buildingenergymodel.files.wordpress.com€¦ · Web viewchicago. central chilled. water systems (see) model analysis. building infiltration. kirby nelson. pe. 1/10/2015

CHICAGOCENTRAL CHILLEDWATER SYSTEMS

(SEE) MODEL ANALYSIS

BUILDING INFILTRATION

Kirby Nelson PE5/24/2023

Kirby Nelson PE Page 1

Contents:Executive Summary (a) ASHRAE Journal July 2014 (b) System Energy Equilibrium (SEE) Modeling (c) BASE BUILDING-Large office of (PNNL) studyCHAPTER 1: Building infiltration at peak design conditions.CHAPTER 2: Building exfiltration at peak design conditionsCHAPTER 3: Building pressure control at peak day conditions CHAPTER 4: Building pressure control at average summer conditions NOMENCLATURE:

EXECUTIVE SUMMARY(a) ASHRAE JOURNAL of July 2014In the July 2014 ASHRAE Journal under letters; Pete Menconi P.E. makes the point; “I used my first building simulation in 1973, and have used a variety of methods and on-site comparisons. In general, I’ve found typical +/- 50% variance between simulation and actual energy.”Peter Rumsey P.E. responds; “In my experience I have found the same thing.” “My experience after having modeled and measured dozens of buildings is that models do not accurately capture system performance.”I was modeling buildings of Texas Instruments Inc. in 1974 using DOE and ECUBE. These two programs could rack up the total electrical use for a year if you input the schedule, and could also do a fair job at simulating the loads due to weather. However the models could not accurately simulate the air side system or the plant performance. Sure the models had inputs for the air side and plant but system models they were not.In the late 1970’s some of us made the argument for ASHRAE models based on the equations of thermodynamics, but the decision was made to stick with the DOE approach and that is where we are today. DOE is the basis of eQUEST and Energy Pro as stated by Rumsey. The reason these DOE based models have not, cannot, and will not in the future model building energy is given on page 70 of the July 2014 ASHRAE Journal. The article (Improving Infiltration in Energy Modeling) makes the obvious but not stated point; 40 years after the oil embargo and an air side model is still not in the ASHRAE and Pacific Northwest National Labratory (PNNL) accepted energy models. The article also clearly illustrates why; empirical equations with several coefficients that have no relation to the laws of thermodynamics can never accurately model a real system. A real system operates according to the laws of thermodynamics and therefore so must our models. The hypothesis of energy conservation (first law) was established by J.P. Joule in the 1840’s. For the past 170 years the first law has provided easy to understand relations that define the performance of thermo systems. Is it not time for all to admit we have been on the wrong modeling path for more than 40 years?Kirby Nelson P.E.ASHRAE life member


(b) System Energy Equilibrium (SEE) ModelingFollowing is a brief summary of the characteristics of system energy equilibrium (SEE) models and the (SEE) model experience of the author.(SEE) ModelSystem energy equilibrium (SEE) models and schematics can be developed for any condition of weather and operational conditions that may occur in a real system. The requirement for the (SEE) model/schematic is always the same; it must duplicate the performance of the equipment that make up the system and it must obey the laws of thermodynamics and physics and include the nonlinear characteristics of the components of the system. The (SEE) model/schematics defined here assume all chillers are of the same size and model and the air handlers are the same size and model and equally loaded.Math models that duplicate the real time performance of systems are standard practice in the space program and in the development of military products such as missiles, cannons, and other complex systems. The System Energy Equilibrium (SEE) Model presented here duplicates the thermodynamic and nonlinear performance of real systems and therefore can define the best possible performance of a system consistent with the design and control concepts incorporated in the design i.e. the theoretical performance of the system.The author has found that the design and control concepts advocated by ASHRAE and Pacific Northwest National Laboratory (PNNL) yields a design that requires more demand kW and therefore energy than does a more conventional design and control strategy. These differences in design and control are detailed in other papers on this site.

Kirby Nelson experienceSystem Energy Equilibrium (SEE) modeling is not a new concept. The author was involved in this approach to modeling in the 1970’s designing military products and then as corporate energy manager for Texas Instruments Inc. modeling building systems.The concept is to simply write the basic physics and thermodynamic equations of the system and simultaneously solve the set of equations with a computer. The results will duplicate the performance of the real system if the equations are correct; nonlinear characteristics input and equipment efficiencies input. The equations can be, and should be, corrected by iterating between the real performance data verses the model and updating the model equations.

The first HVAC paper published by Kirby using this approach was in the ASHRAE Journal of December 2006. "7 Upgrades to Reduce Building Electrical Demand"In March 2010 he had an article in Engineered Systems "Central Chilled Water System Modeling" & July 2010 an HPAC article on chiller selection "Central-Chiller Plant Modeling"In 2011 a 5 article series in HPAC dealing with Primary/Secondary vs. Primary-Only Pumping. The second article dealt with the efficient control of a P/S plant and the third article with efficient control of a P-only plant. The fourth article was "Anatomy of Load delta-T" and the fifth added the building and air side equipment to the analysis.In 2012 Kirby presented two advance technical papers at ASHRAE Chicago 2012. (CH-12-002) title “Simulation Modeling of a Central Chiller Plant”


and (CH-12-003) "Simulation Modeling of Central Chilled Water Systems".Since Chicago he has continued to develop the concept of (SEE) modeling and has entered into discussions on ASHRAExCHANGE on the ASHRAE web site. Kirby’s analysis of these issues and others to follow can be viewed at http://kirbynelsonpe.com/

Personal note:I first became involved in this approach to system analysis/design in the late 1960's and early 1970's in the design of military products, Shrike Missile, Lacer Guided Bombs, Anti-Tank Projectiles, a helicopter mounted cannon to shoot electronic sensors, and other systems including dynamics of impact with soil, as an engineer with Texas Instruments Inc. (TI). An analog/digital computer was the key to the success of the models. I became Corporate Energy Manager for (TI) in 1974 and continued to use this approach to define energy saving projects for over 30 million square feet of (TI) facilities. I also used the Control Data program ECUBE and DOE. I lost access to the analog/digital computer in 1982 when I left (TI) and only recently returned to an effort to model central chilled water systems using Excel; the only tool I have that can solve a set of simultaneous equations. My objective was and is to demonstrate the concept of (SEE) Modeling & (SEE) Schematics to the HVAC community believing the approach is a powerful and needed tool in the quest to improve the energy efficiency of buildings.Critical review is solicited.Best Regards, Kirby Nelson PE [email protected] Member ASHRAE

(c) Base BuildingThe Chicago Large Office as defined by Pacific Northwest National Laboratory (PNNL) in their study of ASHRAE STD 90.1-2010 is chosen as the benchmark building for the (SEE) modeling analysis.The study by Pacific Northwest National Laboratory (PNNL) of ASHRAE Standard 90.1-2010 defines a large office building that is used as the base building for this study. The (PNNL) study defines the building characteristics, schedules, control, and HVAC equipment of the large office building defined here as the “ASHRAE Design”. Further the ASHRAE Journal of July 2011 defines “Optimizing Design & Control of Chilled Water Plants”, which is used to define the plant of the “ASHRAE Design”. This (SEE) modeling analysis has found that the “ASHRAE Design” calls for design and control concepts that significantly increase the energy consumption of the system compared to a “(min kW) Design”. The “(min kW) Design” is, I believe, less first cost. The (PNNL) study can be viewed at;http://www.energycodes.gov/sites/default/files/documents/BECP_Energy_Cost_Savings_STD2010_May2011_v00.pdf orhttp://www.energycodes.gov/achieving-30-goal-energy-and-cost-savings-analysis-ashrae-standard-901-2010

The (PNNL) study defines the building as given by Figure, a 13 story office with 498,600 square feet of air conditioned space.


http://www.energycodes.gov/achieving-30-goal-energy-and-cost-savings-analysis-ashrae-standard-901-2010



mailto:[email protected]

FIGURE: Building description

CHAPTER 1: Building infiltration vs. zero infiltration at peak design conditions.

76.0 75.073.0

76.078.0 79.0 80.0 81.0 81.8

80.0 79.0 78.0

80.0

77.0 77.079.0

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88.090.0

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ture

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)

TIME OF DAY

Peak Design Day Weather

(Temp)wet bulb (Temp)dry bulb

FIGURE 1-1: Peak Day WeatherFigure 1-1 gives the peak design weather at 4:00PM and assumes the other conditions for a peak design day.

356 346 343 387

1,155

1,692 1,731 1,7921,866

1,159

764

469368 351 346 401

1,185

1,736 1,7791,851

1,935

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DRY BULB TEMPERATURE (F)

Syst

em (k

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Syst

em (k

W)

TIME of DAY

SYSTEM TOTAL (kW)

Zero building infiltration (CFM) Building infiltration (.2016 CFM/wall sq-ft)

FIGURE 1-2: Total system kWFigure 1-2 gives the 24 hour system kW for .2016 CFM of infiltration per wall square foot and zero infiltration. Infiltration increases the load and therefore the system kW at peak design; why is addressed below.

731 731

425506

535628

356 346 343 387

1,155

1,692 1,7311,792 1,866

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Dry bulb (F)

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TIME OF DAY

SYSTEM kW -All electric 498,600 sqft Bld. -zero building infiltration

(Bld)kW (AHU)Fan kW (plant)kW (System)kW Duct heat kW FA Heat kW

FIGURE 1-3: System kW by componentFigure 1-3 gives the 24 hour kW demand of the major components of the system with zero infiltration. Figure 1-4 gives the kW demand of the components with infiltration as defined above. Building kW is the same for both conditions of infiltration. The plant kW and air handler kW is greater for the condition of infiltration because the


building cooling load is greater as shown by Figure 1-5.

438530

567673

731 731

368 351 346 401

1,185

1,736 1,779 1,8511,935

1,193

796

489

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DRY BULB (F)

(kW

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kW

TIME OF DAYSYSTEM kW-All electric-498,600 sqft .2016 CFM/sq-ft infiltration

(AHU)Fan kW (plant)kW (Bld)kW (System)kW Duct heat kW FA Heat kW

FIGURE 1-4: System kW by component with infiltration

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

37.9 37.031.8

38.542.1 43.1 44.0 45.7 46.9

44.7 43.7 42.1

4.9 3.1 3.1 4.3 6.1 8.0 9.8 11.0 12.19.2 7.4 6.1

-20-15-10-505101520253035404550

-20-15-10

-505

101520253035404550

WET BULB (F)

TON

TON

DRY BULB (F)

Building infiltration and zero exfiltration loads (ton)

Exfil Lat Ton Exfil Sen Ton Infil Lat Ton Infill Sen Ton

FIGURE 1-5: Building filtration loads (ton)Figure 1-5 illustrates the building perimeter loads due to infiltration. At peak design the sensible load is 12.1 ton and the latent load is 46.9 ton. Zero infiltration results in zero perimeter load.

