Добірка наукової літератури з теми "Annual refrigeration generation"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся зі списками актуальних статей, книг, дисертацій, тез та інших наукових джерел на тему "Annual refrigeration generation".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Статті в журналах з теми "Annual refrigeration generation"
1
Saengsikhiao, Piyanut, and Juntakan Taweekun. "The Data Mining Technique Using RapidMiner Software for New Zeotropic Refrigerant." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 83, no. 1 (June 3, 2021): 70–90. http://dx.doi.org/10.37934/arfmts.83.1.7090.
Повний текст джерелаАнотація:
This research presents the development of environmentally-friendly and energy efficient refrigerant for medium temperature refrigeration systems that new azeotropic refrigerant mixture of hydrofluorocarbons and hydrocarbon that can retrofit in the refrigeration system using R404A. The medium back pressure refrigeration testing standard that follow CAN/ANSI/AHRI540 standard air-conditioning, heating, and refrigeration institute (AHRI) and The properties of refrigerants and refrigeration simulation system that used national institute of standards and technology (NIST) reference fluid thermodynamic and transport properties database (REFPROP) software and NIST vapor compression cycle model accounting for refrigerant thermodynamic and transport properties (CYCLE_D-HX) software. The methodology uses decision tree function in datamining by rapid minor software that first of KDnuggets annual software poll that showed new azeotropic refrigerant mixture had cooling capacity, refrigerant effect, GWP and boiling point were lower than R404A but work and pressure for medium temperature refrigeration system of azeotropic refrigerant mixture were higher than R404A. The artificial intelligence (AI) by data mining technic can predictive environmentally-friendly and energy efficient refrigerant for medium temperature refrigeration. The result of refrigerant mixed by R134A, R32, R125 and R1270 and is consistent with the evolution of fourth-generation refrigerants that contain a mixture of HFCs and HCs which are required to produce a low-GWP, zero-ozone-depletion-potential (ODP), high-capacity, low-operating-pressure, and nontoxic refrigerant.
2
Martínez-Calahorro, Antonio Javier, Gabino Jiménez-Castillo, Catalina Rus-Casas, Pedro Gómez-Vidal, and Francisco José Muñoz-Rodríguez. "Photovoltaic Self-Consumption in Industrial Cooling and Refrigeration." Electronics 9, no. 12 (December 21, 2020): 2204. http://dx.doi.org/10.3390/electronics9122204.
Повний текст джерелаАнотація:
The industrial sector has a great opportunity to reduce its energy costs through distributed generation. In this sense, the potential of photovoltaic self-consumption systems in the industrial cooling and refrigeration sector is shown. Two industries with photovoltaic self-consumption installations are shown and the electricity consumption profile of this type of industry which has a remarkable basal electricity consumption during daytime is analyzed. The matching between consumption and photovoltaic generation profiles is provided through the self-consumption and self-sufficiency curves considering different reporting periods (monthly and annual). Moreover, a new index is presented: self-sufficiency index for sunshine hours, φSS,SH. This index evaluates the performance of the photovoltaic self-consumption system when facing the consumption only during sunshine hours. This index may complement the self-sufficiency index and may improve the analysis of this type of systems in the industrial sector. Self-consumption indices of 90% may be provided. Moreover, self-sufficiency indices for total (24 h) and for sunshine hours of 25% and 50%, respectively, for industry A, and 26% and 45% for industry B have been obtained. During daytime, half the load consumption in this type of industry may be covered by photovoltaics while achieving high levels of use of the photovoltaic energy generated.
3
Stojiljkovic, Mirko, Bratislav Blagojevic, Goran Vuckovic, Marko Ignjatovic, and Dejan Mitrovic. "Optimization of operation of energy supply systems with co-generation and absorption refrigeration." Thermal Science 16, suppl. 2 (2012): 409–22. http://dx.doi.org/10.2298/tsci120503179s.
Повний текст джерелаАнотація:
Co-generation systems, together with absorption refrigeration and thermal storage, can result in substantial benefits from the economic, energy and environmental point of view. Optimization of operation of such systems is important as a component of the entire optimization process in pre-construction phases, but also for short-term energy production planning and system control. This paper proposes an approach for operational optimization of energy supply systems with small or medium scale co-generation, additional boilers and heat pumps, absorption and compression refrigeration, thermal energy storage and interconnection to the electric utility grid. In this case, the objective is to minimize annual costs related to the plant operation. The optimization problem is defined as mixed integer nonlinear and solved combining modern stochastic techniques: genetic algorithms and simulated annealing with linear programming using the object oriented ?ESO-MS? software solution for simulation and optimization of energy supply systems, developed as a part of this research. This approach is applied to optimize a hypothetical plant that might be used to supply a real residential settlement in Nis, Serbia. Results are compared to the ones obtained after transforming the problem to mixed 0-1 linear and applying the branch and bound method.
4
Radchenko, Mykola, Tadeusz Bohdal, Andrii Radchenko, Eugeniy Trushliakov, Veniamin Tkachenko, Oleksii Zielikov, and Felix Tzaran. "Alternative variable refrigerant flow (VRF) air conditioning systems with rational distribution of thermal load." E3S Web of Conferences 323 (2021): 00028. http://dx.doi.org/10.1051/e3sconf/202132300028.
