Building Energy Resilience

Not too long ago, data center energy efficiency was an obscure and almost irrelevant topic of discussion for building managers and engineers. As our economy becomes increasingly digitized and productive, more and larger data centers have been developed to meet the digital demand. The media has recently reported that data centers now use close to 2 percent of global annual energy consumption. At this level of energy consumption, data center energy efficiency has rapidly become an important consideration for achieving energy conservation goals.

Are your lights on when you aren’t in your office? Do you have a problem with glare on screens or even direct line of sight glare? Bad lighting is a problem. Good lighting design is about more than energy efficiency, but should never be accomplished absent consideration of energy performance. In my last blog post I raised my concerns about the lack of progress in regulating lighting efficiency in Chapter 9 of ASHRAE 90.1. While the rest of the standard has made considerable strides in raising the bar driving more engineers and architects to learn and apply increasingly sophisticated solutions in their building designs, Chapter 9 effectively gives lighting designers a pass relative to efficiency. This translates to less efficient buildings overall as lighting efficiency “gains” in Chapter 9 are traded off against less efficient approaches to building envelope or HVAC design. In this post I want to talk solutions.

The International Space Station (ISS) recently had a breakdown in its external active thermal cooling system (the “EATCS”, because NASA loves acronyms!) that helps to keep systems inside and outside of the space station cool. For a little review of basics physics, let’s recall that space is a vacuum. In the same way that a vacuum flask keeps coffee piping hot for hours and hours, the Space Station is basically wrapped in a vacuum flask that keeps it from heating or cooling through ways in which we are typically familiar with. It can’t cool itself through conduction (i.e., heat passing through the outer wall) or convection (i.e., air moving heat away from the outer wall, thereby cooling it). These modes of heat transfer can’t work in space because there is no air surrounding the station to pass off waste heat to!

I have been involved with hundreds of projects in one capacity or another where I’ve designed or commissioned HVAC systems. With only a few exceptions, it’s been my experience that ductwork is never installed exactly as drawn. Most of the time it’s close. Usually, this is due to a lack of coordination during design requiring in-field modifications or a lack of detail when it comes to equipment hookups. We all expect design engineers to have their designs perfectly coordinated and their equipment details to be exact. I was on the design side for more than 10 years and I can tell you that there is never enough fee or enough time in the design schedule for that to be a reality. Until that changes, we’d all better expect field modifications.

Lighting controls in commercial building have undergone a transformation in the last few years. The simple wall switch (or no switch!) has given way to occupancy sensors and vacancy sensors with passive infrared (PIR) and ultrasonic motion detection. Additionally, photocell sensors have been added for daylighting control. The intent of these advances in lighting controls is to ensure that interior light fixtures are only on when occupants are in a space and natural light levels are inadequate. In my view, we still have a long way to go to achieve this intent across the building design and construction industries.

In facilities management and building owner circles, Preventative Maintenance (PM) contracts are seen (at least in theory) as a good way to outsource the routine maintenance of some/all building equipment. As an example, a HVAC PM contractor could change air filters in air handlers and terminal equipment, replace belts, drain and fill cooling tower systems before and after the winter, grease bearings, possibly perform chemical treatment of hydronic or condenser water systems, and perform other routine service tasks. The frequency and scope of service varies from contract to contract—some items are replaced on an as-needed basis—for example, belts may be inspected at some predefined interval, and replaced as wear is evident. Other tasks may be scheduled as a standard interval—such as filter changes. And still other tasks may be triggered by variables such as climactic conditions—for example, when a cooling tower is drained for the winter or refilled in the springtime.

With the hot, humid weather behind us, it’s time to review the status of our HVAC systems and ensure they are prepared to operate efficiently in the shoulder season and winter months.

Air source heat pumps have been around for a long time. Especially in climates more moderate than the northeastern United States, they have been the primary space conditioning equipment for a large fraction of homes. Relatively recent developments in high efficiency air-source heat pump technology have pushed heat pumps into colder climate zones such as the northeast US, and have pushed the technology into different end uses. Over the past several years, water-source heat pumps for domestic hot water heating applications have entered the marketplace in the US. Five years ago, heat pump water heaters (HPWH) were difficult to find; now, most major water heater brands have a heat pump water heater option.

You might have noticed that data analytics (i.e., “Big Data”) have been getting a lot of attention lately in the media. “Big Data” is now a common topic of discussion in media outlets covering business and technology ventures. “Big Data” generally refers to the work of corporations like Google and IBM that use large digital data sets of consumer or civil activities to reveal meaningful patterns and relationships that may be exploited. The recent growth of data analytics as a business venture is an outgrowth of increasing amounts and types of digital data, such as Internet search data, cell phone location data, and utility “smart meter” power consumption data. Smart meters now provide the unprecedented capability to collect and analyze real-time electric power consumption data across much of the electric grid. Right now there is considerable interest around using smart meters and data analytics to gain insight into energy efficiency opportunities in residential and commercial buildings.