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[EnergyPlus_Support] Re: Problem with removing reheat coils in VAV

Hi,

In these days I have studied with careful the HVAC system I have to model in my thesis and for the problems I had with my file.

At this point I finally can mantain the zones' temperatures between 20-25ºC has I wanted. What I did was to remove some autosize fields and insert there the values I have in reality, and force the VAV damper to be always fully opened (which is the situation I have in reality). I also forced the system to insert in the zones the outdoor air I need.

The point that Dr. Li made about the internal loads made me understand better the problems I have. Both suggested programs were also useful, many thanks to you all!

I still have one big problem though. I'm currently using an Electric Heating Coil in each RTU, but I really need to use a Hot Water Coil and a Boiler. The problem is that when I switch from the electric to hot water coil the zones' temperatures drop below the setpoint and thermostat value (below 20ºC). More strange than that is that the setpoints are all the same, I only changed the coil type and add a hotwater loop and a boiler, but the outlet temperatures from the system drop a lot. If I rise the heating design temperature, the autosize feature increases the estimated heating coil capacity but the temperatures doesn't change at all... Do you know what's going on?

Note that this time I'm only using the HVACTemplates. To emulate the problem just open a example file with packagedVAV and just change the gas or electric heating coil for one with water.

If everything else fails (I'm running out of time), is there any known ratio between a electric coil's and a equivalent hot water coil's capacity? Like, for a same design heating temperature, a electric coil with x capacity is equivalent to a water coil with x/y capacity?

Once again many thanks to you all for all the precious help!





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