3120 20

45

104

141 147 151161

138

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41

3623 23

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149157 162

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BUILDING PERIMETER LOADS-(ASHRAE) Design-Wk day

Total Bld Sen-ton with zero infiltration Exfiltration Lat-TonTotal BLD Sen-Ton with infiltration Infiltration Lat. TonInfiltration Sen-Ton Exfiltration Sen-Ton

FIGURE 1-6: Building perimeter loadsFigure 1-6 illustrates the perimeter loads due to infiltration and zero infiltration. The total sensible load is shown for both conditions of infiltration; showing the approximate 12 ton increase in sensible load due to infiltration. The latent load is, as shown by Figures 1-5 and 1-6, delivered to the air handler coils as will be shown below by Figure 1-7.


BLD ft2 = 498600 %clear sky = 100.0% InfilLat-ton = 46.94# floors = 13 Tdry-bulb = 91.7 Infil-CFM = 6811 <<<Roof ft2 = 38,354 Twet-bulb= 81.8 Infilsen-ton = 12.1

N/S wall ft2 = 40,560 WallNtrans ton= 3.95E/W wall ft2 = 27,008 WallStrans ton= 4.38

Wall % glass= 37.5% WallEtrans ton= 3.44Glass U = 0.55 WallWtranston= 2.63 WallTot trans ton = 14.4

Wall U = 0.09 GlassN trans ton = 13.73Glass SHGC = 0.40 GlassS trans ton = 13.73

Wall emitt = 0.55 GlassE-trans ton = 9.14RoofTrans ton = 31.9 GlassW-trans ton = 9.14 GlassTot-trans-ton= 45.8Roofsky lite ton = 0.0 GlassN-solar-ton = 7.1

Peopleton = 60 kW GlassS-solar-ton = 22.3plugton = 93 328 GlassE-solar ton = 4.7Lightton= 115 404 GlassW-solar ton = 33.1 GlassTot-solar-ton = 67.2

(int-cfm)to-per-ret= 185495 BLD kW= 731.4 (int cfm)per-ton = 33.39 >Total Bldint-ton = 299.5 AHU kW= 530.5 Tot Bldper-sen-ton = 172.8 v

Tstat-int= 74.0 SITE kW = 1261.9 Tstat-per = 72.0 return(Bld)int.air-ton= -299.5 ^ Design 4PM ^ (Bld)per.air-ton= -172.8 air

Tair supply int= 56.06 ASHRAE Design Tair supply per= 56.58 ^ ABS Bld Ton = 472.30 ^

Ton kW Ton kW V(fan)int-ter= 17.7 62.4 (fan)per-ter= 17.7 62.4

Theat-air= 55.0 (D)heat = 0.0 0.0

Treheat air = 55.0(D)reheat = 0.0 0.0

62.4(D)int-air-ton= -317.2 Interior (D)per-air-ton= -213.0 Peri

Tair coils = 55.00 duct Tair coils= 55.00 duct(D)int-CFM= 185,495 ^ (D)per-CFM= 124,565 ^

>>>(Coil)sen-ton= 660 ^ (coil)gpm= 43.2 ^(coil)cap-ton= 33.6 UAdesign= 2.66

(coil)H2O-ft/sec= 1.19 COIL UA= 2.64(coil)des-ft/sec= 1.20 (one coil)ton= 35.53

LMTD= 12.72 (H)coil= 2.1 V(COIL)L+s-ton= 924 ^ ^ ^ (H)coil-des= 2.1

<<<< Tair VAV= 78.64 TBLD-AR = 72.00(FAN)VAV-CFM= 310,060 (Air)ret-CFM = 316,870 Return(FAN)ton-VAV= 88.7 (FAN)ret-kW= 94 Fan(FAN)kW-VAV= 312 (FAN)ret-ton= 26.6 V

^ (Air)ret-ton = 511.426 F.A.Inlet ^ Tar-to-VAV = 72.93

statFA= 42 26 VAV FANS VAVret-ton = 432.9 TFA to VAV = 91.7 > Tret+FA = 75.46 InfilVAV-Lat-ton = 39.73

>(FA)sen-ton = > 138.1 (dh) = 5.645 < VAVret-CFM = 268,242 <> (FA)CFM= 41,817 > Efan-VSD= 0.659 InfilCFM-ton = 11.0 V

> (FA)Lat-ton= 224.2(FA)kW= 0.0 ExLat-ton = -7.2

ExCFM = -48,628

temp pink TEx = 72.93gpm orange Exsen-ton = -78.5 V kW red

FIGURE 1-7: Air side with infiltrationComparing Figures 1-7 & 1-8 gives understanding of the effect of infiltration on the air side system at peak design 4:00PM. As discussed above the building sensible load is about 12 ton greater with infiltration. The fresh air into the building is the same for both conditions; so the exhaust is greater by the infiltration amount as shown by comparing the two Figures 1-7 & 1-8.Figure 1-7 illustrates the infiltration latent load is partially exhausted but most is delivered to the coil.

BLD ft2 = 498600 %clear sky = 100.0% InfilLat-ton = 0.00# floors = 13 Tdry-bulb = 91.7 exfil-CFM = 0 >>Roof ft2 = 38,354 Twet-bulb= 81.8 Infilsen-ton = 0.0






(int-cfm)to-per-ret= 185495 BLD kW= 731 (int cfm)per-ton = 33.39 >Tot Bldint-ton = 299.5 AHU kW= 506 Tot Bldper-sen-ton = 160.8 v

Tstat-int= 74.0 SITE kW = 1237.9 Tstat-per = 72.0 return(Bld)int.air-ton= -299.5 ^ Design 4PM ^ (Bld)per.air-ton= -160.8 air



Theat-air= 55.0 (D)heat = 0.0 0.0











> (FA)Lat-ton= 224.2(FA)kW= 0.0 ExLat-ton = 0.0

ExCFM = -41,817


FIGURE 1-8: Air side with zero infiltration

Fan CFM is greater and therefore the fan kW is greater for infiltration as shown by Figure 1-7. The net result is a greater load of about 58 ton delivered to the plant by the coils for the system of Figure 1-7.The total system is given next.


BLD ft2 = 498600 %clear sky = 100.0% InfilLat-ton = 46.94Condenser # floors = 13 Tdry-bulb = 91.7 Infil-CFM = 6811 <<<

(cond)ton= 553 Pipesize-in =6" (H)T-pipe= 13.5 Tower Roof ft2 = 38,354 Twet-bulb= 81.8 Infilsen-ton = 12.1TCR= 105.2 > gpmT= 1800 > (ewt)T= 104 tfan-kW= 8.3 N/S wall ft2 = 40,560 WallNtrans ton= 3.95

TCR-app= 1.32 (H)T-total= 74.7 (H)T-static = 9.9 Tfan-kW= 16.6 E/W wall ft2 = 27,008 WallStrans ton= 4.38(COND)ton= 1106 PT-heat = -1.47 Trange= 14.7 tfan-%= 100% Wall % glass= 37.5% WallEtrans ton= 3.44

(H)cond= 51.3 < pT-kW= 30.5 < (lwt)T = 89.1 tton-ex= -555 Glass U = 0.55 WallWtranston= 2.63 WallTot trans ton = 14.4(cond)ft/sec= 10.8 EfTpump= 0.83 Tapproach = 7.3 T#= 2 Wall U = 0.09 GlassN trans ton = 13.73

Ptower # = 2 T-Ton-ex= -1110 Glass SHGC = 0.40 GlassS trans ton = 13.73Trg+app = 22.0 Wall emitt = 0.55 GlassE-trans ton = 9.14

Compressor ASHRAE Design RoofTrans ton = 31.9 GlassW-trans ton = 9.14 GlassTot-trans-ton= 45.8(chiller)kW= 285 Chicago 90.1-2010 Roofsky lite ton = 0.0 GlassN-solar-ton = 7.1(chiller)lift= 62.4 Large Office Peopleton = 60 kW GlassS-solar-ton = 22.3(chiller)%= 100% Peak day Design 4PM plugton = 93 328 GlassE-solar ton = 4.7(chiller)#= 2 Weather %clear sky = 1.00 Lightton= 115 404 GlassW-solar ton = 33.1 GlassTot-solar-ton = 67.2

(CHILLER)kW= 570 conditions Tdry bulb = 91.7 (int-cfm)to-per-ret= 185495 BLD kW= 731.4 (int cfm)per-ton = 33.39 >(chiller)kW/ton= 0.609 Twet bulb = 81.8 Total Bldint-ton = 299.5 AHU kW= 530.5 Tot Bldper-sen-ton = 172.8 vPlant kW = 672.8 Tstat-int= 74.0 SITE kW = 1261.9 Tstat-per = 72.0 return

(Bld)int.air-ton= -299.5 ^ Design 4PM ^ (Bld)per.air-ton= -172.8 airTair supply int= 56.06 ASHRAE Design Tair supply per= 56.58

^ ABS Bld Ton = 472.30 ^ > Evaporator Ton kW Ton kW V

(evap)ton= 468.1 (fan)int-ter= 17.7 62.4 (fan)per-ter= 17.7 62.4TER= 42.7 Theat-air= 55.0

TER-app= 1.30 (D)heat = 0.0 0.0 ^ EVAPton= 936 Treheat air = 55.0

(H)evap= 51.9 (D)reheat = 0.0 0.0(evap)ft/sec= 10.44 62.4

(evap)des-ft/sec= 10.44 (D)int-air-ton= -317.2 Interior (D)per-air-ton= -213.0 Peri ^ V Tair coils = 55.00 duct Tair coils= 55.00 duct

gpmevap= 1200 Psec-heat-ton = -2.4 (D)int-CFM= 185,495 ^ (D)per-CFM= 124,565 ^(lwt)evap = 44.02 > Psec-kW= 38.8 > (ewt)coil= 44.0 >>>(Coil)sen-ton= 660 ^ (coil)gpm= 43.2 ^

