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Wireless Sensor Applications for Building Operation and Management
Published in Barney L. Capehart, Lynne C. Capehart, Paul J. Allen, David C. Green, Web Based Energy Information and Control Systems:, 2021
Michael R. Brambley, Michael Kintner-Meyer, Srinivas Katipamula, Patrick J. O’Neill
The minimum set of measurements required to monitor refrigerant-side performance include: 1) out-door-air dry-bulb temperature, 2) liquid-line temperature (refrigerant temperature as it leaves the condenser), 3) liquid line pressure (as it leaves the condenser), 4) suction line temperature (refrigerant temperature at the compressor inlet), and 5) suction line pressure (refrigerant pressure at the compressor inlet). In addition to the five measured quantities, several derived quantities are used in monitoring the refrigerant-side performance: 1) liquid sub-cooling, which is estimated as a difference between the condensing temperature (calculated from liquid pressure and refrigerant properties) and the measured liquid line temperature, 2) the superheat, which is the difference between the evaporating temperature (calculated from the suction pressure and refrigerant properties) and the measured suction temperature, and 3) condensing temperature over ambient, which is the difference between the condensing temperature and the outdoor-air dry-bulb temperature.
Wireless Sensor Applications for Building Operation and Management
Published in Barney L. Capehart, Timothy Middelkoop, Paul J. Allen, David C. Green, Handbook of Web Based Energy Information and Control Systems, 2020
Michael R. Brambley, Michael Kintner-Meyer, Srinivas Katipamula, Patrick J. O’Neil
The minimum set of measurements required to monitor refrigerant-side performance include: 1) outdoor-air dry-bulb temperature, 2) liquid-line temperature (refrigerant temperature as it leaves the condenser), 3) liquid line pressure (as it leaves the condenser), 4) suction line temperature (refrigerant temperature at the compressor inlet), and 5) suction line pressure (refrigerant pressure at the compressor inlet). In addition to the five measured quantities, several derived quantities are used in monitoring the refrigerant-side performance: 1) liquid sub-cooling, which is estimated as a difference between the condensing temperature (calculated from liquid pressure and refrigerant properties) and the measured liquid line temperature, 2) the superheat, which is the difference between the evaporating temperature (calculated from the suction pressure and refrigerant properties) and the measured suction temperature, and 3) condensing temperature over ambient, which is the difference between the condensing temperature and the outdoor-air dry-bulb temperature.
Refrigeration Cycles and Performance Ratings
Published in Neil Petchers, Combined Heating, Cooling & Power Handbook: Technologies & Applications, 2020
Figure 33-3 illustrates a mechanically driven refrigeration cycle on a pressure versus enthalpy (p-h) chart. The p-h chart is divided into three general areas by the saturated liquid line and the saturated vapor line. The area to the left of the saturated liquid line is called the subcooled region, the area to the right of the saturated vapor line is called the superheated region, and the area between the saturated liquid and saturated vapor lines is called the liquid vapor mixture, or wet, region. Due to the shape of this region, it is also sometimes called the vapor dome. If, for example, refrigerant at point A on the saturated liquid line absorbs heat with no change in pressure, evaporation will take place and its enthalpy will increase. Evaporation would be complete at point B on the saturated vapor line. Any additional heat absorbed at constant pressure would move the refrigerant into the superheat region, as shown by point C.
Parametric Study on Ammonia-Based Loop Heat Pipe
Published in Heat Transfer Engineering, 2022
Shail N. Shah, Sanjay V. Jain, Kamlesh Kumar Baraya, A. Madhusudan Achari
The C.C. temperature and liquid line outlet temperature were used to obtain Qsc. As a convergence criterion, the difference of QHL,Qsc and Qc.c.-amb was considered and when the value was found below 0.001, the iterations were stopped which showed that steady state condition was obtained in LHP. Temperature of C.C. (Tc.c.) was increased by 0.001 °C till the required convergence was achieved. The total capillary pressure should always be higher than the total pressure drop across the system to have passive flow of fluid. This condition was checked when the convergence criteria was achieved. The system needs restructuring if convergence is achieved but capillary pressure is lower than the total pressure drop.
Characterization of flat miniature loop heat pipe using water and methanol at different inclinations
Published in Experimental Heat Transfer, 2021
Sireesha Veeramachaneni, Srinivas Kishore Pisipaty, Dharma Rao Vedula, A. Brusly Solomon
The temperature versus history is shown for liquid line, condenser wall, evaporator wall and heater temperatures in Figures 8 and Figures 9 at heat loads of 40 W and 200 W, respectively, when methanol is used as working fluid. At 40 W heat load and 1500 s the condenser wall, liquid line, evaporator wall and heater temperatures are found to be 25.99°C, 53.64°C, 60.103°C and 93°C. However at a high heat load of 200 W and 800 s these temperatures are found to be 38.62°C, 122.15°C, 180.29°C and 292.87°C. It is also observed from Figures 8 and 9 the condenser wall temperature was found to be lower than that of liquid line temperature due to heat leakage from the evaporator wall to the liquid line by conduction. The evaporator wall temperature rose to a high value due to absence of liquid in the mesh wick, which resulted in an increase in heater temperature due to heat accumulation. Thus a dry out condition was observed at 200 W heat load in the mesh wick due to insufficient flow of liquid into the mesh wick from the compensator chamber.
Profile monitoring based on transfer learning of multiple profiles with incomplete samples
Published in IISE Transactions, 2022
Amirhossein Fallahdizcheh, Chao Wang
It is clear that the liquid line temperature profile is similar to the compressor discharge temperature profile (target profile). The evaporator inlet temperature profile has an opposite trend compared with the target profile, e.g., when the temperature in the evaporator inlet increases, the compressor temperature decreases. The evaporator outlet temperature profile is not obviously related with the target profile, but the results of correlation analysis provided in Table 12 shows they have significant correlations. As a result, we expect the three profiles with incomplete data can bring extra information to monitor the target profile.