scholarly journals Analysis of operating conditions of a cooling installation with carbon dioxide

2019 ◽  
Vol 100 ◽  
pp. 00005
Author(s):  
Artur Bieniek ◽  
Łukasz Mika ◽  
Jan Kuchmacz
Keyword(s):  
Carbon Dioxide ◽  
Energy Efficiency ◽  
High Pressure ◽  
Thermodynamic Properties ◽  
Ambient Temperature ◽  
Air Temperature ◽  
Operating Conditions ◽  
Efficiency Ratio ◽  
Summer Period ◽  
International Regulations

In response to international regulations, natural refrigerants such as carbon dioxide are more and more frequently used in the refrigeration industry. Due to thermodynamic properties, R-744 is used in the transcritical cycle as an individual refrigerant. In the hereby article, high pressure of CO2 and air temperature values were analysed. The measurements were conducted on the gas cooler side and involved external air temperature values in the summer period between 1 June to 30 September 2018. The “Booster” installation was used in one of Polish supermarkets. Correlations required to determine the optimal pressure of carbon dioxide depending on ambient temperature were presented in the article. The equations presented hereby allowed to maximize the energy efficiency ratio. An optimal high pressure for one of the correlations from literature was calculated on the basis of the measurement of ambient temperature. Actual and optimal pressure values of carbon dioxide were compared in the analysed period of time.

scholarly journals Performance of Air Conditioning Unit under Constant Outdoor Wet-Bulb Temperature and Varied Dry-Bulb Temperature

2021 ◽  
Vol 39 (5) ◽  
pp. 1483-1490
Author(s):  
Andriyanto Setyawan ◽  
Susilawati Susilawati ◽  
Tandi Sutandi ◽  
Hafid Najmudin
Keyword(s):  
Energy Efficiency ◽  
Air Temperature ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Air Conditioner ◽  
Outdoor Air ◽  
Efficiency Ratio ◽  
Liquid Line ◽  
Discharge Temperature ◽  
Line Temperature

An experiment has been carried out for examining the performance of an air conditioning unit under constant outdoor wet-bulb temperature and varied dry-bulb temperature. During the experiment, the wet-bulb temperature of the compartment for outdoor unit was maintained at 22℃ and the dry-bulb temperature was varied from 24℃ to 36℃. The increase of outdoor air temperature results in the increase of supply air temperature, discharge temperature, suction temperature, and liquid line temperature. These cause the degradation of the air conditioner performance. An increase of power consumption by 1.4% and decrease of cooling capacity by 0.8% were observed for each 1℃ increase of outdoor air temperature. As a result, the energy efficiency ratio drops by 2% for each 1℃ increase of outdoor air temperature.

scholarly journals Methodological approach on optimizing the speed of navigation to reduce fuel consumption and increase energy efficiency of the cruising ship

Pomorstvo ◽  
2019 ◽  
Vol 33 (2) ◽  
pp. 222-231 ◽  
Author(s):  
Radoslav Radonja ◽  
Davor Pavić ◽  
Darko Glujić
Keyword(s):  
Energy Efficiency ◽  
Methodological Approach ◽  
High Energy ◽  
Operating Conditions ◽  
Travel Costs ◽  
Fuel Savings ◽  
Increase Energy Efficiency ◽  
Cruise Ships ◽  
Energy Needs ◽  
International Regulations

Modern large cruise ships have great energy needs for different technological processes on board. The energy needs depend on the operating conditions and the required speed of the ship, and the high energy requirements usually mean high fuel costs. With the enforcement of international regulations aimed at reducing environmental pollution, various measures and procedures have been proposed to increase the energy efficiency of ships. This paper outlines method that can be applied to ships without installing new or modification of existing systems and will require somewhat increased attention of chief engineer during voyage and his close cooperation with the captain. Traditionally, the required speed of the ship will be determined by the length of the fairway divided by the time that is available for travel. Analyzing originally collected data from the cruising ship it was concluded that by optimizing the speed of navigation according to the requirements of the route it is possible to achieve significant fuel savings, reduce travel costs, increase energy efficiency and reduce environmentally harmful emissions of the ship.

Critical Properties and High-Pressure Volumetric Behavior of the Carbon Dioxide + Propane System atT= 308.15 K. Krichevskii Function and Related Thermodynamic Properties

2009 ◽  
Vol 113 (20) ◽  
pp. 7243-7256 ◽  
Author(s):  
Sofía T. Blanco ◽  
Laura Gil ◽  
Pilar García-Giménez ◽  
Manuela Artal ◽  
Santos Otín ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Thermodynamic Properties ◽  
Critical Properties ◽  
Volumetric Behavior

Structural Design Considerations for Tubular Power Tower Receivers Operating at 650°C

2014 ◽  
Author(s):  
Ty W. Neises ◽  
Michael J. Wagner ◽  
Allison K. Gray
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Supercritical Carbon Dioxide ◽  
Performance Metrics ◽  
Operating Conditions ◽  
Design Parameters ◽  
Outlet Temperature ◽  
Power Cycles ◽  
The Impact ◽  
Supercritical Carbon

