Use a four pipe fan coil unit as zone level equipment and then assign as many thermal zones as you want to an air loop for your outside air. There are other approaches, but I believe that is the most common for a typical DOAS system.
Yeah but how do I make sure Energy Plus knows to have the DOAS be first priority and then use the FCU to heat and cool for thermostat temperature? My errors file is showing temperature setpoint is zero, it is not zero, so something is going wrong
In the OS interface cooling/heating priority is set by the order they appear/are dropped in. Not quite sure what you're trying to say with 'thermostats are at 0'.
Office building with several small spaces needing small amount of heat to avoid Unmet loads, plus outside ventilation air. I added air loop with heater to supply ventilation air at room air temperature. To meet heat load I added baseboard heater, which worked. But, to model actual design I changed heater to fan coil auto sized. Simulation gave thousands of cfm for the fan coil, with very small temperature difference from room air, and an error saying that this difference was too small, with note that at time of error thermostat set point is 0 degrees. Why the error with the FC?
Because you're probably trying size the equipment to meet load with a neutral air temperature.
There's a BCL measure that creates a central DOAS system (1 per floor) and applies zone level 4 pipe fan coils to zones with a selected space type. The measure includes many user inputs to help construct the DOAS as needed (energy recovery? chilled water? dx? etc...).
I would suggest applying the measure to a copy of your model to see how the DOAS system and zone level FCUs are constructed. You can get an idea of the necessary components and setup, and choose to either proceed with the BCL measure version, or re-build the system to best suit your specific design or application.
The measure can be found in the OS app through the 'Components & Measures' menu > 'Apply Measures Now' > 'Find Measures on BCL' > 'HVAC' > 'Whole System > 'Four Pipe Fan Coil More Design Parameters'
Thank you, I have done this already. I am just having a hard time changing from chiller/boiler to district cooling/heating. I am also having a hard time with where I put thermostat temperatures and sizing temperatures. I don't think the DOAS and FCU's are working together, I am getting way to much energy use, 0 degree setpoint temperatures and and thousands of unmet hours in cooling.
Asked: 2016-02-04 09:00:55 -0500
Seen: 695 times
Last updated: Feb 04 '16
