Death Spiral of a BuildingCase Study of the Natural History Museum Bldg.

Sarah Boll - DFCM UtahSanjiv “Sunny” Devnani, P.E. - kW Engineering

AIA Quality Assurance

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This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.

Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

2

Learning Objectives

Commissioning or Retro-Commissioning

3

1. Whole Building Approach2. Systems are interactive and interdependent3. Scope must be all encompassing4. Problem solving at the Fundamental Level

http://www.aia.org/education/

NHMU

4

NHMU Layout

5

Simplified Layout

Can

yon

South

North

Building Pressurization Basics

Can

yon

South

North

150 CFM100 CFM

25 CFM25 CFM

8

UnitOA

(CFM)RA

(CFM)SA

(CFM)Exhaust (CFM)

Pressure (CFM)

Air Handling Unit 1 100 1,000 1,100 - 100 Air Handling Unit 2 50 500 550 - 50 Subtotal 150

Exhaust Exhaust 1 100 (100) Subtotal (100)

Total 150 1,500 1,650 100 50

Air Balance Chart - OUTPUT

• Complex Design• 3X Energy usage and spend • Maintenance:

• Routine occupant complaints• Filters changed every 3 weeks ($1,700/week)

• Collection Rooms Humidity & Temp Control • >10% deviation• Tracking with ambient

Issues Plaguing Building Operation

9

-0.07 in. wc

Simultaneous Dehumidification and Humidification

12

0

20

40

60

80

100

Perc

ent O

n [%

]

Dehumidification

0102030405060708090

100

Perc

ent O

n [%

]

Humidification

NHMU Air Balance

13

Unit

Outside Air/ Fresh Air

(CFM)

Return Air

(CFM)Supply Air (AHU CFM)

Exhaust (CFM)

Pressure (CFM)

AHU-1 - - 16,000 - (16,000) AHU-2 15,000 18,667 3,000 - 30,667 AHU-3 In Override 40,000 8,000 40,000 35,000 (27,000) AHU-4 20,000 20,000 4,000 - 36,000 AHU-5 875 17,500 3,500 - 14,875 AHU-6 10,000 - 2,000 - 8,000 Subtotal 85,875 64,167 68,500 35,000 46,542

Exhaust Toilets 0 - Kitchen 36990 (36,990) Paint Booth 18000 (18,000) Subtotal 54990 (54,990)

Total Pressurization 85,875 64,167 68,500 89,990 (8,448)

Air Balance Chart - OUTPUT

Current Conditions & Test Case

Current ConditionsCheck Values

AHUSupply Fan SizeReturn Fan SizeRelief Fan SizeSupply Fan VFD Return Fan VFDRelief Fan VFDRelief DamperSupply Fan VFD Return Fan VFDRelief Fan VFDOA DamperOA CFMSupply Air FlowReturn Air FlowExhaust Air FlowOA LimitDDH

IDCFMCFMCFMHzHzHz%%%%%CFMCFMCFMCFMCFM

AHU-180,000- 060,00053.0- 025.250%88%0%42%0%- 070,666.67- 012,600030,000

AHU-215,00020,000- 0- 050.4- 00%0%84%0%0%- 0- 016,800- 0150000

AHU-340,0008,00035,00048.0- 0- 00%80%0%0%10%4,00032,000.00- 0- 0400000

TravelAHU-420,00020,000- 054.030.0- 00%90%50%0%5%1,00018,000.0010,000- 0200007,500

collAHU-517,50017,500- 060.048.0- 00%100%80%0%7%1,22517,500.0014,000- 09002,180

AHU-610,000- 0- 048.0- 0- 00%80%0%

Sanjiv Devnani: Sanjiv Devnani:This is a dummy value. There is no Return Fan. The supply air is just dumped into the space and becomes part of the overall RA in the bldg.0%100%10,0008,000.00- 0- 0100000

Day?Yes

BoothNo- 0

Toilets/HoodYes36,990

16,225146,16740,80049,59085,90039,680

OA + RASF + EX

57,025195,757

CFM(138,732)-243%

FPM100

Opening Area(1,387.32)ft2

Any Condition - Test Case - Select OA Damper Position between above settings for Day/NightCheck Values

AHUSupply Fan SizeReturn Fan SizeRelief Fan SizeSupply Fan VFD Return Fan VFDRelief Fan VFDRelief DamperSupply Fan VFD Return Fan VFDRelief Fan VFDOA DamperOA CFMSupply Air FlowReturn Air FlowExhaust Air FlowVFD OffsetOA LimitDDHModeling Notes

IDCFMCFMCFMHzHzHz%%%%%CFMCFMCFMCFMCFM(Limits for Modulation are described below)

AHU-180,000- 060,00012.0- 0- 050%20%0%0%0%- 016,000- 0- 00030,000OA= 0% as it is fed by AHU-2. SF VFD min of 20% speed with Delta of 18 hz or 30% with RF. RF can max out at 100%.

