Maggie Koerth-Baker, editor of Consulting-Specifying Engineer
Previously, office buildings that feature environmentally friendly engineering systems were built only in states like California and Oregon.
Back then, the word “ecology” was more associated with idealists who simply did not understand the cost of construction. But now the situation is changing.
“Sustainability is becoming more and more a part of building standards,” says Scott Frank, a partner in the New York office of Jaros, Baum & Bolles. “These days, almost all property owners require at least LEED certification. Those who don’t care are in the minority.” Frank is referring, of course, to the U.S. Green Building Council’s LEED certification, which measures a building’s “green credentials.”
Moreover, according to the engineers themselves, property owners often insist on the use of individual technologies, which brings environmentally friendly utility systems to the forefront.
“The traditional approach is to find a design that takes one of the most popular technologies and apply it to a traditional building,” says Steven Turner, managing director of CTG Energetics. “Now you’ll walk into an office and find the required raised floor, the required level of radiant heating, and high-efficiency glazing. It’s amazing to have so many new technologies in front of you.” CTG Energetics is a nationally known company with offices in every state.
Ironically, as green building advances, engineers are reviving some of the jettisoned ideas of the past and discovering new ways to approach the design process itself. The result is amazing office building solutions that are both easy to build and sustainable.
Integrated approach
If building owners want a construction project to be energy-efficient and cost-effective in the long term, then any engineer knows that it is necessary for the technologies and systems used to complement each other.
All it takes is true teamwork and a little computer support. When New York-based Syska Hennessy began designing the Region 8 headquarters building in Denver, it began with a comprehensive review of both the existing architectural solutions and the various engineering systems. David Callan, Syska Hennessy’s principal in charge of finding compromises between structural strength and constructability, says that partnering early in the construction process helps the firm select the best systems and solutions, despite the fact that the architectural project is already unique in many ways. In his view, the solutions selected are the best fit for the climate and location.
Computer modeling also played a significant role in calculating energy consumption, which helped make the Region 8 project truly green. Thanks to specialized software, building owners can now clearly see how “savings” on even one of the technologies used could affect the entire project as a whole.
Early integration is widely acknowledged to be beneficial for building technology. “We used to get a plan from the architects and hand it off to the civil engineers to plan the installation work,” says Turner. “Now we have a more ‘interactive’ process where collaboration starts from day one.”
The upshot is clear. Research has shown that an integrated approach and continuous collaboration are the best way to create a green building and save money. Collan cites a recent report on LEED certification from the U.S. General Services Administration (GSA).
“It’s generally accepted that teamwork in building and using LEED standards can save you money,” Collan notes. “But if you build the old-fashioned way and only implement new green technologies at the end, when everything is already done, it will cost you even more.”
People are everything!
When it comes to green building trends, there is another important factor besides finances.
“To keep the cost of living in residential buildings to a minimum, you need to reduce energy consumption per square meter,” says Scott Jordan, marketing manager at Schneider Electric. “If the customer is not satisfied, the work cannot be called successful.”
The direct relationship between workplace comfort and employee productivity has been demonstrated more than once or twice. The most recent evidence of this connection was a 2006 survey conducted by the American company Gensler. The survey showed that almost half of the office workers surveyed were able to work an additional effective hour a day if they were provided with better working conditions.
One way to improve office comfort is to design the building to allow daylight into the space. But while most workers love natural light, large window areas are not ideal. Many will find it uncomfortable, and it is not energy efficient. “If you don’t plan ahead, daylight can create spots where it is impossible to work,” says Mike Hatten, principal at SOLARC in Eugene, Oregon.
To balance all aspects of the design, the engineers decided to turn to real, full-size models.
For example, when the daylighting system was being developed for the New York Times office building, specialists from the Berkeley National Laboratory built a 418 sq. m. model, where they tested the placement of equipment and workstations. The result was a modern lighting system that reduced lighting costs by 10–60%, depending on the location of the workstation.
A similar system is equipped with blinds that automatically lower and raise during the day depending on the nature of the lighting, so that bright sun spots do not form in the office.