(H)pri-total= 61.4 v Efdes-sec-p = 0.80 (coil)cap-ton= 33.6 UAdesign= 2.66 ^ (H)pri-pipe= 2.5 Tbp= 44.02 Efsec-pump = 0.78 (coil)H2O-ft/sec= 1.19 COIL UA= 2.64

(H)pri-fitings= 7.0 gpmbp= -76 (H)sec= 143 PLANTton = 924 (coil)des-ft/sec= 1.20 (one coil)ton= 35.53(Ef)c-pump= 0.81 (H)pri-bp= 0.01 (H)sec-pipe= 81 LMTD= 12.72 (H)coil= 2.1 VPc-heat-ton= -0.93 v (H)sec-bp= 0.00 Pipesize-in = 8.0 (COIL)L+s-ton= 924 ^ ^ ^ (H)coil-des= 2.1

^ < pc-kW= 17.1 (ewt)evap = 62.74 < (gpm)sec= 1124 < (lwt)coil= 64.0 <<<< Tair VAV= 78.64 TBLD-AR = 72.00Pchiller-# = 2 (FAN)VAV-CFM= 310,060 (Air)ret-CFM = 316,870 Return

Chicago 4PM All ElectricFuel Heat (FAN)ton-VAV= 88.7 (FAN)ret-kW= 94 FanPerformance 4PM Design kW THERM (FAN)kW-VAV= 312 (FAN)ret-ton= 26.6 V

chillerkW/evapton= 0.609 BLD.kW= 731.4 ^ (Air)ret-ton = 511.4(plant)kW/site ton= 0.728 (Fan)kW = 530.5 26 F.A.Inlet ^ Tar-to-VAV = 72.93CCWSkW/bld ton= 2.55 Ductheat= 0.0 0.00 statFA= 42 26 VAV FANS VAVret-ton = 432.9WeatherEin-ton = 650.5 (FA)heat= 0.0 0 TFA to VAV = 91.7 > Tret+FA = 75.46 InfilVAV-Lat-ton = 39.73(Site)kW-Ein-ton = 358.9 Heat total = 0.0 0.00 Tdry bulb = 91.7 >(FA)sen-ton = > 138.1 (dh) = 5.645 < VAVret-CFM = 268,242 <PlantkW-Ein-ton = 191.4 PlantkW= 672.8 Fresh air > >>> > (FA)CFM= 41,817 > Efan-VSD= 0.659 InfilCFM-ton = 11.0 V

Total Ein-ton = 1201 SystkW = 1934.8 1934.8 Twet bulb = 81.8 > (FA)Lat-ton= 224.2Pumptot-heat-ton = -4.8 (FA)kW= 0.0 ExLat-ton = -7.2

AHU ExLat-ton = -7.2 BLD.kW= 731.4 SEE SCHEMATIC ExCFM = -48,628AHU Exsen-ton = -78.5 CCWSkW = 1203.3 ton blue water temp pink TEx = 72.93Tower Tton-Ex = -1110 SystkW = 1934.8 air cfm purplewater gpm orange Exsen-ton = -78.5 V Total Eout-ton = -1201 air temp green kW red

FIGURE 1-9: System with infiltrationComparing Figures 1-9 & 1-10 we get about 58 kW more system kW with infiltration at peak design conditions.The weather energy into the system with infiltration is about 69 ton more; resulting in greater site and plant energy into the system as shown by the tables in the lower left of the figures.


BLD ft2 = 498600 %clear sky = 100.0% InfilLat-ton = 0.00Condenser # floors = 13 Tdry-bulb = 91.7 exfil-CFM = 0 >>

(cond)ton= 518 Pipesize-in =6" (H)T-pipe= 13.5 Tower Roof ft2 = 38,354 Twet-bulb= 81.8 Infilsen-ton = 0.0TCR= 103.8 > gpmT= 1800 > (ewt)T= 102.5 tfan-kW= 8 N/S wall ft2 = 40,560 WallNtrans ton= 3.95

TCR-app= 1.30 (H)T-total= 74.7 (H)T-static = 9.9 Tfan-kW= 17 E/W wall ft2 = 27,008 WallStrans ton= 4.38(COND)ton= 1035 PT-heat = -1.47 Trange= 13.80 tfan-%= 100% Wall % glass= 37.5% WallEtrans ton= 3.44



Compressor ASHRAE Design RoofTrans ton = 31.9 GlassW-trans ton = 9.14 GlassTot-trans-ton= 45.8(chiller)kW= 265 Chicago 90.1-2010 Roofsky lite ton = 0.0 GlassN-solar-ton = 7.1(chiller)lift= 60.7 Large Office Peopleton = 60 kW GlassS-solar-ton = 22.3(chiller)%= 93% Peak day Design 4PM plugton = 93 328 GlassE-solar ton = 4.7(chiller)#= 2 Weather %clear sky = 100% Lightton= 115 404 GlassW-solar ton = 33.1 GlassTot-solar-ton = 67.2

(CHILLER)kW= 530 conditions Tdry bulb = 91.7 (int-cfm)to-per-ret= 185495 BLD kW= 731 (int cfm)per-ton = 33.39 >(chiller)kW/ton= 0.604 Twet bulb = 81.8 Tot Bldint-ton = 299.5 AHU kW= 506 Tot Bldper-sen-ton = 160.8 vPlant kW = 628.5 Tstat-int= 74.0 SITE kW = 1237.9 Tstat-per = 72.0 return









(H)pri-fitings= 7.0 gpmbp= -147 (H)sec= 132.7 PLANTton = 866 (coil)des-ft/sec= 1.20 (one coil)ton= 33.30(Ef)c-pump= 0.81 (H)pri-bp= 0.04 (H)sec-pipe= 71 LMTD= 12.38 (H)coil= 1.8 VPc-heat-ton= -0.93 v (H)sec-bp= 0.00 Pipesize-in = 8.0 (COIL)L+s-ton= 866 ^ ^ ^ (H)coil-des= 2.1



chillerkW/evapton= 0.604 BLD.kW= 731.4 ^ (Air)ret-ton = 487.4plantkW/site ton= 0.726 (Fan)kW = 506.5 26 F.A.Inlet ^ Tar-to-VAV = 72.92

CCWSkW/bld ton= 2.47 Ductheat= 0.0 0.00 statFA= 42 26 VAV FANS VAVret-ton = 419.9WeatherEin-ton = 581.1 (FA)heat= 0.0 0 TFA to VAV = 91.7 > Tret+FA = 75.52 InfilVAV-Lat-ton = 0.00(Site)kW-Ein-ton = 352.1 Heat total = 0.0 0.00 Tdry bulb = 91.7 >(FA)sen-ton = > 138.1 (dh) = 5.425 < VAVret-CFM = 260,350 <PlantkW-Ein-ton = 178.8 PlantkW= 628.5 Fresh air > >>> > (FA)CFM= 41,817 > Efan-VSD= 0.656 InfilCFM-ton = 0.0 V

Total Ein-ton = 1112 SystkW = 1866.4 1866.4 Twet bulb = 81.8 > (FA)Lat-ton= 224.2Pumptot-heat-ton = -4.7 (FA)kW= 0.0 ExLat-ton = 0.0

AHU ExLat-ton = 0.0 BLD.kW= 731.4 SEE SCHEMATIC ExCFM = -41,817

AHU Exsen-ton = -67.4 CCWSkW = 1135.0 ton blue water temp pink TEx = 72.92Tower Tton-Ex = -1040 SystkW = 1866.4 air cfm purplewater gpm orange Exsen-ton = -67.4 V Total Eout-ton = -1112 air temp green kW red

FIGURE 1-10: System with zero infiltrating

Next we will look at 24 hour performance.


BLD sq-ft = 498,600ALL ELECTRIC Peak day

Design 24hr BLD.24hr-kW= 10,096

(Fan)24hr-kW = 5,804(Duct)24hr-heat kW= 0

(FA)24hr-heat kW= 0Heat24hr-total kW= 0

Plant24hr-kW= 8,221SYST 24hr-kW = 24,121

(CCWS)24hr-kW= 14,025BLD.24hr-kW= 10,096

Total24hr-kW = 24,121Weather24h-Ein-ton= 6658SITE24h-kW-Ein-ton = 4522Plant24h-kW-Ein-ton = 2338Total24h-Ein-ton = 13518Pump24hr-heat-ton = -82

AHU Ex24hr-Lat-ton = 0AHU Ex24hr-sen-ton = -810

Tower24hr-ton-Ex = -12626Total E24hr-out-ton = -13518

FIGURE 1-11: zero infiltrationComparing Figures 1-11 & 1-13 illustrates the 24 hour kW demand of the zero infiltration system is about 3% less than the system with infiltration. Not a big number at peak design day conditions but as we will see in later chapters cold weather conditions will result in greater difference.

ASHRAE Design kbtu/sqft-day

ALL ELECTRIC SYSTEM W/sqft (bEQ)dayBLD.24hr-W/sq ft-

= 20.25 0.069(Fan)24hr-W/sq ft- = 11.64 0.040Plant24hr-W/sq ft-= 16.49 0.056

(Heat)24hr-W/sq ft-= 0.00 0.000Syst Total24hr-W/sq ft-= 48.38 0.165FIGURE 1-12: zero infiltrationFigures 1-12 & 1-14 illustrate a concept the author believes is very important to understanding and reducing the energy consumption of buildings. A (SEE) model can determine the real time theoretical energy use of a building; compared to the real time actual use one can have an on-site understanding of system inefficiencies. Comparing the model kW demand for a given hour against the kW demand that is occurring is of value.








AHU Ex24hr-Lat-ton = -150AHU Ex24hr-sen-ton = -1070


FIGURE 1-13: with infiltrationComparing Figures 1-11 & 1-13 energy in and out illustrates about 11% more energy for the system with infiltration.




(Heat)24hr-W/sq ft-= 0.00 0.000Syst Total24hr-W/sq ft-= 49.86 0.170FIGURE1-14: with infiltrationThe 24 hour (bEQ) of the model verses the actual value provides understanding not given by an annual (bEQ).NEXT CHAPTERThe next chapter will address the effect of exfiltration.


CHAPTER 2: Building exfiltration vs. infiltration at peak design conditions.

