Is the widespread application of low pressure loss distribution headers in UK heating systems wreaking havoc with the real life-cycle impact for the sake of a 'standard' design?
Simon looks back at how low loss headers were originally applied in the USA to reduce chilled water system pumping energy whilst maintaining near constant flow through chillers. The technique crossed the Atlantic where hydraulically separated boiler and heat distribution (primary/secondary) pumping circuits enabled compact boilers, requiring high minimum flow rates, to serve variable flow distribution circuits.
This set up is still popular but few designers consider the additional number of circulators, additional pumping energy and reduced efficiency due to mixing of return water and reduced deltaT across the boilers. Current boiler technologies mean there are opportunities to apply variable flow heat generators to minimise lifecycle costs.