In other buildings, engineers are reducing solar gain by optimizing glazing and using electrochromatic glass from Minnesota-based Sage Electrochromics and Faribault.
SageGlass can instantly change tint, allowing only 3.5 percent of visible light to pass through.
It does this with the push of a button, allowing office workers to choose which panes of glass to shade to reduce glare while other panes remain clear.
Unfortunately, people themselves can ruin an optimal lighting design by using office space in ways that designers don't anticipate.
Rebuilding a fixed wiring system can be very expensive. However, a solution to this problem is on the horizon. The Convia system, created by Michigan-based Herman Miller and Zeeland, with consultants from Minnesota-based The Weidt Group, was recently announced for release.
The Convia system optimizes lighting according to changing external conditions. “We can implement this system by taking a broader view of the design process,” says David Ejadi, who works for the Weidt Group. “With this system, you can take control of all aspects of lighting: from daylight sensors to the interior lighting sources themselves. Depending on the arrangement of people in the office, you can adapt the lighting to their needs yourself, without having to call in an electrician.”
By pointing a wireless device at the daylight sensor, you can reconfigure the lighting system yourself.
An alternative to air conditioners
The air quality in an office largely determines both the overall ecology of the project and the comfort of the employees. Syska Hennessy's architectural solution for the Environmental Protection Agency building (called Region 8) includes a dual ventilation and air conditioning system. This system uses a separate, load-independent supply of outside air to ensure the required air exchange and the required humidity level. Separate control of the two parameters allows the operator to maintain more comfortable conditions for employees, eliminating excess humidity.
This system provides a constant supply of fresh and clean air to the offices of the Region 8 building.
The dual ventilation system is just one example of a growing number of options being used by engineers looking to move away from the traditional mechanical air handling systems that have been popular since the 1950s, says Collan. “It’s a fairly common solution for natural ventilation and air conditioning,” he says. “It gives you predictable results, but you don’t get the energy savings or the cost savings.” Alternative climate technologies include old ideas like condensing boilers and geothermal energy, as well as newer systems like raised-floor ductwork and natural ventilation systems, which are becoming increasingly popular.
Among these technologies, underfloor ductwork stands out. The preferred system for such showcase facilities as One Bryant Park and EPA Region 8, as well as smaller buildings such as the Natural Resources Defense Council headquarters in Santa Monica, California (CTG Energetics) and Banner Bank in Boise, Idaho (SOLARC), is underfloor ductwork. It is this system that provides cost savings during installation and energy savings during operation. Air is supplied at floor level to the work area where it is needed most, and then rises to the exhaust system where it is exhausted.
The system does not waste additional energy, ensuring ideal mixing of the internal air. In this case, natural air convection is even preferable.
Such a system requires less energy for cooling, since it would be too uncomfortable to supply air with a temperature of 10 ° C to the work area. The ventilation system running under the floor achieves the same cooling effect already at an air temperature of 16 ° C. In addition to temperature comfort, air ducts running under the floor are not so expensive and can save tenants money, and also make it possible to rearrange furniture in the office. In addition, such a system offers a person a greater level of comfort and the ability to individually adjust the parameters. An office worker can use a valve to adjust the parameters of his own workspace, making it more comfortable, while the temperature in the room as a whole and the air flow remain under the control of the central operator.
According to many experts, this ventilation system, as well as raised floors in general, could become the norm in office design in the next decade.
Alternative to the power grid
Alternative power is another significant trend in green building, and building owners themselves understand this.
“The trend now is to offer building owners alternative energy options other than traditional power,” Turner says.
One of the significant alternative energy sources is the combined production of thermal and electrical energy.
An example of this is the 5 MW power plant built by Jaros, Baum & Bolles in Bryant Park, New York. It uses a new type of turbine made by Solar Turbines Inc. The plant, called Mercury, can run on a variety of fuels, including natural gas, coal, and biomass, producing extremely low emissions (about 9 ppm for NOx, 20 ppm for CO, and unburned hydrocarbons). The fact that the plant can produce heat allows it to be utilized efficiently. In the winter, the plant produces its own heat.
