Dears Srs.,

I am simulation a service building with cooling loads, about 4000W/m2 with a schedule 100% activates in all hours. My system is an air handling unit with return and free cooling. The air handling unit has a cooling coil, a heating coil and a direct evaporation cooling coil 100% activated. The system has humidification and the minimum room relative humidity is 30%.  The temperatures of insufflation are 14-20 ºC for cooling and 20-31 for heating. The room set point is 18-27 ºC.

When I run the simulation, in winter the cooling consumption is 0 because the operation of free cooling. On the other hand, in Winter I have consumption of humidification to control the humidity to 30 %. However the direct evaporative cooling coil does not work as I expected because the direct evaporative cooling coil should help in humidification of the rooms. My question is: Why the direct evaporative cooling coil does not work in winter, when I have height consumption of humidification. In practice the direct evaporative coil work all the year.

The Best Regards,

Ricardo