Posted on 14th Feb 2023
Energy saving for fans and pumps with inverter drives is a great way to reduce energy costs. Darwin Motion drives allow for the speed of the fan or pump to be adjusted to match the demand, which can result in significant savings. For example, in industrial drying processes, the fan speed can be adjusted to match the air flow rate and density of material being dried. In agricultural pumps, the speed can be adjusted to suit the flow and pressure required for irrigation systems. Large greenhouse ventilation schemes and pumps are often speed controlled to suit the distribution of heated air and water to the various growing areas.
A single fan and ducting can provide ventilation or extract for a number of machines. By using motorised dampers in the ductwork and a Fan/Pump rated Variable Frequency Drive, the fan speed can be reduced when machines are not in use. This is an effective way to save energy and reduce costs.
Most VFD have multiple digital inputs which allow for pre-set speeds, making this application easier to manage. Additionally, a 50% energy saving is available for only a 20% reduction in speed for Fans and Centrifugal Pumps. This is because power consumed follows the cube of speed, so greater savings are available for greater speed reductions.
A few examples of energy savings with inverter drives include:
1) Reducing the speed of pumps used in water treatment plants;
2) Reducing the speed of fans used in air conditioning systems;
3) Reducing the speed of motors used in manufacturing processes;
4) Reducing the speed of blowers used in dust collection systems.
Commercial buildings that are not fully occupied can reduce ventilation fan speeds to suit the density of occupation, weather conditions, outside temperature and the time of day or night. This is an effective way to save energy and reduce costs. There are a number of specialist Contractors who provide this service and can help businesses save money on their energy bills.
For example, a contractor could install sensors in the building which measure the density of occupation and adjust the fan speed accordingly. Additionally, they could install a remote sensor to form a control loop which further reduces energy consumption.
Cooling Tower fans can be speed controlled by Darwin Motion Drives to maintain the cooling water temperature. This is a simple application for a suitable temperature controller with a 4-20mA modulating output. The inverter drive can then be used to adjust the fan speed accordingly, ensuring that the cooling water temperature is maintained at the desired level. This helps to reduce energy consumption and costs.
Pumps can be speed controlled by Darwin Motion VFD to suit a constant pressure, in place of a by-pass flowing for pressure relief. This is an effective way to save energy and reduce costs. A suitable pressure sensor can be used as feedback to the built-in control loop facility resident in most Inverter drive products. This allows the pump to adjust its speed according to the pressure, ensuring that it is maintained at the desired level.
