How does a heat pump work?

We get a lot of questions on this, so here's the answer. A heat pump does more or less what it says on the tin: it pumps energy from one place (usually outside) to another (usually inside). It turns out that you don't need to work very hard to move large amounts of energy around in this way, so heat pumps are quite efficient. 

The other thing people ask is how you can heat a home to 18 or 20 degress when the heat source, in the air or ground outside, say, is only 4 or 5 degrees. Perhaps the easiest way to think about that is just that the heat pump is also an energy concentrator of sorts - it is harvesting energy from a lot of air (or ground) and using it to warm up smaller amounts of air (or water) in your house.

What's perhaps most interesting about this is the source - How Things Work - The Universal Encyclopedia of Machines - first published in 1967. A reminder that we have been around the energy-saving block at least once before, so far (it has to be said) with no success. Have another look at this year's Godkin lecture by John Deutch of MIT for a first hand account of how frustrating that is for people who were involved in this sector in the 1970s.

Open publication - Free publishing - More refridgerator

PS I am not sure who has the copyright to these pages. I have looked for the original publisher online (Granada) but they are long gone, it is now 40 years since this book was published. There is a US website called How Stuff Works that has a useful (and somewhat more modern) page on heat pumps.

PPS heat pumps are not the best solution for many houses. The typical savings are often not better than a Band A condensing boiler running on mains gas, and the performance (in terms of comfort levels) can be poor, especially in large uninsulated homes with radiator-based central heating.

A useful thing to do with Carbon

In case anybody missed it, two smart guys from The University of Manchester just got a Nobel Prize for Physics. The prize was for their work on graphene, a material composed of a single layer of carbon atoms in a chicken-wire formation. (Chicken wire - that's a technical term, by the way.)

Graphene is 200 times stronger than steel, if you scaled it up to the thickness of cling film and stretched it over a cup of coffee, it could hold up the weight of a truck bearing down on the point of a pencil.

"Carbon, the basis of all known life on earth, has surprised us once again" said the Royal Academy.

(PS Did you notice that one of the recipients also won The Ig Nobel Prize - for levitating frogs in a magnetic field? I kid you not. The image below is for real, you can download the research paper here.)

100 years to get off the planet

Worth watching this 2 minute video from Stephen Hawking and the Big Think. Hawking says: "If we are the only intelligent beings in the galaxy, we should make sure we survive and continue ... we have made remarkable progress in the last 100 years, but if we want to continue beyond the next 100 years, our future is in space." Wow.



There is more background on the Big Think website, which has been publishing 'one radical new idea' each day this month. You might also want to have a read of Big Idea #16 (Parents Don't Matter), or #1 (Drug our Drinking Water).

High Impact, Low Frequency?

The BP oil spill has got us all thinking about low frequency, high impact events. But some people have been thinking about these things for quite a while, including the team at NERC - the North American Electric Reliability Corporation. Who knew such an institution even existed? Their job apparently is to worry about unlikely events that would be really, really bad if they ever came about.

The latest NERC report includes a detailed section on geomagnetic storms:

The analysis indicates that the [geomagnetically induced current] in over 350 transformers will exceed levels where the transformer is at risk of irreparable damage...  Such large scale damage could lead to prolonged restoration and long-term chronic shortages of electricity supply capability to the impacted regions, arguably for multiple years.

In other words, a really big storm could roast enough components (70-80% of transformers in some states) to put the lights out for years. A version of this event happened in March 1989 and knocked out parts of the Canadian grid for most of a day. But since then, the grid has been developed in ways that make it more vulnerable than before: essentially, higher voltage transmission means geomagnetically induced currents can travel further and do more damage.

From a different angle, we could perhaps get a similar effect from a high altitude nuclear explosion. Here's a photo of the last time we had a go at one of those. This one was 400km in the air but the electromagnetic pulse was enough to blow out the streetlights in Hawaii, 1500km away.

(This is the 1962 Starfish Prime explosion.)

1 in 3 Brits say climate change is bunkum

The BBC published a poll in February showing 25% of British people think Climate Change is not happening. Another 10% believe it is happening, but it isn't man made. So it's official: 1 in 3 Brits do not believe in man-made Climate Change.

Well, I for one am one of the other two. I doubt I could express my reasons as well as Peter Gleick in his letter to Science magazine this month, signed by 250 members of the US National Academy of Sciences. Sensible, straightforward stuff.




Source: http://news.bbc.co.uk/1/hi/8500443.stm 

Can we make CO2 into fuel?

Here's some interesting science. It may be possible to turn CO2 into methanol, a useful fuel. There is a good article about this in the New Scientist and you can find a summary of the science here.