radiator_flow_temperature

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Work out the flow temperature a heat pump must produce to heat a room through a given radiator, and the resulting MCS Heat Emitter Guide star rating, following section 4 of MGD 007. This is the calculation that decides whether a heat pump will be cheap or expensive to run. A heat pump's efficiency falls as the water temperature rises, by roughly two to three per cent per degree, and the temperature it must produce is set by the radiators, not by the machine. Supply the room's design heat loss in watts, from a room-by-room calculation, and the rated output of the radiator in that room. British catalogues normally quote at a mean-water-to-air difference of 50 K; if yours quotes 60, say so and the figure is restated. The result gives the oversize factor, which is the radiator's output at 50 K divided by the room's heat loss, and converts it to a required flow temperature through the BS EN 442 output law. Star ratings run from 0 to 6, one star per five degrees of flow temperature, with six stars at 35 degrees. Run this for every room. A house runs at the flow temperature its worst room demands, so one undersized radiator sets the running cost for the whole house. Method from MGD 007. These calculators follow the published MCS methods, for understanding a system and checking a quotation. Anything that gets installed still needs a design and a site survey from a certified installer.