I am planning on building a refrigerant superheat calculator that i can use at work. You can buy these quite readily but I thought it would be an interesting project to try.
Refrigeration engineers use superheat as one way of determining if a system is running properly. The pressure in the system is measured and then using a table the saturated temperature is found for that given pressure. Pressure temperature chart
That temperature is then subtracted from the actual temperature of the system measured with a thermometer. The resulting difference in temperature being the superheat (commonly around 6K)
I am comfortable with reading the data from sensors with my Arduino Uno and writing to an LCD screen what I am struggling with is converting from a pressure to a temperature. This is where I need help.
I found this calculator online that does exactly what I want. When i view the page source I can kind of follow what is happening i think. But don't know where to go from there.
As far as implementing the conversion in my project I could see two ways of doing this 1) manually insert the pressure/temp chart as some sort of array and parse through it, or 2) pass the sensor data straight to the formula (Which I have found below). As far as what would work/is the right way i don't know, I suspect the formula would be better but i don't know how to go about writing it as code, or in a format that I could give it a pressure variable and receive the corresponding temperature.
If anyone could offer any guidance i would be very grateful, I have tried looking around the internet for examples of this project but couldn't find anything very helpful, and thus I come here on bended knees.
Thank you
Ryan
I have found the formula below. Number 4, Vapour pressure, using the saturated pressure constants. Which is a screenshot of part of this document which has further explanations as to what the constants are and all that.