01 clima parameters 2015 E - Università Iuav di Venezia

Climate and climatic parameters
Università IUAV di Venezia, Environmental Building Physics– Introduction to sustainability
Integrated Studio 1 – Master Degree in Architecture and Innovation
The climate in a site is defined by the long-term behaviours (20-30
years) of the atmospheric physical conditions.
Climate is pointed out by the statistical analisys of the measured
atmospheric parameters:
•
•
•
•
•
•
Climate Parameters
Solar radiation
Air temperature
Air humidity
Velocity and direction of wind
Rain precipitations
Clouds and sky covering
Fabio Peron
Climatic analisys refer to yearly mean temperature, mean temperature
of hottest and coldest month, yearly thermal excurtion, mean rain
precipitations.
Università IUAV - Venezia
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Weather stations
Radiation
z
On Earth surface arrive direct
radiation and diffuse radiation.
z
The sum of direct and diffuse
radiation
is
called
global
radiation.
z
The ratio between diffuse and
direct radiation depends on sky
covering:
z
z
A weather station makes continuous measurements of different
aspects of the weather.
Weather stations use standard instruments so that their
readings can be compared.
Università IUAV Environmental Building Physics – prof. Fabio Peron
diretta
diffusa
•values ~ 1 with overcast sky
•values 0,1-0,2 with clear sky.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Radiation
Radiation intensity: cosine law
Radiation intensity on a
surface, I [W/m2], depend
on incidence angle.
A=
An
cos ϑ
n
Bigger the incidence angle, lower
θ
the intentensity.
I = I n cos ϑ
Direct radiation
Diffuse radiation
A
Università IUAV Environmental Building Physics – prof. Fabio Peron
Radiation: daily variation
Acos θ
Università IUAV Environmental Building Physics – prof. Fabio Peron
Radiation on a surface yearly variation
800
solistizio estiv o - 21 giugno
2
radiazione su superficie orizzontale [W/m ]
700
equinozi - 23 m arzo, 21
settem bre
solistizio inv ernale - 21 dicem bre
600
500
400
300
200
100
0
0
2
4
6
8
10
12
14
16
18
20
22
24
ore del giorno
Sea level, mild latitude, North Emisphere
Università IUAV Environmental Building Physics – prof. Fabio Peron
Facing South, 45°N
Università IUAV Environmental Building Physics – prof. Fabio Peron
Radiation on a surface yearly variation
Temperature
Temperature is recorded
using thermometers housed
inside a screened envelope.
The sensor for the
temperature is a thermoresistence, for the humidity is
a capacity.
Shielded Capacitive
hygrometer and
thermometer
Various orientations, 45°N
Università IUAV Environmental Building Physics – prof. Fabio Peron
Daily temperature variation
Mechanical thermometer and
hygrometer
Daily temperature variation
The maximum intensity of solar
rays peaks around noon but the
daily high temperature is usually
observed later in the afternoon.
So why the discrepancy?
Earth's surface temperature is a
balance between incoming solar
radiation and outgoing terrestrial
radiation.
Peak temperature lags after peak
incoming solar energy because
earth continues to warm until
infrared radiation exceeds incoming
solar energy.
Temperature variation is a consequence of solar radiation variation. Maximum of
temperature presents with a log of 2-4 hour depending on the season respect to the
maximum of radiation intensity (noon). The minimum temperature presents at the end of
the night caused by the nocturnal radiation of Earth.
Sky covering can modify the Sun radiation and Earth irradiation levels and temperature
variations.
The highest temperature reading
usually occurs between 3 – 5 P.M.
local time.
Orographic effect can play a role in
max temp.
