Space Conditions

This tab is displayed for rooms and plenums. It contains space attributes relating to space conditioning and two parameters relating to space modelling.

 

     Space Conditions tab data for a room wth ApSys methodology

(For a room with ApHVAC methodology the ‘Plant (auxiliary energy)’ frame is absent. For plenums only the ‘Model settings’ frame is present.)

 

In ApacheSim and System Loads analyses, the control parameters entered here will be overridden in any spaces that feature in an attached ApacheHVAC system.

Parameters labelled in blue are autosized parameters calculated by the room loads analysis program. Buttons in the ASHRAE Loads and CIBSE Loads (ApacheCalc) dialogs allow these parameters to be re-zeroed or set back to the values they had before the last loads analysis.

 

Parameters in this frame are defined for rooms, and used for room and system load calculations. For rooms with ApSys methodology they are also used for simulations when there is no attached ApacheHVAC system.

A modulating profile scheduling the operation of the heating plant. Heating will be available when the modulating profile value exceeds 0.5. Profiles are created and edited in ApPro, the Profiles Database Manager.

This parameter is overridden if the space is modelled in ApacheHVAC.

The temperature set point for heating control. This value must be less than or equal to the Cooling Set Point at all times. The Heating Set Point can be constant or it can follow an absolute profile.

This parameter is overridden if the space is modelled in ApacheHVAC.

These parameters specify the demand for domestic hot water.

This specifies the procedure for determining the how the space’s DHW demand varies with time.  The demand can be linked to space occupancy (as set in the Internal Gains tab) or governed by an independent profile.

When DHW Consumption Pattern is set to ‘Independent Profile’ this option specifies which profile is to be used to modulate the DHW demand.

DHW consumption

The maximum rate of hot water consumption. The unit is litres per hour per person or litres per hour (or equivalent IP units) depending on the specified Consumption pattern.

Hot water consumption is accounted for in ApacheSim, and optionally in ASHRAE Loads and CIBSE Loads.

Parameters in this frame are used for room and system load calculations. For rooms with ApSys methodology they are also used for simulations when there is no attached ApacheHVAC system.

A modulating profile scheduling the operation of the cooling plant. Cooling will operate when the modulating profile value exceeds 0.5. Profiles are created and edited in APpro, the Profiles Database Manager.

In the case of ApacheSim this parameter is overridden if the space is modelled in ApacheHVAC.

The temperature set point for cooling control. This value must be greater than or equal to the Heating Set Point at all times. The Cooling Set Point can be constant or it can follow an absolute profile.

This parameter is overridden if the space is modelled in ApacheHVAC.

Parameters in this frame are defined for ApSys methodology rooms. They are used to determine a component of the auxiliary energy consumption associated with the room.

Plant profile (named ‘Plant operation’ in the space template) is a modulating profile specifying the times when auxiliary energy will be incurred. By default, settings are taken from thermal template and auxiliary energy figures defined elsewhere. Here you have the option to adjust it by selecting one of the following options from the drop-down list:

Set to heating profile : Profile is set according to heating profile

Set to cooling profile : Profile is set according to cooling profile

Set independently : a user-specified profile

If the option ‘Set independently’ is chosen, the drop-down box below becomes active with a list of modulating profiles to select from. Profiles are defined in ApPro.

(CIBSE Loads only) The fraction of solar radiation entering the space which is assumed to be scattered back out through glazing.  The value of this parameter depends primarily on internal surface solar absorptance and space geometry.

In ApacheSim, the retransmission of solar radiation is calculated directly from this data.

(not CIBSE Loads). An allowance for the thermal inertia of furniture. Lightweight furniture can be modelled by assuming that its temperature closely follows the space air temperature. Under these conditions its effect is the same as that of an increase in the thermal capacity of the air in the space. The Simulation Furniture Mass Factor is the factor by which the thermal capacity of the furniture exceeds the thermal capacity of the air. If furniture is to be ignored, a value of 0 should be entered.

The minimum percentage saturation level to be maintained in the space during periods of plant operation, as specified by the Cooling profile. If the percentage saturation in the space falls below the value entered here during plant operation, humidification will occur to meet this limit. Setting this parameter to 0% disables humidification control.

The maximum Percentage Saturation level to be maintained during periods of plant operation, as specified by the Cooling profile. If the percentage saturation in the space rises above the value entered here during plant operation, dehumidification will occur to meet this limit. Setting this parameter to 100% disables dehumidification control.

An autosized value set by ASHRAE Loads and CIBSE Loads (ApacheCalc) runs. It records the maximum level of humidification required during the run.

An autosized value set by ASHRAE Loads and CIBSE Loads (ApacheCalc) runs. It records the maximum level of space unit heating plus humidification required during the run.

An autosized value set by ASHRAE Loads and CIBSE Loads (ApacheCalc) runs. It records the maximum level of dehumidification required during the run.

An autosized value set by ASHRAE Loads and CIBSE Loads (ApacheCalc) runs. It records the maximum level of space unit cooling plus dehumidification (total cooling) required during the run.