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FIGURE 2-1: Peak Day WeatherFigure 2-1 gives the peak design hour weather at 4:00PM and assumes the other conditions for an assumed peak design day.

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Exfiltration (-.2016 cfm/wall sq-ft)(kW) Infiltration (.2016 cfm/wall ft-sq) (kW)

FIGURE 2-2: Total system kWFigure 2-2 gives the 24 hour system kW for (.2016 CFM/wall sq-ft) of infiltration per wall square foot and (-.2016 of exfiltration). Exfiltration decreases the load and therefore the system kW at peak design day conditions, about 100 kW at 4PM; why is addressed below.

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SYSTEM kW -All electric 498,600 sqft Bld. -zero building infiltration


FIGURE 2-3: System kW by component-for zero infiltrationFigure 2-3 gives the 24 hour kW demand of the major components of the system with zero infiltration and Figure 2-4 illustrates that exfiltration results in a reduction in kW demand for the fan system and plant for a net decrease in system kW. Comparing Figures 2-3 & 2-4 illustrates that exfiltration reduces system kW demand.

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SYSTEM kW -All electric 498,600 sqft Bld. with exfiltration


Figure 2-4: System kW by component-with (-.2016 cfm/wall sq-ft) exfiltration

Figure 2-5 gives the kW demand of the components with infiltration. Building kW is the same for all conditions of infiltration & exfiltration. The plant kW and air handler kW is greater for the condition of infiltration because the building cooling load is greater as shown by Figures 2-6 & 2-7.


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FIGURE 2-5: System kW by component with infiltration of (.2016 cfm/wall sq-ft)

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

37.9 37.031.8

38.542.1 43.1 44.0 45.7 46.9

44.7 43.7 42.1

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Building infiltration and zero exfiltration loads (ton)


FIGURE 2-6: Building perimeter loads (ton) with infiltration & zero infiltrationFigure 2-6 illustrates the building perimeter loads due to infiltration and zero infiltration. At peak design the sensible load is 12.1 ton and the latent load is 46.9 ton. Zero infiltration results in zero perimeter loads.Figure 2-7 illustrates the perimeter cooling loads with exfiltration.

-4.90 -3.06 -3.06 -4.29 -6.13 -7.97 -9.81 -11.03 -12.08-9.19 -7.36 -6.13

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DRY BULB (F)Cooling loads due to infiltration & exfiltration


FIGURE 2-7: Perimeter cooling loads (ton) due to infiltration & exfiltrationExfiltration exhausts sensible load and latent load exhausted is zero.

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BUILDING PERIMETER LOADS-with infiltration

Wall Trans-Ton Infiltration Lat. Ton Infiltration Sen-TonGlass Trans-Ton Glass solar Ton Total BLD Perimeter Sen-Ton(int cfm)per-ton

FIGURE 2-8: Building perimeter loads with infiltrationFigure 2-8 illustrates all perimeter loads with infiltration occurring. The total perimeter load and component loads is shown. The latent load is delivered to the air handler coils as will be shown below by Figure 2-10.Figure 2-9 illustrates all perimeter loads with exfiltration occurring. With exfiltration sensible load is exhausted from the system; making a significant difference in the perimeter loads for the two conditions.


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Wall Trans-Ton exfiltration Lat. Ton exfiltration Sen-TonGlass Trans-Ton Glass solar Ton Total BLD Perimeter Sen-Ton(int-cfm)per-ton

FIGURE 2-9: Building perimeter loads with exfiltration

Next we will look at the two air side system schematics at 10AM.


BLD ft2 = 498600 %clear sky = 100.0% InfilLat-ton = 43.06# floors = 13 Tdry-bulb = 85.0 infil-CFM = 6811 <<Roof ft2 = 38,354 Twet-bulb= 79.0 Infilsen-ton = 8.0







Tstat-int= 74.0 SITE kW = 1169.1 Tstat-per = 72.0 return(Bld)int.air-ton= -269.2 ^ Design 10AM ^ (Bld)per.air-ton= -149.2 air



Theat-air= 55.0 (D)heat = 0.0 0.0












ExCFM = -48,628


FIGURE 2-10: Air side with infiltrationComparing Figures 2-10 & 2-11 provides understanding of the effect of infiltration on the air side system at 10:00AM. The building sensible load is about 8 ton greater with infiltration and minus 8 ton with exfiltration for a net effect of 16 ton. The fresh air into the building is the same for both conditions; so the exhaust is greater by the infiltration amount as shown by comparing the two Figures 2-10 & 2-11. Figure 2-10 illustrates the infiltration latent load is partially exhausted but most is delivered to the coil.

BLD ft2 = 498600 %clear sky = 100.0% InfilLat-ton = 0.00# floors = 13 Tdry-bulb = 85.0 exfil-CFM = -6811 >>Roof ft2 = 38,354 Twet-bulb= 79.0 Infilsen-ton = -8.0










Theat-air= 55.0 (D)heat = 0.0 0.0










>(FA)sen-ton = > 112.9 (dh) = 4.529 < VAVret-CFM = 224,724 <> (FA)CFM= 41,817 > Efan-VSD= 0.642 InfilCFM-ton = -10.9 V


ExCFM = -35,006


FIGURE 2-11: Air side with exfiltrationFan CFM is greater and therefore the fan kW is greater for infiltration as shown by Figure 2-10. The net result is a greater load of about 58 ton delivered to the plant by the coils for the system of Figure 2-10.The total system at peak design hour is given next.























FIGURE 2-11: System with infiltrationComparing Figures 2-11 & 2-12 we get about 105 kW more system kW with infiltration at 4PM peak design conditions.The weather energy into the system with infiltration is about 92 ton more; resulting in

greater site and plant energy into the system as shown by the tables in the lower left of the figures.


BLD ft2 = 498600 %clear sky = 100.0% InfilLat-ton = 0.00Condenser # floors = 13 Tdry-bulb = 91.7 exfil-CFM = -6811 >>

(cond)ton= 507 Pipesize-in =6" (H)T-pipe= 13.5 Tower Roof ft2 = 38,354 Twet-bulb= 81.8 Infilsen-ton = -12.1TCR= 103.4 > gpmT= 1800 > (ewt)T= 102.1 tfan-kW= 8 N/S wall ft2 = 40,560 WallNtrans ton= 3.95


















CCWSkW/bld ton= 2.45 Ductheat= 0.0 0.00 statFA= 42 26 VAV FANS VAVret-ton = 406.9WeatherEin-ton = 558.6 (FA)heat= 0.0 0 TFA to VAV = 91.7 > Tret+FA = 75.58 InfilVAV-Lat-ton = 0.00(Site)kW-Ein-ton = 345.6 Heat total = 0.0 0.00 Tdry bulb = 91.7 >(FA)sen-ton = > 138.1 (dh) = 5.213 < VAVret-CFM = 252,457 <PlantkW-Ein-ton = 175.1 PlantkW= 615.8 Fresh air > >>> > (FA)CFM= 41,817 > Efan-VSD= 0.653 InfilCFM-ton = -11.0 V




FIGURE 2-12: System with exfiltration

Next we will look at 24 hour performance.











FIGURE 2-13: exfiltrationComparing Figures 2-13 & 2-15 illustrates the 24 hour kW demand of the exfiltration system is about 4.3% less than the system with infiltration. Not a big number at peak design day conditions but as we will see in later chapters cold weather conditions will result in greater difference.




(Heat)24hr-W/sq ft-= 0.00 0.000Syst Total24hr-W/sq ft-= 47.72 0.163FIGURE 2-14: exfiltrationFigures 2-14 & 2-16 illustrate a concept the author believes is very important to understanding and reducing the energy consumption of buildings. A system energy equilibrium (SEE) model can determine the real time theoretical or as designed energy use of a building. Compare to the real time actual energy use and one can have an on-site understanding of system inefficiencies. Comparing the model kW as designed kW demand for a given

hour against the actual kW demand would permit on site investigation into why the system was not performing as designed.










FIGURE 2-15: with infiltration




(Heat)24hr-W/sq ft-= 0.00 0.000Syst Total24hr-W/sq ft-= 49.86 0.170FIGURE 2-16: with infiltrationThe 24 hour (bEQ) of the model verses the actual value provides understanding not given by an annual (bEQ).NEXT CHAPTERThe next chapter will address how to control a building to achieve exfiltration. What do you believe should be controlled?


CHAPTER 3: Building Pressure Control-Controlling building exfiltration at peak design conditions.I believe return air fans cause building outside air infiltration by creating negative pressure at places in the building. A fan system with only supply fans can create positive building pressure if the exhaust dampers are controlled by a building differential pressure sensor. We will assume that control here and investigate the energy use results.

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FIGURE 3-1: Peak Day WeatherFigure 3-1 gives the peak design hour weather at 4:00PM and assumes the other conditions for an assumed peak design day.

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FIGURE 3-2: Total system kW-with return fansFigure 3-2 gives the 24 hour system kW for (.2016 CFM/wall sq-ft) of infiltration and (-.2016 of exfiltration) both curves with return fans. Exfiltration decreases the load and therefore the system kW at peak design day conditions, about 100 kW at 4PM; why is addressed below.

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FIGURE 3-3: System kW-no return fans for exfiltrationFigure 3-3 illustrates, compared to Figure 3-2, that exfiltration with no return fans results in an additional reduction of about 96 kW of system demand at 4PM.

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fans


Figure 3-4: System kW by component-with (-.2016 cfm/wall sq-ft) exfiltration-with no return fans Figure 3-4 gives component kW demand for exfiltration & no return fans & Figure 3-5 gives the kW demand of the components with infiltration & with return fans. Building kW is the same for all conditions of infiltration & exfiltration. The plant kW and air handler kW is greater for the condition of infiltration because the building cooling load is greater as shown by Figure 3-6. & the air handler kW is also reduced due to no return fans for the exfiltration system. The building loads are the same as for Chapter 2; eliminating the return fans does not change the building loads.


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Figure 3-6 illustrates the building perimeter loads due to infiltration and exfiltration. At peak design the sensible load is 12.1 ton and the latent load is 46.9 ton for the infiltration condition and minus 12.1 ton for the exfiltration condition.

