Ability to undertake a number of simulations to ascertain how well a ventilation system will perform in terms of good air quality under a varying occupant load.

Task

Instructions

1. Access an exemplar model and explore how detailed air flow is modelled using an air flow network. Look at the contaminant description.

Go to your home folder and start up ESP-r. From the top level menu, choose choose open existing and then exemplar options. Select the cellular office model with CO₂ contaminant tracking and open windows from the technical features category. The model should be copied into your home directory.

This model has an air flow network (see glossary 'flow network' and 'network technique') and a contaminants model described for it. Go to browse/edit/simulate and then click on networks/network flow to take a look at the air flow network. Select the flow network (non-graphical) and choose to view a synopsis after accepting the default name for the flow network file. Now exit from there without saving. Choose contaminant from the model definition menu, accept the default name for the contaminants file and choose to display a synopsis. After reviewing the information presented, exit without saving or updating. From the Browse/Edit/Simulate menu choose composition and then choose operational details. Review the occupancy levels and then exit twice i.e. up to the Browse/Edit/Simulate menu.

2. Run a simulation and look at CO₂ levels for the space.

Choose simulation from the model definition menu, choose integrated simulation and choose to run it interactively. After accepting the configuration file name, choose initiate simulation from the integrated simulator menu. Accept the default names for thermal and mass flow results libraries and make a note of these along with their complete path (the path for both libraries has been set to the /tmp/ on Unix/Linux machines so that large amounts of data go to this folder). Invoke simulation and accept the result set description. Make a note of the simulation time step, period and results library size which will now be displayed in the text feedback space. Save simulation results and exit from the simulator.

Choose results analysis in the main project manager window and accept the name of the results library. Choose graphs and then network air/wtr flow. You will need to give the name with complete path of the flow results library here. Choose contaminant @ node and then manager_a and manager_b. Choose CO₂ and display graph of CO₂ concentrations for the simulation period. Exit from here and choose timestep reports, and display numerical values for your graph.

3. Change occupancy level and determine how this changes the amount of contaminant generated.

Go to composition in the model definition menu. This displays the zones definition menu. Choose operation and then manager_a. Choose edit casual gains and increase all occupancy numbers from 9am to 5pm by a factor of six. This now emulates six people in the office during working hours. Exit from this menu saving your changes. Exit up to the Browse/Edit/Simulate menu. Repeat step 2 of this exercise to look at the effect more people have on the air quality.

Study the impact of wind speed and direction on the airflow rates and contaminant levels in these naturally ventilated offices