English: A solar heater taken from the design noted in "Earthship Volume 2:Systems and components" by Michael Reynolds. The solar heater should be initially positioned perpendicular to to spring or summer sun (equinox) if used as is or at a 90 degree angle from the mirror targeted at equinox sun. Water intake and outlet are to be equipped with valves. Can be set-up so it is totally gravity fed and requires no pumps, ... Can be easily build DIY at low cost. Only usable in areas with allot of sun (subtropics, ...). Originally designed for showering (but may accommodate other uses if hooked up to the houses' piping system).

For the elevation; the initial design by Michael Reynolds simply placed the water heater at an angle equal to "the line of the roof". However, the optimal angle differs for each location, and even during the coarse of the year (see http://www.macslab.com/optsolar.html ). Thus the solar collector is best placed on a adjustable (tiltable) platform. In addition, it is also best that the platform can be rotated to the sun, to "track" the sun during the day. Both are not essential for showering, ... since a person can simply change his lifestyle to shower at a moment when the collector has warmed up the most. For other purposes (connecting the system to ie the hot water system) a rotatable/tiltable platform is advised.

In regards to the hot/cold water inlet; this is correct, though noticable different from other solar collectors. This because I wanted the collector to also function with water that wasn't pressurised (ie cold water simply flowing into the collector via gravity, aswell as out via gravity). This can not be done if inlet/outlet are switched. If you were to change the hot/cold water inlet/outlet, then you could only shower for say 1 minute and then the hot water no longer flows out as it doesn't reach the upper outlet no more (water mass drops during showering). Thus, this setup is for this purpose the best one.

However, since hot water rises to the top, as is, this does give problems with circulating (pressurised) systems since the hot water outlet is placed entirely at the bottom. However for showering, this doesn't matter since you can simply wait until the entire tank has warmed up sufficiently (the "colder water at the bottom" thus still being warm enough for showering). I guess that a thermometer would need to be included for this though.

To resolve the hot water/cold water issue with the circulating (pressurised) systems, the hot water outlet and inlet needs to be simply swapped when using these collectors for this purpose.