scholarly journals RESEARCHES ON THE TESTING IN LABORATORY CONDITIONS OF AN ECOLOGICAL CLIMATE SYSTEM USED FOR SELFPROPELED AGRICULTURAL MACHINES

2021 ◽  
pp. 391-398
Author(s):  
Iuliana Gageanu ◽  
Dan Cujbescu ◽  
Cristinel Dumitru
Keyword(s):  
Great Part ◽  
Water Evaporation ◽  
Evaporation Process ◽  
Air Conditioner ◽  
Mixing Process ◽  
Air Conditioners ◽  
Other Substances ◽  
Standards And Regulations ◽  
Maintenance Systems ◽  
Agricultural Machines

Nowadays, cooling the air by means of climate maintenance systems is achieved, in most cases, using installations based on freon or other substances that cause pollution. Taking into account the fact that the EEC standards and regulations increase the emphasis on ensuring the quality, labour safety, health and environment, finding a solution for air conditioners that do not use a substance that causes pollution, has become a necessity. As a great part of farming work is done in the warmest periods of the year, temperatures being frequently over 35oC, it is necessary to equip the agricultural machines with air conditioners in order to achieve a thermic comfort in the cab. For this purpose, an air conditioner based on the process of water evaporation was designed, made and tested. The installation is able to cool the air that enters into the cab through the evaporation process that takes place in the special filling, with an efficiency of the mixing process more than 90%. Air passing sections are calculated so that they can assure both the quantity needed for climate maintenance in the cab (about 3.5 - 4 m3/min) and the relative speed between air and water in the filling, in order for the evaporation process to be conducted in the best conditions that were theoretical established.

scholarly journals Optimal Air Conditioner Placement Using a Simple Thermal Environment Analysis Method for Continuous Large Spaces with Predominant Advection

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4663
Author(s):  
Tatsuhiro Yamamoto ◽  
Akihito Ozaki ◽  
Myonghyang Lee
Keyword(s):  
Air Conditioning ◽  
Thermal Environment ◽  
Fluid Dynamic ◽  
Optimal Placement ◽  
Air Conditioner ◽  
Analysis Method ◽  
Computational Fluid Dynamic Analysis ◽  
Environment Analysis ◽  
Air Conditioners ◽  
Energy Simulations

The number of houses with large, continuous spaces has increased recently. With improvements in insulation performance, it has become possible to efficiently air condition such spaces using a single air conditioner. However, the air conditioning efficiency depends on the placement of the air conditioner. The only way to determine the optimal placement of such air conditioners is to conduct an experiment or use computational fluid dynamic analysis. However, because the analysis is performed over a limited period, it is difficult to consider non-stationarity effects without using an energy simulation. Therefore, in this study, energy simulations and computational fluid dynamics analyses were coupled to develop a thermal environment analysis method that considers non-stationarity effects, and various air conditioner arrangements were investigated to demonstrate the applicability of the proposed method. The accuracy verification results generally followed the experimental results. A case study was conducted using the calculated boundary conditions, and the results showed that the placement of two air conditioners in the target experimental house could provide sufficient air conditioning during both winter and summer. Our results suggest that this method can be used to conduct preliminary studies if the necessary data are available during design or if an experimental house is used.

Solar Heat Underground Storage Based Air Conditioning Vis-à-Vis Conventional HVAC Experimental Validation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Carlos R. de Nardin ◽  
Felipe T. Fernandes ◽  
Adriano J. Longo ◽  
Luciano P. Lima ◽  
Felix A. Farret ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Heat Pumps ◽  
Conventional Heating ◽  
Management Technique ◽  
Air Conditioner ◽  
Heat Management ◽  
Air Conditioners ◽  
Solar Heat ◽  
Reduction Of Energy Consumption ◽  
The One

This paper presents a comparison of air conditioners using the conventional heating, ventilation, and air conditioning heat pumps and the one using solar heat stored underground, also known as shallow geothermal air conditioning. The proposed air conditioner with solar heat stored underground reunites practical data from an implementation of the heuristic perturb-and-observe (P&O) control and a heat management technique. The aim is to find out the best possible heat exchange between the room ambient and the underground soil heat to reduce its overall consumption without any heat pump. Comparative tests were conducted in two similar rooms, each one equipped with one of the two types of air conditioning. The room temperature with the conventional air conditioning was maintained as close as possible to the temperature of the test room with shallow geothermal conditioning to allow an acceptable data validation. The experiments made both in the winter of 2014 and in the summer of 2015 in Santa Maria, South Brazil, demonstrated that the conventional air conditioner consumed 19.08 kWh and the shallow geothermal conditioner (SGC) consumed only 4.65 kWh, therefore, representing a reduction of energy consumption of approximately 75%.

