Reducing motor energy makes perfect sense
Did you know, that according to the World Energy Council, electric driven motor systems account for 50% of all electricity being consumed in the world!
Electric motors are running some of your buildings most critical equipment and should not be ignored.
By taking simple action, building owners can locate these power-hungry motors, save energy and cut down on system operating costs.
Are you looking at me?
An electric motor converts electrical energy into rotating mechanical energy. This is how water pumps and fans are driven to service high-rise buildings.
Electric motors are often hidden away within the machinery itself, which is why they tend to be ignored and left running even when they may not be serving the system they were designed for. It is due to this lack of attention that energy gets wasted, resulting in unnecessary utility payments.
Running 24/7 isn’t the only reason you’re burning energy
Electric motors have an optimal efficiency running point. When motors are over-sized they will run in part-load conditions. It is more efficient to run a smaller, properly specified motor near full load then it would be to run a motor that is too big for the duty it’s designed for in part-load.
Simply put, an oversized motor will consume power that isn’t being converted into the transmission of useful power. This extra power being used is called “reactive current” and there will be a charge for it on your electric bill.
Take a close look at the electric bill, you will see two key measurements – kW and kVA. Kilowatts (kW) measure the amount of power producing – “real work”. Kilovolt-amperes (kVA) measures the sum of real power and the added reactive current.
How to tame these wild horses – enter the Variable Frequency Drive
As stated, electric motors can be over-sized and will run continuously burning needless energy. It is because an electric motor has a fixed frequency and a fixed voltage. They are specifically designed to run at certain motor speed and torque. With the addition of a Variable Frequency Drive (VFD), a motor’s frequency and voltage can be changed, meaning the motor speed and torque can be varied. For example, savings of up to 50% are achievable by reducing the pump or fan speed by 20% – WOW! In addition to regulating motor speed and torque, a VFD will also offer system computing intelligence for further system control.
Some key benefits of adding a VFD to an electric motor would include:
- A significant reduction in energy consumption and cost.
- Smoother stop/start sequence, reducing wear on motor.
- Reduced frequency on parallel work loads between two or more pieces of equipment.
- Eliminating the need for control valves.
- System longevity with lowered overall maintenance.
5 easy steps for taking action:
Step 1: Compile an inventory of your motor systems in your building.
- Look at each system and identify where motors are situated.
- Record them on a motor/drive inventory.
- Generally, the larger the motor the more critical it is to building operations.
Step 2: Prioritize motors for investigation.
- Highest priority should be given to the biggest energy users.
- Multiply motor size by annual running hours.
- A smaller motor running more hours can use more energy than a bigger motor running less hours.
Step 3: Look for opportunities to optimize motor efficiency.
- Examine the whole motor system and all the components running.
- See if there are any further ways to improve efficiency.
Step 4: Look for opportunities to control the motor system.
- See if there are opportunities to switch off motors (make sure to follow manufactures stop/start guidelines as misuse can cause damage to motors)
- Think of control methodology and whether a fan or pump system would benefit from having a variable speed control.
Step 5: Seek a specialist help to make the necessary changes and measure the savings.
- Measure current motor system performance against building demand.
- Figure out what annual energy savings would be by adding in a control system and/or downsizing a motor.
- Monitor and measure the savings after changes have been made.
Investing in the future
To instate a control system for electric motors does require some capital investment. However, this is typically paid back in operational savings within a short period of time. Further, it may be worth investigating government incentive programs. Incentives offered for energy retrofits can make paybacks even quicker.
It is well worth the time invested to investigate the electric motors in your building for the benefit of system operating performance, energy savings and reduction in electricity costs.
For further information, don’t hesitate to reach out to our friendly team at Rikos Energy. All our details can be found on our company contact page.