Book - School of Science and Technology

108 Survey of heating methodsReflectorElementGuardFigure 4.11 Electrical infra-red heatermore sightly and easier to clean than infra-red or quartz lamp units, see Figure 4.13,application of these panels is usually confined to washrooms and the like in industrialpremises.Low temperature panelsWhile equipment of this pattern should, strictly speaking, be listed alongside oil filledradiators and other convective heaters, it is convenient to deal with them here.Panels of this type are in some cases faced with a metal plate having an enamel finish,other makes use resin impregnated hardboard or a plastic laminate. The heating elementmay be a conventional form of conductor within an insulating envelope or a polymercoated mesh of synthetic fibre sealed between sheets of polyester film. Many such panelsare purpose made for special applications, one being church heating where a panel is fixedto the rear of each pew seat to provide localised warmth to members of the congregationwithout heating the church fully. Operating temperatures of 70±90 C are usual withratings of 100±500 W.Ceiling heatingIt is necessary to make a clear distinction here between a purpose designed ceiling heatingsystem and the fortuitous heat input from the underside of an intermediate floor slabwhich supports a floor heating system (possibly an off-peak storage type) serving therooms above. It is the former alone which falls wholly within the definition of a directsystem.