Natural Energy Utilization Research Articles

Numerical investigation of heat transfer characteristics of supercritical CO2 and water flow in 2D self-affine rough fractures

In recent years, efforts to maximize natural energy utilization have focused on harnessing energy from hot dry rocks (HDR) using supercritical carbon dioxide (SCCO2) or water as the heat transfer fluid. This study aims to enhance comprehension and evaluate the heat extraction performance of enhanced geothermal systems (EGS) by exploring the influence of various inlet velocities and fracture widths on the flow and heat transfer of SCCO2 and water within a rough single fracture in granite. This study utilized a 2D self-affine fractal function to create a rough-fractured rock with fractal properties in a φ50 × 100 mm granite sample. Investigating under 8 MPa conditions, we employed the thermophysical properties of SCCO2 and water to analyze the flow and heat transfer characteristics within the rough rock fractures. The results indicate the following: (1) Higher inlet velocities and wider fracture widths result in a broader temperature reduction range within the surrounding rock matrix for both SCCO2 and water. (2) Increasing the inlet flow velocity of SCCO2 and water leads to wider fracture widths, resulting in lower temperatures at the outlet end of the fracture. As the inlet flow velocity increases from 0.01 m/s to 0.04 m/s, the rate of temperature increase at the outlet can reach up to 19.8 % compared to water. (3) SCCO2, unlike water, exhibits significant reverse vortices at locations where the fracture surface morphology experiences substantial fluctuations. This behavior may be an indirect consequence of SCCO2’s higher velocity, with the direct cause being SCCO2’s lower viscosity and density than water. (4) Among the four conventional fluid thermodynamic parameters, specific heat capacity has the most significant impact on total energy flux rate (TEFR).

Comprehensive Study of Development Strategies for High-Pressure, Low-Permeability Reservoirs

Currently, there is no well-established framework for studying development patterns in high-pressure, low-permeability reservoirs. The key factors influencing development effect typically include the reservoir properties, well pattern, well spacing, and the rate of oil production. Reservoir A is a representative of this type of reservoir. Starting from its physical properties, a study of the development mechanism was conducted using the tNavigator (22.1) software. A total of 168 sets of numerical experiments were conducted, and 3D maps were innovatively created to optimize the development mode. Building upon the preferred mode, an exploration was carried out for the applicability of gas flooding and the optimization of water flooding schemes for such reservoirs. All experimental results were reasonably validated through Reservoir A. Furthermore, due to the high original pressure in such reservoirs, the injection of displacement media was challenging. Considering economic benefits simultaneously, a study was conducted to explore the rational utilization of natural energy. The research proved that for a reservoir with a permeability of about 10 mD, the suitable development scheme was five-point well pattern, a well spacing of 350 m, water–gas alternating flooding, and an initial oil production rate of 2%. When the reservoir underwent 8 months of depleted development, corresponding to a reduction in the reservoir pressure coefficient to 1.09, the development efficiency was relatively favorable. Over a 15-year production period, the oil recovery reached 29.98%, the water cut was 10.31%, and the reservoir pressure was maintained at around 67.18%. The geology of the newly discovered reservoir is not specific in the early stage of oilfield construction, and this research can help to determine a suitable development scheme.

The effect of geometry and location of balconies on single-sided natural ventilation in high-rise buildings

The demand for housing and the expansion of urbanization have increased the price of land and vertical growth of buildings, resulting in converting the courtyard and porch to balconies. Nowadays, semi-open spaces, which play a critical role in providing optimal indoor air and thermal conditions, are neglected. In addition, the area of such spaces is regarded as limited and sometimes even the balcony is eliminated, leading to improper thermal behavior and increased energy consumption, while such elements can be used for better natural ventilation of spaces and utilization of natural energy, resulting in reducing energy consumption in addition to controlling the pressure created by the wind in the case of correct design. The purpose of the current paper is to evaluate the performance of balconies on the high-rise buildings using single-sided ventilation in the harsh hot-arid climate of Hamdan in Iran, which there has not been studied already A general basic model is presented according to field studies and criteria. Field survey indicates that most of the high-rise buildings in Hamedan have single-sided natural ventilation, as well as are located on the south side, have a rectangular shape, are enclosed on three sides, and have recessed balconies. Based on the climate data of Hamedan, July is considered the hottest month of the year, during which natural ventilation should be applied. Simulation is conducted by computational fluid dynamics (CFD) method and ANSYS software. Based on the results, 4.5 m width and 1.5 m depth are regarded as the best geometry of the balcony for Hamedan providing a mass flow rate up to 1.38 kg/s. In addition, the position of the balcony in the wall of the building should not be symmetrical. The usage of a balcony in the middle of the façade could provide higher ventilation rate and reduce cooling energy up to 7% compared with the base case. Through a meticulous balcony design, wind could path through the larger spaces then it is led towards the opposite window, and finally exits the building in a single-sided ventilation mode. This causes the air to flow in most of the interior spaces, leading to better ventilation than other methods.

