Pengaruh Variasi Lilitan Pipa Kapiler pada Line Suction terhadap Laju Pendinginan dan Capaian Suhu Optimal Ruangan Prototype Trainer Lemari Pendingin

This study aims to find the effect of variations in the capillary tube winding on the suction line on achieving optimal temperature and room cooling rate. This study uses three variations: the capillary tube without being wrapped around the suction line, the capillary tube wrapped in half on the suction line, and the capillary tube fully wound on the suction line. Specifically, the purpose of this study was to determine the effect of variations in the capillary tube wrapped around the suction line, which led to efforts to maintain the performance of the refrigerator trainer prototype. The method used in this study uses an experimental method where the data collection process is carried out through observation and documentation. The data analysis technique used in this study uses quantitative descriptive research techniques where the research data will be tabulated and displayed in the form of tables and graphs, and data analysis is carried out to find out how much influence the achievement of the optimal room temperature and the cooling rate of the prototype trainer refrigerator room itself. From the research that has been carried out, it is obtained that the highest optimal room temperature achievement occurs in the variation of the capillary tube fully wound on the suction line, where there is an increase in the optimal room temperature achievement of 16.17% when compared to the room cooling rate using standard variations or without being wrapped. And the result in the form of the highest room cooling rate is the variation of the capillary pipe fully wound on the suction line.

Study on the Performance of Scroll Compressor Applied for Medium Temperature Refrigeration System

Recent research shows great interest in increasing energy efficiency of a refrigeration system and finding appropriate configurations to optimize its performance. One of the main component in the refrigeration system is compressor. Therefore, the compressor plays an important role in a refrigeration system for energy performance optimization. The study is aimed to experimentally investigate temperature and energy performance of a scroll compressor applied for medium temperature refrigeration systems. Tests were conducted in a water cooled medium temperature refrigeration system. Temperature performance evaluation of the compressor referred to the IEEE Standard 112, while energy efficiency of the compressor was calculated from the energy performance of the refrigeration system. The results clearly show that evaporating temperature together with degree of superheat at suction line of the compressor can significantly affect temperature performance of the scroll compressor. Results of the study have also shown significant improvement on the compressor energy efficiency accounted for 10.4% when the evaporating temperature increases from -8.3 °C to -2.4 °C.

Modelling and Simulation of a Retail Commercial Refrigeration System

Commercial food outlets in the UK are responsible for 3% of the UK total energy consumption, with refrigeration systems account for 29% of this total. This highlights the potential and importance of huge energy saving within commercial refrigeration systems. In this paper, a validated model that simulates a commercial refrigeration system installed over 2000 sqft to mimic a real express store installed at Riseholme Refrigeration Research Centre at the University of Lincoln, UK, is developed and presented. The detailed modelling of the display case using a temperature model comprising of three states include air inside the display case, products, and the evaporator. Additionally, the model presents a holistic view of the whole system with each subsystem cohesively linked together. Further focus has been given on the high temperature (HT) system due to the high level of installations of this system found in retail commercial refrigeration stores as well as low temperature (LT) systems featuring doors which decrease the heat transfer from the store into the cases. It is concluded that the trends of the simulation results for the display case temperatures, expansion valve opening degree, suction line pressures, and compressors power consumption, all have high resemblance to the trends of collected data obtained from Riseholme Refrigeration Research Centre. This supports the validation of the developed model.

Design and Fluid Dynamics Features of a Low-Flow High-Head Pump with Barske-Type Impeller

The article presents the results of research devoted to the design and numerical calculation of a low-flow high-head centrifugal pump with Barske-type impeller using computer simulation methods. The main features of fluid flow hydrodynamics, as well as the influence of a number of design geometry on the energy and cavitation characteristics of the pump, are found. The focus is on the analysis of the influence of the end gap between the impeller blades and the casing, as well as the cavitation qualities of the pump. The issue of cavitation qualities of a pump with different geometry of the pump inlet area investigated. In addition, a comparison of different outlet types and the selection of the best option provided. Analysis of the importance of installing the ribs in the suction line, taking into account the vortex structure of the flow in the impeller, was carried out. In addition, the results of changes in energy characteristics when pumping a working fluid with high kinematic viscosity are given.

Irrigation pumping stations according to the hydraulic and operational indicators of pumping units

The paper presents the conditions and the degree of reduction of water supply and pressure of pumping stations (PS) depending on the hydraulic resistance of the water-supply channels and structures of the PS and other various factors. And also, the results of studies of the hydraulic and operational modes of water-supplying machine channels and structures of irrigation pumping stations are presented. Analyzing the operating conditions of the pumping units, it was found that the reasons for the decrease in their operating parameters are the following: a) an increase in the hydraulic resistance of the suction line due to sediment deposition in the intake chamber, as well as due to siltation and clogging of the PS suction pipeline; b) an increase in hydraulic resistance due to the accumulation of air at elevated points of the pressure pipeline, in particular, on the crest of the siphon outlet of the PS; c) a decrease in the hydraulic efficiency of pumping units due to an increase in the surface roughness of the parts of the flow path, it due to the effect of solid abrasive particles entering through the suction line of the PS. Also, the work presents the results of complex laboratory and field studies to study the intensity of wear of the elements of the flow path of centrifugal and axial pumps. The alternating pulsating load leads to an increase in the force of interaction of the hydroabrasive flow with the surface of the chamber and increases its wear by 10%, and also reduces the productivity of the pumping unit to 9%.