Tuesday, March 21, 2006

Negawatt* News

Save Negawatts* of energy ! Draught excluders by the yard or metre...
Experimenting on something else, we discovered a curious property of silicon mastic, the stuff you seal around bathtubs and sinks with - although it sticks like dung to a blanket for almost everything, it doesn't stick to masking tape.
Friends had a very draughty house, an old farm, and the door frames and doors were much too irregular to use the self-adhesive foam strips, or the nice everlasting phosphorus-bronze kind sold for the purpose of keeping out the gales.
We stuck masking tape, the pale-yellow paper kind used by careless painters, onto the edges and top of the door and either side of the frame recess, extruded a healthy bead of mastic onto the frame and closed the masked door onto it overnight.
In the morning the door opened easily enough, for the silicone had not stuck to the surface of the tape. We peeled off the tape and cleaned up a bit with a sharp blade and lo, a silicone seal that fitted perfectly into the humps and hollows in the door, which then closed with an ear-popping clunk as in a posh car. Curiously, brown mastic was cheaper than transparent, and you can use white if your doors are painted that colour.
This works for lumpy windows too, of course. I can't include images in list mails, so if you are interested, but aren't sure what to do I've made some explanatory images - write to me and I will forward them.


* Negawatt - large and otherwise expensive unit of energy that you don't use.

simeon@raindropkites.co.uk

Wednesday, March 08, 2006

Click to enlarge the image.

Liquid piston heat pump drive. Project - March 2006.

"Liquid Piston" air compressor with concentric double-acting pneumatic intensifier. The intensifier cylinder is 1m in diameter.
Designed to drive a heat pump for domestic heating and hot water supply, using the spent drive water as the source of low-grade heat. A water source with a head of 30m or more alternately fills and empties the two main compressor drums. As it is the surface of the water that acts as the seal there is no wear or leakage - the loose-fitting wood and foam "false pistons" shown prevent thermal exchange between the drive water and the air above, reduce splashing and actuate the change-over mechanism (not shown) at the end of each stroke. Two conical traps remove condensation from the compessed air. Unless a very large head of water is available, the pressure generated is insufficient to drive an efficient heat pump. Here a pneumatic intensifier increases the primary pressure to over 30bar, permitting the use of carbon dioxide as the high pressure refrigerant medium.
Designed to run continually, with a minimum of maintenance, the installation is intended for domestic or small community use. A cold store or small freezer can easily be adapted as part of the heat source.

Left Hand Thread...Where no man has boldly gone before...















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