I am currently creating the proposed design and baseline model for an Air Traffic Control Tower (LEEDv4: NC, 8600 ft2, Location: Germany). The tower has an air cooled server room with a connected electrical load of 22 kW (cooling setpoint: 75°F). The server load accounts for half of the buildings total cooling load.
According to ASHRAE 90.1 App. G the process load should be identical for baseline and proposed design. However, the cooling energy to get the waste heat out of the building differs significantly.
Per Appendix G, system 3 should be used for the baseline system. The proposed design uses fans coil units connected to an air cooled chiller with a low COP of 2.2. In addition there is currently no option to utilize free cooling due to the building construction. The baseline system uses „free cooling“ from November until May which results in a significant lower cooling energy use and low energy cost savings.
Is anyone aware of any exemption for such a building type?
