scholarly journals Observation of Circulation of Immiscible Mineral Lubricant Oil in an Air-Conditioning Machine Charged with HFC Refrigerant

2009 ◽  
Vol 4 (1) ◽  
pp. 47-56
Author(s):  
Makoto GOTO ◽  
Koji TANIFUJI ◽  
Masahiro FUJITA ◽  
Tomohiro YAMAUCHI ◽  
Satoshi OHUCHIDA ◽  
...  
2007 ◽  
Vol 73 (725) ◽  
pp. 291-297 ◽  
Author(s):  
Makoto GOTO ◽  
Koji TANIFUJI ◽  
Masahiro FUJITA ◽  
Tomohiro YAMAUCHI ◽  
Satoshi OHUCHIDA ◽  
...  

2014 ◽  
Vol 69 (6) ◽  
Author(s):  
Mohammed Hassan Jabal ◽  
Farid Nasir Ani ◽  
S. Syahrullail

Vegetable oils are sustainable fluids which have been promoted to replace petroleum-based oils due to its environment friendly characteristics; it is being a very important supply of biolubricant. The excellent advantage of vegetable oil is the fact it is really which can be used environment friendly supplier. In addition, vegetable oil based lubricant clearly show the possibility to minimize carbon monoxide also hydrocarbon emissions when used in IC engines. There are basically two different ways to using vegetable oil to be a bio-lubricant, either one by directly use the pure vegetable oil with additives or use certain blending ratio of vegetable oil with mineral lubricant. In this paper, the influences of the blending ratio of mineral oil with RBD palm olein on the tribological characteristics were investigated and compared with commercial lubricant oil by using the four ball tribotester. The blending ratio was varied from neat with interval of 20% by volume. All experimental works were conforming to ASTM D4172. The results exhibited that the blend of RBD palm olein with commercial lubricant oil has lower the wear scar of ball bearings and coefficient of friction compared to commercial lubricant oil. As a conclusion, the blending of RBD palm olein with commercial lubricant oil has better performance compared to commercial lubricant oil or pure RBD palm olein.


2009 ◽  
Vol 52 (5) ◽  
pp. 1285-1290 ◽  
Author(s):  
Paulo Renato Matos Lopes ◽  
Ederio Dino Bidoia

The aim of this work was to study the biodegradation of different types of automotive lubricant oils adapted to the aqueous medium using a base inoculum and an aqueous inoculum. Four treatments were carried out in two consecutive and similar experiments: T1 (control); T2 (half-synthetic oil); T3 (mineral oil); T4 (used oil). The results showed the following decreasing order of CO2 production in the Bartha and Pramer respirometers: T4 > T2 > T3 > T1. Thus, the used lubricant oil showed with highest biodegradability, followed by the half-synthetic one and the mineral oil. It was also observed that the mineral lubricant presented a longer period of adaptation compared to the half-synthetic one.


Author(s):  
Akira Kaneko ◽  
Masafumi Katsuta ◽  
Takahiro Oshiro ◽  
Sangchul Bae ◽  
Shunji Komatsu ◽  
...  

In previous research, we have been focusing on the performance of the each element heat transfer and hydraulic performance of refrigeration cycle. Experimental investigations have been repeated several times, and finally, we have substantial database including the effect of lubricant oil. Moreover, the maldistribution of two-phase in an evaporator can be also predicted from the experimental database. Under these circumstances, this study is intended to effectively put the construction of an automotive CO2 air conditioning system into practical design use through the simulation using the above-mentioned database. This paper describes the refrigeration cycle performance prediction of each element (e.g., an evaporator, a gas-cooler, and so on) by a simulation using substantial database and various available correlations proposed by us and several other researchers. In the performance prediction model of heat exchangers, local heat transfer and flow characteristics are considered and, in addition, the effects of lubricant oil on heat transfer and pressure drop are duly considered. The comparison is also made between simulation results and bench test results using a real automotive air conditioning system. Finally, the developed simulation method can predict the cooling capacity successfully within ±10% for A/C system simulation. By incorporating the lubricant oil effect, the simulation results are improved to ±5% and ±15% for the cooling capacity and pressure drop for evaporator simulation, respectively.


