Articoli di riviste: "Heat recovery"

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Ion, Ion V., Antoaneta Ene e Gabriel Mocanu. "Boiler blowdown recovery". Annals of the ”Dunarea de Jos” University of Galati Fascicle II Mathematics Physics Theoretical Mechanics 44, n. 2 (29 dicembre 2021): 98–102. http://dx.doi.org/10.35219/ann-ugal-math-phys-mec.2021.2.03.

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One way to reduce the heat loss of the steam boiler is to reduce the blowdown rate and recover the heat from the purged water. Purging the boiler, although necessary, represents a loss of treated water and a loss of heat because the purged water is water brought to saturation. Blowdown recovery must be done according to the available users/consumers. The paper analyses the recovery of blowdown of a steam boiler of 420 t/h capacity by using a flash separator and a makeup water preheater. The flash steam is used for the feed water deaeration. The heat recovered from the blowdown can reach 97%, and the recovered water can reach 43%.

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SAARI, JUSSI, JUHA KAIKKO, EKATERINA SERMYAGINA, MARCELO HAMAGUCHI, MARCELO CARDOSO, ESA VAKKILAINEN e MARKUS HAIDER. "Recovery boiler back-end heat recovery". March 2023 22, n. 3 (1 aprile 2023): 174–83. http://dx.doi.org/10.32964/tj22.3.174.

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Sustainability and efficient use of resources are becoming increasingly important aspects in the operation of all industries. Recently, some biomass-fired boilers have been equipped with increasingly complex condensing back-end heat recovery solutions, sometimes also using heat pumps to upgrade the low-grade heat. In kraft recovery boilers, however, scrubbers are still mainly for gas cleaning, with only simple heat recovery solutions. In this paper, we use process simulation software to study the potential to improve the power generation and energy efficiency by applying condensing back-end heat recovery on a recovery boiler. Different configurations are considered, including heat pumps. Potential streams to serve as heat sinks are considered and evaluated. Lowering the recovery boiler flue gas temperature to approximately 65°C significantly decreases the flue gas losses. The heat can be recovered as hot water, which is used to partially replace low-pressure (LP) steam, making more steam available for the condensing steam turbine portion for increased power generation. The results indicate that in a simple condensing plant, some 1%–4% additional electricity could be generated. In a Nordic mill that provides district heating, even more additional electricity generation, up to 6%, could be achieved. Provided the availability of sufficient low-temperature heat sinks to use the recovered heat, as well as sufficient condensing turbine swallowing capacity to utilize the LP steam, the use of scrubbing and possibly upgrading the heat using heat pumps appears potentially useful.

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Vannoni, Alberto, Alessandro Sorce, Sven Bosser e Torsten Buddenberg. "Heat recovery from Combined Cycle Power Plants for Heat Pumps". E3S Web of Conferences 113 (2019): 01011. http://dx.doi.org/10.1051/e3sconf/201911301011.

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Fossil fuel power plants, as combined cycle plants (CCGT), will increasingly have to shift their role from providing base-load power to providing fluctuating back-up power to control and stabilize the grid, but they also have to be able to run at the highest possible efficiency. Combined Heat and Power generation could be a smart solution to overcome the flexibility required to a modern power plant, this work investigates different layout possibilities allowing to increase the overall efficiency through the heat recover from the hot flue gasses after the heat recovery steam generator (HRSG) of a CCGT. The flue gas (FG) cooling aims to recover not only the sensible heat but also the latent heat by condensing the water content. One possible solution couples a heat pump to the flue gas condenser in order to increase the temperature at which the recovered heat is supplied, moreover the evaluated layout has to comply with the requirement of a minimum temperature before entering the stack.

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Vivek, P., e P. Vijaya kumar. "Heat Recovery Steam Generator by Using Cogeneration". International Journal of Engineering Research 3, n. 8 (1 agosto 2014): 512–16. http://dx.doi.org/10.17950/ijer/v3s8/808.

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Kim, Yurim, Jonghun Lim, Jae Yun Shim, Seokil Hong, Heedong Lee e Hyungtae Cho. "Optimization of Heat Exchanger Network via Pinch Analysis in Heat Pump-Assisted Textile Industry Wastewater Heat Recovery System". Energies 15, n. 9 (23 aprile 2022): 3090. http://dx.doi.org/10.3390/en15093090.

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Reactive dyeing is primarily used in the textile industry to achieve a high level of productivity for high-quality products. This method requires heating a large amount of freshwater for dyeing and cooling for the biological treatment of discharged wastewater. If the heat of the wastewater discharged from the textile industry is recovered, energy used for heating freshwater and cooling wastewater can be significantly reduced. However, the energy efficiency of this industry remains low, owing to the limited use of waste heat. Hence, this study suggested a cost-optimal heat exchanger network (HEN) in a heat pump-assisted textile industry wastewater heat recovery system with maximizing energy efficiency simultaneously. A novel two-step approach was suggested to develop the optimal HEN in heat pump-assisted textile industry wastewater heat recovery system. In the first step, the system was designed to integrate the heat exchanger and heat pump to recover waste heat effectively. In the second step, the HEN in the newly developed system was retrofitted using super-targeted pinch analysis to minimize cost and maximize energy efficiency simultaneously. As a result, the proposed wastewater heat recovery system reduced the total annualized cost by up to 43.07% as compared to the conventional textile industry lacking a wastewater heat recovery system. These findings may facilitate economic and environmental improvements in the textile industry.