-4.90 -3.06 -3.06 -4.29 -6.13 -7.97 -9.81 -11.03 -12.08-9.19 -7.36 -6.13

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FIGURE 3-6: Perimeter cooling loads (ton) due to infiltration & exfiltration

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FIGURE 3-7: Building perimeter loads with infiltrationThe perimeter loads do not change from Chapter 2 but are shown here for clarity. Figure 3-7 illustrates all perimeter loads with infiltration occurring. The total perimeter load and component loads is shown. The latent load is delivered to the air handler coils as will be shown below by Figure 3-9.Figure 3-8 illustrates all perimeter loads with exfiltration occurring. With exfiltration sensible load is exhausted from the building; making a significant difference in the perimeter loads for the two conditions.

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FIGURE 3-8: Building perimeter loads with exfiltrationNext we will look at the two air side system schematics at 10AM.












Theat-air= 55.0 (D)heat = 0.0 0.0












ExCFM = -48,628


FIGURE 3-9: Air side with infiltration & return fansComparing Figures 3-9 & 3-10 provides understanding of the effect of infiltration on the air side system at 10:00AM. The building sensible load is about 8 ton greater with infiltration and minus 8 ton with exfiltration for a net effect of about 16 ton. The fresh air into the building is, (41,817 CFM) the same for both conditions; so the exhaust is greater by the infiltration amount as shown by comparing the two Figures 3-9 & 3-10. Figure 3-9 illustrates the infiltration latent load is partially exhausted but most is delivered to the coil.











Theat-air= 55.0 (D)heat = 0.0 0.0












ExCFM = -35,006


FIGURE 3-10: Air side with exfiltration & return fansFan CFM is greater and therefore the fan kW is greater for infiltration as shown by Figure 3-9. The net result is a greater load of about 58 ton delivered to the plant by the coils for the system of Figure 3-9.The next two figures show the effect of no return fans for the exfiltration condition or positive building pressure control.












Theat-air= 55.0 (D)heat = 0.0 0.0












ExCFM = -35,006


FIGURE 3-11 copy Figure 3-10; exfiltration with return fansComparing Figures 3-11 & 3-12 illustrates that the building load is the same with and without the return fans. The return fans add load to the return air as shown by Figure 3-11, about 16 ton. Site kW is reduced by the 66 kW return fans.The increased plant load of Figure 3-11 results in a slightly greater plant kW as shown below by full system Figures 3-13 & 3-14.











Theat-air= 55.0 (D)heat = 0.0 0.0












ExCFM = -35,006


FIGURE 3-12: Remove return fans from figure 3-11

All charts and schematics are consistent with energy equilibrium, laws of thermodynamics, and manufactures performance data. This is a necessary and first test for any building energy model. To my knowledge none of the ASHRAE and (PNNL) accepted building energy models meet this test.Full schematics next.























FIGURE 3-13: System with infiltration & return fans at peak load at 4PM.This figure and the next two figures are of the system at peak design hour, 4PM. Comparing Figures 3-13 & 3-14 we get about 105 kW more system kW with infiltration at 4PM peak design conditions verses exfiltration with return fans installed.

The weather energy into the system with infiltration is about 92 ton more; resulting in greater site and plant energy into the system as shown by the tables in the lower left of Figures 3-13 & 3-14.Figure 3-15 removes the return fans from Figure 3-14.

























FIGURE 3-14: System with exfiltration & return fansControlling the exhaust dampers to achieve positive building pressure would be a difficult task with return fan operating. The next figure illustrates the system at peak design hour and return fans removed.
























AHU Exsen-ton = -53.6 CCWSkW = 1003.9 ton blue water temp pink TEx = 72.00Tower Tton-Ex = -994 SystkW = 1735.3 air cfm purple water gpm orange Exsen-ton = -53.6 V Total Eout-ton = -1052 air temp green kW red

FIGURE 3-15: System with exfiltration and no return fans.Removing the return fans results in an additional drop in system kW of about 96 kW. The difference in system kW from Figure 3-13 to 3-15 is about 200 kW or about 11% reduction by controlling building pressure to achieve exfiltration.The author suggests a careful study of the above three figures to gain a better understanding of how

central chilled water systems operate according to the laws of thermodynamics.Next we will consider 24 hour energy consumption.


Figure 3-16 gives the 24 hour energy consumption of the system with infiltration as defined above & Figure 3-17 illustrates the reduction with exfiltration but with the return fans installed. The 24 hour reduction with exfiltration is (24,859 – 23,792 = 1,067 kWh or about 4.2% reduction) in total system usage over the 24 hours at design day conditions. Note the building 24 hour value (10,096 kWh) is the same for both conditions. As discussed above the building load (ton) is more with infiltration which requires more fan and plant power as shown by comparing Figures 3-16 & 3-17.










FIGURE 3-16: Building Infiltration with return fans installed

Comparing the two figures energy in and out illustrates a significant increase in weather energy in for the infiltration condition; resulting in the need for more fan and plant energy.The message is clear; minimize or eliminate infiltration by achieving exfiltration.Next we will consider the effect of removing the return fans.










FIGURE 3-17: Building exfiltration with return fans installed


Figure 3-18 is a copy of Figure 3-17 so that a side by side comparison can be made. Figure 3-19 removes the return fans from the conditions of Figure 3-18, exfiltration.Removing the return fans reduces fan kW demand and also reduces the load on the fan system and therefore further reduces fan kW.Plant kW reduces little; the primary reduction in 24 hour kWh is due to the fan system.Weather energy in is the same for both figures; the 24 hour site and plant energy in and out represents the difference in the two Figures 3-18 & 3-19.










Figure 3-18: Copy figure 3-17 Building exfiltration with return fans installed










Figure 3-19: Building exfiltration with return fans removed


Figures 3-20 & 3-21 provide a side by side comparison of the two limits of our discussion of 24 hour energy use at peak design day conditions. Building pressure control provides an 8.2% reduction in 24 hour energy consumption at peak design day conditions for the large office as defined by the (PNNL) study.The conclusion is that allowing outside air infiltration verses building pressure control represents a significant opportunity to reduce energy consumption. Cold weather conditions will show a much greater opportunity to reduce energy use; to be addressed by an upcoming chapter.










FIGURE 3-20: copy figure 3-16 Building Infiltration with return fans installed










Figure 3-21: copy figure 3-19 Building Exfiltration with return fans removed


DAY (bEQ) & Real Time ModelThe purpose of a system model is to illustrate how a system should operate and second to help determine why the system is not meeting expectations. Therefore the model must be able to model the real time ideal performance of the system. A building energy model defines how the system should operate for weather conditions occurring in real time.Figure 3-22 will be used to illustrate the point. Assume the actual weather for the last 24 hours is as defined by Figure 3-1 above. The red numbers of Figure 3-22 illustrate the theoretical performance of the system and the blue numbers the actual performance. If the theoretical model predicts that the system should have a kW demand of 1,735 at 4PM for the real weather and operational conditions at 4PM; and the actual meter reading is 1,935 kW then the onsite ability to look for the difference in is obvious. A model that estimates the systems energy use the past year provides little if any understanding if you are at the site and the kW meter reads 1935 kW, the outside dry bulb is 91.7F and the wet bulb is 81.8F; the question is; what should the kW meter read? The answer can be had with an (SEE) 1st law model as demonstrated here.

342 335 332 371

1,116

1,594 1,627 1,679 1,735

1,098

727

449368 351 346 401

1,185

1,736 1,7791,851

1,935

1,193

796

489

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Syst

em (k

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Syst

em (k

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FIGURE 3-22: Copy of figure 3-3

Day (bEQ) values that define efficient performance of different type building for actual weather conditions would permit the comparison of the last 24 hours of building energy use against ideal or achievable performance. Cities that have this type information available will, I believe, see investments in building energy upgrades. The day (bEQ) values will be very different as seasons change; a building that operates efficiently in the summer may be very inefficient in the winter.




(Heat)24hr-W/sq ft-= 0.00 0.000Syst Total24hr-W/sq ft-= 49.86 0.170FIGURE 3-23: Day (bEQ) for infiltration & return fans installed




(Heat)24hr-W/sq ft-= 0.00 0.000Syst Total24hr-W/sq ft-= 47.72 0.163FIGURE 3-24: Day (bEQ) for exfiltration & return fans installed

Figures 3-23 & 3-24 illustrate the concept. A system energy equilibrium (SEE) model can determine the real time theoretical or as designed energy use of a building for a given city. Compare to the real time actual energy use and one can have an on-site understanding of system inefficiencies.

NEXT CHAPTERThe next chapter considers average summer weather performance.


CHAPTER 4: Building Pressure Control-Controlling building exfiltration at average summer weather conditions.I believe return air fans cause building outside air infiltration by creating negative pressure at places in the building. A fan system with only supply fans can create positive building pressure if the exhaust dampers are controlled by building differential pressure sensors. We will assume that control here and investigate the energy use results.

69.0 68.0 67.0 66.0 65.0 65.0

68.070.0

73.0 72.0 71.0 70.0

74.072.0

70.0

67.0

71.0

76.0

79.081.0

83.081.0

78.076.0

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65

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% Clear Sky

AIR

TEM

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ture

(F)

Air T

empe

ratu

re (F

)

TIME OF DAY

Average summer weather


FIGURE 4-1: Avg. Summer Day WeatherFigure 4-1 gives assumed average summer day weather conditions.

342 335 332 371

1,116

1,594 1,627 1,679 1,735

1,098

727

449368 351 346 401

1,185

1,736 1,7791,851

1,935

1,193

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FIGURE 4-2: Copy of 3-3 above-System kW- no return fans for exfiltration at peak day conditionsFigure 4-2 gives the 24 hour system kW for (.2016 CFM/wall sq-ft) of infiltration with return fans and (-.2016 of exfiltration) & no return fans at peak day weather conditions.

Comparing Figures 4-2 & 4-3 illustrates the system kW decreased about 260 kW at average weather conditions vs. peak day weather conditions.

324 323 324 340

900

1,335 1,3931,469

1,548

985

677

414334 327 336 347

933

1,4221,506

1,5781,676

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FIGURE 4-3: System kW-no return fans for exfiltration at average summer conditions

731 731

321 372283

445324 323 324 340

900

1,335 1,3931,469 1,548

985

677

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)

TIME OF DAYSYSTEM kW -All electric 498,600 sqft Bld. with exfiltration & no return

fans


Figure 4-4: System kW by component-with (-.2016 cfm/wall sq-ft) exfiltration-with no return fans Figure 4-4 gives component kW demand for exfiltration & no return fans & Figure 4-5 gives the kW demand of the components with infiltration & with return fans. Building kW is the same for all conditions of infiltration & exfiltration. The plant kW and air handler kW is greater for the condition of infiltration because the building cooling load is greater as shown by Figure 4-6. & the air handler kW is also reduced due to no return fans for the exfiltration system.


