Energy Consumption of Heater and Pump

The pump is running at 80% of its maximum load. That's good news, for if it were over 100% then sooner or later the circuit protective device will operate and the pump will stop for a rest.

It shouldn't be any surprise that an electric heater is operating at 100% of its rated output!

Plant energy consumption can be reduced by looking at usage patterns. Is this what is wanted? _{<subscribes to thread>}

To explain the technical explaining to other non technical person, it is always very difficult task to accomplished but someone have to do it.

Base on my experience working in the heavy industrial for over 26 years in the maintenance line and still working and still learning, all equipments are design and calculated by the machine designer or the suppliers and I can conformed to said that, there is NO over design of these equipment. Over design equipment or the power will cause wastage to the designing company or the end user and no body will wanted to buy it, as the cost will be higher than the nominal design capacity.

Specific design motors that couple to the water pump are design according to the nominal motor power capacity to compensate the extra load inside the water line such as water pressure , pump impeller, friction, pipe bending, pipe reducer, valves and e..t.c… These calculated motor power is need to overcome these extra load inside the pipe line or otherwise, you may have problem in the delivery of the water requirement needed to your process plant.

Yes, you can said that, the pump motor is correct and it always run at 80 to 85 % of the total motor rated load. Why, am I so confident about this?. I have always checked and measure the actual motor running current against the actual motor rated current and for all the pumps, the actual running current is always at 80 to 85 % of the total rated running current.

Motor can never- never run at 100% at it rated current unless if your motor is under capacity. I have a experience with one of my other plant that, the other department design the water pump couple with the right motor capacity but wrong motor speed. What we have is that we need to run two motors in order to pump the water. Running 1 motor will cause the motor overload trip as the running current is 40% over the rated motor current. This is because of the extra load inside the water line such as water pressure , pump impeller, friction, pipe bending, pipe reducer, valves and e..t.c…

I have seen some air compressor unit run at 125% of it rated motor capacity, all the time. There are some companies that design these air compressors and use up all the Service Factor of the motor to run their compressor. This is to save cost in manufacturing stage. But running the motor at its full capacity for the end user is not good. These motor life will be shorten due to heat generated inside the motor winding and it is very bad for the motor. The motor winding will overheat and cause insulation breakdown and at the end of the day, your motor winding will burnt. It caused production downtime and losses.

For heaters, the running current is always at 100%. This is due to the resistance of the heaters. Heaters running at 90% is not efficiency as the temperature is not hot enough and you may not able to achieve the desire temperature.

Simon, thanks for sharing your experience. Please allow me for further inquiries. How can one optimize/reduce the energy usage for an electric heaters? Is there a chance? May I say that CONTROLLING parameters are the more important one?

Someone suggests that to control the heater energy usage according to load (instead a step control, I can have a continous control for the electrical heater)i.e. not on 100% load, rather it works at different stages, at 35%, 60%, 80%...is that a way? Thanks!

For the heater the most importance point is to control the heating parameters of the heater. A good heating parameters help to optimize the wastage of energy. Most of the heater, now days, are using a controller to control the heating of the heater of the process and most of these controller are come with a PID (Proportional Integral Derivative) controller. It is a very good controller where it can able to control and maintain the temperature of the heater.

Like other heaters controller that is without any PID controller, the heater may over heated before it cut off the supply and thus, the energy is wasted or when it detected your temperature is too low , it start to switch 'on' the heater. Energy also wasted as it need to reheat up again.

A good controller will able to help you to save cost.

Hi Simon,

Can you help me know if we can have insulating material below the heating element to reduce heat loss ???

Can you help me on how to calculate the heat loss in electric plate heaters?

Thanks

Purely resistive loads i.e. electric resistance heaters and incandescent light bulbs, will always draw 100 % of rated (or very, very close to) current. Pumps, obviously have motors, which is an inductive load and the variables that are inherent require a significant time investment to understand. I suggest you consider an Automatic Unity Correction device if you want to improve efficiency, installed by a business which specializes in same. To address your last question: STANDARD electric motors are not that efficient.

Dear spteng

Presumably you are trying to save some money and/ improve the performance of your installation. From the limited information supplied it would appear that your electrical heater is on for 100% of the time which suggests it is either uncontrolled or under sized for the application. The pump appears to be doing what it says on the label!

Perhaps you need to consider better temperature control arrangements possibly even a thermostat if there isn't one installed at present.

You are going in the right direction because until someone starts checking up on consumptions nothing of meaning really happens!

Keep up the good work.

Massey

Dear all, thank you for the information provided.

In fact, I have a plant with increasing use of energy. The exisitng energy consumed for the plant is 50% much higher than the proposed kWh/ton of material feed. In optimizing a process plant energy usage, is CONTROL the main issue? Thanks