Navigant Research Blog

Retrofits Are Key to an Energy Efficient Building Stock

— April 12, 2016

modern square and skyscrapersEven if all new buildings from today on were built to be net zero energy, it would take several decades for the change to have an appreciable effect on overall building energy consumption. Indeed, 50% of commercial buildings in the United States were built before 1980. Moreover, older buildings adhere to outdated standards—if they adhere to any standards at all—and often have higher energy intensities than new construction. Retrofitting these older buildings is the only path toward substantially reducing the energy footprint of the existing building stock.

Efficiency through Retrofits

In the world of retrofits, installing energy efficient heating, ventilation, and air conditioning (HVAC) systems; LED lighting; and building controls can help building managers lower the levels of energy consumption of building systems. For example, the 85-year-old Liberty Tower in Dayton, Ohio is using each of these strategies to improve energy efficiency. All interior and exterior lights in the 114,000-square-foot facility are being replaced with LEDs, the building’s existing steam boiler is being replaced with two vertical fire tube boilers, and the building controls are being replaced and upgraded to provide advanced programming measures.

Switching to LED lighting provides a substantial savings opportunity in existing buildings. In the case of Liberty Tower, the new lighting system is expected to use 60% less energy than the system it’s replacing. However, more savings are possible in LED retrofits through the addition of controls. Because LEDs provide better dimmability than fluorescent lights, they are better suited to controls. Even though the reduced energy consumption of LEDs reduces the amount of energy available to be saved, controls can allow an additional way of fine-tuning the amount of energy being used, thus providing more savings.

Lights can be dimmed when natural light is present or when a space is unoccupied to provide more savings. However, the level of light output during normal operation can also be adjusted based on feedback of occupants so that energy is not wasted providing more lighting than is needed. Additionally, LED lamps fail differently than incandescent or fluorescent lamps—they gradually grow dimmer at the end of their lifespan. As a result, using lighting controls to initially provide less than the entire output of the LED and steadily increasing output as the lamp fails could decrease the frequency at which lamps need to be replaced. This provides operational savings in addition to energy savings.

Upfront Costs

Though savings from retrofits can be substantial, so too can the costs. For the Liberty Tower retrofit project, the total cost is estimated to be $870,000 and provide annual utility cost savings of $99,000, generating a payback period of 8 years. The payback period, for better or for worse, is considered by many in the industry as an easy shorthand for determining whether or not a given energy efficiency retrofit project or technology will be viable for a particular installation. Most building owners require a payback of 3 years or less, though this depends on the ownership and use of the building.

Liberty Savings Bank owns the Liberty Tower and occupies about 10% of the total floorspace, with the remainder leased to tenants. Because the company is family-owned and occupies part of the building, it can accept a larger payback. However, only about 60% of commercial floorspace in the United States is occupied by its owner. Consequently, larger ticket upgrades, such as deep building envelope or HVAC system upgrades, remain difficult to sell within the retrofit market.

Moreover, because retrofits are prioritized by their payback period and generally have a long lifespan, opportunities with unattractive longer payback periods are the ones that remain. Without either a change in technology or an outside force, the energy savings potential of these opportunities may go unrealized. In the case of Liberty Tower, the project is expected to generate more than $70,000 in utility rebates, making the economic case more practical. With commercial buildings accounting for more than a third of total U.S. energy consumption, regulations and incentives will be the key to reducing the energy footprint of the existing building stock.

Join Benjamin Freas at the Navigant Research’s Retrofits for Commercial Buildings: Moving the Needle on Energy Efficiency in Existing Buildings webinar on Tuesday, April 19, 2016 at 2:00 pm EDT to learn more about energy efficiency in buildings.


Drones or Data for Facilities Management?

— March 7, 2016

Luftbild einer Windkraftanlage mit Drohne Rotorblatt Wartung InspektionThe potential benefits of unmanned aerial vehicles, commonly known as drones, have received a lot of attention as more and more applications have been identified. In addition to their continued use in warfare, drones are emerging as a useful tool for everything from wind turbine inspection to stopping poachers and spotting sharks. The seemingly infinite possibilities for drones have now extended to commercial buildings, where they can be used to provide visual inspections of hard-to-access spaces.

The use of drones by facilities managers seems like a smart move. Technicians no longer need dangerous ladders or expensive scaffolding to inspect the conditions of their facilities. However, drones are not the transformative change that facilities management needs. Physical inspection is the old way of thinking—it has been a necessity driven by technological limitations. Though drones now present the opportunity to enhance the process, the process itself is fundamentally flawed. While not as flashy, advances in building energy management systems (BEMSs) create the promise of technology’s ability to change the maintenance paradigm.

Data, Not Drones

The problem is not in drones, but rather, in a management strategy that relies on periodic visual inspection. Facilities managers will only find problems if they are looking for them, but that’s not a guarantee that these problems will be found before they affect operations. The inspector needs to know what to look for, the problem has to have symptoms that can be seen visually, and the inspections need to occur regularly.

Even if the manual process of drone inspection does properly identify problems, maintenance to address those problems still needs to be scheduled. The more sophisticated solution is to rely on building data. By understanding how a building operates and monitoring for deviations from that baseline, problems can be automatically identified. Moreover, fault detection from building data can be directly integrated into workforce management software so that the labor needed to address problems is actually performed.