Повний текст джерелаАнотація:
One of the most attractive reserves of enhancing the energetic efficiency of air conditioning systems (ACS) is to provide operation of compressors in closed to nominal modes by choosing the rational design refrigeration capacities and their distribution according to current thermal loading to provide closed to maximum annual refrigeration energy generation. Generally, the overall thermal load band of any ACS comprises the unstable load range, corresponding to ambient air precooling with significant load fluctuations, and a comparatively stable load part for further air conditioning from a threshold temperature to a target value. The stable thermal load range can be covered by operation of conventional compressor in closed to nominal mode, meantime ambient air precooling needs load modulation by applying a variable speed compressor. A proposed ACS enables a wide range of refrigerant flow variation without heat flux drop in air coolers and can be considered as advanced alternative to variable refrigerant flow systems.
5
Akbari Kordlar, Mehri, Florian Heberle, and Dieter Brüggemann. "Evaluation and Optimization of the Annual Performance of a Novel Tri-Generation System Driven by Geothermal Brine in Off-Design Conditions." Applied Sciences 10, no. 18 (September 18, 2020): 6532. http://dx.doi.org/10.3390/app10186532.
Повний текст джерелаАнотація:
The difference in heating or cooling to power ratio between required demands for district networks and the proposed tri-generation system is the most challenging issue of the system configuration and design. In this work, an adjustable, novel tri-generation system driven by geothermal resources is proposed to supply the thermal energies of a specific district network depending on ambient temperature in Germany. The tri-generation system is a combination of a modified absorption refrigeration cycle and a Kalina cycle using NH3-H2O mixture as a working fluid for the whole tri-generation system. A sensitive analysis of off-design conditions is carried out to study the effect of operational parameters on the system performances prior to optimizing its performance. The simulation show that the system is able to cover required heating and cooling demands. The optimization is applied considering the maximum exergy efficiency (scenario 1) and minimum total exergy destruction rate (scenario 2). The optimization results show that the maximum mean exergy efficiency in scenario 1 is achieved as 44.67% at the expense of 14.52% increase in the total exergy destruction rate in scenario 2. The minimum mean total exergy destruction rate in scenario 2 is calculated as 2980 kW at the expense of 8.32% decrease in the exergy efficiency in scenario 1.
6
Sun, Xiaojing, Linlin Liu, Yu Zhuang, Lei Zhang, and Jian Du. "Heat Exchanger Network Synthesis Integrated with Compression–Absorption Cascade Refrigeration System." Processes 8, no. 2 (February 9, 2020): 210. http://dx.doi.org/10.3390/pr8020210.
Повний текст джерелаАнотація:
Compression–absorption cascade refrigeration system (CACRS) is the extension of absorption refrigeration system, which can be utilized to recover excess heat of heat exchanger networks (HENs) and compensate refrigeration demand. In this work, a stage-wise superstructure is presented to integrate the generation and evaporation processes of CACRS within HEN, where the generator is driven by hot process streams, and the evaporation processes provide cooling energy to HEN. Considering that the operating condition of CACRS has significant effect on the coefficient of performance (COP) of CACRS and so do the structure of HEN, CACRS and HEN are considered as a whole system in this study, where the operating condition and performance of CACRS and the structure of HEN are optimized simultaneously. The quantitative relationship between COP and operating variables of CACRS is determined by process simulation and data fitting. To accomplish the optimal design purpose, a mixed integer non-linear programming (MINLP) model is formulated according to the proposed superstructure, with the objective of minimizing total annual cost (TAC). At last, two case studies are presented to demonstrate that desired HEN can be achieved by applying the proposed method, and the results show that the integrated HEN-CACRS system is capable to utilize energy reasonably and reduce the total annualized cost by 38.6% and 37.9% respectively since it could recover waste heat from hot process stream to produce the cooling energy required by the system.
7
Трушляков, Євген Іванович, Андрій Миколайович Радченко, Микола Іванович Радченко, Сергій Анатолійович Кантор та Веніамін Сергійович Ткаченко. "ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ КОНДИЦІЮВАННЯ ЗОВНІШНЬОГО ПОВІТРЯ СИСТЕМИ КОМБІНОВАНОГО ТИПУ". Aerospace technic and technology, № 4 (31 серпня 2019): 9–14. http://dx.doi.org/10.32620/aktt.2019.4.02.
Повний текст джерелаАнотація:
One of the most attractive reserves of enhancing the energetic efficiency of air conditioning systems is to provide the operation of refrigeration compressors in nominal or close to nominal modes by choosing rational design cooling loads (cooling capacities) and their distribution according to a cooling load behaviour within the overall design (installed) cooling load band to match current changeable climatic conditions and provide close to maximum annual cooling capacity generation according to cooling duties. The direction of increasing the efficiency of outdoor air conditioning in combined central-local type systems by rationally distributing the heat load - cooling capacity of the central air conditioner into zones of variable heat load in accordance with current climatic conditions and its relatively stable value, i.e. cooling capacity required for further air cooling at the entrance to the indoor recirculation air conditioning system is justified. By comparing the values of the excessive production of cold and its deficit within every 3 days for a rational design heat load of the air conditioning system (cooling capacity of the installed refrigeration machine), which provides close to maximum annual production of cold, and the corresponding values of the excess and deficit of cooling capacity in accordance with current climatic conditions during July substantiated the feasibility of accumulating the excess of cooling capacity of a central air conditioner at low current loads and its use for covering cooling deficit at elevated heat loads through pre-cooling the outdoor air. It is developed a scheme of a combined central-local air conditioning system, which includes the subsystems for the outdoor air conditioning in a central air conditioner and the local indoor recirculated air conditioning.
