Appendix¶
PPD¶
For more information on PPD (percentage of people dissatisfied), see ISO 7730-1984 (E): Moderate thermal environments – Determination of the PMV and PPD indices and specification of the conditions for thermal comfort.
External Work¶
Due to the inefficiency of our bodies the total amount of energy we produce (metabolic rate) does not equal the amount of work we get out (External work). The rest of the energy is transferred into bodily heat production and that is the value we are interested in when assessing comfort and calculating PPD.
External Work is measured in \(W/m^2\) and must be less than metabolic value when measured in \(W/m^2\) .NB: In Ambiens, metabolic value is measured in metabolic units (met) and 1 met = 58 \(W/m^2\)
External Work is zero for most activities. For more information on External Work see ISO 8996-1990: Ergonomics: Determination of Metabolic heat production.
Metabolic value¶
These are the metabolic rates of different activities.
Activity |
Metabolic Rate (in Met) |
|---|---|
Reclining |
0.8 |
Seated, relaxed |
1.0 |
Standing, relaxed |
1.2 |
Sedentary activity (office, dwelling, school, laboratory) |
1.2 |
Standing activity (shopping, laboratory, light industry) |
1.6 |
Standing activity (shop assistant, domestic work, machine work) |
2.0 |
Medium activity (heavy machine work, garage work) |
2.8 |
The metabolic rate (met) is measured in metabolic units.
The values contained in the tables were taken from ISO 7730-1984 (E): Moderate thermal environments – Determination of the PMV and PPD indices and specification of the conditions for thermal comfort.
For more information on Metabolic Values see ISO 8996-1990: Ergonomics: Determination of Metabolic heat production.
Clothing Value¶
These are estimations of the clothing values of typical ensembles
Clothing Ensemble |
Clothing Value (in clo) |
|---|---|
Nude |
0 |
Shorts |
0.1 |
Typical tropical clothing ensemble: (Briefs, shorts, open-neck short with short sleeves, light sock and sandals) |
0.3 |
Light summer clothing: (briefs, long light-weight trousers, open-neck shirt with short sleeves, light socks and shoes) |
0.5 |
Light working ensemble: (light underwear, cotton work shirt with long sleeves, work trousers, woolen socks and shoes) |
0.7 |
Typical indoor winter clothing ensemble: (underwear, shirt with long sleeves, trousers, jacket or sweater with long sleeves, heavy socks and shoes) |
1.0 |
Heavy traditional European business suit: (cotton underwear with long legs and sleeves, shirt, suit including trousers, jacket and waistcoat, woolen socks and heavy shoes) |
1.5 |
The clothing value is measured in units of thermal resistance of clothing (clo).
These are estimations of the thermal resistance of individual garments. To obtain the clothing value; sum all the clothing values of individual garments needed for a typical clothing ensemble.
Garment |
Clothing Value (in clo) |
|---|---|
Pantyhose |
0.01 |
Light socks |
0.03 |
Heavy socks |
0.04 |
Bras and panties |
0.05 |
Half slip |
0.13 |
Full slip |
0.19 |
Briefs |
0.05 |
Undershirt |
0.06 |
T-shirt |
0.09 |
Light short sleeved shirt |
0.20 |
Light long sleeved shirt |
0.28 |
Heavy short sleeved shirt |
0.25 |
Warm skirt |
0.22 |
Light dress |
0.17 |
Heavy dress |
0.63 |
Light short sleeved sweater |
0.17 |
Heavy long sleeved sweater |
0.37 |
Heavy jacket |
0.49 |
Light trousers |
0.26 |
Medium trousers |
0.32 |
Heavy trousers |
0.44 |
Light shoes |
0.04 |
The values contained in the tables were taken from ISO 7730-1984 (E): Moderate thermal environments – Determination of the PMV and PPD indices and specification of the conditions for thermal comfort
Sample Projects¶
Example models created in Ambiens can be found in the “sample projects” data directory, they are:
AtriumWin: this is an example of warm air trench heating.
Case1: Backward facing step validation sample V=1 m/s.
Case2: Backward facing step validation sample V=5 m/s.
Case3: Backward facing step validation sample V=1.25 m/s.
Cavity: Validation sample of laterally heated cavity.
Chilled Beam: this is a model of a chilled beam being used to cool a room on a cold day. To model the cooling effect of the beam, a gain with a negative value for sensible gain is being used. This room also contains a displacement ventilation system which is bringing in air at a constant volume and temperature.
Chilled Ceiling: this is a model of a chilled ceiling cooling a room on a hot day. Note that to model this, the chilled ceiling’s target temperature is lower than the initial temperature. The room also contains a displacement ventilation system which is bringing in air at a constant volume and temperature.
Class: Classroom cross-ventilation
DispChill: example of displacement ventilation and chilled beams. This file does not use a thermostat to control the chilled beams.
Example: typical atrium cross-section
Fancoil: This is a room with a fancoil unit which is heating the room on a cold day. The thermostat is being used to control the temperature of air coming through the inlet. There is an inlet which is be used to model infiltration.
LaminarPlate: validation sample for laminar flow heat transfer
Room: single sided ventilation
Smallcavity: smaller scale cavity showing grid independence
TurbulentPlate: validation sample for turbulent flow heat transfer
Tutorial: this is the model used to help with guide.
Winrad: example of a radiator placed under a window