Outputs in DELPHIN 6.1

The data description contains the following information:

The file name (1) can in principle be freely defined. However, the specifications of the operating system should be adhered to. In order to avoid problems when distributing or editing data files, special characters should not be used in the name. Spaces, minus or underscores should be used to separate individual words. The name should reflect the output quantity, position and formatting. This facilitates the selection for later use in post-processing.

Clicking on the button to the right of the input field for the physical quantity (2) opens a selection dialogue.

The dialogue lists all possible physical quantities, regardless of whether they are available in the concrete calculation. The type is shown in the first column. The classification is as shown in the overview. The second column contains the name of the quantity. This is a keyword in DELPHIN. An explanation of the quantity can be found in the last column and in the chapter 'Possible output quantitys'. To facilitate the selection, DELPHIN remembers the last selected quantitys and displays them in bold font at the top of the list if necessary. This behaviour can be set by using the checkbox at the bottom left of the dialogue.

In the section 'Conversion and calculation options' there are two selection boxes. The first (3) determines how the output value is calculated when assigned to several elements. The following options are available here:

With the first option (Single), there is always a field output when assigned to several elements. This means that the values of all assigned elements are output at any time. This allows the output of spatial distributions or profiles. The type of possible charts in postprocessing depends on the number of elements selected and the type of simulation (1D or 2D). If only one element is selected, a value output will also be generated as with options 2 to 5. It is recommended to always select option 2 (mean value) for single value outputs.

If several elements have been selected, the following representations can be selected in postprocessing:

1D - Simulation

The two charts above represent the same data in two different ways.

2D simulation

In 2D simulations, the data can be represented directly only as a colour gradient at a point in time.

Post-processing allows even more sectional representations. More information is available in the help:

https://www.bauklimatik-dresden.de/postproc/help/de/index.html

Options 2 to 5 always produce value outputs with one value per time point. These can be displayed as line diagrams (see figure below) and are well suited to show changes over time.

Such outputs are also needed for the damage models contained in the post-processing.

Option 3 is a special case here, because here the sum of the phyical quantity is formed over all selected elements. Of course, this is only possible for summable quantities, such as masses. For non-sumable quantities, such as temperature, this option is not offered. The unit of the output variable is then also adapted. E.g. the unit of the water mass density would be kg/m³. If a spatial integral is selected here, it becomes the water mass in the unit kg for the assigned area.

Options 4 and 5 provide the minimum and maximum values of the assigned area. This can be particularly interesting for damage modelling for worst-case analyses.

The second selection box (4) determines the calculation options for the time course. The following variants can be selected:

When creating new outputs, variant 1 is always used by default.

With variant 2, an average value is formed over the time steps set in the schedule. The values for the internal time steps of the solver are used for this. Variants 4 and 5 are calculated similarly. Here, the respective minimum or maximum value is output over the time step. With small output step widths (⇐1h), there is usually hardly any difference to the normal output.

Time integration is only available for flow outputs. Here, the values are also added up to the internal solver time steps and divided by the time step length. The unit is adjusted in the process. E.g. for an output of the heat flux density, W/m² changes to J/m².

The one-page setting (5) only affects the unit of the physical quantity. The time unit is set in DELPHIN in the model options.

A time schedule (output grid) must be assigned to each data description. Selection field 6 allows a choice of an existing schedule or the creation of a new one. To create, select 'Select or create new…​' from the list.

Then the label of the button to the right of the selection field changes to 'Create New…​'. Clicking on the button 'Edit' or 'Create new…​' opens the dialogue for editing the schedule.

Any number of output grids can be created. However, only two are recommended for most simulations.

For the coarse grid, always take a time step that contains a 12h value (0.5d, 1.5d, 2.5d) in order to avoid that the output always came at 00:00. The 12h section then always alternates the output at midnight and noon. The output grid shown above is also used in the project wizard for the standard outputs.

The above image shows the list of output grids available in a project. Click on the green plus sign to create a new grid. Then the dialogue shown in the following picture opens.

The dialogue shown above allows the setting of an output schedule. This can consist of several intervals. Each interval is identified by the start, the duration and the time grid.