Core-sheath phase change fibers via coaxial wet spinning for solar energy active storage

Using phase change fibers (PCFs) will help buffer the changes in ambient temperature, improve the utilization of natural energy, and ease the energy crisis. However, the poor solar energy absorption efficiency and leakage of phase change materials from PCFs seriously impaired their performance in practical applications. In this work, the core-sheath structured composite PCFs with excellent temperature regulation capability and high energy storage capacity were prepared by an economical and efficient coaxial wet spinning process for the first time. The infrared absorbers, Cs0·33WO3 (CWO), were incorporated into the hollow thermoplastic polyurethane (TPU) fibers to enhance solar energy absorption, and the paraffin wax (PW) was infused into the cavity of the composite fibers, giving rise to the formation of composite PW@TPU/CWO PCFs. The resultant PCFs showed a decrease in molten enthalpy and crystal enthalpy with the increasing of CWO contents, and the PCFs of PW@TPU/CWO5 can maintain a molten enthalpy of up to 90.47 J/g and an encapsulation rate of 69.93% that were higher than almost previous reports. The simulated house model under the coverage of PCFs fabric exhibited slight temperature variation and change rate, demonstrating the excellent heat storage and regulation capability of the as-prepared PCFs. The results show great potential applications in solar energy storage, heat storage and temperature regulation areas.

PERANCANGAN PUSAT TEKNOLOGI & INFORMASI DI KABUPATEN TOJO UNA-UNA DENGAN PENDEKATAN SMART BUILDING

Information and technology center design as a place to communicate and interact with various SKPD/offices, information and technology development centers and shopping centers that aim to build social interaction between communities. The design of the information and technology center is carried out by applying the Smart Building approach. The Smart Building design concept is the utilization of natural energy and artificial energy. Energy efficiency in lighting and ventilation systems using the latest technological materials, which refer to structures, sensor systems and digitization. The design location is in Ampana City because it is the capital of the Tojo Una-una Regency, besides that it has an amazing and sustainable beach view. While the site is on Jl. Ahmad Yani, Dondo, Ampana Kota District, because it is very strategic according to the characteristics of this area. The shape of the Information and Technology Center in Tojo Una-Una Regency takes the Smart Building concept. Buildings that use smart building principles with a modern appearance are adapted to the building materials used and the responsibility of smart building materials to the local climate conditions.

Effect of thermo-physical parameters on heat transfer characteristics of the wall implanted with heat pipes

• A new evaluate index (ITRR) is proposed to reflect the thermal response. • The actual environmental of WIHP dynamic experiment system is tested and validation. • The influence of thermal conductivity on the heat transfer of WIHP is analyzed. • The influence of density on the heat transfer of WIHP is analyzed. • The influence of specific heat capacity on the heat transfer of WIHP is analyzed. The heat transfer characteristics of a wall implanted with heat pipes (WIHP), a new passive natural energy utilization technology, significantly differ from that of an ordinary wall. It features effective heat transfer between indoor and outdoor environments due to the pipe’s unidirectional thermal conductivity. The thermal performance of the wall is crucial in terms of reducing a building’s energy consumption. In this paper, the experiment and theoretical analysis were combined, and the numerical simulation calculation was used to analyze the effects of material thermo-physical parameters on WIHP heat transfer performance. The results show that for the inside surface temperature, density and specific heat capacity are negatively related to it, and thermal conductivity is also negatively related to it before the heat pipe is in optimum working condition, and then the thermal conductivity is positively related to it. For the inside surface heat flux, it is opposite to the variation of inside surface temperature. The inside surface temperature rise rate (ITRR) is proposed to reflect the thermal response of the inside surface temperature to the variation of outdoor air temperature. When the thermal conductivity increases, the difference between the maximum and minimum ITRR is 0.053 °C/h. When the density increases, the trend of ITRR decreases first and then increases, and the average value is 0.062 °C/h. When the specific heat capacity gradually increases, the difference between the maximum and minimum of ITRR is 0.006 °C/h.

