This experimental analysis shows the measured reduction in energy consumption as well as the effects of voltage on cycle temperatures, pressures, flow rates and also compressor speed （revolutions per minute）. The do...This experimental analysis shows the measured reduction in energy consumption as well as the effects of voltage on cycle temperatures, pressures, flow rates and also compressor speed （revolutions per minute）. The domestic refrigerator used R134a as refrigerant. Two energy consumption procedures were adapted from the JIS and ISO standards. The biggest difference between two standards is that the fridge is not opened in the ISO test while it is opened a number of times in the JIS test. The tests were carried out between 190 V and 250 V in steps of 10 V. The reduction in energy consumption was of 49.78 W-h per day or 6.27% of the total consumption. The experiments also showed that the voltage drop resulted in only a small rpm drop which in turn did not result in a noticeable refrigerant flow-rate change. Consequently the temperatures and pressures were not affected.展开更多
A simple theoretical model of a heat pipe heat exchanger （HPHE） based on the ε-NTU method is presented. An iterative computer program was developed to predict the overall effectiveness of a counter-flow air-air loo...A simple theoretical model of a heat pipe heat exchanger （HPHE） based on the ε-NTU method is presented. An iterative computer program was developed to predict the overall effectiveness of a counter-flow air-air loop heat pipe heat exchanger （LHPHE）. A thermal resistance network approach for a single thermosyphon was first considered to determine the overall heat transfer coefficients and the NTU＇s for the evaporator and condenser sections. The model incorporated previously determined evaporating and condensing coefficients. The overall effectiveness of the 6, 4 and 2 row LHPHE was then predicted. The theoretical overall effectiveness was compared with experimental data obtained from a R410a filled LHPHE. The experimental overall effectiveness results compared very well with the simulated values, The results showed that the 6 row arrangement performed better than the 4 or 2 row arrangement in the experiment.展开更多
文摘This experimental analysis shows the measured reduction in energy consumption as well as the effects of voltage on cycle temperatures, pressures, flow rates and also compressor speed （revolutions per minute）. The domestic refrigerator used R134a as refrigerant. Two energy consumption procedures were adapted from the JIS and ISO standards. The biggest difference between two standards is that the fridge is not opened in the ISO test while it is opened a number of times in the JIS test. The tests were carried out between 190 V and 250 V in steps of 10 V. The reduction in energy consumption was of 49.78 W-h per day or 6.27% of the total consumption. The experiments also showed that the voltage drop resulted in only a small rpm drop which in turn did not result in a noticeable refrigerant flow-rate change. Consequently the temperatures and pressures were not affected.
文摘A simple theoretical model of a heat pipe heat exchanger （HPHE） based on the ε-NTU method is presented. An iterative computer program was developed to predict the overall effectiveness of a counter-flow air-air loop heat pipe heat exchanger （LHPHE）. A thermal resistance network approach for a single thermosyphon was first considered to determine the overall heat transfer coefficients and the NTU＇s for the evaporator and condenser sections. The model incorporated previously determined evaporating and condensing coefficients. The overall effectiveness of the 6, 4 and 2 row LHPHE was then predicted. The theoretical overall effectiveness was compared with experimental data obtained from a R410a filled LHPHE. The experimental overall effectiveness results compared very well with the simulated values, The results showed that the 6 row arrangement performed better than the 4 or 2 row arrangement in the experiment.