8
Sztekler, Karol, Wojciech Kalawa, Wojciech Nowak, Sebastian Stefański, Jarosław Krzywański, Karolina Grabowska, and Łukasz Mika. "Possibility of use adsorption chillers for increase efficiency in conventional power plant." EPJ Web of Conferences 213 (2019): 02082. http://dx.doi.org/10.1051/epjconf/201921302082.
Повний текст джерелаАнотація:
Long-term forecasts indicate that the annual increases in electricity demand by 2030 will be approx. 2 ÷ 3% a year. At present, 40% of the world's electricity is produced using coal-fired power plants. Forecasts indicate that coal will still be the predominant fuel used to produce electricity and thus any actions aimed at increasing the efficiency of electricity production are purposeful. Enormous amounts of waste heat, which is not sufficiently used, are released during the process of electricity production. One of the ways to manage it is to use refrigeration systems based on adsorption chillers which would use waste heat to generate cold that would be employed for air-conditioning or process purposes. In this paper, the cycle of a conventional coal-fired power plant was modelled and then the possibilities of using waste heat for generation of cold as well as the impact of a chiller on the operation of a power unit were analysed using IPSEpro software.
9
Yang, Guang, Yanpeng Fu, Minghui Yan, and Jing Zhang. "Exploring the distribution of energy consumption in a northeast Chinese city based on local climate zone scheme: Shenyang city as a case study." Energy Exploration & Exploitation 38, no. 5 (September 2020): 2079–94. http://dx.doi.org/10.1177/0144598720950465.
Повний текст джерелаАнотація:
The local climate zone (LCZ) scheme is now used to investigate urban heat islands, which provides additional reference for energy consumption simulation. Based on the LCZ scheme, a LCZ mapping of Shenyang, a city in northeast China, was first constructed using the World Urban Database and Access Portal Tools (WUDAPT) Level 0 method. Subsequently, DeST-h was considered to simulate the energy consumption of urban buildings with concentration areas. The results show that with Shenyang being a severely cold area, the annual energy consumption of heating is approximately twice that of refrigeration for an individual building. The total energy consumption of open-distributed single buildings is higher than that of compact-distributed single buildings. Consequently, the unit cumulative energy consumption in compact-distributed buildings is higher than that in openly distributed building areas. The compact high-rise buildings (LCZ 1) have the highest energy consumption, with a unit annual energy consumption of 123,771.150 MW·h, which is equivalent to 41,257 tons of standard coal combustion power generation. Considering the energy consumption of residential buildings, the central high-rise buildings group and the compact centralized middle-rise buildings in the downtown area are high energy consumption areas. For future urban planning, design strategies such as energy-saving transformation and energy planning should be considered. The research results can provide a scientific basis and theoretical support for reducing building energy consumption, alleviating the urban heat island effect, and the development of modern urban planning.
10
Трушляков, Євген Іванович, Андрій Миколайович Радченко, Микола Іванович Радченко, Сергій Георгійович Фордуй, Сергій Анатолійович Кантор та Богдан Сергійович Портной. "МЕТОДОЛОГІЧНІ ПІДХОДИ ДО ВИЗНАЧЕННЯ ХОЛОДОПРОДУКТИВНОСТІ СИСТЕМ КОНДИЦІЮВАННЯ ПОВІТРЯ ЗА ЗМІННИХ КЛІМАТИЧНИХ УМОВ". Aerospace technic and technology, № 7 (31 серпня 2019): 71–75. http://dx.doi.org/10.32620/aktt.2019.7.09.
Повний текст джерелаАнотація:
One of the most attractive reserves for improving the energy efficiency of air conditioning systems is to ensure the operation of refrigeration compressors in nominal or close to nominal modes by selecting a rational design heat load and distributing it within its design value according to the behavior of the current heat load under variable current climatic conditions to provide the maximum or close to maximum annual cooling capacity generation according to cooling duties of air conditioning. In the general case, the overall range of current thermal loads of any air conditioning system includes a range of unstable loads associated with the precooling of ambient air with significant fluctuations in cooling capacity according with current climatic conditions, and a relatively stable range of cooling capacity consumed to further reduce air temperature from a certain threshold temperature to the final outlet temperature. It is quite obvious that a stable range of heat load can be ensured within operating a conventional compressor in a mode close to the nominal mode while precooling the ambient air with significant fluctuations in heat load requires regulation of the cooling capacity through the use of a variable speed compressor. Thus, in response of the behavior of the change in current heat loads, any air conditioning system, whether the central air-conditioning system with its heat procession in a central air conditioner, or a combination thereof with a local recirculation system of indoor air, essentially consists of two subsystems: pre-cooling the ambient air and then cooling it to the set point temperature. The proposed method of distribution of design heat load depending on the behavior of the current heat load is useful for the rational design of central air conditioning systems and their combined versions with the local air conditioning system.
Дисертації з теми "Annual refrigeration generation"
1
Трушляков, Є. І., А. М. Радченко, Б. С. Портной, С. Г. Фордуй, E. I. Trushliakov, A. M. Radchenko, B. S. Portnoi та S. G. Forduy. "Методи визначення теплового навантаження систем кондиціювання повітря з урахуванням поточних кліматичних умов". Thesis, 2019. http://eir.nuos.edu.ua/xmlui/handle/123456789/4332.
