News

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.

Professor Dan Rogers, key member of Oxford University’s Energy and Power group and Thermofluidics’ power-electronics guru, has handed over a prototype controller for our fully-automated PV-powered water chlorinator. The controller, built around a STM32 microcontroller, will integrate the key components that enable us to offer fully-automated water chlorination for communities without access to water or power-grids.

Chlorination is by far the most common water treatment method worldwide, and the only method providing residual protection against microbial contamination post-source. This is increasingly understood to be as significant as contamination at source, particularly when water is collected in buckets and carried to the home. However, its implementation is currently hindered by limited supply chains for chemical feedstocks, dependence on skilled operators, and routine maintenance requirements.

We will enable automated water treatment to internationally-recognised standards by PV-powered electrolysis, without depending on free-chlorine chemicals such as hypochlorites or chlorinated cyanuric-acids, skilled operators, or expensive and life-limiting components such as RedOx (ORP) and Ph probes. Using a novel approach, we are able to treat many groundwater sources that contain trace levels of natural chlorides without any feedstock materials at all, including common salt. This will result in a practical and cost effective solution to delivering water free from microbial contaminants at a community level off-grid.  Later in the project, we plan to integrate an accessory that will enable sources with insufficient natural chlorides to be automatically treated, without batch preparation or operator intervention, using widely-available crystalline salt.

The components of our chlorinator, already working well together with manual control, have since been integrated and controlled by a lab PC using National Instruments’ Labview. The move over to a purpose-built controller represents a major step in our drive to bring affordable water services to all.

We are delighted to announce that we have secured Innovate UK funding to turn our successful proof-of-concept solar PV-powered chlorinator into a robust and affordable commercial product.

Our novel approach to solar PV-powered chlorination turns dissolved chlorides, which are present in many groundwater sites around the world into free chlorine, treating water for bacteria and viruses and providing residual protection without depending on bought-in reagents or skilled-operator intervention. The way in which we do this also avoids dependence on expensive life limiting components to keep costs down. For water sources with extremely low or no pre-dissolved chlorides, such as river or pond water, we will introduce an accessory which produces free chlorine and treats the water as it’s drawn off, using crystalline salt as our only feedstock. Unlike existing solutions, our approach does not require batch preparation or routine calibration. 

The project, which began on 1^st January 2022, will keep our R&D team busy as our subsidiary Impact Pumps scales production of its SLX-40 submersible pump range, harnessing the Joukowski effect to bring reliable access to groundwater, particularly in off-grid areas.

Sophia Motteu, graduate chemical engineer and the latest addition to our growing team, has demonstrated a proof-of-concept electrolytic chlorinator in our Oxford lab. The chlorinator, which could enable water to be automatically treated to within WHO guidelines at the tap, could eliminate dependence on free-chlorine reagents and skilled operators on-site. It could be cheaply produced, and widely deployed at water collection points. Leveraging recent trends in power electronics and benefiting from cheap and widely available PV, the solution could cost-effectively treat viruses as well as bacteria, and provide residual protection against contamination beyond the point of collection.

We have completed Phase 1 of our Community Water project in collaboration with FundiFix Ltd. The project has successfully demonstrated that an Impact Pumps Solution can significantly reduce the downtime and lower the operational costs of providing a community water service, potentially by as much as 75%. These results were made possible by the relative ease with which maintenance issues could be identified and remedied, with almost all serviceable parts located at surface level. As intended, the solar surface pump used during the project was “swapped-out” for a petrol-powered backup on a few occasions due to extended-cloud and demand surges, and swapped for an equivalent solar pump after one instance of surface pump failure.

Construction work has begun at our two Community Water Access phase 1 pilot sites in Kitui County, Kenya, in collaboration with FundiFix Ltd. This comes off the back of 3 months of delays due to the Nairobi Coronavirus curfew, exacerbated by difficulty in managing this project remotely. Thermofluidics’ role in the project has so far involved providing equipment through our subsidiary Impact Pumps and pioneering a complete installation package and bespoke data acquisition and logging capability.

We have completed a full characterisation of a PS0 Impact Pump at our U.K. test facility, gathering multi-period time-series traces from piezo-electric microphones at several input data points for each parametric variable. The raw data, hot off the press, shows excellent SNR, including a number of features of known or suspected origin, as well as some unknown periodicity. Post processing over the coming weeks and months will reveal more about what real-world information these encode, with a view to introducing on-site data processing and cheap and robust remote-monitoring in the longer term.

Our first Impact Pump prototypes in Africa beyond Kenya are installed and lifting water from an open well and a drilled borehole for irrigation on a farm near Ndola, northern Zambia. These are PS0 (Pre-Series 0) prototypes, powered by a Futurepump SF2 and Ennos Sunlight pump, respectively. These units were installed by local plumbers with minimal instruction and will be used to conduct a number of farm-based studies as part of a wider project looking at the introduction of sustainable horticultural practices into the region.