Research of advanced power cycles has shown supercritical carbon dioxide power cycles may have thermal efficiency benefits relative to steam cycles at temperatures around 500–700°C. To realize these benefits for CSP, it is necessary to increase the maximum outlet temperature of current tower designs. Research at NREL is investigating a concept that uses high-pressure supercritical carbon dioxide as the heat transfer fluid to achieve a 650°C receiver outlet temperature. At these operating conditions, creep becomes an important factor in the design of a tubular receiver and contemporary design assumptions for both solar and traditional boiler applications must be revisited and revised. This paper discusses lessons learned for high-pressure, high-temperature tubular receiver design. An analysis of a simplified receiver tube is discussed, and the results show the limiting stress mechanisms in the tube and the impact on the maximum allowable flux as design parameters vary. Results of this preliminary analysis indicate an underlying trade-off between tube thickness and the maximum allowable flux on the tube. Future work will expand the scope of design variables considered and attempt to optimize the design based on cost and performance metrics.

scholarly journals Spatial and Temporal Distribution of Temperature, Relative Humidity and Air Velocity in a Parallel Milking Parlour During Summer Period

2015 ◽  
Vol 15 (2) ◽  
pp. 517-526 ◽  
Author(s):  
Piotr Herbut ◽  
Sabina Angrecka ◽  
Grzegorz Nawalany ◽  
Krzysztof Adamczyk
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Ventilation System ◽  
Temporal Distribution ◽  
Operating Conditions ◽  
Air Velocity ◽  
Summer Period ◽  
Air Movement ◽  
Air Stream ◽  
Relative Air Humidity

Abstract The research aimed at determining the most significant parameters affecting the microclimate of milking parlours, such as temperature, relative humidity and air movement in a parallel milking parlour in real operating conditions. The research was conducted in the summer period, when the risk of heat stress in cattle is higher. To check welfare of cows during milking, days with air temperature >25°C and days with temperature equal or lower than 25°C were analysed. Observation and analysis were performed for air flow in milking parlour, range of supplied air stream and how air movement affects cattle. It was observed that the irregular distribution of air movement led to the development of diverse air velocity in different zones of the milking parlour (0.2-9.0 m∙s-1). As a consequence, the conditions inside the barn were not homogenous for all the cattle. A significant effect of the cows and external air temperature (which depends indirectly on orientation of the milking parlour relative to cardinal directions) on temperature increase (approx 6°C) was concluded, with relative air humidity at the level of 85-90%, during the milking, which led to systematic decrease of microclimatic comfort for cattle. Based on the conducted research, it was concluded that the design of ventilation systems in parallel milking parlours should be preceded by increased research not only on ventilation system efficiency but also on the distribution of flow ventilated air.

The Research on the Application of Two Kinds of Light Sources in the Training Venue for Physical Education of Universities

2012 ◽  
Vol 430-432 ◽  
pp. 1786-1790 ◽  
Author(s):  
Shu Fang Li
Keyword(s):  
Energy Efficiency ◽  
High Pressure ◽  
Physical Education ◽  
Lighting Design ◽  
Light Sources ◽  
Metal Halide Lamp ◽  
Sodium Lamp ◽  
Electric Light ◽  
High Pressure Sodium Lamp ◽  
Power And Energy

The energy efficiency experiment of electric light is implemented according to the lighting design of the physical training venues. In the experiment, the corresponding illumination, power and energy efficiency ratio of the commonly used high pressure sodium lamp and metal halide lamp which work under the voltage ranging from 187V to 234V are experimentally measured and the lighting effect characteristics of the two kinds of electric light sources compared, proving that the high pressure sodium light source should be employed in the training venue for physical education of universities.

scholarly journals The degradation of cellulose in ionic mixture solutions under the high pressure of carbon dioxide

RSC Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 3484-3494
Author(s):  
Sumarno ◽  
Prida Novarita Trisanti ◽  
Bramantyo Airlangga ◽  
Novi Eka Mayangsari ◽  
Agus Haryono
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Hydrothermal Process ◽  
Reducing Sugar

Cellulose processing by a hydrothermal process as well as in combination with a sonication pretreatment under a CO2 pressurization that affects the morphology and reducing sugar products.

scholarly journals Energy Assessment of Sorghum Cultivation in Southern Ukraine

Agriculture ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 695
Author(s):  
Oleg Bazaluk ◽  
Valerii Havrysh ◽  
Mykhailo Fedorchuk ◽  
Vitalii Nitsenko
Keyword(s):  
Energy Efficiency ◽  
Total Energy ◽  
Climate Changes ◽  
Field Experiments ◽  
Renewable Energy Sources ◽  
Grain Sorghum ◽  
Mineral Fertilizers ◽  
Efficiency Ratio ◽  
Energy Inputs ◽  
Southern Ukraine

Global climate changes and fossil fuel reserve depletion are drivers for the search for environmentally friendly renewable energy sources. In Europe, biomass represents the main alternative to fossil fuels. Among energy crops, sorghum is a promising crop for arid regions. The biomass yield and energy efficiency of sorghum (both silage and grain) were studied based on field experiments conducted in Southern Ukraine. The following climate changes were identified: an increase in temperature and a decrease in precipitation. The total energy inputs for sweet sorghum were estimated at 11.256 GJ/ha. The main contributors to the energy inputs are mineral fertilizers (56.99%). The experiment showed that a yield of 40.6 t/ha could be achieved with annual precipitation of 350 mm. The energy efficiency ratio was determined to be 11.18. The total energy inputs for grain sorghum was 16.081 GJ/ha. Its yield (grain) varied from 1.92 to 7.05 t/ha. The energy efficiency ratio of grain sorghum ranged from 2.8 to 16.7.

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