Energy Technologies: Pumps
Pumps have a number of quick payback energy saving options. With Emsol, you should be able to achieve savings of between 10% to 60%.Overview
Pumps often operate at less than 60% efficiency and so improvements should always be considered. For example, pumps are oversized to allow for infrequent high flow rates and, therefore, operate for 80% of the time at poor efficiency.
With pumps, the aim is to reduce the flow rate when low flow is sufficient, specify pump size so they operate at their Best Efficiency Point (BEP) and use Variable Speed Drives (VSDs) at times of low flow.
Many businesses underestimate the amount of energy wastage from using oversized pumps. Flow requirements and pressure requirements need to be specified with hours per year. This is so that a pump can be selected to operate at 85% efficiency for most of the time, instead of say 50% efficiency. Use a second pump for times of extra flow or pressure.
In most applications, the biggest cost of pumping is the energy they use and not the purchase cost of the pump.
A common and large energy saving option is to use VSD on one pump. This saves between 10% and 50% energy during part load operations instead of using a flow control valve. Another energy saving option if a pump is too large is to reduce the size of pump impeller. This is much less expensive than adding a VSD and will save a similar amount of energy.
Tips:
Some of the more effective tips for saving energy with pumps include:
- Find and stop water leaks within one week.
- Use a smaller impeller in a pump if the pump is too large.
- Ensure fluid flow is not excessive; reduce return flow in circulation systems.
- Remove pressure restrictions such as undersized filters.
- Reduce pressure if it is unnecessarily high.
- Ensure there is sufficient suction pressure to avoid cavitations at all times.
- Use VSD on one pump for low flow times.
- Use fixed speed pumps only for 80%-100% full flow.