Skin temperature and latent heat release Elena Saltikoff FMI (material courtesy of prof. Timo Vesala, UH) 5.10.2015Ilmatieteen laitos / PowerPoint ohjeistus1.

Slides:

Advertisements

Similar presentations

Heat and Air Temperature

Advertisements

In this presentation you will: explore the stages of the water cycle

Investigating the Temperature of Air

Chapter 5 Atmospheric Moisture. The process whereby molecules break free of liquid water is known as evaporation. The opposite process is condensation,

Chapter 10 Heat Transfer and Change of Phase

Weather Water in the Atmosphere May 14, Precipitation Precipitation is any form of water that falls from a cloud. Water vapor is the source of all.

Atmospheric Analysis Lecture 3.

Class 4a: Atmospheric moisture. Introduction to water Earth’s temperature  special properties of water.

Ch. 16: Weather (#1-2).

Atmospheric Analysis Lecture 2.

Atmospheric Moisture: Relative Humidity and Dew Point

Heat. Heat and Temperature Kinetic Molecular Theory – Is the theory that matter is made up of atoms (smallest piece of matter) and that these atoms are.

JSS17BIO1Huttula Lecture set Temperature models.

Thermodynamics, Buoyancy, and Vertical Motion

Chapter 2 Section 3 Winds.

Water in the Atmosphere Section 1 Changing Forms of Water Water in the atmosphere exists in three states, or phases. One phase is known as a gas called.

PRINCIPLES OF HEAT TRANSFER

Chapter 11 Section 2 State of Atmosphere. Temperature vs. Heat Temperature: measures the movement of molecules  Faster = Warmer  Slower = Colder  Measured.

Objectives Review Vocabulary

Moisture and Atmospheric Stability … and Instability How does is relate to cloud development and precipitation?

Chapter 23 Section 1 Handout

Atmospheric Properties II Martin Visbeck DEES, Lamont-Doherty Earth Observatory

Water in the Atmosphere Evaporation Condensation and Cloud Formation.

States of Matter and Phase Change. Phase Change Diagram.

States of Matter Phase Change Trotter Phase Change Diagram.

近地面微氣象學授課老師 : 游政谷 ( Micrometeorology near the Ground ) Micrometeorology(2)

BASIC PRINCIPLES OF HEAT & COLD. How the Body Produces Heat All food & drinks contain Calories A Calorie is the heat value of food Calories in the body.

Humidity. Remember: Water takes longer to warm and cool because of its high heat capacity. Lots of solar energy is needed to change the state of water!

Radiation and Conduction in the Atmosphere

1 Lesson 02: Humidity: Water in the Air Pages

What does the Meteorologist Really Mean???

Water in the Atmosphere. States of Matter Water vapor – gaseous form (0 to 4% by volume) Water – rain, dew, clouds, fog Ice – snow, hail, clouds.

The sun is the major force that powers wind. Wind is air moving horizontally, parallel to the surface of the earth. Movement begins as warm air meets cool.

The Water Cycle. Facts About Water Water is the most important material on earth. Water continuously changes forms so it can be used and recycled. Matter.

Clouds. Relationship of lapse rate and humidity Compare the lapse rate from the slope at 800 – 2700 & ~4700. How does this affect relative humidity?

Atmospheric Moisture. State Changes of Water Humidity Adiabatic Cooling What Makes Air Rise? Atmospheric Stability.

Lecture 8: Precipitation and Evaporation Reading: Applied Hydrology Sec on evaporation and evapotranspiration.

Photo: Pamela R. Cox 2013 Elizabethtown, Kentucky.

Water in the Atmosphere

Guided Notes on Moisture in the Atmosphere Chapter 11, Section 3.

In this presentation you will: The Water Cycle explore the stages of the water cycle Next >

Lecture 4 Precipitation (1)

Warm-up Wet floor is left to dry up. Are these examples of evaporation? Feeling cool under air-conditioner. Ironing wet clothes to dry them.

FORMS OF HEAT TRANSFER. CONDUCTION CONVECTION.

Atmospheric Moisture. Water in the Atmosphere Water vapor is the source of all condensation and precipitation Essentially all water on Earth is conserved.

Chapter 38 Weather.

Change of Phase Chapter 23. Topics  Phases  Evaporation  Condensation  Evaporation & condensation rates  Boiling  Freezing  Energy & changes of.

