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Achieving & Sustaining High Performance Building Operations December 2007 Bank of America Tower, NYC.

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Presentation on theme: "Achieving & Sustaining High Performance Building Operations December 2007 Bank of America Tower, NYC."— Presentation transcript:

1 Achieving & Sustaining High Performance Building Operations December 2007 Bank of America Tower, NYC

2 Todays Agenda Challenges with keeping buildings operating at peak performance An alternative approach Applications Re-circulated air systems 100% OA systems Benefits summary

3 The Rise of High Performance Buildings 3 trends are driving High Performance Buildings 1. Soaring energy costs 2. Rise of LEED & green buildings construction 3. Increased focus on indoor environmental quality (IEQ)

4 Tension between Ventilation & Energy Ventilation wants more outside air Energy Savings wants more return air

5 Trends Are Driving Increased Sensing Increased need for controls & sensors Min. outside air, DCV, economizers, pressurization, humidity control, etc. Controls require many sensors –CO 2, CO, T, RH, static pressure IEQ monitoring –Particles, TVOCs, formaldehyde, etc. Tighter sensor accuracies and proper application are major issues Inaccurate or mis-applied sensors can actually increase energy costs –Ex. - normal CO 2 errors waste energy

6 Unfulfilled Promise of Hi-Perf & LEED Bldgs High Performance Buildings idea is NOT new Demand Controlled Ventilation (DCV) Economizers Annual commissioning Failure has been in implementation (not design) 50% of all buildings are over ventilated – ASHRAE 70% of economizers dont work – New Buildings Institute Less than 5% of buildings are commissioned –ASHRAE Conventional approaches are not up to the task!

7 Conventional Approach Simple Reliable Cost Effective

8 Conventional Sensing Approach (Yikes!) Extra hard-wired points Sensor quality (accuracy) Sensor quantity (cost) Sensor maintenance & calibration BAS: knowledge vs. data

9 Conventional Sensor Approach Disadvantages High First Cost High quality sensors are required –Commercial grade often used but causes problems High cost of installation & integration –Hard wired BMS CO 2 or RH point: $1,000 to $1500/pt. Multiple sensors per location required for IEQ –Use of more than a couple sensors is cost prohibitive High Operating Costs Accuracy required often beyond sensor limits –Poor performance results = Lost energy savings High maintenance cost – Every sensor needs periodic calibration (1–3X/yr) HVAC systems degrade w/o optimization Lack of sufficient data & manual analysis costly

10 ASHRAE: Ventilation needs differential CO 2 measurement Conventional CO 2 Sensing ±75 PPM Error + ±75 PPM Error = ±150 PPM Error CO 2 set point must account for total error -If 500 PPM (20 CFM OA/person) is target: set point 350 PPM Due to sensor error, actual level can vary from 200–500 PPM Potential over-ventilation is huge! Up to 150% Even w/calibrated sensors, avg. OA can be 43% high! Potential energy penalty: ~$0.10–$0.20/ft 2 /year Return Air Sensor Outside Air Sensor Differential Measurement

11 At the 2007 ASHRAE IAQ Conference… Accuracy of CO 2 Sensors in Commercial Buildings: A Pilot Study Lawrence Berkeley National Laboratories 10% were dead: no output at all! Of the working sensors: 10% had negative errors (half off by more than 50%!) 90% had positive error (average positive error: +39%!) If DCV control was used: 10% would have the OA dampers fully closed The average OA airflow would be 260% too high! 20% would have the OA dampers at 100% OA!

12 LBNL CO 2 Field Sensor Study Results 10% Dead 81% Read High (avg. 39%!) 9% Low (½ by 50%)

13 LBNL: A Review of DCV; LBNL Michael G. Apte, Environmental Energy Technologies Division, Indoor Environment Department …data from the Iowa Energy Center showed long-term output from three self calibrating NDIR CO2 sensors operated side by side. Although these new sensors are guaranteed to hold calibration for five years, one unit was observed to have a positive baseline offset of 105 ppm compared to the other two that registered with 25 ppm at about 400 ppm. Nine months later, the baseline of the same unit had diverged by 265 ppm.

