AN ASSET TO NELSON

Nelson Evening Mail, Volume 76, 17 October 1941, Page 3

AN ASSET TO NELSON

WAYS OF USING SOLAR ENERGY EXAMPLES IN OTHER COUNTRIES) QUOTED Places with a sunny climate like) Nelson’s should consider ways of using the solar energy, as for example in hot boxes, said Professor J. S. Tennant in an address to the Nelson Rotary Club yesterday. All who had travelled would agree that New Zealand was a wasteful and extravagant country, in regard to natural resources. He was taking the • question of sunshine as one of them, said the professor. It was a very ) appropriate subject for a place like Nelson. Countries like New Zealand, Australia, and South Africa had apparently ' done nothing in the matter, whereas Switzerland, France, and particularly I North America had given a lot of ; attention to the subject. In fact in ■ I America the Smithsonian Institute subsidised research in all matters dealing with the subject of solar energy. If sunshine could be turned into work the average of all countries was something like 5000 h.p. per acre, roughly one h.p. per yard. That tremendous amount of power was to a considerable extent wasted. All heat was radiated back again with the exception of what went into the growth of plant and (animal life and into lifting water to a ' higher level. Heat power was very I difficult to use to any great extent, j The most efficient steam engine could [ only use and develop about 11 per cent ;of the amount of energy released in • the burning of coal. The gas engine j was a little more economical, its, efficiency being about 20 per cent.! Solar engines had been devised, and I these had been able to work up toj I about five per cent efficiency. The sun’s energy had always been I jthe object of interest by scientists and l | others, and the burning glass was | probably the most ancient instance historically. Professor Tennant referred; i to several early experiments, mentioning Herschel who collected his friends : | one mid-winter day in 1830 and gave! i them a dinner which he had cooked in i a hot box which ho had prepared and . [ managed to insulate. It produced a | temperature of 217 degrees. A sunj power plant had been established near | Cairo, being used to pump water to irrigate the land. Sunshine plants were ! particularly suited for that sort of j thing. It generated about 50 h.p. A sunshine cooker was devised in one of the Californian observatories. Oil, passed through a copper tube contain- 1 ed in a glass tube into an insulated oven and back into the tube. By means of heavy oil which did not boil at such j a low point the heat was raised to 175 degrees Centigrade. It did all kinds of cooking in the daytime and retained enough heat to bake all the bread dur--1 ing the night, though the nights were cold. It was all a question of insul ation, and the insulation of the vacuum was the best. The speaker said that the hot box 1 was extremely simple and would be quite effective in Nelson, which had one of the highest sunshine totals in [the world, higher than California’s. In, ■Nelson there seemed to be 70-160 sun- ; less days. The average in California was 200 sunny days, so Nelson could j beat that average. Speaking on its domestic usage Pro-: fessor Tennant said that in California' and Florida in the last few years the) whole matter had been made quite a 'commercial success and there were a large number of private installations of water heaters. These heaters worked I out at something like four dollars per ! gallon.