HEATING SYSTEMS | LOW LOSS HEADERS Separate ways Achieving hydraulic separation through well-designed low loss headers is key for efficient heating and cooling systems. David Palmer and Baxi Heatings Ryan Kirkwood provide detailed design guidance, including a recommended system configuration W ith the evolving complexities of heat generation, and heating and cooling sources, it is important to design and integrate headers correctly into systems. CIBSE Journal, p s p s achieve in practice. Temperature dilution to What is a low loss header? s p impact on, for example, air handling units operate correctly. Alternatively, a temperature rise to the p s, loss device. Considerations for designing a low loss header are: 1. The need for a very low pressure drop along the header to achieve low 2. The relative locations and sizes of the primary and secondary ports Oversizing the primary and secondary flow ports will optimise hydraulic separation and minimise parasitic flow by reducing the injection velocity into the header the load circuit is designed for a return temperature <55C. Optimising hydraulic separation and minimising parasitic as perfect hydraulic separation is not Calculation of parasitic flow Figure 1: Types of header 52 May 2021 www.cibsejournal.com CIBSE May 21 pp52-54 Low loss headers Supp.indd 52 23/04/2021 16:09