02 hap-4 4-systems-carrier

Hourly Analysis Program

Hourly Analysis Program

SYSTEMS

Systems

General

AIR SYSTEM

PROPERTIES

EquipmentTypesAir systemTypes

SYSTEMS

DirectZone

Exhaust

Active Dehumidification

Humidity

ReheatCoil

Zone

SINGLE ZONE CONSTANT VOLUME SYSTEM

CONSTANT VOLUME WITH TERMINAL REHEAT SYSTEM

VAV SYSTEM

VAV REHEAT SYSTEM

Series / Parallel Fan Powered Mixing Boxes

Zone HeatOptional

Zone HeatOptional

Zone Zone

CC

RH RH

TT

SFPMXB PFPMXB

Exhaust

OutdoorVentilation

Supply Fan

Return FanOptional

PlenumReturn

TerminalFan Terminal

Fan

Return Air

CAV - 2-Deck MULTIZONE SYSTEM

CAV - 3-Deck MULTIZONE SYSTEM

TEMPERING VENTILATION SYSTEM

SYSTEM OF TERMINAL UNITSWITH COMMON VENTILATION

TERMINAL UNIT WITH DIRECT VENTILATION

VVT SYSTEM

DUAL DUCT CONSTANT VOLUME SYSTEM

DUAL DUCT VAV SYSTEM

2-FAN DUAL DUCT VAV SYSTEM

4-PIPE INDUCTION SYSTEM

SYSTEMS

SYSTEMS AVAILABLE

Undefined

• CAV SingleZone

• CAV TerminalReheat

• VAV

• VVT

PACKAGE ROOFTOP

• CAV Single Zone

• CAV Terminal Reheat

• Multi Zone

• Bypass Multi Zone

• Dual Duct CAV

• Tempering Vent

• VAV

• 1 fan dual Duct VAV

• 2 fan Dual Duct VAV

• VVT

PACKAGE VERTICAL

• CAV SingleZone

• CAV TerminalReheat

• VAV

• VVT

SINGLE DX AHU

• CAV Single Zone

• CAV Terminal Reheat

• Multi Zone

• Bypass Multi Zone

• Dual Duct CAV

• Tempering Vent

• VAV

• 1 fan dual Duct VAV

• 2 fan Dual Duct VAV

• VVT

OUTDOOR AIR OPTIONS

There Are Three Choices for Determining the amountof Ventilation Air in CAV Systems

Constant, Scheduled, or CO2 Sensor

There Are Four Choices for Determining the L/s ofVentilation Air in VAV Systems

Constant, Proportional, Scheduled, or CO2 Sensor

Ventilation Sizing can be done based on “Sum ofSpaces OA Air flows” or “ Ashrae standard 62-2001”

O.A. for CAV Units

O.A. for VAV Units

ECONOMIZER OPERATION

ECONOMIZER OPERATION

An economizer is used to vary the flow of outdoor airinto the system

Mechanical cooling is reduced or can be eliminated

Integrated Dry bulb

• Integrates with mechanical cooling.Partial freecooling is available

Integrated Enthalpy

Non integrated dry bulb

• Does not integrate with mechanical cooling

INTEGRATED DRY BULB

Compare OA & RA. Dry Bulb

“A” OA > RA Damper closedto min.

“B” OA < RA Damper fullopen. Integration area

“C” Dampers modulate formix

“D” Dampers closed to min.Heating may be needed

D C B A

Outdoor Air Temperature

Total O.A Flow Rate

Recommended for Cool and Dry Climates

INTEGRATED ENTHALPY

Enthalpy of OA and RA compared

“A” Enthalpy OA > RA Min.Damper

“B” Enthalpy OA < RA 100% OA

‘C” Dampers modulate mix forcooling

“D” Dampers at Min.D C B A

Total O.A Flow Rate

Outdoor air State

Recommended for Cool and Humid Climates

NON-INTEGRATED DRY BULB

Compare OA/DB and coil outlet DB

“A” & “B” OA/DB> Coil outlet DB

“C” OA/DB < Coil outlet DBDampers control mix to eliminatemechanical cooling

“D” Min. Position

D C B A

Total O.A Flow Rate

Outdoor Air Temperature

Vent Reclaim

Pre cooling

SYSTEMS

SYSTEMS

COMPONENTS

Humidification

SYSTEMS

SYSTEMS

COMPONENTS

Dehumidification

SYSTEMS

SYSTEMS

COMPONENTS

Central Cooling

SYSTEMS COMPONENTS

Supply Fan

Air SystemInput

SystemComponents

Duct System

Supply DuctData

Duct Heat Gain & Leakage

Only the heat gained or lost by supply duct systemsis significant.

