Book - School of Science and Technology

578 Hot water supply systemsCisternPumpHeating flowH.W. flowPumpH.W. returnBoilerThermal storeHeating returnFigure 20.16 Arrangement of domestic combined systemwater outflow, at a rate of about 0.2±0.3 litre/s, for a period of 5 minutes followed by arecovery period of 20±40 minutes in preparation for a further similar outflow.Cylinders, indirect cylinders and calorifiersWhilst, in the present context, it is unnecessary to define a cylinder, other than to say thatstandard sizes for such vessels are as set out in Table 20.2, the difference between anindirect cylinder and a calorifier is less clearly established. Early textbooks and cataloguesseem to use the first of the two terms to distinguish heat exchangers for domesticTable 20.2 Capacities and dimensions of direct and indirect cylindersPatternBS ref.Dimensions (mm)Heating surface (m 2 )Height DiameterCapacity(litre) Coil AnnulusDirect 0 300 1600 98 ± ±1 350 900 74 ± ±2 400 900 98 ± ±3 400 1050 116 ± ±4 450 675 86 ± ±5 450 750 98 ± ±6 450 825 109 ± ±7 450 900 120 ± ±8 450 1050 144 ± ±9 450 1200 166 ± ±9E 450 1500 210 ± ±10 500 1200 200 ± ±11 500 1500 255 ± ±12 600 1200 290 ± ±13 600 1500 370 ± ±14 600 1800 450 ± ±Indirect 0 300 1600 96 0.35 ±1 350 900 72 0.27 ±2 400 900 96 0.35 ±3 400 1050 114 0.42 ±Continued on facing page