14 Conventional CO 2 Sensing Error Effects 23% Under-ventilation (650 PPM Δ) 20 CFM/Person: 500 PPM Δ Set Point 43% Over-ventilation (350 PPM Δ) Wasted Energy

15 Conventional CO 2 Sensing Error Effects 20 CFM/Person: +150 PPM Error 500 PPM based on 350 PPM Set Point 29 CFM/Person: 0 PPM Error at 350 PPM Set Point (43% Over-Vent) 500 CFM/Person: –150 PPM Error 200 PPM based on 350 PPM Set Point (150% Over-Vent) Wasted Energy

16 Californias Title 24 (coming in 2009) ALLOWS reduction of the minimum ventilation rates (15 CFM/person) IF the building is equipped with a demand control ventilation system. REQUIRES DCV on any HVAC system that: A.Has an economizer, AND… B.Serves a space with a design occupant density… 25 people per 1,000ft 2 (40ft 2 /person); AND… C.Is either single zone with any type of controls, or multiple zone systems with DDC. Exceptions: Classrooms, spaces with high exhaust, garage spaces, food prep areas, etc.

17 Californias Title 24 (coming in 2009) CO 2 Sensors For high density applications: requires a minimum of one sensor per 10,000 ft 2. Requires: minimum accuracy of ±75 PPM, factory calibrated, certified by the manufacturer to require calibration no more frequently than once every 5 years.

18 Economizers Control Method Dry Bulb Temperature –Outside air sensor versus fixed setpoint in design ASHRAE Std has max values from Differential Enthalpy Control –Same outside air and return air sensor for °F –Relative Humidity sensor for outside and return air Need High Quality or Expect Failure

19 Dry Bulb Economizer 55º F75º F OA is at Min OA is at Max OA/RA Mix

20 Differential Enthalpy Economizer 55º F OA is at Min OA/RA Mix h = 26.1 Btu/lbm 75º F/40% RH OA is at Max

21 Dry Bulb vs. Diff. Enthalpy Economizer 55º F OA/RA Mix 75º F/40% RH OA is at Min OA is at Max DB: OA is at Max DE: OA is at Min DB: OA is at Min DE: OA is at Max h = 26.1 Btu/lbm

22 Dry Bulb vs. Diff. Enthalpy Economizer 55º F OA/RA Mix 65º F OA is at Min OA at Max DB: OA is at Max DE: OA is at Min DB: OA is at Min DE: OA is at Max h = 26.1 Btu/lbm

23 Differential Enthalpy Economizer Savings City No Economizer 70º Dry-bulb Differential Enthalpy Madison, WI 0%11%27% Lake Charles, LA 0%3%9% New York, NY 0%12%33% Los Angeles, CA 0%51%76% Seattle, WA 0%25%51% Albuquerque, NM 0%3%22% Economizer Savings Study, ASHRAE No. 3200, 1989, P.C. Wacker, P.E.

24 Example 2: Differential Enthalpy Sensing Best economizer is differential enthalpy Savings increased by 15–100% over dry bulb type Comfort and IEQ increased as well Yet, dry bulb economizers dominate usage WHY? Enthalpy/humidity sensors are problematic High drift from outside air, low temp, particles, etc. –Sensors often hard to access & calibrate Differential measurement is prone to error –If sensor error is ±5%, total error of two sensors is ±10% –For a 10% RH difference, measurement error is ±100% Poorly working economizers waste $0.10–$0.50/ft 2 /yr

25 A New Approach: Multiplexed Air Packets BACnet to BAS Air Data Routers Sensor Suite Transformer Vacuum Pump Browser Interface Web Accessible Reports Knowledge Center Structured Cable I/O Particles TVOCs Dewpt CO 2 CO Internet Information Management Server

