Release of version 1.1.3 of Tonatiuh

We just released version 1.1.3 of Tonatiuh. This is a minor release version of the program. Its main characteristics are the following:

• It corrects a bug detected in the program's Update Manager of version 1.1.2, which precluded the Update Manger to fulfill its function.
• It introduces changes in the core of the Tonatiuh program that improves and simplified its structure.
• It adds two new shape plug-in to the list of standard Tonatiuh plug-ins: The trough and the surface of revolution versions of the standard non-imaging Trumpet-like concentrator.

Because of the bug in the Update Manager of Tonatiuh version 1.1.2, the new release of the program (version 1.1.3) has still to be downloaded and installed as in previous versions, i.e., by downloading the installer from the "Downloads" tab of the Tonatiuh website and executing it.

As usual, the trough or translational sweeping version of the trumpet-like concentrator plug-in represents only one-side of the translational sweeping trumpet. This allows Tonatiuh users to define complex n-sided trumpet-like concentrators by combining several of these sides and selecting appropriately their input and output lengths.

The following figure shows the parameters that are used in Tonatiuh to define the translational sweeping version of the trumpet-like concentrator shape plug-in added to the new release of the program.

From Tonatiuh Blog Figures

Contrary to others rotational geometry standard Tonatiuh shape plug-ins, the rotational geometry version of the trumpet-like plug-in those not allow the user to define the rotational sweeping angle, but assumes that this angle is always 360 degrees. This limitation will be corrected in future versions of this plug-in.

The following figure shows the parameters that are used in Tonatiuh to define the rotational sweeping version of the trumpet-like concentrator plug-in added to the new release of the program.

From Tonatiuh Blog Figures

As always, if you find bugs in Tonatiuh or in any of its plug-ins, please, take the time to report those errors using the "Issues" tab in Tonatiuh's website at Googlecode. Furthermore, if you have suggestions on how to improve the program or increase its functionalities, please, let us know, either by adding comments to this post, or better by participating on the corresponding discussion of the Tonatiuh users group.

Best regards. Enjoy!

Parameters of the CHC plug-in

In Tonatiuh release 1.1.2, the latest one as of the writting of this post, we have introduced a new shape plugin, the 2D Compound Hyperbolic Concentrator plug-in, which in Tonatiuh is called "Trough_CHC".

The mathematical model defining the CHC implemented in the Trough_CHC plug-in is taken from the following article:

William L. Eichhorn, "Generalized conic concentrators", Appl. Opt. 21, 3887-3890 (1982). http://www.opticsinfobase.org/abstract.cfm?URI=ao-21-21-3887

The plug-in, when added in Tonatiuh as a child to a TShapeKit node, implements one side of a 2D Compound Hyperbolic Concentrator.

From Tonatiuh Blog Figures

As indicated in the above figure, the geometry is defined by the following 5 parameters:

• r1, the distance in the x-direction from the origin of the CHC implicit local coordinate system to the middle of the lower border, oriented in the z-direction and centered around the x-axis. In the negative x-direction, r1 is also de distance in x-axis where the focus of the branch of the hyperbola represented by the plug-in is located (point F in the figure).
• p1,  the distance in the x-direction from the origin of the CHC implicit local coordinate system to the middle of the the upper border, oriented in the z-direction and centered around the x-axis.
• lengthX1, the length of the lower border, oriented in the z-direction and centered around the x-axis.
• lengthX2, the length of the upper border,oriented in the z-direction and centered around the x-axis.
• height, the distance in the y-direction between the lower and the upper border.

By defining lengthX1 and lengthX2 appropiately, it is possible to combine several trough CHC plug-ins to represent a large variety of hyperbolic concentrators. As an example, the figure below shows an Hexagonal CHC constructed using six troguh CHC plug-ins.

From Tonatiuh Blog Figures

Tonatiuh’s website number of visits and bounce rate are growing fast

Tonatiuh’s website started on June 28, 2008. Thus, we are currently in the day 143 of the third year since the opening of the website. With only 39% of the third year of the website passed by, today the number of visits to the Tonatiuh website has exceeded the total number of visits to the website during the previous year. The fact that the number of visits to the Tonatiuh’s website is increasing at an exponential rate is an indication that Tonatiuh is increasingly kwon and used all over the world.

From Tonatiuh Blog Figures

Another indication of the consolidation of Tonatiuh as a reference program for the analysis of the optical and energy behavior of solar concentrating systems is the continuous increase in Tonatiuh's website “Bounce Rate”. According to the information shown in Figure 1, more than 63% of Tonatiuh website’s visitors are recurrent visitors.

