SELECTION FOR SUSTAINABLE

Transcription

1 BASIC FAN SELECTION FOR LEED & SUSTAINABLE DESIGN

2 Introducing Jerry Kiel, P.E. LEED AP Lockheed Martin SSC Waterton Campus Sn. Staff Mechanical Engineer, Tactical Operations FO&S. BSME, University of Missouri Rolla 1972 MSME, Colorado State University 1985 Past President Rocky Mt. Chapter ASHRAE (1985/1986) Region IX Energy & Technical Affairs Committee Chairman LEED AP BD+C, Colorado - CEM 40 years of HVAC consulting experience

3 HVAC FAN SYSTEMS Sustainable Buildings Are Highly Dependent Upon HVAC Fans For; HVAC comfort control, / humidification. Exhaust & fume hood control Room pressurization The efficient movement / transfer of air

4 BASIC FAN PHYSICS TSP = VP + SP CFM = Cubic Feet / Minute Standard air F 1 FT To select a fan you need the following: Volumetric flow (CFM) External static ti pressure (TSP) Fan location & duty Operating environment Fan construction, ti type, & materials

5 ALTITUDE CORRECTION Fan data is SL conditions i & 70 F 5000 ft. alt. = (0.075)(0.832) 075)(0 = F NOTE: If air temperature t changes, - correction factor changes. Computer programs can adjust air density for altitude & temperature.

6 ALTITUDE CORRECTION (Example) ft. alt. 1.5 esp. / = 1.80 espsl 3.53 bhpsl x = ft. alt. If t = ft > then cf = RECOMMENDATION: State conditions on schedule

7 FAN DESIGN THE FAN CURVE!

8 UNDERSTANDING THE FAN LAWS CFM varies directly with RPM CFM1 / CFM2 = RPM1 / RPM2 TSP varies with the square of RPM TSP1 / TSP2 = (RPM1 / RPM2 ) 2 HP varies with the cube of RPM HP1 / HP2 = ( RPM1 / RPM2 ) 3 WARNING! - Fans must be properly p selected for fan laws to be applied.

9 FAN CURVE TESTING & CERTIFICATION

10 UNDERSTANDING THE FAN CURVE RPM Curves Fan Selection Point The System (VAV) curve Peak Mechanical Eff. Break HP Curve The Unstable Region

11 FAN SYSTEM EFFECT The Effects of Errors in Estimating Fan System Resistance! Curve B Actual Duct System Actual System Pressure Loss More Than Design Fan Will Deliver At 2 Curve A Calculated Duct System 5 Peak Fan Pressure Curve C Actual Duct System Actual System Pressure Loss Less Than Design Fan Will Deliver At 3 D i Design Pressure Fan Pressure-Volume Curve Design Flow Rate Q

12 FAN WHEEL CONSTRUCTION Forward curved fan (FC) can overload TSP > 3.0 $ Backward inclined fans (BIF) SWSI or DWDI non-overloading TSP > 6.0 $$ Backward air foil (BAF) SWSI or DWDI high efficiency non-overloading TSP > $$$

13 FAN HOUSING CONSTRUCTION DWDI FAN WHEEL SWSI FAN WHEEL

14 TUBULAR FAN CONSTRUCTION MIXED FLOW FAN

15 UNDERSTANDING FAN CURVES A FORWARD CURVED OR SQUIRREL CAGE, FAN WHEEL

16 SWSI - AF WHEELS

17 PLENUM OR PLUG FANS

18 PLUG FANS! Good for plenums Need 24 min. to fan inlet Inlet vanes will add pressure drop Good for radial duct takeoffs Counter rotate if used in parallel CAUTION: Plug fans can have high internal SP losses.

19 PARALLEL FANS

20 FAN MATRIX / FAN WALL

21 FANS IN SERIES

22 FAN CLASSIFICATIONS AMCA wheel classifications: i, ii, iii, iv, v Based upon wheel diameter and RPM. Considers inertial and centrifugal forces. Effects fans shafts, bearings, belts, fan frame design, wheel construction metal gages, spring isolators, motors and fan belts.

23 CAN FAN SPEED BE INCREASED? CAUTION: Compare wheel RPM to wheel classification max RPM. CAUTION: Compare wheel starting torque to motor starting torque.

