Flowers inspire novel heaters

. They have no glazing but use a ring of petals to prevent heat loss to wind from the absorbing water tank at their base. The insides of the petals also function as reflectors to direct more light onto the absorber. The novel devices, called Solarblumes, also use a clever method of tilting to follow the sun as it moves across the sky. Water is pumped between two white balls to change the balance of the arrangement, which is supported by two curved metal tubes that allow it to rock. At each ball there is a photo sensor. If sunlight falls on it, a small pump starts up and pumps a certain quantity of water to the other ball, to tilt the arrangement until the photo sensor lies in the shade. A favourite application seems to be for warming water for swimming pools.