Understanding Primary Secondary Pumping Part 6: 5 Ways to Pump an HVAC System

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By Chris Edmondson

There’s more than one way to pump a chiller or boiler system.  In fact, there are five common approaches, and all but one includes some variation of our topic of late -- primary secondary pumping. 

Variable Primary Pumping

Contemporary systems that do not utilize primary secondary pumping are typically known as variable primary systems.  In this simple design, there is only one set of pumps (chiller or boiler pumps) creating flow for the entire system. 

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Understanding Primary Secondary Pumping Part 4: “What happens when...?”

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By Chris Edmondson

Now that we know what happens when we vary flows and mix temperatures in a primary secondary pumping system, let’s explore these theories in some more realistic scenarios. 

As discussed in a previous blogs, when it comes to primary secondary systems, one of three flow patterns is always in occurrence: 

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Understanding Primary Secondary Pumping Part 3: Avoiding Low Delta T Syndrome

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By Chris Edmondson

Low Delta T Syndrome.  The terminology alone strikes fear in the hearts of anyone involved in chiller plant design or operation.  We know Low Delta T Syndrome is bad.  We know it wastes energy.  The very topic has given rise to countless technical articles and white papers that most of us haven’t the time or patience read.  But take heart because believe it or not, if you’ve read and understand Part 1 and Part 2 of this Series, you already have the building blocks to understand Low Delta T Syndrome.  You just don’t know it yet.

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Thinking Beyond Plate & Frame Heat Exchangers for Waterside Economizing

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By Chad Edmondson

  “What type of heat exchanger is best for my waterside economizer application?”

 It’s a question we get asked a lot.  With the increased requirement for either an air or waterside economizing in ASHRAE 90.1 – 2010, we expect to get asked even more – especially since the DOE expects states to adopt the revised standard into their non-residential building codes by as early as next month.

 U-Factor Versus Real-World-Factor

Conventional engineering logic has always leaned toward plate and frame technology for waterside

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Pump Affinity Laws Are Key To Saving Money in a Hydronic System

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What are the pump affinity laws and why are they so important? 

Pump affinity laws define the mathematical relationship that exists between pump speed, flow, total head, and power consumption.

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