Università IUAV di Venezia, Environmental Building Physics– Introduction to sustainability
Integrated Studio 1 – Master Degree in Architecture and Innovation
Comfort
Comfort is the state of mind
that expresses satisfaction
with the environment
Comfort depends on:
Climate and Comfort:
Bioclimatic Chart
•
•
•
•
•
•
clothing Icl
activity, Met
Air temperature ta
Air velocity va
Air humidity Ura
Mean radiant temperature, tmr
Fabio Peron
Università IUAV - Venezia
There is not a single condition of
comfort, but comfort conditions are
defined by the endless combinations
of the six variables.
Sensations are subjective
The feeling is subjective and the same environmental conditions
on different persons can lead to different sensations.
Comfort: experimental analysis with group of testers
Comfort metrics: comfort indices
Comfort: energy budget
∑Q
Driven by the proportionality
= Q
K
+ Q
C
+ Q
R
+ Q
between the thermal load of the
human body and the feeling of
cold and warm proven by man,
Fanger in 1970 proposed a new
comfort index, the PMV
(Predicted Mean Vote)
VOTE
SENSATION
+3
+2
+1
0
-1
-2
-3
very hot
hot
slightly hot
comfort
slightly cold
cold
very cold
PMV = f (Icl, M, ta, va,URa, tmr)
Comfort indices
Qcond - conduction between body and
envelope surfaces;
Qconv - convection between body and air;
QR
- radiation between body and
envelope surfaces;;
– sensible heat associated with
Qsi
breathing;
QLi
- latent heat associated with
breathing;
ED
- sensible heat associated with
transpiration;
- latent heat associated with
ES
transpiration
.
Comfort summary
Thnaks to experimental
Fanger DTU Lyngby (DK)
analyses Fanger can connect
the comfort index, PMV, to the
environmental and Behavioural
PMV = f (Icl, M, ta, va,URa, tmr)
variables.
Starting from the energy budget
PPD = g (PMV)
equation for human body he
obtained the following:
PMV = [0.303 exp(−0.036M) + 0.028]S
PMV = [0.303 exp(−0.036 M) + 0.028][( M − L) −
− 0.305{5733 − 6.99(M − L) − pa } − 0.42{(M − L ) − 58.15} −
− 1.7 10 −5 M(5867 − pa ) − 0.0014 M(34 − ta ) −
{
}
− 3.9610 −8 fv (tv + 273)4 − (tmr + 273)4 − fv hc (tv − ta )
Sr
+ Q
Lr
+ Q
Ed
+ Q
Es
Human energy budget: metabolism
Human energy budget: metabolism
An adult sleeping or is still lying in bed,
Activity therefore produces, as basal
Reclining 46 W/m2 0.8 Met metabolism a power of 70-80 W.
Seated relaxed 58 W/m2 1.0 Met Clock and watch repairer 65 W/m2 1.1 Met values with activities: for a sitting man
Standing relaxed 70 W/m2 1.2 Met is around 100-110 W.
Car driving 80 W/m2 1.4 Met Standing, light activity (shopping) 93 W/m2 1.6 Met Walking on the level, 2 km/h 110 W/m2 1.9 Met Standing, medium activity (domestic work) 116 W/m2 2.0 Met Washing dishes standing 145 W/m2 2.5 Met Walking on the level, 5 km/h 200 W/m2 3.4 Met Building industry 275 W/m2 4.7 Met Sports ‐ running at 15 km/h 550 W/m2 9.5 Met The metabolic power M assumes higher
M is evaluated using a non S.I unit, the
met equal to 58,2 W/m2.
This
unit
value
corresponds
to
the
metabolic power per unit body surface
area developed by a man in sedentary
activity.
