EVALUASI DAN OPTIMASI EFISIENSI ENERGI SISTEM CHILLER DENGAN PROSES DESCALING

Chiller system consumes most energy (around 50%) of the electrical energy in a building. To reduce the use of energy, it is necessary to evaluate the use of energy and identify opportunities for energy savings and recommendations for increasing efficiency. The evaluation aims to ensure that a chiller system works and produces chilled water products as designed. The chiller system evaluation includes the evaluation of the chiller refrigeration system, power consumption, cooling capacity, as well as the evaluation of the piping system and pumps. Evaluation is carried out on the system before and after repairing/descaling on the chiller system. The results of the evaluation and optimization of the chiller system are: the chilled water temperature output drops to 15oC, the cooling capacity of the chiller rises to 30 KW, the pressure of the condenser coolant pump rises to 0.58 bar. While the efficiency of the circulating pump system is 15.8%; efficiency of condenser cooling pump is 19.3% and distribution pump system efficiency is 14.1%.   Keywords: performance evaluation, optimization, chiller system

PENGARUH LAJU ALIRAN UDARA TERHADAP KINERJA SISTEM REFRIGERASI PADA TATA UDARA SENTRAL

The work of refrigeration system incentral air conditioning should be set to the cooling load to obtain the peak performance of the system with efficient energy consumption. One factor that affect to the the cooling load is the conditioned air flow rate suppliedin the system.The experiment is conducted by varying air flow rate (with 4 variations which is 1,152; 1,184; 1,216 and 1,280 m3/s respectively), to aim the optimum performance of the refrigeration system in the air conditioning system (central AHU) to consumption efficient levelof power. The results is that the refrigeration system performance is not much influenced by variations ofair flow rate,where the highest coefficient of performance (COP) of the refrigeration system (5.69) was obtained by air flow rate (debit) of 1,184 m3/s, about 4% of the COP on the largest debit. The highest compression ratio (3.5) was obtained at lowest air  flow rate (1.152 m3/s), and the lowest average of power consumption is obtained at the lowest air flow rate 1.152 m3/s, 9% lower than power consumption at thegreatest air flow.While the performance of the HVAC system is affected by variations in air flow rate, where is the greatest cooling capacity (62.364 kW) and the highest EER (3.99) was obtained at the highest flow rate of 1.280 m3/s.   Keywords: air flow rate, performance, central air conditioning

Pengukuran Tingkat Motilitas Sperma Berdasarkan Linearitas Sperma Menggunakan Metode Adaptive Local Threshold Dan Ellipse Detection

Technology that can be used toassist sperm examination is Computer-Aided Sperm Analysis (CASA). The problems with this technology are expensive and the methods are not open for public. A lot of researches have been done to have an altenative CASA's method to examine sperm quality accurately, inexpensively, and fast. This research is focused on measuring the level of sperm motility. Visual observations of sperm motility greatly depend on each andrologists which are subjective and also the possibility of repetition for the examined sample does not exist. Moreover, visual observation cannot provide precise values for parameters that affect the sperm motion patterns which are Velocity Straight Line, Velocity Curvilinear Line, and Linearity. Focus of this research is to create an application using sperm detection method, Local Adaptive Threshold and Ellipse Detection to measure sperm linearity to determine the level of sperm motility based on the WHO standard. Experiment produces result with the smallest difference 5.7333% and the biggest difference 10.4667% compared to the result of visual analysis by andrologist

PENGUKURAN TINGKAT MOTILITAS SPERMA BERDASARKAN LINEARITAS SPERMA MENGGUNAKAN METODE ADAPTIVE LOCAL THRESHOLD DAN ELLIPSE DETECTION

Technology that can be used toassist sperm examination is Computer-Aided Sperm Analysis (CASA). The problems with this technology are expensive and the methods are not open for public. A lot of researches have been done to have an altenative CASA’s method to examine sperm quality accurately, inexpensively, and fast. This research is focused on measuring the level of sperm motility. Visual observations of sperm motility greatly depend on each andrologists which are subjective and also the possibility of repetition for the examined sample does not exist. Moreover, visual observation cannot provide precise values for parameters that affect the sperm motion patterns which are Velocity Straight Line, Velocity Curvilinear Line, and Linearity. Focus of this research is to create an application using sperm detection method, Local Adaptive Threshold and Ellipse Detection to measure sperm linearity to determine the level of sperm motility based on the WHO standard. Experiment produces result with the smallest difference 5.7333% and the biggest difference 10.4667% compared to the result of visual analysis by andrologist

STUDI EKSPERIMENTAL, PENGARUH APLIKASI LIQUID TO SUCTION HEAT EXCHANGER TERHADAP KINERJA SISTEM REFRIGERASI DENGAN REFRIGERAN R 404 A

Study of performance improvement of refrigeration systems with the R404a refrigerant have been experimentally studied using a liquid to suction heat exchanger (LSHX). The use of three LSH X�s wich having each area of heat transfer 62.80 cm 2 , 75.97 cm 2 and 151.94 cm 2 is to test the system with and without LSHX at the cabin temperature setting 0°C,-10 °C and -20°C. The results of tests showed that each LSHX has heat exchange effectiveness in average of 0.35, 0.45 and 0.58. The effect of LSHX usage at refrigeration system is to increase the Coefficient of Performance (COP) with the highest increase in LSHX-1 st application which has the highest. Tests also showed that the LSHX application at low temperature settings (-10 °C and -20 o C) increase the cooling capacity, with the highest increasing in LSHX-2 nd with the medium effectiveness. While the achievement of temperature setting (chilling time) testing with LSHX is longer compared to test without LSHX, with the longest average time achievement on the test with LSHX-2