Ground floor Properties

The Properties For: Ground floor dialog opens when the Tree hierarchy: ...SurfacesGround floor Project Tree object´s pop-up menu is activated in the OpenBuildings Energy Simulator Project Tree dialog and the Properties menu item is selected.

It contains controls used to view and define properties for ground floor surface types. Ground floor surfaces are floors inside rooms that are exposed to the outside of the building, directly in contact with the ground or exposed to the outside air (above a crawl space for instance). The ground floor contains properties that all surface sub-types share as well as properties specific to the ground floor sub-type.

Note: The Ground floor Construction details properties panels under the Construction details heading contain controls used to view the selected ground floor construction details. The properties displayed here are saved in the OpenBuildings Energy Simulator materials database’s constructions definitions. Constructions can be viewed, manipulated and created using controls and settings found on the Materials Manager.

Property heading	Properties
Category	Displays the surface category. Category is a read only property.
Sub type	Used to view or change the surface Sub type from Ground floor to another floor sub-type. The Sub type drop-down list is filtered and contains only floor sub types.
Name	Used to enter a name for the ground floor. The name entered here appears appended to the ground floor object on the project tree dialog.
Construction	Used to view of change the ground floor material construction definition.
Dimensions	Displays overall dimensions of the selected ground floor. Length — Disabled for the ground floor sub-type. Width — Disabled for the ground floor sub-type. Height — Disabled for the ground floor sub-type. Area — Displays the total area of the selected ground floor. Volume — Disabled for the ground floor sub-type. Orientation — Displays the orientation of the ground floor relative to the building orientation. Building orientation is defined in the Building Properties dialog.
Heatflow	Contains controls used to view and set Heatflow data for the ground floor. Heatflow refers to the energy transfer occurring through a surface’s material construction. Heatflow is established automatically as rooms are created. OpenBuildings Energy Simulator determines if the adjacent space below the room floor is in contact with another room below. If no adjacent room is found under the floor, the surface is defined as being of the surface sub-type ground floor. Type — Used to display and modify the nature of the heatflow occurring through the ground floor. None – When selected, the surface is considered to have no energy transferred through it. For instance, when the surface is a virtual wall. This is almost never selected for a ground floor sub-type. Specified Temperature – When selected, heatflow through the ground floor will be calculated based on the values entered for winter and summer temperatures in the two available temperature options. The temperature options are only visible when the heatflow type is set to Specified Temperature. Winter temperature – Specifies the winter temperature outside the ground floor. Summer temperature – Specifies the winter temperature outside the ground floor. Room Type – When selected, heatflow through the ground floor is calculated based on the standard room type of its parent room. Room type – Lists the room types available for the project. Adjacent Room – When selected, the heatflow through the surface is calculated by the conditions in the Adjacent Room. Adjacent room – This option is not selectable due to the ground floor being of the surface sub-type ground floor. Heatflow can not be calculated using this option. Ground – Ground is the default heatflow type for ground floors. When selected, the heatflow through the ground floor is transferred from contact with the ground. Energy from the ground depends on factors such as the ground temperature which depend upon the project site’s location, the weather profile, and the local topography and soil type. External – When selected, the heatflow through the ground floor is transferred from the conditions outside the building. Energy from the environment outside the building depends factors such as the weather profile and external shading.
Common	Displays common construction details for all surface sub-types. Common construction details are read only properties. Category — Displays the construction category associated with the surface. Total thickness — Displays the surface total thickness which included all the material layers (solids and air gaps) that make up the construction. Decrement factor (internal) — Displays a Decrement factor associated with the construction’s inside surface. The Decrement factor is used to calculated the amount a thermal wave is decreased in intensity during its propagation process from the outside to the inside of the surface construction. Decrement factor (external) — Displays a Decrement factor associated with the construction’s exterior surface. The Decrement factor is used to calculated the amount a thermal wave is decreased in intensity during its propagation process from the outside to the inside of the surface construction. Fixed thermal properties — Used to display the surface construction setting related to its thermal properties which are defined in the Materials Manager dialog. When on, calculated surface emissivity and absorption coefficients are overridden, enabling you to define your own thermal properties (in the Materials Manager dialog). When off, the calculated transmission values are used. Admittance (internal) — Displays the amount of heat that passes through a unit area of the constructions’s inside surface, when its external face is subject to a unit temperature change. Admittance (external) — Displays the amount of heat that passes through a unit area of the constructions’s external surface, when its inside face is subject to a unit temperature change. Time lag (internal) — Displays the time it takes for heat generated by the sun to transfer from the outside, through the construction, to the inside surface of the construction into the building envelope, and affect the internal conditions. Time lag (external) — Displays the time it takes for heat lost to transfer from the inside, through the construction, to the external surface of the construction from the building envelope. Weight (internal) — Displays the construction inside surface’s weight per unit area. Weight (external) — Displays the construction external surface’s weight per unit area.
External surface	Contains controls used to display thermal transfer properties for external surface types such as the ground floor. External surface construction details are read only properties. External surface construction details are defined using the controls on Materials Manager. Surface emissivity — Displays the construction surface emissivity factor. Surface emissivity is a measure of the efficiency in which a surface emits thermal energy. It is defined as the fraction of energy being emitted relative to that emitted by a thermally black surface (a black body). A black body is a material that is a perfect emitter of heat energy and has an emissivity value of 1. A material with an emissivity value of 0 would be considered a perfect thermal mirror. Absorption coefficient — Displays the absorption coefficient for the construction's external surface. The absorption coefficient is a number between 0 and 1. The lower a construction's external surface solar absorption coefficient, the less solar heat it transmits. Upward-U-Value — Displays the calculated outside surface U-value or thermal transmittance of energy traveling upward through the selected construction. Downward-U-Value — Displays the calculated outside surface U-value or thermal transmittance of energy traveling downward through the selected construction. Horizontal-U-Value — Displays the calculated outside surface U-value or thermal transmittance of energy traveling horizontally through the selected construction.
Ground floor	Contains controls used to display insulation and ventilation properties for the Ground floor surface type. Ground floor Construction details properties are read only properties. Ground floor Construction details are defined using the controls on Materials Manager dialog. Insulation type — Displays the insulation type used for the ground floor. Insulation thickness — Displays the insulation thickness used for the ground floor. Insulation width — Displays the total insulation width used for the ground floor. Insulation material — Used to display the insulation material used for the ground floor. By default, the material drop-down list contains a single insulation material. This is a filtered display, which is also read only. To change the insulation material, use the Defaults Manager dialog to change the default ground floor construction definition, or the Room Type Manager dialog to define ground floor constructions using other insulating materials for different room types. Underfloor space height — For ground floors with an outside air space below. Displays the height above the solid ground to the underside of the exposed floor. Ventilation opening area — Displays the total area of ventilation openings in the selected construction.
Layers	Contains controls used to display the surface’s construction material layers in a read only table. The table displays thermal properties for each layer such as the thickness, density, conductivity, specific heat and vapor resistivity.