EnergyPlus Version 7.0 and OpenStudio Legacy Plug-in 1.07 Available

The U.S. Department of Energy (DOE) has released
an updated version of EnergyPlus simulation
software for modeling heating, cooling, lighting,
ventilating, and other building energy flows.
Additionally, a new version of OpenStudio Plug-in
for Google SketchUp is available, which makes it
possible to perform EnergyPlus simulations using
Google's user-friendly 3-D drawing interface.
Visit www.energyplus.gov to learn more and
download EnergyPlus and OpenStudio Plug-in now.

Enhancements in the New Versions

General

* Significant speed increases, most
simulations see up to 20% reduction in execution
time, depending on features used (also speed
increase for many AirflowNetwork simulations and
large models with radiant systems?see below).

Datasets

* New input data sets for HVAC equipment
performance for rooftop packaged air conditioners
and heat pumps (see DXCoolingCoil.idf and RooftopPackagedHeatPump.idf).
* Extended the library of refrigerant data
to include R407a and superheated CO2 properties
(see FluidPropertiesRefData.idf).
* New input data set for exhaust-fired
chiller heater model (see ExhaustFiredChiller.idf).

Input

* Steam is now a "built-in" fluid property.
* Zone Floor Area can be an input -- overrides the calculated amount.

Windows and Daylighting

* International Glazing Data Base (IGDB)
full spectral data can be used directly.

Zone and Surface Models

* Shadowing Model new options: legacy
"convex" Weiler-Atherton or Sutherland-Hodgman
(more robust for non-convex surfaces).
* New input problem checks for surface
geometry including: convexity, collinear
vertices, planar surfaces, and flipped
floors/roofs. For flipped floors/roofs, a fix is attempted.
* Conduction Transfer Function model revised
to improve modeling of mass-less material layers.
* OtherSideCoefficients model extended to
provide controlled surface outside temperature with schedule and limits.
* Design day weather data generation
procedures upgraded for clear sky model and wet-bulb temperature profiles.
* Conduction Finite Difference heat transfer
model now includes options for solution method
and to control node spatial resolution,
relaxation factor, and convergence criteria.
* Improved convergence checks for initial warmup days.

Natural and Mechanical Ventilation

* AirflowNetwork solver enhanced for speed.
* Consolidated outdoor air inputs in HVAC
models to common design object wherever outdoor air rates are specified.
* New proportional control for CO2-based demand controlled ventilation.
* New mixing object for door openings into refrigerated zones.
* New mechanical ventilation controls based
on ASHRAE Standard 62.1 and CEN 15251.

HVAC and Refrigeration

* New model for Variable Refrigerant Flow
heat pump air conditioning systems.
* Ideal loads air system model revised to
include outdoor air and economizer controls,
humidity control, and capacity limits.
* Plant system and component models revised
to improve speed and robustness, model fluid
properties as a function of temperature and
alternative types of fluid, and better flow control.
* Glycol mixtures supported in all plant loop components.
* New dual duct air terminal unit with
dedicated outside air system on one duct and cooling on the other duct.
* New absorption chiller model powered by microturbine generator exhaust.
* Eliminated redundant input fields in compound HVAC objects.
* Added maximum limits for supply air
temperature leaving air terminal reheat coils.
* Radiant-based HVAC system models revised
for significant speed increase when models have a
large number of thermal zones.
* Low temperature radiant zone HVAC model
now includes a "variable off" control mode.
* Simple chilled water coil model has
enhanced autosizing and variable UA for
significant improvements in chilled water flow rate calculations.
* New heat transfer models for buried piping
systems include interaction with building slabs and basement walls.
* Hot water boiler model options for
choosing between entering and leaving water
temperature as basis in performance curves.
* New dedicated outdoor air system HVACTemplate object.
* New HVACTemplate options: static pressure
reset fan curve, screw chiller type, economizer
dewpoint limit, and unitary system design supply temperatures.
* New Refrigeration model for cold-storage
thermal zones served by refrigeration-based zone units.
* Refrigeration condensers now can reject heat to a thermal zone.
* Improved Refrigeration model to compare
the available temperature of heat reclaimed from
a refrigeration condenser to the temperature needed.
* Variable speed fan model upgraded to avoid
unrealistic leaving temperatures at very low flow rates.

Electrical Systems

* New model for chemical battery electrical storage.

Controls and User Functions

* Availability Managers extended to work
with selected ZoneHVAC equipment including:
window air conditioner, unit heater, unit
ventilator, packaged terminal air conditioner,
packaged terminal heat pump, and zone water source heat pump.
* New Setpoint Managers added to: follow
outdoor air temperature, follow system node
temperature, and follow ground temperature.
* Improvements made to how zone equipment is
controlled when sequencing multiple devices in a single zone.
* New overcool option for Zone and AirLoop
HVAC to control high humidity by shifting down
the zone cooling setpoint temperature.
* Added high humidity control option for
air-to-air and water-to-air heat pumps.
* New EMS actuators and calling point for
custom autosizing of input fields in select DX air handling equipment models.
* New EMS actuators for material surface absorptance properties.
* New EMS actuators for Variable Refrigerant
Flow operating mode and terminal unit part-load ratio.
* New EMS actuators for ideal loads air
system supply temperature and humidity ratio.
* EnergyPlus Runtime Language extended to
include built-in functions for generating random
numbers, limited support for minus sign, and
built-in variables for zone timestep and current environment period.

Output

* New thermal comfort reporting based on the
adaptive comfort criteria from ASHRAE Standard 62.1 and CEN 15251.
* New Sensible Heat Gain Component tabular report.
* New results in Envelope Summary and Lighting Summary tabular reports.
* New source energy end use tabular report.

Utilities

* IDF Editor enhancements include: (1)
search and replace any text in a file, (2) easy
node name selection based on names, object,
field, or recently used, and (3) expanded validity checking.
* New auxiliary tool generates performance
curve coefficients for select HVAC equipment.
* CSVproc has been reimplemented and is now
available as a cross-platform tool.
* New EPDrawGUI cross-platform replacement of WinEPDraw.
* New IDFVersionUpdater cross-platform replacement of IDFConverter.
* Enhanced WeatherConverter with several new features.
* EP-Launch can start EPDrawGUI, IDFVersionUpdater, and EP-Compare.

Documentation and Guides

* Documentation has been updated for all documents.

Platforms

* Windows (XP, Vista, Windows 7) 32 and 64 bit versions.
* Linux (Ubuntu 9.04 and above, Redhat 5.4
and above) 32 and 64 bit versions.
* Mac (10.5, 10.6) 32 and 64 bit versions.
* EnergyPlus V 7.0 has been tested on all of these platforms.

And many other enhancements and speed improvements throughout.

Thanks!
The EnergyPlus Team