Power cuts are becoming increasingly common worldwide as electricity consumption soars and breakdowns in the electrical grid become more common. Extreme weather and widespread adoption of electric vehicles will add even more load in the coming years.
The buildings sector accounts for about 76% of electricity use and 40% of all U. S. primary energy use and associated greenhouse gas (GHG) emissions, making it essential to reduce energy consumption in buildings in order to meet national energy and environmental challenges and to reduce costs to building owners and tenants.
Providing a comfortable and healthy interior environment is one of the core functions of building energy systems and accounts for about a third of total building energy use. New technologies for heating, cooling, and ventilation not only can achieve large gains in efficiency, but they can improve the way building systems meet occupant needs and preferences by providing greater control, reducing unwanted temperature variations, and improving indoor air quality.
Energy use in buildings depends on a combination of good architecture and energy systems design and on effective operations and maintenance once the building is occupied. Buildings should be treated as sophisticated, integrated, interrelated systems. It should also be understood that different climates probably require different designs and equipment and that the performance and value of any component technology depend on the system in which it is embedded.
Buildings last for decades, so it’s important to consider technologies that can be used to retrofit existing buildings as well as new buildings. Retrofits present unique challenges, and technologies focused on retrofits merit attention because of the large, existing stock and its generally lower efficiency. These include low-cost solutions such as thin, easily-installed insulation, leak detectors, devices to detect equipment and systems problems (e.g., air conditioners low on refrigerants), and better ways to collect and disseminate best practices.
The major areas of energy consumption in buildings are heating, ventilation, and air conditioning—35% of total building energy; lighting—11%; major appliances (water heating, refrigerators and freezers, dryers)—18% with the remaining 36% in miscellaneous areas including electronics.
Lighting quality plays an essential role in the appeal and safety of interior and exterior spaces. Well-designed lighting systems can enhance productivity while glare and other harsh lighting features can decrease it. Light quality also affects sleep patterns and health and can shape the mood of any space. About 18% of U.S. electricity consumption and 6% of all U.S. energy consumption is used to provide indoor and outdoor lighting.
The key strategies for improving the efficiency and quality of lighting are good building and lighting design, window and window covering technologies (such as blinds and diffusers), lighting sensors and controls (including occupancy sensors and light sensors), and lighting devices (LEDs and others). Good lighting design can ensure that light levels are adjusted to user requirements.
While many lighting technologies are commercially available, the technology most likely to dominate the future is the LED. There are two major classes of LEDs: crystalline semiconductor devices LEDs that have many of the characteristics of silicon-based computer chips, and organic LEDs (OLEDs), which use organic materials that have the characteristics of semiconductors.
In commercial buildings, lighting plays a large role in energy use. Improved lighting efficiency decreases the heat energy released into the building by the lighting systems and thus reduces the demand for cooling. In the heating season, increasing lighting efficiency actually increases the demand for heating energy. This can be offset by improved insulation and heating equipment
Air conditioning involves both cooling the air and removing moisture. The traditional approach does both using vapor-compression heat pumps. Smaller systems, including most residential systems, move conditioned air while most large commercial buildings use central chillers to cool water and transfer heat from water to air closer to the occupied spaces. Dehumidification is the process of taking water out of air, and it accounts for nearly 3% of all U.S. energy use. It is typically achieved by inefficiently cooling moist air until the water vapor condenses out and then re-heating the air to a comfortable temperature, which is an inefficient process. Efficiency improvements in heating, ventilation, and air conditioning (HVAC) systems will involve efforts to improve the efficiency of heating or cooling air and technology that can efficiently remove moisture from air.
Refrigeration equipment, clothes dryers, washing machines, and many other building energy systems generate heat that is typically dumped into the ambient air. It is clearly possible, however, to capture and circulate this heat so that it can be reused (possibly after its temperature is increased). Waste heat from refrigeration could be used to help heat hot water.
About 36% of building energy use is distributed across a wide range of systems, the majority of them electric. These include a variety of electronic devices such as computers, televisions, imaging equipment (e.g., printers and multifunction devices), audio/video equipment other than displays, telephony devices, and network equipment. Kitchen and household devices are also included, as are application-specific commercial building systems. Electric vehicle chargers are also included in this category. They are now small, but their importance
may grow rapidly in coming years.
Water heaters, refrigerators, and clothes dryers are major energy consumers and are responsible for about 18% of all building energy use. Many of the technologies designed to improve whole building energy performance discussed earlier can also be used to increase the efficiency of these appliances. For example, water heating efficiency can be improved using advanced heat pumps, low-cost variable-speed motors, thin insulation, and other improved designs. Improved insulation and other strategies can reduce the losses from lengthy hot water
distribution systems in commercial buildings and large homes.