Analytical solution for soil water redistribution during evaporation process

2013 ◽  
Vol 68 (12) ◽  
pp. 2545-2551 ◽  
Author(s):  
Jidong Teng ◽  
Noriyuki Yasufuku ◽  
Qiang Liu ◽  
Shiyu Liu
Keyword(s):  
Analytical Solution ◽  
Water Content ◽  
Soil Water ◽  
Exponential Function ◽  
Experimental Result ◽  
Water Evaporation ◽  
Evaporation Process ◽  
Climate Control ◽  
Water Redistribution ◽  
Control Apparatus

Simulating the dynamics of soil water content and modeling soil water evaporation are critical for many environmental and agricultural strategies. The present study aims to develop an analytical solution to simulate soil water redistribution during the evaporation process. This analytical solution was derived utilizing an exponential function to describe the relation of hydraulic conductivity and water content on pressure head. The solution was obtained based on the initial condition of saturation and an exponential function to model the change of surface water content. Also, the evaporation experiments were conducted under a climate control apparatus to validate the theoretical development. Comparisons between the proposed analytical solution and experimental result are presented from the aspects of soil water redistribution, evaporative rate and cumulative evaporation. Their good agreement indicates that this analytical solution provides a reliable way to investigate the interaction of evaporation and soil water profile.

Performance evaluation and design considerations for a split air-conditioner with built-in thermal energy storage

2018 ◽  
Vol 40 (5) ◽  
pp. 560-575
Author(s):  
Jehanzeb Ahmad ◽  
M Najam Ul Islam ◽  
Jawwad Sabir
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Low Cost ◽  
Hvac Systems ◽  
Air Conditioner ◽  
Widespread Application ◽  
Air Conditioners

The benefits of thermal energy storage using phase change materials are well documented in the literature. Despite all the potential benefits of thermal energy storage, its commercial and widespread application remains limited. This is due to the high initial cost of phase change materials, extensive rework required in buildings, major modifications in HVAC systems, and the potential for leakage, fire and toxicity hazards. There is a strong need for a simple thermal energy storage solution which can be adopted by large number of consumers. Ductless split air-conditioners are portable, low cost, efficient and account for 70% of all air-conditioning systems sold worldwide each year. The present research provides a novel and low cost solution that incorporates thermal energy storage in these air conditioners, allowing them to run without electricity for 3 h. The paper deals with the detailed design aspects and engineering challenges that arise when incorporating thermal energy storage in these small units. A prototype air-conditioner with in-built thermal energy storage was developed, and all performance parameters presented have been validated through data obtained from the prototype. Our results indicate that thermal energy storage can be incorporated in split units in low cost and with minimal drop in overall energy efficiency of the system. Practical application: Incorporating thermal energy storage in split air-conditioners which enables them to run without grid for many hours has immense practical applications. Since around 50% power in any building is consumed by HVAC systems, being able to provide cooling during peak hours without using grid can significantly reduce load on the grid without compromising user comfort. For developing countries where load shedding is frequent, the users can run these air-conditioners without the use of generators or batteries thus saving costs and the environment.

scholarly journals KINERJA TERMAL SELUBUNG GEDUNG KULIAH KOTA BANDAR LAMPUNG ITERA

2019 ◽  
Vol 3 (3) ◽  
pp. 267
Author(s):  
Andi Asrul Sani ◽  
Adelia Enjelina Matondang ◽  
Guruh Kristiadi Kurniawan ◽  
Anggi Mardiyanto
Keyword(s):  
Heat Transfer ◽  
Energy Consumption ◽  
Building Energy ◽  
Air Conditioner ◽  
Tropical Country ◽  
Air Conditioners ◽  
Natural Lighting ◽  
Thermal Transfer ◽  
Institute Of Technology ◽  
Window Area

