Cheapest Solar Water Heater and Cooker needed which can keep the water warm for a few hours

I have read many of the instructables about hot water heaters. I am a person living with a really meagre salary so can not afford to find or buy things like refrigerator backs or car radiators. Even though, after having read all these instructables, I have a need as well as a wish to have some kind of water heater that can atleast warm the water in cold / rainy weather to a level which does not feel cold. Something ofthe body temperature level or warmer will do. AND after warming this water, it can be kept for a few hours without much loss in the temperature. Quantity could be like 10 liters or so. Any help most appreciated. The instructable using cold-drink bottles is a nice one but the quantity of water is very small so can't be used for bathing / washing etc. I'm also looking for a solar cooker with very low costs, which is able to cook rice in about 2 hours time. Any and all help greatly appreciated. Thanks, RS

Sandisk1duo8 years ago
just build this:

https://www.instructables.com/id/Build-your-own-flat-panel-solar-thermal-collector/

but spray paint that white screen thing black