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RWTH-EBC / BESMod

A Modelica library providing building energy system modules
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Allow muliplier for DHW-profiles #71

Open tstorek opened 9 months ago

tstorek commented 9 months ago

What is the problem?

There is no clear way to implement domestic hot water profiles for multi-family homes without implementing a new ProfileRecord that includes e.g., a multiplier for the mass_flow_rate according to https://www.waermepumpe.de/fileadmin/user_upload/waermepumpe/07_Publikationen/BWP_LF_TWW_2019_Druckvorlage_neu.pdf

How do we want to solve it? Describe the solution you'd like

Although not quite realistic in the dynamics. For dimensioning the DHW-Storage for multi-family homes, using a multiplier is a common approach. (https://www.waermepumpe.de/fileadmin/user_upload/waermepumpe/07_Publikationen/BWP_LF_TWW_2019_Druckvorlage_neu.pdf) I tested it by adjusting the model and introducing a scaling factor for the m_flow. Accordingly, m_flow_nominal changes and lead to a larger QDHW_flow_nominal. Also, multiplying VDHWDay and QCrit should finally lead to properly sizing the DHW-Storage.

Describe alternatives you've considered

Alternatively, one could implement additional DHW-"comfort"-Profiles like XL and XXL. However, they may cover one or two more cases but need to be more flexible in scaling for more dwellings.

Additional context

I tried the solution, and it worked. However, my entire Project is currently on an older version, and I cannot estimate if the solution meets the current requirement. So, I'd like you to please take this as a suggestion. Keep on going. BESMod seems to have become a valuable tool already :)

FWuellhorst commented 9 months ago

@tstorek : Thanks for the suggestion! Besides having DHWCalc, this would be a valuable addition. I think I won't add it myself, as I am not familiar with multi family dwellings and don't know about the critical periods, simultaneity factors, etc. and if they all scale linear. Maybe @larissakuehn knows what a good default / simplified approach would be?

tstorek commented 9 months ago

@FWuellhorst well this only for dimensioning and according to the mentioned guideline without any second thoughts. Simultaneity factors are not considered as the worst case scenario will be assumed. Sure this will most likely lead to oversizing of the storage in real world scenarios, but apparently it is a common approach. As I understand the load-profiles are anyway only an artifical approach to the problem and actually only suited for perfromance evaluation but are far of actual operation scenrios.

FWuellhorst commented 9 months ago

Ah, I missed the point that it is about sizing only. If you have your solution at hand, could you push it in a branch? I can integrate it once #31 is merged. Thanks :)