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Strategies for Reducing Energy Usage in Your Labs by up to 50% Vytenis Milunas Director of Project Management University of Illinois - Chicago Daniel L.

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Presentation on theme: "Strategies for Reducing Energy Usage in Your Labs by up to 50% Vytenis Milunas Director of Project Management University of Illinois - Chicago Daniel L."— Presentation transcript:

1 Strategies for Reducing Energy Usage in Your Labs by up to 50% Vytenis Milunas Director of Project Management University of Illinois - Chicago Daniel L. Doyle Chairman Grumman/Butkus Associates

2 This presentation will discuss some general strategies for designing and operating high performance, energy-efficient laboratories. The air handling systems usually account for the largest amount of energy usage in a lab and are therefore the most important component of an energy- efficient system. First, airflow should be reduced as much as possible. Strategies such as reducing cooling loads in the space, reducing the air exhausted by fume hoods and other exhaust sources, and reducing the required air change rate of the space will be discussed. Strategies that can further reduce energy use, including demand-controlled ventilation and energy recovery systems, will all be discussed. Course Description

3 Learning Objectives 1.Identify energy efficiency considerations for laboratory planning 2.Identify ways to reduce cooling loads with efficient equipment and lighting 3.Describe the process for determining the required airflow to a space and strategies to reduce this airflow 4.Summarize options for reducing the energy required for cooling and reheat 5.Understand additional elements of high performance laboratory design 6.Summarize best practices strategies to achieve energy usage reduction of up to 50% At the end of the this course, participants will be able to:

4 Laboratories are energy intensive. Labs21 data indicates that labs consume about 3-8 times as much energy as a typical office building. On some campuses, labs consume two- thirds of total campus energy usage. Most existing labs can reduce energy use by 30% to 50% with existing technology. Reducing laboratory energy use will significantly reduce carbon dioxide emissions. 4

5 Reduced operating costs. Improved environmental quality. Expanded capacity. Increased health, safety, and worker productivity. Improved maintenance and reliability. Enhanced community relations. Superior recruitment and retention of scientists. 5

6 6 This presentation provides specific strategies that can result in energy efficient and eco-friendly laboratory designs; reducing energy use by as much as 50% as compared to a laboratory designed to comply with ASHRAE Standard 90.1 Exhaust System Optimization Demand-Controlled Ventilation Low Pressure Drop Design Air-To-Air Energy Recovery Strategies

7 7

8 Incorporate lowest cost/highest energy savings features first. 8

9 High efficiency fluorescents (T5s, T8s) and LEDs Occupancy sensors Dimming/bi-level switching to take advantage of daylighting

10 Use Energy Star equipment Use only EnergyStar rated equipment for things such as small refrigerators and desktop electronics. All new PCs, printers at UIC are Energy Star rated 10

11 Much more efficient freezers are now available Ultra-low temperature freezers with Stirling Engines; 30% to 50% savings – I2SL Webinar available on website Minimize the number of freezers and other large energy consuming equipment Centralize to allow to be shared by the maximum number of labs. 11

12 Lab Planning Strategies Minimize number of hoods Minimize size of hoods Can a 4 suffice in lieu of a 6 Use low flow/high performance hoods

13 Determine driver of lab airflow rate - Largest of 1.Make-up air required to offset the total exhaust (fume hoods, snorkel exhausts, some type of bio-safety cabinets). 2.The airflow required to adequately cool the space. 3.The required lab air change rate UIC: 8 ach 13

14 14 Make-up air driven: Total exhaust = sum of exhaust from all devices Fume hoods: Use maximum fume hood airflow - the airflow required when the face velocity is at its maximum and the sash is fully open. Reducing number: Install the minimum number of exhaust devices possible. Using low flow fume hoods

15 Lab Air Change Rates: The Labs21 Design Guide section on room air change rates states that: The conventional, "national consensus standard" has been 4 to 6 outside air changes per hour recommended for a "safe" B-occupancy laboratory Suggest using 4 ach maximum in standard laboratories. Consider increasing only when absolutely necessary; such as for carcinogenic materials. 15

16 AgencyVentilation Rate ASHRAE Lab Guides4-12 ACH UBC – cfm/ft 2 IBC – cfm/ft 2 IMC – cfm/ft 2 U.S. EPA4 ACH Unoccupied Lab – 8 ACH Occupied Lab AIA4-12 ACH NFPA ACH Unoccupied Lab – 8 ACH Occupied Lab NRC Prudent Practices4-12 ACH OSHA 29 CFR Part Recommends 4-12 ACH ACGIH 24 th Edition, 2001Ventilation depends on the generation rate and toxicity of the contaminant and not the size of the room. ANSI/AIHA Z9.5Prescriptive ACH is not appropriate. Rate shall be established by the owner!

