Energy saving on circulation pumps

With the growing awareness of the need to improve energy efficiency of buildings, not just for cost savings but also for reduction of carbon footprint, asset owners and tenants are increasingly scrutinising the energy consumption of circulation pumps in their buildings.

This is with good reason. Pumping systems account for nearly 20% of the worlds electrical energy demand. A 7.5kw pump will consume 65,700kWh per annum running at full speed at all times, and 90% energy consumption is 90% of the total cost of owning a pump.

Many buildings have now retro-fitted variable speed drives to fixed speed pumps, which can reduce energy consumption if set up correctly. However, maximum energy efficiency is usually only available when using pumps with built in variable speed drives. This is because a pump with a built-in drive will either have built in pressure sensors or use known performance data of the pump to regulate the pump according to demand.

The demand for heating and chilled water in a building can vary hugely depending on occupancy levels and outdoor temperatures. By dynamically varying the speed of the pump according to the demand for heating or cooling in a building, we can adjust the pump speed automatically in real-time to ensure optimum efficiency. A 10% reduction in pump speed can result in a 34% saving in energy due to the affinity laws.

Our experience shows that it is possible to reduce energy consumption by 80% compared to a fixed speed pump. If you'd like further guidance or advice, please give us a call and we will be glad to help.