Energy balance of the carbon dioxide injection facility in Ketzin, Germany

Energy that plays an important role in everyday life is electricity. The need for electricity is really important, because most daily devices uses electrical energy. However, the rapid development of technology has increased the use of electrical energy. The current demand for electrical energy is close to the production capacity of electrical energy. Excessive use of electrical energy is one of the triggers for the large increase in electrical energy consumption apart from the increase in new loads by development. The effects of excessive energy use also have an impact on an uncertain climate, and can lead to an increase in global temperatures. Controlling the use of electrical energy needs to be done in an effort to save energy. Efforts to save electricity can be started from controlling the use of electricity in street lighting. Control efforts are carried out by holding community training on the application of automatic light control to be applied to public street lighting. The training includes counseling on the importance of saving electrical energy, introduction to lighting automation systems, introduction to supporting components and assembling automatic lamp control devices. That way, people are able to reduce their consumption of electrical energy by implementing an automatic light control system for street lighting.

The outbreak of COVID-19 has resulted in a shift in economic and social conditions. Most of the electrical energy use is in buildings or dwellings near utility facilities. Therefore, this paper presents a case study of electrical energy use in Mueang Phetchaburi district, Phetchaburi province, Thailand, to study the behavior of electrical energy consumption changes during the COVID-19 pandemic. COVID-19 affects everyday life, such as rapidly decreased and increased electrical energy consumption in some areas. In this paper, the application of geographic information system (GIS) and python programming has been proposed and applied in spatial energy analysis. The results show that the total electrical energy consumption is decreased by approximately 24.48%, and the electrical energy consumption is significantly decreased in the medium business sectors. Whereas, the electrical energy consumption is slightly increased in the residential and commercial sectors. Moreover, the changes in patterns and behaviors of electrical energy uses and how the electrical energy flow affects urban areas can be understood easily.

Numerical study of fog formation around ambient air vaporizers

The use of electrical energy that is often encountered in households is leaving the house with the lights on, leaving electronic goods stuck in the socket, charging cell phones overnight and turning on the air conditioner when no one is around. This unwise behavior will result in a high increase in the use of electrical energy. To reduce this unwise behavior, a device will be made that functions as a switch to cut off electrical energy automatically when we leave the room. This tool uses an Arduino Uno microcontroller with a Passive Infrared Receiver sensor to flow electrical energy when we enter the room and cut off electrical energy when leaving the room. It can be concluded that the use of an automatic switch can reduce electrical energy consumption. Automatic switches with a delay of 20 seconds compared to conventional switches have a significant ratio of electrical energy consumption as indicated by the test results of a multiple ratio of 0.00 with a test level of less than 0.05. Using an automatic switch with a 20 second delay results in savings in electrical energy consumption of 48.76% of the electrical energy consumption using conventional switches.

Ambient air vaporizers (AVVs) are the most commonly used type of heat exchanger for cryogenic regasification stations. The transfer of heat from the environment for heating the liquefied gas and its vaporization is a cost-free and efficient method. Designing ambient air vaporizers for regasification or fueling stations requires accepting the size and related thermal power of the AVV considering the operating conditions and the type of liquefied gases to be vaporized. The nominal capacity of the ambient air vaporizer depends on its design, the frosting of longitudinal finned tubes, and the airflow through the vaporizer structure. This paper presents the results of experimental studies and computational fluid dynamics (CFD) analysis on determining the heat output of AVV longitudinal finned tubes depending on their design. This experiment was conducted in order to establish a numerical model. The relation between the longitudinal finned tubes thermal power and the air flow velocity is demonstrated and the beneficial effect of forced convection is proved. The obtained results are used for verification calculations of ambient air vaporizers’ performance depending on the size of the AVV, the profile cross-section, and the airflow velocity for different liquefied gases. Under conditions of forced convection, profiles with 12 equal-height fins were discovered to be the most efficient for higher airflow velocity providing up to 7% higher heat rate than profiles with 8 equal-height fins. However, at low air velocity, profiles with 8 equal-length fins showed a comparable heat output to profiles with 12 equal-length fins. Profiles with 8 and 12 unequal high fins differ in average heat output by about 28%. The profile with 12 unequal high fins turned out to be the least effective when 2D airflow was considered in this analysis.