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Losnegard, Thomas, Martin Andersen, Matt Spencer e Jostein Hallén. "Effects of Active Versus Passive Recovery in Sprint Cross-Country Skiing". International Journal of Sports Physiology and Performance 10, n. 5 (luglio 2015): 630–35. http://dx.doi.org/10.1123/ijspp.2014-0218.

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Purpose:To investigate the effects of an active and a passive recovery protocol on physiological responses and performance between 2 heats in sprint cross-country skiing.Methods:Ten elite male skiers (22 ± 3 y, 184 ± 4 cm, 79 ± 7 kg) undertook 2 experimental test sessions that both consisted of 2 heats with 25 min between start of the first and second heats. The heats were conducted as an 800-m time trial (6°, >3.5 m/s, ~205 s) and included measurements of oxygen uptake (VO2) and accumulated oxygen deficit. The active recovery trial involved 2 min standing/walking, 16 min jogging (58% ± 5% of VO2peak), and 3 min standing/walking. The passive recovery trial involved 15 min sitting, 3 min walk/jog (~ 30% of VO2peak), and 3 min standing/walking. Blood lactate concentration and heart rate were monitored throughout the recovery periods.Results:The increased 800-m time between heat 1 and heat 2 was trivial after active recovery (effect size [ES] = 0.1, P = .64) and small after passive recovery (ES = 0.4, P = .14). The 1.2% ± 2.1% (mean ± 90% CL) difference between protocols was not significant (ES = 0.3, P = .3). In heat 2, peak and average VO2 was increased after the active recovery protocol.Conclusions:Neither passive recovery nor running at ~58% of VO2peak between 2 heats changed performance significantly.

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Łokietek, Tomasz, Wojciech Tuchowski, Dorota Leciej-Pirczewska e Anna Głowacka. "Heat Recovery from a Wastewater Treatment Process—Case Study". Energies 16, n. 1 (21 dicembre 2022): 44. http://dx.doi.org/10.3390/en16010044.

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This article presents the potential of heat recovery from wastewater with an example of a wastewater treatment plant (WWTP) in Mokrawica, which is located in the West Pomeranian region of Poland. A thorough literature review discusses the relevance of the topic and shows examples of heat recovery conducted with heat pumps. Raw and treated wastewater are mostly used as heat sources, with the latter achieving higher thermal capacities. Heat recovery from a biological treatment process is rarely implemented and requires more detailed studies on this subject. The proposed methodology for estimating possible heat recovered from wastewater, requiring heating and cooling capacities, as well as the coefficient of performance (COP) of a heat pump, is based on only three parameters: wastewater volumetric flow, wastewater temperature, and the required temperature for heating or air-conditioning. The heat recovery potential was determined for different parts of WWTP processes, i.e., the sand box, aeration chamber, secondary sedimentation tank, and treated sewage disposal. The average values of 309–451 kW and a minimum of 58–68 kW in winter were determined. The results also indicate that, depending on the location of the heat recovery, it is possible to obtain from wastewater between 57.9 kW and 93.8 kW of heat or transfer to wastewater from 185.9 to 228.2 kW. To improve biological treatment processes in the winter season, wastewater should be preheated with a minimum of 349–356 kW that can be recovered from the treated wastewater. The heat transferred to the wastewater from the air-conditioning system amounts to 138–141 kW. By comparing the required cooling and heating capacities with the available resources, it is possible to fully recover or transfer the heat for central heating, hot water, and air conditioning of the building. Partial preheating of wastewater during the treatment process requires further analysis.

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Soundararajan, Srinath, e Mahalingam Selvaraj. "Investigations of protracted finned double pipe heat exchanger system for waste heat recovery from diesel engine exhaust". Thermal Science, n. 00 (2023): 143. http://dx.doi.org/10.2298/tsci230212143s.

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The need for energy and material savings, as well as environmental concerns, have helped to increase the demand for high-efficiency heat exchangers in the modern era. In practice, a heat exchanger or the direct ejection of the hot working fluid is used to recover the waste heat from a heat engine or thermal power plant into the environment. Waste heat of a heat engine or power plant is recovered to the environment via a heat exchanger or by direct ejection from the hot working fluid. In many situations, waste heat recovery removes or greatly reduces the necessity for additional fuel energy input to achieve this goal. The double pipe heat exchanger equipment is taken in this research, heat from engine exhaust recovers due to its superior qualities. The design characteristics of the heat pipe will be changed in order to increase overall efficiency by studying the concepts of various authors. Different design parameters for a double pipe heat exchange system as well as different working fluid flow rates are tested with the suggested device. Additionally, ANSYS performs computational fluid dynamics for the proposed heat exchanger system in order for the results to support the experimental findings.

