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Index

Room Variables

 
These variables are accessed by selecting a room or a set of rooms in the browser or the building graphic.
Note that a room may be served by either an Apache System or an ApacheHVAC system, if one is present.
 
Air temperature: The mean temperature of the air in the room.
 
Dry resultant temperature: The mean of the room air and mean radiant temperatures.
 
Environmental temperature: A 2:1 weighted average of mean radiant temperature and air temperature
 
Mean radiant temperature: The uniform temperature of an imaginary enclosure in which radiant heat exchange with the human body would equal the radiant heat exchange occurring in the room.
 
Dew-point temperature: The dew-point temperature of the air (the temperature at which the air would become saturated if cooled).
 
People dissatisfied: An index that predicts the percentage of occupants expressing dissatisfaction with the room thermal environment. The index is calculated on fixed values for CLO 0.5, Activity 58.2 w/m2, Air speed 0 m/s, and simulated room air temperature & room mean radiant temperature variable values. Use the VistaPro Comfort analysis tool to display a version of this index that utilizes room comfort parameters & specific standard requirements, variables generated from the analysis will be tagged with chosen standard.
 
Predicted mean vote: An index* that predicts the mean value of the votes of a large group of occupants on the following 7-point thermal sensation scale:  +3 hot +2 warm +1 slightly warm 0 neutral -1 slightly cold -2 cool -3 cold. The index is calculated on fixed values for CLO 0.5, Activity 58.2 w/m2, Air speed 0 m/s, and simulated room air temperature & room mean radiant temperature variable values. Use the VistaPro Comfort analysis tool to display a version of this index that utilizes room comfort parameters & specific standard requirements, variables generated from the analysis will be tagged with chosen standard.
 
Operative temperature: temperature based on CIBSE A equation 1.2 (Air temperature & mean radiant temperature) and room air speed as set on the room comfort parameters.
 
Standard effective temperature (SET): the temperature of an imaginary environment at 50% relative humidity, <0.1 m/s [0.33 ft/s] average air speed, and mean radiant temperature equal to average air temperature, in which total heat loss from the skin of an imaginary occupant with an activity level of 1.0 met and a clothing level of 0.6 clo is the same as that from a person in the actual environment, with actual clothing and activity level and room air speed (fixed winter 0.1 m/s, summer 0.8 m/s).
 
 
Comfort index: An index predicting comfort within the space based on the following scale:
1: very cold, danger
2: cold, shivering
3: cool, unpleasant
4: cool, acceptable
5: slightly cool/acceptable
6: comfortable, pleasant/cool
7: comfortable, pleasant
8: comfortable, pleasant/warm
9: slightly warm/acceptable
10: warm, acceptable
11: warm, unpleasant
12: hot, very uncomfortable
13: very hot, danger
14: unoccupied
15: non-sedentary
 