Estimated as a percentage of space sensible coolingload (usually about 1%)

Applied to the Coil LAT db as an equivalenttemperature reduction.

Duct Heat Gain

Air leakage out of (or into) ductwork

Has greater impact than duct heat gain or loss

Outward leakage is a direct loss of cooling and/ordehumidifying capacity

A well-designed and installed duct system leaks no more than 1 to3% of the total system airflow

Poorly designed or installed duct systems can leak 10 to 30%

Duct leakage doesn’t always affect overall system loads enoughto cause problems BUT:

Results in larger fan airflow rates at zone terminals

Latent heat considerations are frequently ignored

Duct Leakage

Supply & Return DuctLeakage Loss Supply & Return Duct

Heat Gain

Air-ConditionedSpace

Section 8 – Load Components

Duct Heat Gain & Leakage

Air SystemInput

SystemComponents

Return DuctData

Duct Heat Gain & Leakage

Top Floor

70% Roof Heat

Return Air Plenum 87° F

Air Conditioned Space 75° F

30% Light Heat (S+T)W

Section 8 – Load Components

Ceiling Return Plenum

ZONE COMPONENTS

Assignmentof Spaces

AlphaNumericSort Orderfor Spacesin ZoneSelection

ZONE COMPONENTS

Diversity Factor

To be used in zones with highlyvariable occupancy or latentload (e.g. Conference Rooms)

Zone Air Flow is calculatedbased on user’s input.

System Cooling Coil Load iscalculated after applyingdiversity factor to the internalloads.

Ex.: For a 60% diversityfactor, an occupancy load of90% will be adjusted as 54%occupancy (60% X 90%).

ZONE COMPONENTS

ZONE COMPONENTS

SYSTEM SIZING

ZONE SIZING

Choice Zone AirflowComputation

Space AirflowComputation

Method 1 Peak ZoneLoad

ZoneCfm/Sq. Ft

Method 2 Peak ZoneLoad

CoincidentSpace Loads

Method 3 Peak ZoneLoad

Peak SpaceLoad

Method 4 Sum of SpaceAirflows

Peak SpaceLoad

Two Zone Airflow Sizing Methods

Peak Zone Load and Sum of Space

ZONE SIZING

3 Alternative Space Airflow Sizing Methods AvailableWith Peak Zone Sensible Sizing

ZONE SIZING

Only One Alternative for Space Airflow Sizing WhenZone Sizing is Sum Of Space Airflows.

ZONE SIZING

ZONE SIZING

SPACE 1 SPACE 2

VAVBOX

ZONE SIZING

Zone design CFM

•Maximum zone sensible cooling load

Space air quantity

•Zone CFM /Sq.ft

Zone = 1000 CFM

Two spaces 600 ft and 900 ft.Total Area.1500 ft

Zone CFM /ft = 1000/1500 (.66 CFM /ft)

1st space (600 ft) x (.66 CFM /ft) = 400 CFM

2nd space (900 ft) x (.66 CFM /ft) = 600 CFM

ZONE AIRFLOW COMPUTED USING PEAK ZONE LOAD.SPACE AIRFLOW COMPUTED USING ZONE CFM/ Sq.Ft

METHOD 1:

ZONE SIZING

SPACE 1 SPACE 2

VAVBOX

600 ft² 900 ft²

1000 CFM

400 CFM 600 CFM

METHOD 1:

