Variable Primary versus Primary/Variable Secondary Chilled Water Pumping
What You Will Learn
Within the broader context of design decisions, the choice between Variable primary flow and Primary/Variable secondary seems almost inconsequential. However, the differences in operating practices and efficiencies between the two types of systems matter. Those aspects, combined with the short and long-term cost implications, make this an important design choice for any building. For a careful comparison, plus the latest info on the merits of each configuration, and an explanation of industry-leading variable speed technology.
Key topics include:
- Opportunities in chilled water plumbing
- Simpler and more reliable installation
- Reduce plant costs with parallel pumping
- Active Performance Management to maintain maximum operational efficiency
Key questions answered during the webinar:
- Is it necessary to have a three-way valve in the primary/secondary setup to prevent the secondary pump from deadheading?
- Are there any temperature limitations on the fluid because of the inbuilt VFD?
- If the actual pressure loss is different from the design, do the sensorless pumps need to be adjusted to match the design flow or is it automatically adjusted?
- For variable primary-only configurations, one of the limitations is maintaining multiple different temperature loops. What is an efficient way to manage this without adding pumps?
- What is an auto-balancing flow valve and how does it work?
- In a constant variable primary and secondary piping system, should there be a check valve installed in the bypass line to prevent secondary water from bypassing the chillers?
- Can we install a two-way modulating valve at the coupler line and can it help in terms of energy savings?
- What does Armstrong consider a system with a single zone versus a multi-zone?
- What is typically the lowest speed we can operate at with the VFD?
- Do design envelope pumps need an inertia block?
- Is pump manager service standard with the pumps or is it optional?
- For those old-school designs, do you recommend a check valve in the decoupler lines between primary and secondary systems?
- What is the difference between a decoupler and a bypass line? Do we need any modulating valves in the decoupler line?
- Can we use a secondary pumping system in open weather conditions?
- What is your point of view on a system that does not have primary and secondary circuits?
- Can a small design envelope pump replace the modulating valve in the bypass line?
- For the variable primary system, in the case of multiple chiller installations, is there any difference in savings if we have a fixed-speed chiller versus a variable-speed chiller?
- What is the purpose of an expansion tank in the system?
- In a primary only system, is a two-way or a three-way valve more effective?
- What are the benefits of getting an IPS 4000 pump controller used to control primary design envelope pumps when the chillers are at constant speed?
- What kind of system is ideal for controlling the low delta T syndrome?
Product Solutions of Interest:
Heating and Cooling
Related Case Studies
Dow Kokam – An Industrial Facility Installation
Ventus at Metrogate – A Residential Facility Installation
Commercial Towers – An Energy Upgrade Installation
Webinar topics you may also like:
Piping Design for Variable Flow Hydronic Heating Systems
Better Together: Hydronic Heating Systems and Intelligent Variable Speed Pumps
Self-Regulating, Variable Speed Fire Pumps Better, Simpler, and More Cost Effective
Back to Basics: Variable Speed Pumping and Sensorless Control