By Mark Handzel
Green building accounts for nearly half of all new nonresidential construction, according to 2015 numbers by the U.S. Green Building Council (USGBC), driven in part by strong market demand and more stringent environmental policies at the federal, state, and municipal levels.
Cities such as Chicago, Boston, Washington, DC, and New York are developing policies that require commercial buildings to benchmark and disclose energy ratings, as well as perform audits and retro-commissioning. The federal government has set a goal that by 2030 all new federal buildings must achieve net-zero energy consumption, meaning the total amount of energy a building consumes is roughly equal to the amount of renewable energy created on the site. And nearly a dozen states have passed legislation to reduce energy consumption in buildings.
According to the USGBC, current market trends suggest that building owners and managers will invest an estimated $960 billion between now and 2023 on greening their existing built infrastructure. The desire to conform to emerging green building codes and standards — coupled with a focus on cutting costs, reducing energy consumption, and shrinking carbon footprints—is driving the urgent pursuit of greater energy and water efficiency in commercial buildings.
With such buildings consuming nearly one-fifth of the energy in the U.S. — and an estimated 30% of that energy wasted — this segment offers a tremendous opportunity for efficiency improvements.
Given that a standard HVAC system represents 40% of a commercial building’s total energy use, this is a logical place to start. Engineers who adopt a highly integrated approach to system design will achieve efficiencies in operations and realize long-term cost-savings.
When ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) renovated its headquarters in Atlanta in 2008, its goal was to be an industry model of efficiency and sustainability. By using a systems approach in its selection of a new ground source heat pump system, it achieved this goal. The building received LEED Platinum status and exceeded the ASHRAE 90.1 standard by more than 30%.
HVAC Design: Systems Solutions
Smart designers and managers understand that energy efficient components don’t work in silos. These need to work together as a complete system to achieve the highest efficiencies. New HVAC systems and retrofit projects can be massive undertakings, but with a strategic hydronics system solution planned from the start, project leaders can help maximize energy savings.
Water is key in many HVAC systems because it is the most efficient conductor of heat or cold. Technological advances are enabling designers to develop rapid prototypes of products such as pumps that offer better and longer lasting efficiencies. A newly released ruling by the U.S. Department of Energy will require clean-water pumps to meet efficiency standards by 2020, which has spurred an even greater focus on efficiency by pump manufacturers.
Yet an HVAC system made up of the highest efficiency components will only enjoy the efficiency gains of the individual components if it is designed, installed, and operated as a system.
During a -4° day in Chicago in January, a heating system will be operating at peak load to raise the building temperature to a comfortable level. When the outdoor temperature rises 40°, the system will not have to run at full speed to ensure indoor comfort. It’s on those non-peak days that energy savings can be realized. By pairing efficient pumps with efficient motors and ensuring through system design that they are operating in the most energy efficient manner, buildings will consume less energy.
Although regulations and trends are forcing building designers and managers to find new ways to evaluate and design energy efficient systems, there are strong benefits to using a systems approach in place of older methods.
When components are patched together without considering the entire system, there is a significant risk that the system will not deliver the performance and efficiency gains promised, with components being underutilized or overtaxed most of the time. This can lead to a decline in energy and water efficiency, an increase in operating and maintenance costs and shorter equipment life.
When a systems approach is taken, these risks virtually disappear:
- Energy and water efficiency are maximized.
- The life expectancy of equipment is extended.
- Operating and maintenance costs are lowered.
- Design, procurement, installation, operation, and maintenance are simplified.
Companies that focus on total system design provide engineers with the training and education as well as advanced software tools for product selection and system monitoring to ensure efficiency goals are met. That education and training must include building operators. If a building owner buys the most energy efficient equipment yet the operator doesn’t understand the energy efficient features of the system, they might bypass those features and forfeit energy savings.
Automated building management systems (BMS) common in larger structures also multiply the positive impacts of using a systems approach.
BMS systems enable facility managers to operate buildings to maintain a comfortable environment while closely monitoring the performance of the individual mechanical, electrical and plumbing components that must work together to achieve that goal.
If those individual elements are designed, installed and operated to function as a system, energy and water efficiency can be optimized, predictive maintenance can be performed to extend the life expectancy of equipment, and operating and maintenance costs can be more effectively managed.
With buildings in the education, healthcare, and commercial/office segments ranking as those with the highest penetration of green building, according to the USGBC, a greater focus is warranted on integrated building design principles that reduce energy consumption and increase efficiency in buildings.
Handzel is vice president, product regulatory affairs, and director, HVAC commercial buildings, Bell & Gossett, a Xylem Brand. He is a member of the Appliance Standards and Rulemaking Federal Advisory Committee’s Commercial and Industrial Pumps Working Group.