Drainback Solar System
The system operates on an industrial RS485 network with modular components powered through the cabling.
- No collector to tank heat exchanger
- No glycol, 15% higher efficiency
- No freeze problems
- Almost maintenance free
Our products are local-control-only devices. Self-running; no internet connection required. Configurable with any device that can connect via a serial terminal. No application. No operating system. No cloud. No subscription.
Master control unit
The master unit manages up to four separate collector arrays, variable speed pumps, and accumulation tanks (typically 1,000+ litres each). It reads remote temperature data and continuously adjusts pump speeds for optimal efficiency based on collector orientation and sun exposure.
Pumps
Custom OEM pumps transmit real-time flow rate data via RS485 network modules. The system operates in semi-syphon mode to reduce pump energy consumption, achieving approximately 70:1 coefficient of performance.
Collectors
All-copper flat plate collectors eliminate galvanic corrosion risks between dissimilar metals. Copper's thermal conductivity of 401 W/mK is roughly 25 times that of stainless steel, maximising heat transfer to the working fluid.
We recommend a maximum of four collectors per bank width. Snow detection capability allows pre-heating to shed morning snow accumulation.
Temperature sensing
NTC thermistors in Wheatstone bridge configurations provide high-resolution temperature measurement across the system. An ADS1115 16-bit ADC with analogue multiplexing reads up to eight channels per node. Cascaded median and moving average filtering delivers stable, accurate readings.
This replaces the Dallas DS18B20 digital sensors used in earlier prototypes, which suffered from widespread counterfeit parts on the market.
Tanks
Non-pressurised thermal storage tanks (typically 1,000+ litres capacity) store heated water. Measured evaporation is approximately 100cc daily from 1,000-litre test systems using plain water.
Logging
A Windows/Linux daemon (runs on Raspberry Pi) collects RS485 network data, exports to CSV files, and uploads via FTP. A JavaScript HTML interface displays performance graphs.
View live data from our test rig
Connectivity
Single array modules require approximately 0.5W at 12VDC; pumps consume up to 70W at full flow. Internet connection is optional for logging uploads only. The system is designed for autonomous operation without internet dependency for security and reliability.
Errors and omissions excepted. No reliance can be made upon the accuracy of the information contained herein. Devices are prototypes only and are not for commercial sale. No liability can be accepted for any loss or damage arising from the use of any device or information provided.