Hello fellow modelers! Happy new year!
Background- In an attempt to model an air loop (variable volume, VAVs) with water-to-air heat pump coils (heating and cooling) a Unitary system(s) has been used in Open studio v3.4. The desired control type is Setpoint - air loop is to provide a range of tempered air temperatures based on season (~55F to 65F)
Heating coil is functioning as expected, however cooling coil is not. Upon reviewing these threads on unmet hours, a few alternates have been tried with no resolution. Solution 1- Eplus migration & change load to SP with setpoint set to after the heating coil. Result- The load is not seen by the coils and temperature is delivered at 74-75F (zone temp)
Solution 2- More eloborate- creating one Unitary system/ component. It is understood that when using Setpoint control, only 1 coil/component can be used.Change in eplus include -Remove all other components in Unitary system (fan, supplemental coil, heating coil), except for heating or cooling coil -Include Fan on Air loop -Modify node connections so that Unitary system represents only the coil -SPMs on each Unitary system/coil outlet node Result- Cooling coil still does not activate.
Solution 3- Leave the system on load control. Result- temperatures coming out of the coil are all over the place with temperatures dipping as low as 44F. Note that CW is being supplied at 85F with district cooling source so CW loop capacity is clearly not the reason.
Discussion-
Why doesn't the setpoint control with specified SPM on AHU supply out node act as intended?
How is it that control type load which is referncing one zone control act better than setpoint?
Why is the cooling coil over cooling when load control is selected?
Here is a snip to the component features in energy plus- 
Looking forward to your insights here!
