Solar Water Heater With Plastic Bottles





Introduction: Solar Water Heater With Plastic Bottles

How to make a water heater with big plastic (PET) bottles. Inside each bottle there is a 3.5 meteres piece of 4 mm drip watering tubing.
This heater takes advantage of the greenhouse effect inside the bottles. It is like the heat inside a car in the sun in summer.

Since when the circuit is stopped the water heats more inside the tubing it woul be a good idea to use a timer with i. e. 1 minute ON and 1 minute OFF. This also would protect the pump motor from excessive heating.

With a small water pump the water is cycled and the temperature rises.

It would be better to use a 12 volt DC motor water pump connected to several solar cells.

You can also try to paste a sheet of aluminum foil in order to concentrate more heat inside the bottles.

The solar water heater is scalable, so you can connect more bottles and groups of bottles in order to heat a swimming pool.

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    UV breaks down certain plastics, This is not a good idea for any water that would be consumed as it could contain BPA and/or other chemicals like pthalates leached out of the plastic.

    This is not intended for drinking but for swimming pools or showers, etc. By the way it depends on the material of the inner (black) tubing. If you use polyethilene there is no problem. Perhaps other plastics like PVC or others with BPA (Polycarbonate) could break down, but even in that case the UV radiation degrades the outer part of the tubing and not the inner part in contact with the water.