Use a triggered subsystem to generate the desired signal. The trigger signal is based on time.
Assuming that the time signal is in hours, then
day = floor(time/24); % this is the day of the year
dayofweek = mod(day,7)+1; % this is the day of the week (1 through 7)
hour = floor(time); % this drops fractions of an hour and is the hour of the year
hourofday = mod(hour,24)+1; % This is the hour of the day (1 to 24)
The output of the "Day of Week" block is:
dayofweek < 6
This is "true" for days 1 through 5.
The output of the "hour of day" block is:
hourofday >= 8 && hourofday <= 16
These two signals are combined with an "And" block, which produces a "true" signal when the day of week is 1 through 5, and the hour of day if between 8 and 16. This signal is used to turn on the "Signal" block which is your internal daytime heat load.