26 A New Approach: Multiplexed Air Packets BACnet to BAS Air Data Routers Sensor Suite Xfrmr Vacuum Pump Browser Interface Web Accessible Reports Knowledge Center I/O Internet IMS OA RA SA Conf. Lobby Office CO CO 2 Dew pt. TVOCs Particles

27 OptiNet Facility Monitoring System Aircuity Knowledge Center Web Browser OptiNet Structured cable Basement 1st floor 2nd floor 3rd floor Sensor Suite Air Data Router Local sensing point Internet Air Handler

28 Typical Room/Zone Layout Room 101Room 102Room 103Room 104 Structured Cable Air Data Router (ADR) To Sensor Suite To Next ADR

29 Optimizing Ventilation Zone ControlAHU Control Any building that has Economizer Dampers Any space that has VAV or 2-pos. Control Schools Offices Hospitals Labs & Vivariums Schools Offices Hospitals

30 Outside Air Applications Demand Control Ventilation DCV saves energy by decreasing OA Non-human pollutants override –If indoor air is dirty, OA increased Differential Enthalpy Economizer Control Saves energy by increasing OA Contaminated OA override –If outside air is dirty, OA reduced Particulate Control VAV ORs Data Centers Econ. Filter Validation OA Measurement 1 Sensor

31 Some Applications… Demand Controlled Ventilation CO 2, TVOCs, CO, Particles, Moisture Economizer Control Differential Enthalpy Particles & Humidity (Data Centers) Chilled Beam Control Dew Point Monitoring OA CFM Measurement Mass Balance Equation Lab/Vivarium DCV TVOCs/Particles & Ammonia Filter Validation

32 VAV for Operating Rooms

33 Ensuring Filter Performance 1Check and change filters often (open loop) 2 Check & Change filters; measure ΔP (open loop) 3 Change filters when needed; measure ΔP; monitor particulates (closed loop) ? ?

34 Data Center Economizers Most Data Centers use little (if any) OA RH and Particle concerns have been drivers OA can be used safely to achieve huge energy savings 7,000 ft 2 data center could save up to 230MWh/year!

35 OA Measurement using CO 2 Use Mass Balance Supply Air CO 2 equals the sum of the concentration of CO 2 in the OA and RA weighted by the percentage of those components of the supply air. Or… RA OASA

36 Multi-parameter Demand Control Ventilation Demand Control Ventilation DCV saves energy by decreasing OA Non-human pollutants override –If indoor air is dirty, OA increased Traditional DCV/CO 2 : waste energy or under-ventilate Single CO 2 set point: not the answer ASHRAE says more than CO 2 is needed Multi-parameter DCV provides Better ventilation More energy savings

37 OA Need Based on Design Occupancy CFM/person = 12,000 CFM

38 Single Set point Wastes Energy Excess OA = Wasted Energy Shoulder periods

39 OA Need Based on TVOC Events Not periodically predictable Need more OA than required by occupancy

40 OA Requirements for ASHRAE DCV What happens if only CO 2 is used?

41 Max Vent Usually Becomes OA Set Point

42 Potentially Huge Energy Savings Excess OA = Wasted Energy = Savings Potential

43 Over-Ventilation: A Real Example

44 Room Level Airflow Control Applications Simple dynamic override cuts across all markets Reduce room airflow min when CO 2 and contaminants are low Increase airflow when CO 2 or contaminants are high Reduces both fan power & htg/clg costs from OA Particularly appropriate for multi-zone air handlers Sample applications Use for DCV control of critical zones in offices, schools, etc. –Critical zones are rooms w/lower supply air & higher occupancy –Reduces AHUs outside air volume beyond AHU only control Reduces outside air dramatically in labs and vivariums Vary airflow use in hospital ORs when unused Dynamic Control of Min Ventilation & Fresh Air

45 VAV vs. OA

46 Another Application: Humidity Control Replace local RH sensor w/multiplexed dewpoint sensor Applications at the air handling unit –Humidity control of outside & mixed return air Applications at the room/zone level –Supplemental humidity control in ORs, animal rooms, offices, etc. Multiplexed dewpoint sensing has many benefits More accurate – Uses high quality sensor More reliable – Calibration is cost effective & regular More cost effective – One vs. many sensors