Vendor Challenges

The challenge for vendors of building systems is that building owners and operators don’t have much of an appetite for reducing operating costs through capital investment. After all, paying for the installation and integration of sensors now may provide cost savings in the future. On the other hand, those savings might never be realized. Or that conversation could never happen because investment is focused on business operations to grow revenue rather than to cut the cost of operating the building.

As a result, the idea of inspections with a drone are promising because they do not require capital investment, yet produce some operational savings. They are also flashy new pieces of technology with lots of buzz. However, investment in BEMSs provides a meaningful alternative strategy to the management of operations and maintenance. What’s more, unlike drones, BEMSs have the ability to shift operations and maintenance procedures from a reactive process to proactive approach.


Washington, D.C., the Future of Buildings

— February 4, 2016

modern square and skyscrapersWashington, D.C. is fast becoming the hub of smart building innovation. According to the U.S. Green Building Council’s Annual Top 10 States for LEED Green Building report, the region has been described as the epicenter of green building. Indeed, if Washington, D.C. were a state (which it should be), it would have the highest per capita LEED-certified gross square footage of any state—19.3 (compared to 3.4 in Illinois, for example). Of course, some say Washington, D.C. should never be compared to a state. Yet the city only trails 5 states in total LEED-certified floor space.

One path to greener buildings is through more intelligent buildings. When the systems that run buildings are better able to sense and react to real-world conditions, they are able to use less energy and create a healthier, more comfortable environment. This has translated into the steady expansion of sensors and controls that connect to each other and to the Internet—see Navigant Research’s Internet of Things (IoT) for Residential Customers report for a more in-depth view. Though better connected buildings solve some problems, increased Internet connectivity can create substantial cyber security threats.

To Security and Beyond

Historically, buildings systems—such as lighting, HVAC, and security and access controls—have existed on their own isolated networks. Integrating them together not only provides opportunities for efficiencies in management, it also creates a rich source of data for analytics and optimization. To accomplish that, these once-isolated networks need to connect to the Internet.

On the face of it, there doesn’t seem to be a threat for anything more than a nuisance. What is the problem if someone alters the temperature in a building? The problem is that once a device on a building network is compromised, it can be used as a point of attack for other devices on the network. As a result, the increased convergence of building systems and IT systems can leave companies’ entire IT systems vulnerable to attacks routed through building systems.

Though these cyber vulnerabilities threaten intelligent buildings themselves, they may not threaten Washington’s reign over smart building installations. Washington, D.C. could see $1 billion in cyber venture funding in 2016. As industries that rely on things connected to the Internet—such as robotics, the IoT, and intelligent buildings—continue to flourish, the need for advanced security will drive investment.


Air Conditioning Controls Overlook Comfort

— August 12, 2015

If you work in an office or know someone who does, you have probably already heard that the patriarchy has set the thermostat too low. A recent study by two Dutch researchers seemingly provided proof of this institutional sexism and promptly set off an Internet firestorm. The study claims that the model that ties thermal comfort to the air temperature used for the control of air conditioning systems relies only on data from men. Moreover, because the metabolic rate of males and females are different, the approach provides too much cooling for female occupants, leaving them to suffer in frigid conditions while their male counterparts are comfortable. The study is unfortunately wrong on two counts: air temperature settings are based on data from equal amounts of men and women, and both men and women suffer from temperatures that are too cold.

If You Can’t Measure It, You Can’t Manage It

Controls for air conditioning need to be set to something that can be measured. Thus, air temperature, which can be measured and is highly correlated to thermal comfort, is used to manage the operation of air conditioning equipment. The specific temperatures engineers use for systems are set by the American Society of Heating, Refrigerating, and Air-Conditioning Engineer’s (ASHRAE’s) Standard 55, Thermal Environmental Conditions for Human Occupancy. In a press release, ASHRAE reiterated the fact that Standard 55 is based on the preferred temperature of more than 1,000 subjects with an equal amount of men and women. Unlike paychecks, Standard 55 does not have a gender bias.

The problem highlighted by response to the Dutch study is that temperature and comfort are related but not identical. How comfortable a person feels in a building depends on how much cooling they need (what they are doing, what they are wearing, how old they are, and their body fat) and the state of the air that is provided (temperature, humidity, volume, and speed). Controlling a system that depends on a dozen variables by a single variable leads to both women and men being uncomfortable. Saying that the average person is comfortable at a certain temperature is akin to describing a person with a chicken and a person without a chicken as two people who have an average of half a chicken.

Utopia with the Dialogue of Comfort

Wouldn’t it be great if air conditioning was controlled by comfort rather than temperature? Historically, this dream has been technologically unfeasible. To truly measure comfort, the feelings of building occupants need to be gathered. Not only are engineers bad with feelings, but there isn’t a sensor that can measure them. Nonetheless, air conditioning systems are moving toward comfort-based control.

The Leadership in Energy & Environmental Design (LEED) building certification program, which rates buildings based on their indoor environment and ecological impact, credits building operators for assessing how comfortably occupants actually are through a survey. Building Robotics, an Oakland-based startup, closes the comfort control loop with its Comfy software. Rather than relying on exclusively on sensors, Comfy has occupants provide direct feedback via a web or smartphone app and changes temperature and airflow accordingly. As better technology enables better building controls, women and men alike will be able to find comfort in the built environment.


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