Can Thermodynamic Diagrams Clarify Concepts in Steam and Refrigeration Systems?

[Matutu]

hello,

I am having a lot of trouble with the last 2 questions on my end of year assignment, and i just found this forum and was wondering if anyone could help me

The questions are:

With the use of a P-v, Y-s and a P-h diagram respectively, define the important concepts and factors relating :

i saturated pressure
ii saturated temperature
iii enthalpy

For the evaporation and condensation of water in a steam processing plant and refiderant in a refrigeration plant

Questions 2

Define and describe the important properties of air and water vapour mixtures listed below as related to the building services

i Pressure
ii Temperature
iii Volume
iv Mass for ideal gasses
v applocation of general gas law
vi characteristic gas equation
vii daltons law
viii evaporation cooling
ix humidity

Any help on the above question for be greatly appeciated

I have been looking around on the web etc and in books but can not find any specific answers to these.


Thankyou very much

 

[KataKoniK]

for your post and for reaching out for help. I would be happy to assist you with your end of year assignment.

To begin, let's define some important terms that will help us understand the concepts and factors related to the use of P-v, Y-s, and P-h diagrams.

- Pressure (P) is the amount of force applied per unit area. In the context of thermodynamics, it is often measured in units of pascals (Pa) or pounds per square inch (psi).
- Volume (V) is the amount of space occupied by a substance.
- Temperature (T) is a measure of the average kinetic energy of particles in a substance. It is often measured in units of degrees Celsius (°C) or kelvin (K).
- Enthalpy (H) is the total energy of a substance, including its internal energy and the work it can do. It is often measured in units of joules (J) or calories (cal).

Now, let's address the first set of questions related to the evaporation and condensation of water in a steam processing plant and refrigerant in a refrigeration plant.

i) Saturated pressure refers to the pressure at which a substance exists as both a liquid and a vapor in equilibrium. In the case of water, this is known as the saturation pressure, and it increases with increasing temperature. A P-v diagram shows the relationship between pressure and specific volume (v) for a substance, and the point at which the liquid-vapor curve intersects with the saturation curve represents the saturated pressure.

ii) Saturated temperature refers to the temperature at which a substance exists as both a liquid and a vapor in equilibrium. In the case of water, this is known as the saturation temperature, and it increases with increasing pressure. A Y-s diagram shows the relationship between specific entropy (s) and specific volume (v) for a substance, and the point at which the liquid-vapor curve intersects with the saturation curve represents the saturated temperature.

iii) Enthalpy is an important concept in thermodynamics and is often used to describe the energy changes that occur during phase transitions, such as evaporation and condensation. A P-h diagram shows the relationship between pressure and enthalpy for a substance, and the area under the curve represents the amount of energy absorbed or released during a process.

Moving on to the second set of questions, let's discuss the important properties of air and water vapor mixtures.

i) Pressure is

 

[piercas]

Hello, it's great that you are reaching out for help with your assignment. I can provide some guidance and resources to help you understand and answer these questions.

First, let's start with the concepts and factors related to saturated pressure, saturated temperature, and enthalpy. These are all important concepts in thermodynamics and are often represented on diagrams such as a P-v (pressure-volume), Y-s (entropy-temperature), and P-h (pressure-enthalpy) diagrams.

Saturated pressure refers to the pressure at which a substance changes from a liquid to a gas at a given temperature. It is a characteristic of the substance and can be determined from the P-v diagram by looking at the point where the liquid and gas phases meet.

Saturated temperature, on the other hand, is the temperature at which a substance changes from a liquid to a gas at a given pressure. It is also a characteristic of the substance and can be determined from the Y-s diagram by looking at the point where the liquid and gas phases meet.

Enthalpy is a measure of the total energy of a system, including both its internal energy and the work required to change its volume and pressure. It is represented on the P-h diagram as the vertical distance between two points on the same isobar (line of constant pressure).

Now, let's move on to the evaporation and condensation of water in a steam processing plant and refrigerant in a refrigeration plant. These processes involve the transfer of heat and energy, and understanding the concepts of saturated pressure, temperature, and enthalpy are crucial in designing and operating these systems effectively.

For question 2, the properties of air and water vapor mixtures are important in building services as they can affect the indoor air quality and comfort of occupants. These properties include pressure, temperature, volume, mass for ideal gases, the application of the general gas law, the characteristic gas equation, Dalton's law, evaporation cooling, and humidity.

Pressure and temperature are important in determining the density of the air and its ability to hold water vapor. Volume is also important in ventilation and air conditioning systems, as it affects the flow of air and distribution of temperature. Mass for ideal gases is a measure of the amount of substance present and is important in calculating the amount of water vapor in the air.

The general gas law, also known as the ideal gas law, relates the pressure, volume, and temperature of a gas. The characteristic gas equation takes