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McFARLAND, IAN. "Heat Recovery Apparatus". Heat Transfer Engineering 8, n. 4 (gennaio 1987): 33–35. http://dx.doi.org/10.1080/01457638708962814.

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Zolkowski, Jerry T. "Waste Heat Recovery". Energy Engineering 106, n. 5 (settembre 2009): 63–74. http://dx.doi.org/10.1080/01998590909594544.

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Pile, David F. P. "Waste-heat recovery". Nature Photonics 12, n. 9 (29 agosto 2018): 500. http://dx.doi.org/10.1038/s41566-018-0247-8.

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Richarts, Frit, e Stolberg Breinig. "Heat recovery method". Journal of Heat Recovery Systems 6, n. 1 (gennaio 1986): vii. http://dx.doi.org/10.1016/0198-7593(86)90194-3.

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Khosropour, Mostafa M., e Thomas C. Learn. "Heat recovery muffler". Journal of the Acoustical Society of America 77, n. 6 (giugno 1985): 2206. http://dx.doi.org/10.1121/1.391683.

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Baradey, Y., M. N. A. Hawlader, Ahmad Faris Ismail e Meftah Hrairi. "WASTE HEAT RECOVERY IN HEAT PUMP SYSTEMS: SOLUTION TO REDUCE GLOBAL WARMING". IIUM Engineering Journal 16, n. 2 (30 novembre 2015): 31–42. http://dx.doi.org/10.31436/iiumej.v16i2.602.

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Energy conversion technologies, where waste heat recovery systems are included, have received significant attention in recent years due to reasons that include depletion of fossil fuel, increasing oil prices, changes in climatic conditions, and global warming. For low temperature applications, there are many sources of thermal waste heat, and several recovery systems and potential useful applications have been proposed by researchers [1-4]. In addition, many types of equipment are used to recover waste thermal energy from different systems at low, medium, and high temperature applications, such as heat exchangers, waste heat recovery boiler, thermo-electric generators, and recuperators. In this paper, the focus is on waste heat recovery from air conditioners, and an efficient application of these energy resources. Integration of solar energy with heat pump technologies and major factors that affect the feasibility of heat recovery systems have been studied and reviewed as well.Â KEYWORDS: waste heat recovery; heat pump.

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Wang, Jinshi, Weiqi Liu, Guangyao Liu, Weijia Sun, Gen Li e Binbin Qiu. "Theoretical Design and Analysis of the Waste Heat Recovery System of Turbine Exhaust Steam Using an Absorption Heat Pump for Heating Supply". Energies 13, n. 23 (27 novembre 2020): 6256. http://dx.doi.org/10.3390/en13236256.

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In northern China, many thermal power plants use absorption heat pump to recover low-grade heat from turbine exhaust steam due to the irreplaceable advantages of the absorption heat pump in waste heat recovery. In the process of designing a waste heat recovery system, few researchers have considered the relationship between the design power of the heat pump and the actual heating load of the heating network. Based on the heating load characteristics, this paper puts forward a design idea which uses an absorption heat pump to recover waste heat from a steam turbine exhaust for heating supply. The operation mode of the system for different design powers of the heat pump was stated. An economic analysis model of the waste heat recovery system was proposed, and the optimal design power of the heat pump could be obtained. For a specific unit, the corresponding waste heat recovery system was designed, and various factors affecting the economy of the system were discussed and analyzed in detail.

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Nasif, Mohammad Shakir, e Rafat Al-Waked. "Effect of Air to Air Fixed Plate Enthalpy Energy Recovery Heat Exchanger Flow Profile on Air Conditioning System Energy Recovery". Applied Mechanics and Materials 819 (gennaio 2016): 245–49. http://dx.doi.org/10.4028/www.scientific.net/amm.819.245.

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Fixed plate enthalpy heat exchanger which utilizes permeable material as heat and moisture transfer surface has been used as an energy recovery system to recover sensible and latent heat in HVAC systems. The heat exchanger effectiveness is affected by the air flow profile. It is well known that counter flow configuration provides highest effectiveness, however, in real applications, it is not possible to implement a counter flow configuration, as both inlet and outlet ducts of the two flow streams are located on the same side of the heat exchanger. Therefore, several quasi-counter-flow heat exchanger designs including Z-shaped, L-shaped, Z-shaped opposite flow configurations are proposed in this research and their effect on energy consumed by an air conditioning cooling coil has been investigated, where each of the proposed heat exchanger is incorporated in an air conditioning cooling coil model. The modeled cooling coil energy consumption and energy recovered by the heat exchangers are evaluated under Kuala Lumpur weather conditions. It has been found that an air conditioner coupled with L-shaped heat exchanger recorded up to 20% increase in energy recovery in comparison with Z-shaped oposite and Z-shaped heat exchanger.

