Solar Thermal

Solar Thermal evacuated tube collectors Two x 170 Litre , " Batch Collector" solar thermal water heaters at the Permaculture Research Institute of Australia. The 20 x 17 litre vertical , stainless steel boilers are sheathed with evacuated cylinders, internally coated with a selective surface so as to become infra-red antennae  .  Because the cylinders are mounted vertically they absorb solar radiation from all directions , direct and diffuse so Summer performance is absolutely incredible and far far superior to standard flat plate units. The hot water cascades from the top of the solar thermal boiler tube to the bottom of the next boiler tube for extremely fast heat pick up and recovery, similar to the multi tubed fire box / boiler assembly of a thoroughbred express steam locomotive.  Also, the fact that they are vertically mounted enables them to be installed on the walls of multi-storey and high rise buildings, where solar water heaters cannot ordinarily be employed.
      Above Left In this case a 130 Litre Batch Collector , hybrid solar water heater is mounted on a roof but the big advantage with this type of unit is that it may be installed at ground level . They are particularly effective when positioned in line with or adjacent to tank water supplies. They are extremely simple to install and many units may be coupled together for Industrial or factory hot water supplies.
Above Right 180 Litre Batch Collector type solar water heater prior to installation of the vacuum tube insulator sleeves . The tanks are of stainless steel and are manifolded together in the base of the unit.   The input and output ports can be seen at the bottom left hand side. Some polystyrene foam packaging is still attached.