ZONE SIZING

Zone design CFM

•Maximum zone sensible cooling load

Space air quantity

•Space sensible cooling load at the time the Zone peaks

Zone = 1000 CFM 21600 Btu/hr sensible

•Time August 1600 hrs

•Two spaces

Space loads @ August 1600 are 8000 Btu/hr and 13600 Btu/hr sensible(even if larger load exits)

1st (1000CFM) x (8000 Btu/hr) / (21600 Btu/hr) = 370 CFM

2nd (1000CFM) x (13600 Btu/hr) / (21600 Btu/hr) = 630CFM

Zone airflow computed using peak zone load.Space airflow computed using coincident space loads.METHOD 2:

ZONE SIZING

SPACE 1 SPACE 2

VAVBOX

1000 CFM

370 CFM 630 CFM

8000 Btu/hr 13600 Btu/hr

August 1600 Hrs

METHOD 2:

ZONE SIZING

Zone design CFM

•Maximum zone sensible cooling load

Space air quantity

•Maximum sensible cooling load for each space

Zone max. sensible August 1600 1000 CFM

1st Space max. sensible August 1300

•550 CFM

2nd Space max. sensible August 1600

•630 CFM

Space CFM total 550 + 630 = 1180 CFM

Zone airflow computed using peak zone load.Space airflow computed using peak space load.

METHOD 3:

ZONE SIZING

SPACE 1 SPACE 2

VAVBOX 1000CFM

550 CFM 630 CFM

August1300 Hrs

August1600 Hrs

METHOD 3:

ZONE SIZING

Zone design CFM

•Sum of peak space design airflows.

Space air quantity

•Maximum sensible cooling load for each space.

1st space August 1300 550 CFM

2nd space August 1600 630 CFM

Zone design airflow 1180 CFM Total

Zone airflow computed using sum of peak space airflows.Space airflow computed using peak space sensible load.METHOD 4:

ZONE SIZING

SPACE 1 SPACE 2

VAVBOX

1180 CFM

550 CFM 630 CFM

550630+METHOD 4:

ZONE SIZING

Method Zone DesignCFM

Space 1DesignCFM

Space 2DesignCFM

1 1000 CFMZone Peak

400 CFMCfm/ ft

600 CFMcfm/ ft

2 1000 CFMZone Peak

370 CFMCoincident

630 CFMCoincident

3 1000 CFMZone Peak

550 CFMSpacepeak

630 CFMSpacepeak

4 1180 CFMSum ofSpace Peaks

550 CFMSpacepeak

630 CFMSpacePeak

ZONE SIZING

• Which method would you use?• Why?• Use different methods for different systems?

Choice Zone AirflowComputation

Space AirflowComputation

Method 1 Peak ZoneLoad

ZoneCfm/Sq. Ft

Method 2 Peak ZoneLoad

CoincidentSpace Loads

Method 3 Peak ZoneLoad

Peak SpaceLoad

Method 4 Sum of SpaceAirflows

Peak SpaceLoad

Eight StepProcedure

Compute Loads for All Spaces

Sum Space Loads to Get Zone Loads

Determine Zone and Space Airflows

Compute Sizes for Zone Equipment

Determine System Airflow Rates

Fans & Outdoor Ventilation Rates

Simulate System Based on Sizing Above

ASHRAE Heat Extraction Corrects Loads to Actual

Identify Peak Coil Loads From Simulation

Report Results

SYSTEM DESIGN OVERVIEW

Generating Reports

Print/viewDesign data

DesignCalculationReports• Reports Are RTFDocuments

• Extensive List ofGraphical Outputs

• Reports SelectedBefore Calculation

• Option to View onScreen or Print

• Air System SizingSummary - CentralCooling Coil Sizing

PLANTS

Equipment & Controls ProvidingCooling and/or Heating to Coils inone or more air systems

Examples: Chiller Plants, Hot WaterBoiler Plants and Steam BoilerPlants

User Models “Generic” or Specific“User-defined “

Can Serve Up To 250 Air Handlers

PLANTS

Plants

PLANTS

PLANTS

Plants

PLANTS

PLANTS

Hourly LoadProfile

PLANTS

PLANTS

CHILLED WATER PLANT

PLANT

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