Personal Comfort Systems Could Slash Office Energy Use by 30 Percent

Forget the sweater, what if office temperatures were tailored to each worker?

2 min read
Personal Comfort Systems Could Slash Office Energy Use by 30 Percent

No one ever seems happy with the temperature in the office. Someone has a sweater stashed away in a drawer to throw on when the air conditioning blasts in summer, while another worker, seated one desk over, is always sweating in winter.

Researchers at the University of California at Berkeley’s Center for the Built Environment (CBE) recently received a US $1.6 million grant to tackle this long-standing problem. Their solution: a Personal Comfort System (PCS) that not only keeps individuals happy at their desks, but also provides feedback to the building’s facility managers so they can fine-tune the heating, ventilation, and cooling (HVAC) system.

“It’s even better than having a thermostat at every workstation, if that were possible,” Edward Arens, the center's director and the project’s co-principal investigator, said in a statement.

The PCS has foot warmers, fans and low-wattage devices embedded into office chairs to warm or cool an office worker on demand. The system focuses on the most thermally sensitive parts of the body, such as the head and feet, which is more efficient than maintaining one temperature for an entire office space.

On average, the PCS uses 2 watts for cooling and 40 watts for heating, far lower than the 1500 watts that a conventional space heater uses. The entire system operates on a rechargeable lithium ferrophosphate battery and turns off when the user leaves his or her desk.

The PCS's sensors don't just yield benefits in terms of comfort. The information they relay to facilities managers give greater control over the building’s energy consumption. The goal of the project is to integrate occupant information with cutting-edge energy controls and computer sciences to cut energy use. The researchers have found that for a typical California commercial office space, the systems can cut HVAC electricity use by up to 30 percent and cut natural gas use by 39 percent. The team will put together about a hundred prototypes of the special heating-cooling chairs for pilot studies.

The researchers are working with architectural and engineering firms and also the local utility, Pacific Gas & Electric. Even with a multitude of stakeholders, there are plenty of challenges. There are issues with integrating new technologies into legacy HVAC systems, and competition from other technologies that can also save energy.

Advanced occupancy sensors, for instance, can fine-tune HVAC output and lighting level based on how many people are in a room. Social networks can help building managers engage tenants in energy efficiency programs. Other upgrades, such as sensors on key pieces of equipment, can also save energy without involving fickle tenants at all. New technologies for HVAC and chiller systems can slash electricity use when they replace older, less-efficient systems.

For the average office worker, however, the idea of personal comfort system is a welcome concept. It might even free up the sweater drawer for another use.


Photos: Center for the Built Environment

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Smokey the AI

Smart image analysis algorithms, fed by cameras carried by drones and ground vehicles, can help power companies prevent forest fires

7 min read
Smokey the AI

The 2021 Dixie Fire in northern California is suspected of being caused by Pacific Gas & Electric's equipment. The fire is the second-largest in California history.

Robyn Beck/AFP/Getty Images

The 2020 fire season in the United States was the worst in at least 70 years, with some 4 million hectares burned on the west coast alone. These West Coast fires killed at least 37 people, destroyed hundreds of structures, caused nearly US $20 billion in damage, and filled the air with smoke that threatened the health of millions of people. And this was on top of a 2018 fire season that burned more than 700,000 hectares of land in California, and a 2019-to-2020 wildfire season in Australia that torched nearly 18 million hectares.

While some of these fires started from human carelessness—or arson—far too many were sparked and spread by the electrical power infrastructure and power lines. The California Department of Forestry and Fire Protection (Cal Fire) calculates that nearly 100,000 burned hectares of those 2018 California fires were the fault of the electric power infrastructure, including the devastating Camp Fire, which wiped out most of the town of Paradise. And in July of this year, Pacific Gas & Electric indicated that blown fuses on one of its utility poles may have sparked the Dixie Fire, which burned nearly 400,000 hectares.

Until these recent disasters, most people, even those living in vulnerable areas, didn't give much thought to the fire risk from the electrical infrastructure. Power companies trim trees and inspect lines on a regular—if not particularly frequent—basis.

However, the frequency of these inspections has changed little over the years, even though climate change is causing drier and hotter weather conditions that lead up to more intense wildfires. In addition, many key electrical components are beyond their shelf lives, including insulators, transformers, arrestors, and splices that are more than 40 years old. Many transmission towers, most built for a 40-year lifespan, are entering their final decade.

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