Air
Temperature
rises
Air
Temperature
falls
Daily temperature variation
Daily temperature variation
Just how warm the air heats up depend on:
• Type of soil
– Sand is a poor conductor of heat which helps to heat the
atmosphere even further
• Moisture Content
– More energy is used to evaporate the water and less is
being used to heat the atmosphere
• Vegetation cover
– Forest Canopy versus corn field versus open grass field
• Humidity
– Along with haze and cloudiness tends to lower maximum
temperature by preventing some of the sun’s rays from
reaching the ground
Yearly temperature variation
35
30
summer
T°C Media
25
T°C Max
T°C Min
20
temperatura [°C]
Daily temperature variation
15
10
5
0
winter
-5
Gen
Feb
Mar
Apr
Mag
Giu
Lug
Ago
Set
Ott
Nov
Dic
mese dell'anno
Yearly temperature variation for Venice (Marco Polo Airport 1988)
Air humidity
Daily air humidity and temperature
Water vapour enters in the atmosphere by
evaporation from water masses (lakes, oceans,
25
90
seas rivers) and vegetation
80
Exists a limit concentration of water in air. It
20
depends by temperature and is called saturation,
umidità relativa [%]
over it vapour start to condensate (saturation
pressure, ps).
Humidity content of water in the air is described
by the Relative Humidity RH, is the ratio (usually
15
60
50
percentage) between vapour pressure Pv and the
saturation
vapour
pressure
at
the
describe
how
far
the
vapour
is
from
condensation: UR 100% means saturation UR 0%
means completely dry air.
10
umidità relativa
same
40
temperature.
It
temperatura [°C]
70
RH = ϕ =
pv
ps
temperatura
30
5
0
2
4
6
8
10
12
14
16
18
20
22
24
ore del giorno
T
Precipitations
Precipitations
Florence: mean monthly data
z
z
z
z
z
Rainfall, snow, hail and fog.
Rainfall is measured in a raingauge.
Some rain-gauges record rainfall
automatically whilst others are
emptied everyday by an
observer
The amount of precipitations is
expressed in water mm
1 mm of water is equivalent to 1
liter of water on 1 m2.
Susa Valley: the passage of a
front in 2000
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Wind
z
Direction and strength of the
wind are both measured
z
A wind vane measures direction
z
An anemometer records strength
z
Wind strength can also be
measured using the Beaufort
Scale
z
Wind velocity varies quickly in
time. Mean values are needed.
Wind
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Wind rose and wind names
Wind roses
Università IUAV Environmental Building Physics – prof. Fabio Peron
Università IUAV Environmental Building Physics – prof. Fabio Peron
Wind regions - Mean velocity and direction
Wind: Beaufort Scale
Gradi
Beaufort
km/h
Denominazione
del vento
Descrizione
calma
il fumo si alza verticalmente
-
1
1-5
bava di vento
debole deriva di fumo
0,1
2
6-11
brezza leggera
le foglie stormiscono
0,3
3
12-19
brezza tesa
le foglie e i piccoli rami si
muovono continuamente
1,0
4
20-28
vento moderato
si muovono i rami, si solleva la
carta e la polvere
1,5
5
29-38
vento teso
incominciano ad oscillare i
piccoli alberi
2,5
6
39-49
vento fresco
si muovono i grossi rami, i fili
metallici sibilano
4,0
7
50-61
vento forte
si muovono i grossi alberi,
difficoltà a camminare
controvento
5,5
8
62-74
burrasca
si rompono i rami degli alberi
7,5
9
75-88
burrasca forte
i fabbricati possono subire
qualche danno
10,0
10
89-102
tempesta
gli alberi vengono sradicati,
danni considerevoli ai fabbricati
12,5
11
103-117
tempesta
violenta
danni generali
16,0
12
118-133
uragano
danni ingentissimi
-
0
Altezza delle
onde in metri
Università IUAV Environmental Building Physics – prof. Fabio Peron
z
z
z
z
Ancona
Aosta
Bari
Bologna
Bolzano
Cagliari
Firenze
Genova
Milano
Napoli
Palermo
Reggio Calabria
Roma
Salerno
Torino
Venezia
Verona
Italian wind regions
Altitudine
(m)
16
583
5
54
262
4
40
19
122
17
14
15
20
4
239
1
59
Zona di vento
2
2
2
1
1
3
2
3
1
3
3
3
2
3
1
3
1
Velocità media
(m/s)
3
2,6
3,5
1,6
0,9
4,0
1,4
3,8
1,1
2,3
3,6
3,8
2,6
1,8
0,8
2,6
0,9
Direzione
prevalente
W
N
W
SW
S
NW
NE
NE
SW
NE
SW
N
SW
SW
NE
NE
E
Standard UNI 10349
Sky covering
Pressure
z
Città o Località
CIE Skies
Pressure is the weight of the
atmosphere
When air rises pressure falls
When air sinks pressure increases
Pressure controls the type of weather
Barometers and barographs record
pressure
Clear sky
Overcast
sky
The cloud cover of a given site has appreciable impact on the quantity
and quality of light and thermal radiation from the sun and the sky. In
Italy we do not collect a lot of information about .
