Just like technologies in most other industries, heating and cooling technologies continue to advance at rapid speeds. The days of wall radiators and window air conditioning units are long gone for many consumers, replaced by central heat and air. But some point out that these methods, too, are inefficient and costly.
Modern methods of heating and cooling homes and businesses hinge on maintaining a constant temperature throughout the structure, even in rooms that aren’t currently being used and areas, like lobbies, that aren’t as well-used. The problem is exacerbated in offices and large public buildings, where heating and cooling costs can grow exponentially when compared to the costs of heating or cooling a private residence.
Researchers at the MIT SENSEable City Lab have developed a new heating and cooling system, which they call Cloud Cast and Local Warming. The system uses a ceiling-mounted network to sense where people are in a space and keep them comfortable by directing a temperature-controlled cloud of cool or warm air directly at each person.
The Wi-Fi-enabled system follows occupants as they move around a room or building, so that the air around each person is heated or cooled while most of the air in the room remains without climate control. The system is still in prototype stages, but it could soon begin to appear in public spaces and could one day even replace your old central heating and air system. For now though, you can still get the latest models installed to keep your home heated and cooled efficiently.
How Cloud Cast and Local Warming Works
The Cloud Cast/Local Warming system uses Wi-Fi based motion sensing and tracking to detect human occupants in a space, figuring out how big they are, and following them as they move around. The system then directs an individual blast of cool or warm air at each person in the room, depending on whether it’s set on cooling or heating.
Professor Carlo Ratti, who acts as the director of the MIT SENSEable City Lab, described the mechanism thusly: “In the Cloud Cast installation, ultrasonic sensors embedded in the suspended canopy structure detect passers by interpreting the echoes from high frequency sound waves.” By measuring the amount of time that passes between sending the signal and receiving it again, the device can accurately determine how far away a person is and how much of the room he or she is occupying.
MIT researchers presented the prototype for the first time last year at the 14th Venice Architecture Biennale, on July 4, 2014. MIT developed the technology that senses when a person enters the room and tracks the person’s movements throughout the room, responding with blasts of cool or hot air to create a personalized thermal bubble around each room occupant. The heating and cooling elements themselves can be placed in a grid on the ceiling. Servo motors allow the heating and cooling elements to direct cool or hot air in different directions. The heating element uses infrared radiation, a mirror, and focusing optics to create columns of warm air that follow room occupants around. Ratti believes the system would be very easy to integrate into the false ceilings many businesses and public buildings already use. Eventually, smart phone apps could be developed that would allow individuals to personalize the temperature of their individual clouds of hot or cold air.
Will You Use Cloud Cast and Local Warming in Your Home Someday?
Though the device is still in its prototype stages, Ratti and his colleagues believe that the first uses of this new system will be commercial. It would be ideal for office buildings that are expensive to heat and cool, and would also be well-suited to large spaces like lobbies or outdoor spaces, like patios, where conventional heating and cooling methods have been inefficient. Ratti believes that Cloud Cast and Local Warming could cut heating and cooling costs for businesses and large public buildings by as much as 90 percent.
Ratti told Wired that heating buildings is one of the biggest drains on energy resources in the world today. “Buildings are heated 24 hours a day, even when nobody is in them, and empty corners of the building are indiscriminately kept just as warm as rooms that are in active use. The technologies underlying Local Warming could address this asymmetry by synchronizing climate control with human presence, vastly improving the energy efficiency of buildings,” he said.
While Local Warming might be appropriate for homes and businesses in many climates, Cloud Cast is best suited for homes and businesses in hot, arid regions, rather than hot, humid ones. That’s because it relies on evaporative cooling to make room occupants feel comfortable, and evaporative cooling is less effective in humid environments. That’s why “dry heat” is more comfortable than humid heat; in arid climates, sweat evaporates more quickly, for efficient evaporative cooling.
For the moment, cutting down on heating and cooling energy consumption mostly involves turning down the thermostat and sealing the windows. But in the very near future, efficient heating and cooling could mean heating or cooling just the air that surrounds your body, saving the cost of heating or cooling an entire house or room, for a fraction of the cost.