Auburn University Basketball Arena: How Building Data Analytics Achieved Energy and O&M Savings While Improving Comfort and Sustainability Eric Moore, PE, CEM, Auburn University Hadas Webb, CEM, Cimetrics IDEA 27th Annual Campus Energy Conference Atlanta, GA February 20, 2014
Agenda Auburn University & Cimetrics Collaboration Auburn Arena Background Case Study Findings: Fan speed control Dehumidification control Damper controls Heat exchanger modification Ongoing Commissioning Results Questions
Auburn + Cimetrics Collaboration University Sustainability Goals American College & University Presidents Climate Commitment (ACUPCC) Carbon neutral by 2050 Reduce campus energy intensity 20% by 2020 based on 2006 baseline Ongoing commissioning identified annual savings Energy: $444,276 CHW: 108,000 kgal CO 2 : 4,560 metric tons Steam: 1,150 mlb Electrical: 2,560 MWh Natural gas: 1,257 MCF HW: 31,000 kgal Cumulative savings of $900,000 and 29% reduction in MMBTU/ft 2 between 2008 and 2013
Auburn Basketball Arena Built in 2010 276,568 ft 2, $92.5 million facility 9,121 seat main court Use: Men's and Women's basketball, Women's gymnastics, music events, camps, commencements Additional space: practice courts, locker rooms, weight training, sports medicine, offices, suites & lounges, food prep and service, athletics museum Connected to central hot water and chilled water systems
Issues Identified Main court AHUs: Supply fan VFDs running at constant speeds Cooling valves 100% open in dehumidification mode Economizer optimization Building pressurization Domestic hot water heat exchanger configuration Chilled water pump differential pressure exceeding setpoint AHU operation improvements: Occupancy scheduling Static pressure setpoint reset Damper control Temperature control VAV operation improvements
Arena Data Collection & Reporting Building automation system (HVAC) data collection, analysis, and reporting by Cimetrics started in Sept. 2011: 2,145 total JCI points polled 24/7/365 15-minute polling frequency 7,798 computed points 200,000+ samples per day Equipment monitored and analyzed: 23 air handling units & 19 exhaust fans 5 hot water & chilled water pumps 100 terminal units Multiple system control valves
Main Court Supply Fan Speed Control Original Configuration: 2 fans at 100% AHU-4A-1 Fan Energy: 156,814 kwh Cooling Energy: 7,606 MMBTU Heating Energy: 4,868 MMBTU AHU-4D-1 Fan Energy: 248,882 kwh Cooling Energy: 8,790 MMBTU Heating Energy: 4,972 MMBTU
Main Court Supply Fan Speed Control Final Configuration: 4 fans variable speeds AHU-4A-1 Fan Energy: 15,900 kwh Cooling Energy: 2,444 MMBTU Heating Energy: 1,499 MMBTU AHU-4C-1 Fan Energy: 20,751 kwh Cooling Energy: 2,597 MMBTU Heating Energy: 1,594 MMBTU AHU-4B-1 Fan Energy: 22,109 kwh Cooling Energy: 2,625 MMBTU Heating Energy: 1,616 MMBTU AHU-4D-1 Fan Energy: 19,160 kwh Cooling Energy: 2,788 MMBTU Heating Energy: 1,665 MMBTU
Consumption (kwh) Main Court Fan Speed Control Results Arena Bowl Supply & Exhaust Fan Electrical Consumption 45,000 40,000 35,000 30,000 25,000 20,000 Control sequence update 72% decrease in kwh from 2011 to 2012 Increased summer usage under investigation 15,000 10,000 5,000 0 Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011 2012 2013 Total AHU Supply Fan Total AHU Exhaust Fans 184,500 kwh reduction over 7 month period $9,200 savings over 7 months $15,700 annualized savings 72% reduction in electricity consumption
10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19 19-20 20-21 21-22 22-23 23-24 24-25 25-26 26-27 27-28 28-29 29-30 30-31 31-32 32-33 33-34 34-35 35-36 36-37 37-38 38-39 39-40 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19 19-20 20-21 21-22 22-23 23-24 24-25 25-26 26-27 27-28 28-29 29-30 30-31 31-32 32-33 33-34 34-35 35-36 36-37 37-38 38-39 39-40 Signal (%), Temperature (F), Relative Humidity (%) Main Court Dehumidification Control AHU Dehumidification Control - Average Across 4 AHUs 100 90 80 70 Cooling valve signal of 100% when return RH > 55% Cooling valve signal = 47% Cooling coil discharge = 52 F Reheat valve signal = 32% 60 50 40 30 20 10 0 Cooling valve signal = 100% Cooling coil discharge = 50 F Reheat valve signal = 50% Cooling valve modulates to maintain return RH of 55% BEFORE Outside Air Enthalpy (BTU/lb) AFTER Cooling Valve Signal Cooling Coil Discharge Air Temperature Reheat Valve Signal Discharge Air Temperature Discharge Air Temperature Setpoint Return Humidity Return Humidity Setpoint
10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19 19-20 20-21 21-22 22-23 23-24 24-25 25-26 26-27 27-28 28-29 29-30 30-31 31-32 32-33 33-34 34-35 35-36 36-37 37-38 38-39 39-40 CHW Delta T (F) CHW Flow (GPM) Main Court Dehumidification Control AHU Dehumidification Control and Building Chilled Water 22 20 18 16 14 12 10 Average increase in primary chilled water delta T of 2.3 F 900 800 700 600 500 400 8 6 4 2 0 Average decrease in chilled water flow of 125 GPM 300 200 100 0 Outside Air Enthalpy (BTU/lb) Delta T - Before Delta T - After Flow - Before Flow - After
Main Court AHU Damper Control Issues Identified: Building Over Pressurization Mixed Air Temperature Control Economizer Potential High CO 2 Levels Improvements: Building pressure sensors Dampers now used to control building pressure, CO 2 levels, and mixed air temperature
Average Daily Flow (GPM) Average Daily Delta T ( F) Heat Exchanger Modification Issue Identified: Instantaneous domestic hot water heaters had three-way valves on primary side. 1400 1200 1000 800 600 Central Hot Water Plant Effect BEFORE AFTER 60 50 40 30 400 20 200 10 7/1/2012 7/3/2012 7/5/2012 7/7/2012 7/9/2012 7/11/2012 7/13/2012 7/15/2012 7/17/2012 7/19/2012 7/21/2012 7/23/2012 7/25/2012 7/27/2012 7/29/2012 7/31/2012 0 Average Daily Flow GPM Average Daily Delta T ( F) 0 Estimated Annual Savings: Central Plant - $10,000
Energy & Environmental Results Estimated results based on Cimetrics recommendations and Auburn University implementation Annual savings: $114,000 Annual carbon savings: 1,800 metric-tons CO 2 Energy intensity based on actual utility data 2010: 188,476 BTU/ft 2 2011: 165,950 BTU/ft 2 2012: 150,447 BTU/ft 2 2013: 151,290 BTU/ft 2
Special thanks to: Auburn Athletics Department Ken Martin Energy Engineer, Auburn Mike Harris Director of Utilities & Energy, Auburn Rick Mitchell Johnson Controls Karim Bibawi VP of Sales & Marketing, Cimetrics Mary Ellen Cantabene Chief Operating Officer, Cimetrics Dean Taylor Manager of Analytics, Cimetrics
Questions? Eric Moore, PE, CEM, Auburn University jem0028@auburn.edu Hadas Webb, CEM, Cimetrics hwebb@cimetrics.com IDEA 27th Annual Campus Energy Conference Atlanta, GA February 20, 2014