News
Our “no-reagents” solar powered chlorinators are ready for field trials at off-grid Community Water Access sites
July, 2023
We are pleased to announce the successful completion of our Innovate UK SMART award project to develop a fully-automated PV-powered water chlorinator for off-grid water treatment without free-chlorine chemicals.
Our DCC chlorinators are solar PV powered. They treat water with no chemical additions, including salt, relying instead on ions naturally present in the source water. This approach combines onsite chlorine production and accurate chlorine dosing into one seamless and fully-automated process, with no dependence on consumable materials and minimal operating costs.
We have two complete field-ready units, with parts available for up to ten. Our Direct Contact Chlorinators (DCC) now reliably treat microbially contaminated water containing 13ppm (13mg/L) or more of chloride ions, to within a user-settable range of 1–5(±0.5)ppm; in line with WHO guidelines. The field-ready units pictured are based around our own proprietary power electronics to modulate electrolyser current with varying flow rates and chloride levels.
Leveraging an ongoing collaboration with Prof. Dan Rogers of Oxford University’s Power Electronics group, our chlorinators connect directly to any PV array with Open Circuit Voltage (OCV) in the range 30–100V, managing all power conditioning (Maximum Power Point Tracking and Voltage Regulation) internally. Users can input a target free chlorine concentration via two buttons with information fed back through a LCD. A simple calibration procedure enables non-chloride contributions to the mineral content of the water to be discounted without baseline water composition testing. The DCC also optionally enables automatic self-calibration via terminals that connect to standard Redox (ORP) and pH probes. A “normally closed” solenoid valve ensures that water is only delivered if it has been treated to within 0.5ppm of the target level.
In order to address water sources containing less than 13ppm free chlorine, or treat larger flow rates with a derived apparatus, we are introducing a salt dosing accessory that pre-seeds the water with common salt. Whilst this accessory does require salt to be brought to site, this is far cheaper than liquid hypochlorite and significantly easier to store. Refill intervals are also improved by an order of magnitude: liquid hypochlorite dosers typically treat 100s of cubic meters of water between refills, whereas we can treat 1000s of cubic meters. Using salt instead of hypochlorites or chloroisocyanuric acid tablets avoids the need for expensive and short shelf-life chlorine products and skilled operator-intervention, providing a user-experience equivalent to the occasional “topping-up” of salt in a dishwasher or water softener.
Thermofluidics’ chlorinators are set to transform water treatment, by dramatically lowering the complexity, operational and supply chain costs associated with delivering safe water and protecting users from post-source contamination. For more information, please read earlier news posts below or contact us.