daylight savings support for WeeklySchedule

ibpsa / modelica-ibpsa

Modelica library for building and district energy systems developed within IBPSA Project 1

https://ibpsa.github.io/project1

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daylight savings support for WeeklySchedule #1904

Open Mathadon opened 4 months ago

Mathadon commented 4 months ago

For long simulations (longer than a few weeks), the local timezone may shift by one hour for daylight savings. We currently do not support that in the weekly schedule. Moreover, different regions perform the shift at different timestamps so we cannot hardcode the shift. My proposal would be to add optional support for this by adding a line in the config file like the two ones at the bottom:

# Comments start with a # 
mon:0:0:10          -  3   1  -
# Comments can be added in the table too 
tue,thu:20:30:59  123  -  45  -
wed                12  1   4  -
# users can set a timezone using a unix timestamp
1711877694         summertime
1730367294       wintertime

The switch would only work if the Modelica built in variable time is in the same range as the unix time stamp used since the weekly schedule does not know which year we are in.

Would it make sense to add this to IBPSA?

mwetter commented 4 months ago

A couple of comment:

It is called daylight saving time rather than summertime, so I suggest to change the keyword
It would be better to start with the keyword as then, if other keywords are added, parsing should be easier if it is key word followed by (as set of) values, rather than the other way around
Why unix time stamp rather than seconds since Jan 1, and then assume has periodicity of 1 year. I don't think many users are familiar with/deal regularly with unix time stamps.
Are these entries optional?
Daylight savings time is usually starting at 2am. Will this also work if a schedule starts at 1:30, e.g., it will pass "1:30" twice, once before and once after the change?

Mathadon commented 4 months ago

Thanks for the feedback:

Naming: The idea was to use 'wintertime' and 'summertime'. I'm not sure what the 'opposite' of 'daylightsavings' would be; 'nodaylightsavings'?
I think it would be better to start with the timestamp for all lines.
The number of seconds since January first would work too. I'd like to support both since we use time=unix time stamp.
The entries would indeed be optional.
The idea is that it should indeed pass 1:30 twice.

mwetter commented 4 months ago

@Mathadon : If it is not daylight savings time, it is standard time.