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Ungureanu, V. B. "HEAT PIPES FOR HEAT RECOVERY SYSTEMS". Bulletin of the Transilvania University of Brasov. Series I - Engineering Sciences 12(61), n. 2 (7 febbraio 2020): 11–18. http://dx.doi.org/10.31926/but.ens.2019.12.61.1.11.

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Al-Rabghi, O. M., M. Akyurt, Y. S. H. Najjar e T. Alp. "Heat Exchangers for Waste-Heat Recovery". Energy & Environment 4, n. 3 (settembre 1993): 284–306. http://dx.doi.org/10.1177/0958305x9300400305.

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A survey is made of the equipment used for heat recovery and utilization. Types and merits of commonly employed heat exchangers are presented, and criteria for selecting heat exchangers are summarized. Applications for waste heat recovery are emphasized. It is concluded that careful selection and operation of such equipment would be expected to result in energy savings as well as problem-free operation.

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Azad, E. "Split heat pipe heat recovery system". International Journal of Low-Carbon Technologies 3, n. 3 (luglio 2008): 191–202. http://dx.doi.org/10.1093/ijlct/3.3.191.

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OSAKABE, Masahiro. "Heat exchanger for latent heat recovery". Mechanical Engineering Reviews 2, n. 2 (2015): 14–00300. http://dx.doi.org/10.1299/mer.14-00300.

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Rajski, Krzysztof, e Jan Danielewicz. "Heat Transfer and Heat Recovery Systems". Energies 16, n. 7 (5 aprile 2023): 3258. http://dx.doi.org/10.3390/en16073258.

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Touset, Juan Pedro Hernández, e José Ulivis Espinosa Martínez. "Total Site Targeting Approach for Heat Recovery at a Paper Factory". WSEAS TRANSACTIONS ON HEAT AND MASS TRANSFER 18 (31 dicembre 2023): 246–51. http://dx.doi.org/10.37394/232012.2023.18.20.

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The total Site heat integration approach has been used extensively in the industry, including process services and heat exchanger network design integrated with the site service system. This work aims to propose a design for the heat recovery network in the paper factory through Total Site targeting. A procedure that includes the energy analysis and Pinch Analysis methodologies, with the use of Aspen Energy Analyzer is applied. The heat exchanger network design through total site heat integration shows that the rehabilitation of the heat recovery system of the paper machine and boiler blowdown is feasible, with a potential annual saving of 259 t of fuel oil and 116 000 m3 of water, which make it feasible to invest in the factory’s heat recovery system, whose project budget is estimated to recover in a year. Heat exchanger network retrofit design allows to recover 46.2% of the maximum energy recovery.

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Khan, Ershad Ullah, Åke Nordberg e Peter Malmros. "Waste Heat Driven Integrated Membrane Distillation for Concentrating Nutrients and Process Water Recovery at a Thermophilic Biogas Plant". Sustainability 14, n. 20 (19 ottobre 2022): 13535. http://dx.doi.org/10.3390/su142013535.

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To efficiently utilize low-concentrate digestate nutrients, further treatment is needed to decrease their volume, recover process water, and increase nutrient concentrations. Membrane distillation (MD) is a thermally driven process that is advantageous due to its ability to harness low-grade waste heat to treat highly complex wastewater streams. This study assessed the techno-economic performance of integrating MD for two-fold concentrations of nutrients and the recovery of process water from digestate at a thermophilic biogas plant. Thermal assessment showed that the recovered waste heat from flue gas and digestate fully met the thermal energy demand of MD and saved 20% of boiler energy by heating incoming slurry. The permeate flux from MD was 3.5 L/(m2h) and 3.1 L/(m2h) at 66 °C and 61 °C digestate inlet temperatures during winter and summer, respectively. With internal heat recovery, the specific heat demand for MD was 80 kWh/m3 and 100 kWh/m3 in winter and summer, respectively. The unit cost of MD permeate was estimated to be 3.6 €/m3 and 4.1 €/m3 at a digestate feed temperature of 66 °C and 61 °C (with heat recovery), and 7.6 €/m3 and 9.1 €/m3 (without heat recovery) in winter and summer, respectively. However, cost sensitivity analyses showed that waste heat recovery and thermal energy cost variations had a significant impact on the MD permeate production cost. Nevertheless, the economic assessment indicated that the thermal integration of a biogas plant with industrial-scale MD digestate treatment capacity could be economically feasible, with winter being more economically favorable due to higher waste heat recovery.

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Stulc, P., L. L. Vasiliev, V. G. Kiseljev e Ju N. Matvejev. "Heat pipe heat exchangers in heat recovery systems". Journal of Heat Recovery Systems 5, n. 5 (gennaio 1985): 415–18. http://dx.doi.org/10.1016/0198-7593(85)90172-9.

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Nakata, Hiroki, Ryusuke Kakigi e Manabu Shibasaki. "Effects of passive heat stress and recovery on human cognitive function: An ERP study". PLOS ONE 16, n. 7 (20 luglio 2021): e0254769. http://dx.doi.org/10.1371/journal.pone.0254769.

