Open emanuel030 opened 4 years ago
@emanuel030
Since it is a calculation which can only be performed after the loads (all 8760 hours, all buildings) have been defined,
would it not make sense to calculate that after the demand script? before it get's used? I think it could either be
@daren-thomas From my knowledge the capacity from the total_demand file is only used in system_costs. So it would be sufficient to include it in the system_costs module, however you need all hourly values (so the individual building files B1001, B1002 etc. ) from the demand which would need to be imported there.
@emanuel030 , i think this will be a great addition!
it can be generated in the same loop while generating Total_demand.csv
but you will need to create a separate file to save hourly values (smth like District_diversity_factors.csv
?)
The coincident peak demand (= coincident capacity) is actually 1 single value for the entire district (over all building, over the entire year). Same with the diversity factor which is diversity_factor = ((non_coincident_capacity- coincident_capacity)/non_coincident_capacity). To calculate the coincident capacity you take the maximum of the joint cooling load curve of all buildings in the district (hourly resolution). Since all results are stored per building though I thought it would make most sense to first calculate coincident capacity for the entire district and then split it up between the buildings relative to their non_coincident_capacity.
District cooling&heating systems have the advantage of a coincident capacity for the entire district, which is calculated by taking the maximum of the sum of loads. Right now the capacity is defined as the sum of the individual maxima building loads, no matter which technology is chosen. The difference between the those two capacities is defined as the diversity factor and can be in the range of a couple of percent, up to 30-40% (District Cooling Theory and Practice, Alaa A. Olama 2017) High diversity factors are expected for mixed use districts.
Here the code of how it is calculated and also an example case:
To consider the coincident capacity is important since it can highly influence the system costs (system_costs module). The diversity factor also offers additional information on the system.
Since it is a calculation which can only be performed after the loads (all 8760 hours, all buildings) have been defined, one approach to incorporate this would be to output the coincident capacity as an additional column in the total demand or to overwrite the 'QC_sys0_kW' for the buildings which have a district scale cooling/heating. The capacity (for district system) could be split up over the buildings according to the scale of QC_sys_0kW.
Please let me know if there is someone with spare time to implement this in a proper CEA manner. I have started implementing this in branch 'centralized_capacity_efficiency' but it is makeshift, implemented in an unfitting module and also only for cooling.