2010 ◽  
Vol 24 (5) ◽  
pp. 3285-3291 ◽  
Author(s):  
Maria Alexsandra de Sousa Rios ◽  
Sarah Nascimento Santiago ◽  
Ada Amélia Sanders Lopes ◽  
Selma Elaine Mazzetto

Author(s):  
Masafumi Katsuta ◽  
Takahiro Oshiro ◽  
Akira Kaneko ◽  
Sangchul Bae ◽  
Shunji Komatsu ◽  
...  

In previous researches, we have been focusing on the performance of the each element heat transfer and hydraulic performance of refrigeration cycle. Experimental investigations have been repeated several times and, finally, we have substantial data base including the effect of lubricant oil. Moreover, the mal-distribution of two-phase in an evaporator can be also predicted from the experimental data base. Under these circumstances, this study is intended to effectively put the construction of an automotive CO2 air conditioning system into practical design use through the simulation using the above-mentioned data base. This paper describes the refrigeration cycle performance prediction of each element (e.g. an evaporator, a gas-cooler, and so on) by a simulation using substantial data base and various available correlations proposed by us and several other researchers. In the performance prediction model of heat exchangers, local heat transfer and flow characteristics are considered and in addition, the effects of lubricant oil on heat transfer and pressure drop are duly considered. The comparison is also made between simulation results and bench test results using a real automotive air conditioning system. Finally, the developed simulation method can predict the cooling ability successfully within ±5%. By incorporating the lubricant oil effect, the simulation results are improved to ±5% and ±15% for the cooling ability and pressure drop respectively.


2019 ◽  
pp. 53-65
Author(s):  
Renata Domingos ◽  
Emeli Guarda ◽  
Elaise Gabriel ◽  
João Sanches

In the last decades, many studies have shown ample evidence that the existence of trees and vegetation around buildings can contribute to reduce the demand for energy by cooling and heating. The use of green areas in the urban environment as an effective strategy in reducing the cooling load of buildings has attracted much attention, though there is a lack of quantitative actions to apply the general idea to a specific building or location. Due to the large-scale construction of high buildings, large amounts of solar radiation are reflected and stored in the canyons of the streets. This causes higher air temperature and surface temperature in city areas compared to the rural environment and, consequently, deteriorates the urban heat island effect. The constant high temperatures lead to more air conditioning demand time, which results in a significant increase in building energy consumption. In general, the shade of the trees reduces the building energy demand for air conditioning, reducing solar radiation on the walls and roofs. The increase of urban green spaces has been extensively accepted as effective in mitigating the effects of heat island and reducing energy use in buildings. However, by influencing temperatures, especially extreme, it is likely that trees also affect human health, an important economic variable of interest. Since human behavior has a major influence on maintaining environmental quality, today's urban problems such as air and water pollution, floods, excessive noise, cause serious damage to the physical and mental health of the population. By minimizing these problems, vegetation (especially trees) is generally known to provide a range of ecosystem services such as rainwater reduction, air pollution mitigation, noise reduction, etc. This study focuses on the functions of temperature regulation, improvement of external thermal comfort and cooling energy reduction, so it aims to evaluate the influence of trees on the energy consumption of a house in the mid-western Brazil, located at latitude 15 ° S, in the center of South America. The methodology adopted was computer simulation, analyzing two scenarios that deal with issues such as the influence of vegetation and tree shade on the energy consumption of a building. In this way, the methodological procedures were divided into three stages: climatic contextualization of the study region; definition of a basic dwelling, of the thermophysical properties; computational simulation for quantification of energy consumption for the four facade orientations. The results show that the façades orientated to north, east and south, without the insertion of arboreal shading, obtained higher values of annual energy consumption. With the adoption of shading, the facades obtained a consumption reduction of around 7,4%. It is concluded that shading vegetation can bring significant climatic contribution to the interior of built environments and, consequently, reduction in energy consumption, promoting improvements in the thermal comfort conditions of users.