Human energy budget: clothing thermal resistance
0.5 Clo
1.2 Clo
Human energy budget: clothing thermal resistance
Clothing element 1.0 Clo
Underwear, shirts Shirts Trousers clothing is evaluated with a unit
Not belonging to the SI:
The clo equal to 0,155 m2K/W
Iclu Clo Iclu m2 °C/W 0,15 Clo
Underwear The thermal resistance of
Metabolic Rates [M] Insulated coveralls Sweaters Pantyhose Briefs Pants long legs Bra T‐shirt Half‐slip, nylon Tube top Short sleeves Normal, long sleeves Shorts Normal trousers Overalls Multi‐component filling Fibre‐pelt Thin sweater Normal sweater Thick sweater 0.02 0.04 0.10 0.01 0.09 0.14 0.06 0.09 0.25 0.06 0.25 0.28 1.03 1.13 0.20 0.28 0.35 0.003 0.006 0.016 0.002 0.014 0.022 0.009 0.029 0.039 0.009 0.039 0.043 0.160 0.175 0.031 0.043 0.054 Human energy budget: mean radiant temperature
Human energy budget: mean radiant temperature
Is defined as the temperature of
the envelope, black and isothermal,
Tmr = 4
of a hypothetical room which
would have the same exchange of
∑F T
ui
4
i
heat of the real room with the
person .
Ti is the temperatura of surface i
and FUi is the view factor between
man and surface i.
Note that the Tmr varies with the
location of the person in the room
Standards on comfort
•
•
•
•
Design criteria
ISO EN 7730-2005
Ergonomics of the thermal environment –
Analytical determination and
interpretation of thermal comfort using
calculation of the PMV and PPD indices
and local thermal comfort effects.
PMV-PPD and operative temperature design criteria (ISO 7730-2004).
,
Class EN 15251-2008
Indoor environmental parameters for
assessment of energy performance of
buildings, addressing indoor air quality,
thermal environment, lighting and
acoustics.
ASHRAE 55-2013
Thermal environment conditions for
human occupancy
CR 1752
– Ventilation of buildings-Design criteria for the indoor environment
•
TC156WG12 (European Energy Performance of Buildings Directive)
– Criteria for the indoor environmental quality
•
TC205WG5
Building Environmental Design - Thermal Environment
)
Comfort requirements Temperature range PPD PMV [%] [/] [°C] [°C] A < 6 ‐0.2 < PMV < + 0.2 21‐23 23.5‐25.5 B < 10 ‐0.5 < PMV < + 0.5 20‐24 23.0‐26.0 C < 15 ‐0.7 <PMV < + 0.7 19‐25 22.0‐27.0 Winter(1.0clo/1.2met) Summer(0.5clo/1.2 met) Climate and comfort: Olgyay chart
Climate and comfort: Olgyay chart
This famous
illustration is taken
from “Design with
Climate”, by Victor
Olgyay, published in
1963.
You can actually identify
two areas of comfort, a
summer and a winter one
(upper and lower), relating
to an scantily dressed (Clo =
0.8), in sedentary activity
(Met 1) and in the shade (no
solar radiation) .
This is the finite
point of expected
comfort for
100% mechanical
heating and
cooling.
The part below the comfort
zone describes conditions
undercooling, the above
overheating.
Green area is the
comfort area: we
can use different
conditions
Climate and comfort: Olgyay chart
Olgyay Chart
Point A
Air temperature:
75 °F ≅ 23,9 °C
Air Relative Humidity: 50%
A
condition:
Summer COMFORT
Winter COMFORT (limit)
No intervention:
It falls into the comfort zone
Olgyay Chart
Olgyay Chart
B
Punto B
Temperatura a bulbo secco
aria: 75 °F ≅ 23,9 °C
Punto C
Temperatura a bulbo secco
aria: 50 °F ≅ 10 °C
Umidità relativa: 70%
Umidità relativa: 56%
condizione: non COMFORT
condizione: non COMFORT
accorgimento necessario:
Moto aria: 120 fpm ≅0,61 m/s
C
Olgyay Chart
Olgyay Chart
Punto E
Temperatura a bulbo secco
aria: 95 °F ≅ 35 °C
Punto D
Temperatura a bulbo secco
aria: 87 °F ≅ 30,6 °C
D
accorgimento necessario:
radiazione: 250 Btu/(h ft2)
≅ 788 W/m2
Umidità relativa: 30%
condizione: non COMFORT
accorgimenti necessari:
vento: 300 fpm ≅ 1,52 m/s
oppure
vapore d’acqua:
8 grains/pound ≅ 1,14 g/kgas
E
Umidità relativa: 20%
condizione: non COMFORT
accorgimenti necessari:
vento: 700 fpm ≅ 1,52 m/s
in più vapore d’acqua:
8 grains/pound ≅ 1,14 g/kgas
Oppure vapore d’acqua:
22 grains/pound ≅ 3,14 g/kgas
Olgyay Chart
Olgyay Chart
Some modifications to the
original Olgyay chart:
In the chart some others
lines related to specific
conditions:
Substitution of sun
radiation (typical of
external environment)
with mean radiant
temperature Tmr (typical
of internal environment).