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Using event-related potentials (ERPs), we investigated the effects of passive heat stress and recovery on the human cognitive function with Flanker tasks, involving congruent and incongruent stimuli. We hypothesized that modulation of the peak amplitude and latency of the P300 component in ERP waveforms would differ with task difficulty during passive heat stress and recovery. Subjects performed the Flanker tasks before (Pre), at the end of whole body heating (Heat: internal temperature increase of ~1.2°C from the pre-heat baseline), and after the internal temperature had returned to the pre-heat baseline (Recovery). The internal temperature was regulated by a tube-lined suit by perfusing 50°C water for heat stress and 25°C water for recovery immediately after the heat stress. Regardless of task difficulty, the reaction time (RT) was shortened during Heat rather than Pre and Recovery, and standard deviations of RT (i.e., response variability) were significantly smaller during Heat than Pre. However, the peak amplitudes of the P300 component in ERPs, which involved selective attention, expectancy, and memory updating, were significantly smaller during Heat than during Pre, suggesting the impairment of neural activity in cognitive function. Notably, the peak amplitudes of the P300 component were higher during Recovery than during Heat, indicating that the impaired neural activity had recovered after sufficient whole-body cooling. An indicator of the stimulus classification/evaluation time (peak latency of P300) and the RT were shortened during Heat stress, but such shortening was not noted after whole-body cooling. These results suggest that hyperthermia affects the human cognitive function, reflected by the peak amplitude and latency of the P300 component in ERPs during the Flanker tasks, but sufficient treatment such as whole-body cooling performed in this study can recover those functions.

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Zhao, Yanan, Mingliang Li, Rui Long, Zhichun Liu e Wei Liu. "Advanced adsorption-based osmotic heat engines with heat recovery for low grade heat recovery". Energy Reports 7 (novembre 2021): 5977–87. http://dx.doi.org/10.1016/j.egyr.2021.09.007.

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Wu, J. Y., R. Z. Wang e Y. X. Xu. "Dynamic analysis of heat recovery process for a continuous heat recovery adsorption heat pump". Energy Conversion and Management 43, n. 16 (novembre 2002): 2201–11. http://dx.doi.org/10.1016/s0196-8904(01)00158-3.

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Fialko, N., A. Stepanova, R. Navrodska, N. Meranova e S. Shevchuk. "COMPARATIVE ANALYSIS OF EXERGETIC EFFICIENCY OF HEAT RECOVERY SYSTEMS OF BOILER PLANTS". Energy and automation 2023, n. 3 (2023): 17–27. http://dx.doi.org/10.31548/energiya3(67).2023.017.

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The paper presents the results of a comparative analysis of the exergetic efficiency of heat recovery systems of boiler plants. The need to ensure the efficient operation of heat recovery systems for various purposes determines the importance and relevance of research conducted in this field. The purpose of the work is to increase the exergetic efficiency of heat recovery systems of various purposes. The results of solving the tasks necessary to achieve the set goal are given: - submit heat utilization systems of various purposes in the form of structural diagrams with the identification of exergetic flows of heat carriers; - choose exergetic efficiency evaluation criteria for heat recovery systems of various purposes, calculate their values and conduct a comparative analysis; - develop recommendations for the use of heat recovery systems for various purposes, taking into account the specifics of their application. For research, a complex methodology was used, which combines structural-variant methods of exergetic analysis with methods of presenting exergetic balances in matrix form. Three types of heat recovery systems with different numbers of consumers of recovered heat were considered. Structural diagrams of heat recovery systems of various purposes with identification of exergetic flows of heat carriers between individual discrete elements have been developed. Exergetic losses, thermal exergetic criterion and exergetic efficiency were selected as criteria for evaluating exergetic efficiency. Their values were obtained for heat recovery systems and their elements at different values of the relative power of the boiler. The largest exergy losses occur in the water-heating heat exchanger, smoke extractor and pumping system, the smallest - in the air-heating heat exchanger and gas heater. An increase in the relative power of the boiler leads to an increase in the relative contribution of the exergy losses of the water heating heat recovery system, as well as the pumping system and the pipeline system to the total exergy losses in the heat recovery system. It has been established that increasing the number of consumers of recovered heat in the heat recovery system and using rational ways of reducing total exergy losses increases the efficiency of heat recovery systems. Further developments in this field will allow to increase the exergetic efficiency of heat recovery systems for various purposes.

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Mohd Yusoff, Mohd Hizami, Ein K. Nyunt, Muhammad Roil Bilad, Nasrul Arahman, Sri Mulyati, Samsul Rizal, Nik Abdul Hadi Nordin, Jia Jia Leam, Asim Laeeq Khan e Juhana Jaafar. "Hybrid Membrane Distillation and Wet Scrubber for Simultaneous Recovery of Heat and Water from Flue Gas". Entropy 22, n. 2 (4 febbraio 2020): 178. http://dx.doi.org/10.3390/e22020178.

