Thermal Zone Settings¶
When a zone template is first assigned to a zone object (brep), hundreds of zone settings are assigned to the zone based on the template. All zone information can be reviewed and edited by selecting the edit button in the thermal model object table.
The Zone Settings panel is organized into six tabs: Loads, HVAC, Ventilation, Water, Material and Settings.
Under this tab, the internal loads of a zone are specified due to people, equipment and electric lighting. The user should make sure that the numbers selected for a given zone constitute a meaningful approximation of how a modeled space is being used or will most likely be used in the case of a design model. For each internal load type, there is a peak load (density) normalized by floor area that indicates the heat added to a space at maximum occupancy or when all equipment and lighting is being switched on. Each internal load is further described by a schedule that consists of 8760 values for each hour of the year between zero and one. The figure below shows the Schedules Editor with the default occupancy schedule for a medium office. The top figure shows the hourly schedule for the first day of the year. The lower figure shows the schedule for all hours in the year. Clearly visible is the high occupancy on weekdays from 8am to 6pm, with a lunch period from noon until 2pm. A schedule value of 0.5 at 1pm on weekdays shows that half of the occupants are at lunch at that time. Between the weekdays, the weekends with markedly lower occupancy are clearly visible.
Schedules that come with the ClimateStudio library are locked. To modify a schedule, create a copy and rename it. Select the edit icon to modify the new schedule (see image below).
As shown below, year schedules can be edited in two ways:
Based on individual days that can then be assigned to any particular day in the year or to all weekdays/weekends, etc. Same as for annual schedules, to modify a day schedule, create a copy of an existing day schedule and modify the 24 hours values for the day as needed.
Another option is to import a custom series of 8760 values from the clipboard.
Carbon And Cost Factors
Under the settings tab the user can specify carbon and cost factors for heating, cooling, hot water use and electricity. These conversion factors are then used to translate the different loads into equivalent carbon emissions or energy costs. For example, an electricity price of 0.106 $/kWh corresponds to the 2019 average US retail price for electricity. At the same time, the approximate US retail price for natural gas was 0.04 $/kWh. The ClimateStudio default values for electricity (cooling and electricity) of 0.612 CO2e kg/kWh correspond to the 2017 average value for the US grid. It is worth pointing out that these numbers are highly variable both over time and regionally. Up to date numbers for different US zip codes are provided by the Energy Protection Agency’s Power Profiler https://www.epa.gov/energy/power-profiler#/.