386469304

476

731 731

334 327 336 347

933

1,4221,506 1,578

1,676

1,009

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(kW

)

kW

TIME OF DAYSYSTEM kW-All electric-498,600 sqft Bld-infiltration



Figure 4-6 illustrates the building perimeter loads due to infiltration and exfiltration, a significant reduction from peak day conditions; see Figure 3-6 of Chapter 3.

-1.23 0.00 1.23 3.060.61

-2.45 -4.29 -5.52 -6.74 -5.52 -3.68 -2.45

23.6 22.3 21.2 20.715.9

12.818.1

21.7

28.1 26.8 26.1 24.8

1.2 0.0 -1.2 -3.1-0.6

2.5 4.3 5.5 6.7 5.5 3.7 2.5

-20-15-10-505101520253035404550

-20-15-10

-505

101520253035404550

WET BULB (F)

TON

TON



FIGURE 4-6: Perimeter cooling loads (ton) due to infiltration & exfiltration

8.89

2.5 6.7

26

72.1 67.2

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-27

71

117124

130142

126

94

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(TO

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TIME OF DAY



FIGURE 4-7: Building perimeter loads with infiltrationFigure 4-7 illustrates all perimeter loads with infiltration occurring. The total perimeter load and component loads is shown. The latent load is delivered to the air handler coils as will be shown below by Figure 4-9.Figure 4-8 illustrates all perimeter loads with exfiltration occurring. With exfiltration sensible load is exhausted from the building; making a significant difference in the perimeter loads for the two conditions.

3.088.89

-2.5 -6.7

5 0 -5-12

-29

16 21 26 2114 9

72.163.7 67.2

125 0

13

72

112 116 119128

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86

2133

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(TO

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(TO

N)



FIGURE 4-8: Building perimeter loads with exfiltrationNext we will look at the two air side system schematics at 10AM.












Theat-air= 55.0 (D)heat = 0.0 0.0












ExCFM = -48,628


FIGURE 4-9: Air side with infiltration & return fansComparing Figures 4-9 & 4-10 provides understanding of the effect of infiltration on the air side system at 10:00AM. The building sensible load is about 5 ton greater with infiltration. The fresh air into the building is, (41,817 CFM) the same for both conditions; so the exhaust is greater by the infiltration amount as shown by comparing the two Figures 4-9 & 4-10. Figure 4-9 illustrates the infiltration latent load is partially exhausted but most is delivered to the coil.











Theat-air= 55.0 (D)heat = 0.0 0.0












ExCFM = -35,006


FIGURE 4-10: Air side with exfiltration & no return fansFan CFM is greater and therefore the fan kW is greater for infiltration as shown by Figure 4-9. The net result is a greater load of about (502-471=31 ton) delivered to the plant by the coils for the system of Figure 4-9.The increased plant load of Figure 4-9 results in a slightly greater plant kW as shown below by full system Figures 4-11 & 4-12.


All charts and schematics are consistent with energy equilibrium, laws of thermodynamics, and manufactures performance data. This is a necessary and first test for any building energy

model. To my knowledge none of the ASHRAE and (PNNL) accepted building energy models meet this test.





















AHU ExLat-ton = -4.6 BLD.kW= 731.4 SEE SCHEMATIC ExCFM = -48,628AHU Exsen-ton = -78.1 CCWSkW = 945.0 ton blue water temp pink TEx = 72.85Tower Tton-Ex = -841 SystkW = 1676.5 air cfm purple water gpm orange Exsen-ton = -78.1 V Total Eout-ton = -928 air temp green kW red

FIGURE 4-11: System with infiltration & return fans at peak load at 4PM.Comparing Figures 4-11 & 4-12 we get about 129 kW more system kW with infiltration at 4PM weather conditions verses exfiltration with no return fans installed.

The weather energy into the system with infiltration is about 63 ton more; resulting in greater site and plant energy into the system as


shown by the tables in the lower left of Figures 4-11 & 4-12.

Controlling the exhaust dampers to achieve positive building pressure would be a difficult task with return fan operating.























AHU Exsen-ton = -53.6 CCWSkW = 816.2 ton blue water temp pink TEx = 72.00Tower Tton-Ex = -771 SystkW = 1547.6 air cfm purple water gpm orange Exsen-ton = -53.6 V Total Eout-ton = -829 air temp green kW red

FIGURE 4-12: System with exfiltration and no return fans.


Figure 4-13 gives the 24 hour energy consumption of the system with infiltration as defined above & Figure 4-14 illustrates the reduction with exfiltration and no return fans installed. The 24 hour reduction with exfiltration is (21,267 – 19,961 = 1,306 kWh or about 6.1% reduction) in total system usage over the 24 hours. Note the building 24 hour value (10,096 kWh) is the same for both conditions. As discussed above the building load (ton) is more with infiltration which requires more fan and plant power as shown by comparing Figures 4-11 & 4-12 above.










FIGURE 4-13: Building Infiltration with return fans installed

Comparing the two figures energy in and out illustrates a significant increase in weather energy in for the infiltration condition; resulting in the need for more fan and plant energy.The message is clear; minimize or eliminate infiltration by achieving exfiltration.










FIGURE 4-14: Building exfiltration with no return fans installed


DAY (bEQ) & Real Time ModelThe purpose of a system model is to illustrate how a system should operate and second to help determine why the system is not meeting expectations. Therefore the model must be able to model the real time ideal performance of the system. A building energy model defines how the system should operate for weather conditions occurring in real time.Figure 4-15 will be used to illustrate the point. Assume the actual weather for the last 24 hours is as defined by Figure 4-1 above. The red numbers of Figure 4-15 illustrate the theoretical performance of the system and the blue numbers the actual performance. If the theoretical model predicts that the system should have a kW demand of 1,548 at 4PM for the real weather and operational conditions at 4PM; and the actual meter reading is 1,676 kW then the onsite ability to look for the difference is obvious. A model that estimates the systems energy use the past year provides little if any understanding if you are at the site and the kW meter reads 1,676 kW, the outside dry bulb is 83F and the wet bulb is 73F; the question is; what should the kW meter read? The answer can be had with an (SEE) 1st law model as demonstrated here.

324 323 324 340

900

1,335 1,3931,469

1,548

985

677

414334 327 336 347

933

1,4221,506

1,5781,676

1,009

721

440

0

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em (k

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Syst

em (k

W)



FIGURE 4-15: Copy of figure 4-3

Day (bEQ) values that define efficient performance of different type building for actual weather conditions would permit the comparison of the last 24 hours of building energy use against ideal or achievable performance. Cities that have this type

information available will, I believe, see investments in building energy upgrades. The day (bEQ) values will be very different as seasons change; a building that operates efficiently in the summer may be very inefficient in the winter.




(Heat)24hr-W/sq ft-= 0.05 0.000Syst Total24hr-W/sq ft-= 42.65 0.146FIGURE 4-16: Day (bEQ) for infiltration & return fans installed




(Heat)24hr-W/sq ft-= 0.00 0.000Syst Total24hr-W/sq ft-= 40.04 0.137FIGURE 4-17: Day (bEQ) for exfiltration & return fans removed

Figures 4-16 & 4-17 illustrate the concept. A system energy equilibrium (SEE) model can determine the real time theoretical or as designed energy use of a building for a given city. Compare to the real time actual energy use and one can have an on-site real time understanding of system inefficiencies. SUMMER (bEQ)From Figure 4-16; the summer (bEQ)=90days*.146=13.14kbtu/sqftFrom Figure 4-17; the summer (bEQ)=90*.137=12.33kbtu/sqftThese values will be added to spring/fall and winter values to arrive at an estimate of annual (bEQ).NEXT CHAPTERThe next chapter considers Spring/Fall weather performance. (To be added).


System Nomenclature Each of the more than 100 components of the system will be defined.The (PNNL) study defines the large office building as given by Figure N-1, a 13 story office with 498,600 square feet of air conditioned space.

FIGURE N-1: Building description The (PNNL) study can be viewed at;http://www.energycodes.gov/sites/default/files/documents/BECP_Energy_Cost_Savings_STD2010_May2011_v00.pdf orhttp://www.energycodes.gov/achieving-30-goal-energy-and-cost-savings-analysis-ashrae-standard-901-2010

BLD ft2 = %clear sky = InfilLat-ton =

# floors = Tdry-bulb = Infil-CFM = <Roof ft2 = Twet-bulb= Infilsen-ton =

N/S wall ft2 = WallNtrans ton=E/W wall ft2 = WallStrans ton=

Wall % glass= WallEtrans ton=Glass U = WallWtranston= WallTot trans ton =

Wall U = GlassN trans ton =Glass SHGC = GlassS trans ton =

Wall emitt = GlassE-trans ton =RoofTrans ton = GlassW-trans ton = GlassTot-trans-ton=Roofsky lite ton = GlassN-solar-ton =

Peopleton = kW GlassS-solar-ton =plugton = GlassE-solar ton =Lightton= GlassW-solar ton = GlassTot-solar-ton =

(int-cfm)to-per-ret= BLD kW= (int cfm)per-ton = >Total Bldint-ton = AHU kW= Tot Bldper-sen-ton = v

Tstat-int= SITE kW = Tstat-per = return(Bld)int.air-ton= ^ Design 4PM ^ (Bld)per.air-ton= air

BUILDING NOMENCLATURE:Building structure;

