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HVAC Template for standard Split AC

asked 2014-12-07 00:49:48 -0600

Xandrika's avatar

updated 2015-07-11 17:10:29 -0600

I studied in detail different HVAC templates of Openstudio and Energyplus but, unfortunately, I did not find the correct one for my situation. I would like to model a common split HVAC (for one room) with DX cooling and electric heating (no heatpump!) (size: 0.75-1.0 tons). I found Openstudio PTAC Template but it has Hot Water Heating and I cannot change it. In Energyplus PTAC Template, I saw that I can specify Heating coil to electric.

So, is there any template for my desired system in Openstudio? Which one? If not, could you, please, specify the components and layout of such a system in OS HVAC System tab (if possible with screenshot. Thanks a lot.

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Do you need the fan to cycle with the coils?

Kyle Benne's avatar Kyle Benne  ( 2014-12-07 09:12:21 -0600 )edit

this type of split AC.

Xandrika's avatar Xandrika  ( 2014-12-13 04:46:00 -0600 )edit

2 Answers

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answered 2014-12-14 20:40:17 -0600

I'm guessing that the fan needs to cycle on and off with coil. Your options to support that are to use one of the zone HVAC systems (like PTAC) or use an AirLoopHVAC based system with a AirLoopHVACUnitary component inside of it to manage the cycling. OpenStudio does not support reconfiguring zone equipment graphically in the application, therefore you cannot graphically replace the water coil with an electric heating coil. Certainly this is possible with a measure but I'm going to assume that you would rather use the UI. So go the AirLoopHVAC route following these steps to build up a system from components.

Create a new empty AirLoopHVAC system.

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Add an oa system.

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Add an AirLoopHVACUnitarySystem. You want the one with DX cooling, cycling, and electric "reheat", which will really just be heat in this case.

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Attach your zone.

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Add an uncontrolled terminal.

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Edit the unitary system and make sure that the attached zone is specified as the Controlling Zone.

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Thanks, @Kyle Benne. As I understood the rated COP is the values that define efficiency of the system. I/O reference says that: The gross COP should NOT account for the supply air fan. However, in South Asia manufactures use more the EER and the Indian Star Labeling as efficiency indicator. Is there a way to convert EER into COP? If so, HOW?

Xandrika's avatar Xandrika  ( 2014-12-14 23:48:55 -0600 )edit

@Xandrikathis answer might be helpful in answering your question about EER to COP.

aparker's avatar aparker  ( 2014-12-15 09:10:49 -0600 )edit

answered 2014-12-15 08:58:57 -0600

EnergyPlus HVACTemplate:System:Unitary and HVACTemplate:System:UnitarySystem both can be used to model a split system or a rooftop system. HVACTemplate:Zone:PTAC is intended for a non-split through-the-wall type of system, but it can also be used. All three of these systems model essentially the same set of components and can apply to split systems or rooftop systems given appropriate efficiency and fan pressure inputs.

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Asked: 2014-12-07 00:49:48 -0600

Seen: 3,213 times

Last updated: Dec 15 '14