The name is defined in input line 1. This can be any name, but should reflect the time grid to make the selection easier. The output grid shown above has the name '1h' because it has hourly time steps.

In field 2 you specify the number of intervals present. One-interval grids are usually used.

Then there are two list elements in the dialogue. The first (green frame - 3) is for entering the interval parameters. In the lower area (blue frame - 4) the intervals are only displayed.

In the input area one can set the following parameters (always number - space - unit):

The output grid shown in the picture above has the following properties:

Output grids with multiple intervals are useful for very long simulations to reduce the amount of output data. The following figure shows an example:

This output grid is intended for simulations with more than 12 years. In the first year there is a finer output (every hour). In the next 10 years, outputs are only written every 25 days. At the end it goes back to hourly values. From interval 2 onwards, no more starting points are set to ensure that the entire simulation period is covered. You should always enter 0 as the duration in the last interval to avoid missing outputs at the end. The calculated start and end times are then shown in the lower list field for checking.

When a new project is created in DELPHIN, the project assistant opens first. It guides the user to the new project in several steps. Step 5 allows the selection of predefined outputs. The display is different for 1D and 2D simulations. The following section deals with a 1D simulation.

Setting 1 allows to skip the creation of predefined outputs.

Section 2 creates outputs that affect the entire structure. There are 3 profiles (or fields) for temperature, relative humidity and moisture content as well as an integral moisture content (total moisture content). The integral moisture content represents the sum of the moisture contents of all elements of the construction (water, vapor, ice). These 4 outputs should exist in every DELPHIN simulation. Especially the integral moisture content is important to represent the long-term behaviour of the construction. Does the moisture increase more and more or does the moisture content level off at a certain level after a few years?

Area 3 allows the creation of outputs for the surfaces (inside and outside). The temperature and relative humidity on the surface and the heat flux density over the boundaries are offered here. Especially important here is usually temperature and relative humidity at the inner surface. These data can be used e.g. for dynamic mould models to prove the minimum thermal insulation. The transmission heat loss can be derived from the heat flux density (preferably also inside). After confirming this dialogue, one continues with the project wizard. After completion, the new project is displayed in DELPHIN. The output data are usually shown in the upper right corner of the window.

In the image above you can see black and bold and grey and italic data. The outputs shown in black are generated and already assigned to the construction. By clicking on a data set, the assignment is highlighted in the construction window. The first 4 data sets are assigned to the entire construction.

The following 4 outputs for temperature and relative humidity on the surfaces have been created but not yet assigned. This must now be done (see picture below). To do this, first mark the corresponding boundary element (1), then the output you want to assign (2) and finally click on the green 'Assign'-button (3).

In the case of the surface outputs, it would be good to adapt the output file names in this case in order to emphasise more clearly what they represent. For example, by default, one surface temperature is called 'Surface temperature - left side'. The left side of this construction is the surface for outside. Therefore, it would be better to rename the output to 'Surface Temperature Outside'.

For 2D constructions, the output section in the project wizard changes in that the outputs for the surfaces are no longer offered (see picture below). This is because in 2D constructions there is no longer a clear allocation of surfaces and adiabatic surfaces are possible. Surface outputs, like all other outputs, must be added later.

Outputs can be created directly by adding them to the output list or by copying existing outputs. To create outputs, proceed as follows:

Instead of creating a new output, you can also copy an existing one and then adapt it. This procedure is advantageous if the new output is similar in format (physical quantity, formatting, schedule) to the existing one. To copy, select an existing output and click on the 'Copy' button.

It is especially important to define a new name. In a DELPHIN project, there must never be two outputs with the same name so that the output files are named differently. If this should happen, an error message will be displayed at the start of the simulation and the calculation will be aborted.

The outputs for fluxes described above can be assigned both at the boundary and in the field. Here, the sign rule must be observed:

If an assignment contains sides both at the boundary and in the field, the assignment rule for the field applies.

The flux outputs described above are linked to the specific boundary conditions mentioned.

All source outputs described above are determined by the assigned named source models. The assignment to the design must be made to volume elements to which a source model is also assigned. Each assignment thereby defines its own outputs.