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Tuesday, 8 January 2008

Pipes and Pumps, part 3

I've recently stumbled across the controversial figure of Amory Lovins, a high-profile American advocate of radical energy efficiency improvents through integrative design, improved technology and really obvious (once they're pointed out to you) common-sense actions. In March 2007 Lovins gave a series of five evening lectures at Stanford University and these are available for free download as podcasts through iTunes. I found these less than a week after my pump had been installed... and boy did I wish afterwards that those two events had occurred in the opposite order.

In the Tuesday night lecture on improving energy efficiency in industry, Lovins focused fairly heavily on pipes and pumps. Apparently a very large percentage of the electrical energy used by industry is consumed in the motors of pumps. The point is made that due to the compounding energy losses between electrical generation (usually in a coal-fired power station) and consumption in the motor, even a relatively small improvement in end-use efficiency will be multiplied back through the chain to deliver a far more significant drop in generating capacity requirements and associated pollution emissions etc.

In the pursuit of those end-use efficiency improvements, Lovins laid down a number of basic principles for designing energy-efficient pumping systems. I encourage you to watch the lectures for yourself, but my quick summary would have to include:

- If pipework looks neat, it's probably inefficient
- Short, fat, straight pipes are far more efficient than long, thin pipes with corners in them
- Engineers tend to optimise pipes and pumps separately focusing on up-front cost, when an overall cost reduction can be achieved by optimising them as a system for efficiency
- By optimising the efficiency of the system you can specify a much smaller pump which costs far less to buy, run and maintain
- It's usually best to design the pipework *first* and then lay out the equipment around them

That first point especially hit home. Have a look at the pictures in the previous post or two - I actually insisted that the installer do a "proper" job and fit two additional 90-degree bends in the pipe that takes water to the toilet instead of allowing it to curve smoothly (but untidily). I'm quite sure that if I'd watched this lecture beforehand I'd have spent some time carefully designing and specifying the pipes and pump which are going to be a fixture of our home for some years to come.

Oh well. On the bright side, check out the water use stats I'm about to publish in a separate post.

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