scholarly journals Effect of Non-Condensable Gas Leakage on Long Term Cooling Performance of Loop Thermosyphon

2013 ◽  
Vol 03 (04) ◽  
pp. 131-135 ◽  
Author(s):  
Hiroyuki Toyoda ◽  
Yoshihiro Kondo
Keyword(s):  
Cooling Performance ◽  
Gas Leakage

Performance Stability of Recycle Amine-Free Water-Soluble Coolant in Long Term Operation

2014 ◽  
Vol 625 ◽  
pp. 530-535
Author(s):  
Kenji Yamaguchi ◽  
Yasuo Kondo ◽  
Satoshi Sakamoto ◽  
Mitsugu Yamaguchi ◽  
Ryoichi Nakazawa
Keyword(s):  
Environmental Effect ◽  
Free Water ◽  
Water Soluble ◽  
Water Recovery ◽  
Machining Processes ◽  
Cooling Performance ◽  
Recycling System ◽  
Term Operation ◽  
The Stability

Recently, the concern for the environment has been increasing rapidly. In machining processes, the treatment of water-soluble coolants waste has caused environmental problems. Water-soluble coolants contain surfactants, preservatives, and corrosion inhibitors for maintaining the stability and performance of the coolants. To reduce the management cost and environmental effect of water-soluble coolants, the authors have been studying a recycling system for water-soluble coolants. In the recycling system, oil-free recycle water is isolated from the coolant waste and reused as a diluent of the new coolant. The authors have been developing different types of water recovery methods for the recycling system, and the recovered water from the coolant waste has potential as a diluent for a new coolant. In this report, we focused on the amine (alkanolamine) -free water-soluble coolant. Some amine-free water-soluble coolants have been developed and are commercially available. A reduction in the environmental effect in the waste treatment of coolants is expected with amine-free coolants. We have demonstrated that the amine-free water-soluble coolant has equal or better cooling and lubricating performance compared with the conventional amine-containing coolant. In addition, the amine-free coolant shows good recyclability for the recycling system. The processing time of the recycling treatment of the amine-free coolant has been decreased by half with our recycling process compared with the conventional amine-containing coolant. In this report, we examined the stability, cooling performance and lubricating performance of the recycle amine-free water-soluble coolant in long term operation. The recycle amine-free water-soluble coolant is operated in a 3-axis machining center for several months. We observed concentration, pH, corrosion inhibition performance, cooling performance, and lubricating performance of the coolant. The results from these experiments show the amine-free water-soluble coolant has the advantage to use in the recycling system for water-soluble coolant.

scholarly journals Wearable thermoelectrics for personalized thermoregulation

2019 ◽  
Vol 5 (5) ◽  
pp. eaaw0536 ◽  
Author(s):  
Sahngki Hong ◽  
Yue Gu ◽  
Joon Kyo Seo ◽  
Joseph Wang ◽  
Ping Liu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Lower Energy ◽  
Coefficient Of Performance ◽  
Entire Space ◽  
Human Comfort ◽  
Cooling Performance ◽  
Cooling Technology ◽  
High Flexibility ◽  
Novel Design

Thermoregulation has substantial implications for energy consumption and human comfort and health. However, cooling technology has remained largely unchanged for more than a century and still relies on cooling the entire space regardless of the number of occupants. Personalized thermoregulation by thermoelectric devices (TEDs) can markedly reduce the cooling volume and meet individual cooling needs but has yet to be realized because of the lack of flexible TEDs with sustainable high cooling performance. Here, we demonstrate a wearable TED that can deliver more than 10°C cooling effect with a high coefficient of performance (COP > 1.5). Our TED is the first to achieve long-term active cooling with high flexibility, due to a novel design of double elastomer layers and high-ZT rigid TE pillars. Thermoregulation based on these devices may enable a shift from centralized cooling toward personalized cooling with the benefits of substantially lower energy consumption and improved human comfort.

scholarly journals Quantitative risk evaluation related to long term CO2 gas leakage along wells

2009 ◽  
Vol 1 (1) ◽  
pp. 3595-3602 ◽  
Author(s):  
Vincent MEYER ◽  
Emmanuel HOUDU ◽  
Olivier POUPARD ◽  
Jérome LE GOUEVEC
Keyword(s):  
Risk Evaluation ◽  
Co2 Gas ◽  
Gas Leakage

A Design for Loop Thermosyphon Including Effect of Non-Condensable Gas

2011 ◽  
Author(s):  
Hiroyuki Toyoda ◽  
Tadakatsu Nakajima ◽  
Yoshihiro Kondo ◽  
Akio Idei ◽  
Shigemasa Sato
Keyword(s):  
Thermal Resistance ◽  
Ambient Temperature ◽  
Partial Pressure ◽  
Total Pressure ◽  
Air Cooling ◽  
Total Thermal Resistance ◽  
Cooling Performance ◽  
Design Information ◽  
Cooling Part

