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فيديو شرح HVAC 168 states of water in BTU on a graph. ضمن كورس التبريد والتكييف (HVAC) شرح قناة Love2HVAC with Ty Branaman، الفديو رقم 196 مجانى معتمد اونلاين
By graphing the states of water we can learn about sensible heat, latent heat in one view.
Building on what we have already learned about water and latent heat this will finally connect some missing pieces.
Similar to but different than BTU Specific heat
Specific heat: the amount of BTU to change 1 pound OF A SUBSTANCE 1F
The specific heat of water is 1 as takes 1 BTU the change 1 pound of water 1F, but specific heat can be applied fo steel food, or any other product. For example it takes 0.24 BTU to change 1 pound of air 1 F
We can add BTU to water up to 212F (0psig) in liquid state
If we think about water Boiling at 0psig its saturation temperature will be 212F. the point where it changes state from a liquid to vapor absorbing heat. this is latent heat of vaporization, sometimes referred to as latent heat of condensation. 970 BTU to change 1 pound of water from a Liquid to vapor at 212F
As we heat water vapor above 212F it becomes a superheated vapor. We can measure this as its sensible heat. The Sensible heat of steam is .5 as it takes .5 BTU to change 1 pound of water vapor 1F. If we cool steam off we DE superheat it back to its saturation point.
After water condenses back to a liquid it can be Subcooled below its saturation point. All the water in liquid state we see is subcooled liquid because its below its saturation point of 212F (0 psig) We can remove sensible heat from water all the way to 32F (0 psig).
At that point we end up at another saturation. It takes 144 BTU to melt 1 pound of water from 32F Solid to 32F Liquid. we remove 144 BTU to freeze 1 pound of water from 32 liquid to 32 vapor. This is the latent heat of fusion, it can be referred to latent heat of melting.
We can continue to Cool the solid ice below 32F. The term for this is Supercooling or Undercooling. these terms are not often used. We can supercool ice down to -460F absolute zero. Ice is less dense than water and it floats on it. Because it has a lower density it has a different specific heat than water. The specific heat of ICE is .5 BTU. It takes .5 BTU to change 1 pound of ICE 1F very similar to water vapor.
In this video we cover some textbook examples in this video we cover heating Ice from 10F to 220F vapor.
We use 1 pound of water and we also use 5 pounds of water in this example. we cover 2 different methods for calculating this.