Personalized Office Comfort System Could Save 30% In Building Energy Costs

At the Center for the Built Environment (CBE), researchers at the University of California, Berkeley (often called UC Berkeley) have developed a Personal Comfort System (PCS) designed to cool and heat the parts of the body which are most “thermally sensitive.” This was done with the assistance of a $1.6 million grant from the California Energy Commission.

The areas the system targets include the feet, torso, and face/head. The cooling and heating devices are in the form of foot warmers and a network of web-based applications, devices integrated into chairs, and tiny fans which can quickly cool and warm users on demand, and the system is powered by a rechargeable lithium ferrophosphate battery, according to the source, UC Berkeley.

On average, the PCS uses 2 watts for cooling, and 40 watts for heating. The foot warmers utilize halogen lamps which operate at 20 watts on average throughout a typical winter day, which is far less than their maximum of 160 watts (I have a 120 watt lamp which is very similar to halogen lamps, and it is a very effective foot warmer). In comparison, space heaters operate at up to 1,500 watts, as they are designed to heat entire rooms, rather than the occupants only, as the PCS does.

It is predicted that this system has the potential to reduce natural gas usage by 39%, and electricity usage for heating, ventilation, and air conditioning (HVAC) by 30%. It was also found that the system may be able to save California $69 million annually in energy costs, while eliminating 247,000 tons of CO2 emissions.

Another important feature which the PCS has, which air conditioners and heaters lack, is the ability to shut themselves off when there are no users present. Air conditioner manufacturers are not to blame for this, as it is difficult to implement such a feature reliably. However, it is much easier to integrate this feature into a foot warmer, as various types of sensors can be used to detect the presence of feet. Chairs can also detect occupants.

The PCS is a distributed heating and cooling system which provides a convenience benefit, as it enables more control over temperatures at each workstation, to reduce the incidence of coworker conflicts about who gets to adjust the room air conditioners to their preferred temperature. In other words, workers can just cool themselves off as they see fit (to some extent) without making coworkers too cold. It will also interface with smart phone apps, software, and sensors to relay building temperatures, weather forecasts, and user satisfaction data.

As Edward Arens, the project’s co-principal investigator and a professor of architecture and director of CBE, said “It’s even better than having a thermostat at every workstation, if that were possible.”

Others which assisted the CBE with the project include UC Berkeley’s David Culler, co-principal investigator and professor of Electrical Engineering and Computer Science; the campus-based California Institute for Energy and Environment; and Taylor Engineering, a private firm specializing in design of energy-efficient building systems. The research will be supported by the campus’s Operational Excellence Energy Management Program.

There is also a consortium of 40 industry members that support this project, including, but not limited to: Pacific Gas & Electric Co. (PG&E), and the architectural and engineering firms HOK, LPA, and Perkins + Will. These firms plan to engage in field installation and other research initiatives.

100 prototypes of specially equipped mesh chairs with built-in heating and cooling are being developed for the future.