Ideally the cloudiness is described by the number of eighths of sky
covered. In the absence of such data it is possible to deduce the
presence of clouds from the Sunshine Relative Index ratio between
hours of clear sky and daytime.
Università IUAV Environmental Building Physics – prof. Fabio Peron
Climatic parameter:
winter external design temperature
Climatic parameter: Mounthly mean day
Is defined as the temperature with a cumulative frequency of 99% for light
buildings and 97,5% for heavy buildings.
te isn’t the absolute minimum temperature, neither the mean winter
temperature in the site. Using the first in the HVAC system design give an
extrasizing, the second an undersizing.
Climatic parameter: Degrees-day
For each month are considered the values of climatic data for each of the
24 hours of a day and are done the means for each hour.
Climatic parameter: Degrees-day
The degrees-day for a site are calculated as the sum of the differences
between the internal temperature ta (assumed 19°C) and the external
mean temperature tem in each day of the heating period. This is defined
as the period in which the external mean temperature is under 12°C.
f
DD = ∑ (t a − t em )
i
The degrees-day are proportional to the energy dispertions of a building
in a site. The DD are connected to the differences between internal and
exernal temperature and to the extention of winter season.
Degrees-day for Milano, Napoli
Degrees-day and climatic zones
The italian territory is divided in climatic
zones using the DD:
Zona A:
numero di gradi-giorno non superiore a
600;
Zona B:
numero di gradi-giorno maggiore di 600 e
non superiore a 900;
Zona C:
numero di gradi-giorno maggiore di 900 e
non superiore a 1.400;
Zona D:
numero di gradi-giorno maggiore di 1.400
e non superiore a 2.100;
Zona E:
numero di gradi-giorno maggiore di 2.100
e non superiore a 3.000;
Zona F:
numero di gradi-giorno maggiore di 3.000.
Degrees-day and climatic zones
Prov. Zona GG
Alt.
Comune
VE
E
2383
3
CAMPAGNA LUPIA
VE
E
2429
3
CAMPOLONGO MAGGIORE
VE
E
2432
4
CAMPONOGARA
VE
E
2649
1
CAORLE
VE
E
2313
4
CAVARZERE
VE
E
2313
2
CHIOGGIA
VE
E
2649
5
CONCORDIA SAGITTARIA
VE
E
2467
7
DOLO
VE
E
2348
2
ERACLEA
VE
E
2467
9
FIESSO D'ARTICO
VE
E
2348
5
FOSSALTA DI PIAVE
VE
E
2649
8
FOSSALTA DI PORTOGRUARO
VE
E
2432
7
FOSSO’
VE
E
2345
2
IESOLO
VE
E
2541
4
MARCON
2453
12
VE
E
MARTELLAGO
VE
E
2447
4
MEOLO
VE
E
2541
6
MIRA
VE
E
2541
9
MIRANO
VE
E
2348
4
MUSILE DI PIAVE
VE
E
2527
18
NOALE
VE
E
2349
3
NOVENTA DI PIAVE
VE
E
2649
5
PORTOGRUARO
VE
E
2649
11
PRAMAGGIORE
VE
E
2541
4
QUARTO D'ALTINO
VE
E
2635
10
SALZANO
VE
E
2348
3
S.DONÀ DI PIAVE
DRP 412/99
For detailed energy analysis are needed temperature, radiation, wind
velocity for each hour of a year. These are obtained by statistical analysis
of long period data.
