djdive wrote:Nice job you have made.
Thanks. This last piece of "Watt calculations" was the least time consuming of the whole adventure
djdive wrote:But i have a little question, when i read you idea over the forumula in combiantion with the EN442 and the characteristic of a heating device i a little bit curious if this is right.
Because how lower or higher the flow temperature is how unreliable the output of the forumla is.
I've checked a lot of my own calculations with the formulas used by the manufacturers; all were within 1W. Which is not surprising, considering the fact that I use the same formulas. So the only thing I can do to answer your question is to ask the manufacturers whether their formulas are OK. In other words: I can't answer your question. Though I did notice that the Radson formulas have some sort of crossover where the formula changes from the one I posted on my blog to a formula with a more linear result (no power function involved). The crossover depends on the temperatures used; but I still have to look at that in detail. So I think you do have a point here that the temperatures (or better:the differences between them) can make the formula I posted less accurate.
djdive wrote:Do you have also a calculating total power on you heating system with this formula:
Q = m.c. ΔT
or with the calculated energy as a result of the combustion heat of gas (and offcourse include efficiency of the boiler)
Some 20 years ago I worked with 2 Honeywell Magnew electromagnetic flow transmitters to measure flow, PT100 sensors inside the piping, a calibrated gas meter with calibration value correction (ijkpunt correctie) and an EVHI to calculate the right caloric value of the gas being used. That setup could produce nice figures about the efficiency of the boiler, but I don't think I'll ever have that equipment here.
I can't even measure flow right now...