BLD ft2 = air conditioned space# Floors = number of building floorsRoof ft2 = roof square feetN/S wall ft2 =north/south wall square feetE/W wall ft2 =east/west wall square feetWall % glass = percent of each wall that is glassGlass U = glass heat transfer coefficientWall U = wall heat transfer coefficientGlass SHGC = glass solar heat gain coefficientWall emit = wall solar indexBuilding interior space;Rooftrans-ton =transmission through roof (ton)Roofsky-lite-ton =sky lite load (ton)Peopleton = cooling load due to people (ton)Plugton = cooling load due to plug kWPlugtkW = kW demand due to plug loadsLightton = cooling load due to lights (ton)LightkW = kW demand due to lights(int-cfm)to-per-return = CFM of interior supply air that returns to perimeter of buildingTotal Bldint-ton = total building interior load (ton)Tstat-int = interior stat set temperature (F)Bldint-air-ton = supply air ton to offset interior loadBuilding perimeter space;%clear sky = percent solar that hits buildingTdry bulb = outside dry bulb temperature (F)Twet bulb = outside wet bulb temperature (F)Infillat-ton = latent load due to air infiltration (ton)InfilCFM = air infiltration CFMInfilsen-ton = sensible load due to air infiltration (ton)Walln trans ton = north wall transmission (ton)Walls trans ton = south wall transmission (ton)WallE trans ton = east wall transmission (ton)Wallw trans ton = west wall transmission (ton)Walltot-trans-ton = total wall transmission (ton)GlassN-trans-ton = north wall glass transmission (ton)GlassS-trans-ton = south wall glass transmission (ton)GlassE-trans-ton = east wall glass transmission (ton)GlassW trans-ton = west wall glass transmission (ton)Glasstot-trans-ton = total transmission thru glass (ton) GlassN-solar-ton = north glass solar load (ton)GlassS-solar-ton = south glass solar load (ton)GlassE-solar-ton = east glass solar load (ton)GlassW-solar-ton = west glass solar load (ton)Glasstot-solar-ton = total glass solar load (ton)(int cfm)per-ton = effect of interior CFM to wall (ton)





Total Bldper-sen-ton total perimeter sensible load (ton)Tstat-per = perimeter stat set temperature (F)Bldper-air-ton = supply air ton to offset perimeter load

Tair supply int= ASHRAE Design Tair supply per=

^ ABS Bld Ton = ^Ton kW Ton kW V

(fan)int-ter= (fan)per-ter=Theat-air= (D)heat =

Treheat air =(D)reheat =

(D)int-air-ton= Interior (D)per-air-ton= PeriTair coils = duct Tair coils= duct

(D)int-CFM= ^ (D)per-CFM= ^>>>(Coil)sen-ton= ^ (coil)gpm= ^

(coil)cap-ton= UAdesign=(coil)H2O-ft/sec= COIL UA=(coil)des-ft/sec= (one coil)ton=

LMTD= (H)coil= V(COIL)L+s-ton= ^ ^ ^ (H)coil-des=

<<<< Tair VAV= TBLD-AR =(FAN)VAV-CFM= (Air)ret-CFM = Return(FAN)ton-VAV= (FAN)ret-kW= Fan(FAN)kW-VAV= (FAN)ret-ton= V

^ (Air)ret-ton =26 F.A.Inlet ^ Tar-to-VAV =

statFA= 26 VAV FANS VAVret-ton = TFA to VAV = > Tret+FA = InfilVAV-Lat-ton =

>(FA)sen-ton = > (dh) = < VAVret-CFM = <> (FA)CFM= > Efan-VSD= InfilCFM-ton = V

> (FA)Lat-ton=(FA)kW= ExLat-ton =

ExCFM =temp pink TEx =gpm orange Exsen-ton = V

FIGURE 2A Air handler system AIR HANDLER DUCT SYSTEM NOMENCLATURE

(Bld)int.air-ton= ^ Design 4PM ^ (Bld)per.air-ton= airTair supply int= ASHRAE Design Tair supply per=





(D)int-CFM= ^ (D)per-CFM= ^

Duct system nomenclatureTair supply int = temperature air supply to interior (F)(fan)int-ter-kW = kW demand of interior terminal fans(fan)int-ter-ton = load due to interior terminal fans kW (D)int-air-ton = cooling (ton) to interior ductTair coils = supply air temperature off coils to duct(D)int-CFM = supply air CFM to interior duct

(ABS Bld Ton) = absolute building load on (CCWS)Tair supply per = temperature air supply perimeter (F)(fan)per-ter-kW = kW demand perimeter terminal fans(fan)per-ter-ton = load due to perimeter terminal fansTheat-air = temp supply air before terminal fan heat(D)heat-kW = kW heat to perimeter supply air(D)heat-ton = (ton) heat to perimeter supply airTreheat air = temp(F) perimeter supply air after reheat (D)reheat-kW = kW reheat to perimeter supply air(D)reheat-ton = (ton) reheat to perimeter supply air(D)per-air-ton = cooling (ton) to perimeter duct Tair coils = supply air temperature off coils to duct(D)per-CFM = supply air CFM to perimeter ductCOIL NOMENCLATURE(coil)sen-ton = sensible load on all coils (ton)(coil)cap-ton = LMTD * UA = capacity (ton) one coil(coil)H2O-ft/sec = water velocity thru coil (ft/sec)(coil)design-ft/sec = coil design water velocity (ft/sec)LMTD = coil log mean temperature difference (F)(coil)L+s-ton = latent + sensible load on all coils (ton)(coil)gpm = water flow (gpm) thru one coilUAdesign = coil UA design valueUA = coil heat transfer coefficient * coil area. UA varies as a function water velocity (coil)gpm thru the coil, therefore as the (coil)gpm decreases the coil capacity decreases.




<<<< Tair VAV= TBLD-AR = Coils(one coil)ton = load (ton) on one coil(H)coil = air pressure drop thru coil (ft)(H)coil-design = design air pressure drop (ft)

(COIL)L+s-ton= ^ ^ ^ (H)coil-des=<<<< Tair VAV= TBLD-AR =

(FAN)VAV-CFM= (Air)ret-CFM = Return(FAN)ton-VAV= (FAN)ret-kW= Fan(FAN)kW-VAV= (FAN)ret-ton= V







VAV FAN SYSTEM NOMENCLATUREFresh air nomenclature:statFA = fresh air freeze stat set temperature (F)TFA to VAV = temperature of fresh air to VAV fan(FA)sen-ton = fresh air sensible load (ton)(FA)CFM = CFM fresh air to VAV fan inlet(FA)Lat-ton = fresh air latent load (ton)(FA)kW = heat kW to statFA set temperatureAir return nomenclature: TBLD-AR = return air temp (F) before return fan(Air)ret-CFM = CFM air return from building(FAN)ret-kW = return fans total kW(FAN)ret-ton = cooling load (ton) due to (FAN)ret-kW

(Air)ret-ton = return air (ton) before return fansTAR to VAV = TBLD-AR + delta T due to return fans kWVAVret-ton = return (ton) to VAV fans inletInfilVAV-Lat-ton = infiltration latent (ton) to VAV fansVAVret-CFM = return CFM to VAV fans inletInfilCFM-ton = load (ton) due to infiltration CFMExhaust air nomenclatureExLat-ton = latent load (ton) exhaustedExCFM = CFM of exhaust airTEx = temperature of exhaust air Exsen-ton = sensible load (ton) exhaustedVAV Fans nomenclatureTair-VAV = temp. air to coils after VAV fan heat(FAN)VAV-CFM = CFM air thru coils(FAN)ton-VAV = load (ton) due to VAV fan kW(FAN)kW-VAV = total VAV fan kW demandTret+FA = return and fresh air mix temperature (F)(dh) = VAV air static pressure (ft)Efan-VSD = VAV fans efficiency

AIR SIDE SYSTEM PLUS BUILDING BLD ft2 = %clear sky = InfilLat-ton =

# floors = Tdry-bulb = Infil-CFM = <Roof ft2 = Twet-bulb= Infilsen-ton =

N/S wall ft2 = WallNtrans ton=E/W wall ft2 = WallStrans ton=

Wall % glass= WallEtrans ton=Glass U = WallWtranston= WallTot trans ton =

Wall U = GlassN trans ton =Glass SHGC = GlassS trans ton =

Wall emitt = GlassE-trans ton =RoofTrans ton = GlassW-trans ton = GlassTot-trans-ton=Roofsky lite ton = GlassN-solar-ton =

Peopleton = kW GlassS-solar-ton =plugton = GlassE-solar ton =Lightton= GlassW-solar ton = GlassTot-solar-ton =

(int-cfm)to-per-ret= BLD kW= (int cfm)per-ton = >Total Bldint-ton = AHU kW= Tot Bldper-sen-ton = v

Tstat-int= SITE kW = Tstat-per = return(Bld)int.air-ton= ^ Design 4PM ^ (Bld)per.air-ton= air

Tair supply int= ASHRAE Design Tair supply per=








<<<< Tair VAV= TBLD-AR =(FAN)VAV-CFM= (Air)ret-CFM = Return(FAN)ton-VAV= (FAN)ret-kW= Fan(FAN)kW-VAV= (FAN)ret-ton= V







Condenser(cond)ton= Pipesize-in = (H)T-pipe= Tower

TCR= > gpmT= > (ewt)T= tfan-kW=TCR-app= (H)T-total= (H)T-static = Tfan-kW=

(COND)ton= PT-heat = Trange= tfan-%=(H)cond= < pT-kW= < (lwt)T = tton-ex=

(cond)ft/sec= EfTpump= Tapproach = T#=Ptower # = T-Ton-ex=

Trg+app =Compressor ASHRAE Design

(chiller)kW= Chicago 90.1-2010(chiller)lift= Large Office(chiller)%= Peak day Design 4PM(chiller)#= Weather %clear sky =

(CHILLER)kW= conditions Tdry bulb =(chiller)kW/ton= Twet bulb =Plant kW =

> Evaporator(evap)ton=

TER=TER-app=

^ EVAPton=(H)evap=

(evap)ft/sec=(evap)des-ft/sec=

^ Vgpmevap= Psec-heat-ton =

(lwt)evap = > Psec-kW= > (ewt)coil=(H)pri-total= v Efdes-sec-p =

^ (H)pri-pipe= Tbp= Efsec-pump =(H)pri-fitings= gpmbp= (H)sec= PLANTton =(Ef)c-pump= (H)pri-bp= (H)sec-pipe=Pc-heat-ton= v (H)sec-bp= Pipesize-in =

^ < pc-kW= (ewt)evap = < (gpm)sec= < (lwt)coil=Pchiller-# =

CENTRAL PLANT Nomenclature will be defined by addressing each component of the plant.Primary/secondary pumping nomenclaturegpmevap = total gpm flow thru evaporators(H)pri-total = total primary pump head (ft) = (H)pri-pipe + (H)pri-fittings + (H)pri-bp + (H)evap