17 Next we need to determine Airflow Required to Cool the Lab Thermal load calculations shall be performed in accordance with ASHRAE procedures 17

18 Minimize supply air required for cooling by: Using energy efficient lighting Using Energy Star equipment such as PCs, printers, copiers or refrigerators and freezers Using the most energy efficient lab equipment available Use equipment with remote (outside) heat rejection Do not overestimate the equipment load in the labs from which the thermal loads are calculated. Consider de-coupling cooling load: fan coils/chilled beams 18

19 Determine the Controlling Airflow Compare all three airflow requirements The largest airflow will determine the lab airflow requirements If the controlling airflow is significantly higher than the others, consider ways to further reduce the controlling airflow. 19 Fume HoodsLab Air Changes Thermal Load Final Requirements # of Hoods Exhaust Airflow per Hood Min Hood Make-Up Airflow Room Dimensions (WxLxH) Min ACH Min Lab Airflow Min Cooling Load Airflow Max Airflow driven by Min Lab Airflow Fume Hood Dominated 4600 cfm2,400 cfm40x20x cfm400 cfmhoods2,400 cfm Air Change Dominated 1600 cfm 40x20x cfm400 cfm min air change 800 cfm Thermal Load Dominated 1600 cfm 40x20x cfm1,200 cfm thermal load 1,200 cfm

20 Low flow hoods save significant energy, particularly in constant volume systems Good sash management (with VAV) is the most effective method of reducing flow, regardless of hood type Low flow hoods may be a good solution in buildings with limited HVAC capacity 20

21 Strategy to reduce cooling airflow: If thermal loads are high and driving the airflow, consider decoupling the thermal load from the room airflow by using water-based cooling: Chilled beams Fan coil units Be careful of condensation on chilled beams if humid air can enter the space. 21

22 Incorporate next highest level on the pyramid – still relatively low cost with high energy savings. 22

23 Airflow is actively modulated below the design maximum during part load or unoccupied conditions. Reduction is in response to certain criteria in the lab: Temp, sash position, air quality This reduces fan, heating, cooling and dehumidification energy consumption at the AHU. 23

24 Fume Hoods Use variable air volume (VAV) exhaust devices: Allows for reduction of flow when sash is not fully open or when hood is not in use. Consider occupancy sensors, auto sash closers Use VAV in combination with high performance (low flow) fume hood. 24

25 Specify ventilated cage racks in animal labs Lower room air change rates (from to 8 to 10) Provide better conditions for the animals Reduce frequency of cage changes 25

26 VAV terminal units (such as Venturi Valves) will be required on: Each fume hood Groups of snorkels Some bio-safety cabinets Supply air from AHU 26 General Exhaust Valve VAV Supply Air Valve Fume Hood Exhaust Valve

27 Demand-Based Ventilation Controls: Actively senses quality of air in labs by sensing for certain chemicals. Lab air change rates are reduced when not necessary to control air quality in lab. 27

28 Reduce air changes per hour (ACH) if no contaminants detected Increase air changes per hour (ACH) when contaminants detected 28

29 Incorporate third highest level on the pyramid – mid range cost with good energy savings. 29

30 95% MERV 14 Filter Typical Pressure Drops Filter TypePressure Drop (inches WG)* Std 12 inch deep box style rigid media filters inch deep low pressure drop V-bank type mini-pleat filters 0.37 Electronic filters0.20 *Initial clean filter pressure 500fpm

31 Up-size cross section of AHU to reduce face velocity and pressure drop across filters, cooling coils, etc. Traditional design: 500 fpm Low pressure drop design 300 fpm (or as low as space allows)

32 For a 10,000 cfm AHU, cross-sectional dimensions will increase from: 5 ft wide by 4 ft tall to 6 ft wide by 5.5 ft tall The net incremental cost is small Bigger sheet metal box Coils, filters are larger Motors, VFDs are smaller Can often eliminate sound attenuators, mist eliminators Simple reliable energy savings over the life of the AHU! Can never be overridden