Повний текст джерелаАнотація:
Методи визначення теплового навантаження систем кондиціювання повітря з урахуванням поточних кліматичних умов = Methods to determine the heat load of air conditioning systems with account of current climatic conditions / Є. І. Трушляков, А. М. Радченко, Б. С. Портной, С. Г. Фордуй // Матеріали X міжнар. наук.-техн. конф. "Інновації в суднобудуванні та океанотехніці". В 2 т. – Миколаїв : НУК, 2019. – Т. 1. – С. 493–497.Анотація. Одним з найбільш привабливих резервів підвищення енергетичної ефективності систем кондиціювання повітря є забезпечення роботи холодильних компресорів в номінальному або близькому до номінального режимах шляхом вибору раціонального проектного теплового навантаження та його розподілу в межах його проектної величини відповідно до характеру поточного теплового навантаження за змінних поточних кліматичних умов з метою максимального або близького до нього річного виробництва холоду відповідно до його витрат на кондиціювання повітря. В загальному випадку весь діапазон поточних теплових навантажень будь-якої системи кондиціювання повітря включає діапазон нестабільних навантажень, пов’язаних з попереднім охолодженням зовнішнього повітря зі значними коливаннями витрат холодопродуктивності відповідно до поточних кліматичних умов, і порівняно стабільну частку холодильної потужності, що витрачається на подальше зниження температури повітря від певної порогової температури до кінцевої температури на виході. Цілком очевидно, що стабільний діапазон теплового навантаження може бути забезпечений при роботі звичайного компресора в режимі, близькому до номінального режимі, тоді як попереднє охолодження зовнішнього повітря зі значними коливаннями теплового навантаження потребує регулювання холодопродуктивності шляхом застосування компресора з регульованою швидкістю. Таким чином, за характером зміни поточних теплових навантажень будь-яка система кондиціювання повітря, чи то центральна система кондиціювання повітря з його тепловологісною обробкою в центральному кондиціонері, чи то її комбінація з місцевою рециркуляційною системою кондиціювання повітря в приміщеннях, по суті, складається з двох підсистем: попереднього охолодження зовнішнього повітря і його подальшого охолодження до встановленої кінцевої температури. Запропонований метод розподілу проектного теплового навантаження в залежності від характеру поточних теплових навантажень є корисним для раціонального проектування систем центрального кондиціювання повітря та їх комбінованих версій з місцевою системою кондиціювання повітря.
Abstract. One of the most attractive reserves for improving the energy efficiency of air conditioning systems is to ensure the operation of refrigeration compressors in nominal or close to nominal modes by selecting a rational design heat load and distributing it within its design value according to the behavior of the current heat load under variable current climatic conditions to provide the maximum or close to maximum annual cooling capacity generation accord-ing to cooling duties of air conditioning. In the general case, the overall range of current thermal loads of any air conditioning system includes a range of unstable loads associated with the precooling of ambient air with significant fluctuations in cooling capacity according with current climatic conditions, and a relatively stable range of cooling capacity consumed to further reduce air temperature from a certain threshold temperature to the final outlet tem-perature. It is quite obvious that a stable range of heat load can be ensured within operating a conventional com-pressor in a mode close to the nominal mode, while precooling the ambient air with significant fluctuations in heat load requires regulation of the cooling capacity through the use of a variable speed compressor. Thus, in response of the behavior of the change in current heat loads, any air conditioning system, whether the central air-conditioning system with its heat procession in a central air conditioner, or a combination thereof with a local recirculation sys-tem of indoor air, essentially consists of two subsystems: pre-cooling the ambient air and then cooling it to the set point temperature. The proposed method of distribution of design heat load depending on the behaviour of current heat load is useful for the rational design of central air conditioning systems and their combined versions with the local air conditioning system.
Аннотация. Одним из самых привлекательных резервов повышения энергетической эффективности систем кондиционирования воздуха является обеспечение работы холодильных компрессоров в номинальном или близком к номинальному режимах путем выбора рационального проектной тепловой нагрузки и ее распределения в пределах ее проектной величины в соответствии с характером текущей тепловой нагрузки в соответствии с меняющимися текущими климатическими условиями с целью максимального или близкого к нему годового производства холода в соответствии с его расходованием на кондиционирование воздуха. В общем случае весь диапазон текущих тепловых нагрузок любой системы кондиционирования воздуха включает диапазон нестабильных нагрузок, связанных с предварительным охлаждением наружного воздуха со значительными колебаниями затрат холодопроизводительности в соответствии с текущими климатическими условиями, и сравнительно стабильную долю холодопроизводительности, расходуемой на снижение температуры воздуха от определенной пороговой температуры до конечной температуры на выходе. Совершенно очевидно, что стабильный диапазон тепловой нагрузки может быть обеспечен при работе обычного компрессора в режиме, близком к номинальному, тогда как предварительное охлаждение наружного воздуха со значительными колебаниями тепловой нагрузки требует регулирования холодопроизводительности путем применения компрессора с регулируемой скоростью. Таким образом, по характеру изменения текущих тепловых нагрузок любая система кондиционирования воздуха, то ли центральная система кондиционирования воздуха с его тепловлажностной обработкой в центральном кондиционере, то ли ее комбинация с местной рециркуляционной системой кондиционирования воздуха в помещениях, по сути, состоит из двух подсистем: предварительного охлаждения наружного воздуха и его дальнейшего охлаждения до установленной конечной температуры. Предложенный метод распределения проектного тепловой нагрузки в зависимости от характера текущих тепловых нагрузок весьма полезный для рационального проектирования систем центрального кондиционирования воздуха и их комбинированных версий с местной системой кондиционирования воздуха.
