Simulation tab
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Simulation tab
On this tab, the actual simulations are carried out. Five types of simulations are available: Heating design, Cooling design, Energy, Overheating and Daylight.
Figure 83.
When an Energy simulation is carried out, the whole year is simulated, and internal gains (lights, equipment and occupancy) are cut to 60% (user selectable in full ESBO) of given values. This is because buildings only rarely are used to their full capacity.
For Cooling design and Overheating simulations, a statistically selected clear and hot day is simulated over and over until the building has completely adapted, corresponding to a very long spell of identical hot days. Full internal gains according to their schedules as provided by the user are applied. The process is repeated for each month of the year. Results from several of these monthly hot days are kept, corresponding to the peaks of individual rooms, air handling units and the central plant. Note that when results are presented, cooling peaks for different systems will often occur during unexpected months. While air handling units normally peak during the summer as expected, individual rooms may often peak during winter months when the sun stands low.
An Overheating study is very similar to a cooling design study, but instead of looking for peaks in cooling power, it finds the days when room air temperatures are the highest. Overheating simulations are normally used to study buildings with no or limited installed cooling capacity. Note that mechanical cooling equipment is not automatically removed for an overheating study. This must be done manually by the user.
A Heating design study is similar to Cooling design, but a bit simpler. Only a single cold spell is studied, and for this coldest month, a statistically selected cold day is repeated until the building has adapted. Internal gains are assumed to be zero, and no solar radiation is allowed to enter the building. Full ESBO allows some more user configuration of the design conditions.
A Daylight calculation is an advanced ray tracing calculation executed in the Radiance™ lighting simulation tool.
Results
Requested output Click the hyperlink Select to open dialog to specify what diagrams and reports that will be created during the simulation. Note in particular the Plant details option that will provide the time-evolution of key central system variables.
Figure 84.
Simulation
Click on the appropriate Run button, to carry out the desired simulation. Click the one next to All to run all simulations (will run Cooling design, not Overheating). Once a simulation is finished, the (provider specific) standard report is automatically opened. Click on the Report link to reopen this report if it has been closed.
The Report link next to the button for performing All simulations, will open the (provider specific) combination report, where all simulations are presented together.
The Details link will provide access to further (provider independent) reports that may be of interest. In full ESBO, the additional results that have been selected under Results are presented here.
Simulated The time when the latest simulation was run and how many seconds it took.
Clicking Summary, will open an overview screen on a separate tab, which provides overview of the key results of the simulation.
Clicking “Setup” allows you to define key parameters to be applied in the calculation.
Heating design - Setup
Figure 85.
Ventilation The fans can be turned off to consider the heating load without any AHU.
Internal gains The percentage of internal gains determines the percentage of all internal gains as defined in the rooms that should be applied (normally zero. It is customary to size heating without the added benefit of internal gains.)
Weather
Use synthetic weather With synthetic weather, the date of the simulation as well as the Clearness number influences solar radiation. If Clearness number is set to 0 %, the calculation is done without any solar radiation, while 100 % means clear sky conditions.
If a fixed ambient temperature is specified, maximum and minimum dry bulb temperatures within the location are no longer used.
Design period using climate file is used to size the heating wrt. a selected cold period from a climate file. This option may not be fully supported by the standard reports of all providers.
Simulated period Specify the date to be simulated
Click “Run” to start the simulation
Cooling design - Setup
Figure 86.
Internal gains The percentage of internal gains determines the percentage of all internal gains as defined in the rooms that should be applied (normally 100 %).
Weather
Use synthetic weather With synthetic weather, simulations for a hot day of all months are carried out by default, but results are kept only for months where some system or room has a cooling load peak.
Under Cumulative frequency… the user may select the degree of severity of the applied climate data.
If Selected months is selected, and then some specific months are filled in, simulations will only be performed for the selected months. Simulation results (to be viewed under Details) will be saved for all simulated months, not only for the months that show a peak.
Design period using climate file is used to size cooling wrt. a selected hot period from a climate file. This option may not be fully supported by the standard reports of all providers.
Simulated period Specify the date to be simulated
Click “Run” to start the simulation
Energy - Setup
Figure 87
Percentage of internal gains Define percentage of internal gains that should be active for the energy calculation. These factors are applied to account for the fact that buildings only rarely are used to their design capacity.
Climate file allows you to run the simulation with a different climate file.
Click “Run” to start the simulation
Overheating - Setup
Figure 88
Internal gains The percentage of internal gains determines the percentage of all internal gains as defined in the rooms that should be applied (normally 100 %).
Weather
Use synthetic weather With synthetic weather, simulations for a hot day of all months are carried out by default, but results are kept only for months where some room has a temperature peak.
Under Cumulative frequency… the user may select the degree of severity of the applied climate data.
If Selected months is selected, and then some specific months are filled in, simulations will only be performed for the selected months. Simulation results (to be viewed under Details) will be saved for all simulated months, not only for the months that show a peak.
Design period using climate file is used to size cooling wrt. a selected hot period from a climate file. This option may not be fully supported by the standard reports of all providers.
Simulated period Specify the date to be simulated
Click “Run” to start the simulation
Daylight - Setup
Figure 89.
Measure Select which measure to calculate, either daylight factor or illuminance.
Type of sky Select one of 4 standard sky models or a climate based sky. If climate based sky is selected, irradiance values are taken from the climate file at the specified time point.
Precision Detail level of Radiance calculation. Right-click and choose Open to see the specific Radiance settings and to create new sets of settings. For details about the specific Radiance settings, see the Radiance documentation.
Shading Select if controllable shades should be up or drawn.
Calculated time point Time point is only used with illuminance calculation.
Measuring plane Daylight is calculated on measuring planes. For each room a measuring plane is created at the specified height above the floor, with the specified distance to walls and with the specified distance between measuring points.
Click “Run” to start the daylight calculation.
Export results
Results from heating and cooling load simulations in ESBO can be exported to an IFC file. This is done by choosing Export results. The exported file will not contain a full Building Information Model (BIM), but only simulation results for each ifcSpace.
Standard level
Available only if the full IDA ICE application is accessible.
Build model Click to build and open an IDA ICE model of the system.