Tight oil reservoir production characteristics developed by CO2 huff \u2018n\u2019 puff under well pattern conditions

Tight oil reservoirs have poor physical properties, and the problems including rapid oil rate decline and low oil recovery degree are quite common after volume fracturing. To obtain a general understanding of tight oil reservoir production improvement by CO2 huff ‘n’ puff, the high-pressure physical properties of typical tight oil samples are measured. Combining the typical reservoir parameters, the production characteristics of the tight oil reservoir developed by the CO2 huff ‘n’ puff are numerically studied on the basis of highly fitted experimental results. The results show that: (1) during the natural depletion stage, the oil production rate decreases rapidly and the oil recovery degree is low because of the decrease in oil displacement energy and the increase in fluid seepage resistance. (2) CO2 huff ‘n’ puff can improve the development effect of tight oil reservoirs by supplementing reservoir energy and improving oil mobility, but the development effect gradually worsens with increasing cycle number. (3) The earlier the CO2 injection timing is, the better the development effect of the tight reservoir is, but the less sufficient natural energy utilization is. When carrying out CO2 stimulation, full use should be made of the natural energy, and the appropriate injection timing should be determined by comprehensively considering the formation-saturation pressure difference and oil production rate. The research results are helpful for strengthening the understanding of the production characteristics of tight oil reservoirs developed by CO2 huff ‘n’ puff.

A Review of Ventilation and Environmental Control of Underground Spaces

Because of rapid urbanization, traffic problems, and other factors, underground spaces have been used more in the twenty-first century. Large underground spaces are required for underground city, metro, tunnel, mine, industrial and agricultural engineering, and civil air defense engineering. Underground spaces with varying thermal, ventilation, and lighting environments can face problems of comfort, health, and safety. High temperatures, high humidity, difficulty in flue gas emission, harmful microorganisms, radon, and physical and psychological problems are examples of issues. Air quality control technologies for underground spaces, such as ventilation, dehumidification, natural energy utilization, smoke extraction, and ventilation resistance reduction, are discussed. Ventilation for smoke-proofing/evacuation is also extensively addressed.

Green Pitch- Be the Part of Solution

Pursuing “Green” has become the new drive for organisations on the quest towards growth, competitiveness and global excellence. Environmental issues have gained importance in business as well as in public life throughout the world.Green dentistry is a part of strategy to promote our practise by employing environmental credibility. In growing concern of global warming, switching our practice over to green is the need of hour as it involves abundant utilization of natural energy and also produces large amount of biomedical waste at the same time, creating a huge environmental impact. We cannot deny the fact intelligence is the ability to adapt to change. This article speaks about the various concepts of how to go for eco-friendly dental practise.

Ventilation and environmental control of underground spaces: a short review

More and more underground spaces were used in 21st century because of rapid urbanization, traffic problems, etc. Underground city, metro, tunnel, mine, industrial and agriculture engineering, civil air defence engineering need large underground spaces. Underground spaces with different thermal, ventilation and lighting environments may cause comfort, health and safety problems. Concrete problems include excessive humidity, heat transfer specialty, excessive CO caused by blockage in long distance traffic tunnels, difficulty in smoke exhaust and evacuation during fire, harmful microorganism, radioactivity pollutants, psychological problems, and so forth. Air quality control technologies for underground spaces, including ventilation technology, dehumidification technology, natural energy utilization technology, smoke extraction technology and ventilation resistance reduction technology, will be reviewed. Ventilation for smoke-proof/evacuation and ventilation will also be reviewed.

Dynamic heat transfer characteristics of wall implanted with heat pipes in summer

The heat transfer characteristics of a wall implanted with heat pipes, a new passive natural energy utilization technology, significantly differ from that of an ordinary wall. A dynamic heat transfer model is established in this study via steady heat transfer experiment and theoretical analysis for the north wall implanted with heat pipes in summer months; relevant heat transfer characteristics are studied through dynamic simulation analysis. Results show that the inner temperature field of the north WIHP presents obvious upper and lower partitions in summer. The thermal response of the WIHP is faster than that of an ordinary wall. The delay time of the ordinary wall is higher than the WIHP by 1.38 h. The average temperature of the north WIHP is 2 °C lower than that of an ordinary wall, which represents an effective improvement to the indoor thermal environment. The accumulative heat transfer capacity of the north WIHP is relatively high, at 50.7 kW/m2