2
Трушляков, Є. І., А. М. Радченко, В. С. Ткаченко, Б. С. Портной, С. Г. Фордуй, С. А. Кантор, E. I. Trushliakov та ін. "Ступеневий принцип розподілу теплового навантаження в системі кондиціювання повітря". Thesis, 2019. http://eir.nuos.edu.ua/xmlui/handle/123456789/4333.
Повний текст джерелаАнотація:
Ступеневий принцип розподілу теплового навантаження в системі кондиціювання повітря = The stage principle of distribution of thermal load in air conditioning systems / Є. І. Трушляков, А. М. Радченко, В. С. Ткаченко, Б. С. Портной, С. Г. Фордуй, С. А. Кантор // Матеріали X міжнар. наук.-техн. конф. "Інновації в суднобудуванні та океанотехніці". В 2 т. – Миколаїв : НУК, 2019. – Т. 1. – С. 504–508.Анотація. Підтримання роботи холодильних компресорів в номінальному або близькому до нього режимах шляхом вибору раціонального проектного теплового навантаження та його розподілу за характером зміни поточного теплового навантаження відповідно до поточних кліматичних умов є одним з перспективних резервів підвищення енергетичної ефективності систем кондиціювання повітря, реалізація якого забезпечує досягнення максимального або близького до нього річного виробництва холоду відповідно до його витрат на кондиціювання повітря. В загальному випадку весь діапазон поточних теплових навантажень будь-якої системи кондиціювання повітря включає діапазон нестабільних навантажень, обумовлених попереднім охолодженням зовнішнього повітря зі значними коливаннями витрат холодопродуктивності відповідно до поточних кліматичних умов, і діапазон порівняно стабільної холодильної потужності, що витрачається на подальше зниження температури повітря від певної порогової температури до кінцевої температури на виході. Якщо діапазон стабільного теплового навантаження може бути забезпечений при роботі звичайного компресора в режимі, близькому до номінального, то попереднє охолодження зовнішнього повітря зі значними коливаннями теплового навантаження потребує регулювання холодопродуктивності шляхом застосування компресора з регульованою швидкістю або ж використання надлишку холоду, закумульованого при знижених теплових навантаженнях. Такий ступеневий принцип охолодження забезпечує узгодження роботи холодильних машин з характером зміни поточних теплових навантажень будь-якої системи кондиціювання повітря, чи то центральної системи кондиціювання повітря з його тепловологісною обробкою в центральному кондиціонері, чи то її комбінації з місцевою рециркуляційною системою кондиціювання повітря в приміщеннях, по суті, як комбінації підсистем – попереднього охолодження зовнішнього повітря з регулюванням холодопродуктивності та подальшого охолодження повітря до встановленої кінцевої температури в умовах відносно стабільного теплового навантаження.
Abstract. Maintaining the operation of refrigeration compressors in nominal or close modes by selecting a rational design thermal load and distributing it in response to the behavior of the current thermal load according to the current climatic conditions is one of the promising reserves for improving the energy efficiency of air conditioning systems, which implementation ensures maximum or close to it in the annual cooling production according to air conditioning duties. In general case, the total range of current thermal loads of any air-conditioning system includes a range of unstable loads caused by precooling of ambient air with significant fluctuations in the cooling capacity according to current climatic conditions, and a range of relatively stable cooling capacity expended for further lowering the air temperature from a certain threshold temperature to the final outlet temperature. If a range of stable thermal load can be provided within operating a conventional compressor in a mode close to nominal, then precooling the ambient air with significant fluctuations in thermal load requires adjusting the cooling capacity by using a variable speed compressor or using excess of heat accumulated at reduced load. Such a stage principle of cooling ensures the operation of refrigerating machines matching the behavior of current thermal loads of any air-conditioning system, whether the central air conditioning system with ambient air procession in the central air conditioner, or its combination with the local indoors recirculation air conditioning systems in the air-conditioning system. in essence, as combinations of subsystems – precooling of ambient air with regulation of cooling capacity and subsequent cooling air to the mouth of the set point temperature under relatively stable thermal load.
