Workshop B Energy Efficiency Best Practices Use of Smart Data - - PDF document

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Workshop B Energy Efficiency Best Practices Use of Smart Data - - PDF document

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Workshop B Energy Efficiency Best Practices Use of Smart Data Analytics for Commercial Building & Manufacturing Cooling Plants to Identify Opportunities Tuesday, February 18, 2020 10:45 a.m. to Noon Biographical Information J. Kelly

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Workshop B

Energy Efficiency Best Practices … Use of Smart Data Analytics for Commercial Building & Manufacturing Cooling Plants to Identify Opportunities

Tuesday, February 18, 2020 10:45 a.m. to Noon

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Biographical Information

  • J. Kelly Kissock, Ph.D., P.E. Professor and Chair
  • Dept. of Mechanical and Aerospace Engineering /

Renewable and Clean Energy University of Dayton Kettering Laboratories 361-B, 300 College Park Dayton, OH 45469-0238 937-229-2835 Fax: 937-229-4766 kkissock@udayton.edu

  • Dr. Kissock is a Professor and Chair of the Mechanical and Aerospace

Engineering and Director of the Renewable and Clean Energy program at the University of Dayton. He is also Director of the University of Dayton Industrial Assessment Center. He is a Registered Professional Engineer in the State of Ohio. Dr. Kissock works in the fields of building, industrial and renewable energy systems. He has published

  • ver 100 technical papers on energy efficiency and renewable energy

and conducted seminars on energy efficiency across the world. Dr. Kissock served as Associate Editor of the ASME Journal of Solar Energy Engineering and has chaired several technical committees and

  • conferences. His work has been recognized with two Distinguished

Educator Awards by Who’s Who Among America’s Teachers, the 2003 U.S. Department of Energy Center of Excellence Award, the 2006 Ohio Governor’s Award for Excellence in Energy, the 2009 University of Dayton Alumni Award for Scholarship and the 2011 Champion of Energy Efficiency award from the American Council for an Energy Efficient Economy.

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Biographical Information

  • J. Kelly Kissock, Ph.D., P.E. Professor and Chair
  • Dept. of Mechanical and Aerospace Engineering /

Renewable and Clean Energy University of Dayton Kettering Laboratories 361-B, 300 College Park Dayton, OH 45469-0238 937-229-2835 Fax: 937-229-4766 kkissock@udayton.edu

  • Dr. Kissock is a Professor and Chair of the Mechanical and Aerospace

Engineering and Director of the Renewable and Clean Energy program at the University of Dayton. He is also Director of the University of Dayton Industrial Assessment Center. He is a Registered Professional Engineer in the State of Ohio. Dr. Kissock works in the fields of building, industrial and renewable energy systems. He has published

  • ver 100 technical papers on energy efficiency and renewable energy

and conducted seminars on energy efficiency across the world. Dr. Kissock served as Associate Editor of the ASME Journal of Solar Energy Engineering and has chaired several technical committees and

  • conferences. His work has been recognized with two Distinguished

Educator Awards by Who’s Who Among America’s Teachers, the 2003 U.S. Department of Energy Center of Excellence Award, the 2006 Ohio Governor’s Award for Excellence in Energy, the 2009 University of Dayton Alumni Award for Scholarship and the 2011 Champion of Energy Efficiency award from the American Council for an Energy Efficient Economy.

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Smart Building Data Analytics for Cooling Plants

Kelly Kissock

Department of Mechanical and Aerospace Engineering / Renewable and Clean Energy University of Dayton, Dayton Ohio, U.S.A. jkissock1@udayton.edu 937-229-2852

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Think Inside-Out

Energy savings increase as move from “inside out”

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Buildings: Upgrade Lighting and Windows

Lighting: LED with occupancy and dimming controls Windows: Low SHCG or electrochromic that vary solar heat gain coefficient (SHGC)

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Manufacturing: Reduce Heat Gain Into Cool Spaces

“about 3% of total cooling is to cool the

product…. 97% is for removing heat from internal loads, infiltration and conduction”

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Current: Qh1 = 100 Qc1 = 100 With HX: If Qhx = 30, Qh2 = 70 Qc2 = 30 HX reduces both heating and cooling loads!