Analysis of Green Building Certification System for Developing G-SEED

G-SEED (Green Standard for Energy and Environmental Design) is operating in Korea as a certification system to evaluate the environmental friendliness of buildings. Buildings are generating loads such as carbon dioxide emission, energy consumption, the consumption of resources, destruction of natural ecosystem, change of global climate, pollution of indoor environment, and waste generation. For this purpose, a green building certification system has been introduced. In the green building certification system, evaluation of buildings through methods such as utilization of natural energy, adoption of energy saving system, rainwater management, etc., is induced to reduce environmental load. These certification systems are operated by each country. The level of the certification system is different according to the characteristics such as climate environment. BREEAM in the UK and LEED in the US are operating a version for international certification as well as domestic certification. In this study, analyze the certification system which operates the global version such as BREEAM, LEED. And to investigate the differences between domestic and international versions of each version of the certification system. Certification items classified as reflected by climate characteristics, national characteristics reflected items, general items, such as attempts to analyze the rating system. And certification items were grouped into general “Global certification items” having no specificity for locality and “Local certification items” that differ by each locality according to social, environmental, and political factors. Using the analysis results that comparison of LEED and BREEAM, the study then aims to ascertain the possibility of whether the G-SEED can be used to certify international buildings. And explore the possibility of developing international version of the G-SEED and indicate the direction of G-SEED amendments that may arise in the future. The study results would be available as basic data at the development of G-SEED for international version.

C-19 集合住宅における自然エネルギー利用手法に関する研究 : その3 サンルームの性能評価

C-19 集合住宅における自然エネルギー利用手法に関する研究 : その3 サンルームの性能評価

Assessment of Thermal Comfort in Institutional Building based on Theoretical and Experimental Analysis

Energy Management in buildings is a sound and respected engineering course. Careful use of energy and resources represents a technical, economical and ecological challenge as well as being one which is important for survival and which can only be mastered by highly qualified engineers. The main focus lies on the interaction between the building as a structure and the technical facilities. The main aim of my work is to utilize the natural thermal condition that exist presently in the building structure to a maximum by reducing the use of artificial thermal sources such as heaters, air conditioners etc. In this paper, I have considered 9 factors that influence the building structure as main factors. By analyzing these factors several possible solutions can be arrived for the utilization of natural energy instead of using artificial sources.

Sustainable Smart City: Masdar (UAE) (A City: Ecologically Balanced)

Background/Objectives: In future, billions of devices are going to connect to Future Internet (FI) to provide quality life to citizens. However energy sources for devices connection are limited. In this context, building Sustainable Smart Cities on natural energy resources is essential. Methods/Statistical Analysis: The data is collected from secondary sources i.e. online databases during the period of 2/12/2014-1/5/2015. Google search engine is used mainly for questing the articles. The data is in qualitative format including text, pictures, sound and videos. Since this article is based on exploratory study and case methodology, content analysis is done. Thematic coding is done grounded on the main keywords relating to smart cities dimensions. Findings: Main objectives of this research article are to see the sights of Smart Cities concepts. This article is also focusing on the state of art of Sustainable Masdar Smart City (UAE). As city’s name sounds “Masdar” which means “source” in Arabic, this city will be rich enough in renewable energy sources and sustainable buildings. The authors found that this Sustainable Smart City is completely energy efficient through solar. Furthermore, the authors discovered sustainable intelligent buildings of 1. IRENA’s Global Head Quarter. 2. Siemens Smart Building and 3. Masdar Institute of Science and Technology. City is designed completely based on ecofriendly of water, air and soil. Applications/Improvements: Sustainable Smart Cities are basically emphasize on optimum natural energy utilization in terms of solar, water, air and tidal. Soil and local materials are also place an important role in constitution of ecofriendly cities.

