8 Factor of evaporation. H = Total heat in 1 kg of steam at working pressure above 0°C taken from steam tables in kJ/kg. T = Heat in feedwater (kJ/kg).
2256
= the latent heat of steam at atmospheric conditions.
How do you calculate latent heat of steam?
This Enthalpy for Saturated Steam can be obtained at atmospheric pressure from above Table, i.e., hg = 2676 KJ/Kg, So now Enthalpy required for saturated liquid to convert into saturated steam can be obtained as follows, Latent Heat
( he ) = hg – hf = 2676 – 419 = 2257 KJ / Kg
.
How do you measure latent heat?
- is a measure of the heat energy (Q) per mass (m) released or absorbed during a phase change.
- is defined through the formula Q = mL.
- is often just called the “latent heat” of the material.
- uses the SI unit joule per kilogram [J/kg].
What is latent heat in steam?
Latent heat of vaporization
What is the specific latent heat of vaporisation of steam?
This total is made up of two parts, sensible and latent heat. The sensible heat raises the temperature of water from 32°F to 212°F, 180.07 BTU per Lb. (Column 6). The latent heat of vaporization of water is at 212°F,
970.3 BTU per Lb.
What are the two types of latent heat?
Two common forms of latent heat are
latent heat of fusion (melting) and latent heat of vaporization
What is the unit for latent heat?
The latent heat is normally expressed as the amount of heat (in units of
joules or calories
) per mole or unit mass of the substance undergoing a change of state.
What are the three types of latent heat?
- Latent Heat of Fusion,
- Latent Heat of Vaporization,
- Latent Heat of Sublimation.
What is the heat of condensation of steam?
As the latent heat of steam at atmospheric pressure is 2257 kJ/kg the amount of flash steam produced will be 299/2257 =
0.133 kg/kg of condensate
. Flash steam can be piped to an evaporator, calorifier or vat or can be used for heating in a contact heater.
What is latent heat Short answer?
latent heat,
energy absorbed or released by a substance during a change
in its physical state (phase) that occurs without changing its temperature. … The latent heat is normally expressed as the amount of heat (in units of joules or calories) per mole or unit mass of the substance undergoing a change of state.
How do you measure latent heat of vaporization?
The specific latent heat is different for solid to liquid transition and liquid to gas transition. For example, if we want to turn 20 g of ice into water we need Q = 20 g * 334 kJ/kg = 6680 J of energy. To turn the same amount of water into vapor we need
Q =
45294 J .
Why steam has the highest latent heat?
Water has a high latent heat of
vaporization
, which is why steam burns are so dangerous. When steam burns a person’s arm for example, this energy transfer causes the steam to condense—which uses much more energy than simply changing the temperature.
Why does steam have the highest latent heat?
The energy required to completely separate the molecules, moving from liquid to gas
, is much greater that if you were just to reduce their separation, solid to liquid. Hence the reason why the latent heat of vaporization
What is the latent heat of water?
A
total of 334 J of energy
are required to melt 1 g of ice at 0°C, which is called the latent heat of melting. At 0°C, liquid water has 334 J g
− 1
more energy than ice at the same temperature. This energy is released when the liquid water subsequently freezes, and it is called the latent heat of fusion.
What is latent heat of condensation?
The latent heat of condensation is defined as
the heat released when one mole of the substance condenses
. The temperature does not change during this process, so heat released goes directly into changing the state of the substance. It is expressed as kg/mol or kJ/kg.
Is latent heat of vaporization constant?
The heat of vaporization is not a constant
. It is temperature dependent as shown in Figure 1 by the example graphs of temperature versus heat of vaporization for acetone, benzene, methanol and water.