Chapter 15 The Atmosphere Mr. Manskopf Notes Also At

Humidity and Condensation Water is unique because it is the only substance that commonly exists in all three states of matter. Depending upon temperature,

Wicked Weather WHAT YOU LEARN How we measure humidity. How fog, frost, and dew form. Why and how clouds form. Adiabatic Cooling and Warming. How clouds.

Water Cycle, Cloud Formation, and Severe Weather.

Chapter 18 Moisture, Clouds, & Precipitation Water in the Atmosphere When it comes to understanding atmospheric processes, water vapor is the most.

States of Matter Phase Change. Water Water exists on our planet in three states. Ice, water, and water vapor What causes water to be in one phase or another?

Heat Transfer and Refrigeration Cycle

Heat Transfer and Refrigeration Cycle

Heat Transfer and Refrigeration Cycle

It’s not the heat, it’s the humidity.

Moisture, Clouds and Precipitation Standards: Concept 2: PO 14

Book 1 Section 3.2 Evaporation

COMFORT Absence of discomfort or dissatisfaction.

Heat Transfer and the Movement of Air

By Moizul Hasan Assistant Professor

States States 1 States Three states of matter : solid, liquid and gas

Water in the Atmosphere

Water in the Atmosphere

Physical and Earth Science

2.5.4c Moisture, Precipitation, and Clouds

NOTES: WATER in the AIR (11.3)

Atmospheric Moisture: Relative Humidity and Dew Point

Air Mass The air over a very large region with similar + constant properties near the surface. Ex: wind, temperature and moisture content . Cold + moist.

Presentation transcript:

Skin temperature and latent heat release Elena Saltikoff FMI (material courtesy of prof. Timo Vesala, UH) Ilmatieteen laitos / PowerPoint ohjeistus1

Good News Jochen: …if you have no lift, the hot and moist air will only make you sweat and wish for refreshment… Good news: we have the lift …taking you to 5th floor …for refreshments and optional hot and moist air (towels provided) Ilmatieteen laitos / PowerPoint ohjeistus2

Hot and moist air: Sauna Three million saunas in the world 4/5 of them are in Finland Smoke saunas and saunas heated by wood or electricity Originally the word ”sauna” has meant a pit in the ground or snow (especially dug by a bird to spend the night in it) Sauna of Sibelius in Ainola, photo from Wikipedia Ilmatieteen laitos / PowerPoint ohjeistus3

Some quantitative facts*: Temperature of air is °C ( °F) Dew point is °C, that is 40 – 60 g of water per dry air kg, relative humidity is %. Skin temperature is °C * Teeri N., The Climatic conditions of the sauna. In: Sauna studies (Teir, Collan and Valtakari, Eds.), 1976.

Skin temperatures (Ladies): (Measured by IR-radiometer, ) Before sauna: 34.4 ( ) °C After sauna: 38.3 ( ) °C After swimming in a lake 22°C (12.1°C, immediately after swimming) After cooling down 29.1 ( ) °C Inside the sauna, lower level 41.6 °C

Some qualitative facts: By throwing water on kiuas (heart made of stones) the temperature and humidity are controlled Bather feels löyly (increase in humidity, not mist) as heat on the skin (why?) Bather perspires 1 – 4 litres per hour (normal rate is 1 litre per 24 hours) Feeling of “lacking oxygen” may occur (why?)

The essence of the matter: Even a slight increase in humidity would suppress vaporization from the skin (sweating) Vaporization might reverse to condensation (same process but opposite character) Energy is transformed in the form of enthalpy from the kiuas to the skin

We have experienced latent heat Latent heat cooling, evaporationCondensation Ilmatieteen laitos / PowerPoint ohjeistus8

Conclusions: Latent heat (including ceasing vaporization) Sensible heat

Ilmatieteen laitos / PowerPoint ohjeistus10

Postscript: Oxygen content of sauna air corresponds to that at the altitude of nearly 3 km. Heat exchange due to (black body) radiation is about 1000 J/s.

Latent heat seriously Complex process of simultaneous forced convection and non-steady diffusion around a bather is treated by means of a stationary semiempirical Sherwood number for a sphere corrected by a factor for non-steady pure diffusion: h(x,t) = f(x) g(t) According to Aristotle the re-evaluation by Kulmala, Vesala, Schwarz and Smolik (Mass transfer from a drop – II. Theoretical analysis of temperature dependent mass flux correlation, Int. J. Heat Mass Transfer, 1995) can be neglected and we write for the latent heat flux: