That is a dramatic drop off isnt it. As you say, the flow temperature drops (or rises less), and of course this shows up as lower output. As you say, instead of the evaporating happening outside, some of it is happeneing inside the compressor. If it all evaporated there, the COP would be 1! That is a long time for this to be happening… 10 mins. I guess the discharge temperature will be very low, and normally this would ‘signal’ for the expansion valve to close. Are we seeing the water flow-rate reducing when it sees the dt recucing?? There is of course a lag before a flooded evaporator corrects itself, and many compressors would be signalled to rev-up if discarge temp is dangerously low, in order to get out of trouble.
I need to spend a bit of time looking at the graphs… excuse my forgetfulness, but I struggle to remember whos system is who’s.
I could believe that as they ‘tune’ systems to be more energy-efficient, and like a performance car, it may cough and splutter occasionally. Are we seeing a cough? If they change the algorythm to fix this, they might reduce the net averge COP, but I really have no idea. I do have a hunch that the normal sampling rate for feed-back control is too slow. maybe it has been fine for air con. Maybe they all need to sample more often… Its only a hunch though. Maybe for the maunfacturers point of view, its not a big enough or frequent enough problem?
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