Solar Hot Water on the Cheap
There’s a downside to nearly all renewable energy technologies available for homeowners. Cost. Though over time a solar power or small wind system may pay for itself in savings from not buying fuels or power from the grid, the initial outlay for renewable energy is staggering for mere mortals. Despite the wisdom of a penny saved is a penny earned, most Americans consider sales price first, long term savings last.
However simple, low tech, clever products or affordable high tech plug and play technologies may be the key to bringing renewable energy into the home. For example a water-filled black rubber, plastic or even canvas bag hung from a tree limb is a way for campers to grab a hot shower courtesy of the heat of the Sun. Like the hot water that flows from a garden hose lying on the ground on a sunny day, given a few hours a sack of water hanging in the sunlight will provide a soothing, though brief, shower. These solar water heaters are plentiful through camping and outdoor supply outlets. (The technology has advanced, too, with some models offering battery-powered pumps so the solar heated water can be used for more than showers.)
Now the Industrial Design Consultancy (IDC) of the UK has taken the black bag solar water heater concept and expanded it a bit more. Its design, the SolarStore, appears much like an inflatable mattress but it’s double chambered. The inflated outer chamber is clear and allows sunlight through to the black inner chamber which holds about 8 gallons (30 liters) of water. The inflated chamber helps SolarStore hold its shape air also insulates the water filled area. The weight of the filled bag holds it in place on any surface. Additionally a header tank - another water filled bag - connected by hose and positioned at a higher elevation than the SolarStore “mattress”Ě itself allows for constant water pressure.
Fully inflated SolarStore is has about two meters square or nearly 22 square feet, plenty of surface area to absorb solar radiation. IDC says up to three full tanks of water per day can be solar heated to temperatures close to 80C (176 F).
SolarStore is geared towards homes in developing countries as well as recreation users or at remote sites, like that safe cabin in the woods. Uninflated it can be carried in a knapsack. But its portability shouldn’t be a deterrent to more permanent installations. It seems feasible that crafty homeowners could use multiple units working in parallel to provide ample, very low cost hot water for homes. Hot water could be used for heating and/or domestic use. Even if the SolarStores have to be replaced every few years the energy savings might be worth it.
The appeal of course with any simple low tech design is the low initial outlay of cash. IDC estimates that SolarStore should sell initially for under GBP100 ( under $200) per unit. However, SolarStore looks like it’s the kind of product that if mass produced could sell for much less. The company says the cost of a SolarStore should be paid for in energy savings in 6 months at UK energy costs.
In a cautionary note, as with any new untested-over-time product the long term durability and functionality are unknown.
The company, with patents secured and manufacturing capabilities in place, is now seeking potential distributors worldwide.
Industrial Design Consultancy