Abstract: The use of glass material should consider the comfort of space in the building. Field of glass is needed as natural lighting and visual facilities between the occupants and the surrounding environment. Its function as natural lighting is often accompanied by an increase in temperature in buildings, considering that Indonesia is a tropical country. Building temperatures that increase due to incoming sunlight can cause discomfort to building occupants. Such conditions make building occupants use air conditioner (AC). The use of air conditioners can increase the value of building energy consumption. For this reason, research on the value of heat transfer in buildings or the value of OTTV (Overall Thermal Transfer Value). OTTV value calculation is done by manual calculation. Bandar Lampung City lecture building at the Sumatra Institute of Technology was chosen as the object of this study. From the results of the study found that the value of heat transfer of a building or OTTV (Overall Thermal Transfer Value) is influenced by the factor of the ratio of the window area to the facade or WWR (Window Wall Ratio) and the shading factor (Shading Coefficient).(Keywords: Keyword: energy consumption, building energy, glass. Abstract: Penggunaan material kaca semestinya mempertimbangkan kenyamanan ruang dalam bangunan. Bidang kaca diperlukan sebagai pencahayaan alami dan sarana visual antara penghuni dan lingkungan sekitar. Fungsinya sebagai pencahayaan alami seringkali disertai dengan peningkatan temperatur pada bangunan, mengingat Indonesia merupakan negara yang beriklim tropis. Temperatur bangunan yang meningkat akibat dari radiasi sinar matahari yang masuk dapat menyebabkan ketidaknyamanan bagi penghuni bangunan. Kondisi seperti itu membuat penghuni bangunan menggunakan air conditioner (AC). Penggunaan air conditioner tersebut dapat meningkatkan nilai konsumsi energi bangunan. Untuk  itu dilakukan penelitian mengenai nilai perpindahan panas dalam bangunan atau nilai OTTV (Overall Thermal Transfer Value). Penghitungan nilai OTTV dilakukan dengan penghitungan manual. Gedung kuliah Kota Bandar Lampung di Institut Teknologi Sumatera di pilih sebagai objek dalam penelitian ini. Dari hasil penelitian ditemukan bahwa nilai perpindahan panas suatu bangunan atau OTTV (Overall Thermal Transfer Value) dipengaruhi oleh faktor nilai perbandingan luas jendela terhadap bidang fasad atau WWR (Window Wall Ratio) dan faktor pembayangan (Shading Coefficient).Kata kunci : konsumsi energi, energi bangunan, kaca.

scholarly journals The effect of a prototype hydromulch on soil water evaporation under controlled laboratory conditions

2020 ◽  
Vol 68 (4) ◽  
pp. 404-410
Author(s):  
Antoni M.C. Verdú ◽  
M. Teresa Mas ◽  
Ramon Josa ◽  
Marta Ginovart
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Time Course ◽  
Linear Models ◽  
Water Evaporation ◽  
Mechanical Resistance ◽  
Evaporation Process ◽  
Soil Columns ◽  
Dry Conditions

AbstractOrganic hydromulches can be an interesting alternative for weed control in perennial crops, but can also reduce soil water evaporation. To examine the effect of a hydromulch layer on soil water content in dry conditions laboratory experiments were conducted at constant 25°C, 40% air RH. Both for small soil containers with a short time course and for larger soil columns (with two sensors at depths of 6 cm and 11 cm) with a longer time course, the presence and also the thickness of hydromulch were significant factors for the temporal evolution of soil water content. Two distinct stages of the evaporation process, the first or initial stage and the last or final stage, were identified, analysed and compared for these experiments. General linear models performed on the soil water content temporal evolutions showed significant differences for the first and last stages at the top and bottom of the soil columns with and without hydromulch. Hydromulch application delayed the evaporation process in comparison with the control. Moreover, the hydromulch layer, which was tested for mechanical resistance to punching, offered enough resistance to prevent its perforation by the sprouts of weed rhizomes.

