attività # 3: lettura della carta psicrometrica e costruzione di uno psicrometro |
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| indicazioni generali | ||||
| Lo psicrometro è uno strumento semplice e piuttosto diffuso per la misura
dell'umidità. Esso consiste di due termometri: uno, definito termometro a bulbo secco,
misura semplicemente la temperatura dell'aria; l'altro, definito termometro a bulbo
bagnato, ha il bulbo avvolto in una garza di cotone mantenuta umida: quindi misura la
temperatura dell'acqua a contatto con l'aria, che è inferiore a causa del calore
richiesto per l'evaporazione. Dalla contemporanea lettura dei due termometri si può
risalire, tra l'altro, all'umidità relativa e al punto di rugiada. Lo psicrometro
comunque non fornisce direttamente i valori richiesti, che si possono ricavare da una
tabella psicrometrica o da un diagramma psicrometrico. In alternativa, la conoscenza delle
formule empiriche che collegano le varie grandezze può essere utilizzata per la
predisposizione di programmi che rendono più semplici e veloci le determinazioni stesse. Materiale
di lavoro: |
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| siti internet di riferimento/approfondimento | ||||
 http://ianrwww.unl.edu/pubs/generalag/g626.htm
This Guide describes how to use a simplified psychrometric chart to better understand the relationships between air temperature and relative humidity. http://www.miamisci.org/hurricane/weatherstation.html
Making a weather station: The Miami Museum of Science http://nesen.unl.edu/activities/weather/humitidy.htm
The students will construct and use a sling psychrometer to determine relative humidity. http://www.linric.com/index.htmLinric Company is a software developer and engineering services company for the Heating, Ventilation and Air Conditioning (HVAC) industry. We produce the finest psychrometric calculation and psychrometric property software tools for HVAC engineers and others. FREE Psychrometric Chart (in Word 7.0), FREE Psychrometric Java Applet , FREE Psychrometric Program, FREE Psychrometric Excel Functions, FREE Psychrometric Function DLL... http://www.developer.com/downloads/code/javascripts/script10299.html
Psychrometric Calculations http://nwselp.epcc.edu/elp/wxcalc.html The Weather Calculator: Welcome to the El Paso National Weather Service Office's weather calculator. If you have a weather variable and need to convert it, this is the place… http://www.uswcl.ars.ag.gov/exper/relhum.htm
Relative Humidity - An Important Environmental Measurement Objective: To better understand what relative humidity measures and what it is used for. (Background - Relative Humidity Table to determine relative humidity from your recorded temperatures or calculate it yourself using the Relative Humidity Equations - Suggested Exercises) http://agronomy.ucdavis.edu/uccerice/QUALITY/psychrom.htm
Psychrometrics is the measurement of the heat and water vapor properties of air. Commonly used psychrometric variables are temperature, relative humidity, dew-point temperature, and wet-bulb temperature. http://www.bae.uky.edu/~gates/psych.htm
Psychrometric Web Page - Psychrometrics are what? http://courses.ncsu.edu/classes/wps203001/online/psychrometrics.htm
PSYCHROMETRICS by NC State University http://aeserver.ageng.ndsu.nodak.edu/envr/psyc/index.htm
Psychrometrics is the study of the physical and thermodynamic properties of air-water vapor mixtures: the relationships of these properties may be described by equations or depicted by a psychrometric chart... http://chemengineer.miningco.com/...Psychrometric Calculator http://chemengineer.miningco.com/...The properties of moist air must be known for the design of solids dryers, evaporative cooling processes, or heating, ventilating & air conditioning (HVAC) systems. Beyond these engineering applications moist air plays a significant role in everyday live. Formation of fog and other meteorological phenomena as well as the wetting of walls and panes are governed by the properties of moist air. |
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