Water Quality Sampling Kiosk
The Cairngorms provide some of the world’s highest-quality water, but maintaining continuous sampling in this region is difficult due to extreme winter temperatures, which often fall to –17°C and have historically reached –27°C. Sampling equipment and water supplies frequently freeze, causing gaps in essential water-quality monitoring. To solve this, Scottish Water, R2M and Morrison Construction developed an off-grid, winter-optimised sampling kiosk capable of operating reliably in these harsh conditions.
The kiosk was designed to maintain an internal water temperature of +2°C during external temperatures as low as –30°C, without any mains power. It also needed to be safe, maintainable, energy efficient, resistant to humidity and bacterial growth, and capable of remote monitoring and diagnostics. Every component was selected with winter resilience and circularity in mind, supported by a custom solar architecture that maximises energy capture during periods of minimal daylight.
Custom electrical enclosures were developed for the charge controllers and lithium-polymer energy cells, which include protection circuitry and internal heaters for charging below 5°C. These insulated enclosures preserve heat and allow remote monitoring of energy yield, consumption and alerts.
The water supply is protected by a 70W trace heater, supported by a compact carbon panel heater for extreme cold, both chosen for safety and low energy requirements. Internally, magnesium-oxide panels replaced traditional plywood or fibreglass, offering strong insulation, mould resistance and environmental benefits.
Ventilation was redesigned using insulated, passively closing vents and an active air intake with temperature-based logic: below 10°C the system retains heat, and above 10°C a low-power fan manages humidity. Initial solar positioning limited winter energy yield to 100–200Wh per day while heating demand averaged 250Wh. After reviewing performance, the kiosk was re-oriented to gain a south-facing panel, immediately increasing generation to over 300Wh per day even in partial shade. Temperature targets for the heaters were also refined to eliminate unnecessary energy use.
These optimisations enabled the kiosk to achieve a positive energy balance from early January, with fully charged reserves by late March and confidence to withstand the final cold spells of the season. Most importantly, Tomnavoulin experienced no interruptions to water-quality sampling for the first winter on record. The engineering principles proven in this project are now being integrated into new generations of self-powered equipment cabinets and sampling kiosks.