A part of a Test Reference Year is reported in the following:
1
1
1
1
1
1
1
1
1
1
1
1
1
2
3
4
5
6
7
8
9
10
11
12
20,9
20,9
20,6
20,0
19,3
18,7
19,2
23,6
25,8
28,0
29,6
30,6
90
91
92
94
96
98
98
83
69
64
57
53
0
0
0
0
0
0
0
235
373
468
566
602
Zona A:
numero di gradi-giorno non superiore a
600;
Zona B:
numero di gradi-giorno maggiore di 600 e
non superiore a 900;
Zona C:
numero di gradi-giorno maggiore di 900 e
non superiore a 1.400;
Zona D:
numero di gradi-giorno maggiore di 1.400
e non superiore a 2.100;
Zona E:
numero di gradi-giorno maggiore di 2.100
e non superiore a 3.000;
Zona F:
numero di gradi-giorno maggiore di 3.000.
Climatic data sources
TRY (Test Reference Year)
1
1
1
1
1
1
1
1
1
1
1
1
The italian territory is divided in climatic
zones using the DD:
0
0
0
0
0
1
46
130
199
267
287
315
20
360
20
0
0
0
0
290
290
270
270
180
2,1
1,5
0,5
0
0
0
0
1,5
3,1
2,6
1,5
2,6
Università IUAV Corso di Fisica Tecnica Ambientale – prof. Fabio Peron
• Norma UNI 10349
• Dati climatici per la progettazione edile ed impiantistica - CNR PFE.
• Profilo climatico d’Italia - ENEA
• Dati “De Giorgio” - Politecnico di Milano
•
Handbook of Foundamental - ASHRAE
• NREL DOE Dati meteo per Energy+: http:/www.nrel.gov
• MeteoNorm - WMO: http://www.meteotest.ch/
• Satel-light: http://www.satel-light.com/
• National Oceanic Atmospheric Administration: http://www.noaa.gov/
• ARPA veneto: http://www.arpa.veneto.it/
• Società Italiana Meteorologia: http://www.nimbus.it
MENNELLA, C., - Il clima d'Italia nelle sue caratteristiche e varietà
e quale fattore dinamico del paesaggio, vol. I e vol. II.
Università IUAV Corso di Fisica Tecnica Ambientale – prof. Fabio Peron
Climatic data for design: standard UNI 10349
Climatic data for design - ENEA
Mean hourly data for 738 sites in Italy:
• Mean monthly temperature
• Mean monthly vapour pressure
• Daily solar radiation on horizontal and
vertical planes.
• Mean yearly
direction
wind
velocity
and
• Maximum temperature and maximum
variation during summer
Università IUAV Corso di Fisica Tecnica Ambientale – prof. Fabio Peron
Climatic data for design - CNR PFE
• Minimum, maximum and mean air
temperature
• Solar radiation
• Wind direction and velocity
• Number of raining days
• Sky cover
• Minimum, maximum and mean air
relative humidity
Università IUAV Corso di Fisica Tecnica Ambientale – prof. Fabio Peron
ASHRAE Handbook of Foundamentals
• Data and diagrams
• Rain precipitations
• Mean temperature
• Mean monthly days
• Hourly Radiation
Sintetic data around the world
Università IUAV Corso di Fisica Tecnica Ambientale – prof. Fabio Peron
Università IUAV Corso di Fisica Tecnica Ambientale – prof. Fabio Peron
Climatic data for design - METEONORM
World meteorological database from Switzerland: www.meteonorm.com
Climatic data for design - PVGIS
World meteorological data: http://iamest.jrc.it/pvgis/pv/index.htm
Università IUAV Corso di Fisica Tecnica Ambientale – prof. Fabio Peron
Climatic data for design – Energy Plus Weather
Università IUAV Corso di Fisica Tecnica Ambientale – prof. Fabio Peron
References
World meteorological data:
http://apps1.eere.energy.gov/buildings/energyplus/weatherdata_about.cfm;
Università IUAV Corso di Fisica Tecnica Ambientale – prof. Fabio Peron
Università IUAV Corso di Fisica Tecnica Ambientale – prof. Fabio Peron