24 Mechanical System(s) ASHRAE

25 Fan Power Requirements Constant Air Volume = 0.94 bhp/1000 cfm + Allowances Variable Air Volume = 1.30 bhp/1000 cfm + Allowances VAV Offices 1.5 bhp/1000 cfm VAV Labs 2.3 bhp/1000 cfm Based on Break HP Includes fans operating at peak cooling load cfm Allowances for: (Added system static pressure) Ducted returns & dampered return control devices Filters (ASHRAE 62.1) Heat or energy recovery systems Duct silencers

26 ENERGY CALCULATIONS HP (1Ø) = V x A x Eff. X Pf / 746 HP (3Ø) = V x A x x Eff. X Pf. / 746 KW (3Ø) = V x A x Pf x / 1000 ASHRAE Sect. 6.5 (fan power limits)

27 FAN MOTORS ODP Open Drip Proof $ TEFC Totally Enclosed Fan Cooled $$ Premium Efficiency vs. Inverter Duty $$ Explosion Proof $$$ ASHRAE Table 10.8 (motor efficiency) i

28 FAN MOTORS (other issues) Motor starting torque service factor Belt & drive losses (4% > 8%) High, premium efficiency, and inverter duty Power factor correction (90%)

29 EXPLOSION PROOF FANS! CATASTROPHIC FAN FAILURE! TYPE A TYPE B TYPE C All parts in air stream shall be a non- ferrous metal (aluminum). $$$ Nonferrous impeller and rubring can have ferrous shaft but no metal to metal contact. $$ An impeller shift will not cause metal to metal contact. $ Recommendation: Electrically ground metal frame.

30 FAN VOLUME CONTROLS Inlet vanes High inlet losses precise control difficult Inlet cone Reduced inlet losses better volume control Outlet dampers High static pressure losses High noise 2500 FPM - HD damper

31 FAN VOLUME CONTROLS (cont.) VFDs - Includes starter and soft start May need manual by-pass Spec inverter duty motor Accurate speed control o Good for SF/RF tracking systems Controllable blades High first cost Maintenance concern Control accuracy fair-good LEED CREDIT EA 1.11 TO 1.10: 10: OPTIMIZE ENERGY PERFORMANCE

32 VARIABLE SPEED FAN CONTROL Exhaust air Return fan ROOM 1 ROOM 2 ROOM 3 ROOM 4 P P P Recirculation Cooling 4-20 ma Damper Outside air Filter Heating Supply fan P wg ADJ ma Line LEED CREDIT EA 1.1 TO 1.10: OPTIMIZE ENERGY PERFORMANCE

33 FAN TRACKING +/- PRESSURE Exhaust air Return fan ROOM 1 ROOM 2 ROOM 3 ROOM 4 P Recirculation Static Pressure Outside air Supply fan Cooling Heating E.M.S. Panel Do not use one drive or one control signal to control both supply and return fans Different Fan Curves!

34 FAN VIBRATION Natural Frequency Of Rotating Equipment Is the frequency at which the system prefers to vibrate. fn = 188 (1/d) ½ fn = ( cycles per minute ) d =(188/fn) 2 d=(static deflection in inches) Choose springs accordingly = (Wt + d) Quite fans are part of a sustainable building design!

35 FAN VIBRATION (cont.) A good spec for factory dynamic fan balance is 1.5 mils, or velocity, in./sec. (Peak to peak filtered) May need to be checked in the field Can fans be bolted directly to the floor? Yes! The entire structural system must be engineered and the fans specified must be of industrial (Dynamically Balanced), quality!

36 FAN SOUND POWER Fan sound power is the vibrational power a fan converts to sound, measured in watts. Fan sound power is produced by: Blade pass frequency Bearing noise Belt noise Air serge in fan casing & ducts (oil can effect)

37 FAN SOUND POWER (cont.) Fan sound power is transmitted by: Radiated energy from fan casing Discharge sound power transmitted down ducts Through structures, steel beams, walls, etc. Specify sound power in power levels (Lw scale) not (db scale) sound pressure. Fans need to be AMCA certified for sound

38 FAN SOUND POWER (cont.) There is no outright conversion between sound power levels & sound pressure! High & low octave bands are accurate to +/- 4 db Low frequencies are difficult to attenuate Sound power levels l are added d log rhythmically Lw = log (w / wo) db Quite fans are part of a sustainable building design!

