Energy Conservation and the Electronically Communicated Fan. Theory Benefits Application A Typical Installation

Transcription

1 7 th Annual Energy Conservation and the Electronically Communicated Fan Theory Benefits Application A Typical Installation Presented by: Adam Perry, Platte River Power Authority Ed Hegwood, Rocky Mountain Education Center

2 Why are the Following Utilities doing Prescriptive Rebates for Electronically Communicated Motor Driven Fans

3 Electronically Commutated Motor Rebate Retrofit your constant volume HVAC fan boxes with Electronically Commutated Motors (ECMs) and Puget Sound Energy will provide you with a rebate of $0.12 for every square foot served by the HVAC fan.

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5 Electrically Commutated Motors (ECM) $350/kW

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7 All of these fans have the potential to be retrofitted to EC Fans

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9 Theory

10 How It Works The EC fan has a DC (direct current) motor operating off of an AC (alternating current source). The EC (electronically commutated) brushless motor has permanent magnets in the rotor, which revolves around the outside of the motor.

11 How It Works The EC motor behaves like a brushed DC motor as the speed under load is proportional to the drive voltage and the developed torque is in linear proportion to the current. The EC motor has a sensing and feedback circuit to ensure that the correct speed is obtained.

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13 Benefits

14 Airflow Efficiency This metric characterizes overall airflow efficiency in terms of the total fan power required per unit of airflow. Total Fan Power (W) / Total Fan Airflow Cubic Feet per Minute (CFM) 1.25W/CFM (Standard) Exiting CRAC/CRAH Units 0.75 W/cfm (Good) 0.5 W/cfm (Better) with EC Fans

15 Retrofit for Efficiency Improvements for Legacy Data Centers and other Commercial Buildings What s in it for You? kw Reduction

16 Application

17 Forward-curved blades use blades that curve in the direction of the fan wheel's rotation. Efficiency is less than backward curved bladed impellers.

18 The backward curvature mimics that of an airfoil cross section and provides good operating efficiency with relatively economical construction techniques. Backward-curved fans are much more energy efficient than forward curved fans.

19 Replacing the existing forward curved fans with EC (electronically commutated), brushless motors and backward curved fans. Value added savings are the removal of belts. Traditional fans are belt-driven which can absorb 5 to 15 per cent energy even when they are correctly installed, plus the cost of replacement and regular servicing. No belts also means no belt dust, thus removing a major concern in maintaining the clean environment of datacenters.

20 A further advantage of using these alternative fans, is the vastly improved airflow across the cooling coil. Most CRAC/AH unit existing fans are positioned just under the cooling coil, which causes three unnecessary issues: 1. FC fans block part of the coil, reducing the surface area and its efficiency. 2. The airflow has to split on either side of the FC fan, and then turn 90 before it can be distributed.

21 3. Air for FC fans is distributed into the floor slab, causing turbulence and resistance, which uses up energy, EC fans can be located much lower down in the floor, thus removing the dead spots over the coil s surface and reducing turbulence and resistance.

22 Forward Curved Fan EC Fan Reduced AIR FLOW AREAS Recirculation Zones 17

23 EC Fan Energy $ avings Calculator EE Level 3 ABC DC -23 Data ea. Data Center Aire DA CRAC Customer Yellow = Inputs Enter your total electricity cost ($/kwh) $0.075 Total Amps CFM For EC Fans ,000 Enter the number of EC Fans needed (6,000 CFM Fan Utilization Factor 71.94% Voltage Voltage Enter Cost per EC Fan to Retrofit Unit $2,732 $160,000 Rated Fan Amps 19.6 Rated 480 Enter Motor Voltage 480 EC Fan CFM De-Rated Fan Amps Actual 480 Enter % of Flow 60% 241,200 $140,000 Actual Amps 14.1 Derate = 0.00% Enter Number of CRAC/CRAH Units to be Retrofitted 23 Total Amps Corrected CFM 326,149 $120,000 Existing Unit Total Fan Motor Current Amp Draw/ phase CFM Correction Enter Existing Unit Total Fan Motor POWER FACTOR 0.85 CFM $100,000 Enter Existing Unit Total OEM Rated CFM 11,700 Job Site CFM Alt Ft Correction Existing Unit Fan Motor Utilization FACTOR 71.94% 234, $80,000 YOUR ESTIMATED ENERGY SAVINGS & PAYBACK kwh kw Annual Energy Spend Belt Drive FC Fan $150,390 2,005, $60,000 Annual Energy Spend EC FAN $27, , TOTAL ANNUAL SAVINGS $123,031 1,640, $40,000 TOTAL EC FAN UPGRADE COST $183, TAXES EC FAN Maintenance COST Avoidance $4, $200/Unit $20,000 ROI/ PAYBACK in Years 1.45 kw Saved $???./kw $74, $0 ROI/ PAYBACK with Rebates in Years 0.84 $400 < Rebates Annual Energy Spend Annual Energy Spend Fan Motor Heat Gain Reduction ( Increased Cooling to Floor) 622,167 BTUs-Cooling Belt Drive FC Fan EC FAN Total Capacity Made Available and returned to your Environment Amps/phase Existing Retrofit Water Savings at Power Plant 623,356 Gallons / Year Fan W/kBTUs Fan W/kBTUs Carbon Dioxide Equivalent Avoided 2,460,615 Pounds / Year Assumptions: 8760 Hour/Year Operation, 72 o F 35% RH. Energy Savings based on average EC fan modulation and amp draw as identified Disclaimer: Calculations are based on estimates and the assumptions shown above. While every precaution has been taken to ensure accuracy and completeness, We assume no responsibility and disclaim all liability for damages resulting from use of this information or for any errors or omissions. ENERGY COST COMPARISON W/CFM W/CFM

