Turning Sunlight into Freshwater
At the core of HelioVap is a proprietary solar evaporation platform designed to convert sunlight into localized heat for efficient water evaporation.
Rather than heating the entire body of water, our approach concentrates solar energy at the water and air interface, where evaporation occurs.
A boron carbide platform
A boron carbide (B₄C) based porous material forms the core of HelioVap's current solar evaporation platform.
- 01Capture Sunlight
- 02Localize Heat
- 03Supply Water
- 04Manage Salt
- 05Recover Freshwater
Capture Sunlight
Broad spectrum solar absorption
A porous, light absorbing composite takes in energy across the solar spectrum rather than a narrow band. It also holds up in saline conditions, where many absorbers degrade.
Localize Heat
Heat where evaporation happens
Energy is concentrated in a thin thermal layer, inside which a phase change occurs. The porous structure directs source water back to that layer as it evaporates.
Recover Freshwater
From vapor to usable freshwater
Vapour meets a cooler transparent surface and condenses. The condensate is channelled away from the source water. Closing the gap between what evaporates and what is collected is the current engineering priority.
What the material has to do
Four requirements, at the same time.
No single one of these is difficult on its own. The engineering is in satisfying all four in one structure, because improving any of them tends to cost you another.
- 01
Absorb broadly
Sunlight arrives across a wide spectrum. An absorber tuned to a narrow band discards most of it, so the composite has to take in energy from the ultraviolet through the near infrared rather than at a preferred wavelength.
- 02
Hold the heat at the surface
Energy that spreads into the bulk warms a mass of water that is not evaporating. The structure has to keep the thermal gradient inside a thin layer at the interface and insulate it from the water underneath.
- 03
Keep the surface fed
Evaporation stops the moment the surface dries out. Porosity has to wick water upward at least as fast as it leaves, without becoming a thermal path that carries the heat back down into the bulk.
- 04
Survive the salt
Every litre that evaporates leaves its dissolved solids behind. The surface has to either reject salt back into the source water or tolerate what crystallises on it, over months rather than over an afternoon.
How the figure was measured
What a single number does and does not tell you.
The 2.8 kg·m⁻²·h⁻¹ figure is a mass loss measurement. A sample is illuminated under a solar simulator at one sun, and the water it loses over time is weighed. It describes the material, under laboratory conditions, at the evaporating surface.
It is not a system output. It says nothing about how much of that vapour reaches a condensing surface, how much runs back into the source water, or what a module would produce on an overcast afternoon in winter.
We publish it because it is the number we have measured, and we describe it as what it is. Where the published literature reports rates above the planar theoretical ceiling, the science page sets out the mechanisms that account for it.
under simulated 1-sun illumination
Laboratory evaporation performance. System-level freshwater recovery depends on system design, operating conditions, condensation and water recovery efficiency.
The measured figure is 2.8 kg·m⁻²·h⁻¹ at the evaporating surface. The daily figure is that rate over ten hours of illumination, not a measurement of a full day.
Not solved
The problems in front of us.
Collection efficiency
The gap between what evaporates and what is collected is the largest single loss in the system. Closing it is the current engineering priority, and no delivered water figure means anything until it is closed.
Salt behaviour over long durations
A short test tells you very little about what a surface looks like after a season. Extended saline exposure is the test that matters, and it is the one that takes longest to run.
Outdoors against the laboratory
Wind, humidity and ambient temperature change outdoor performance substantially, in both directions. A controlled indoor figure is a starting point, not a forecast.