Thermal expansion coefficient for liquids.

[Geir Onsoyen]

I am looking for a liquid with a high expansion coefficient. This liquid should act as a working fluid in a energy cycle based on a system where the working fluid does not change phase from liquid to gas.

So far I have found pentane as the most suitable liquid - but I would like to know if there are people with experience / knowledge that can help me in this case. For instance if there are mixtures of different liquids that have special properties that can be interesting.

 

[aryanscarlet]

i`ve got a doubt

HEY GUYS... I`M COMPLETELY NEW TO THIS FORUM AND AM AN AMATURE... SO BEAR WITH ME IF MY DOUBTS SOUNDS SILLY... BY THE WAY I`M IN MY FRESHMAN YEAR IN INDIA. I WANT TO MAKE A STIRLING ENGINE. PLS DO PROVIDE ME SOME GUIDING WEBSITES OR SUCH... NEXT I HAVE A DOUBT IN IT... IN A STIRLING ENGINE THE LIQUID IS HEATED BY A HEAT SOURCE... NOW MY QUESTION- I NOTICED THAT THE BOILING PT OF ACETALDEHYDE IS AROUND 20.6C.
IF I PUMP LIQUID ACETALDEHYDE AT SOME 15 OR 10C CONDITION AND THEN IF I BRING THE STIRING ENGINE TO THE ROOM TEMP THEN WILL IT WORK WITHOUT AN EXTRA HEAT SOURCE AT THE ROOM TEMPERATURE...?. OR MAYBE LIKE Geir Onsoyen SAYS MAYBE USING A LIQUID OF HIGH COEFF OF THERMAL EXPANSION, THEN WOULD IT BE WORKING BETTER? AND WILL IT BE EFFECIENT THAN THE COMBUSTION ENGINE IN TERMS OF COSTS TOO OWING TO THE RISING FUEL PRICES?

 

[astrokreng]

I would like to provide some insights on the thermal expansion coefficient for liquids and its relevance in your search for a suitable working fluid. The thermal expansion coefficient is a measure of how much a substance expands or contracts when its temperature changes. It is an important property to consider in your energy cycle system because it affects the efficiency and stability of the system.

In your case, you are looking for a liquid with a high expansion coefficient that can act as a working fluid without changing phase from liquid to gas. Pentane, with a coefficient of thermal expansion of 0.0013 K^-1, seems to be a suitable candidate. However, there may be other factors to consider in your search.

Firstly, it is important to understand the operating temperature range of your energy cycle system. Different liquids have different expansion coefficients at different temperatures. For example, water has a low coefficient at room temperature but a high coefficient at its boiling point. Therefore, it is important to select a liquid with a suitable expansion coefficient within the operating temperature range of your system.

Additionally, the chemical and physical properties of the liquid should also be considered. Some liquids may have a high expansion coefficient but may be corrosive or have low viscosity, which can affect the performance and durability of your system. It is important to find a balance between a high expansion coefficient and other desirable properties for your specific application.

Furthermore, as you have mentioned, there may be mixtures of different liquids that have unique properties that can be beneficial for your system. This is an area that requires further research and experimentation. It would be helpful to consult with experts in the field or conduct studies to determine the most suitable mixture for your specific needs.

In conclusion, while pentane may be a suitable liquid with a high expansion coefficient for your energy cycle system, it is important to consider other factors such as operating temperature range, chemical and physical properties, and the potential for mixtures of liquids. I hope this information helps in your search for a suitable working fluid.