Add HX Between Heating and Cooling

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Improve Air Handler Control Constant-Air-Volume to Variable-Air-Volume

CAV reheat box VAV box without reheat

Return Air Fan Cooling Coil Supply Air Fan VAV Box Interior Zone 1 Qsen1 VAV Box with Reheat Exterior Zone 2 Qsen2 Tsa Tma Filter 2 way valve CW Return CW Supply 2-way valve HW Supply HW Return Qlat1 Qlat2 Tz1 Tz2 Mixed Air Damper Outside Air Damper Exhaust Air Damper

VSD P

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CAV to VAV Cooling, Heating and Fan Savings

Constant-Air-Volume mixes hot and cold to meet zone load Variable-Air-Volume varies air flow to meet zone load Cooling savings = 40% Heating savings = 40% Fan Savings = 50%

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Improve VAV Fan Speed Control

Critical Zone Reset Control Fan Outlet Control Supply Duct Control

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VAV Fan Speed Control Strategies

B: Fan outlet C: Supply duct D: Critical zone reset

P V A B V2 = V1 / 2 V1 C D

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Reduce Static Pressure Setpoint

Baseline: Pset = 1.5” Dampers 65% Open Post Baseline: Pset = 1.0” Dampers 67% Open

Savings: 26%

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Employ Robust Critical Zone Reset

51% fan energy savings

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Improve Outdoor Air Control with Temperature-Based Economizer

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Identify Economizer Problems Using Temperature Data

Foa = (Tma – Tra) / (Toa – Tra)

Broken Functional

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Convert from Constant-Flow to Variable-Flow Pumping

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Savings from Constant Flow to Variable-Flow Pumping

A B

Wsav = W1 - W1 (V2/V1)3 Wsav = (17 hp -7 hp) / 17 hp = 59%

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Improve VSD Pumping Control

P V A B V2 = V1 / 2 V1 D A: B: C: D: C

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Chiller Control

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Increase Leaving Water Temperature at Low Loads

Increasing leaving water temperature at low loads from (45 F and 0.92 kW/ton) to (60 F and 0.80 kW/ton) saves 13%

kW/ton decreases as LWT increases Reset LWT with Toa

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Chiller Efficiency Varies with Load

Constant-speed: efficiency decreases as load decreases Variable-speed: efficiency increases as load decreases

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Constant-Speed Chillers: Run Fewest Possible

Running 1 chiller at (60% load and 0.30 kW/ton) instead of 2 chillers at (30% load and 0.37 kW/ton) saves 19%.

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Variable-Speed Chillers: Run Maximum Possible

Running 2 chillers at (40% load and 0.22 kW/ton) instead of 1 chiller at (80% load and 0.27 kW/ton) saves 19%.

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Variable + Constant-Speed Chillers: Employ Controller So Variable is Always Trim

Size VS at 125% of next biggest chiller to avoid control gaps. Saves 5-10%

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Cooling Tower Control

Fill Fill Sump AIR IN AIR IN WARM AIR OUT Hot Water Distribution Air Inlet Louvers HOT WATER IN HOT WATER IN COLD WATER OUT

Forced-air towers use more fan energy then induced-air towers. Evaporation rate = 0.30% to 0.75%. Evaporated water qualifies for sewer exemption.

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Select Energy-Efficient Cooling Towers

Base Tower Efficient Tower Fan rated hp (RP) 40 15 Fraction loaded (FL) 0.8 0.8 Moter efficiency (Em) 0.9 0.9 kW/hp 0.75 0.75 Hours per year (HPY) 6,000 6,000 $/kWh 0.1 0.1 Energy Cost ($/yr) = RHP x FL / Em x kW/hp x HPY x $/kWh 16,000 $ 6,000 $ Annual Savings ($/yr) 10,000 $ Tower lifetime (years) 10 Total Savings 100,000 $

Bigger towers cost more but reduce fan energy by 62%, saving $10,000 per year on $20,000 tower.

Source: Variable Flow Over Cooling Towers, Marley

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Install/Select VFDs on Cooling Tower Fans

10 F temperature drop and an 80 F set-point temperature Constant-speed fan is

  • n 47% of year

Variable speed runs at average of 37% of full speed. Overall, fan energy was reduced by 64%.