47 Demand Controlled Ventilation In Labs Safety of Occupants Primary Belief in High Air Changes per Hour (ACH) as a Dilution Strategy for Poor Lab Practices Limited Confidence in Distributed Sensing Capability & Calibration Cost (first and operating) Why we have not done this to date:

48 Current Drivers of Lab Airflow Hood & thermal airflows are reduced; vary for peaks Higher dilution requirement is typically the driver Ventilation Rate (CFM) VAV Fume Hoods Thermal Load 6-12 ACH 2- 4 ACH ACH/ Dilution Constant

49 Trends in Laboratories VAV Fume Hood Control has gained wide acceptance Fume hood densities are much lower More computation & lower chemical quantities Increased number of life sciences labs Thermal loads have peaked & are dropping Plug loads down from energy efficient equipment Higher efficiency lighting & more day lighting Energy costs are soaring LEED labs

50 Typical Life Sciences Lab

51 Low Load (blue) Medium Load (yellow) High Load (red)

52 AZ Lab Trend Findings Lab Min Vent CFM range: 9–16 ACH (Avg ~14) : Max Cooling CFM: 10–21 Watts/ft 2 (Avg ~14) Many Min Vent CFM Max Cooling CFM –Almost no VAV activity 71% always at min vent Mixed fume hood sash positions Always in Reheat (Low Load) Always Full Cooling (High Load) Mixed Clg/Reheat (Medium Load) 81% 14% 5%

53 Yet Requirements Stay The Same Minimum air changes still fixed at 6 to 12 ACH Need still exists for dilution ventilation in labs Dilute vapors from a spill when lab is unoccupied Dilute vapors & gases caused by poor lab practices –Working outside the hood –Improper storage of chemicals –No localized exhaust for instruments –Overworking & overcrowding of hoods Dilution: a backup to containment Fortunately, for most labs, room air is often clean

54 Actual Lab IEQ Case Study Major University laboratory facility 15 labs monitored continuously for 10 months Ventilation rate at 12 ACH per university IH group Result Two recorded incidents of elevated TVOC levels in several laboratories totaling 4-5 hours (0.07% of total hours) 99.93% of the time, these labs could have been operated at lower airflow rates Cause Workers using fume hoods during scheduled hood maintenance periods Solution Better internal communication between maintenance and occupants – No further incidents

55 Actual Data: 35 Days at 2 Facilities

56 Labs Are Clean MOST of the Time!

57 Actual TVOC Data: 35 Days of 2 Lab Zones Control Setpoint Range

58 Lab Demand Controlled Ventilation (DCV) Varies dilution/min ACHs by sensing lab IEQ If lab air is clean, dilution airflow can be reduced Plus, greater lab dilution is provided when needed by sensing or manual override Most lab controls can vary min ACH levels Critical piece: Sensing of IEQ parameters Lab TVOCs, Particles, RH, CO, & CO 2 Barriers to date: Cost & practicality Sensor cost Long term reliability Calibration of Distributed Sensors

59 Solution: Vary Dilution to Save Energy Lab DCV: Next generation lab airflow control Apply VAV control, to all lab air requirements Significantly reduce energy, find a way to increase safety Ventilation Rate (CFM) VAV Fume Hoods Thermal Load 6-12 ACH 2- 4 ACH Energy & First Cost Savings ACH/ Dilution VAV

60 Lab Quality Sensed Parameters Air Cleanliness Total Volatile Organic Compounds – PID sensor Particles – laser based particle counter Carbon Monoxide (CO) Comfort & Ventilation Temperature Humidity – Dew point Hygrometer Carbon Dioxide (CO 2 ) Future Sensors Air Acidity (PH) Ammonia Differential Static pressure Formaldehyde Chemical & Biological agents

