Modern Coal Appliances &

Press, Volume CIX, Issue 32036, 10 July 1969, Page 13

Modern Coal Appliances &

In modern-day domestic heating, solid fuels are thought to have been left out of the tbcc. We tend to condemn the old inefficient open fire, which basically has not for centuries; we ignore the developments in new appliances and the improved installations. As in all developments, modern techniques have brought wonderful changes, and there is no more reason for damning coal or the original open fire, than there is for basing our conception of motoring on the perambulations of the 1910 automobile.

fContribut.4) There ii no doubt that coal-fired appliances are less convenient than some of those using other fuels. Even with the more sophisticated and nearautomatic domestic solid fuel appliances, the charging with fuel and removal of ash cannot be avoided completely. However, where cost is the important item, coal comes back into the reckoning—the basic fuel cost is low and with reasonably efficient appliances, the price of the useful heat can be the

lowest obtainable. It is very important to record that last winter, when it was not very cold, coal suppliers and appliance manufacturers rejoiced in a better year than they had had for a long time. They attributed this to the increased price of competitive fuels. Advantages f Solid Fuels There are many real advantages in domestic solid fuel firing, as listed below: Solid fuel appliances can use a variety of fuels available from various sources. They can use also all these fuels and they can use also mixtures of them, at different times to satisfy different conditions. The fire is a convenient method for the disposal of rubbish and for generating some beat from this waste product.

There is a wide range of appliances and of types of appliances available from several manufacturers as described later. The choice of a domestic appliance is often a personal one, involving all sorts of factors—such as price, installation cost, running costs, frequency of use. duration of operation, the design of the room, and simply the personal preference and prejudices, tastes and habits.

The fire provides a degree of ventilation as a result of air pulled through the fireplace, the room . and the house. The importance of this feature is becoming more and more apparent, as modern houses built without a fireplace are beset with troubles due to mould formation and mildew caused by a lack of this ventilation. The fire can provide functions other than that of heating a room, the most common one being the heating of hot water for domestic supply and even for a hot water radiator system. The fire has some indefinable attraction, providing a focal point in a room, the cheerful glow providing some friendly comfort and company.

Perhaps the most important feature is the individual personality which can be given to a room by the surround of brick, decorative cement bricks, decorative schists and stones. Most have, at some time, been impressed by a complete wall of stone, offering variation and uniqueness in room design, so important in the modern stereotyped house. Domestic heating in The original open fire was Inherently an inefficient appliance—in many cases, less than 20 per cent of the heat of the fuel ended up as effective heat in the room. Gradually the grandfathers of the grandfathers of today’s technologists learnt about the combustion process. They learnt the need to limit the quantity of air flowing up the chimney although these excessive air flows ensured adequate ventilation and prevented any stuffiness in the room, it meant that too much heat was being carried from the fire up the chimney. Low efficiencies meant not only an increased cost of working, but they brought the need for more effort in the frequent tending of the fire. So fireplaces were developed tn which the flow of air up through the chimney was restricted and the thermal efficiencies rose.

Still the traditional form of the open fire persisted, but always there was the demand for more efficient combustion grates were sealed at the front to control the admission of air into the burning coal and the convector type of fireplace was developed in which the air from the room was drawn into the appliance through grills and heated by contact with the cast-iron surfaces which contained the fire. Efficiencies rose to 45 per cent-50 per cent without any loss of the traditional concept of the open fire. i Slow-combustlon stoves, or closed stoves, were developed, either built into a fireplace, or as freestanding units, in which thermal efficiencies increased even further. In most cases, these closed stoves had windows of heat resistant glass—the cheerful glow of the fire was thus

visible, and the fire retained its charm as the focal point of the room. Modern developments incorporate a simple form of down-draught combustion, which, without detracting from the idea of an open fire, gives even higher thermal efficiencies and relatively smokeless operation. With most domestic appliances a back boiler can be fitted to provide the house’s normal requirements of hot water and to reduce the winter demand for electricity. A most interesting recent development which is evoking a great deal of interest is the use of a water - jacketed fireplace from which the hot water is pumped through a small bore system to radiators throughout the house. In this way, the benefits of central beating are obtained at relatively low capital cost, again, without any loss of the traditional effect of the open fire. Again, other units have been developed, generally on a larger scale, for the supply of hot air. These units operate silently to produce hot air either at the appliance or through a ducted system for central heating. In these units, there is no visual evidence of coal burning as there is in most domestic coal appliances—in fact, all one sees is a steel cabinet which, from its appearance, might just as well be gas-fired or oilfired.

The coal Industry has recently established a deferred payment scheme whereby appliances can be purchased under hire purchase from recognised suppliers. These hire-purchase arrangements are similar to those which are commonly available with appliances fired with other types of fuel.

The gradual development in coal firing has changed the face and the shape of coal-fired appliances. The coal industry realises -that progress in the further development of improved appliances is still. dependent on the continual evolution of new ideas and of new designs. On this account, coal-selling ‘interests in New Zealand have now formed an organisation to promote, in every way possible, the installation of coal - burning appliances which, being suited to New Zealand conditions and to New Zealand coals, will produce an increase in coal consumption. This organisation, Coal Appliances Incorporated, will foster the continued production of appliances already available, but its main function will be in promoting new appliances or those which have not yet become properly established.

It is realised that New Zealand coals have rather unique properties, and, if full advantage is taken of these properties, these coals lend themselves to dean and convenient use, and to automatic control probably better than any other coals in the world. Coal Appliances Incorporated will promote the use of improved appliances by developing new ones and by testing and modifying those available overseas which promise to suit our coals.