Water's Crucial Role in the Efficiency of Kalina Cycle Power Generation

In summary, the Kalina Cycle is a process that uses a mixture of water and ammonia as the working fluid to produce power. The water is used to absorb ammonia at the condenser and then pressurized before being heated and released to a lower pressure level. The hot ammonia then rotates a turbine to produce electricity. The water is then cooled and mixed with the ammonia again. The role of water is to reduce the quantity of ammonia required and make the compression process more efficient. If ammonia was compressed alone, it would require much more power. The Kalina Cycle is better than an ORC cycle because it has additional equipment to separate heat and cool the system more efficiently. Overall, the Kalina Cycle is a cost-effective and efficient way to produce
  • #1
pranj5
386
5
I hope may of us here have idea about Kalina Cycle. In this process, a mixture of water and ammonia is used and ammonia is the main working fluid to rotate the turbine (or other machinery) to produce power. In this process, water is first used to absorb ammonia at the Condenser and the this water-ammonia mixture is pressurised and this pressurised mixture is heated and inside a chamber, the pressurised mixture is released to a lower pressure level and the ammonia is separated from water. This hot ammonia then rotates a turbine (or other machinery) and produce power/electricity. After that, the comparatively colder ammonia goes to the Condenser and then remixed with the water again. The water is being cooled as much as possible before being injected into the Condenser again.
Now, question is, what's the role of water here and why ammonia isn't directly being compressed. The answer is simple. If, instead of being mixed with water, ammonia will be compressed directly; the power consumption will just simply skyrocket and it would be simply impossible for the cycle to produce net power. Ammonia, like other gases, will behave in the same manner when compressed alone. But, when mixed with water, it behaves like a liquid and takes far far less energy to compress.
That's my opinion. What do other think about this matter?
 
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  • #2
Hi pranj5,
Here is what I think is happening in the Katlina cycle. Water expands by about 1600 times when boiled at 100c and atmospheric pressure. Ammonia expands by about 850 times when boiled at −33.34 °C and atmospheric pressure.
This is like an organic Rankine cycle that is including an additional distillation process. The water simply reduces the quantity of ammonia required. As the temperature rises the ammonia boils first, increasing the pressure and increasing the point that the water will boil. If the ammonia content is too low then some water vapor will enter the cycle.
It seems like a good idea, a slightly modified household unit could provide electricity, hot water and moonshine.
 
  • #3
If what you have said is true, then just the ammonia would be enough. Kindly try to calculate the power necessary to compress ammonia in gaseous state and compare that with the power needed in Kalina cycle.
 
  • #4
pranj5 said:
just the ammonia would be enough.
My opinion, is yes ammonia is enough, however water is cheaper. No calculations required.
Good Luck
 
  • #5
The ammonia here will be in closed loop and therefore whether it's more costly than water doesn't matter. What matter is the power consumption to compress ammonia alone in comparison to ammonia mixed in water. When mixed with water, ammonia will behave like a liquid and therefore much less power would be needed to compress it to higher pressure.
 
  • #6
The Kalina cycle in the link below has more equipment than an ORC cycle they both use the same OP. All the additional equipment in the Kalina cycle is to separate the heat out of the stream coming from the turbine and move the heat past the cooling liquid. The system is better because the cooling section dose less cooling. I see no compressors.

http://www.globalgeothermal.com/Thermodynamic.aspx#
 
  • #7
The pressuriser here, that pressurises the ammonia-steam mixture does the job of compression here.
 

Related to Water's Crucial Role in the Efficiency of Kalina Cycle Power Generation

What is the Kalina Cycle and how does it use water?

The Kalina Cycle is a thermodynamic process used to convert heat energy into mechanical work. Water is used in the cycle as a working fluid to transfer heat from a heat source to a heat sink. The water is heated and vaporized in the evaporator, expands and does work in the turbine, and then is condensed in the condenser. This cycle is repeated to continuously generate power.

Why is water important in the Kalina Cycle?

Water is crucial in the Kalina Cycle because it acts as the working fluid and allows for the transfer of heat energy from the heat source to the heat sink. Without water, the cycle would not be able to generate power and would not be a viable option for energy production. Additionally, water is a readily available and affordable resource, making the Kalina Cycle a cost-effective energy solution.

How does the amount of water used affect the efficiency of the Kalina Cycle?

The amount of water used in the Kalina Cycle can greatly impact its efficiency. An optimal amount of water is needed to ensure that the heat transfer process is efficient and that the water does not become too hot or too cold. If too much water is used, it can decrease the efficiency of the cycle, while too little water can cause overheating and damage to the equipment.

What are the environmental impacts of using water in the Kalina Cycle?

The environmental impacts of using water in the Kalina Cycle are minimal compared to other energy production methods. The water used in the cycle is recycled and does not produce any emissions. However, there may be some local environmental impacts, such as changes in water temperature or usage, that need to be carefully monitored and managed.

Are there any alternatives to using water in the Kalina Cycle?

While water is the most commonly used working fluid in the Kalina Cycle, there are some alternatives that can be used, such as ammonia or a mixture of ammonia and water. These alternatives may provide better performance in certain conditions, but they also have their own limitations and challenges. Overall, water remains the most practical and widely used working fluid in the Kalina Cycle.

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