We have to measure HEAT OUT (enthalpy) and this is the unique relevant variable, steam, water, pressure, dryness, even F1 (this HAS to be measured anyway) are not relevant.
When I speak about steam water mixing it is because I have used the method many times many years ago. But I bet that Rossi who is attracted by complications will not use this simplissim clear method. Peter On Wed, Sep 28, 2011 at 8:16 AM, Jouni Valkonen <jounivalko...@gmail.com>wrote: > First I would add to my previous message, that I think that Peter's method > is more accurate than measuring pressure. That is because in order to find > out correlation between pressure and enthalpy we need to do very careful > calibration. In short run high accuracy may be difficult to archieve, but if > experiment lasts for example 10 years continuously, then of course > calibrating pressure sensor for enthalpy calculations will give great pay > off. > > Horace wrote: > « You have again not specified the precise method you would use. > > It would appear you have a case of missing variables. The principle missing > variable is mass flow, m dot, which is best to isolate and measure directly. > » > > Actually I have defined but it is so simple that you have probably missed > it. First of course, we need to know that system is at equilibrium, i.e. > water massflow in and massflow out are both matching. If water inflow rate > varies a lot then calculations and calibrations are difficult, if system is > overflowing. That means that for sure massflow must be known and it must be > measured in calibration. > > But if system is a kettle boiler that does not overflow, then calibration > is very easy. In industrial water boilers this is the most reasonable > situation because this ensures high steam quality because we can easily > superheat steam to remove that 1-2% natural wettness of steam. This reduces > the corrosion. Superheating can also be considered in calculations so this > does not reduce the accuracy of method. > > Pressure can be measured either directly with pressure sensor (easiest and > most reliable and it is always available in pressure boilers.) or in kettle > boilers boiling water temperature can be measured or last method is to > measure steam temperature (this works only if steam is not superheated and > is thus wet. I.e. steam quality must be measured, therefore this method is > not universal). > > —Jouni > On Sep 28, 2011 7:41 AM, "Horace Heffner" <hheff...@mtaonline.net> wrote: > > > > On Sep 27, 2011, at 9:35 AM, Jouni Valkonen wrote: > > > >> 2011/9/27 Peter Gluck <peter.gl...@gmail.com>: > >>> The simplest solution is to use a Steam Water mixing valve,in > >>> which the > >>> heated mixture coming out from the demo is mixed with a constant > >>> flow of > >>> cold water, you can know the enthalpy performance in any moment. > >> > >> Indeed, continuous experiments easiest way is to use enthalpy sensors, > >> that gives as total enthalpy for any given moment. Even more simple is > >> to measure the steam pressure inside E-Cat, because it gives directly > >> the total enthalpy, but of course we need to first calibrate this kind > >> of enthalpy sensors. > >> > >> –Jouni > >> > > > > > > > > You have again not specified the precise method you would use. > > > > It would appear you have a case of missing variables. The principle > > missing variable is mass flow, m dot, which is best to isolate and > > measure directly. > > > > Best regards, > > > > Horace Heffner > > http://www.mtaonline.net/~hheffner/ > > > > > > > > > -- Dr. Peter Gluck Cluj, Romania http://egooutpeters.blogspot.com
