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pv panels and solar collector in openstudio

asked 2019-04-11 00:23:37 -0500

Mocarquer's avatar

updated 2019-04-11 07:30:58 -0500

Hi, I am making a comparison between two models for a Chilean house. One with hvac split converter for hvac and water heater by natural gas without solar collector and the other with solar collector flat plate for water heater and the same hvac model, but with pv panels with the Add Rooftop PV measure. I am new in openstudio and I don't know the difference between the two models, or the difference is very little among them. If someone could help me, it would be of great value to me. If someone wants me to send you the model here is my email:

I can't upload photos.

                             Case one [GJ]                        Case two [GJ] 
                     (with pv and solar collector)      (no pv and solar collector)
Total Site Energy           37.72                                 40.05
Net Site Energy            -22.0                                  40.05
Total Source Energy         77.68                                 80.80
Net Source Energy          -111.3                                  80.80


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answered 2019-04-11 07:31:29 -0500

@Mocarquer I would argue that there are reasonable differences between the summary reports of the two models that are not very little.

  • Case 1 has less total site energy. This is because of the solar plate collectors providing hot water to the water heater, which reduces the amount of energy used at the site (aka the building itself).
  • Because the water heater uses natural gas, the difference in total site energy results in an almost equal difference in total source energy. This is because the default site-to-source conversion factor for natural gas is 1.084 (see below). These conversion factors can be set by the user using FuelFactors objects.

image description

  • Case 1 has negative Net Site Energy, while Case 2 has the same value for both Net Site Energy and Total Site Energy. This is because of the PV panels in Case 1 reducing the amount of electricity the building requires from the grid or utility. The negative value indicates that the PV panels are generating more electricity than the building consumes.
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Last updated: Apr 11 '19