Book - School of Science and Technology

Equipment for room stores 133Table 5.9 Storage fan heaters ± typical particulars (Stiebel Eltron)Input rating (kW)Item 2 3 4 56Performancecharge acceptance (kWh) 14 21 28 35 42static loss during charge (kWh) 1.75 2.25 3.25 5.15 4.4Outputstatic loss by day (kWh) 6.25 9.85 13.35 14.9 18.6available for control (kWh) 6.0 8.9 11.4 14.95 19.0Dimensionsheight (mm) 640 640 640 640 640width (mm) 584 775 965 1150 1340depth (mm) 240 240 240 240 240Weightin situ (kg) 90 128 165 200 239Fansnumber 1 1 2 2 2power, each (W) 20 20 15 15 15Noise levelrating (dB(A)) 34 34 35 34 33spacings which will vary with the loading and with the final floor finish: the centres maybe between 100 and 300 mm and are sometimes varied across a floor, being closer at theperimeter than in the centre. Alternative methods of laying are used:. Rewirable systems where the elements are laid within tubes which run across the floorbetween accessible trunking, using silicone rubber or glass fibre insulated cables.. Non-rewirable systems where the elements are buried directly in the structure, usingcopper sheathed mineral insulated or cross-linked polythene insulated cables.Cables are provided cut to length by the manufacturer to suit the required loading and arefitted with cold tails for connection to the supply.Of prime importance to the success of a floor warming system is the provision of ahigh standard of insulation below and around the floor structure, a 50 mm thickness ofexpanded polystyrene or other equivalent material is adequate and this should be placedas shown in Figure 5.6 wherever this is practical. It has been emphasised earlier that thepositioning of the horizontal insulation layer has a significant effect upon the storagecapacity of the floor.Most types of floor finish have been used with warm floors but it is necessary to ensurethat any adhesives involved when laying linoleum and some types of thermoplastic tile aresuitable for the surface temperatures estimated.Control of room storesRoom stores are normally provided with a charge controller, set during the previousevening to regulate the energy input overnight. Since, however, it is the weather of themorrow which needs to be sensed, the results produced are somewhat inexact. In itssimplest form, as incorporated in most types of commercial storage radiator, such a