When you sellect a system and a zone combination, you need to consider how you wanted to control the system.
For example, you have two zones, one thermostat, and one fan, cooling coil and compressor unit (AHU for cooling only). You sense the temperature in one zone and control either the fan and/or the compressor.
If you control the fan, the compresor must shut off by itself on some limiting condition. You can turn off the compressor, and leave the fan running. (The constant fan mode.) You can turn on and off both the fan and the compressor by the thermostat. These choices are made by you on setting up the schedules.
When this control is activated, the other zone can only slave to the controlled zone. Therefore, you try to balance the air flow to the two zones by fixed dampers. The fixed damper is the Direct Air unit in the zones. No additional control is available to the second slave zone.
If you wanted to use adjustable damper in the zones, you need two thermostats, one for each damper.
AirTerminal:SingleDuctLVAV is a variable air volume damper. When you have associated the thermostat to these units, what do you do with the Fan and compressor?
There is no EPlus control object to look at the two VAV damper setting and to adjust the AHU fan or compressor. However, there is by-pass damper which you may use to shunt of the air not required by the zone back to the input of the AHU.
This by-pass principle can be applied to air loop or the water loop with pumps in the plant.
When you are choosing the different models, you must look at the controls you are using.
Boilers and chillers are generally not controlled by the zone thermostat. Therefore, if you try to connect a boiler directly to a coil in the zone, you may have problem in controlling the boiler.
The solution is to have a fan coil unit in the zone controlled by the thermostat, and let the boiler control itself by the water setpoint temperature. You watch the boiler temperature and the PLR of the zone coil to verify the system performance.
I am not sure how you will be using the water to air heat-pump. If you have a workable real system, you will probably fine a simulation model to match. Computer controlled real system cannot be simulated easily with EPlus.
Dr. Li
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: chuck_carpenter99@xxxxxxxxxxx
Date: Sat, 20 Jun 2009 02:27:49 +0000
Subject: [EnergyPlus_Support] AirLoopHVAC:UnitaryHeatPump:WaterToAir and VAV
I'm interested in modeling a GroundHeatExchanger
Page 1002 of the e+ InputOutput document seems to suggest that only direct air terminals can be used with AirLoopHVAC:
Does anyone know if such a VAV design exists in e+ or if its even possible?
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