Solar water heating: Part 1May 29th, 2011. Post by Quinta do Vale
That’s a shower! Bucket baths are all well and good and serve their purpose, but once in a while there’s nothing to beat the feeling from a shower.
After plumbing cold running water to the yurt, the next logical step was to think about hot water too. And thinking of hot water made no sense without thinking about a shower at the same time. It’s always been my intention to create a solar water heating system for summer use on the quinta, and to have a solar shower, but we never quite managed to get around to it last year despite having most of the raw ingredients sitting around the place waiting to be put together. So yesterday I finally got around to starting work on the first part of the system.
Here is the recipe:
It works like this. The cold water supply enters the radiator at the bottom. A tap regulates the flow so it can be adjusted to keep pace with the rate the water is heated. The heated water exits through the top of the radiator and, through a combination of convection and pressure (no pump is necessary), rises to fill a 200 litre tank on the terrace above. (For this to work, the solar collector must be below the storage tank.) The hot water in the tank can then be brought back down again to feed a shower and a hot water supply to the yurt.
There was enough sun this morning before the daily thunderstorms arrived to establish that this works. The radiator still needs a lot of flushing, judging by the colour of the hot water filling the tank, and its box needs a glass or perspex cover to magnify the heating effect of the sun and minimise the cooling effects of air, wind and rain. I’m going to make an insulated cover for the collector to minimise heat loss once the sun is no longer shining on it or to shut off the heater if temperatures get too high. The tank on the terrace above also needs an insulated housing to keep the water hot once it’s no longer being fed by the radiator, but so far this is looking promising.
I was wondering how the radiator would perform given that the input and output are on the same side of the panel, but increasing the flow of water and testing which parts cooled down first showed that the water does in fact circulate fairly effectively.
Main concerns at this stage are that I might need to replace the hosepipe and plastic tank with pipes and tank designed for much higher temperatures, but the radiator holds a large volume of water and by keeping it moving through at the right rate, it ought to be possible to prevent temperatures from getting too high.