Backyard genius: Pumped up for energy savings at the coal face

A Danish firm has taken up Peter Thompson's water heating design for dairy sheds. Picture / Glenn Jeffrey

Perish the thought, but if it was illegal to use technology we didn't understand, we'd likely be back in the stone age before you could say, "three-phase digital transponder".

Take heat pumps, for instance. "People are mystified by them," says Peter Thompson - who isn't.

"There's nothing magic about heat pumps." Imagine pumping up a bike tire, he says.

"After a while, the connector gets hot. Well, that's heat from the air - because there's some heat in everything - plus energy from the muscles in your arm."

Now, replace muscles with motor and you've got a heat pump.

"They do not make heat. They take low-grade heat and factor it up into a useful higher temperature. They're concentrators of heat. Nothing more."

Peter should know. His heat pump produces the highest temperatures ever. And all thanks to Glasgow grass.

No, that's too glib. A huge amount of "quiet, patient research" has gone into this, but an icy lawn did get it started.

Peter "went to sea" in his younger days as a marine engineer and met his wife while studying in Glasgow.

After they returned to New Zealand, his father-in law sent a clipping about a chap who had "defrosted" his 250-year-old house with a home-made heat pump concentrating heat from 1000ft (305m) of copper pipe under the lawn.

"I've got to do something with this," Peter thought. But he wanted a pump capable of generating enough heat for industry to use.

And he has one, after 25 years.

Peter decided at the outset not to tread an already trodden path. Existing methods would give him existing results, and he didn't want 50C, he wanted 100. So he taught himself what he needed to know and "concentrated on reaching my target".

Which meant building his own pilot plant (with kiln because he saw timber-drying as a use). The key is a unique heat exchange section. "That's the heart of a heat pump, and my section processes the available heat differently."

He'll say no more on this, preferring to discuss the benefits of his invention.

"If all of New Zealand's milk production was pasteurised by heat pumps instead of boilers, there'd be a 96 per cent reduction in carbon dioxide released into the atmosphere, and a tremendous reduction in electric power - something like 750 megawatts per annum."

Even so, knocking on some important doors produced no response.

"If it weren't for my own enthusiasm, I wouldn't have got anywhere."

But finally, he did get somewhere. Specifically, the New Zealand office of Danish company Danfoss decided they would manufacture their version of his pump, the Mahana Blue Water Heating Unit. Designed for dairy sheds, it reheats waste water to 85C for post-milking washdowns - and cuts power use up to 60 per cent.

That's just the beginning. "I want New Zealand - as in all of us - to feature in this above everything else.

"The US Department of Energy has printed some information about what we're doing and I've just heard from a Swedish Energy Conservation wanting to know what the heck's going on, so the word is getting around."