Maintaining the perfect temperature

Keeping offices at an acceptable temperature is an expensive business but a British engineer believes that windows filled with water could save companies a fortune by cutting their use of heating and air-conditioning systems.

‘The bulk of the cost is from air conditioning to cool offices in the summer,’ said Frederick McKee, an Essex based engineer and inventor of the new water filled window.

The system is based on double-glazed windows with water pumped between the gap in the two panes of glass instead of having an air cavity.

A chemical dissolved in the water absorbs infrared energy from sunlight but is transparent at visible wavelengths; so while heat is absorbed by the solution inside the windows, visible light passes straight through.

Water from the windows circulates through a heat exchanger, allowing the heat it contains to be stored for later use.

Alternatively, the water can be pumped to cooler, shaded parts of a building. In winter the solution absorbs heat from the office and radiates it back in.

‘The system basically enables us to put up a building that doesn’t need cooling in the summer or heating in the winter,’ said McKee. McKee estimates the normal annual bill for heating and cooling a 30-metre-square, 10-storey building at around £150,000. McKee is confident that with his new glazing system, the bill would be less than £3000 a year.