Release of version 1.1.2 of Tonatiuh

We just released version 1.1.2 of Tonatiuh. This is a minor release version of the program. Its main characteristics are the following:

• It incorporates an Update Manager, which allows the users to check if there is available a newer version of the program than the one she or he is using, and to download it in case it is available.
• It adds a new shape plug-in to the list of Tonatiuh standard shape plug-ins. This new shape plug-in named "ShapeTroughCHC" allows the user to create trough-like Compound Hyperbolic Concentrators.
• It fixes the error associated with the lack of immediate response of a Tracker to user-induced changes in the transformation of its parent TShapeKit separator or in any of its ancestors.
• It fixed the error associated with the brief appearance of a ghost window when opening the Sun Position Calculator.

Figure 1 shows a view of a parabolic trough working in tandem with a Compound Hyperbolic Concentrator acting as a secondary concentrator.

From Tonatiuh Blog Figures

We are starting a tutorial series to illustrate the use of Tonatiuh

To illustrate the use of Tonantiuh we are starting today a tutorial series, which will be posted in the wiki of the main Tonatiuh website (tonatiuh.googlecode.com).

The tutorial that starts the series will explain how to use Tonatiuh to model and analyze a tower system with 500 one-facet small heliostats.

From Tonatiuh Wiki Figures

This tutorial will explain how to insert "tracker" plug-ins in the modeling of the heliostat field to ensure that when the user changes the sun position the heliostats are  automatically reoriented so that they keep directing their reflected sunlight towards the receiver located on top of the tower.

In addition, the tutorial will also explain how to use the scripting capabilities of Tonatiuh to automate the generation of an optical efficiency matrix for the solar heliostat field.

To access the index of the tutorial series, please, follow this link.

Please, give us feedback, so that we can continue improving Tonatiuh, and providing you the tools and information you need to use it.

Best regards,

Improved instructions to install Tonatiuh's IDE under Windows

One of the many good things of Tonatiuh is that it is build upon one of the best set of open source libraries available (Qt, Simage, Coin3D, SoQt, Marble, Berkeley DB). This allows the program to benefit from the continuous improvement and increase in functionality of those libraries and their related tools.

Under Windows, the recent improvements on the installation and set up tools of the MinGW/MSYS compilation and linking environment and of the Qt, Coin3D and Marble libraries has resulted in a drastic simplification and a dramatic reduction in the time needed to install and configure the Tonatiuh's development environment.

Now, if you follow the updated instructions posted on the Wiki of the Tonatiuh website regarding how to install and configure the development environment of Tonatiuh under Windows XP, Windows Vista, and Windows 7, you will need just two to three ours to:

• Install the complete development environment,
• Download Tonatiuh's source code from its Googlecode SVN server,
• Build the latest stable version of the program from its source code, and
• Be ready to contribute to the improvement of the program, should you decide to do so. 

These are good news to any one interested in being able to build the latest version of Tonatiuh without having to wait until the next official program release, or to any one interested in collaborating in the development of the program.

To access the updated wiki instructions regarding how to install and configure Tonatiuh's development environment, please, go to this link.

Release of version 1.1.1 of Tonatiuh

We just released version 1.1.1 of Tonatiuh. This is a minor version of the program. The main characteristic of this release is that it incorporates the most recent versions of all of the program's supporting libraries: Qt, Simage, Coin, SoQt, Marble and Berlkeley DB.

As shown in Figure 1, this release is faster than version 1.0.0. Under Windows, it achieved a 14.1% reduction in the average time it needed to cast 6 million rays while simulating the optical behavior of NREL's Solar Furnace in the three computers in which the program was tested. Under Linux this average time reduction reached 15.6%.

From Tonatiuh Blog Figures

The release fixes several small program bugs and introduces both a new version of the Buie's sunshape plugin and a new version of the spherical rectangle plug-in. It also slightly changes the way the user can use Marble to select a given location on the Earth.

As always, if you find bugs in Tonatiuh or in any of its plug-ins, please, take the time to report those errors using the "Issues" tab in Tonatiuh's website at Googlecode. Furthermore, if you have suggestions on how to improve the program or increase its functionalities, please, let us know, either by adding comments to this post, or better by participating on the corresponding discussion of the Tonatiuh users group.

Best regards. Enjoy! 

Release of version 1.1.0 of Tonatiuh

We just released version 1.1.0 of Tonatiuh. This is a relatively major release of the program. It incorporates a signficant new feature to Tonatiuh: SCRIPTING.

From now on, you will be able to automatize some of the recurrent taks that you do with Tonatiuh by writting your own scripts. This new release of the program introduces scpripting just as a proof of concept, we will be expanding the scripting capabilities of Tonatiuh in future program releases.

In addition to scripting, this new release of the program, corrects several detected bugs, improves the general (circumsolar ratio) sunshape plugin, facilitates the storage of Tonatiuh results (photon maps), and makes it possible to inmediately open, within Tonatiuh, any Tonatiuh file just by cliking on the file -once the user associates, in the Operating System he or she is using, the Tonatiuh file extension with the Tonatiuh program.

