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[EnergyPlus_Support] Re: Multiple HVACTemplates Per Zone Error
The issue right now is that the zones are controlled by two separate systems. The fancoils are controlled by an old pneumatic Honey Well system whereas one constant volume air handler feeds the basement and two multizone air handlers control the first and second floor. All the controlled by modern electronic controls. We have room thermostats for each of the fan coils but a few temperature sensors for the air handlers.
What I wanted to originally was to use the HVAC Template to "lay out" the nodes and then work thru the expidf to more accurately represent the system as it operates. I am tentatively planning on not modeling the switch over losses and just subtracting the energy loss from our metered energy consumption for baseline energy consumption.
Anyway, in attempting to set up the HVACTemplate:System for the air handlers and the HVACTemplate:Zone for the fancoils and the VAV (just to get the nodes set up properly) with extra thermostats. I got the error that says "ZONE NAME". Names must be unique across all HVACTemplate:Zone: objects. Because of this I am assuming that I can't use the HVACTemplate to "set up the nodes" and then swap out objects keeping the nodes there.
What I then did was I made an HVACTemplate for the VAV feeding the zones with thermostats. I then took the expidf and put in two AirTerminal:DualDuct:Constant Volume for the MZ air handlers then replaced AirTerminal:SingleDuct:VAV:NoReheat but I put in a constant volume fan and set the min/max airflow to being the same. Would the AirTerminal:SingleDuct:Uncontrolled be a good replacement for this? Would I then remove the zone equipment if I did that?
I then took the HVACTemplate:Zone:Fancoil expidf and began copying and pasting the relevant objects from that expidf to the Air Handler idf and adjusted the branches. I haven't gotten it working yet but I am looking for guidance on if this makes sense and whether or not I can get two HVACTemplate:Zone... to the same zone using the HVACTemplate objects instead of the longer way.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, YuanLu Li <yli006@...> wrote:
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> You have a two pipe fan coil unit in each zone. This is a zone unit, and does not need an AHU. The OA mixer may be included in the unit. You need two water plants, one for HW and one for ChW. EPlus does not switch plant loops, so you will connect them as a four pipe system. In Summer, the chiller is turned on. In Winter the boiler is turned on. The change over days are assigned by you with a schedule.
> How much energy are wasting? I think, you are referring to the days that the system is on and the fan coil units are not running. In Eplus, the plant would be turned off when there is no demand. EPlus does not simulate pipe loss (all specified as adiabatic). The tank, if used, may have a conduction loss to the environment. Therefore the annual simulation would not give you the idle energy wasting values. In a real system, you will observe the PLR when idle, and use that to estimate the energy usage. For example the chiller may cycle between 12.5 and 7.5°C. Start at 12.5°C run till the water is at 7.5°C and then turn off. The energy wastage is entirely on the tank and pipes, and the power is for the pump and the fan at the EIR. These cannot be easily simulated, because the location and environment for these pipes are not known. You may simulate the effect with an equivalent storage tank. The plant will keep this tank at the designed water loop temperature when the demand is zero. The direct answer to you question on the EPlus template usage is that the set of templates must be for the appropriate application.. You will use the HVACtemplate:Zone: for the fan coil unit. and the HVACtemplate:plant for the water plant, boiler and chiller. VAV for the zone is an adjustable damper for an air duct, which is to be used with a HVACtemplate:system. (two templates) to form the DOAS (AHU system). An additional fan coil unit in the zone is still possible, but not easy to specify, because one zone thermostat cannot control two sets of equipment.. You can only specify one HVACtemplate:Thermostat for each zone.
> Dr. Li
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: matthew.sverre.anderson@...
> Date: Tue, 7 Aug 2012 22:04:32 +0000
> Subject: [EnergyPlus_Support] Multiple HVACTemplates Per Zone Error
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> Hey Everybody,
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> So I have a system that has central handlers feeding 5 zones, 1 basement, 2 north/south for the 1st and 2nd floor. It then has a room fancoil system that heat/cools the same zones. The fancoil system is two pipe with a switch over where we can only heat or cool at any given time.
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> I would like to get to the point where I can correctly model the amount of energy we are wasting in switch overs, I have done this in excel already but I would like to figure this out in E+.
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> In trying to put both a fan coil and a VAV air handler into a zone I received an error regarding the DSOA systems where it is trying to tell me I can't have more than one HVAC Template per system. Is this true?
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> Any work arounds here?
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