Lecture 18: Template Systems and Autosizing Material prepared by GARD Analytics, Inc. and University of Illinois at Urbana-Champaign under contract to

Lecture 18: Template Systems and Autosizing

Material prepared by GARD Analytics, Inc. and University of Illinoisat Urbana-Champaign under contract to the National Renewable Energy

Laboratory. All material Copyright 2002-2003 U.S.D.O.E. - All rights reserved

2

Purpose of this Lecture

Introduce Templates—a time saving feature Putting an actual system together in EnergyPlus

(by hand) can be difficult and time consuming Templates provide shorthand way of describing

systems Introduce Autosizing

Some components require sizes that the user may not know immediately

Autosizing asks EnergyPlus to size these automatically

3

HVAC System Templates

Template PurposeCurrent TemplatesFuture Templates

Template ConceptsUsing HVAC Templates

HVAC Template StructureTypical HVAC Systems

Template Example Inputs/Results

4

Template Purpose

HVAC system templates provide a shorthand way of describing selected standard HVAC system configurations

5

Current Templates

Zone ThermostatPurchased AirFour Pipe Fan CoilVAV Single Duct w/ ReheatPackaged Furnace w/ DX Air

Conditioner

6

Current Templates (cont’d)

Purchased Hot and Chilled Water Supply Loops

Single Boiler and Chiller Supply Loops

7

Future Templates

Constant Volume Dual DuctVariable Volume Dual DuctVAV w/ Power Induction UnitHeat PumpsAdd automatic autosizing to all templatesProvide “IDF Segments” for template

systems Multiple Boiler and Chiller Supply Loops Multiple Equipment Condenser Loop

8

Template Concepts

Beneficial for setting up the loops, branches, and nodes

Not as beneficial for fans, pumps, chillers, coils, etc.,

The only "automatic" fields are the object name, node names, and maybe flow rates.

For autosized templates the defaults are already specified

9

Template Concepts (Non-Autosized)

User assigns a template variable for each of the remaining fields in the object for Fans, Coils, Chillers, etc… Advantage: order-independent

keywords to assign values to Disadvantage: mapping the variable

names to object fields is messy, and then the user has to go find the object documentation to understand what the variables really mean

10

Using HVAC Templates

To describe typical HVAC system configurations, a combination of system macro commands is used along with the required macro variable definitions prior to each command

11

HVAC Template Structure

Input File.imf##include HVACTemplates.imf

Regular EnergyPlus objectsRUN PERIOD, 1, 1, 12, 31;. . .HVAC Template commands:##set1 ZoneName = "RESISTIVE ZONE"##set1 AvailSched = "FanAndCoilAvailSched"##set1 HeatSuppAirTemp = 50##set1 CoolSuppAirTemp = 13##set1 HeatSuppAirHR = 0.015##set1 CoolSuppAirHR = 0.010PurchAirZone[]. . .

EP-Macro.exe

EPMIDF FileRegular EnergyPlus objects

after macro processing(“Clean IDF file”)

EnergyPlus.exe

EnergyPlus output files



EP-Launch or RunEplus.bat

12

Typical HVAC Systems

Purchased Air System ZoneThermostat[ ] (once for each zone) PurchAirZone[ ] (once for each zone)

Packaged Furnace w/ DX Cooling ZoneThermostat[ ] (once for each zone) DirectAirZone[ ] (once for each zone) UnitaryAirLoop[ ]

13

Typical HVAC Systems (cont’d)

Single-Duct VAV System w/ OA Option ZoneThermostat[ ] (once for each

zone) VAVZone[ ] (once for each zone) VAVAirLoop[ ] ChilledWaterDemand[ ] HotWaterDemand[ ]

14

Typical HVAC Systems (cont’d)

Single Chiller Supply Plant ChillerSupply1[ ] Condenser1[ ]

Single Boiler Supply Plant BoilerSupply1[ ]

15

Template Example Inputs - Thermostat

##include HVACTemplates.imf ! Command to insert template master file

! Master Zone##set1 ZoneName = "RESISTIVE ZONE" ! Zone name##set1 ZoneCtrlSched = "Zone-Control-Type-Sched" ! Cntrl Type Sched##set1 SnglHeatSPSched = "Heating-Setpoints" ! Single Heat SP Sched##set1 SnglCoolSPSched = "Cooling-Setpoints" ! Single Cool SP Sched##set1 SnglHtClSPSched = "None" ! Single Heat/Cool SP Sch##set1 DualSPHeatSched = "None" ! Dual SP Heat SP Sched##set1 DualSPCoolSched = "None" ! Dual SP Cool SP Sched

ZoneThermostat[] ! Trigger the zone thermostat macro

16

Template Example Results - Thermostat

ZONE CONTROL:THERMOSTATIC, RESISTIVE ZONE Thermostat, RESISTIVE ZONE, Zone-Control-Type-Sched, Single Heating Setpoint, RESISTIVE ZONE SingleHeatSPSched , Single Cooling SetPoint, RESISTIVE ZONE SingleCoolSPSched ; SINGLE HEATING SETPOINT, RESISTIVE ZONE SingleHeatSPSched, Heating-Setpoints; SINGLE COOLING SETPOINT, RESISTIVE ZONE SingleCoolSPSched, Cooling-Setpoints;