33 Reducing pressure drop in AHU reduces the power required to drive the fan: Fan at 10,000 cfm and 7 w.g. static pressure 13.5 kW/18.0 bhp Fan at 10,000 cfm and 4 w.g. static pressure 5.8 kW/7.8 bhp

34 Options Analysis for 30,000 cfm AHU: Base Case (500 fpm): Pre and secondary filters, preheat coil, cooling coil, single centrifugal fan, conventional final filters, 5 sound attenuator Option 1 (400 fpm): Pre and secondary filters, preheat coil, cooling coil, fan array, low pressure drop final filters, 3 sound attenuators Option 2 (300 fpm): Pre filters, preheat coil, cooling coil, fan array, low pressure drop final filters, no sound attenuators

35 Design Static Pressure AHU First Cost Annual Energy Reduction as compared to Base Case Simple Payback ComEd Utility DSM Incentive Base Case (500 fpm) 8.5$150, Option 1 (400 fpm) 6.0$145,000$4,400 Immediate $3,655 Option 2 (300 fpm) 4.5$160,000 $10,200 Two months $8, fpm design in usually a no brainer! Between 300 fpm and 400 fpm will have a good payback

36 36

37 37 Slightly higher stacks, 4-5 feet controls Air quality sensor

38 Incorporate energy recovery: higher energy savings for higher cost. 38

39 Now required by IECC Energy Code Energy Recovery Requirements Chicago (Zone 5A) HR required if AHU>5,500 cfm and 30%4,500 cfm and 40%3,500 cfm and 50%2,000 cfm and 60%1,000 cfm and 70%80%

40 Wheels Enthalpy and desiccant Highest effective recovery Restrictions: not for hazardous exhaust Need adjacent airstreams

41 Heat Pipe Effective recovery Little maintenance No moving parts Requires less space than wheel

42 Plate Heat Exchanger Effective heat recovery Little maintenance Large Need adjacent airflows More commonly used for residential

43 Pumped Run-Around Glycol or Refrigerant Less effective recovery Maintenance required Airstreams can be far apart Most common option for retrofits

44 Real world example: Two 18,000 cfm 100% OA AHUs Heat pipe heat recovery Heat recovered from toilet exhaust Economics: Increased first costs: $40,000 Energy savings after 3 years: $50,670 Payback less than 3 years!

45 What are other high performing lab facilities doing? 45

46 University of California, Irvine: Smart Labs Initiative Goal: Outperform ASHRAE Standard 90.1/CA Title 24 by 50% On track to reduce electric usage by 20% from 2010 to 2012 Expect to reach 40% reduction by 2014 Combine initiatives such as: Demand controlled ventilation (DCV) Low flow/high performance fume hoods Reduced building exhaust stack airspeeds Energy efficient lighting 46

47 47 Current Best PracticeSmart Lab ParametersUIC Current Air-handler/filtration airspeeds400 ft/min. max350 ft/min. max FPM Total system (supply + exhaust) pressure- drop 6 in. w.g.<5 in. w.g. (incl. dirty filter allow.) 6 w.g. in purge 4 to 5 normal operation Duct noise attenuatorsFewNoneProject specific Occupied lab air-changes/hr. (ACH)6 ACH4 ACH w/ contaminant sensing 6 ACH (NIH min) 12 ACH (purge) Night air-change setback (unoccupied)No setback 2 ACH w/ occupancy + contaminant sensing + no thermal inputs during setbacks No setback Low-flow/high performance fume hoodsNoYes, where hood density warrantsProject specific Fume hood face velocities100 FPM70 FPM (low-flow hoods)80 FPM Fume hood face-velocities (unoccupied)100 FPM40 FPM (low-flow hoods) No unoccupied mode Fume hood auto-closersNoneWhere hood density highProject specific Exhaust stack discharge velocity~3,500 FPM Reduce or eliminate bypass air, wind responsive controls ~3000 FPM Lab illumination power-density0.9 watt/SF0.6 watt/SF w/ LED task lighting1.0 watt/SF retrofit buildings Fixtures near windows on daylight sensorsNoYesNo Energy Star freezers & refrigeratorsNoYes Out-perform CA Title %50%NA, use IECC

48 48 Vytenis Milunas Director of Project Management University of Illinois - Chicago (312) Dan Doyle, P.E., LEED AP Chairman Grumman/Butkus Associates (847)


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