Primary Secondary Tertiary Systems for High Delta T Hydronic Heating Systems
Last week the MMM article topic was primary secondary piping basics. Today we will describe some terms before looking at a more complex system.
In our example above the purple piping is normally called the “Primary System”. This is the system with the boilers and boiler circulating pumps.
The red piping is normally called the “Secondary System”.
The blue piping is normally called the “Tertiary System” This can be a coil with pump or other terminal out in the system. It may also be a series of secondary-tertiary loops in the boiler mechanical room. The tertiary system could contain multiple coils or terminal units.
The green piping is “The common pipe”. The pressure drop in this pipe is “common” to the pump head calculations of the two adjoining systems. Systems are designed to keep the pressure drop in this pipe very low.
The red pipe with the arrow is referred to as the “Bridge”.
Next week we will discuss having secondary and tertiary loops with different supply temperatures and begin the discussion about changing delta T.
High Delta T Hydronic Heating Systems Series:
- Part 1: Primary Secondary Tertiary Systems for High Delta T Hydronic Heating Systems
- Part 2: How to Increase the Delta T in Hydronic System Design
- Part 3: Increasing Delta T and Lowering Water Temperature in Hydronic Heating Systems
- Part 4: Maximizing Delta T in Boilers
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