Energy Efficiency Reference/Pumps & Fans

Pumps & Fans

Articles

• "Ask an Energy Expert: Optimizing Your Industrial Fan Systems", Summer 2008, Energy Matters

Reference

• Pump Reliability and Maintenance Cost - attached below

Example ARs/EEMs

• none yet uploaded

Data Collection

Jest about every plant has pumps. Here are the basic things to look for and collect.

1. Pump nameplate information

 - Brand Name
 - Cat. No
 - HP
 - RPM
 - Voltage
 - Max Amperage
 - Line Frequency (either 50Hz or 60Hz
 - Max Flow rate

2. Motor Nameplate information (if it is not a direct drive pump)

 - Brand Name
 - Cat. No
 - HP
 - RPM
 - Voltage
 - Max Amperage
 - Line Frequency (either 50Hz or 60Hz)

3. Fluid being pumped

 - Its viscosity and density (or if they know it its specific gravity)

4. What kind of system the pump is used in 5. Any Abnormal conditions such as a high/low temperature feed to the pump 6. Flow Rate (and how often the pump operates at this flow rate) 7. Gauge Pressure on both sides of the pump (This is often hard to accomplish since very few pumps will have pressure ports on both sides of the pump.) 8. If there are no gauges here is some more information you will need:

• • Inside pipe diameters for the inlet and outlet of the pump
  • If the pump is fed by a tank or a well open to atmosphere, get an estimate height of the water level above or below the center of the pump.
  • If the pump is fed by another source:
    • Find a gauge somewhere along the line feeding the pump (if it is fed by a city water line you can get the pressure the water is delivered at from the utility company)
    • Measure (or estimate) the height of the gauge above or below the pump center
    • Identify and Count elbows, valves, tees, pipe diameter changes, or any other connections in the pipe (if this is not possible make your best estimate)
  • A gauge pressure somewhere along the line leaving the pump or an outlet pressure
    • Measure (or estimate) the height of the gauge above or below the pump center
    • Identify and Count elbows, vales, tees, pipe diameter changes, or any other connections in the pipe (if this is not possible make your best estimate)
  • An Amperage Reading
  • If you want to find out more about pump operation set HOBOs to monitor the amperage

Questions to ask plant personnel

• At what flow rates does the pump operate and for how long?
• How are different flow rates achieved (for example throttling the inlet, VSD, Bypass control, On/off control)?
• Does the pump only run when needed?
• For what purpose was the pump originally designed, and is this the purpose it is now being used for?

After the Audit

Now it is time to put all data together to start writing some ARs.

Pump Efficiency AR

1. Start by inputing your data into PSAT (start, programs, IAC applications, PSAT 2008, PSAT 2008)

 - The first thing to do is to determine what type of pump you have. PSAT has a drop down list of pumps to choose from or you can set a specific optimal efficiency.
 - Enter the RPM of the pump
 - Choose the type of drive (either direct or belt)
 - Leave the Units alone (they should be set to gpm, ft, hp)
 - Change the kinematic viscosity and specific gravity only if the fuild is not water (to calculate specific gravity from density get the density into g/cm^3 and divide by 1g/cm^3 (density of water))
 - Set the fixed specific speed to no unless you know the pump has a fixed specific speed
 - Input the motor information into the next box (if its a direct drive it is the same as the pump information)
 - Enter the operating fraction (the amount of time the pump operates at the load you are looking at)
 - Put the incremental cost in the next box
 - Put the flow rate you got in the field in the next box
 - Click on the head tool button and fill out the boxes based on what you observed in the field (you can select the type of system you have by either selecting a suction and discharge line system or a suction tank and discharge line system)
 - Switch the button that says power to current so you can enter your amperage reading.

2. Now that your data is in PSAT you know how efficient the pump is and whether or not you should write a pump efficiency AR

 - Most pumps will fall in the 60-85% efficiency range when operating properly.
 - Anthing above 65% is exceptionally good and you might want to write up a best practices section instead about how the company has properly scaled their pumps
 - Between 85% and 60% is questionable depending on the type of pump and its application (if your in doubt about what efficiency is normal for your pump talk to Joe)
 - Below 60% is not good except for low rpm pumps which may only have an efficiency of 25%-35% (talk to Joe if you are in this range). This is the range at which changing pumps becomes feasible.

3. here are some common recommendations for pump efficiency AR

 - Replace pump (only a good solution if your pump is really inefficient (really over sized) because pumps are really expensive and the payback time is very long)
 - Trim Impeller, Smaller impeller (good for over sized pumps that run most of the time at a certain flow rate)
 - Install a VSD (good for pumps with throttle controls or bypass valves that run at several different flow-rates)

Install Controls/Turn off Pump AR

1. Identify any time when the pump(s) may be running that they may not be needed. This might be a pump running continuously when it is only needed for certain parts of batch processes. It also might be a pump running all the time when it is only needed during certain operating hours. 2. Determine if the pump can just be turned off by plant personnel of if some control system needs to be installed.

• Plants where the pump can be turned off overnight or on weekends can be turned off by personnel
• Plants were the pump only needs to run for a fraction of each batch process would benefit from a control system being installed to turn off the pump.

3. Calculate the electricity being used by the pump when it is not needed to operate. From this and the incremental cost of electricity you can find the cost of operating the pump when it is not needed. This is you cost savings. 4. If this is a pump that can just be turned off by plant personnel you are done. There is no cost to just having plant personnel turn off the pump when it is not needed. 5. For pumps where some control system needs to be installed you need to calculate the cost of installing the control system.

• First you need an estimate of how much the contrl system for this plant will cost. You will also probably need soft starts on the pumps so that they can be stopped and started without straining the motors.
• Next you need to estimate how much time it will take an electrician to wire in the new control system and how mush they will charge.
• Now you can add up all the costs and complete the AR.