Wednesday, 10 August 2011

And would you like some ramen and udon with your spaghetti?

So on top of the electric wiring, there are also water pipes and air ducts going around the house. Wire is relatively straightforward as electrons are pretty tiny and don't mind going around corners. Fluids tend to dislike corners as it disturbs their flow. They also take up a lot more room. In both cases there is a loss per unit length. This is most critical with hot water pipes with no insulation, running at 100 watts per metre. It may be least critical with return ventilation pipes, which will only lose or gain heat within the thermal envelope. On a small scale losses in wires are not a big deal, but in the bigger scheme of things, less than 40% of electricity produced by power stations reaches consumers, so well over half is wasted heating up wires.

The plumbers were in again the other day to move a drainage pipe that they had put in. Somebody had forgotten to mention that there is going to be a laundry shoot coming down from the bathroom to the utility room where the washing machine is. I suppose this is another kind of conduit, further confusing the electricity, water and air.

Presumably this is business as usual in the building trade, going back at least to "Twas on a Monday morning" by Flanders and Swann in the 1960s, and probably well beyond. Probably back to the first time humans tried to knock through from one cave to another, or had an extension built on to their mud hut. Getting crap around the house, and I mean the word mainly in the engineering sense rather than the vulgar sense, is probably not given enough consideration. 

The loft is one place where these conduits come to the fore. In most places, of course, we don't want to see wires, ducts or pipes, and I go along with whoever it is who described the external piping of the Pompidou-centre as wearing a colostomy bag outside your clothes. In the case of the loft, pipes and wires all need to be visible, as that is the room's job. 

The ventilation system is in the loft, so fresh air must come in from the outside, then be sent all around the house in supply pipes, then come back in the return pipes to be sent outside as exhaust. Electricity is also vying for this space, as the sixteen wires from the eight solar circuits, each of six panels, come in through the top of the wall into this room. They must go through two distribution boards, then through two power conditioners, preferable as soon as possible as the loss is higher on the DC than when converted to AC, although this difference may be marginal. The priority for the electrical wiring is to be as short as possible. The power conditioners must be placed next to each other, not one on top of the other, as they put out a certain amount of heat. Each corner in the air ducts increases the resistance and makes more work for the fans insides. And of course, extra length also costs more in piping, wiring or ducting.