Аннотация. Поддержание работы холодильных компрессоров в номинальном или близком к нему режимах путем выбора рациональной проектной тепловой нагрузки и ее распределения согласно характеру изменения текущей тепловой нагрузки в соответствии с текущими климатическими условиями является одним из перспективных резервов повышения энергетической эффективности систем кондиционирования воздуха, реализация которого обеспечивает достижение максимального или близкого к нему годового производства холода в соответствии с его расходованием на кондиционирование воздуха. В общем случае весь диапазон текущих тепловых нагрузок любой системы кондиционирования воздуха включает диапазон нестабильных нагрузок, обусловленных предварительным охлаждением наружного воздуха со значительными колебаниями затрат холодопроизводительности в соответствии с текущими климатическими условиями, и диапазон сравнительно стабильной холодопроизводительности, расходуемой на дальнейшее понижение температуры воздуха от некоторой пороговой температуры до конечной температуры на выходе. Если диапазон стабильной тепловой нагрузки может быть покрыт при работе обычного компрессора в режиме, близком к номинальному, то предварительное охлаждение наружного воздуха со значительными колебаниями тепловой нагрузки требует регулирования холодопроизводительности путем применения компрессора с регулируемой скоростью или использования избытка холода, аккумулированного при пониженных тепловых нагрузках. Такой ступенчатый принцип охлаждения обеспечивает согласование работы холодильных машин с характером изменения текущих тепловых нагрузок любой системы кондиционирования воздуха, то ли центральной системы кондиционирования воздуха с его тепловлажностной обработкой в центральном кондиционере, то ли ее комбинации с местной циркуляционной системой кондиционирования воздуха в помещениях, по сути, как комбинации подсистем–предварительного охлаждения наружного воздуха с регулированием холодопроизводительности и последующего охлаждения воздуха до конечной температуры в условиях относительно стабильной тепловой нагрузки.
Тези доповідей конференцій з теми "Annual refrigeration generation"
1
Grzebielec, Andrzej, Rafał Laskowski, and Adam Ruciński. "Influence of Outside Temperature on the Operation of the Adsorption Chiller." In Environmental Engineering. VGTU Technika, 2017. http://dx.doi.org/10.3846/enviro.2017.255.
Повний текст джерелаАнотація:
Adsorption refrigeration systems are characterized by a lower coefficient of performance than the compressor type device or even absorption, but can utilize waste heat at lower temperature. The aim of the study was to determine which external parameter has the greatest impact on the efficiency of the adsorption device. As a result of experimental studies there was found that this is not the temperature of the feed but particularly the temperature of external air. For this reason, it is recommended that the adsorption device should cooperate with evaporative spray coolers, instead of with popular dry coolers. This solution will increase annual efficiency of adsorption unit approx. by 25% and significantly reduce the costs of cold generation.
2
Yoshida, Hideo, Yuhei Iwamoto, Akio Ueda, and Motohiro Saito. "Performance Evaluation of the Micro Cogeneration System Composed of Microturbine, Solid Oxide Fuel Cell, and H2O/LIBR Absorption Refrigerator." In ASME 2005 Power Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pwr2005-50357.
Повний текст джерелаАнотація:
A micro cogeneration system composed of a microturbine (MGT), a solid oxide fuel cell (SOFC) and an absorption refrigerator is analyzed thermodynamically. The performance analysis is conducted on the basis of the macroscopic mass and energy balances with additional empirical correlations and operating data. First, the basic characteristics of the power generation (MGT+SOFC) section and the absorption refrigerator section are clarified. Second, under the conditions of the cell temperature of 900 °C and the turbine inlet temperature of 900 °C, the optimum design points are determined. Furthermore, the energy saving obtained by the present system through the annual operation is also evaluated in the light of the measured data in Japan. As a result, the annual fuel consumptions are reduced by 32%, 36% and 42%, for apartments, offices and hotels, respectively.
3
Kho, Seonghee, Jayoung Ki, and Myoungcheol Kang. "Feasibility Assessment for ORC Generation System Development Using Low Temperature Geothermal Water." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-26870.
Повний текст джерелаАнотація:
Since around 70°C of geothermal water exists in Seokmo-do of Republic of Korea, this study is to assess the feasibility of electricity generation by utilizing ORC system, and the pertinent economic impact. It is generally believed that economic feasibility can be secured only when the source of geothermal water is above 100°C in order to generate electricity by operating ORC system. However, there was an exceptional case that ORC system was commercialized by Pratt-Whitney for around 70 °C of geothermal water in the hot springs of Chena, Alaska. The annual average temperature in the hot springs of Chena, Alaska is approximately 1°C whereas that of Seokmo-do is around 11°C, which makes 10°C of annual average temperature difference in operational environment between the two. Thus, the 2 phases of absorption refrigerating machine is considered for the ORC generation system. With establishing ORC system in consideration of operational environment, the feasibility of the development of ORC system in Seokmo-do is assessed by performance analysis and economic feasibility. As a result of the assessment, it is identified that the economic feasibility can be secured if the price of electricity is over $0.42/kWh same as that of photovoltaic generation as an incentive of the RPS program granted by the Korean government.
4
Ortiz-Vidal, Luis Enrique, Oscar M. H. Rodriguez, and Njuki Mureithi. "An Exploratory Experimental Technique to Predict Two-Phase Flow Pattern From Vibration Response." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-98115.
Повний текст джерелаАнотація:
Gas-liquid pipe flow is common in nuclear, gas & oil, refrigeration and power generation industries, where gas-liquid mixtures are transported in piping systems. The mixtures flows in different flow patterns, such as bubbly, slug and annular, generating dynamic fluid forces which may induce structural vibration. In many industrial cases, Flow-Induced Vibrations (FIV) are an intrinsic part of the piping operation and does not present risks that may lead to structural component failures. In this sense, the information available on this topic is quite scanty. In this paper, we present an in-depth discussion about the phenomenology of the FIV due to two-phase pipe flow. A set of 32 two-phase horizontal flow conditions was collected, including bubbly, slug and dispersed flow-patterns. The homogeneous mixture velocity J was in the range of 0.5 to 25 m/s, with homogeneous void fractions of β = 10%, 25%, 50%, 75% and 95%. Signals of acceleration were acquired to correlate pipe vibration and two-phase flow parameters. Results show higher acceleration levels in slug and dispersed than in bubbly flow. We find that the acceleration frequency response contains useful information of the flow. Comparisons with single-phase flow are also presented. Finally, an exploratory experimental technique to predict two-phase flow pattern from vibration response based on the combination resonance caused by both single and two-phase flow is proposed. The results indicate that the proposed-technique is acceptable to recognize intermittent flow patterns in two-phase flow.