India’s electrical energy situation has been diverse always. From conventional electrical energy use to non-conventional electrical energy use, from renewable electrical energy use to non-renewable electrical energy use, India has used its potential in every from of electrical energy sector, and tries to generate more electrical energy to satisfy the required demand. From 2019 to 2020, there was a sudden discontinuation in electrical energy generation in India because of the worldwide Covid 19 pandemic situation that resulted in lockdown and closing of schools, colleges, factories, transport and many other sectors that requires electricity. This reduced demand resulted in reduced electrical energy generation. This paper provide an overview over the electrical energy situation in 2019, 2020 pandemic situation, its recovery after 2020 and current electrical energy situation.

The ambient air vaporizer (AAV) technology is a promising option for vaporization of cryogenic fluids including liquefied natural gas (LNG). In this study, the heat transfer between ambient air and cryogenic LNG under supercritical conditions has been studied by using computational fluid dynamics (CFD). The process of regasification was first analyzed from the thermodynamics standpoint. In the absence of actual data for LNG, the empirical correlations and experimental data for supercritical flows of water and carbon dioxide were used to validate the CFD model. The model was then used to investigate the supercritical flow of LNG inside AAV. Operating conditions such as air flow velocity and operating pressure were studied. Furthermore, optimization of fin configurations including the number of fins, fin length, and fin thickness was also investigated. The methodology and results discussed in this study are of critical importance for designing AAV.

The problem encountered on the regasification terminal is unsteady operating because of unloading from LNG carrier to storage and holding mode that involves the on-off operation of Ambient Air Vaporizer (AAV) caused by frosting. The purposes of this study are to simulate a dynamic operation of small-scale regasification terminal using AAV with and without controls by process simulator UniSim. The result of the simulation without controls, shows that the gas flow rate has deviated 14% from the target, after 4 hours of operation output gas temperature is below 2.5°C, it cannot meet the requirements of the gas power plant. For simulation with controls, a digital on-off type controller is used for pump during unloading and switch or on-off between AAV, while PI type controller is used to control LNG flow rates. For the digital on-off controller, the controller is set to stop the unloading process when the remaining LNG in the carrier is 10% (350m3) and the other digital on-off controller will be set to act on switching AAV when the AAV gas sent out temperature reaches 3°C. For PI controllers, the tuning parameters to regulate the flow rate is Kc = 0.00638 and Ti = 0.00043. The maximum operating time for 1 AAV is 5 hours 15 minutes before it will be switched for defrosting and replaced with other AAV. After the controller installed, the gas sent out specifications from the terminal able to meet the requirements of the power plant, a molar flow rate of 6.53 MMSCFD and a minimum gas temperature of 2.5°C throughout the operating time.

The consumption of electrical energy from year to year continues to increase. This is caused by the use of electrical energy and electrical equipment that inefficient. Hence, it is necessary to make efforts to save electricity efficiently. One of the efforts that have been made is research on the PPC (Programmable Power Controller) which functions as a controller for the use of electrical energy in the AC (Air Conditioner) device. Optimization of AC is also an effort to save electrical energy. This research focuses on technological efforts in the form of a room condition monitoring system design (temperature and humidity monitoring), AC mode setting scenarios, and room characterization for efficient use of electrical energy using the WSN (Wireless Sensor Network) method. The performance of the WSN sensor node as a monitoring device for room conditions which includes temperature and humidity has been successfully created using a temperature sensor, humidity sensor, signal conditioning circuit, and a programmed microcontroller. WSN sensor node results show that the DHT21 temperature and humidity sensor, which has a temperature range is 15°C-90°C, minimum humidity of 20% RH, and a maximum of 90% RH, testing works well. Meanwhile, the average time needed to carry out the node selection process until it is connected to the selected node when there is a default node, and no default node is 9.068 seconds and 9.968 seconds. Moreover, the implementation result of this device in the room area is in general, during working hours from 09:00 to 17:00, humidity conditions range from 30% - 75%, and temperatures range from 20°C - 40°C close to normal limits according to ASHRAE standard 55. In the next research, we focus on using the WSN relay to completely aim the function of the WSN sensor as a tool to reduce the electrical energy for monitoring and controlling the temperature and humidity AC.