61 LAB IEQ Monitoring Increases Lab Safety Validates the safe operation of a lab Detect improper bench use of chemicals Detect poorly containing fume hoods Spills, fires, & rogue reactions rapidly sensed Check lab pressurization (future), temp & RH Allows for safer lab airflow control Increased hood capture from reduced drafts –Drops room flows when dilution not needed Greater dilution provided for spills, leaks, etc. –12–15 ACHs can be provided automatically Sources of leaks & emissions can be found With fact based data, source controls can be used

62 Dynamic Control of Dilution Rates 1.5 L spill of acetone in 200ft 2 lab Total PPM is lower with dynamic ventilation After vaporized, dynamic system hits TLV faster After 1 hour Dynamic control has dropped level to.53 PPM

63 Dynamic Dilution Ventilation Control There is no need to dilute clean air w/ clean air TVOC, particle counter, etc. sense air –Hundreds of compounds are detected below TLV threshold –Small number of compounds not detected are fairly dangerous Should not be used in a fume hood Set min dilution levels per OSHA or as desired For high concern: 4 ACH occupied; 2 ACH unoccupied –OSHA guidelines have a minimum at 4 ACH (range of 4–12) For less severe applications, use 2 ACH as minimum –ASHRAE fresh air min for science lab is 0.18 CFM/ft 2 or 1.2 ACH –Appropriate for life sciences & less critical lab and support areas Set max dilution level at 12–16 ACH for safest purge Or as high as the supply/exhaust valves can go

64 ASU Biodesign B – Aircuity Results Average Savings: 10,636 CFM At $6.00/CFM annually = $63,816 per year = $7.98/ft2 per year = 9 month payback! New Average Supply: 5,229 CFM Old Average Supply: 15,978 CFM 10,636 CFM Savings June 4, 2007 Aircuity Activation

65 Chilled Beams in Labs Multiplexed dewpoint sensing benefits: More reliable –Calibration is cost effective –Calibration regularly done More accurate – Uses high quality sensor –(NDIR hygrometer) More cost effective –1 vs. many sensors Reduced Costs –Smaller T

66 Average Dewpoint Levels For all Sites High lab dewpoint levels could create condensation on chilled beams w/o dewpoint sensing & control

67 DCV Case Study: GreenLab, Seattle Project Facts Project team: –Owner – Vulcan (Paul Allen) –Architect – Perkins & Will –Mechanical Eng. – Stantec (Keen Eng.) –Contractor – Sellen –Estimator – Davis Langdon 215,000 ft 2 mixed use building –75,000 ft 2 lab area –75,000 ft 2 office –25,000 ft 2 optional vivarium Design based on Aircuity Lab DCV

68 DCV Case Study: GreenLab, Seattle Lab DCV analysis assumptions: Lab area: 4–16 ACH vs. a fixed 9 ACH Vivarium: 8–16 ACH vs. a fixed 15 ACH Gross first cost savings: $1,025,000 $13.68/ft 2 gross or $8.68/ft 2 net for lab Total bldg energy cut by $250,000/yr. Reduced total bldgs utility bill by 20% ROI: 1.5 yr energy payback Single greatest energy savings measure of the project

69 Harvard Allston Lab Project Annual Energy Savings Energy Savings for 350K ft 2 Lab$528,360 Energy Savings for 50K ft 2 Vivarium$275,200 Total Annual Savings$803,560 Total Installed Optinet System Cost Research Lab OptiNet system cost$750,000 Vivarium OptiNet system cost$185,000 Public Area OptiNet system cost$75,000 Labor assumed at 35% of materials$355,000 Total Installed OptiNet cost$1,365,000 Simple Payback

70 Brigham & Womens Hospital Example Annual Energy Savings: Floors 1 – 3 Fan power savings$40,414 Floors 1 – 3 Outside Air savings$41,344 Diff enthalpy vs. dry bulb economizers$58,788 Total Energy Savings$140,546 Total Installed System Cost Material & Startup costs$96,000 Deduct for 15 CO 2 sensors- $18,000 Deduct for 10 RH sensors- $10,000 Installation cost$38,000 Total adjusted installed cost$106,000 Simple payback on above scope0.76 years 5 Year lifecycle analysis results+$504,235 Assumes annual services of $18,500/yr