Computers and other electronic devices account for about 6% of all building energy use, and the U.S. Energy Information Administration forecasts that energy use in data center servers will increase five-fold by 2040, while energy use in other information technology equipment will more than double. The large energy requirements of computational facilities have led to increased interest in improving energy efficiency and finding ways to reduce their peak power consumption.
A smart building is a structure that utilizes automated processes to control the building’s operations like ventilation, air conditioning, lighting, heating, security, sanitation, and other core systems. These systems are linked together by Internet Protocol (IP) to collect data from the building. This allows the building to deliver services using the least amount of energy for lower costs and decreased environmental impact. Smart buildings help business owners, property managers, and occupants to be more efficient. The emergence of smart buildings has impacted infrastructures significantly by giving more to customers than just energy efficiency.
Lighting, windows, HVAC equipment, water heaters, and other building equipment are starting to be equipped with smart controllers and often wireless communications capabilities. These systems open many opportunities for improving building efficiency, managing peak loads, and providing services valuable to controlling the cost of large utility systems. They also offer many non-energy benefits that may be of greater interest to building owners and occupants than just energy usage. These include improved security, access control, fire and other
emergency detection and management, and identification of maintenance issues before they lead to serious problems. Low-cost sensors and controls also expand opportunities for individuals to have greater control of the thermal and lighting conditions, and if they power themselves using available light, vibrations, or fields generated by AC lines, it simplifies installation.
A Smart Building Energy Management System (SBEMS) is used to manage information technology employed in modern buildings. SBEMSs optimize total building performance by connecting independently operating subsystems integrating them into a smart power grid, making all the building’s operations visible in one place. A Smart Building Energy Management System allows for computer-based interactions between the building, its equipment, and the operators and occupants. It constantly collects all the available building data to empower decision-makers with new levels of visibility, control, and actionable information to react proactively to potential problems. An SBEMS also makes it possible for a building to be intelligent without much effort. The system only has to be integrated with sensors, actuators, and microchips which generate valuable data needed to automatically control conditions across an entire building. The system also has modules to handle floods and fire.
A smart building outfitted with smart systems improves health conditions significantly. Using wireless sensors to monitor CO2 levels and harmful small particles inside and outside the building systems are able to send out warnings that help businesses adjust ventilation, replace filters, and turn systems off as needed.
Continuous monitoring of air quality can boost employee cognitive functions and improve their overall health. Additionally, optimized cooling and ventilation equipment guarantees physical comfort, sanitation, and security. Optimal delivery of these elements helps to enable occupant performance and production.
The smart building energy solution significantly reduces everyday spending by identifying underutilized resources and maximizing the potential for growth in unused spaces. The building can also receive signals from the utility company to alter its electricity usage giving substantial savings on energy costs.
Smart buildings learn user needs, they remember user preferences and make predictions. The capacity to learn comes in handy when adjusting settings like room temperatures, lighting, shading, and energy and water utilization.
One solution is for buildings to create their own energy.
An Israeli company, TurboGen, has introduced efficient, relatively small and lightweight, easy-to-maintain microturbines that simultaneously generate electricity, heat and cooling. The microturbines can replace traditional boilers and air conditioners in multifamily residential buildings, public buildings, hotels, hospitals and offices. Based on proprietary jet-propulsion technology developed at Rafael Advanced Defense Systems, TurboGen microturbines make CCHP from natural gas. In the future, they could be powered by renewable solar, biogas and hydrogen fuels, says CEO Yaron Gilboa.
Natural gas goes into the microturbine to generate electricity. Extremely hot air produced as a byproduct of this process is collected for heating and cooling, Gilboa explains. “The hot air goes through a recuperator to a heat exchanger to heat water for bathrooms and kitchens. In the winter it also provides heat for the building,” says Gilboa. “In the summer, we use a dedicated chiller to convert the hot air for air conditioning and refrigeration.”
While a standard generator normally reaches 35 to 40 percent efficiency in terms of the energy it produces, Gilboa says, “the prototype we built at our lab in Petah Tikva will reach 90% efficiency by using the heat from the turbine as a source of energy. We use less natural gas to reach the same level of energy output.” TurboGen’s microturbines can produce independent electricity and heat for five years before requiring maintenance, says Gilboa.
“The advantages of the system are lowering electricity and heating costs in buildings, providing resistance to power outages, and reducing the amount of greenhouse gas emissions from buildings by replacing the boiler,” he says. “This technology can also lower real estate and rental prices of apartments and offices.”