AHU-215,00020,000- 012.056.0- 00%20%93%0%100%15,0003,00018,667- 044150000Day: Max OA% = 75%, Min = 50%. During Night = 5%. SF min/max = 16 hz/60 hz. RF min = 12 hz, RF max (SF Hz-Offset hz))

AHU-3 In Override40,0008,00035,00012.060.0- 00%100%100%100%100%40,00040,000.008,00035,000.0048400000Day: Max OA% = 55% when Pt Booth is off. 100% when Booth on. During Night = 5%. SF min/max = 12 hz/60 hz. RF min (SF Hz+Offset hz),RF Max = 60 hz)

TravelAHU-420,00020,000- 012.060.0- 00%20%100%0%100%20,0004,00020,000- 048200007,500Day: Max OA% = 75%, Min = 50%. During Night = 5%. SF min/max = 12 hz/60 hz. RF min = 12 hz, RF max (SF Hz-Offset hz))

collAHU-517,50017,500- 012.060.0- 00%20%100%0%5%8753,50017,500- 0489002,180OA=5% fixed. SF min/max = 12 hz/60 hz. RF min = 12 hz, RF max (SF Hz-Offset hz))

AHU-610,000- 0- 012.0- 0- 00%20%0%

Sanjiv Devnani: Sanjiv Devnani:This is a dummy value. There is no Return Fan. The supply air is just dumped into the space and becomes part of the overall RA in the bldg.0%100%10,0002,000- 0- 00100000OA=0-100%. SF min/max = 12 hz/60 hz. No Return Fan Present)

Day?YesSelect Yes or No

BoothYes18,000Select Yes or No

Toilets/HoodYes36,990Select Yes or No

85,87568,50064,16789,99085,90039,680

OA + RASF + EX

150,042158,490- 0

CFM(8,448)-6%

FPM100

Opening Area(84.48)ft2

Air Balance Output

Consultant Name

Project Name

Project Location (City)

Air Balance Chart - OUTPUT

UnitOutside Air/ Fresh Air (CFM)Return Air (CFM)Supply Air (AHU CFM)Exhaust (CFM)Pressure (CFM)

AHU-1- 0- 016,000- 0(16,000)

AHU-215,00018,6673,000- 030,667

AHU-3 In Override40,0008,00040,00035,000(27,000)

AHU-420,00020,0004,000- 036,000

AHU-587517,5003,500- 014,875

AHU-610,000- 02,000- 08,000

Subtotal85,87564,16768,50035,00046,542

Exhaust

Toilets0- 0

Kitchen36990(36,990)

Paint Booth18000(18,000)

Subtotal54990(54,990)

Total Pressurization85,87564,16768,50089,990(8,448)

% Pressurization-6%

Schedule

AHU SUMMARY

Flow (cfm)Flow (cfm)

AHU-1100,000OSA Range0-15,000

AHU-215,000OSA Range-

AHU-340,000OSA Range0-40,000

AHU-420,000OSA Range300-20,000

AHU-517,500Min. OSA900

AHU-610,000Min. OSA0RELIEF FANS (RF)

Flow (cfm)(hp)(bhp)VFD #

SUPPLY FANS (SF)AHU 1 & 2

Flow (cfm)(hp)VFD #RF-260,0003025.515

AHU 1RF-520,00054.5428

SF-1a25,0003010AHU 3

SF-1b25,0003011RF-3a17,50032.9918Exhaust CFM

SF-1c25,0003012RF-3b17,50032.99192200

SF-1d25,0003013RF-68,00021.53302500

AHU 2AHU 45170

SF-215,0001514RF-120,00054.05225170

AHU 3AHU 53500

SF-3a20,0002516RF-417,50054.07251000

SF-3b20,00025173000

AHU 4DESICCANT DEHUMIDFIER (DDH)Booth18000

SF-4a10,00010Proces Flow (cfm)kW600

SF-4b10,00010AHU 1900

AHU 5DDH-130,00059.051700

SF-5a8,7507.5AHU 4950

SF-5b8,7507.5DDH-27,50013.45100

AHU 6AHU 5125

SF-610,0007.5DDH-34901900

AHU 7DDH-4490100

SF-78,5001DDH-51,200100

625

1850

AHU #ScheduleDayLocationZone 1Zone 2Zone 3Zone 4Zone 5Zone 6Zone 72900

124/7M-S3rd flr SLife SouthFirst PeopleLife NorthThe LandPast WorldsLakeNative Voices600

2n/aM-S3rd flr S1700

324/7M-S3rd flr NRM 4142RM 4159RM 4102RM 4112300

424/7M-S3rd flr N2 Exhibits?Total 54990

524/7M-S6th flrRM 4100RM 3103RM 4109Total w/o Booth36990

66 am - 6 pmM-S1st flrSnowmelt/??

