Our most recent video is an explanation of how flow levels inform HVAC optimization.
Many of today’s buildings rely on HVAC systems that were oversized on installation to address uncertainty in cooling and heating loads. Unfortunately, many building occupants still experience discomfort, even with the extra capacity in HVAC systems. To make matters worse, most HVAC systems operate inefficiently and this poor performance goes unnoticed by building owners and operators. Without automated maintenance alerts, and regular recommissioning, most buildings will experience a drift in HVAC performance efficiency of 10-30% in just 2 years.
Addressing this issue is more than just a cost control challenge. It’s a sustainability issue. Buildings are responsible for over 39% of energy-related Greenhouse Gas Emissions. Armstrong uses a unique approach to help building operators improve efficiencies and reduce costs. The flow rates in your HVAC system are an excellent indicator of how well it operates and where problems may be lurking. Without information on system flow, it’s difficult to diagnose and optimize performance. If accurate flow information is available, the picture changes entirely.
In any chilled water system, knowing the cooling load is the best starting point. Cooling Load in a building can be calculated by multiplying the system flow rate by the change in process temperature - usually expressed as delta T.
Traditionally, HVAC systems in buildings were designed to operate on single process temperature setpoints. But this temperature setpoint design approach reveals a weakness. The building operator is often unable to identify progressive degradation hidden in the HVAC system. Without flow data, degradation issues are identified only if the temperature setpoints in the system cannot be maintained. By then it’s too late, and after months of inefficient operations that could have provided a warning signal, occupant discomfort becomes a problem.
Accurate flow meters are rarely in place in HVAC systems and are almost never installed on all of the circuits necessary to calculate loads or observe heat balance. Particularly, in a cooling tower or condenser circuit where water circulates between the chiller and the cooling tower, the efficiency of heat rejection is rarely known or even tracked. Even for those rare cases where a flow meter was installed, if it is not maintained and re-calibrated, flow data becomes unreliable. As a result of this low accuracy, undetected system performance drift is common.
But today building designers and operators have a new source to gain flow data. Flow data from an Armstrong Design Envelope pump supports innovative diagnostics and provides clues for new optimization approaches. It also provides back-up information for system performance commitments and condition-based maintenance programs. Flow data can provide valuable insights at every stage of your building life cycle and can have a direct impact on occupant comfort, energy savings and equipment availability.
Accurate flow data from both sides of a heat transfer device enables a clear assessment of an HVAC system, long before restrictions in flow cause problems in performance and occupant comfort.
Understanding flow and changes in flow rates is a key first step in building a true load profile of the chiller and the heat rejection process equipment in an open circuit or a closed circuit.
Armstrong provides a host of higher-level solutions that leverage accurate flow data from Design Envelope pumps to optimize system performance and detect degradation. These solutions provide performance persistence and support efficiency through their own continuous improvement processes.
We refer to these as our Active Performance Management Solutions. Active Performance Management relies on analytics that are made possible by flow data and heat balance models of a system. Our Active Performance Management services deliver system-wide HVAC efficiency for better building performance, lower operating costs and lower maintenance costs.
As a building owner/operator, you can reach your sustainability goals and improve occupant comfort at the same time. You can also improve Building Lifecycle Performance and achieve better business results through informed investment decisions. And it all starts with an understanding that flow informs.
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