Author(s):  
Fremmy Raymond Agustinus

Desain penyejuk udara juga dapat diterapkan di bidang kesehatan, dengan standar Cleanroom dapat diperoleh suhu, kelembaban, kenyamanan dan kebersihan yang dibutuhkan untuk ruang steril (ruang bedah). Perancangan pendingin udara dalam hal ini dilakukan dengan menentukan beban pendinginan yang diperlukan untuk ruang steril (ruang bedah), kemudian menentukan ukuran ducting, jalur ducting, dan jumlah penggunaan ducting. Desain ini menggabungkan unit split saluran yang dimodifikasi, kipas booster, filter pra, filter medium, dan filter HEPA dengan menggunakan saluran aluminium preinsulated sebagai saluran udara. Desain dilakukan dengan menggunakan perangkat lunak AutoCAD 2012, Design Tools Duct Sizer, dan Microsoft Excel. Dari hasil perhitungan dan desain didapatkan kebutuhan kapasitas 3 ruang bedah yaitu ducted ducted 100.000 BTUH sebanyak 3 unit, booster fan 3.3 - 4 Di WG sebanyak 3 unit, pre filter 24 "x 24" x 2 "6 set, filter menengah 610 x 610 x 290 mm 6 set, dan filter HEPA 1220 x 610 x 70 mm 12. Untuk ruang steril, tekanan statis yang dihasilkan oleh unit pendingin harus lebih besar daripada tekanan statis yang dihasilkan dari unit yang ada. di ruang semi steril. Dengan kata lain, ruang steril harus memiliki tekanan positif terhadap ruang semi steril. Hal ini dimaksudkan agar udara di ruang semi steril tidak masuk ke ruang steril ketika pintu antar ruangan dibuka. Desain dan perhitungan ruang bedah, suhu nyata yang diperoleh adalah 23 ° C ± 2 ° C dan kelembaban relatif yang diperoleh adalah 60% ± 2%.   Air conditioning design can also be applied in the health field, with cleanroom standard can be obtained temperature, humidity, comfort and hygiene needed for sterile room (surgical room). The design of air conditioning in this case is done by determining the cooling load required for the sterile room (surgical room), then determining the ducting size, ducting path, and the amount of ducting usage. This design combines modified ducted split unit, booster fan, pre filter, medium filter, and HEPA filter by using preinsulated aluminum duct as an air passage. The design is done by using AutoCAD 2012 software, Design Tools Duct Sizer, and Microsoft Excel. From the calculation and design result obtained the capacity requirement of 3 surgical room that is split ducted 100.000 BTUH as many as 3 units, booster fan 3.3 - 4 In WG as many as 3 units, pre filter 24"x 24" x 2" 6 sets, medium filter 610 x 610 x 290 mm 6 sets, and HEPA filter 1220 x 610 x 70 mm 12 sets. For the sterile room, the static pressure generated by the cooling unit shall be larger than the static pressure generated from the unit present in the semi sterile room. In other words, the sterile room must have positive pressure to the semi sterile room. It is intended that the air in the semi sterile room does not enter into the sterile room when the door between room opened. In this surgical room design and calculation, real temperature obtained is 23 °C ± 2 °C and the relative moisture obtained is 60% ± 2%.


2019 ◽  
Vol 6 (3) ◽  
pp. 80-85
Author(s):  
Denis Igorevich Smagin ◽  
Konstantin Igorevich Starostin ◽  
Roman Sergeevich Savelyev ◽  
Anatoly Anatolyevich Satin ◽  
Anastasiya Romanovna Neveshkina ◽  
...  

One of the ways to achieve safety and comfort is to improve on-board air conditioning systems.The use of air cooling machine determines the air pressure high level at the point of selection from the aircraft engine compressor. Because of the aircraft operation in different modes and especially in the modes of small gas engines, deliberately high stages of selection have to be used for ensuring proper operation of the refrigeration machine in the modes of the aircraft small gas engines. Into force of this, most modes of aircraft operation have to throttle the pressure of the selected stage of selection, which, together with the low efficiency of the air cycle cooling system, makes the currently used air conditioning systems energy inefficient.A key feature of the architecture without air extraction from the main engines compressors is the use of electric drive compressors as a source of compressed air.A comparative analysis of competing variants of on-board air conditioning system without air extraction from engines for longrange aircraft projects was performed at the Moscow Aviation Institute (National Research University).The article deals with the main approaches to the decision-making process on the appearance of a promising aircraft on-board air conditioning system at the stage of its conceptual design and formulated the basic requirements for the structure of a complex criterion at different life cycle stages.The level of technical and technological risk, together with a larger installation weight, will require significant costs for development, testing, debugging and subsequent implementation, but at the same time on-board air conditioning system scheme without air extraction from the engines will achieve a significant increase in fuel efficiency at the level of the entire aircraft.


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