Coutts finds another way to cut costs

Private bank Coutts & Co has cut by 90% the amount of energy it uses in its air conditioning systems, achieving a savings of £70,000pa.

The solution was a comparatively simple one - fit new variable speed pumps.

"The pumps are now running at about 40% of maximum speed," says facilities manager Mike Ingram, "whereas before they would be running at 100% continuously."

"In addition," he notes, "hot water is used more efficiently, saving gas. Before, we would pump water out at 40C and get it back at 40C. Now, the return water is 32C."

Simple recirculation is the least efficient way of running a pump, says drive specialist Alldales, since the system runs full-out regardless of need. Small decreases in pump speed can lead to large energy savings Ð decreasing centrifugal load gives a power decrease based on the cube of the load.

In Coutts' case, pipework sensors feed back to the pumps, regulating speed to ensure optimum use of the water's energy content.

Elliott Chase