Psycho-physiological evaluations of low-level impulsive sounds produced by air conditioners

2021 ◽  
Vol 263 (5) ◽  
pp. 1186-1193
Author(s):  
Yoshiharu Soeta ◽  
Ei Onogawa
Keyword(s):  
Sound Pressure ◽  
Living Room ◽  
Air Conditioner ◽  
Regression Analyses ◽  
Noise Sources ◽  
Air Conditioners ◽  
Low Level ◽  
Subjective Loudness ◽  
Long Time

Air conditioners are widely used in buildings to maintain thermal comfort for long time. Air conditioners produce sounds during operation, and air conditioners are regarded as one of the main noise sources in buildings. Most sounds produced by the air conditioner do not fluctuate over time and sound quality of the steady sounds produced by the air conditioner have been evaluated. However, air conditioners sometimes produce low-level and impulsive sounds. Customers criticizes such sounds are annoying when they sleep and they spend time quietly in the living room. The aim of this study was to determine the factors that significantly influence the psycho-physiological response to the low-level impulsive sounds produced by air conditioners. We assessed the A-weighted equivalent continuous sound pressure level (LAeq) and factors extracted from the autocorrelation function (ACF). Subjective loudness, sharpness, annoyance, and electroencephalography (EEG) were evaluated. Multiple regression analyses were performed using a linear combination of LAeq, the ACF factors, and their standard deviations. The results indicated that LAeq, the delay time of the first maximum peak, the width of the first decay of the ACF, and the magnitude and width of the IACF could predict psycho-physiological responses to air conditioner sounds.

A photothermal and Fenton active MOF-based membrane for high-efficiency solar water evaporation and clean water production

2020 ◽  
Vol 8 (43) ◽  
pp. 22728-22735
Author(s):  
Xu Ma ◽  
Zheng Deng ◽  
Zhuoyi Li ◽  
Danke Chen ◽  
Xinyi Wan ◽  
...  
Keyword(s):  
High Efficiency ◽  
Water Evaporation ◽  
Contaminated Water ◽  
Clean Water ◽  
Evaporation Process ◽  
Water Production ◽  
Solar Water

A Fenton active Zr–Fc MOF-based membrane was designed for efficiently producing clean water from VOC contaminated water via the solar evaporation process.

scholarly journals Personal Atmosphere: Estimation of Air Conditioner Parameters for Personalizing Thermal Comfort

2020 ◽  
Vol 10 (22) ◽  
pp. 8067
Author(s):  
Tomohiro Mashita ◽  
Tetsuya Kanayama ◽  
Photchara Ratsamee
Keyword(s):  
Machine Learning ◽  
Thermal Comfort ◽  
Air Temperature ◽  
Fine Tuning ◽  
Air Conditioner ◽  
Data Set ◽  
Air Conditioning System ◽  
Air Conditioners ◽  
Uniform Distributions ◽  
Machine Learning Model

Air conditioners enable a comfortable environment for people in a variety of scenarios. However, in the case of a room with multiple people, the specific comfort for a particular person is highly dependent on their clothes, metabolism, preference, and so on, and the ideal conditions for each person in a room can conflict with each other. An ideal way to resolve these kinds of conflicts is an intelligent air conditioning system that can independently control air temperature and flow at different areas in a room and then produce thermal comfort for multiple users, which we define as the personal preference of air flow and temperature. In this paper, we propose Personal Atmosphere, a machine learning based method to obtain parameters of air conditioners which generate non-uniform distributions of air temperature and flow in a room. In this method, two dimensional air-temperature and -flow distributions in a room are used as input to a machine learning model. These inputs can be considered a summary of each user’s preference. Then the model outputs a parameter set for air conditioners in a given room. We utilized ResNet-50 as the model and generated a data set of air temperature and flow distributions using computational fluid dynamics (CFD) software. We then conducted evaluations with two rooms that have two and four air conditioners under the ceiling. We then confirmed that the estimated parameters of the air conditioners can generate air temperature and flow distributions close to those required in simulation. We also evaluated the performance of a ResNet-50 with fine tuning. This result shows that its learning time is significantly decreased, but performance is also decreased.

Sign in / Sign up

Export Citation Format

Share Document