OpenStudio-HPXML v1.4.0
OpenStudio-HPXML version 1.4.0 has been released. The OpenStudio-HPXML workflow uses HPXML building description files to run residential simulations on the Department of Energy's OpenStudio/EnergyPlus building simulation platform.
Two packages are available, a minimal zip with a handful of weather files and a full zip with all US TMY3 weather files. OpenStudio-HPXML v1.4.0 uses OpenStudio v3.4.0, EnergyPlus v22.1.0, and a proposed HPXML v4.0. Please visit the OpenStudio-HPXML v1.4.0 documentation for instructions on how to get started, how to generate an appropriate HPXML file, etc.
New Features
- Updates to OpenStudio 3.4.0/EnergyPlus 22.1.
- High-level optional
OccupancyCalculationType
input to specify operational vs asset calculation. Defaults to asset. If operational,NumberofResidents
is required. - Allows calculating one or more emissions scenarios (e.g., high renewable penetration vs business as usual) for different emissions types (e.g., CO2e).
- New ReportUtilityBills reporting measure: adds a new results_bills.csv output file to summarize calculated utility bills.
- Switches from EnergyPlus SQL output to MessagePack output for faster performance and reduced file sizes when requesting timeseries outputs.
- New heat pump capabilities:
- Breaking change: Replaces the
UseMaxLoadForHeatPumps
sizing option withHeatPumpSizingMethodology
, which has three choices:ACCA
: nominal capacity sized per ACCA Manual J/S based on cooling design loads, with some oversizing allowances for larger heating design loads.HERS
(default): nominal capacity sized equal to the larger of heating/cooling design loads.MaxLoad
: nominal capacity sized based on the larger of heating/cooling design loads, while taking into account the heat pump's capacity retention at the design temperature.
- Allows the separate backup system to be a central system (e.g., central furnace w/ ducts). Previously only non-central system types were allowed.
- Heat pumps with switchover temperatures are now autosized by taking into account the switchover temperature, if higher than the heating design temperature.
- Allows
BackupHeatingLockoutTemperature
as an optional input to control integrated backup heating availability during, e.g., a thermostat heating setback recovery event; defaults to 40F.
- Breaking change: Replaces the
- New water heating capabilities:
- Allows conventional storage tank water heaters to use a stratified (rather than mixed) tank model via
extension/TankModelType
; higher precision but runtime penalty. Defaults to mixed. - Allows operating mode (standard vs heat pump only) for heat pump water heaters (HPWHs) via
extension/OperatingMode
. Defaults to standard. - Updates combi boiler model to be simpler, faster, and more robust by using separate space/water heating plant loops and boilers.
- Allows conventional storage tank water heaters to use a stratified (rather than mixed) tank model via
- New capabilities for hourly/sub-hourly scheduling via schedule CSV files:
- Detailed HVAC and water heater setpoints.
- Detailed heat pump water heater operating modes.
- EnergyPlus modeling changes:
- Switches from ScriptF to CarrollMRT radiant exchange algorithm.
- Updates HVAC fans to use fan power law (cubic relationship between fan speed and power).
- Updates HVAC rated fan power assumption per ASHRAE 1449-RP.
- Allows specifying a
StormWindow
element for windows/skylights; U-factors and SHGCs are automatically adjusted. - Allows an optional
AirInfiltrationMeasurement/InfiltrationHeight
input. - Allows an optional
Battery/UsableCapacity
input; now defaults to 0.9 x NominalCapacity (previously 0.8). - For CFIS systems, allows an optional
extension/VentilationOnlyModeAirflowFraction
input to address duct losses during ventilation only mode. - Breaking change: Each
VentilationFan
must have one (and only one)UsedFor...
element set to true. - BuildResidentialHPXML measure:
- Breaking change: Changes the zip code argument name to
site_zip_code
. - Adds optional arguments for schedule CSV files, HPWH operating mode, water heater tank model, storm windows, heat pump lockout temperature, battery usable capacity, and emissions scenarios.
- Adds support for ambient foundations for single-family attached and apartment units.
- Adds support for unconditioned attics for apartment units.
- Adds an optional argument to store additional custom properties in the HPXML file.
- Adds an optional argument for whether the HPXML file is written with default values applied; defaults to false.
- Adds an optional argument for whether the HPXML file is validated; defaults to false.
- Breaking change: Changes the zip code argument name to
- ReportSimulationOutput measure:
- Breaking change: New "End Use: <Fuel>: Heating Heat Pump Backup" output, disaggregated from "End Use: <Fuel>: Heating".
- Adds "Energy Use: Total" and "Energy Use: Net" columns to the annual results output file; allows timeseries outputs.
- Adds a "Fuel Use: Electricity: Net" timeseries output column for homes with electricity generation.
- Adds optional argument for requesting timeseries EnergyPlus output variables.
- Adds ability to include
TimeDST
and/orTimeUTC
timestamp column(s) in results_timeseries.csv. - Timestamps in results_timeseries.csv are output in ISO 8601 standard format.
- Allows user-specified annual/timeseries output file names.
- ReportHPXMLOutput measure:
- Adds "Enclosure: Floor Area Foundation" output row in results_hpxml.csv.
- Adds support for shared hot water recirculation systems controlled by temperature.
- Relaxes requirement for
ConditionedFloorAreaServed
for air distribution systems; now only needed if duct surface areas not provided. - Allows MessagePack annual/timeseries output files to be generated instead of CSV/JSON.
Bugfixes
- Adds more stringent limits for
AirflowDefectRatio
andChargeDefectRatio
(now allows values from 1/10th to 10x the design value). - Catches case where leap year is specified but weather file does not contain 8784 hours.
- Fixes possible HVAC sizing error if design temperature difference (TD) is negative.
- Fixes an error if there is a pool or hot tub, but the pump
Type
is set to "none". - Adds more decimal places in output files as needed for simulations with shorter timesteps and/or abbreviated run periods.
- Timeseries output fixes: some outputs off by 1 hour; possible negative combi boiler values.
- Fixes range hood ventilation interaction with infiltration to take into account the location of the cooking range.
- Fixes possible EMS error for ventilation systems with low (but non-zero) flow rates.
- Fixes documentation for
Overhangs/Depth
inputs; units should be ft and not inches. - The
WaterFixturesUsageMultiplier
input now also applies to general water use internal gains and recirculation pump energy (for some control types). - BuildResidentialHPXML measure:
- Fixes units for "Cooling System: Cooling Capacity" argument (Btu/hr, not tons).
- Fixes incorrect outside boundary condition for shared gable walls of cathedral ceilings, now set to adiabatic.