Coal For 200 Years

Press, Volume CV, Issue 31057, 12 May 1966, Page 12

Coal For 200 Years

(By K. C. THORNHILL Fuel Engineer, Mines Department.) Coal Is the only fuel known to exist in New Zealand, in quantities large enough to last at least 200 years. The West Coast, for example, has known reserves of 50 million tons, with 40 million tons indicated, and 57 million tons inferred. The present consumption for Canterbury is about 300,000 tons a year, split more or less evenly between industrial users and domestic users. The industrial user is now using the coal efficiently, but the domestic consumer still tends towards the open fire of about 15 per

cent efficiency. A modem domestic heater, using coal, can operate at somewhat better than 50 per cent efficiency, hence requiring only one-fifth the fuel to provide the same amount of heat. The following table illustrates the cost per kilowatt of heating a room, the unit chosen being the kilo watt, as the single bar electric heater is usually 1 KW and is easy to visualise. Open Fire (plain stool bottom) .. I.Bd Open Fire (improved stool bottom) .. l.ld

Convector type open fire .. o.Bd Space heater .. 0.7 d Central heating .. 0.5 d As can be seen the operating costs cover a fairly wide range, and it must be that the warm cheery glow of the open fire is its attraction and' certainly not its cost. However, the fitting of a properly sealed-in stool bottom with built-in draught controller can make the cost comparable with electricity, or the installation of a builtin convector type of fireplace make coal the cheap-

est fuel for home heating. Space heaters are, of course, an engineer’s choice. Cost-conscious people interested in even heat and low running cost will install such appliances which usually are best fitted when building, rather than after. Finally, there is full-scale central heating whereby the whole of the house is kept up to temperature by a warm air or low pressure hot water radiator system. All draughts and cold spots are thus eliminated.

The main trouble with complete central heating is that once the open fireplace is removed, the focal point and indeed the “meeting point” of the living room is lost, and this led to the introduction of a new system of heating from the open fire. This method consists of a high efficiency “wet back,” capable of supplying hot water to radiators in the hall, bedrooms and, most important the bathroom. It provides all the hot water for washing up and baths that can be desired.

A recent experiment was also carried out with a wellknown space heater which can normally put warm air from the back of the heater into a dining room. On this occasion however, the heating coil (normally for domestic hot water) was connected to 20 sq ft of radiator surface in the hall with excellent results.

The coal industry has a number of experimental units under trial at present, in particular experiments with gravity feed and with down-draught combustion. The object of the trials has been to produce appliances that need stoking once a day, burn smokelessly on the down draught principle, and lend themselves to simple automation. The coal industry also offers a service to the smallest house or largest factory, and has fully-qualified chartered fuel technologists in each of the four main centres.. Whilst these engineers do concentrate mainly on large industrial consumers, a new organisation is under review with the special requirements of the domestic trade in mind.