71 Aircuity at UC San Diego, Center Hall University Classroom Bldg. 2,100 Student Facility Applied MpDCV Net 1 st Cost: $29K Saves over $38,000/year in energy 45% of annual HVAC energy! Saves 310,000 Kwh & 1,100 MBTU 9-Month Payback 5-Year savings nearly $200K

72 Aircuity at Bank of America Tower, NYC 1 st LEED Platinum Skyscraper JB&B, NYC Specified Aircuity $1.0B budget, 2.1M ft 2 building 40 Suites vs CO 2 sensors Saves $160K/year in maintenance Saves $400K in replacement costs Every 2-5 years! One Bryant Park

73 Aircuity at UBS in Stamford, CT Worlds largest open securities trading floor Aircuity Energy Retrofit Van Zelm Engineers, CT 1.7 year energy payback

74 Aircuity at the Newark Arena (NJ Devils) 100,000 ft 2 sports arena; $310M budget Vanderweil Associates; Flat specified Aircuity Demanding Dew Point & DCV control Multiple IEQ Parameters Project 1 st Cost reduced by over $100K ($1/ft 2 ) Saves $40,000/year in maintenance Saves $90K in sensor replacement costs Every 2-5 years

75 Some Laboratory/Vivarium Customers Harvard School of Public Health Merck Research Labs Grand Valley State Univ Acadia Univ Univ of Cincinnati Arizona State Univ Rice Univ Texas Childrens Hospital Childrens Hospital of Philadelphia Case Western Reserve Univ Regina Provincial Labs

76 Some Commercial Applications Customers Yale Univ NYU Medical Center Boston Univ Univ of Nevada – Las Vegas Carnegie Mellon Univ Boeing UBS Financial St. Francis Hospital Bristol Myers Squibb Brigham & Womens Hospital Packard Humanities Inst. Film Vault New Jersey Devils Arena Bank of America

77 Cost Effective LEED NC Points Primary impact on up to 4 points: IEQ potential: 3 pts. EQ - 1 : Permanent CO 2 /OA Monitoring EQ - 3.2: Construction IAQ Mgmt Plan EQ - 7.2: Permanent Comfort Monitoring Innovation in Design potential: 1 pt. Comprehensive IEQ Mgmt System –Multi-parameter DCV

78 Cost Effective LEED NC Points System can assist/lower cost on up to 13 pts: Energy & Atmosphere potential: 12 pts. EA - 1: Optimize Energy: up to 10 pts. EA - 3 Enhanced Commissioning: 1 pt. EA - 5 Measurement & Verification: 1 pt. IEQ potential: 1 point EQ - 3.1: Construction IAQ Mgmt Plan: 1 pt. Facility monitoring can impact up to 15% of LEED points

79 Review Traditional technology has many shortfalls in the quest for long-term high performance building operation Now a solution exists to ensure that buildings satisfy both owners and occupants OA management and associated sensors are key factors The benefits are measurable and can be substantial

80 Aircuity Summary An alternative approach for sustainable control Cost effectively improves OA efficiency Key Benefits Energy savings –5-50% annually Reduced labor & operating costs –20-40% annually Improved IEQ –Increased productivity, peace of mind LEED Points Actionable information –Gives you the power to keep your facilities operating at a high performance level today AND tomorrow.

81 Aircuity Summary An alternative approach for sustainable control Cost effectively improves OA efficiency Key Benefits Energy savings –5-50% annually Reduced labor & operating costs –20-40% annually Improved IEQ –Increased productivity, peace of mind LEED Points Actionable information –Gives you the power to keep your facilities operating at a high performance level today AND tomorrow.

82 A New Approach: Multiplexed Air Packets BACnet to BAS Air Data Routers Sensor Suite Xfrmr Vacuum Pump Browser Interface Web Accessible Reports Knowledge Center I/O Internet IMS OA RA SA Conf. Lobby Office CO CO 2 Dew pt. TVOCs Particles


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