Ages Of Gazing Into A Coal Fire

Press, Volume CV, Issue 31057, 12 May 1966, Page 13

Ages Of Gazing Into A Coal Fire

How can we explain the fascination of gazing into the cheery glow of a coal fire? Perhaps it is just laziness, or perhaps it is a convenient way of relaxing, but it is still reflected in the demand for modern coal-fired appliances.

For hundreds of years coal has had a very important place in the domestic economy as the main source of heating and firing.

Manufacturers of coalfired appliances have kept pace with the modern trends in domestic heating and firing by the increased efficiency and pleasing appearance of their products. So successful have they been that today coal still has a considerable share in this field, in spite of the impact of other forms of heating.

that less than 20 per cent of the heat was effective in the room. As early fuel engineers developed their knowledge of combustion processes they saw the need to limit air-flow up the chimney. Heat Lost Although excessive airflow ensured adequate ventilation in the room, too much heat was lost up the chimney. Not only were costs increased, but fuel had to be applied too frequently for convenience. So airflow up the chimney was restricted and thermal efficiencies rose. The traditional open fire was still popular, but the demand was increasing for more efficient combustion.

the fire. Efficiencies rose cast-iron surface containing 45 to 50 per cent without any loss of the traditional concept of the open fire. Slow combustion, or closed stoves were developed, being either built into a fireplace or free-standing units, and thermal efficiency increased even more. Glass Windows Most of these closeddoor stoves have windows of heat-resistant glass, through which the cheerful glow of the fire is still visible; thus the fire remains the focal point of the home. More modern developments incorporate a simple form of down-draught combustion, which without detracting from the idea of an open fire, give even higher thermal efficiencies and relatively smokeless combustion. A back-boiler can be fitted to most coal-fired domestic heating appliances to provide the normal hot water requirements and reduce the winter demand for electricity. A recent development is the use of a waterjacketed 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 heating are obtained at a relatively low capital cost without any loss of the traditional effect of the open fire, In Industry Other boiler units are available as the source of heat for a small bore waterheating system, but most of these are used in larger buildings such as schools and for commercial and industrial heating. Units have also been developed, generally on a larger scale, for heating the air in hot furnaces. These units operate silently to produce air either at the appliance or through a ducted system for central heating. These units give no visual, evidence of coal-burning; all that is seen is an attractive steel cabinet.

Crude Open Fire From the earliest days, as man learnt to control combustion and as his knowledge of building increased, he began to produce a crude form of open fire from which the heat was radiated into the room and the products of combustion were carried out through a chimney. This was the form of firing for centuries Whilst it may be only of passing interest to the homemaker, Christchurch leads the field in industrial coal plant, one firm now being credited with the manufacture of the largest New Zealand boilers—two for the Ham University and two for the public hospital’s new boiler plant—and all four are coal fired. Another Christchurch firm now manufactures coal-fired packaged boilers. in fact it became so much a part of our way of life that it gave rise to the saying “home is where the hearth is.” The old type of open fire was inherently inefficient in

Grates were sealed at the front to control the admission of air to the burning coal and the convector type of fireplace was developed. In this the air from the room is drawn into the appliance through grills and heated by contact with the

The coal industry realises that progress in the improvement of appliances is dependent on the development of new ideas and new designs. Coal selling interests have formed an organisation to promote and improve coalburning appliances best suited to New Zealand conditions and coals. This has been prompted by the realisation that coal firing is only as good as the appliance in which it is burnt.

Good Goals New Zealand is fortunate in that its coals have some unique properties such as high reactivity, free burning qualities and low ash content and if used to best advantage are clean and convenient; also, they are better suited to automatic operation than any other coals in the world.