•
•
•
•
•
•
•
•
•
Added different clothing
resistence levels
reaching comfort
Climate and comfort: Olgyay chart
In the diagram, you can
report the climatic
conditions of the site
considered, highlighting
the " climate criticities" in
relation to the comfort .
colpo di sole
colpo di calore
congelamento delle dita
limite di congelamento
limite di sopravvivenza
limite per certe attività
limiti per vestiario
condizioni di troppo secco
condizioni di troppo
umido
Olgyay chart: considerations
The Olgyay Bioclimatic Chart is usefull for buildings design when air
temperature inside the building is next to the outside: it happens in the
summer at mid and low latitudes for humid climates , and is especially true
as more buildings are light and naturally ventilated by opening doors and
windows .
In Olgyay chart it does not consider the presence of the building
Venice climate is humid
with cold winter.
Warm periods with high
humidity (scirocco wind,
summer sultriness).
The plot is not very effective for massive buildings in hot, dry climates:
here the indoor air temperature is always very different from the outside,
without any HVAC System.
In these cases the signs of Olgyay lead to overestimation of the
interventions to ensure comfortable conditions .
Givoni chart
Givoni chart
To get around the problem that can arise from the direct use of external climatic data in
the chart, Baruc Givoni in 1969 proposed a new bioclimatic chart “Building Bio-Climatic
Chart” based on ASHRAE humid air diagram and integrating the building factor..
CE
CI
Givoni chart
Givoni vs Olgyay Charts
Differences between Givoni and Olgyay Charts:
•
Givoni consideres the presence of the building
•
In Givoni winter comfort zone is much larger than the summer(assuming heavier
clothing and more intense activity)
•
Are traced areas where the conditions of external temperature and humidity can
ensure indoor comfort using Passive Systems. They consider four main systems:
a) ventilation
b) high mass
c) radiation collection
d) evaporative cooling
the comfort zone boundaries are determined by the internal temperatures
provided by the building without plant and bioclimatically designed.
Brown Chart
Brown Chart
Brown, De Kay 2001
Brown Chart
Brown, De Kay 2001
Brown Chart
Madison (Wisconsin):
Charleston (South Carolina):
Natural ventilation can be sufficient for cooling needs
Natural ventilation can be sufficient for cooling needs
Sun radiation isn’t sufficient for the heating needs (very cold climate).
Sun radiation can be sufficient for the heating needs
Brown, De Kay 2001
Brown, De Kay 2001
Innovation and comfort: the adaptation
The context and the thermal history of each subject can change
the expectations and climatic preferences. It is the so called
adaptation which is the process of gradual decrease of the
reactions of each subject to the microclimate stimuli
behavioral adaptation (clothing, posture, activity)
It is the overall changes that a person puts into action, consciously
or unconsciously, in order to change the parameters that regulate
the heat balance of the body. It can be personal, technological and
cultural.
physiological adaptation
prolonged exposure to a certain type of environment or climate,
reduces thermal stress. This adaptation can be genetic or
acclimatization. The physiological adaptation has a negligible
influence on the perception of comfort in moderate environments.
psychological adjustment (expectations),
previous experiences and expectations change the perception of
sensory stimuli and the reaction to them.