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Flue gas contains high amount of low-grade heat and water vapor that are attractive for recovery. This study assesses performance of a hybrid of water scrubber and membrane distillation (MD) to recover both heat and water from a simulated flue gas. The former help to condense the water vapor to form a hot liquid flow which later used as the feed for the MD unit. The system simultaneously recovers water and heat through the MD permeate. Results show that the system performance is dictated by the MD performance since most heat and water can be recovered by the scrubber unit. The scrubber achieved nearly complete water and heat recovery because the flue gas flows were supersaturated with steam condensed in the water scrubber unit. The recovered water and heat in the scrubber contains in the hot liquid used as the feed for the MD unit. The MD performance is affected by both the temperature and the flow rate of the flue gas. The MD fluxes increases at higher flue gas temperatures and higher flow rates because of higher enthalpy of the flue gas inputs. The maximum obtained water and heat fluxes of 12 kg m−2 h−1 and 2505 kJm−2 h−1 respectively, obtained at flue gas temperature of 99 °C and at flow rate of 5.56 L min−1. The MD flux was also found stable over the testing period at this optimum condition. Further study on assessing a more realistic flue gas composition is required to capture complexity of the process, particularly to address the impacts of particulates and acid gases.

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Kamarudin, Norhafiza, Liew Peng Yen, Nurfatehah Wahyuny Che Jusoh, Wai Shin Ho e Jeng Shiun Lim. "Organic rankine cycle and steam turbine for intermediate temperature waste heat recovery in total site integration". Malaysian Journal of Fundamental and Applied Sciences 15, n. 1 (4 marzo 2019): 125–30. http://dx.doi.org/10.11113/mjfas.v15n1.1202.

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The utilization of waste heat for heat recovery technologies in process sites has been widely known in improving the site energy saving and energy efficiency. The Total Site Heat Integration (TSHI) methodologies have been established over time to assist the integration of heat recovery technologies in process sites with a centralized utility system, which is also known as Total Site (TS). One the earliest application of TSHI concept in waste heat recovery is through steam turbine using the popular Willan’s line approach. The TSHI methodologies later were extended to integrate with wide range of heat recovery technologies in many literature, whereby Organic Rankine Cycle (ORC) has been reported to be the one of the beneficial options for heat recovery. In general, the medium to high temperature waste heat is recovered via condensing/backpressure steam turbine, whereas ORC is targeted for recovering the low temperature waste heat. However, it is known that condensing turbine is also able to generate power by condensing low grade steam to sub-ambient pressure, which is comparable with ORC integration. In this work, the integration of ORC and condensing turbine are considered for a multiple-process system to recover intermediate temperature waste heat through utility system. This study presents a numerical methodology to investigate the performance analysis of integration of ORC and condensing turbine in process sites for recovering waste heat from a centralized utility system. A modified retrofit case study is used to demonstrate the effectiveness application of the proposed methodology. The performance of ORC and condensing steam turbine are evaluated with the plant total utility costing as the objective function.

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ASANO, Hitoshi, Junichi FUJIYAMA, Eisaku TSUJIMOTO, Tetsurou HAMADA e Makoto HIROTSU. "F107 DEVELOPMENT OF COMPACT LATENT HEAT RECOVERY HEAT EXCHANGER FOR GAS WATER HEATER IN HOUSEHOLD USE(Heat Exchanger)". Proceedings of the International Conference on Power Engineering (ICOPE) 2009.1 (2009): _1–329_—_1–334_. http://dx.doi.org/10.1299/jsmeicope.2009.1._1-329_.

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Wärff, C., M. Arnell, R. Sehlén e U. Jeppsson. "Modelling heat recovery potential from household wastewater". Water Science and Technology 81, n. 8 (5 marzo 2020): 1597–605. http://dx.doi.org/10.2166/wst.2020.103.

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Abstract There is a strongly growing interest for wastewater heat recovery (WWHR) in Sweden and elsewhere, but a lack of adequate tools to determine downstream impacts due to the associated temperature drop. The heat recovery potential and associated temperature drop after heat recovery on a building level is modelled for a case study in Linköping, Sweden. The maximum temperature drop reaches 4.2 °C, with an annual recovered heat of 0.65 kWh · person−1 · day−1. Wastewater temperature out from the heat exchanger was 18.0 °C in winter at the lowest. The drinking water source type can be an important factor when considering wastewater heat recovery.

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33

Takemoto, Shinji, Kazuhiro Ikeda e Ryuta Konishi. "Waste Heat Recovery (WHR) Systems - Development of Heat Recovery Units for G/E Waste Heat". Marine Engineering 48, n. 5 (2013): 700–702. http://dx.doi.org/10.5988/jime.48.700.

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34

Tao, Zhong Nan, Lian Fa Yang e Ze Qiu Wu. "Research on the Devices of Waste Heat Recovery in Tea Dryer". Advanced Materials Research 482-484 (febbraio 2012): 2161–64. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.2161.