39 ENERGY EFFICIENT FAN SYSTEMS SOUND ATTENUATORS ARE SHAPED & BUILT INTO THE FAN SYSTEM IMPROVED AIR FLOW, LOW NOISE,,& HIGH FAN EFFICIENCY. LEED EA-1.1 TO OPTIMIZE ENERGY PERFORMANCE

40 FAN - SYSTEM EFFECT A HEAT RECLAIM LOOP LEED EA-1.1 TO OPTIMIZE ENERGY PERFORMANCE

41 COIL HEAT TRANSFER THEORY GPM *504 (TH-TC) = BTUs / Hr = CFM *0.89 (TH-TC) FOR HEAT TRANSFER TO OCCUR, A MOLECULE OF AIR MUST STRIKE A COIL FIN OR PIPE SURFACE! CW OUT COOL AIR 53 F WARM AIR 82 F CW IN AIR FLOW Coil face velocities 400 to 500 fpm

42 RUN AROUND COILS HEAT TRANSFER BETWEEN TWO AIR STREAMS Hot to Cold CHECK COIL AIR & WATER P DROPS FOR PARASITIC HP LOSSES

43 HEAT PIPE - ENERGY RECOVERY

44 A HEAT PIPE POOL UNIT WITH A HUMIDIFICATION BY-PASS DAMPER HEAT PIPE COILS HUMIDIFICATION BY-PASS DAMPER LEED EA-1.1 TO OPTIMIZE ENERGY PERFORMANCE H

45 HEAT WHEEL AIR TO AIR ENERGY RECOVERY PACKAGED ENERGY RECOVERY UNIT LEED EA-1.1 TO OPTIMIZE ENERGY PERFORMANCE

46 FAN TEST & BALANCE & COMMISSIONING Fan T&B reports should contain: Fan and motor name plate information Measured voltage & amps (per phase) TSP across fan Fan RPM and checked for rotation Measured CFM location in duct) LEED EA-3 PRELIMINARY & ENHANCED COMMISSIONING Recreate The Fan Curve!

47 FAN AIR FLOW

48 FAN TROUBLESHOOTING! If fan has low CFM capacity or pressure, check: Fan rotation Poor fan inlet conditions Proper wheel alignment Material in fan wheel Duct connections Roof curb connections LEED EA-5 MEASUREMENT & VERIFICATION

49 FAN TROUBLESHOOTING! (cont.) If fan has excessive vibration and noise, check: Damaged or unbalanced wheel Belts loose, oily, too tight, damaged Speed too high Bearings failed, (VFD - Bearing Race Pitting) May Need Shaft Grounding Kits Fan surge (stall)

50 FAN TROUBLESHOOTING! (cont.) If fan has an overheated eated motor, check: Improperly p wired Cooling air diverted or blocked Improper inlet clearance Incorrect fan RPM Incorrect voltage

51 PRESSURE RELIEF DOORS FIRE / SMOKE DAMPER

52 THANK YOU! ANY QUESTIONS? Jerry Kiel, PE LEED AP

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54 ENERGY RECOVERY - NATATORIUMS

55 HOW DOES A POOL WORK? A pool cools & humidifies the air as water evaporates (It is an evaporative cooler!) The air conditioning system must heat and dehumidify the air to maintain the pool room temperature and humidity at the desired condition This occurs 24 hours a day, 7 days a week, 365 days a year THE POOL CAN BE AN ENERGY HOG! $$$ Evaporating Water POOL WATER

56 NATATORIUM ENERGY RECOVERY Natatoriums pose a difficult environment for HVAC systems. Requires heating and dehumidification 90% of cooling effect go to the air Humidity Ratio Grains of Moisture per Po ound of Dry Air (gr/lb) Dry Bulb Temperature F

57 Utility Rates = Energy Cost $$$ Note: LEED Points Are Based On Energy $$$ Saved, Not Necessarily BTUs, Saved! Obtain a Current Copy Of The Utility Rate Schedule For The Project s Location. Breakdown the rate for nat. gas, electrical, steam, district chilled water, CUP, cost, etc. Determine demand costs (KWs), energy costs (KWHs), & natural gas cost, ($ / therm or deca therm). Build a utility rate model, by fuel types, in the Energy Modeling Program.

58 Peak Demand Savings $14 to $16 / KW kw Heating / Cooling Pumps Fans Lighting 200 Base Load Hours of Typical Day Develop A LEED Point Strategy!

59 They Can Include Heating Coils, CW Coils, Energy Recovery, & or DX Coils, & Compressors