re: rainwater shower experiments
7 jul 2002
>the "traditional" british water system is low pressure, of a mains supply
>pipe that supplies the kitchen drinking tap and the 80 to 100 gallon cold
>water storage tank in the attic...
about 3.5 psi for an 8' head, vs 40 or so in the us, equivalent to a 92'
head. lifting say, 200 gallons of water per day 92' for a month at 50%
efficiency takes about 200x8x92x30/0.5 = 8.8 million foot-pounds, or
3.3 kwh... 33 cents... no big deal.
>the advantage is that the cold water storage tank gives a constant head of
>pressure - not brilliant but constant...
given a large gozinta and small gozouta, vs vice-versa.
>a 1" pipe from the cold tank feeds a hot water storage cylinder, heated by a
>hot water heating coil, usually heated by a remote gas boiler or electric
>immersion heater. the hot supply of the shower has its own tapping from the
>hot water cylinder and the cold supply its own dedicated supply from the
>cold water storage tank. so, no interference from any other outlet.
and constant hot and cold water pressures for constant temp showers...
>lately torbeck valves are being fitted on toilet cisterns because they are
>quieter and are fully open until the cistern is full, which is not the case
>with the old ballcock and valve.
i wonder where to find a torbeck valve, or the us equivalent. rainwater
toilet flushing could be easy with a 6' head and higher flow fill valve,
vs a pump and pressure tank.
>the bath can be filled with easily 20 litres/min and the shower
>can have the same...
wow... a 5.2 gpm shower.
>the problem is usually the low head of the cold tank giving a poor shower
rich komp says this is mainly a problem for people used to hotel showers.
>having a larger shower head giving lower pressure high volume can solve it.
>raising the tank to the apex of the roof helps too. a 3 floor house with
>no bathroom on the 3rd floors give good performance.
many us houses have shallow roofs, not to mention cathedral ceilings
and owners with qualms about overhead water tanks.
>a pressure boosting method is put in a power shower pump on the shower only.
mix the hot and cold water first, then increase the pressure?
>another better method is to have a "venturi" shower mixer valve. this has
>the cold supply from the high pressure mains pipe and the hot from the
>low pressure hot supply...
the mains pipe being the one that supplies the tank. clever...