24 EC FAN Savings Points - EMERSON Energy Efficient EC fan savings up to 36% Variable Fan Speed Direct Air Path Lower Energy Consumption Blower System A Blower System B Blower System C CFM 8.6kW CFM 6.9kW CFM 5.5kW

25 Efficiency The efficiency of the EC motor (typically > 90%) is higher than that of traditional asynchronous AC motors (typically < 80%) and generates less heat, as there are no slip losses, less copper and iron losses. The EC motor is also more efficient than alternative speed control methods including: Inverter, AC frequency control, Triac voltage control, Multi-taped transformer voltage control (steps), and Star/Delta switch (two step)0

26 The DC motor is inherently more efficient than AC motors and, therefore, operates at a lower temperature putting less thermal stress on windings and bearings, while also reducing the amount of heat introduced into the air stream (lessening the impact on total vs. net capacity of the CRAC unit).

27 A Typical Installation

28 EC fan Install completed in live DATA CENTER

29 67 FORWARD CURVED FANS AND MOTORS TO BE REPLACED WITH EC MOTORS AND BACKWARD-CURVED FANS

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31 Staging Area

32 Tech removing old motors and wiring

33 Tech removing old motors and wiring

34 Note: drop cloth on floor and organized tools

35 New EC fans ready for install Old fans were palletized for easy moving out of center

36 Three EC fans in place 30 Ton Unit

37 20 Ton unit, two fans installed 67 Fan Project Completed in Three Weeks

38 Pre-Project Measurements Avg. KW CRAC Measured KW 10 day average at a constant air volume CRAC Unit Number

39 Post-Project Measurements Avg. KW CRAC Measured KW10 day average at a constant air volume CRAC Unit Number

40 KW Measurement Comparison CRAC KW Measurement Comparison KW Measurement Pre Post

41 Actual KW Differences Unit# PRE POST Reduction-kW This was a sampling of the overall project, a total 67 Motors and fans were replaced. 110 kw total with more kw if fans are tied to server though put ***.

42 Fan Law (Cube Law): The motor power varies with the cube of the motor speed. *** Reduced Motor kw = Existing Motor kw x (speed2/speed1)3 10% Reduction 20% Reduction

43 Advantages of the EC Fan Imbedded Sensors in the Servers The ultimate goal of this project and a similar one conducted last year by Lawrence Berkeley National Labs*** is to link IT equipment directly to power and cooling systems, so that supply can be adjusted automatically to match demand.

44 ***The project has been a success, The main goal we had was to show that you could do this, that you could use the sensors in the IT equipment to control the building systems, and we achieved that," - Bill Tschudi, a program manager at Lawrence Berkeley. The amount of energy saved will vary depending on how efficient a data center is to begin with, he said. He predicted that most data centers would see a return on their investment within a year.

45 Bigger Air Handling Units

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50 A rule of thumb is that for each degree you can reduce your condenser temperature, you will save about 1.5% on your cooling energy costs.

51 Applications such as rooftop refrigeration condensers and heat exchangers can benefit from a dramatic noise reduction without sacrificing performance This diffuser is designed to recover this wasted energy by purposely and efficiently decelerating the flow and reducing swirl, boosting the pressure rise of the impeller. Aerodynamic efficiency is increased and acoustic noise is reduced.

52 7 th Annual Questions or Comments?

53 7 th Annual Thank you for Attending our Presentation