17

Template Example Inputs –

Direct Air Zone##set1 ZoneName = "RESISTIVE ZONE" ! Zone name##set1 AvailSched = "FanAndCoilAvailSched" ! System Avail Sched##set1 ZoneSuppAirFlow = 2.0 ! Supply air flow [m3/s]

DirectAirZone[] ! Trigger the direct air zone macro

18

Template Example Results –

Direct Air Zone CONTROLLED ZONE EQUIP CONFIGURATION, RESISTIVE ZONE, ! zone name RESISTIVE ZONE Equipment, ! zone equipment list RESISTIVE ZONE Inlets, ! inlet node list , ! exhaust node list RESISTIVE ZONE ZoneNode, ! zone node RESISTIVE ZONE OutletNode; ! zone outlet node ZONE EQUIPMENT LIST, RESISTIVE ZONE Equipment, ! name DIRECT AIR, RESISTIVE ZONE Direct Air, 1, 1; NODE LIST, RESISTIVE ZONE Inlets, ! name RESISTIVE ZONE AirTermInletNode; ! zone inlet is the direct air DIRECT AIR, RESISTIVE ZONE Direct Air, !- Direct Air Name FanAndCoilAvailSched, !- Schedule name for on/off schedule RESISTIVE ZONE AirTermInletNode, !- Zone Supply Air Node Name 2.0; !- Maximum air flow rate {m3/s}

19

HVAC Sizing Options

Component Sizing

Zone Sizing

System Sizing

Plant Sizing

20

Component Sizing

Components are typically autosized based on specified summer and winter design days.

Global sizing factor optional Sizing factor typically >1.0 Sizing factor can be any value >0 Default 1.0

SIZING PARAMETERS,

1.2; !- sizing factor

21

Zone Sizing

Calculates required supply air volume to maintain zone setpoints

Computes maximum cooling load, heating load and air flow for systems sizing and sizing zone components

Only controlled zones are included in zone sizing calculations

OA flow per person based on total number of people for all PEOPLE statements in zone (schedule values are not applied)

22

Zone Sizing (cont’d)

ZONE SIZING, ZONE ONE, !- Name of a zone 14., !- Zone cooling design supply air temperature {C} 50., !- Zone heating design supply air temperature {C} 0.009, !- Zone cooling design supply air humidity ratio !- {kg-H20/kg-air} 0.004, !- Zone heating design supply air humidity ratio !- {kg-H2O/kg-air} flow/person, !- Outside air method 0.00944, !- Outside air flow per person {m3/s} 0.0, !- Outside air flow {m3/s} 0.0, !- Zone sizing factor design day, !- Cooling design air flow method 0, !- Cooling design air flow rate {m3/s} design day, !- Heating design air flow method 0; !- Heating design air flow rate {m3/s}

23

System Sizing

Calculates design air flow rates and heating and cooling capacities based on specified supply air conditions and zone sizing results

Must use zone sizing objects to force hard sizes (will not read component sizes)

Only controlled zones are included in system sizing calculations

24

System Sizing (cont’d)

SYSTEM SIZING, Unitary System, !- name of an AIR PRIMARY LOOP object sensible, !- type of load to size on 0.0, !- Design (min) outside air volume flow rate {m3/s} 1.0, !- minimum system air flow ratio 0.0, !- Preheat design set temperature {C} 13.0, !- Central cooling design supply air temperature {C} 50.0, !- Central heating design supply air temperature {C} noncoincident, !- Sizing Option no, !- Cooling 100% Outside Air no, !- Heating 100% Outside Air 0.008, !- Central cooling design supply air hum. ratio !- {kg-H2O/kg-air} 0.008, !- Central heating design supply air hum. ratio !- {kg-H2O/kg-air} design day, !- cooling design air flow method 0, !- cooling design air flow rate {m3/s} design day, !- heating design air flow method 0; !- heating design air flow rate {m3/s}

25

Auto-Sizing

Generate sizing report files (.zsz, .ssz)Outside air optionsSupply-side equipment sizingSize and “go” runs with computed

sizesUses all design days and selects max

size

26

Auto-Sizing Calculation

A “Purchased Air” simulation is performed for each zone using user specified Design Day weather Purchased Air: hot or cold air supplied

directly to a zone at a fixed temperature and with infinitely variable air flow.

The Purchased Air simulation yields zone design air flow rates.

27

Auto-Sizing Calculation (cont’d)

The zone design air flow rates are summed to give central air handler coincident or non-coincident design flow rates.

User specified design supply temperatures and the design weather conditions are used to calculate zone and system design heating and cooling capacities.

