HVAC engineers

Primary & Secondary Pumping Systems As we all know, a system with only primary pumping at a constant volume will operate inefficiently for most of its lifetime. The primary-secondary system solves one problem in the older system: high pumping energy consumption. But how does a primary-secondary system save pumping energy? First, the system starts by separating the piping into two sides: production (primary) and distribution (secondary). The primary side contains the chillers and the primary pumps, while the secondary side contains the secondary pumps and the cooling units (FCU/AHU). During times of partial load, which make more than 95 % of operational hours, the cooling coils won't be needing the same flow rate of chilled water because the heat load is less. This is controlled by a 2-way valve which regulates the flow of chilled water through the cooling coils based on the room's temperature. To save costs and eliminate the need for bypass lines around cooling units, the s...