We have developed a loop thermosyphon for cooling electronics devices. Its cooling performance changes with the ambient temperature and amount of input heating. Especially it deteriorates with non-condensable gas (NCG) increase. NCG leakage of thermosyphon cannot detect below under 10−10 Pa-m3/s, though we have to design the thermosyphon considering these characteristics to provide guaranteed performance for 5–10 years. In this study, the effect of the amount of NCG in each component of a thermosyphon was measured while changing the amount of heater input, and the amount of NCG. As a result, we obtained some useful design information. The performance of air cooling part does not depend on the NCG amount in this case. The performance of evaporation part depends on the total pressure that includes the partial pressure of vapor and the partial pressure of NCG. The performance of condensation part is deteriorated strongly by NCG amount increase. Additionally, we expressed these performances as approximations. These expressions let us predict the total thermal resistance of this thermosyphon by the NCG amount and the input heating amount. Then, using the leakage of a thermosyphon and the amount of dissolved NCG in water, we predicted the amount of NCG that will be in the thermosyphon after 10 years. These results also let us predict the thermosyphon’s total thermal resistance after 10 years. Though there is a slight leakage on thermosyphon, using this technique, we are able to design a thermosyphon that is guaranteed the cooling performance for a long term.

scholarly journals A New Mitigation Measure to Counter Thermal Instability of Air-Cooled Embankment in Sandy Permafrost Zones of Tibet Plateau

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Minghao Liu ◽  
Jing Luo ◽  
Liang Zhang ◽  
Xin Ju
Keyword(s):  
Cooling Capacity ◽  
Ground Temperature ◽  
Tibet Plateau ◽  
Crushed Rock ◽  
Transfer Model ◽  
Rock Layer ◽  
Cooling Performance ◽  
Permafrost Warming ◽  
Warm Permafrost

A crushed-rock revetment (CRR) with high permeability that can be paved on embankment slopes is widely used to cool and protect the subgrade permafrost. In this study, a traditional CRR over warm permafrost was selected to investigate its cooling characteristics based on the ground temperature observed from 2003 to 2014. A new mitigation structure (NMS) was designed to improve the cooling capacity of the CRR and to counter the pore-filling of the rock layer. Numerical simulations were conducted to evaluate the cooling performance and reinforcing capacity of the NMS based on a developed heat and mass transfer model. The results indicate that the traditional CRR can improve the symmetry of the permafrost subgrade and decrease the ground temperature of shallow permafrost. However, the CRR cannot generate strong enough cooling to influence the deep (below 10 m depth) and warm permafrost with a mean annual ground temperature above −1.0°C. The wind-blown sand can further weaken the cooling of the CRR and cause significant permafrost warming and thawing beneath the slopes, posing a severe threat to the long-term safe operation of the embankment. The proposed NMS can produce a significantly superior cooling performance to the CRR. If the CRR is reinforced by the new structure, it can not only effectively cool the underlying warm permafrost but also elevate the permafrost table. The new structure can also protect the rock layer on the slopes from sand-filling. The NMS can be used as an effective method for roadbed design or maintenance over warm permafrost.

scholarly journals Oil Pressure Monitoring for Sealing Failure Detection and Diagnosis of Power Transformer Bushing

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7908
Author(s):  
Jiansheng Li ◽  
Zhi Li ◽  
Judong Chen ◽  
Yifan Bie ◽  
Jun Jiang ◽  
...  
Keyword(s):  
Power Transformer ◽  
Failure Detection ◽  
Pressure Monitoring ◽  
Online Application ◽  
Gas Leakage ◽  
Bottom Valve ◽  
Temperature And Pressure ◽  
Detection And Diagnosis ◽  
Sealing Failure

Power transformer bushings withstand great electrical and mechanical stress during high voltage and high current working conditions. Sealing failure poses a great threat to the long-term and reliable operation of the bushing and power transformer; however, the criterion to evaluate the sealing status of a bushing caused by mechanical problems is still lacking. In this paper, a transformer bushing model is established to gain theoretical insight into the relationship between temperature and pressure of a compact multilayer bushing. To evaluate the bushing mechanical status, different sealing conditions are tested based on the temperature and pressure monitoring within the physical 110 kV bushing. The results show that mechanical sealing failure can be diagnosed when the fluctuation of the oil pressure value exceeds the theoretical curve in steady state by 3 kPa. With different reliability coefficients, gas leakage and oil leakage are available to be further determined. The primary and auxiliary criteria based on oil pressure and its gradient are proposed to evaluate comprehensively the actual sealing condition of the bushing, and a wireless oil pressure module is developed at the bottom valve, which is quite beneficial to field online application. It is promising to extend the online mechanical monitoring and diagnosis to oil-immersed power equipment.