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The waste heat is a great part of energy loss in tea processing. The status of waste heat recovery in tea drying has been reviewed. The characteristics and the application of the devices used to recover the waste heat in tea drying have been introduced, such as the circulating type, the storage type and the exchange type. The drawback of the waste heat recovery devices which exists in tea drying process has been analyzed. And the new device of waste heat recovery in tea dryer has been mentioned.

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35

Saari, Jussi, Ekaterina Sermyagina, Juha Kaikko, Markus Haider, Marcelo Hamaguchi e Esa Vakkilainen. "Evaluation of the Energy Efficiency Improvement Potential through Back-End Heat Recovery in the Kraft Recovery Boiler". Energies 14, n. 6 (11 marzo 2021): 1550. http://dx.doi.org/10.3390/en14061550.

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Sustainability and energy efficiency have become important factors for many industrial processes, including chemical pulping. Recently complex back-end heat recovery solutions have been applied to biomass-fired boilers, lowering stack temperatures and recovering some of the latent heat of the moisture by condensation. Modern kraft recovery boiler flue gas offers still unutilized heat recovery possibilities. Scrubbers have been used, but the focus has been on gas cleaning; heat recovery implementations remain simple. The goal of this study is to evaluate the potential to increase the power generation and efficiency of chemical pulping by improved back-end heat recovery from the recovery boiler. Different configurations of heat recovery schemes and different heat sink options are considered, including heat pumps. IPSEpro simulation software is used to model the boiler and steam cycle of a modern Nordic pulp mill. When heat pumps are used to upgrade some of the recovered low-grade heat, up to +23 MW gross and +16.7 MW net power generation increase was observed when the whole pulp mill in addition to the boiler and steam cycle is considered as heat consumer. Combustion air humidification proved to yield a benefit only when assuming the largest heat sink scenario for the pulp mill.

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36

Zhang, Le, Huixing Zhai, Jiayuan He, Fan Yang e Suilin Wang. "Application of Exergy Analysis in Flue Gas Condensation Waste Heat Recovery System Evaluation". Energies 15, n. 20 (12 ottobre 2022): 7525. http://dx.doi.org/10.3390/en15207525.

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Flue gas condensation heat recovery technology has a good technical and economic performance in industrial exhaust gas waste heat recovery. Thermal efficiency analysis is the traditional analysis method for the flue gas condensation heat recovery system but it cannot reflect the recovered heat degree. Exergy analysis, which can reflect the recovered energy heat degree, was first applied to the evaluation of a flue gas condensation waste heat recovery system in this paper. The calculation method of wet flue gas exergy is more complex as both a heat and mass transfer is presented. Flue gas waste heat exergy efficiency (EE) and the flue gas waste heat exergy utilization rate (EUR) were proposed as the evaluation indexes for exergy analysis. The exergy analysis method was applied to the comparative evaluation of three recovery schemes in a practical project. The results show that when the water vapor content of wet flue gas is less than 10%, the condensed water exergy can be neglected when calculating EE. The EUR could be used as a comprehensive index for comparing different waste heat recovery schemes, and EE could be used to judge whether the energy grade of heat exchange equipment was seriously decreased. Exergy analysis could effectively make up for the deficiency of thermal efficiency analysis that could not reflect the waste heat grade utilization. Exergy analysis and thermal efficiency analysis are recommended to be used simultaneously to make a more comprehensive analysis and evaluation of the system.

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37

KOHLI, UJJAWAL. "Heat Energy Recovery System". Trends in Renewable Energy 4, n. 3 (aprile 2018): 56–63. http://dx.doi.org/10.17737/tre.2018.4.3.0055.

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38

Zebik, Albin, Sandor Baliko e Javier Mont. "Heat Recovery from Industry". Energy Engineering 94, n. 5 (gennaio 1997): 61–72. http://dx.doi.org/10.1080/01998595.1997.10530389.

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39

Harrop, R. F. "Heat recovery in supermarkets". Building Services Engineering Research and Technology 9, n. 3 (agosto 1988): 105–8. http://dx.doi.org/10.1177/014362448800900303.

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40

Yanai, Eiji, e Tetsuzo Kuribayashi. "Waste heat recovery boiler". Atmospheric Environment (1967) 22, n. 2 (gennaio 1988): ii. http://dx.doi.org/10.1016/0004-6981(88)90065-0.

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41

Selvaraj, J., V. S. Varun, Vignesh e Vishnu Vishwam. "Waste Heat Recovery from Metal Casting and Scrap Preheating Using Recovered Heat". Procedia Engineering 97 (2014): 267–76. http://dx.doi.org/10.1016/j.proeng.2014.12.250.

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42

Huang, B. J. "Enameled heat exchanger for heat recovery applications". Heat Recovery Systems and CHP 8, n. 3 (gennaio 1988): 203–10. http://dx.doi.org/10.1016/0890-4332(88)90056-7.

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43

Östbring, Karolina, Emma Malmqvist, Kajsa Nilsson, Ia Rosenlind e Marilyn Rayner. "The Effects of Oil Extraction Methods on Recovery Yield and Emulsifying Properties of Proteins from Rapeseed Meal and Press Cake". Foods 9, n. 1 (24 dicembre 2019): 19. http://dx.doi.org/10.3390/foods9010019.

