Solar Hot Tub with Mini Constructed Wetlands

This is an ongoing experiment! We are working to develop a year-round hot-tub system that is heated exclusively by the sun. The water is filtered through a mini-constructed wetlands so that the same water may be used for days or weeks. Keeping the water in the tub also allows for the water to store some heat from one day to the next.

Our first solar collector was built by coiling 800 feet of 3/4" irrigation tubing on the inside surface of an 11ft diameter satellite dish. The water is circulated through the tubing with a small pond pump. This collector worked well in the summer months. As the air temps cooled and the days got shorter, we found that we lost too much heat from the "unglazed" collector and couldn't keep the tub warm enough. The satellite dish / tubing collector should be sufficient for more tropical climates. The tubing holds about 20gallons of water making it an ideal candidate for a solar shower heater.

We're now experimenting with commercially produced flat-plate collector solar heaters to heat the tub instead of the satellite dish / tubing collector. Look for updates on our progress!