Successful Barrier Enhancement Application of Epoxy Based Resin for Multiple Casing to Casing Annuli Having Tight Injectivity - Case Study from Saudi Arabian Peninsula

2021 ◽  
Author(s):  
Abdulmalek Shamsan ◽  
Alejandro De la Cruz ◽  
Walmy Jimenez
Keyword(s):  
Epoxy Resin ◽  
Gas Flow ◽  
Resin System ◽  
Gas Leakage ◽  
Well Integrity ◽  
Epoxy Resin System ◽  
Modified Surface ◽  
Flow Through ◽  
Tailored Design

Abstract This study describes the approach used for enhancing the well integrity that was compromised with gas flow through a casing-casing annulus (CCA). Extremely tight injectivity at a CCA demands a solid free solution which not only can be injected but also resist high differential pressures to provide a long-term barrier in CCA. In this paper a successful leak remediation using an epoxy resin system helped the operator save a well and restart its production. Several pressure tests were conducted for identifying an extremely tight casing leak which was causing formation gas travelling to surface through the annulus. This issue required the customer to look for an efficient remedial solution to seal off the gas leakage and regain productivity. Due to the extremely low injectivity, a conventional cement squeeze or any solid laden particle-based squeeze approach was prone to fail. Alternatively, a tailored solid free epoxy resin system was placed in the annulus using an unconventional placement technique resulted in barrier enhancement and helped the operator place the well back into production. For a mature well flowing through 7 × 9 5/8‑in. and 9 5/8 × 13 3/8‑in., a tailored epoxy-based resin system formulation was placed in the well bore with modified surface operations procedures which helped in eliminating current annular pressure to regain well integrity and production. Remedial operations were performed from the surface by squeezing to seal off the gas coming from the annulus. A Tailored design derived from rigorous lab testing and perfect field execution resulted in CCA pressure remediation in a single attempt of the treatment injection, proving that the concept of using a solids-free resin to enhance existing deteriorated barriers is a reliable method. This epoxy resin system helped the operator to regain the well integrity and production in the shortest time without expensive well intervention operations. Epoxy resin based systems have been identified as a novel solution to remediate barrier integrity for well construction and workover operations, hence such case histories with enhanced operations procedures are helpful in increasing awareness of the benefits that can be attained in challenging high-pressure, low-injectivity environments, and can improve well economics.

scholarly journals Modelling of the Long-Term Acid Gas Sequestration and Its Prediction: A Unique Case Study

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4701
Author(s):  
Wiesław Szott ◽  
Piotr Łętkowski ◽  
Andrzej Gołąbek ◽  
Krzysztof Miłek
Keyword(s):  
Geological Structure ◽  
Monitoring Data ◽  
Large Set ◽  
Unique Case ◽  
Acid Gas ◽  
Gas Leakage ◽  
Simulation Results ◽  
Basic Characteristics

A twenty-four-year on-going project of acid gas sequestration in a deep geological structure was subject to detailed modelling based upon a large set of geological, geophysical, and petrophysical data. The model was calibrated against available operational and monitoring data and used to determine basic characteristics of the sequestration process, such as fluid saturations and compositions, their variation in time due to fluid migrations, and the gas transition between free and aqueous phases. The simulation results were analysed with respect to various gas leakage risks. The contribution of various trapping mechanisms to the total sequestrated amount of injected gas was estimated. The observation evidence of no acid gas leakage from the structure was confirmed and explained by the simulation results of the sequestration process. The constructed and calibrated model of the structure was also used to predict the capacity of the analysed structure for increased sequestration by finding the optimum scenario of the risk-free sequestration performance.

Long-term sequestration process in the Borzęcin structure – observation evidence of the injected acid gas migration and possible leakage

2020 ◽  
Author(s):  
Jan Lubaś ◽  
Wiesław Szott ◽  
Piotr Łętkowski ◽  
Andrzej Gołąbek ◽  
Krzysztof Miłek ◽  
...  
Keyword(s):  
Ground Surface ◽  
Gas Migration ◽  
Acid Gas ◽  
Gas Leakage ◽  
Additional Information ◽  
Well Completion ◽  
Future Performance ◽  
Structure Observation ◽  
Basic Characteristics

The monograph presents the results of research carried out under the European SECURe (Subsurface Evaluation of CCS and Unconventional Risks) project in the years 2018-2020. A significant part of the SECURe project comprised evaluation of the effects of the long-term CO₂-H₂S sequestration process in the Borzęcin reservoir structure. This monograph includes all historical operational data determining assumed and implemented parameters of the process and various tests and analyses performed on downhole, as well as surface samples of reservoir fluids, taken from selected wells of the structure. They were aimed at identifying the propagation and intensity of acid gas migration within the structure and potential leakage pathways towards the ground surface. Some of the tests such as analysis of soil gas samples or samples of gas dissolved in brine have never been conducted before, and provided additional information on the safety of geological storage of acid gases within the Borzęcin structure. Corrosion potentials of well tubing and cement were also examined and analysed as they are crucial factors of well completion and leakage prevention. Key components of performed studies and analyses included a simulation model of the Borzęcin structure, constructed from a broad set of geological, geophysical and petrophysical data. The model was calibrated against available operational and measured data, and used to determine basic characteristics of the sequestration process such as: fluid saturations and compositions, their variation in time due to fluid migrations and the transition between various phases. The observation evidence indicating the absence of acid gas leakage from the Borzęcin structure was confirmed and explained by the simulation results of the sequestration process. The constructed and calibrated model of the structure was also used to predict the future performance of the current sequestration project. In addition, the capacity of the Borzęcin structure for increased sequestration was assessed by finding the optimum scenario of the risk-free sequestration performance.

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