Saving Energy in the Big City

I recently spent two days at the American Society of Heating, Refrigerating and Air-Conditioning Engineers’ (ASHRAE) Existing Buildings in Urban Areas conference. The theme was very clear: a key to developing a sustainable future is to reduce the energy used by existing buildings. Gordon Holness, 2009–2010 ASHRAE president, said in his opening address that 75–85 percent of all buildings that exist today will still be here in 2030. Therefore, even if every new building were constructed as a net-zero-energy facility, it would not have much impact on the total energy use from all buildings.

Steps to a sustainable environment
There is plenty of available technology, but applying that technology is not going to improve things unless people change their habits—their cultures and mindsets. Holness said that most buildings deteriorate in energy performance during the first three years of use. Deterioration in actual use happens because most buildings don’t operate as intended, he said.

For a renovation job to affect energy consumption, the whole building has to be treated as a system. From the start, a major factor in energy use will be how the various building systems interact. For example, applying daylighting can decrease the electricity used for artificial lighting. But will increased sunlight mean increased load during air conditioning season, or will that load be balanced by the reduction in the heat generated by the electric lights? On the other hand, during heating season, will it reduce the need for burning fuel for heat? What about the increasing reliance on data storage? Should data storage facilities, with their high cooling requirements, be added to the building, or should data be sent to off-site centers? None of these questions have a simple answer, but all must be considered together in planning a successful energy-mindful building.

It isn’t just the system designers who have to be involved in planning; contractors have to learn to think on a systems level. They can’t just install their part and walk away. At least they shouldn’t. Systems have to be properly installed, commissioned and maintained. The article “Service With a Smile” (Electrical- Contractor, March 2010) made the point that including routine service as an important part of an electrical contracting business can help those contractors ride out the peaks and valleys of typical construction work. The convergence of building systems to improve energy savings can only be successful if these systems are constantly monitored and maintained; electrical contractors could be making that a part of their business.

The people factor
A theme that came up in most of the ASHRAE talks was that people are a vital factor determining whether energy savings will actually work. All of the sophisticated technology in the world won’t be of much use in a building unless the occupants are serious about sustainability. Holness pointed out that it is the building operator who determines whether the systems work according to design, and the primary role of the operator is to please tenants. The operator will tweak system settings to please their particular desires—say for heating and cooling—and there go the carefully worked out goals of the system designer.
Interactive systems have feedback loops, where outputs, such as lighting level or temperature, are sampled and fed back to the system controllers. In an integrated building, the occupants must become part of the feedback loop.

Steps for including people
There are two basic steps for bringing people into the loop. First, gather data about how much energy is used at what time and for what purpose. The second is to clearly communicate that information to the users so they can make better decisions about their energy use.

Paul Rode of Johnson Controls described a scenario in which LCD displays of usage data were set up in the lobby of an office building so that the workers would see it whenever they came in or out. This simple act, without anything being done to the building control systems, caused a significant reduction in energy. People made an effort to change their habits and bring down not just the overall amount, but the peaks in energy, for which buildings are charged.

For feedback from the people to be effective, metering has to been done at the tenant level, not just building-wide. This was the subject of a session titled “Engineering Solutions for Tenancy and Metering Issues.” The buzzwords here were submetering and smart metering. Submetering is metering usage by individual tenants. Smart metering gives more information than just the amount of electrical energy used. It records details such as a time record of usage, and it can store or transmit this information.

Holness concluded his address by enunciating perhaps the most important theme of this conference: “We need to develop a culture of sustainability.”
This topic will continue in next month’s column.

BROWN is an electrical engineer, technical writer and editor. For many years, he designed high-power electronics systems for industry, research laboratories and government. Reach him at or at, an independent professional writing service.

About the Author

Edward Brown

IBS Columnist and Freelance Writer
Edward Brown is an electrical engineer, freelance writer and editor who draws on his years of practical experience designing industrial processing and high-power electronics systems. In addition to writing the Integrated Building Systems column for E...

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