Another way to generate electricity has become popular much more recently. We are talking about photovoltaic systems. The latest innovation in this area is flexible photovoltaic cells connected to a network. There are other innovations that Reilly, President and Chairman of the Board of Directors of the Athena Institute in Seattle, tells us about. This institute is engaged in the production of next-generation solar cells (capable of accumulating heat and generating electricity). Solar cells are now part of an integrated energy system, which was not the case before. This technology has grown around “smart” glass developed at the National Renewable Energy Laboratory.
The glass that not only shades but also functions as a solar power plant has been called “smart”. “This allows you to convert bright sunlight that interferes with your work into electricity,” says Reilly. “It will be great if this technology finds application.”
But some engineers believe that property owners will turn down what they see as an expensive “green” technology, opting to source their energy from outside. They will sign long-term contracts with wind power “stations,” which gives them three advantages. “You get a source of clean energy that costs less than what you get from a thermal power plant,” Turner says. “The money you pay them, the wind power plants, invest in new installations.”
According to Collan, many building owners will also refuse solar energy because they do not want to complicate their home with excesses. According to the expert, home systems often do not provide enough energy to make it worthwhile to install them. You can get real economic and environmental benefits from wind power. “This is how your dollars will work best,” the expert concludes. “It is not so original, but it makes sense.”
Hit the “bullseye”
Ecological heating, ventilation and air conditioning systems, as well as building automation systems, focus on the necessary flexibility and versatility of solutions to provide office workers with comfort, a positive attitude and high productivity.
Solving this complex problem, according to Stephen Turner of CTG Energetics, is like hitting the bull's eye. It's a matter of finding the element of the system that provides the greatest level of flexibility and control without overcomplicating or confusing the system as a whole. If you can do that, you'll be able to regulate the air flow in an individual workspace, and in some cases, its temperature. At the same time, the system operator will receive more information, allowing them to set the microclimate to the owners' liking. Such a system will also allow operators to control lighting, poll security alarms, and, more importantly for new buildings, implement a billing policy based on meter readings.
Lighting Problems
Over the past three years, engineers have seen previously toothless codes gain funding and legal backing. Scott Jordan, a marketing manager at Schneider Electric, has risen to prominence.
“Lighting control used to be a stand-alone system, an afterthought for engineers,” says Scott. “But it’s critical, especially in elevators and other spaces where lighting is a must.” To find the sweet spot between projected energy costs and control system requirements, building owners and engineers are increasingly turning to automated control systems. Key to the system are controllable ballasts, which can be controlled in four different ways: switches; occupancy sensors; automated daylighting systems; and photosensors, which can be adjusted in groups or individually by a central computer.
Another key feature of the Square D system from Schneider Electric is the ability to control lighting directly over the Internet. The network-based systems allow operators to access a single lamp via the ballast, as well as control a whole group of lamps and receive warning messages via e-mail.
These systems have proven popular over time.
Such systems are appearing in such large projects as the power plant building in New York's Bryant Park, built by Jaros, Baum & Bolles (the building area is 195 thousand square meters), as well as in the smaller-scale Banner Bank building in Boise, Idaho (designed by Oregon-based SOLARC Architecture and Engineering).
Synthesis of construction technologies
As green building approaches move from a blueprint to a solution, the design approach itself is changing. “We start with a model that visualizes the building and allows us to look at it as an integrated system. We see how the natural and artificial lighting systems interact, as well as the air conditioning system,” says Mike Hatten, Principal, SOLARC Architecture and Engineering, Oregon. As an example, Mike cites the impact of window placement on the operation of air conditioning systems.
Typically, such systems are located on the south side of the building, which in some cases reduces the load on the cooling system by as much as 10%. Hatten regrets that when developing energy-saving measures, windows are the first to suffer. However, when specialized engineers take on the design of an air conditioning system, windows become the first issue. The traditional belief in the need for shading is more harmful than beneficial. Moreover, errors in this matter increase energy consumption during the operation of the building. “You won’t be able to fix it later without a major redesign of the air conditioning system,” warns Hatten.
Based on materials from the magazine
Consulting-Specifying Engineer.