L’approccio adattivo al comfort si basa sul principio di addattatività:
Se avviene un cambiamento che produce discomfort, le persone
reagiscono in modo da ristabilire il loro stato di comfort
Questi cambiamenti si hanno su periodi di tempo variabili e possono
essere cambiamenti effettuati sulla persona o sull’ambiente.
istantanei: mettersi o togliersi indumenti in risposta o anticipando
cambiamenti di condizioni
nel giorno: risposta a cambiamenti di ambienti durante il giorno
giorno per giorno: risposta a cambiamenti meteorologici
lungo periodo: risposta ai cambiamenti stagionali guidata dal
contesto culturale
Il comfort è visto come il risultato di un’interazione tra edificio e
occupanti in un certo contesto climatico e culturale.
Le condizioni di comfort cambiano con i cambiamenti di vestiario e con
altri fattori in funzione della stagione e del clima. Lo studio di questo
sistema di retroazione naturale ha dato dei risultati riproducibili.
Adaptation
Comfort is achieved
by the occupants
adapting to the
building
Occupant
Building
Or by the occupants
adapting the building
to suit them
All this in a specific social, economic and cultural context
Proportion of subjects comfortable
Adaptation
Innovation and comfort: the adaptation
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Little discomfort
12 14 16 18 20 22 24 26 28 30 32 34 36 38
Mean indoor temperature oC
Comfort level with various indoor temperature. Investigation in offices in Pakistan
Nicol, Raja, Allauddin & Jamy (1999) Energy and Buildings 30
Adaptation
Adaptation
Comfort temperature
35
30
25
20
15
10
15
20
25
30
35
40
Mean temperature experienced
Comfort and mean external temperature in Pakistan
Nicol, Raja, Allauddin & Jamy (1999) Energy and Buildings 30
Adaptation
50 F
59 F
68 F
77 F
86 F
95 F
86.0
24
22
NEW DELHI
BANGKOK
PALERMO
TOKYO
PERTH
TORINO
STOCKOLM
AMSTERDAM
26
FRANKFURT
28
SINGAPORE
30
o
indoor operative temperature ( C )
32
Adaptive comfort and Fanger model
82.4
78.8
75.2
71.6
90% acceptability limits
20
68.0
18
80% acceptability limits
64.4
16
60.8
14
5
10
15
20
25
30
35
o
mean monthly outdoor air temperature ( C)
ASRAE 55-2004
Adaptation
Adaptation
According to a 2009 study developed in the European offices, the comfort
temperature, Tc, varies as a function of the mobile mean of external temperature,
Trm, following the relashion:
Tc = 0,33 Trm + 18,8
Also in Europe is considered the adaptation: CEN EN15251-2007
Natural ventilation and comfort
Adaptation
•
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The standards indicate a constant temperature inside the buildings to obtain
comfort. Research in different parts of the world have put in evidence how
the temperature that is perceived comfortable varies with season and
climate
This means that comfort can be achived with less energy in a building
where the internal temperature follows the outside temperature
This means that in a well designed building we can obtain comfort conditions
also without HVAC systems
AC buildings, line B
Neutral or comfort temperature oC
•
34
Free-running buildings, line A
32
30
28
A
26
B
24
22
20
18
16
Tn = To
14
12
-24 -22 -20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0
•
It was developed an algorithm for the prediction of the comfort temperature
as a function of the outside temperature Using this algorithm to control the
set point of the air conditioning you can save 25% of energy.
2
4
6
8 10 12 14 16 18 20 22 24 26 28 30 32 34
o
Monthly mean outdoor temperature C
Humphrey in1978 from field studies. Each point represents a research campaign.
In free-running building expectations are less stringent.
Natural ventilation and comfort
Innovazione e comfort personalizzato
Brager and De Dear 2006: non ci sono errori ma un adattamento psicologico legato
all’esperienza personale e alle aspettative
Fabio Peron – Argenta, 10 settembre 2016
Innovazione e comfort personalizzato
Sistemi di ventilazione e controllo personalizzato
Sistemi di ventilazione e controllo personalizzato
Innovazione e comfort personalizzato
Sistemi di ventilazione e controllo personalizzato
Bioclimatic Chart and comfort model
Innovazione e comfort
personalizzato
scaldagambe
Poltrona riscaldata o raffreddata;
Bioclimatic Chart and design evaluations
Bioclimatic Chart and design evaluations
Climatic needs
Bibliografia
Climatic needs