5
Pacio, Julio C., and Carlos A. Dorao. "Modelling Two-Phase Heat Exchanger Performance in the Annular-Mist Flow Regime Considering Entrainment and Deposition Phenomena." In ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-10013.
Повний текст джерелаАнотація:
Two-phase flow heat exchangers are main components of large cryogenics, power generation, refrigeration and liquefaction of natural gas plants, both in terms of capital cost and technical challenges. A major challenge in their design is the prediction of local heat transfer coefficients and pressure gradients for the evaporating or condensing fluids. Traditional heat exchanger models are based on one single correlation for predicting the heat transfer in the entire saturated boiling regime, disregarding the flow structure. However, the structure of the flow dictates how the different physical processes (nucleate boiling, convective heat transfer to the liquid and vapour phase, thin film evaporation) interact and contribute to the total heat transfer. In particular, a relevant flow-regime transition for the sizing of heat exchangers is the occurrence of dryout during the evaporation process in the annular-mist flow regime. The objective of this work is to present a three-field model for describing the annular-mist flow considering a liquid film, liquid droplets and a vapor phase, and predicting the occurrence of dryout. The flow structure is affected by the entrainment, deposition and evaporation. These processes are studied on the base of semi-empirical models. The final mathematical model is implemented into an in-house solver. The model is validated with uniform heat flux data available in the open literature. While the model performs well in the case of water flows (within 10% error), the uncertainties are larger for other fluids, probably due to the applicability range of the empirical models. Finally, two numerical examples considering the sensitivity of the input parameters and axial power distribution are studied.
6
Cao, Jiming, and Richard N. Christensen. "Modeling an Integral Dual Solar/Gas Fired Generator for a Water-Lithium Bromide Absorption Chiller." In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0823.
Повний текст джерелаАнотація:
Abstract This paper presents a design process for a dual solar/gas fired generator. A generator fired by solar energy and/or natural gas for a water-lithium bromide absorption chiller of 25 refrigeration tons (RT) was modeled. The natural gas is considered as the backup heat when the solar energy is unavailable or insufficient. The flue gas and the water-lithium bromide solution are in co-current flow, while the solar fluid and the water-lithium bromide solution are in counter-current flow. Fifty fluted tubes were installed vertically between two concentric cylindrical tubes. A solid ceramic insert was used to enhance heat transfer on the gas side that is considered as having the dominant heat transfer resistance. The burner is installed inside the smaller cylindrical tube. The solar fluid from the solar collector enters the generator through the fluted tubes while the water-lithium bromide mixture flows in the annular channel around the fluted tubes as a subcooled liquid. The generator is divided into two regions according to the heat transfer mechanism: subcooled liquid region and desorption region. In this model, a simultaneous solar and gas fired desorption process was investigated. The amount of makeup heat needed from natural gas was determined as a function of the solar fluid flow rate. Local temperature profiles were predicted by the model.
7
Zhang, TieJun, Juan Catano, Evelyn N. Wang, and Michael K. Jensen. "Pre- and Post-Critical Heat Flux Analyses in a Saturated Refrigerant Flow Boiling System." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-85795.
Повний текст джерелаАнотація:
Vapor compression refrigeration (VCR) cooling has been identified as a promising solution to ensure the low-temperature sustainable operation of photonics, avionics and electronics in extreme hot weather. With the inherent benefits of saturated flow boiling in a direct VCR cooling cycle, uniform low surface temperature and low solid/liquid thermal resistances can be achieved. However, flow boiling heat transfer performance is limited by the relatively low critical heat flux (CHF) condition because the evaporator inlet flow is already a liquid/vapor mixture. Moreover, for the aforementioned applications, the dissipated heat loads are usually subject to large and transient changes, which could easily cause the evaporating flow to exceed the CHF point. Therefore, it is important to characterize boiling heat transfer in transient VCR evaporators under both pre-CHF and post-CHF conditions. Comprehensive experimental data are reported in this paper to describe the complete forced convection boiling hysteresis at the evaporator exit. Several well-known boiling heat transfer correlations and flow pattern criteria are used to help understand the physics of the hysteresis. An empirical model is developed to reveal the unstable nature of transition flow boiling dynamics. A probability distribution function model is further proposed to predict the droplet size in mist flow and vapor core of annular flow. This study provides more design and operating guidelines for the application of saturated flow boiling systems in renewable power generation and electronics/photonics/avionics cooling industries.
8
Li, Xianchang, Ting Wang, and Benjanmin Day. "Improving the Performance of a Thermal Compressor in a Steam Evaporator via CFD Analysis." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-12651.
