Hallo! I made simple steam sparging experiment by measuring the steam quality and enthalpy of my Espresso machine's steam wand (for making capuchino).
– 200ml cool water (11°C) was measured into tea cup. – Steam was sparged into mug for 32 seconds and there was not observed splattering or escaping steam – After sparging temperature was measured at 38°C, thus ΔT was 27K – the total enthalpy was calculated 4160J×27×0.20 = 22.5 kJ and power 0.70 kW. – Water level rose approximate 15ml ± 5ml. As my instruments were too crude, I could not calculate steam quality in any reasonable accuracy. If it is assumed 100% quality steam, then total enthalpy should be 22.7–45.4 kJ therefore steam quality was something between 99.1% and 49.6%. Therefore I failed with steam quality measurements. However for calculating enthalpy, steam quality is irrelevant. And also I did not observe any reasons why there should not be two or even three significant digits, if measurements were done carefully. Horace has said that there are numerous potential errors, but I did not observe any of his objections: Horace wrote: «I would note that steam sparging can have large errors due to steam escaping, due to variability in measuring the temperature decline curve, due to variations in the calorimetry constant with temperature, and due to imperfect stirring techniques.» There was not significant steam escaping. Temperature decline was irrelevant, because experiment lasted only 32 seconds. And stirring is irrelevant, because sub-boiling water needs to be stirred only before final temperature is measured. Steam sparging is very accurate, fast and simple to do method for calorimetry, therefore Horace's objections are out of proportions. –Jouni PS. I also calibrated my thermometer and I noticed that it was very poor. 0°C water was -6°C. I have also some doubts if the scale is accurate, because 11°C was somewhat reasonable temperature for cold tap water. However 38°C was too small value, because water was somewhat hotter than hand, although it was not burning hot. Anyways, I guess that this thermometer is good for measuring temperature at Incineration plant.
