Optimization of process parameters for minimum energy consumption based on cutting specific energy consumption

This article provides information about the importance of stable thermal operating modes of refrigeration machines in the condition of changes in the thermal load on the compressor. We also consider the problem of the minimum energy consumption of refrigeration machines. These two parameters characterize the storage quality of agricultural products in refrigeration machines. It is shown that the temperature stability of the cooling chambers and the minimum energy consumption of the cooling process determine the refrigerator efficiency and, ultimately, the production cost. The article proposes continuous monitoring of the heat and energy indicators of refrigerators. These indicators are recorded and after the set period of operation, control and verification measurements of the control refrigeration machine’s heat and energy indicators are performed. The convergence or divergence of these indicators is used to evaluate the stability of the cooling chambers’ temperature regimes and the specific energy consumption. We also consider the influence of time on the performance of the compression refrigeration machine changes and methods of current technical condition diagnostics. If the deviations are insignificant, the program goes through the cycle to the beginning of monitoring and after a set period of time again automatically performs control measurements and evaluation of deviations. In the case of significant deviations, the decision-making subroutine is activated: either to operate the refrigerator further; perform its maintenance; suspend its operation; or replace it. Keywords: refrigeration units, cooling, heat and power characteristics, management controller, storage quality of agricultural production

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Design and Justification of a Combined Tillage Machine

KnE Life Sciences ◽

10.18502/kls.v4i14.5582 ◽

2019 ◽

pp. 62-67

Author(s):

Andrey Ivanov

Keyword(s):

Energy Consumption ◽

Specific Energy ◽

Minimum Energy ◽

Specific Energy Consumption ◽

Kinematic Parameter ◽

Circumferential Velocity ◽

Mutual Arrangement ◽

Technological Parameters ◽

Axis Of Rotation ◽

Working Element

The tillage of soil with minimum energy consumption can be achieved by breaking the bonds between soil aggregates with tensile deformations. The design of a combined tillage machine is proposed and its technological parameters are justified. The proposed machine includes a frame with a flat working element with a leg, top and bottom rotary agitators with a drive mechanism placed behind a flat working element above each other. The design feature is that the circumferential velocity of a soil-destroying element of the lower rotary agitator is higher than the translational velocity of a machine, and the circumferential velocity of the upper rotary agitator is higher than the circumferential velocity of the lower rotary agitator. Besides, the proposed shape of a rotary agitator made along the Archimedes’ spiral does not allow soil to be collapsed by the back of a cutting edge. This reduces specific energy consumption at high quality of soil loosening. The purpose of the machine is to reduce specific energy consumption of soil treatment. This is achieved by the fact that the axis of rotation of the upper rotary agitator is shifted backwards in the direction of machine movement relative to the axis of rotation of the lower rotary agitator by h = R · sin · (arccos (– 1/λ)), where R – radius of the upper rotary agitator, λ – kinematic parameter characterizing the operation mode of the upper rotary agitator. Thus, the destruction of a pre-stressed soil formation due to tensile stresses caused by the mutual arrangement of working elements and the interconnection of machine operation modes contributes to the reduction of energy consumption.

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Process simulation of modelled reverse osmosis for desalination of seawater

Water Practice & Technology ◽

10.2166/wpt.2021.127 ◽

2021 ◽

Author(s):

Nurudeen Salahudeen

Keyword(s):

Energy Consumption ◽

Reverse Osmosis ◽

Process Parameters ◽

Specific Energy ◽

Specific Energy Consumption ◽

Solute Concentration ◽

Output Rate ◽

Water Output ◽

Rejection Factor ◽

Model Equations

Abstract Model equations for prediction of process parameters of reverse osmosis for desalination of seawater were developed via mathematical derivation from basic equations for reverse osmosis process. A model equation relating the interfacial solute concentration () with the process pressure difference () was developed. Taking the of a reverse osmosis as the basic independent variable, further model equations relating other process parameters such as the solute concentration polarity , water flux , osmotic pressure , water output rate (q), power density (Pd) and specific energy consumption (SEC) were developed. Simulation of a hypothetical reverse osmosis data using Microsoft Excel Worksheet and a Microsoft Windows 10 on a 64-bit operating system was carried out. Simulation results showed that the optimum fluid bulk concentration was = 0.0004 mole/cm3. The optimum rate of increase in the solute rejection factor per unit rise in ΔP was 0.45%. The optimum solute rejection factor was 97.6%. The optimum water output rate, specific energy consumption and power density were 103.2 L/h, 3.65 kWh/m3 and 6.09 W/m2, respectively.

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Study on Hybrid Drying with Infrared Radiation of Watermelon Seeds (Citrullus Lanatus)

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.399.173 ◽

2020 ◽

Vol 399 ◽

pp. 173-182

Author(s):

Raí M. de Oliveira ◽

Keyse S. Andrade ◽

Manoel Marcelo Prado ◽

L.G. Marques

Keyword(s):

Energy Consumption ◽

Specific Energy ◽

Minimum Energy ◽

Specific Energy Consumption ◽

Moisture Diffusivity ◽

Effective Moisture Diffusivity ◽

Air Velocity ◽

Linear Effect ◽

Source Temperature ◽

Effective Moisture

Drying characteristics of watermelon seeds using infrared (IR) heating combined to non-heated air flow were determined varying the IR source temperature and air velocity. The effects of the process variables on the effective moisture diffusivity (Deff) and specific energy consumption (SEC) were also evaluated. Experiments in the hybrid dryer were conducted with seeds arranged in a single layer and exposed to three IR temperatures levels (45, 65 and 85 W/m2) and three air velocities levels (0.4, 0.8 and 1.2 m/s) at 25°C. The effective moisture diffusivity was estimated using Fick’s diffusion model assuming negligible shrinkage and surface moisture in equilibrium with the surrounding air. Deff-values ranged from 0.62 x 10-10 to 1.83 x 10-10 m2/s, while SEC-valued varied from 29.91 to 73.16 kWh/g. Statistical analysis carried out on the experimental data indicated that the effective moisture diffusivity and specific energy consumption were significantly influenced only by the IR source temperature, which had a positive linear effect on Deff and a negative linear effect on SEC. Maximum effective diffusivity and minimum energy consumption values in hybrid drying of watermelon seeds were obtained with the use of the highest IR temperature and lowest air velocity.

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