Building Services Engineering 5th Edition Handbook

Heating 87
employed in large buildings, where the capital cost can be offset by reduced energy consumption
and personnel savings.
Heat emitters can be classified as follows.
Radiators
Heat emitters providing radiation come into this group. A steel single-panel radiator emits about
15% of its total heat output by radiation and the remainder by convection. Radiant output from
multiple panel and column types may be a lower percentage of the total. Electric, gas and coal
appliances produce large amounts of convection and are partly convectors.
Types of radiator are:
Hot water: single-, double- or triple-panel column radiators, skirting heaters, recessed panels,
banks of pipes.
Electricity: off-peak storage heaters, radiant appliances, convectors, radiant ceiling systems.
Gas, coal and oil: radiant appliances; Fig. 4.1 shows a gas-fired domestic radiant and fan convective
appliance often suitable for the elderly or infirm even when central heating provides air
heating around the occupants. Air heating alone is not always enough warm for very sedentary
residents.
The main characteristics of radiant, also providing convective heat output, appliances are
as follows:
Steel single panels: Neat appearance, high heat output per square metre of surface area, easy
to clean, narrow.
Steel double panels: Greater heat output per square metre of wall area used, difficult to clean,
protrude into the room, more costly. Anti-corrosion chemicals needed in heating water for all
steel materials.
4.1 Gas radiant and fan convector room heater.