KoZiBu - Dynamical Behaviour for Buildings

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What KoZiBu is KoZiBu is a design tool on classical PC for buildings dynamic thermal simulation and it's aimed for design offices, teaching and research organisms. The current "1 Thermal Zone" version may be downloaded for free.

KoZiBu is designed to be multi-languages but currently only French and English are fully implemented.
What KoZiBu is designed for KoZiBu is a software used to analyze dynamic hygrothermal performance of building. It is aimed to conduct studies of heating and cooling strategy, air conditionning or ventilation options, insulating materials to be installed. The main objective of KoZiBu is to forecast the energy consumption, and temperature and humidity evolution range.

It permits to estimate the instant heating or cooling powers needed to maintain a given set-point, or to calculate the indoor temperatures when the heating or cooling system is insufficient. Humidity is treated in the same way.

KoZiBu can be used to investigate the energy performance of buildings of almost any type and size. In addition to performing peak load calculations necessary for mechanical equipment design, KoZiBu also estimates the annual energy performance of the building.

For more details, see the presented CoDyBa samples.
How does it work KoZiBu is based on simply bricks assembled to form a complex building with its equipment. Through the graphical interface, users construct a model of the building's geometry using basic elements (air volumes, walls, windows). Users can add internal loads and HVAC-systems into the created model of the building and perform thermal calculations.

Building screenThe building main screen is like the Windows Explorer.

The building have to be described accurately : the building description is given by the use of a graphical interface, which includes a building tree, similar to Windows Explorer. Within the interface, each "entity" is associated to a graphical representation, that permits to manipulate it by operations of "copy", "paste", "drag-and-drop" type. The explorer makes it possible to reach and to edit each entity.

KoZiBu has no limit in air volumes number (thermal zones) : it can simulate building of any size. The only real limit is the time used for the data input.
Screen shots SEE FURTHER.
Samples Traditional house (1 level, 10 volumes).
Office building (7 floors, 79 volumes).
Audience Engineers, researchers, architects, energy consultants (architecture/engineering firms, utilities, equipement manufacturers), students in engineering and architecture.
Expertise required One day of training is desirable but not necessary for those familiar with building modeling.
Availability The single-zone version of KoZiBu is free (free download).
Partnership Partners are required to continue the development of KoZiBu (please contact Jean NOEL) :
- software developers.
- researchers and manufacturers : to introduce more sophisticated materials.

Platform PC + Windows.
Languages KoZiBu is conceived to be multi-languages. The texts are in a separate file, accesible by a text editor : each one can modify them. Currently, only the English and French labels are complete. For German, Spanish and Italian, translators are welcome.
The software has been built in an Object-Oriented Programming language : C++ (use of an hierarchy of classes to represent the building).
Keywords Energy simulation, energy efficiency, building performance, renewable energy, comfort, thermal analysis, indoor air temperature, dynamic simulation.
Other softwares You can compare KoZiBu with other software, for example : DOE2, TRNSYS, IDA-ICE, APACHE, ESP-r, PLEIADES-COMFIE. The points of comparison can be the size of the treated geometries, the scientific tests carried out and published, the treatment of humidity, the number of output graphs, and the price.

Input The basic data are the building geometry and constitution : air volumes, walls (with the materials of layers and the surface parameters), windows (possibility for solar masks). The main parameters are : the climate (several meteorological files for different french cities are supplied), internal loads (from lighting, persons, equipments), regulators (powers and set-points for temperature, humidity and ventilation).
Output Some hourly result graphs may be viewed to compare selected alternatives. All result graphs can be exported to other packages such as Microsoft Excel or Word for customised report generation. Following graphical output are available :
- building : sensible and latent powers (sum of all air volumes powers).
- air volumes : sensible and latent powers, indoor air temperature, resultant temperature (average of air and walls temperatures), air relative humidity.
- surfaces : absorbed direct and diffuse solar fluxes, surface temperature (useful for thermal comfort evaluation).
- windows : transmitted direct and diffuse solar fluxes, sunlit fraction, direct and diffuse transmission coefficient, global transmission coefficient g.
- regulators : power.
Physical models Numerical algorithms of KoZiBu are specific, but the physical models of KoZiBu are those commonly admitted :

Each air volume can contain an unspecified number of temperature regulators (heating/cooling) with their own power and set-point. Power, set-point and activity are given hourly, per day or by week. Humidity is treated in the same way. In the absence of regulation, the temperature and humidity evolve freely. Regulators have a perfect efficiency.
Taking into account of the mean radiant temperature.
R2C wall model. Wall data is layers (material and thickness), azimuth, tilt, etc.
Calculation of each temperature of surface (wall or window), what allows an evaluation of thermal comfort (otherwise very simplified).
The room occupancy is included.
Internal loads and regulators can have power or control parameters as time dependent functions.
Taking into account of the absorption coefficients and of emission for each wall.
Taking into account of the far masks and shading devices.
Hour-by-hour weather data is used.
At present ventilation with outside (in commercial versions).
Shading devices (venetian blinds, etc.) : a modeling was developed and was tested. A version of KoZiBu includes this modeling. The results are ready to be published, and a preliminary report (in english) is available.

A whole series of functionalities were developed without being integrated into commercial version (for an use of these functionalities or for specific studies, consult Jean NOEL) :

Comfort indices, PPD and PMV (FANGER methods).
Forced aeraulic (flow between air volumes).
Validation The BESTEST benchmark (International Energy Agency) was passed successfully (see report in pdf format). This benchmark is the most precise and the most reliable which exists. Then KoZiBu can simulate the performance of 155 buildings in the BESTEST protocol and in almost all the cases matched the performance of other reference energy programs.

KoZiBu Screen Shots

Materials A predefined materials library exists :

Materials screen
Surfaces The screens of walls and windows are :

Wall screenWall.

Window screenWindow.
Regulators The screens of reagulator and internal loads are :

Heating screenCooling.

Lighting screenLighting.
Results The results are provided in the form of curves in function of time (the output time step is choosen by the user).
An integrated tracer makes it possible to visualize them quickly, and an exportation in the Excel format is possible.

Tracer screen
Weather data The software is provided with the weather files of 10 french cities (Agen, Ajaccio, Carpentras, LaRochelle, Limoges, Macon, Millau, Nancy, Rennes, Trappes).
2000 weather files are available for various cities around the world.
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