Dear e-quest users,

Has anyone had success modeling 2-pipe fan coils with electric shoulder?

The system operates using the following schedule:
- Fan coils provide cooling March through December
- Fan coils provide heating December through March
- Supplemental electric heaters will provide heating during October, November, April and May when required.

I was able to model 2-pipe fan coils by connecting 4 pipe fan coil to 2 pipe circulation loop and using schedules to define changeover criteria. This model gave me a high number of unmet load hours, much higher than I expected. As I could not figure out how to model supplemental electric heat I switched back to 4-pipe fan coils and assigned availability schedules to heating and cooling. With this configuration, I tried to use electric baseboards and baseboard schedules based on outside temperature, but my unmet hours went up, offcourse this time in cooling. I tried changing capacities of baseboards and the baseboard reset schedule, all without any success. The only idea that I could think off is to manually calculate heat load and electricity consumption for spring-fall months. This is a huge building with almost hundred of FCs, and I am still hoping there is some better solution.

Any thoughts?

All ideas are greatly appreciated.

Ana