Variable speed drives

Installing variable speed drives enabled our customer to achieve even bigger savings than anticipated.

A large insurance sector customer (who prefers to remain anonymous owing to company policy) asked us to carry out energy and water audits at their main office and contact centre to identify potential efficiency projects. Our report showed that significant energy savings could be made by installing variable speed drives (VSDs) on 26 of their water pumps and air handling units.

What are VSDs?

Quite often, the motors installed to drive pumps and fans that move water and air are sized to accommodate peak demand, running at high fixed speeds. But this is not always necessary. VSDs can be used, for example, to adjust the speed of motors that drive water pumps and air handling unit fans, to meet actual demand for water and air flow accordingly. By not running at a high speed all the time significant energy savings can be achieved.

Our customer agreed to enter into a ‘first out performance contract’ with us whereby we funded the purchase and installation of 26 VSD units at one of their large office locations.

To recover the costs associated with the installation, we arranged to send monthly invoices based on the level of savings achieved, which would continue until the full investment was recovered. In effect, their energy bill would remain the same as prior to the installation, then reduce following completion of the payback period.

Initial estimates indicated that energy savings of 44% could be achieved, with the capital that we invested being repaid in 21 months.

Overwhelming success

Following the installation of the VSDs a huge 52% energy saving was achieved. This means that the capital cost funded by us will be recovered in just 17 months, enabling the customer to benefit from the savings much sooner, which in total equate to c. £92,000 per year.

To see how we can save you money on water and energy call us on 03457 704158.
A joint venture between Anglian Water Business and NWG business