Formation of CuInSe2 Printable Solar Cell Using Aqueous Phase Synthesized CuIn Alloy Nanoparticles

Actualization of environmental problems has induced the utilization of natural energy, such as solar energy. On the other hand, it is true that minimum energy payback time of Si solar cell is long, and dramatic improvement of Si based solar battery’s efficiency is not easy since its efficiency come closed to theoretical value. Therefore, various type solar battery has vigorously researched Since CuInSe2 (CIS) based solar battery, one of the attractive solar cell materials, shows the maximum efficiency reached up to 20.9% and long life time at large scale modules, commercialization of CIS based solar battery is stimulated. However, it is also true that these cell are deposited in high vacuum condition, which lead the loss of natural resources and also energy. So, various researches were vigorously researched of chemical reduction method since it is ecological and also economical technique. Ye et al. synthesized Cu-In alloy particles by using chemical reduction method in organic solvent and the Cu-In alloy precursor films were transformed to CuInSe2 films by selenization [1]. The resulting cells demonstrate a maximum energy conversion efficiency of 3.92 %. However, total cost of this method is not low since organic solvent should be used. On the other hand, until now, we reported that the synthesis of uniform and well crystallized alloy nanoparticles, such as Pd20Te7 and also CuIn alloy nanoparticles by restrict controlling the homogenization of metallic complexes in the aqueous solution under room temperature [2]. In this method, reduction rate of the metal species can be controlled under the room temperature, nevertheless ternary, or more, alloy nano materials with uniform and well crystallized structure was not synthesized until now. Therefore, in this study, these Cu-In (CI) alloy precursor materials were applied to the synthesis of CIS printable solar cell. CI alloy nanoparticles were synthesized and size controlled by chemical reduction method under ambient conditions using metal chlorides as metal sources and sodium borohydride as a reducing agent. Dispersion of synthesized CI nanoparticles were printed onto Mo-sputtered glass substrates, and selenized at 575 ºC for 60min to form of CIS solar cells. By obeying the calculation results and also electrochemical potential measurement, CI nanoparticles can be successfully synthesized in aqueous solution under room temperature. After selenization, CI was transformed into CuInSe2 thin film solar cells. The CuInSe2 thin film solar cells synthesized by this method exhibited a photovoltaic conversion efficiency of 2.3% under AM 1.5 G illumination. From the relationship between open circuit potential, short circuit current density, and fill factor, it indicated that smoothing of CIS films and improvement of the crystallinity and thickness should need to increase the solar cells properties. This work has been supported by the Grant-in-Aid for Scientific Research (B) (No. 26281054). [1] Ye Seul Lim, et.,al, J. Phys. Chem. C, 2013, 117 (23), pp 11930–11940, [2] H. Takahashi et.,al, Applied Catalysis A: General 392 (2011) 80–85.

PASSIVE DESIGN TECHNIQUES APLIED TO GREEN BUILDINGS AS AN AESTHETIC AND SPATIAL DESIGN CONCEPT

1. INTRODUCTION The emergence of environmental problems as major social issues throughout the world has prompted sustainable development efforts in a wide range of areas, including industry, construction, and transportation, followed by the execution of numerous studies and policies. The concept of sustainable development has been dealt with in earnest in the construction field since the Declaration of Interdependence for a Sustainable Future at the 18th Chicago Convention of UIA in 1993. This Declaration included tasks to be implemented with respect to green buildings, such as the recycling of resources, application of energy-efficient designs, and utilization of natural energy in addition to the application of sustainable designs. As part of green building practices, countries around the world have been implementing various green building certification standards, such as LEED, GBCC, CASBEE, and BREEAM. These certification standards prescribe the criteria relating to the external environment, energy cons...

Case studies of the utilization of natural energy in the field of fisheries

Case studies of the utilization of natural energy in the field of fisheries

Assessment of Building Sustainable Performance Based on Set Pair Analysis (SPA)

How to evaluate building sustainable performance is a hot issue in the world, the paper combine the “natural energy”, “energy recycling” and “ energy consumption” with 12 indicators into a evaluation system, and then use the set pair analysis(SPA) methods to evaluate the building sustainable performance. Through the empirical analysis with 3 cases, the results show that increase the natural energy utilization and enhance the energy recycling can reduce energy consumption and improve the building sustainable performance. In addition, the SPA also can quantitative the evaluation results.

Evaluation of Building Sustainable Performance Based on Set Pair Analysis

How to evaluate building sustainable performance is a hot issue in the world, the paper combine the “natural energy”, “energy recycling” and “ energy consumption” with 12 indicators into a evaluation system, and then use the set pair analysis(SPA) methods to evaluate the building sustainable performance. Through the empirical analysis with 3 cases, the results show that increase the natural energy utilization and enhance the energy recycling can reduce energy consumption and improve the building sustainable performance. In addition, the SPA also can quantitative the evaluation results.