EnergyPlus how to model simultaneous heating and cooling heat pumps

asked 2015-10-21 02:50:09 -0500

J gravatar image

updated 2015-10-21 14:57:33 -0500

Does anyone have a recommendation on how to model in EnergyPlus simultaneous heating and cooling heat pumps?

Schematic with Screw Compressors - Scroll Compressors will be considered as well in my project: Typical SHCHP Schematic

This is a central plant system that provides hot and cold water to four-pipe units throughout the building by exchanging heat between the hot and cold water loops and the exterior air. It is very similar to the way the CentralHeatPumpSystem object works but rather than the water loop running through a ground loop HEX the refrigerant in the heat pump exchanges energy with the air to add or subtract heat.

From a manufacturers description of the operations: "These units can produce hot and chilled water at the same time and totally independently, adapting to the variable requests inside the building. There are three basic operating configurations which are totally independent from external temperature conditions: - only chilled water production (the unit works as a simple chiller); - only hot water production (the unit works as an heat pump); - combined production of hot and chilled water (the unit produces simultaneously and autonomously cold and hot water for the two plant’s sections)."

I think I need to model the way the heat is added to/rejected from the refrigerant rather than the water loops like if I tried to use the central heat pump system but if someone else has an approach or suggestions I'd appreciate hearing about it.

How the performance varies with seasonal demands for heating/cooling in the building:

Typical SHCHP Performance

Thank you.

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(That's a Climaveneta unit isn't it? I think I recognize the style of the first schematic you posted.) Could you maybe use CentralHeatPumpSystem and use a fluidcooler as the condenser, but set the power to none, including the pumps? It's fishy at best though...

The other thing I can think of is to define your own PlantComponent:UserDefined but that seems pretty intimidating...

Julien Marrec gravatar image Julien Marrec  ( 2015-10-21 15:16:33 -0500 )edit

Yes it is a Climaveneta unit but I won't be selecting the equipment and may end up modeling several suppliers units. The CentralHeatPumpSystem and PlantComponent:UserDefined are the options I'd looked at but you are right in that I'm intimidated by the UserDefined. I hadn't thought of using a fluidcooler on the condenser loop have to sketch that idea out and see how it might work. Thanks for the idea.

J gravatar image J  ( 2015-10-21 15:33:46 -0500 )edit

I have to model the same system. Did you manage to model it? Any recommendations?

Santiago Velez gravatar image Santiago Velez  ( 2016-01-03 16:51:41 -0500 )edit

I also have to model this exact type of system, any advice I can get would be great. Perhaps a new EnergyPlus feature would ease the modelling process? Thanks

IST_Vasco gravatar image IST_Vasco  ( 2018-08-09 06:18:14 -0500 )edit