The following products comprise a complete solar thermal system and are in various stages of beta testing.
The system is modular, running on a RS485 (industrial) network. Devices are typically powered from the network cabling. The software design is our own, as are the custom printed circuit boards. Initial versions use as many pre-built sub-modules mounted to these as possible to keep fabrication costs down.
Master control unit.
The master unit continually reads data from the roof-top (remote) temperature units, pump units and tank digital tank sensor unit. Based on this data, the system will constantly vary the pump speeds to chase the best efficiency it can for each collector bank. If your collector banks are oriented differently, different pumps will run at different flow rates as the sun strikes the banks differently. If your system requires different temperature water in different tanks, different banks can produce that. As the tank temperature approaches that of the bank’s output, the flow will decrease to always try to obtain at least the permitted temperature delta from the bank. Eventually it will stop and hold, and then, if the sun has been absent for a while, will allow complete drain-back.
The OEM pumps we use allow us to vary their speed dynamically and they transmit the fluid flow rate back in real-time. Pump data is read and written by our proprietary pump module/s. They connect to the master unit over the RS485 network. The master unit thereby intelligently controls the pump/s.
We have solved various fluid to gas transition problems and can run our system in a semi-syphon mode, thereby reducing pump power requirements.
In snowy weather, our system can detect collectors snowed up overnight and pre-heat them to shed the snow, thereby gaining many morning hours of solar collection that other systems (like solar vacuum tube designs) often struggle to because of their shape and inability to self heat.
We use custom made ‘all-copper’ flat plate collectors. The manifolds, risers and fins are copper. This is to eliminate possible galvanic corrosion occurring between aluminum fins which are often welded to copper pipes in other collectors. This all copper design gives better thermal efficiency and has a long life. We recommend collector banks to be no more than four collectors wide because of thermal expansion. Banks can be stacked, one above the other on the roof. In all cases, it is essential to ensure that complete drainage of all collectors occurs; so the banks should be mounted at a slight angle, and all pipework must drain back to the tank.
Remote temperature sensor.
Each bank of solar collectors needs temperature monitoring. We do this with our custom sensor module which reads data from a platinum sensor mounted in a small well in the final collector of the bank. The module can also detect daylight and ambient temperature. These roof top modules are typically the last nodes in the RS485 network so they run through a lightning suppressor. In this way roof top data is safely transmitted to our master control unit.
We intend to use non-pressurised polypropylene lined tanks, with a copper heat exchanger coil for DHW pre-heating, and another for space heating.
This description is subject to change. E. & O. E.