I created a housing geometry in DF. After validating the heating, cooling and hot water demand with benchmarks, I want to increase the number of houses and arrange them along a grid pattern. But when I increase the number of houses in my model the Tab water values suddenly change. Here is an example script with purple giving the OS result of 1 house and blue giving the result of 3 houses.
I checked if it was a problem with adjustments I made in the default tap water flow rate, or a problem with open-studio (by comparing the results with E+) but the changing values only seem to occur when multiplying the geometry.
This room appears to be the same size as the one in your “not multiplied” model. So more hot water demand in the same size room means that this room is going to get colder in the multiplied model compared to the not-multiplied model. This is because the heat pump water heater pulls more heat from the room to make the hot water. A colder room means that the heat pump runs less efficiently, resulting in more energy use per square foot of floor area in the multiplied model.
Thank you for your explanation! This makes sense. Is there a way of also assigning the SHW to every unit you multiply, as opposed to the 1 SHW system now supplying every room of the multiple geometries? In the final model, I have to scale up to 180 geometries, and the aim is to keep the hot water demand at the given benchmark.
Or is this unavoidable when multiplying geometries?
Yes. Just graft the inputs to the HB SHW System component and do some data tree matching to make sure that you’re assigning one SHW system for each of the multiples of the Buildings that you are simulating.
Note that you can also just do this assignment in Dragonfly with the DF SHW System component. This might be easier since you would have less data tree management to do.
Thanks for the reply. Since I don’t have a lot of experience with data tree management I followed your suggestion of working with the DF SHW component instead. However, this resulted in the following errors:
