Heating water with the sun

Press, Volume CXIII, Issue 33277, 14 July 1973, Page 11

Heating water with the sun

< By

JEAN LAWRENCE

There has never been a more opportune time than now to think about economising with electricity. And economy, like any other reform, starts with the individual.

Here then is a personal testimony to one method—solar water heating.

For some years we had been interested, in a purely theoretical way, in solar energy, after reading about experimentation in Australia. So it was inevitable that we should investigate its practical aspects when the occasion arose. When an adequate supply of water became available to our cottage in the Marlborough Sounds, we wanted to install a shower and bathroom facilities.

Electric power was already laid on, but to heat our water sufficiently, a major job of rewiring would have been necessary. Also, we felt there was something almost aesthetically satisfying about harnessing natural elements. We read, debated and considered. And four years ago we started living with the sun.

The plant itsqlf was supplied and installed by a heating engineer in Picton, who was an enthusiast and something of a specialist. Large and heavy The installation was not without its difficulties, because of the position of the cottage and the necessity of hoisting the large, heavy structure on to the roof of the two-storey building, which had been built years before.

How simple it would be with a new home in the course of construction.

I suppose most people know the principle of solar heating, whereby water in copper pipes is heated by the concentrated rays of the sun. The “collector” looks rather like an outsize cucumber frame with glass covering the network of copper pipes; which cross from one side to the other in a parallel maze over the black bottom of the frame. Ours is raised on a northwest angle to catch the maximum sunlight, which is very concentrated, as the house is set hard in the hillside. However, this is just fortunate geography and would not be essential for efficiency.

The copper pipe leads to the storage water cylinder,

heavily lagged and encased in a zinc jacket which stands close by on the flattish roof

The installation was made in February in maximum summer weather, and the collector had been in position for only about 15 minutes when 1 was called up to the roof to inspect it. The pipe was still not connected to the cylinder, and the water that trickled out of it was already too hot to touch.

It was obvious that it was going to be efficient enough to connect it to the kitchen as well as the bathroom and shower. Hot shower

Since then we have scarcely needed to use the electric water heater for the kitchen in summer, and the shcwer becomes so hot that we often have to turn the mixer down to the “cold” slot. Our electricity accounts are very low* in fact often under the “guarantee” amount.

The heat generated obviously depends on the weather and the amount of light. To our surprise light without sunshine seems to heat—thus, mild days with little sun, but diffused light will heat the water quite effectively.

As this is only a week end

cottage, an electric "boostc is not necessary, but tl could be added for winter one spent longer perio there. In these four years the has been no need for ma tenance. I understand that sol heating is used for warmi swimming pools both Australia and, in rater cas New Zealand With th dry, clear climates, the e and north coasts of the Soi and North Islands wo seem to be particularly si able areas for solar healit though it is more than lik that most districts of N Zealand could profitably it. It is probably the clai of the air that makes th so successful in Marlboro’ and Nelson.

Were we to build again town we would definitely stall a solar heating pl probably a laiger unit wil booster attached. It woult cheaper to install with building under construct I am convinced that initial cost would be rei over the years by electricity bills. But perhaps ntoie im tantly. we would have satisfaction ot knowing i in our own small way, were helping to keep Zealand's lakes and ti safe from exploitation.