This tab is displayed for all space templates (room, void, RA plenum and SA plenum). It specifies internal gains to the space (sometimes called casual gains).
The data displayed depends on the type of gain selected.
Gains can be specified in watts or W/m2. For people (occupancy), gains can be specified in watts or W/person, and the occupancy density can be specified in number of persons or m2/person. For lighting gains the power density can also be specified by the Installed Power density per 100lux (or per fc).
Internal Gain Parameters
Type
There are seven types of casual gain: Fluorescent lighting, Tungsten Lighting, Machinery, Miscellaneous, Cooking, Computers, People.
Clicking on the column header will allow the column to be sorted alphabetically or reverse alphabetically.
Reference
A verbal description of the gain. Clicking on the column header will allow the column to be sorted alphabetically or reverse alphabetically.
Input mode
This specifies the method by which the gain is defined. W/m2 or W for all gains other than People which is set a W/P or W. Lighting gains have the additional option of lux. Holes and windows added on a surface will reduce the floor area to be used in a W/m2 calculation. Using the W option can be used to bypass this procedure, specifically for high level zones where a floor may be set as 100% hole.
Maximum Illuminance
When lux is specified as the gain units, the maximum illuminance is specified in lux.
Installed Power Density
The W/m2/100lux figure used to specify a maximum sensible lighting gain and maximum power consumption in conjunction with maximum illuminance.
Maximum Sensible Gain
This is the value used to calculate the sensible heat gain per square metre of floor area for the casual gain type. Typical values can be found in CIBSE Guide A7. Clicking on the column header will allow the column to be sorted numerically or reverse numerically.
Maximum Latent Gain
This is the value used to calculate the latent heat gain per square metre of floor area for the casual gain type. Typical values can be found in CIBSE Guide A7. Clicking on the column header will allow the column to be sorted numerically or reverse numerically.
Occupant Density
This value is used to calculate the number of people per room. Clicking on the column header will allow the column to be sorted numerically or reverse numerically.
Maximum Power Consumption
This is the default peak rate of energy (or fuel) consumption of the device being described. Most casual gains (such as lights and small machines) consume energy (or fuel) as well as emitting heat. Clicking on the column header will allow the column to be sorted numerically or reverse numerically
Radiant Fraction
The proportion of sensible gain that is released as radiant heat (the remainder is assumed to be convective). Typical values are listed in CIBSE Guide A7. Clicking on the column header will allow the column to be sorted numerically or reverse numerically.
Meter
Where the gain has an associated energy consumption this parameter specifies the meter it uses.
Variation Profile
A profile governing the time variation of the heat gain.
Dimming Profile
This contains a control to set the modulating profile group reference that describes the dimming operation of the lighting gain throughout the year.
Diversity Factor
A multiple in the range (0,1) applied to the gain during simulations, and conditionally (depending on settings in the ASHRAE Loads dialog) during ASHRAE room and system loads analyses.
Ballast/driver fraction
This value is the fraction of the Maximum power consumption that that will be attributed to the ballast or LED driver for a lighting gain. The ballast or LED driver power consumption is constant irrespective of the dimming or variation profile of the lighting. The ballast or LED driver is also assumed to have the same radiant fraction as the lighting. A typical value for the ballast/driver fraction is 0.1 for fluorescent or LED lighting and 0.0 for incandescent bulbs or other light sources that do not have ballasts or LED drivers. The ballast/driver fraction parameter is ignored for compliance simulations but will be included in cooling loads runs (ASHRAE or CIBSE).
Allow gain to saturate for loads analysis?
When this box is ticked the maximum value of the gain will be eligible for ‘saturation’ during ASHRAE room and system loads analyses. Saturation means that the maximum value of the gain is delivered whenever the value of its profile is nonzero. Saturation will be implemented for eligible gains if it is specified by the Saturate gain profiles? settings in the ASHRAE Loads dialog.
Adding an Internal Gain
To add a casual gain click the Add/Edit button and the following window will appear:
This dialog lists all the gains that have been created in the project. To add a gain to a template, click on the appropriate cell in the Add To Template column so that a green tick appears. then click OK. The window will close and the casual gain will appear in the Casual Gains tab list. More than one gain can be added at a time by selecting the appropriate cells to display a green tick. The Select All and Deselect All buttons can be used to make this process easier.
