Sea Water Thermodynamic Properties?

In summary, the user is looking for thermodynamic properties of seawater, specifically specific heat and enthalpy, in order to design a solar desalinator and determine the energy required for evaporation. They inquire about determining the enthalpy of seawater by knowing the enthalpy of salt and water. The response mentions that the density of seawater is approximately 1025 kg/m^3 and the specific heat is about 3850 J/(kg C). It also notes that there may be a unit issue with the specific heat and provides additional sources for information on the properties of seawater.
  • #1
tanky322
43
0
Im looking for thermodynamic properties of seawater, especially specific heat and enthalpy. I am designing a solar desalinator, and I am trying to determine the required amounts of energy to evaporate the water.

Is there a way in which I can determine the enthalpy of seawater by knowing the enthalpy of both salt and water?


Thank you
 
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  • #2
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  • #3
Thank you!
 
  • #4
Astronuc said:
The density of seawater is about 1025 kg/m^3 and the specific heat is about 3850 J/(kg C).

I think there is a unit issue with the specific heat of 3850 J/(Kg K), given that the specific heat of water is around 2200 KJ/(Kg K).

I just wanted to see if what I am saying here is making sense.


Thanks
 
  • #5
Kaiser Engineering did an extensive research study for the government on the thermodynamic properties of seawater about 40 years ago. The properties vary with the salinity, which also varies in different parts of the seas. It is available from the Library of Congress
 
  • #6
tanky322 said:
I think there is a unit issue with the specific heat of 3850 J/(Kg K), given that the specific heat of water is around 2200 KJ/(Kg K).
3850 is the right order of magnitude, depending on the salinity.

See here - no disclaimers required for this source:
http://www.kayelaby.npl.co.uk/general_physics/2_7/2_7_9.html
 

1. What are the thermodynamic properties of sea water?

The thermodynamic properties of sea water refer to its physical and chemical characteristics that describe how it behaves under different conditions of temperature, pressure, and salinity. These properties include density, temperature, heat capacity, conductivity, viscosity, and heat of vaporization.

2. How do salinity and temperature affect the thermodynamic properties of sea water?

Salinity and temperature have a significant impact on the thermodynamic properties of sea water. As the salinity increases, the density and heat capacity of sea water also increase, while its conductivity and heat of vaporization decrease. Temperature also affects these properties, with higher temperatures leading to lower densities and heat capacities, and higher conductivities and heat of vaporization.

3. What is the importance of understanding the thermodynamic properties of sea water?

Understanding the thermodynamic properties of sea water is crucial for various scientific studies and practical applications. These properties play a vital role in ocean circulation, climate change, marine ecology, and engineering projects such as desalination and oil extraction. They also help in predicting and mitigating the impacts of natural disasters like hurricanes and tsunamis.

4. How are the thermodynamic properties of sea water measured?

Several methods can be used to measure the thermodynamic properties of sea water, depending on the specific property being studied. Density can be measured using a hydrometer or a density meter, while temperature can be measured using a thermometer or a thermocouple. Conductivity can be measured using a conductivity meter, and heat capacity can be determined using calorimetry.

5. How do the thermodynamic properties of sea water differ from those of freshwater?

The thermodynamic properties of sea water differ from those of freshwater due to the presence of dissolved salts and other substances. These dissolved substances affect the density, heat capacity, and conductivity of sea water, making them higher than those of freshwater. Additionally, the heat of vaporization of sea water is lower than that of freshwater due to the presence of dissolved substances and the higher boiling point of sea water.

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