28

Auto-Sizing Calculation (cont’d)

Coil UAs and other component inputs are obtained by iterating the component models to meet the design outlet conditions

Coil water flow rates are summed to obtain plant loop hot and chilled water flow rates

29

Auto-Sizing Input

Run ControlAt least 2 design daysSpecial day schedules for sizingZone Sizing, System Sizing and

Plant SizingIndicate with “Autosize” the inputs

to be auto-sized

30

Zone Sizing

Name of ZoneDesign cooling supply air temperatureDesign heating supply air temperatureDesign cooling supply air humidity

ratioDesign heating supply air humidity

ratio

31


Outside air methodOutside air flow per personOutside air flowZone sizing factor

32


Cooling design air flow methodCooling design air flow rateHeating design air flow methodHeating design air flow rate

33

Zone Sizing - Example

ZONE SIZING,

SPACE1-1, !- Name of a zone

14., !- Zone cooling design supply air temperature {C}

50., !- Zone heating design supply air temperature {C}

0.009, !- Zone cooling design supply air humidity ratio

0.004, !- Zone heating design supply air humidity ratio

FLOW/PERSON, !- outside air method

0.00944, !- outside air flow per person {m3/s}

0.0, !- outside air flow {m3/s}

0.0, !- zone sizing factor

design day, !- cooling design air flow method

0, !- cooling design air flow rate {m3/s}

design day, !- heating design air flow method

0; !- heating design air flow rate {m3/s}

34

System Sizing

Name of an AIR PRIMARY LOOPType of load to size on

Sensible, latent or total

Design (min.) outside air volumetric flow rate

Minimum system air flow ratio

35

System Sizing (cont’d)

Preheat design set temperatureCentral cooling/heating design

supply air temperatureSizing Option

Coincident or non-coincident

36

Plant Sizing

Design loop exit temperatureDesign loop delta TName of a PLANT LOOP or

CONDENSER LOOPLoop type – heat, cool, condenser

37

Run Control - example

RUN CONTROL, Yes, ! zone sizing Yes, ! system sizing Yes, ! plant sizing No, ! design day full simulation Yes; ! weather file full simulationNote: design days used here just to

size

38

Sizing Schedules Example - 1

SCHEDULE,

Clg-SetP-Sch, !- Name

Temperature, !- ScheduleType

Clg-SetP-WSch, !- Name of WEEKSCHEDULE 1

1, !- Start Month 1

1, !- Start Day 1

12, !- End Month 1

31; !- End Day 1

39


WEEKSCHEDULE, Clg-SetP-Wsch, !- Name Clg-SetP-DSch-We, !- Sunday DAYSCHEDULE Name Clg-SetP-DSch-Wd, !- Monday DAYSCHEDULE Name : Clg-SetP-DSch-Wd, !- Friday DAYSCHEDULE Name Clg-SetP-DSch-We, !- Saturday DAYSCHEDULE Name Clg-SetP-DSch-We, !- Holiday DAYSCHEDULE Name Clg-SetP-DSch-SumDes, !- SummerDesignDay DAYSCHEDULE

Name Clg-SetP-DSch-HighLimit, !- WinterDesignDay DAYSCHEDULE

Name Clg-SetP-DSch-Wd, !- CustomDay1 DAYSCHEDULE Name Clg-SetP-DSch-Wd; !- CustomDay2 DAYSCHEDULE Name

40


DAYSCHEDULE,

Clg-SetP-DSch-SumDes,

Temperature,

23.9, 23.9, 23.9, 23.9, 23.9, 23.9,

23.9, 23.9, 23.9, 23.9, 23.9, 23.9,

23.9, 23.9, 23.9, 23.9, 23.9, 23.9,

23.9, 23.9, 23.9, 23.9, 23.9, 23.9;

No setback for autosizing - will cause oversizing to meet setback recovery within one timestep

41

What Inputs can be Auto-sized?

Indicated in IDD file

FAN:SIMPLE:VariableVolume,…..N3 , \field Max Flow Rate \units m3/s \Autosizeable…..

42

Asking for Auto-sizing

In the IDF file:FAN:SIMPLE:VariableVolume, Supply Fan 1, !Fan Name FanAvailSched, !Fan Schedule 0.7, !Fan Efficiency 600.0, !Delta Pressure [N/M2] Autosize, !Max Vol Flow Rate [m3/S] Autosize, !Min Vol Flow Rate [m3/S] 0.9, !motor efficiency 1.0, !motor in air stream fraction 0.35071223, !Fan Coeff 1 Coeff's for Inlet Vane Dampers 0.30850535, !Fan Coeff 2 -0.54137364, !Fan Coeff 3 0.87198823, !Fan Coeff 4 0.000, !Fan Coeff 5 Main Heating Coil 1 Outlet Node, !Outlet Node VAV Sys 1 Outlet Node; !Inlet Node

43

Summary

Templates are a time saving feature that: Provides a shorthand way of describing systems Assists in the process of putting together

EnergyPlus inputAutosizing helps the user:

Determine the size of equipment needed based on the building description, thermal loads, etc.

Avoids the need to provide a size for some equipment which may not be of interest but is still needed as input for EnergyPlus

Documents

Lecture 18: Template Systems and Autosizing Material prepared by GARD Analytics, Inc. and University of Illinois at Urbana-Champaign under contract to