Question: Question reference: A0001 Why there are some contradictions in studies with regards to nanofluid stability and corresponding thermal conductivity? In one of your works, the nanofluids with higher stability are not necessarily those with higher thermal conductivity. It is noticed from the literature that it is always the case that higher stability leads to a higher thermal conductivity. Some found similar patterns to your findings, some obtained more and others obtain less. May I know your opinion on this matter?
The work being referred to is titled “Evaluation and analysis of nanofluid and surfactant impact on photovoltaic-thermal systems”.
Answer: Answer reference: A0001 With regards to the work on surfactant and thermophysical property testing, I think it depends on the parameters considered and whether there is a clear causal relationship or what is being reported is an association. Stability tests are usually taken for the samples concurrently to ensure a fair comparison. The stability test is followed by testing of thermophysical properties, or depending upon the procedure that the researcher follows. Thus, it is possible for stability to vary in the period between the stability tests (zeta potential, imaging, or observing the change in thermal conductivity) and the thermophysical property tests. The type of surfactant and the suspension characteristics will differ with time. Moreover, other parameters may affect the findings, such as the impact of the suspension's pH value or the concentration of the surfactant. At this stage in nanofluid research, I believe that there is a deep need for standardization, which is something I have mentioned in my previous published work.
I recommend you to do the following:
1. Select how to measure the parameter. For instance, how are you assessing the stability? Is it the number of days? Is it zeta potential? etc. 2. Follow the evidence (measurements). Not the literature or what other mates have done. As long as the work can be replicated then it is ok. 3. Ensure to take multiple readings and average them. 4. Do the uncertainty analysis. 5. Report the procedure. 6. Consider the sources of error (you can find descriptions of it on the device's manual). This may include many aspects such as the type of probe used, the natural and forced convections, etc. 7. Report the findings, and it is completely fine to showcase the contradictions in research (with an illumination for the possible reasons). 8. If you cannot describe the process, then find a specialist (chemist/chemical eng) to help along by giving their input into the justification for the findings from a technical point of view.
Note: The question have been paraphrased and the identity of the sender have been removed to avoid copyright infringement. My answer have not been edited/modified, only correspondence and greetings have been removed to protect the identity of the sender and the context of the email exchange.