Повний текст джерелаАнотація:
Ejectors have been widely used in many applications such as water desalination, steam turbine power generation, refrigeration systems, and chemical plants. The advantage of an ejector system lies in its extremely reliable and stable operation due to the complete absence of moving parts. However, the performance depends on a number of factors, among which the flow channel configuration/arrangement is very critical. A comprehensive study mainly focusing on the sensitivity of performance on the geometric arrangement was conducted in this paper to improve an existing thermal compressor performance in a steam evaporator. The performance is measured by the suction (secondary) flow rate of the primary steam jet from a low-pressure vapor plenum. Numerical simulation is employed to investigate the thermal-flow behavior. It is observed that any downstream resistance will seriously impede the suction flow rate. In addition, the suction rate is found to be sensitive to the location of the jet exit, and there is an optimum location where the jet should be issued. A well-contoured diffuser can increase the suction rate significantly. However, the size of suction opening to the plenum is less important, and a contoured annular passage to guide the entrained flow shows little effect on the overall performance. Based on the numerical results the steam suction rate of the best case in the confinement of the current study is approximately 430% the jet flow rate, while some cases with mediocre design can only produce an entrainment of 24% the jet flow.
9
Sole, Joshua D., Bradley J. Shelofsky, Robert P. Scaringe, and Gregory S. Cole. "Cavitation-Enhanced Microchannel Heat Exchanger Demonstration and Heat Transfer Correlation Development Using R-134a." In ASME 2012 Heat Transfer Summer Conference collocated with the ASME 2012 Fluids Engineering Division Summer Meeting and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ht2012-58109.
Повний текст джерелаАнотація:
Electronics of all types, particularly those in the military aviation arena, are decreasing in size while at the same time increasing in power. As a result, newer high-heat-flux electronic components are exceeding the cooling capabilities of conventional single-phase military aviation coldplates and coolants. It is for this reason that we have been investigating new methods to cool the next generation of high-heat-flux military aviation electronics. In this work, a novel method of inducing two-phase conditions within a microchannel heat exchanger has been developed and demonstrated. Micro-orifices placed upstream of each microchannel in a microchannel heat exchanger not only cause an improvement in flow distribution, but can also induce cavitation in the incoming subcooled refrigerant and result in favorable two-phase flow regimes for enhanced heat transfer. In this study, R-134a is used as the coolant in the cavitation enhanced microchannel heat exchanger (CEMC-HX) which has been integrated into a vapor compression refrigeration system. Multiple micro-orifice geometries combined with a fixed microchannel geometry (nominally 250 μm × 250 μm) were investigated over a range of applied base heat fluxes (10–100 W/cm2) and mass fluxes (500–1000 kg/m2-s). Two-phase heat transfer coefficients exceeding 100,000 W/m2-K at refrigerant qualities of less than 5% have been demonstrated due to the achievement of preferential, cavitation-induced, flow regimes such as annular flow. To the author’s knowledge, this is the highest heat transfer coefficient ever reported in the literature for R-134a. Additionally, a four term two-phase heat transfer correlation was developed that achieved a mean absolute error (MAE) of 25.5%.
10
Campbell Ramírez, Héctor Enrique, René Delgado Rendón, Alejandro A. Lambert Arista, and Margarita Gil Samaniego Ramos. "Solar Energy in the Housing: Case — Mexicali, Baja California, Mexico." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64916.
Повний текст джерелаАнотація:
A study was designed and implemented to simulate and validate experimentally the thermal performance and energy of two houses equipped for efficient use of energy in Mexicali, Baja California, Mexico. The objectives were the simulation and the assessment of energetic, economic, social and environmental impacts of the use of high efficiency air conditioning, high efficiency refrigerators, Solar Water Heater (SWH) and photovoltaic (PV) modules. The simulations carried out were validated by field measurements during years 2011 and 2012. For PV systems, we estimated generation of 1837 kWh/yr. and in the annual monitoring values were obtained 1855 kWh/yr. For SWH, the investment is recovered within a reasonable time (6 years) by saving conventional energy. Electricity consumption per unit area of building for winter and summer was 0.23 and 0.46 kWh/ft2, respectively. The field data of average power for the AC is consistent with the SEER 13 being of 1.0 kW, and for the refrigerator, average power was 128 W. For the 2-story house (1033 sq. ft.), simulation predicted an annual consumption of 4559 kWh and measured value was 4197, PV system contributed 55% of consumption. In regard to the estimated electric bill was for $233 USD, and the reported value was $207 USD. The PV cells contributed with 60%, and the electric utility invoice was $78 USD. In these prototype homes is significantly diminishing electricity consumption in contrast to habitual housing. When energy efficiency is achieved as a first goal, the contribution of renewable energy becomes significant. However, for the PV systems, there is much to do, as combining lower investment with funding polices, because, when energy use is reduced, by energy efficiency and saving programs, customers have a subsidized electricity rate. We strongly recommend focus the subsidy for the users and not to the electricity rates. The way to use energy and habits of user, impacts significantly saving actions and energy efficient and the development of renewable energy. It is not easy to compare houses with different family behaviors. We recommend carry out energy education programs, to induce the market for energy saving and renewable. The monitoring allowed a better assessment of current performance of photovoltaic modulus and inverters, and the effects of temperature; radiation changes due to shade and clouds; dust on surfaces, and of the quality and stability of the supply lines (voltage variations), over their behavior and efficiency. Finally, field experiences will help to develop non-invasive systems, using telemetry of data and control commands, which must be combined with the design of house facilities in such a way forward to smart systems.