Lecture 18: Template Systems and Autosizing Material prepared by GARD Analytics, Inc. and University of Illinois at Urbana-Champaign under contract to the National Renewable Energy Laboratory. All material Copyright 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 Purpose Current Templates Future Templates Template Concepts Using HVAC Templates HVAC Template Structure Typical 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 Thermostat  Purchased Air  Four Pipe Fan Coil  VAV Single Duct w/ Reheat  Packaged 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 Duct  Variable Volume Dual Duct  VAV w/ Power Induction Unit  Heat Pumps  Add automatic autosizing to all templates  Provide “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

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 , !- 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 options  Supply-side equipment sizing  Size and “go” runs with computed sizes  Uses 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 Control  At least 2 design days  Special day schedules for sizing  Zone Sizing, System Sizing and Plant Sizing  Indicate with “Autosize” the inputs to be auto-sized

30 Zone Sizing  Name of Zone  Design cooling supply air temperature  Design heating supply air temperature  Design cooling supply air humidity ratio  Design heating supply air humidity ratio

31 Zone Sizing (cont’d)  Outside air method  Outside air flow per person  Outside air flow  Zone sizing factor

32 Zone Sizing (cont’d)  Cooling design air flow method  Cooling design air flow rate  Heating design air flow method  Heating 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 , !- 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 LOOP  Type 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 temperature  Central cooling/heating design supply air temperature  Sizing Option Coincident or non-coincident

36 Plant Sizing  Design loop exit temperature  Design loop delta T  Name of a PLANT LOOP or CONDENSER LOOP  Loop 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 simulation Note: 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 Sizing Schedules Example - 2 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 Sizing Schedules Example - 3 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;  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 , !Fan Coeff 1 Coeff's for Inlet Vane Dampers , !Fan Coeff , !Fan Coeff , !Fan Coeff , !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 input  Autosizing 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