Retrofit DHW system operates continuously in condensing mode
With continuing huge gas bills from antiquated DHW equipment in one of its housing projects, Lambeth Living has replaced it with system comprising a Mikrofill Ethos stainless-steel condensing boiler and a Mikrofill Extreme DHW loading system.
The efficiency of the new system is due to the way the loading system enables the boiler to condense continuously whenever it is operating.
A plate heat exchanger provides the interface between the boiler circuit and the water in the storage cylinder. Only when the flow temperature in the primary circuit is sufficient to immediately raise the temperature of cold water drawn from the base of the cylinder to 60°C does the cylinder start to be filled with hot water from the top down.
Because the water in the bottom of the cylinder is cold, about 10°C, the Ethos boiler operates in condensing mode.
When the cylinder is full of hot water, the boiler is shut down.
Only when a sensor in the cylinder detects that a substantial amount of cold water is being fed into the base of the cylinder is the boiler restarted.
There is a dynamic schematic of the loading system on the Mikrofill web site.