Electrical energy consumption in the opencast coal mine is very high. Electric shovels, pumps and coal handling plants consume 75% of the total electricity consumption of an opencast coal mine. In this paper, a modelling framework has been developed for electrical energy use benchmarking (internal as well as cross-sectional) of the mine. To develop a mine specific model for benchmarking electrical energy use statistical approach (linear regression method) has been applied. Specific power consumption (SPC) is used as a benchmarking index to assess the operating energy performance of a specific mine and multiple coal mines of India based on the field studies. Seasonal analysis of the electrical energy usage has also been analysed. Our results show the benchmark SPC as 0.50 kWh/t and the energy-saving potential as 10.7% for a single mine and the benchmark SPC of multiple coal mines as 0.52 kWh/t. The result concludes that SPC widely depends on its capacity and mining method and the developed model are useful for benchmarking and targeting for efficient electrical energy use in opencast mine.

Thermal resistance analysis of cryogenic frosting and its effect on performance of LNG ambient air vaporizer

Suitability of part block switching of ambient air vaporizer for propane vaporization in contrast to cryogenic vaporization

Conjugate numerical analysis on bundle effects for integrated heat transfer of LNG ambient air vaporizer

China’s LNG import volume in 2021 reached 121.356 million tons, which makes China the largest importer in the world. The ambient air vaporizer (AAV) for LNG vaporization is an ideal selection for minimizing the average monetary value of terminals and maximizing operating efficiency. However, the heat and mass transfer performance of real multi-component LNG is not the same as that of the pure component in AAV; what is more, deep cryogenic and multi-component characteristics of LNG could lead to the deterioration of heat-transfer performance, which may cause catastrophic consequences. Thus, this difficulty should be concerning and solved in its operation. Based on the law of conservation of energy and mass, a heat and mass transfer model was established that can calculate the coupled heat transfer from the LNG to the air-side of the AAV along its own length. Empirical correlations are proposed to predict some basic properties of the frost layer at the outside of the tube, where the internal fluid is seen as a pure component and a multi-component. The numerical results show that the root–mean–square error (RMS) of the frost thickness is 0.749 mm, and the RMS of the outlet fluid temperature is 2.06 K and 2.21 K in summer and winter, respectively. That is in good agreement with the experimental data in the previous literature. The results show that the length of the finned tube in the AAV affected by pure CH4 was increased by 42.5%; therefore, we recommend shortening the finned tube on the basis of safety to save costs. Compared to the pure components reference experiments, when the CH4 content of multi-component in five regions was 78.48–96.91%, it is found that the different varieties of thermodynamic dryness degree x within the two types of components is the key point for the distinct mechanisms of the heat transfer characteristics of the AAV. Additionally, compared to changing the design pressure and flow rate, it is found that varying the flow rate has a much greater impact on the heat and mass transfer performance of the AAV than changing its pressure. The calculation of the coupled heat and mass transfer of the AAV can provide a theoretical basis for subsequent engineering designs.

Liquefied natural gas (LNG) ambient air vaporizer (AAV) has attracted more attention because of its economy, popularity, and environmental protection; however, the low efficiency of AAV is the bottle-neck of its wide application. In order to find the effective methods of solving this problem, we proposed a mathematical model to evaluate the thermal resistances of LNG AAV. Besides, a thorough comparison of different correlations for natural convection and flow boiling is conducted. The results indicate that: (1) Obvious deviations are found between various heat transfer correlations. (2) The total thermal resistance of AAV increases with operation time. (3) The airside thermal resistance accounts for more than 90% of the total thermal resistance, and the percentage of frost thermal resistance is higher than 50% after 8 hours. (4) When air temperature is higher or lower than a transition temperature, the heat transfer performance of AAV enhances.