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In this article, issues of increasing the efficiency of equipment for oil transportation are considered. The aim of this work is to optimize the control mode for the pumping unit for the transportation of oil refinery. The object of study is an electric drive pumping unit with an induction motor. Mathematical modeling is a research method. The pump unit energy consumption is calculated in various control modes. An optimal criterion for reducing energy consumption is proposed. [ABSTRACT FROM AUTHOR]

The study of existing types of profiles of screw bodies of vacuum pumps, determining the advantages and disadvantages of various types of profiles. Studying the energy efficiency problems of screw vacuum pumps, the influence of the geometry of the slots in the working cavity on the backflow and useful volume. As a result, a program was created for obtaining profile geometry. [ABSTRACT FROM AUTHOR]

In integrated electrical, heat and cold supply installations, gas reciprocating engines (GE) are widely used. The heat removed from the GE in the form of hot water with a temperature of about 90 °C is transformed into cold by an absorption lithium-bromide-chiller (ACh) with a decrease in water temperature by no more than 10...15 °C. At the same time, in order to maintain the thermal state of the GE at a safe level, the temperature of chilled water at the inlet of the engine should not be higher than 70 °C. Excessive heat is discharged into the atmosphere by the emergency discharge radiator. These losses are about 25%. A system for their utilization in refrigeration ejector chiller is proposed. With this the received addition cold can be used for supplementary cooling of the GE scavenge gas-air mixture, which is usually cooled by a radiator. But at high ambient temperatures the cooling potential of radiator can be insufficient that leads to falling the fuel efficiency of GE. It is shown that at elevated ambient temperatures additional cooling of the scavenge gas- air mixture allows to reduce specific fuel consumption and increase power output of the GE. [ABSTRACT FROM AUTHOR]

The air cooling at the inlet of gas turbine unites (GTU) in operation conditions of Kazakhstan and Ukraine was analyzed. To increase the efficiency of cooling air in actual climatic conditions a two-stage deep air cooling in waste heat recovery chillers of combined type that convert the heat of exhaust gas of GTU has been proposed as a novel approach in GTU inlet air cooling. The calculations were conducted for cooling ambient air to 15 °C by absorption lithium-bromide chiller (ACh) and down to 10 °C by absorption-ejector chiller (AECh). It was shown that air cooling in AECh provides approximately 1.5 times greater annual reduction in fuel consumption compared to cooling air in ACh. [ABSTRACT FROM AUTHOR]

The prospects of using the "night radiation effect" (NRE) for autonomous cooling systems are shown in the paper. An algorithm has been developed to search for the minimum temperature of a heating source of an absorption water-ammonia refrigeration machine (AWRM). It is shown that in AWRM there are modes with maximum energy efficiency with an appropriate combination of the composition of the working fluid and the temperatures of the heating source. The advantages of vapor compression systems (VCS) at low ambient temperatures are shown. The schemes of milk cooling systems with VCS and AWRM and using the NRE technology are proposed. [ABSTRACT FROM AUTHOR]

Evaluation of energy efficiency of a combined cooling system that uses night radiative cooling together with refrigerating machine, with accumulation of cold without a phase transition and the supply of liquid coolant (propylene glycol) to the air cooler was performed based on the results of computer simulation. In the cooling system located in Kostanay (Kazakhstan), there are radiators (12 m2) that cool the coolant at night, as well as a conventional vapor compression refrigerating machine with a reciprocating compressor. The cooling system is used to maintain air temperature at the level of 0 ± 1 °C in a small refrigeration chamber (36 m3) with a low value of heat emission from stored products and the absence of other operational heat influx. It was found that 78.8 days a year, the cooling system can maintain the required temperature due to the operation of radiators without turning on the refrigerating machine. This saves 242 kWh of electricity. Thus, the combined refrigeration system provides 7.6% reduced energy consumption, and also reduces physical deterioration of the refrigerating machine compressor for the annual cycle, which should reduce the financial costs for operating the refrigeration warehouse. [ABSTRACT FROM AUTHOR]

The energy efficiency analysis of the actual thermodynamic cycles of lithium bromide-water absorption refrigeration machines with single- and multi-stage processes of absorption and generation and with associated mass flow is carried out. The temperature influence analysis of the heating and cooling sources on the heat coefficient is performed. Parameters of external sources that allow implementation of these thermodynamic cycles are determined. Meanwhile, for cycles with two-stage absorption and generation processes, a heating source with temperature (20 ÷ 24)°C lower in comparison with the basic single-stage cycle, and for a cycle with three-stage processes – lower by (27 ÷ 30)°C is required. It has been established that with the accepted parameters of external sources, the actual coefficient of performance is within the limits: for a single-stage, lithium bromide-water absorption refrigeration machine (LBWARM) it is 0.68 ÷ 0.74, for a two-stage LBWARM, it is 0.36 ÷ 0.39 and for a three-stage LBWARM, it is 0.24 ÷ 0.26. [ABSTRACT FROM AUTHOR]