Quote:
Originally Posted by pick1e
I understand that "heat" and "chill" were temperature measurements of the two barrels.
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That is correct, I had thermometers in the water of both barrels. Since the water was vigorously swirling, I assumed uniform temperature.
Quote:
Originally Posted by pick1e
I have only guessed that "LS temp" and "HS temp" were readings at the heat exchangers
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LS temp was measured on the 'Low Side' (cold side) refrigerant line coming from the evaporation heat exchanger. HS Temp was measured on the 'High Side' (hot side) refrigerant line coming from the condensing heat exchanger. These values were used to calculate Sub Cooling and Super Heating, respectively.
Quote:
Originally Posted by pick1e
"HS press" and "LS press" were refrigerant pressures at the heat exchangers
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Yes, I kept my manifold gauges attached when I ran the tests, and recorded the readings every five minutes.
Quote:
Originally Posted by pick1e
and "super heat" and "sub cool" were measurements of the water leaving the exchangers but before mixing with the barrel water
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No, this is not correct. I used the 'LS press' reading to refer to a PT chart for R-290 to see what the temperature should have been at that particular pressure (actually I did a curve fit on the PT chart for R-290 and derived the formula for the entire PT chart in order to save myself from interpolating every value). Then I subtracted the actual temperature from the calculated temperature to determine Sub Cooling.
Ditto Super Heating. I derived values for Sub Cooling and Super Heating, to be used in system tuning. Since the only fine adjustment I could make was refrigerant pressure. I used an excessively high Sub Cooling value to discover that I needed to lower my refrigerant pressure. I did adjust that, and the efficiency increased accordingly.
Quote:
Originally Posted by pick1e
And for COP I assume you were using a temperature approximation (Th/(Th-Tc) and not volumetric heat gain/loss, but I have no idea whether you were using the barrel temps or the heat exchanger temps or pre-barrel output temps, etc.
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Not quite. I used a power meter to determine power into the compressor for each time interval. I also knew the volume, and thus the weight of the water for each time period. Knowing this and knowing the temp change per period, I could calculate the power that was causing the change.
Then COP = power-out / power-in
I calculated this for each time interval.
-AC_Hacker