02 hap-4 4-systems-carrier
TRANSCRIPT
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
SOFTWARESOFTWAREDEMODEMO