Modeling the Heating and Cooling Portions of Preconditioned Mechanical Ventilation

Some mechanical ventilation systems may precondition air by either heating or cooling it. These heating and cooling systems need to be accounted for in the model. To model a mechanical ventilation preconditioning system in Ekotrope, first model the heating and cooling portions of the system with appropriate size, efficiency values and with rough estimates for the percent heating and/or cooling loads. Then, model the mechanical ventilation:

1. Set the flow rate on any existing Mechanical Ventilation to 0. Be sure to write the original values down so you do not forget them. When we finish modeling the preconditioned ventilation system, restore the other ventilation system(s) to their original value(s).
2. Add a new Mechanical Ventilation
3. Input the correct type, flow rate, and wattage (you may need to convert hp -> watts)
4. For preconditioning systems shared by two or more dwelling units, divide the flow rate and wattage by total number of dwelling units served.
5. Save the project

Finally, calculate the heating and/or cooling loads associated with this newly added mechanical ventilation:

1. From the project info page and download the Plan Diagnostics spreadsheet.
2. Open the downloaded file in Excel
   1. To compute percent heating load, divide the Ekotrope rated mechanical ventilation heating load (cell C27) by the total heating load (cell C30). This number will be negative, but you can simply flip the sign to obtain your percent heating load. E.G: -.1427 = 14.27% heating load
   2. To compute percent cooling load, divide the Ekotrope rated mechanical ventilation cooling load (cell C13) by the total cooling load (cell C31)
3. Use the value we just calculated above for percent heating load or percent cooling load.
4. Add a new distribution system to handle this new load.
5. Save the project.
6. You are done!