ASHRAE Loads

ASHRAE loads now includes flexible user control settings, which can be independently configured for Room & Zone Loads and System Loads. The new functionality is detailed in the following sections.

 

ASHARE loads now allows the user to include/exclude internal gains from a heating loads run, see Figure 2-1 .  By default, the internal gains are not included for either the Room & Zone heating loads or the System heating loads.

 

Figure 2 - 1 : ASHRAE Room & Zone Loads dialog with the option to include internal gains for the heating loads engaged

 

Once internal gains are included (optional for heating loads, always included for cooling loads) then the user has the ability to set saturation conditions for these gains.  Here we will discuss the ability to saturate internal gains both for heating and cooling loads runs.

Figure 2 - 2 : ASHRAE Room & Zone Loads dialog with the option to saturate internal gains profiles for peak heating and cooling loads

 

The following options are available:

·       No

This leaves all internal gain profiles unchanged (default for both Room & Zone and System Loads for heating and cooling runs)

 

·       Yes

This interprets all internal gain profile values that are greater than zero as being equal to 1.0 (100%) during sizing runs. However, this only occurs if the appropriate setting has been engaged in the internal gain either through building template manager or via space data, see Figure 2-3 . The ‘Allow profiles to saturate for loads analysis?’ is checked by default.

 

·       During system occupied hours

This option increases non-zero internal gain profile values to 100% just during System Occupied Hours thus avoiding any increase of non-zero values maintained outside of those hours. The system occupied hours are generated from the data entered for the system (HVAC network) on the Schedules tab of the System Parameters dialog.

 

 

Figure 2 - 3 : Internal gains dialog, accessed from the Building Template Manager, with the option to allow profile saturation for loads analysis engaged

 

 

If internal gains are included in the loads analysis, then the user has the ability to include/exclude diversity factors as setup for each gain in either building template manager or Space Data as shown in Figure 2-4 .

Figure 2 - 4 : Internal gains dialog, accessed from the Building Template Manager, with the Diversity factor set to 0.8 for the selected lighting gain

 

This option is available for both heating and cooling loads calculations.  By default, diversity factors are excluded for Room & Zone Loads and included for System Loads.

Figure 2 - 5 : ASHRAE Room & Zone Loads dialog with the Diversity Factors not applied to internal gains

 

 

In ApachePro, two new day types have been added to allow for the definition of specific heating and cooling design day profiles.

Figure 2 - 6 : Sample heating & cooling design day profiles shown as part of a weekly profile in ApPro

 

 

These design day profiles are the default reference in the Room & Zone loads and System Loads dialogs.  By unchecking the “Default” box in the loads dialog for heating and/or cooling loads, users can select a day of the week for use in load calculation runs in place of the design day profiles if desired.

 

Figure 2 - 7 : ASHRAE Room & Zone Loads dialog with the default selection of heating & cooling design day profiles shown