As always, if you find bugs in Tonatiuh or in any of its plug-ins, please, take the time to report those errors using the "Issues" tab in Tonatiuh's website at Googlecode. Furthermore, if you have suggestions on how to improve the program or increase its functionalities, please, let us know, either by adding comments to this post, or better by participating on the corresponding discussion of the Tonatiuh users group.

Best regards. Enjoy!

OpenSolaris version of Tonatiuh 1.0.1

As indicated in a recent post, we have added OpenSolaris to the list of operating systems for which Tonatiuh is targeted.

If you are interesting in using Tonatiuh under OpenSolaris, please, do the following:

1. Go to the "Downloads" section of the Tonatiuh website at Googlecode.com.
2. Download the archive file "tonatiuh-opensolaris-1.0.1.tar.gz" in a computer running OpenSolaris and extract its content.
3. Find the shell file "Tonatiuh.sh" and execute it.

We have been able to test the above procedure in only one PC running OpenSolaris. Thus, if the procedure works for you, please, let us know. If it does not work, please, also let us know, and if possible, please, provide us with the details of what went wrong, so that we can try to fix it.

Release of version 1.0.1 of Tonatiuh

We just released version 1.0.1 of Tonatiuh. This minor release:

• Fixes some programming bugs that, when running Tonatiuh under the MAC OS X, resulted in the user not being able to maximize the program's main window, or in some plug-ins not being loaded.
• Improves the implementation of the ShapeFlatDisk so that now when using this shape as the starting surface from which to cast solar photons into the solar concentrating systems, the origin of the photons are much more uniformly distributed upon the flat disk surface that under the previous implementation of the plug-in.
• Includes two new shape plug-ins (ShapeSphericalRectangle, and ShapeBezierSurfaces).

• Includes one new sunshape plug-in (SunshapeBuie).
  

In future posts, the functionality added by these new plug-ins will be presented, and the use of the plug-ing explained.

As always, if you find bugs in Tonatiuh or in any of its plug-ins, please, take the time to report those errors using the "Issues" tab in Tonatiuh's website at Googlecode.

Best regards. Enjoy!

Tonatiuh is available for OpenSolaris

During the last four weeks we were busy, not only improving Tonatiuh and fixing the bugs reported by the users, but also adding OpenSolaris -a unix-derived operating system (OS) promoted by Oracle- to the list of OS for which Tonatiuh is available.

Very soon the instructions to develop and build Tonatiuh for OpenSolaris, using Oracle's C++ compiler, will be added to the wiki of the main Tonatiuh website.

From Tonatiuh Blog Figures

Being able to use Oracle's standard C++ compiler to make Tonatiuh available for OpenSolaris will help us to ensure that we are developing the program in standard C++, and that we are not introducing compiler-specific dependencies in our code.

With this new addition, the number of OS for which Tonatiuh is available reaches four:

• Windows (XP, Vista, and 7),
• Mac OS X,
• Linux (Ubuntu, Kubuntu, Open SuSE), and
• OpenSolaris.

Release of version 1.0.0 of Tonatiuh

We just released version 1.0.0 of Tonatiuh. This new release presents significant advances over previous ones. From a user point of view, the most important feature of the new release is the parallel computing capabilities.

Tonatiuh release 1.0.0 is able to detect the number of available processors in the computer it is running and adjust the number of parallel running threads it uses to execute the ray tracing loop accordingly.

The introduction of these parallel processing capabilities resulted in dramatic cuts in the time needed to execute the ray tracing loop. As shown in the Table, the number of seconds needed to trace 6 million rays over the geometry of the NREL Solar Furnace and the sun position configuration defined in the file “SolarFurnace_normal.tnh” that can be found in the Downloads section of the Tonatiuh website at Google code decreased from an average of 129 seconds under Windows and 70 seconds under Linux to an average of 26 seconds under Windows (79.9% decrease) and 21 seconds under Linux (69.4% decrease).

From Tonatiuh Blog Figures

Obviously, the reductions are the more significant the greater the number of available processors in the computer. This is proven by the fact that the larger decreases in the ray tracing loop execution time shown in the above table correspond to the computer labeled PC2, which is the only Quad-Core machine of all the computers used in the comparison –the other computer are Dual-Core machines.

Parallelization is not, however, the only relevant feature of Tonatiuh release 1.0.0. The new release uses the latest Qt, Simage, Coin, SoQt and Marble libraries. It uses Qt version 4.6.2, Simage version 1.7.0, Coin version 3.1.3, SoQt version 1.5.0, and Mable version 0.8. In addition, for the Windows version, the MinGW compiler was updated to make it able to use gcc version 4.5.