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Set Cooling Tower to Min Condensing Water Temp

Decreasing cooling tower water set point from (70 F and 0.58 kW/ton) to (60 F and 0.50 kW/ton) saves 14%

kW/ton decreases as CWT decreases

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Run Maximum Number of Cooling Towers

CT capacity varies with fan speed 100% speed = 100% cooling capacity 75% speed = 75% cooling capacity 50% speed = 50% cooling capacity CT fan power varies with cube of fan speed ratio 100% speed = 100%3 = 100% hp 75% speed = 75%3 = 42% hp 50% speed = 50%3 = 12% hp

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Cooling Tower Control: Full Load: 3 Towers: Fan power = 60 hp

900 gpm 20hp 900 gpm 20hp 900 gpm 20hp 300 ton 900 gpm 300 ton 900 gpm 300 ton 900 gpm

60 hp

10 hp 10 hp 10 hp

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Cooling Tower Control: 2/3 Load: 2 Towers: Fan Power = 40 hp

900 gpm 20hp 900 gpm 20hp gpm 0hp 300 ton 900 gpm 300 ton 900 gpm 0 ton 0 gpm

40 hp

10 hp 10 hp 0 hp

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Cooling Tower Control: 2/3 Load: 3 Towers: Fan power = 18 hp

600 gpm 6hp 600 gpm 6hp 600 gpm 6hp 300 ton 900 gpm 300 ton 900 gpm 0 ton 0 gpm

18 hp At part load operate all cooling towers: 40-18 = 22 hp

10 hp 10 hp 0 hp

FP2 = FP1 (V2/V1)3 FP2 = 20 (2/3)3 = 6 hp

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Cooling Tower Control: 1/3 Load: 3 Towers: Flow less than 50%

300 gpm 1hp 300 gpm 1hp 300 gpm 1hp 300 ton 900 gpm 0 ton 0 gpm 0 ton 0 gpm

3 hp! Don’t run CTs at less than 50% water flow: Dry Tower Syndrome

10 hp 0 hp 0 hp

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Use Cooling Tower During Cool Months

Fraction of year cooling tower can deliver water at Tc

Tc (F) Twb (F) Fyr (%) 75 65 72% 70 57 61% 65 50 53% 60 42 40%

CoolSim calculates number hours CT delivers target temperature.

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Case Study

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Eliminate Flow Through Inactive Chiller

45 F chilled water from the active chiller combined with 55 F water from the inactive chiller to create 50 F supply water. Installing isolation valves: 1) enabled chilled water leaving temperature to be increased from 45 F to 50 F 2) decreased pumping energy Savings = 163,000 kWh/yr (16% reduction of total pump and chiller energy)

Chilled Water Leaving Temp

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Eliminate Bypass to Reduce Pumping

Savings = 52,619 kWh/yr (51% reduction of pump energy use)

Time Series

  • f

Chiller and Pumping Power

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Stage Chillers Based on Load

300-ton constant speed chiller operates when Toa < 65 F 500-ton variable-speed chiller operates when Toa > 65 F. Variable speed chiller is more efficient at part load. Stage chillers based on load rather than outdoor air temperature. Savings = 81,000 kWh/yr (14% reduction of chiller energy usage)

kW/ton vs Load

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Reset Cooling Tower Supply Temperatures and Run Both Cooling Towers

Condenser water supply temperature set at 85°F and run only one tower with each chiller Chiller spec sheets indicated coldest allowable condenser water supply temperature is 65°F. Reset cooling tower supply temperatures to 65 F and run both cooling towers Savings = 45% reduction of chiller plus fan energy usage

kW/ton vs Load

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Goals

  • Help industry be more

resource‐efficient and cost‐ competitive

  • Train new energy engineers
  • Advance practice and science
  • f energy efficiency

Sponsored by U.S. Department of Energy

  • Began during 1970’s “energy crisis”
  • 28 centers at universities throughout the U.S.
  • 20 no‐cost assessments per year for mid‐sized

manufacturers

Industrial Assessment Center Program

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University of Dayton Industrial Assessment Center

Conducted 1,000+ FREE Assessments since 1981

  • Savings opportunities: 12
  • Simple payback: 2 years
  • Identified savings: 12%
  • Implemented savings: 6%
  • Please contact me if interested
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Thank you!

Kelly Kissock

Department of Mechanical and Aerospace Engineering / Renewable and Clean Energy University of Dayton, Dayton Ohio, U.S.A. jkissock1@udayton.edu 937-229-2852