Buildings – big and small, old and new – are collectively the largest consumers of energy worldwide. Within each individual building, the heating, ventilation and air-conditioning (HVAC) systems consume the most energy. An even closer look at a building’s various HVAC systems will reveal that it’s the building’s central chilled water plant that is the biggest energy glutton.
Due to this ongoing challenge, the central plant is receiving growing attention as pressure builds to increase plant efficiency within buildings. This is especially important as building owners are seeking ways to meet government mandates for energy efficiency and strive toward green building certification requirements such as Leadership in Energy and Environmental Design (LEED®) standards.
A holistic approach called Central Plant Optimization offers a way for central plants to reach and sustain their high-performance, high-efficiency potential. When implemented holistically across the lifecycle of an HVAC system, Central Plant Optimization can deliver energy savings of up to 60 percent.
Thinking holistically about HVAC
In the past 25 years, HVAC equipment has become much more efficient. In some cases, the efficiency of HVAC components has improved by as much as 40 percent. Yet, these recent improvements cannot be expected to continue over time. The industry is quickly approaching its limit in terms of how much efficiency can be expected from individual HVAC components.
Even the most efficient commercial HVAC systems do not meet their promised efficiency over time. Performance drift occurs because the central plant is traditionally operated and maintained as a series of disparate pieces of mechanical equipment. In reality, today’s high-efficiency HVAC components are designed to work their best as part of a networked, interrelated system. In other words, the sum of the parts does not equal the whole.
Today, engineers and building owners need to look beyond the component level to reach increasingly aggressive energy efficiency goals. The focus has begun a shift towards a broader, holistic approach to achieving ongoing energy savings within buildings. Looking at plant design and operation as a whole will drive the efficiencies that minimize operating costs and reduce environmental impact.
Taking the Steps to Optimization
Central Plant Optimization is a process that considers the lifecycle of a central plant. This encompasses everything from infrastructure design and component selection to measurement and maintenance of the central plant.
For example, the foundation of an optimization plan is a well-designed system infrastructure that offers the necessary flexibility across the lifecycle of the system. Beyond this, it is important to choose the right HVAC components that will perform efficiently in real-world operating conditions. Following best practices to apply and operate this equipment properly is also a must.
Today’s networked optimization software takes advantage of building automation systems to maximize central plant efficiency. This software no longer needs to be custom-built to the building application. Rather, today’s technology is standardized and scalable for any building application for both new and existing buildings.
The role of building maintenance is also critical to optimization. Facility maintenance now has the potential to be predictive because technology allows issues to be identified before they become more problematic. Measurement, verification and management of real-time building data enable systems managers to find and address system faults quickly and efficiently.
Building owners and operators have the biggest opportunity to realize savings where the facility consumes the most energy. Central plant optimization provides the potential to achieve and sustain ongoing energy and cost savings, which ultimately helps impact any organization’s bottom line.
Written by Dave Klee, Johnson Controls
Dave Klee is Director of Channel Marketing & Strategy for Johnson Controls. He leads programs and initiatives for the HVAC Systems business in North America, for HVAC products, equipment and building automation.