724/7M-S2nd flr??Display Case

AHU #HTG SPCLG SP

16870

2

3

470

56666

680-88

77272

Sheet1

NameAgreementRate ScheduleService NoService DescService Address Line 1Service Address Line 2Rvn YearmonthReading DtReading CycleElapsed DaysKwOffkwOnkwKwhOffkwhOnkwhShkwhDSM ChargeTotal Invoice

UNIVERSITY OF UTAH1848199607500208NMT06135674211593004NEW MUSEUM NMS SOLAR 333 KW301  S  WAKARA  WAYSALT LAKE CITY  UT  841082013011/22/131533559        287700            514.0419728.73

2013022/20/131529488        238500            436.1716749.86PeriodReading DateDaykWhkWMonthly Cost$/kWhkWh/day% Diff (16 vs 15)

2013033/21/131529481        202500            364.6915257.13Pre/Baseline1/22/1333287,700559$ 19,729$ 0.06868,718

2013044/19/131529518        235500            394.617081.331/22/1433301,500532$ 20,508$ 0.06809,136

2013055/20/131531469        220500            401.0817361.281/22/1531294,000514$ 20,248$ 0.06899,484

2013066/19/131530477        211800            417.1418053.64Trial1/22/1631238,800434$ 16,859$ 0.07067,70381%

2013077/19/131530536        243300            473.9220502.22

2013088/20/131532571        264600            510.0422059.723%

2013099/19/131530571        267600            546.2222548.77

20131010/18/131529515        231300            548.3318476.48

20131111/19/131532507        269700            558.7918827.73

20131212/20/131531524        290400            591.9919942.39

2014011/22/141533532        301500            608.8320507.96

2014022/20/141529518        262500            556.4318748.52

2014033/21/141529557        264300            577.2919448.79

2014044/21/141531580        292200            621.0220917.05

2014055/20/141529580        277200            669.6622550.14

2014066/19/141530568        266100            679.9522895.62

2014077/21/141532530        297300            697.923498.29

2014088/20/141530564        247200            654.4722040.31

2014099/19/141530502        261900            638.2621496.07

20141010/20/141531507        278400            606.4120426.65

20141111/19/141530497        267000            559.1918841.2

20141212/22/141533531        297900            614.0720683.85

2015011/22/151531514        294000            601.1220247.923134400241563

2015022/20/151529511        249600            595.4318476.910.30.0770683384

2015033/23/151531499        265500            632.0218939.62940320$ 72,468.90

2015044/21/151529515        251700            622.3318650.27

2015055/20/151529526        269700            723.3721667.91

2015066/19/151530520        270000            752.0822525.07

2015077/21/151532543        282300            786.1923543.79

2015088/20/151530513        260700            73421985.31

2015099/21/151532485        250800            704.4821103.55

20151010/20/151529492        241800            631.8418934.44

20151111/19/151530491        245700            603.6118091.34

20151212/22/151533436        252600            580.3717397.15

2016011/22/161531434        238800            603.0416859.29

OA Dampers Closed

VAV w/RH

78°F 68°F72°F

OAT/RH = 60°F

SAT = 55°F

RH Valve Open

>90°F

• Thermostat senses that space is cold• Reheat valve opens• Boiler comes on, HHW pumps comes on. • Dehumidification system comes on• The occupants in the space are uncomfortable• Adjust thermostat to lower setting• Supply air to the VAV box• Chiller plant is turned on (CT/Pumps etc)• Reheat valve & VAV box damper opens more as the SAT is now

colder • Duct pressure reduces. • VFD on AHU ramps• Simultaneous heating and cooling

Death Spiral of a Building

Change in Building Pressure – Immediate Results

VAV w/RH

72°F 72°F72°F

SAT = 60°F

RH Valve Closed/Modulating OAT/RH = 60°F

AHU Fan Speed

Annual Electric Costs

20

$-

$5,000

$10,000

$15,000

$20,000

$25,000

$/M

onth

Natural History Museum of Utah

2015-162016-17

• HVAC operations can be counter-intuitive• A single VAV Box can impact Whole Building• Complex problems can be broken down to basics• Stress test the interactive effects of systems• If it doesn’t work on paper it will not work in reality. • HVAC Lighting nexus is only going to complicate operations further

Key Points

21

Sanjiv “Sunny” Devnanidevnani@kW-engineering.com801.599.2388

Sarah Bollsboll@Utah.gov801.538.3017

mailto:devnani@kW-engineering.commailto:sboll@Utah.gov

Death Spiral of a Building�Case Study of the Natural History Museum Bldg. Slide Number 2Slide Number 3NHMUNHMU LayoutSimplified LayoutBuilding Pressurization BasicsSlide Number 8Issues Plaguing Building OperationSlide Number 10Slide Number 11Simultaneous Dehumidification and HumidificationNHMU Air BalanceOA Dampers ClosedSlide Number 15Death Spiral of a BuildingChange in Building Pressure – Immediate ResultsSlide Number 18AHU Fan SpeedAnnual Electric CostsKey PointsSanjiv “Sunny” Devnani�devnani@kW-engineering.com�801.599.2388��Sarah Boll�sboll@Utah.gov�801.538.3017