Heat demand in summer

[c0nb4]

Please describe the bug
Currently, there is heage demand in summer. Comparing with other 5R1C profiles, this is not the case there. I think it would be good to discuss options on how to fix this.

As disucssesd with @JoelSchoelzel there are several options to solve this.

1. Just accept it, as this is a model output and if the temperature falls below 20 degress, there will be heat demand if the building is set to 20 degrees.
2. Add a heating season, e.g. from April - October, where within a given temerpature range the heat demand is set to zero.

What are the steps to reproduce the bug?

1. Calculate any bulding and investiage the time series.

What behavior did you expect?
No heat demand in summer months, e.g. july.

[c0nb4]

@lensum I got an E-Mail about a third proposal, but I cannot see it here. Do you mind to repost it for discussion?

[lensum]

Sorry, I wasn't sure if it's a duplicate to the second option so I deleted it.
What I meant was the implementation of a heating limit temperature (Heizgrenztemperatur). It is usually set to something between 15°C and 18°C (iirc), and means that at temperatures equal or above that, heating is stopped. So it is similar to your second option, but would also stop the heating during the heating season (say, December), if the outside air temperature is sufficiently high.
What I don't currently remember is, if the heating limit temperature compares to some kind of floating average of the outside air temperature (because of the thermal mass of a building), or just the plain hourly temperature value.

[c0nb4]

Thanks! I think the idea is somewhat the same, but the implementation strategy might be a little bit different.

[JoelSchoelzel]

Hello everyone, thanks for your ideas! I'm still struggling a bit with taking such things into account when calculating the heating demand. When calculating the heat demand, a theoretical demand is determined first not considering the operation. The user then has the option of taking things like a heating period into account. That's why I would prefer the option that there is a selection option to set the heat demand in the heating period to zero.
What do you think?

[lensum]

Are internal and solar gains considered in the current heating demand calculation? Because this is usually the reason why a heating limit temperature is assumed: the argument is, that above 15°C the internal and solar gains are enough to keep a building at or above 20°C. So this is not specific to the operation of a heating supply, but affects the theoretical heating demand.

Maybe it could be implemented such that users can define a heating limit temperature and the default is equal to the currently assumed room temperature value? This way the default behaviour would be as it currently is and users would have a finer tuning possibility then a pre-specified range of months in which no heating occurs (irrespective of outside air temperatures).

My "problem" with a pre-specified heating period is, that it is possible to change the weather data to reflect a cold year and then the heat demand would still abruptly stop at a certain date instead of "fizzeling out". However, you are the developers and have the final say about that, just wanted to add my two cents to the discussion.

[c0nb4]

I support the argument by @lensum.

I think default heating limit temperature set to assumed room temeprature value sounds good. However, how to decide the appropiate method of calculation?

In https://de.wikipedia.org/wiki/Heizperiode there are several methods proposed for calculation. I'm happy to do a PR, but it would be great to agree on a methodology first.

[lensum]

A little bit about the heating limit temperature (if you want to go with this approach) is described in this book: https://doi.org/10.1007/978-3-658-38274-2_6 (p. 257-258). Unfortunately, it is only available in german.

By the way, while implementing such a heating limit temperature in a hacky way in my fork, I noticed that there already is a parameter T_heatlimit in the design_building_data.json file, though it seems to be intended for heat pump design.

[lensum]

By the way, while implementing such a heating limit temperature in a hacky way in my fork, I noticed that there already is a parameter T_heatlimit in the design_building_data.json file, though it seems to be intended for heat pump design.

Just noticed that the parameter was deleted in a later version.