Controlling 2 zones by VAV system and EnergyPlus AirLoopHVAC:UnitarySystem: "SetPoint" [closed]

asked 2022-04-03 14:35:11 -0500

Melina's avatar

Hello. I have a two-storey residential building, and because of different occupancy, I want to have two thermal zones: first floor and second floor. To do so, I have defined two zones, and each has an Airterminal: Single duct:VAV: no reheat. Also, I have defined an AirloopHVAc:Unitary system, and I'm not sure whether this is needed or not. From the examples that exist in EP version 9.5.0, I realized that I should define an AirloopHVAc: Unitary system. Still, I'm not exactly sure that this unitary system is which part of the system and even this is necessary or not, But I made sure to give the inlet and outlet node of this system correctly with the help of examples in version 9.5.0. I'm following is related to a commercial (office) building and is about 2000 m^2, but mine is a 150 m^2 house, so I do not want to copy and paste the HVAC system blindly from the example. My problem is that the example (5Zone_Unitary_VSDesuperheater) has defined a return zone and a return plenum, but I don't think this is a good idea for a house so I have not defined this part. Without an airloopHVAC: return plenum, my 2-zone building model works (I mean, there is no error after simulation). The tables show that there is HVAC heating and cooling energy consumption, and the numbers are reasonable and close to what I have from my previous simulations for this house (but as a single zone). The problem is that when I open the variable file, the temperature of both zones shows that these zones are not controlled at all. The temperature reaches less than 10C, but the set point for even unoccupied hours is not 10C (is 22C). This is obvious that the energy is wasted, but I'm not sure why this is happening? Is this because I have not defined the return plenum and return path, and I only have the supply path? there is not even one day that I can see that the temperature is being controlled! Can you help me and say what can be the source of the problem? Because EP doesn't give me any errors (and warnings are not related) I have no idea what should I do. I have to mention that most of the time the runtime fraction for the heating coil is 1 and the dampers are nearly fully open and my city is heating dominant.

Also, from the comments on this website (unmet hours) I realized that when I define the AirloopHVAc:Unitary system and I choose the control type to be "SETPOINT", I have to define some setpoint manager and honestly I did a copy and paste from the example file (5Zone_Unitary_VSDesuperheater) that I mentioned and I have no idea why I have to do this.

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Closed for the following reason duplicate question by Aaron Boranian
close date 2022-04-04 09:46:11.336873

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Duplicate of this post.

Aaron Boranian's avatar Aaron Boranian  ( 2022-04-04 09:46:28 -0500 )edit