[BLDG-SIM] hornets nest?

[Jeff Hirsch]

Mike Andelman wrote:
The frustrating thing for any DOE2 user who's been using the program since it was CalERDA is that some real progress has developed
over the last few years  with 2.1E, 2.2, and PowerDOE.  Now it appears that the progress will be put on hold as we patiently wait
several years for EnergyPlus.

my reply:
The work on DOE-2 has not slowed down; we are continuing at an equal or higher pace than the last 10 years.  We are (like others),
however, putting a lot of time and $ into the user interface's to make the programs easier to use and more reliable.  For DOE-2, we
just finished adding a number of features (which will be in versions posted within the next couple months) including photovoltaic
systems (PV modules/arrays, inverters, plus effects of array mounting including shading of building surfaces), latent/sensible
energy recovery ventilators (ERV's), spaces which include ice rinks (model includes ice/room radiative exchange and under floor
losses/heating system.)  We are continuing work in a number of other areas to improve HVAC models for both design and energy
calculations and will continue to post these versions as they become available.

Doug Maddox wrote:
"Also, is DOE2.2 more friendly to function writing than DOE2.1E? What about
DOE2.3?"

my reply: The function feature is not yet in a posted 2.2 version; it will be available in the next posted update.  It works like
before, but now all HVAC equipment will have "access points."  The later version you refer to (2.3?) is under development and has no
designation (name/number) or release date yet so should not be confused with products we have posted for general use. All versions
we post for general use are ready for such use; all software, however, has bugs ... they just have not yet all been discovered - we
fix ours are quickly as possible when discovered (or at least give you a work-around.)

Our "next generation" program includes a component based HVAC model in which pressure and temperature, and resultant flow, are
explicitly modeled; this allows the detail modeling, for example, of components on a refrigerant loop (like refrigeration systems -
or chillers), as well as secondary coolants (glycol, brine) or water loops. For example, you can describe the refrigeration "plant"
as an interconnection of  evaporator(s), suction lines, compressor(s), high side lines and condenser(s) with controls and also
select a refrigerant; all these components can be fetched from a large library of such components and assembled into a very complex
system. The piping models, for example, allow the definition of a complete real pipe network and the calculation includes details
such as the change in fluid properties, film coefficients, and pipe losses as the working fluid flows through the system.  The coil
models, for example, include DX coils that track frost accumulation and model alternative defrost mechanisms and controls.  The
overall calculation technique includes iteration with a range of algorithms to assure very rapid convergence to a "correct"
solution.

Again this is NOT a product; it is a product research project in the early stages of beta. At this time only a subset of HVAC
equipment is available in this new program; our focus at this time is refrigeration and HVAC systems for facilities like
supermarkets and refrigerated warehouses. A working beta version is available; it is not intended for general distribution. We
expect it to take at least a year before the full range of HVAC equipment is implemented and longer to complete beta testing.  Those
interested in trying it out are welcome to ask for details.  Like our other "engines", if a general release product results from
this project it will be freeware.
---
Jeff Hirsch
James J. Hirsch & Associates
Building Performance Analysis Software & Consulting
12185 Presilla Road
Camarillo, CA 93012-9243 USA
phone: (805) 553-9000
fax: (805) 532-2401
email: Jeff.Hirsch at DOE2.com
web: http://DOE2.com


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