The code of the new Tonatiuh release underwent important architectural changes with respect to the previous one in order to implement parallelization. Furthermore, it was reviewed to eliminate redundancies, simplify the architecture, and achieve additional performance gains. The SceneModel class was simplified and the InstanceNode and the PhotonMapDefault classes were improved and speed up by selectively replacing the use of QList classes by the use of QVector classes, among other things.

Performance comparison of Tonatiuh releases 0.9.4 and 0.9.5

One way to quantify the advances in performance obtained with every new release of Tonatiuh is to compare the time each release of the program takes in tracing the same number of rays throughout the same solar concentrating geometry and sun position configuration.

We decided to do this by measuring the time each new release of the program takes in tracing 6 million rays over the geometry of the NREL Solar Furnace and the sun position configuration defined in the file “SolarFurnace_normal.tnh” that can be found in the Downloads section of the Tonatiuh website at Google code.

Since the execution time of a program strongly depends on the computational capabilities of the computer in which the program is run (i.e., the CPU type, the frequency of its clock, the amount of RAM available, etc.), and in the operating system used, we have selected a sample of three computers in which to measure the time each new release of Tonatiuh takes in casting 6 million rays over the NREL solar Furnace configuration previously mentioned, under both Windows 7 and Kubuntu 9.10.

The results of the comparison between the current release of Tonatiuh (version 0.9.5) and the previous one (version 0.9.5) are shown in the following figure.

From Tonatiuh Blog Figures

From these results the following conclusions can be drawn:

• The two releases of Tonatiuh run almost two times faster under Linux than under Windows. This may be due to a difference in the quality of the executable code generated by the Windows C++ compiler (MinGW) and the Linux C++ compiler (GCC).
  
• Since neither of the two releases make use of parallel computing capabilities within their ray tracing loop they run faster in the computers operating at the higher frequency rates.
  
• The increase in ray casting performance of release 0.9.5 with respect to the previous release of Tonatiuh is substantial. In casting 6 million rays towards the NREL Solar Furnace, it takes of the order of 18.5% less time under Windows 7, and of the order of 6.7 % less time under Linux, than Tonatiuh release 0.9.4.

Release of version 0.9.5 of Tonatiuh

On March 25, Tonatiuh version 0.9.5 was released. This new release of Tonatiuh is available for downloading at the program's main website: tonatiuh.googlecode.com

This new version of the program offers the following improvements over the previous version:

• It improves the shape plugin "Parabolic_rectangle" so that the new version of the plugin is better suited to simulate the geometry of rectangular heliostat parabolic facets.

• It allows the user to select the "active side" of a surface from a Coin 3D point of view (i.e. just for representation purposes). This active side determines how the surface is illuminated within Coin and represented in Tonatiuh's 3D window. While it does not change the ray tracing behavious of the shapes, it can greatly improve the way it is visualized.

• It adds a new button to the GUI that allows the user to change the view of the scene, in order to view it from the Sun perspective, i.e. from the surface from which the sun rays are cast into the solar concentrating system.

• I adds a new entry to the View menu named "Grid settings..." which allow to change the overal dimension of the reference grid, as well, as the dimension of the cells that compose it.

• It solve a bug in the program related to the export of the photon map in global coordinates.

• It streamlines parts of the core raytracing functions of the program to speed it up.
  

Release of version 0.9.4 of Tonatiuh

On February 26, Tonatiuh version 0.9.4 was released. This new release of Tonatiuh is available for downloading at the program's main website: tonatiuh.googlecode.com

This new version of the program offers the following improvements over the previous version:

• It fixes two bugs found in the code. One that precluded the program to show in the 3D pane of the GUI the rays traced by the program, and other that made the program crash when the user changed the position of the Sun, after tracing rays.

• It introduces a new type of plugin: The random number generator or uniform deviate. While in previous releases of the program random numbers where generated by a specific class within the core program. In this new release the architecture of the program, and its user interface, has been changed to allow the user to specify which random number generator plugin he or she wants to use. In addition to this, two state-of-the-art random number generators have been coded into plugin form to give the users the option to select either of them, or two develop and use their own plugin.

Increased Twitter and Facebook integration

The posts on this blog, the modifications in the "updates" and "downloads" sections of the main Tonatiuh website, and the posts in the "Journal Entries" section of the Tonatiuh project pages at Ohloh will all be published in "The Tonatiuh Chronicles" Facebook page, and the "tonatiuhrt" Twitter page.

This blog is now advertised in Facebook

I just created a page in Facebook about this blog. The name of the page is also "The Tonatiuh Chronicles". Its link is here.

I used RSS Graffiti to ensure that the posts on this blog are published on the Wall of the Facebook page.

Optical simulation of large solar scale tower system

From Tonatiuh Blog Figures

We are starting to test the capabilities of Tonatiuh to simulate the optical behavior of large scale solar tower systems. The tower system shown in the Figure has a North heliostat field of 2268 large heliostats.