(H)pri-pipe = primary pump head due to piping (ft)(H)pri-fittings = primary head due to pump & fitting (ft)(Ef)c-pump = efficiency of chiller pumpPc-heat-ton = chiller pump heat to atmosphere (ton)Pc-kW = one chiller pump kW demand (kW)Pchiller-# = number chiller pumps operating(lwt)evap = temperature water leaving evaporator (F)Tbp = temperature of water in bypass (F)gpmbp = gpm water flow in bypass(H)pri-bp = head if chiller pump flow in bypass (ft)(ewt)evap = temp water entering evaporator (F)

Psec-heat-ton = secondary pump energy not into system (ton), goes to atmospherePsec-kW = kW demand of secondary pumpsEfdes-sec-p = design efficiency of secondary pumpingEfsec-pump = efficiency of secondary pumping(H)sec = secondary pump head (ft) = (H)sec-pipe + (H)sec-

bp + (H)coil + (H)valve

(H)sec-pipe = secondary pump head due to pipe (ft)(H)sec-bp = head in bypass if gpmsec > gpmevap

gpmsec = water gpm flow in secondary loop(ewt)coil = water temperature entering coil (F)Plantton = load (ton) from air side to plantPipesize-in = secondary pipe size (inches)(lwt)coil = temperature of water leaving coil (F)Condenser nomenclature:(cond)ton = load (ton) on one condenserTCR = temperature of condenser refrigerant (F)TCR-app = refrigerant approach temperature (F)(COND)ton = total load (ton) on all condensers(H)cond = tower pump head thru condenser (ft)(cond)ft/sec = tower water flow thru condenser Compressor:(chiller)kW = each chiller kW demand(chiller)lift = (TCR – TER) = chiller lift (F)(chiller)% = percent chiller motor is loaded(chiller)# = number chillers operating(CHILLER)kW = total plant chiller kW(chiller)kW/ton = chiller kW per evaporator tonEvaporator(evap)ton = load (ton) on one evaporatorTER = evaporator refrigerant temp (F)TER-app = evaporator refrigerant approach (F)EVAPton = total evaporator loads (ton)(H)evap = pump head thru evaporator (ft)(evap)ft/sec = velocity water flow thru evaporator(evap)des-ft/sec = evaporator design flow velocityTower piping nomenclaturePipesize-in = tower pipe size (inches)gpmT = each tower water flow (gpm)(H)T-total = total tower pump head (ft)PT-heat = pump heat to atmosphere (ton)PT-kW = each tower pump kW demandEfT-pump = tower pump efficiencyPtower # = number of tower pumps(H)T-pipe = total tower pump head (ft)



Tower piping nomenclature cont.(ewt)T = tower entering water temperature (F)(H)T-static = tower height static head (ft)Trange = tower range (F)= (ewt)T – (lwt)T

(lwt)T = tower leaving water temperature (F)Tapproach = (lwt)T – (Twet-bulb)Tower nomenclature

tfan-kW = kW demand of one tower fanTfan-kW = tower fan kW of fans on

tfan-% = percent tower fan speedtton-ex = ton exhaust by one tower

T# = number of towers onTton-ex = ton exhaust by all towers onTrg+app = tower range + approach (F)SYSTEM PERFORMANCE The performance indices of the following Tables are self-explanatory. A complete schematic will be shown below.

Chicago 4PM All ElectricFuel HeatPerformance 4PM Design kW THERM

chillerkW/evapton= BLD.kW=(plant)kW/site ton= (Fan)kW =CCWSkW/bld ton= Ductheat=WeatherEin-ton = (FA)heat=(Site)kW-Ein-ton = Heat total =PlantkW-Ein-ton = PlantkW=

Total Ein-ton = SystkW =Pumptot-heat-ton =

AHU ExLat-ton = BLD.kW=AHU Exsen-ton = CCWSkW =Tower Tton-Ex = SystkW =Total Eout-ton =

Performance table at given hour

BLD sq-ft =ALL ELECTRIC Peak day

Design 24hr BLD.24hr-kW=

(Fan)24hr-kW =(Duct)24hr-heat kW=

(FA)24hr-heat kW=Heat24hr-total kW=

Plant24hr-kW=SYST 24hr-kW =

(CCWS)24hr-kW=BLD.24hr-kW=

Total24hr-kW =

24 Hour performance, all-electric

ASHRAE DesignBLD sq ft =

Fuel heat Peak dayDesign 24hr ThermBLD.24hr-kW=

(Fan)24hr-kW =(Duct)24hr-heat therm=

(FA)24hr-heat therm=Heat24hr-total therm=

Plant24hr-kW=SYST 24hr-kW =

24 Hour performance, heat with fuel

Weather24h-Ein-ton= SITE24h-kW-Ein-ton = Plant24h-kW-Ein-ton =Total24h-Ein-ton =Pump24hr-heat-ton =

AHU Ex24hr-Lat-ton =AHU Ex24hr-sen-ton =

Tower24hr-ton-Ex =Total E24hr-out-ton =

ASHRAE Design

24 Hour Energy in = Energy out



=(Fan)24hr-W/sq ft- =Plant24hr-W/sq ft-=

(Heat)24hr-W/sq ft-=Syst Total24hr-W/sq ft-=

90 day (bEQ)=FUEL HEAT SYSTEM (bEQ)day

Bld,Fan,Plant24hr-W/sq ft-= 49.70Heat24hr-btu/sq ft= 0.00

Syst Total24hr-=90 day (bEQ)=

(bEQ) estimate

Next the full system energy equilibrium (SEE) schematic.


BLD ft2 = %clear sky = InfilLat-ton =

Condenser # floors = Tdry-bulb = Infil-CFM = <(cond)ton= Pipesize-in = (H)T-pipe= Tower Roof ft2 = Twet-bulb= Infilsen-ton =

TCR= > gpmT= > (ewt)T= tfan-kW= N/S wall ft2 = WallNtrans ton=TCR-app= (H)T-total= (H)T-static = Tfan-kW= E/W wall ft2 = WallStrans ton=

(COND)ton= PT-heat = Trange= tfan-%= Wall % glass= WallEtrans ton=(H)cond= < pT-kW= < (lwt)T = tton-ex= Glass U = WallWtranston= WallTot trans ton =

(cond)ft/sec= EfTpump= Tapproach = T#= Wall U = GlassN trans ton =Ptower # = T-Ton-ex= Glass SHGC = GlassS trans ton =

Trg+app = Wall emitt = GlassE-trans ton =Compressor ASHRAE Design RoofTrans ton = GlassW-trans ton = GlassTot-trans-ton=

(chiller)kW= Chicago 90.1-2010 Roofsky lite ton = GlassN-solar-ton =(chiller)lift= Large Office Peopleton = kW GlassS-solar-ton =(chiller)%= Peak day Design 4PM plugton = GlassE-solar ton =(chiller)#= Weather %clear sky = Lightton= GlassW-solar ton = GlassTot-solar-ton =

(CHILLER)kW= conditions Tdry bulb = (int-cfm)to-per-ret= BLD kW= (int cfm)per-ton = >(chiller)kW/ton= Twet bulb = Total Bldint-ton = AHU kW= Tot Bldper-sen-ton = vPlant kW = Tstat-int= SITE kW = Tstat-per = return

(Bld)int.air-ton= ^ Design 4PM ^ (Bld)per.air-ton= airTair supply int= ASHRAE Design Tair supply per=

^ ABS Bld Ton = ^ > Evaporator Ton kW Ton kW V

(evap)ton= (fan)int-ter= (fan)per-ter=TER= Theat-air=

TER-app= (D)heat = ^ EVAPton= Treheat air =

(H)evap= (D)reheat =

(evap)ft/sec=(evap)des-ft/sec= (D)int-air-ton= Interior (D)per-air-ton= Peri

^ V Tair coils = duct Tair coils= ductgpmevap= Psec-heat-ton = (D)int-CFM= ^ (D)per-CFM= ^

(lwt)evap = > Psec-kW= > (ewt)coil= >>>(Coil)sen-ton= ^ (coil)gpm= ^(H)pri-total= v Efdes-sec-p = (coil)cap-ton= UAdesign=

^ (H)pri-pipe= Tbp= Efsec-pump = (coil)H2O-ft/sec= COIL UA=(H)pri-fitings= gpmbp= (H)sec= PLANTton = (coil)des-ft/sec= (one coil)ton=(Ef)c-pump= (H)pri-bp= (H)sec-pipe= LMTD= (H)coil= VPc-heat-ton= v (H)sec-bp= Pipesize-in = (COIL)L+s-ton= ^ ^ ^ (H)coil-des=

^ < pc-kW= (ewt)evap = < (gpm)sec= < (lwt)coil= <<<< Tair VAV= TBLD-AR =Pchiller-# = (FAN)VAV-CFM= (Air)ret-CFM = Return

Chicago 4PM All ElectricFuel Heat (FAN)ton-VAV= (FAN)ret-kW= FanPerformance 4PM Design kW THERM (FAN)kW-VAV= (FAN)ret-ton= V

chillerkW/evapton= BLD.kW= ^ (Air)ret-ton =(plant)kW/site ton= (Fan)kW = 26 F.A.Inlet ^ Tar-to-VAV =CCWSkW/bld ton= Ductheat= statFA= 26 VAV FANS VAVret-ton = WeatherEin-ton = (FA)heat= TFA to VAV = > Tret+FA = InfilVAV-Lat-ton =(Site)kW-Ein-ton = Heat total = Tdry bulb = >(FA)sen-ton = > (dh) = < VAVret-CFM = <PlantkW-Ein-ton = PlantkW= Fresh air > >>> > (FA)CFM= > Efan-VSD= InfilCFM-ton = V

Total Ein-ton = SystkW = Twet bulb = > (FA)Lat-ton=Pumptot-heat-ton = (FA)kW= ExLat-ton =

AHU ExLat-ton = BLD.kW= SEE SCHEMATIC ExCFM =AHU Exsen-ton = CCWSkW = ton blue water temp pink TEx =Tower Tton-Ex = SystkW = air cfm purplewater gpm orange Exsen-ton = V Total Eout-ton = air temp green kW red

System Energy Equilibrium (SEE) Schematic


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buildingenergymodel.files.wordpress.com€¦ · Web viewchicago. central chilled. water systems (see) model analysis. building infiltration. kirby nelson. pe. 1/10/2015