Negative equipment loads in supermarkets

hello all,
im trying to simulate a supermarket and therefore i have a negative equipment load. There are several cooling devices (fridges, etc) which are cooling down the zone in an enormous dimension. So i put the equipment load to a negative value (-110 W/m2). The Honeybee can’t handle the negative value. Is there any other way to handle the negative HeatingLoads in my zone?

regarding forward to the discussion

I think there might be some.misunderstanding with regards to what equipment load means here. For Honeybee (through EnergyPlus) the equipment load corresponds to the energy consumption of the equipment in the space. Your cooling devices emit negative heating energy but the equipment load from these components is positive as they are consuming energy to produce negative heat.

Does this make sense?


Thanks for the quick reply. Yes this makes sense, there is a difference between the electric and the thermal loads. I thought the loads put in the zone loads are also calculated as thermal loads.E.g. electric loads as lighting heat up the zone. In the case of light you can calculate them 1:1. 1W electric load means 1W thermal load. This is why i thought to put the negative heating loads also in the zone loads. Where should i put them instead?

@Norbert ,

As @antionedao states, I think this really comes down to how you imagine the refrigerators in the supermarket running. Most home refrigerators reject their heat to the room in which they sit, meaning that you should just be modeling them as electric equipment with a wattage equal to the electricity used by the fridge. I think several models of supermarket refrigerators also work this way but, if you have something like a walk-in freezer that rejects heat to the outdoors, you probably want to model this as a separate zone with its own cooling system and set points.

I know that the OpenStudio interface also has a whole tab under the HVAC section for adding refrigeration systems so this might be of help depending on how detailed of a refrigeration model you want to create:

Thanks a lot - never worked with Open Studio. Just modeled my Supermarket in ArchiCAD, Rhino and Grasshopper. I’ll take look how to implement the data in Open Studio. It’s worth a try!