparent when the smart home becomes part of a larger entity such as a smart neighborhood or even a smart city. In the future, many buildings could be networked with one another and managed by a multitude of distributed IT systems in an energy-efficient manner—which is the vision of the Pervasive Computing Lab. Several decades from now cities will have countless autonomous, intelligently functioning IT systems that will have perfect knowledge of users’ habits and energy consumption, and provide optimum service—for example, by bringing renewable energy online as needed.

In this vision, buildings not only communicate with buildings, or local energy generation units with power grids. Traffic signals know about traffic flow in a city as they exchange data and measured values with electric vehicles and simultaneously with electrical recharging stations, which in turn poll local, decentralized energy generators to see how much power they can supply. The goal of such a city is to optimally regulate and control resources by means of autonomous IT systems.
                                                                                                              Nikola Wohllaib