Relative humidity: The water vapour pressure of the air expressed as a percentage of the saturation vapour pressure.
Moisture content: The water vapour content of the air (mass of water vapour expressed as a fraction of mass of dry air).
Room CO2 concentration: the volumetric concentration of carbon dioxide in the room (parts per million).
Space conditioning sensible: Sensible heat (or if negative, cooling) supplied to the room by its Apache System or ApacheHVAC system. This consists in general of two terms: a contribution from the room conditioning plant (or HVAC radiators, direct acting heaters and chilled beams) and a contribution from the system air supply.
Steady state heating plant load: Heating plant sensible load calculated under steady state conditions by CIBSE Loads (heating plant sensible load is calculated from this by application of an intermittency factor).
Heating plant sensible load: Sensible heating (non-negative) supplied to the room by its Apache System room conditioning plant or ApacheHVAC room units (radiators, direct acting heaters and chilled beams)
Cooling plant sensible load: Sensible cooling (non-negative) supplied to the room by its Apache System room conditioning plant or ApacheHVAC room units (radiators, direct acting heaters and chilled beams).
Internal gain: Sensible heat (or if negative, cooling) supplied to the room by equipment, lights, people and other heat sources specified as Internal Gains.
Solar gain: Solar radiation absorbed on the internal surfaces of the room, plus solar radiation absorbed in glazing and transferred to the room by conduction.
External conduction gain: Heat conducted into (or if negative, out of) the room through the internal surfaces of externally exposed elements, including ground floors.
Internal conduction gain: Heat conducted into (or if negative, out of) the room through the internal surfaces of wall partitions, internal floors/ceilings and elements with adjacent condition 'Temp from profile' or 'Outside air with offset temp.'.
Conduction gain: Combined external and internal conduction gain (CIBSE Loads only)
Air system input sensible: The sensible heat gain (or if negative loss) from the air system. In the case of an Apache System of type Generic, this is the sensible gain from the (possibly conditioned) outdoor air supply.
Aux vent gain: The sensible heat gain (or if negative loss) from Auxiliary Ventilation air exchanges.
Natural vent gain: The sensible heat gain (or if negative loss) from Natural Ventilation air exchanges.
Infiltration gain: The sensible heat gain (or if negative loss) from Infiltration air exchanges.
MacroFlo ext vent gain: The sensible heat gain (or if negative loss) from MacroFlo-calculated air flows entering the room from the external environment.
MacroFlo int vent gain: The sensible heat gain (or if negative loss) from MacroFlo-calculated air flows entering the room from adjacent rooms.
System air supply: The air supply associated with the system. In the case of an Apache System of type Generic, this is the outdoor air supply.
Aux mech vent: The flow of air into the room from Auxiliary Mechanical Ventilation air exchanges.
Natural vent: The flow of air into the room from Natural Ventilation air exchanges.
Infiltration: The flow of air into the room from Infiltration air exchanges.
MacroFlo ext vent: The sum of MacroFlo-calculated air flows entering the room from the external environment.
MacroFlo int vent: The sum of MacroFlo-calculated air flows entering the room from adjacent rooms.
Space conditioning latent: The latent heat equivalent of water vapour added to (or if negative, removed from) the room by its Apache System or ApacheHVAC system. This consists in general of two terms: a contribution from the room conditioning plant (or HVAC radiators, direct acting heaters and chilled beams) and a contribution from the system air supply.
Humidification plant load: The (non-negative) latent heat equivalent of water vapour added to the room by its Apache System room conditioning plant (if present).
Dehumidification plant load: The (non-negative) latent heat equivalent of water vapour removed from the room by its Apache System room conditioning plant (if present).
Cooling + dehum plant load: the sum of cooling and dehumidification plant loads.
Internal latent gain: The latent heat equivalent of water vapour added to (or if negative, removed from) the room by equipment, people and other heat sources specified as Internal Gains.
Equipment latent gain: The internal sensible gain from equipment.
People latent gain: The internal sensible gain from people.
Number of people: The number of people in the room.
DHW heating demand: The DHW heating demand at the room’s hot water outlets  (i.e. excluding pipe and tank losses) calculated on the basis of a 50K temperature rise from the cold water main.
Air system input latent: The latent heat equivalent of water vapour added to (or if negative removed from) from the space by the air system. In the case of an Apache System of type Generic, this is the latent gain from the (possibly conditioned) outdoor air supply.
Vent/infiltr. latent gain: The combined latent heat gain (or if negative loss) from Auxiliary Mechanical Ventilation, Natural Ventilation and Infiltration air exchanges.
Aux vent lat gain: The latent heat gain (or if negative loss) from Auxiliary Ventilation air exchanges.
Natural vent lat gain: The latent heat gain (or if negative loss) from Natural Ventilation air exchanges.
Infiltration vent lat gain: The latent heat gain (or if negative loss) from Infiltration air exchanges.
MacroFlo ext vent lat gain: The latent heat gain (or if negative loss) from MacroFlo-calculated air flows entering the room from the external environment.
MacroFlo int vent lat gain: The latent heat gain (or if negative loss) from MacroFlo-calculated air flows entering the room from adjacent rooms.
Convective room plant load: The convective component of the sensible heat input from Apache System room conditioning plant or ApacheHVAC room units (provided as an input to MicroFlo).
Convective lighting gain: The convective component of the sensible heat input from lights (provided as an input to MicroFlo).
Convective equipment gain: The convective component of the sensible heat input from equipment (provided as an input to MicroFlo).
Convective people gain: The convective component of the sensible heat input from people (provided as an input to MicroFlo).