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The agricultural sector is thought to be responsible for around 30% of the anthropogenic climate change and it is well established that high meat consumption has a tremendous impact on the environment. Rapeseed is mainly used for production of vegetable oil, but press cake has high protein content with the potential for incorporation into new plant protein-based foods. Protein was recovered from press cakes generated from different oil pressing processes. Industrially cold-pressed, hot-pressed, and solvent-extracted rapeseed press cake and the effect of heat treatment in the recovery process was assessed. Protein recovery yield, protein concentration and emulsifying properties were analyzed. Cold-pressed rapeseed press cake (RPC) recovered in the absence of heat, yielded the highest protein recovery (45%) followed by hot-pressed rapeseed meal (RM) (26%) and solvent-extracted RM (5%). Exposure to heat during recovery significantly reduced the yield for cold-pressed RPC but no difference was found for hot-pressed RM. The protein recovery yield was improved for solvent-extracted RM when heat was applied in the recovery process. The ability to stabilize emulsions was highest for protein recovered from cold-pressed RPC, followed by hot-pressed RM and solvent-extracted RM, and was in the same range as commercial emulsifying agents. Heat treatment during recovery significantly reduced the emulsifying properties for all pressing methods examined. This study suggests that cold-pressed rapeseed press cake without heat in the recovery process could be a successful strategy for an efficient recovery of rapeseed protein with good emulsifying properties.

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Zong, Jianfang, Liang Sun, Huiting Guo e Fei Fang. "Research progress of low-temperature heat recovery technology in sulfuric acid production". E3S Web of Conferences 194 (2020): 01001. http://dx.doi.org/10.1051/e3sconf/202019401001.

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Low-temperature waste heat refers to the sum of the heat degraded and transferred to the dry absorption process after the high- and medium-temperature heat is recovered in the conversion process in the conventional sulfuric acid production plant, as well as the sulfuric acid formation heat, steam condensation heat and sulfuric acid dilution heat generated in the dry absorption process. It is of great practical significance to rationally develop and utilize the low-temperature waste heat. This paper introduces the development of traditional waste heat recovery technology and low-temperature heat recovery technology for sulfur-based sulfuric acid production. It also expounds the principle, process technology and main equipment of developing low-temperature heat recovery technology for sulfuric acid production plants at home and abroad, and summarizes the low-temperature heat recovery technology for sulfuric acid production plants.

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45

Teng, Da, Ang Li, Tielin Li, Liansuo An, Guoqing Shen e Shiping Zhang. "Experimental study on waste heat recovery characteristics of inorganic ceramic membrane flue gas". Thermal Science and Engineering 5, n. 1 (10 maggio 2022): 51. http://dx.doi.org/10.24294/tse.v5i1.1529.

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The wet saturated flue gas discharged by coal-fired utility boilers leads to a large amount of low-temperature wasteheat loss. Inorganic ceramic membrane is acid-base resistant and has strong chemical stability. It is an ideal material forrecovering low-temperature waste heat from flue gas. The experiment of waste heat recovery of flue gas was carried outwith inorganic ceramic membrane as the core, and the characteristic parameters of low-temperature flue gas at the tailof the boiler were analyzed; taking 316 L stainless steel as the comparative object, the strengthening effect of inorganicceramic film on improving heat recovery power and composite heat transfer coefficient was discussed. The results showthat the waste heat recovery of flue gas is mainly the evaporation latent heat recovery of water, accounting for about90%; circulating water is used as cooling medium, and the waste heat recovery capacity of flue gas is stronger;compared with circulating water, when air is used as the cooling medium, the effect of inorganic ceramic membraneflue gas waste heat recovery is more significant, and the enhancement coefficient is as high as 9; increasing the flue gasflow is helpful to improve the heat recovery power and composite heat transfer coefficient; at the same time, inorganicceramic membrane can also recover condensate with high water quality. The results of this paper can provide areference for the application of inorganic ceramic membrane in flue gas waste heat recovery.

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46

Wipplinger, KPM, TM Harms e AB Taylor. "Stainless steel finned tube heat exchanger design for waste heat recovery". Journal of Energy in Southern Africa 17, n. 2 (1 maggio 2006): 47–56. http://dx.doi.org/10.17159/2413-3051/2006/v17i2a3281.

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Around the world the implementation of heat recovery systems play an increasingly important role in the engineering industry. Recovered energy is utilised in production plants (especially in the food industry) and saves companies millions in expenses per year. Waste heat recovery associated with hydrocarbon combustion in the transport industry is identified as a significantly under-utilised energy resource. The aim of this project was to investigate the recovery of waste heat in a small scale system for the purpose of electrical conversion in order to serve as a secondary energy source. A theoretical analysis concerning the design and construction of the system, utilising researched theory and a control-volume-based simulation program of the recovery system, is presented. It was found that heat exchangers for the required duty are not readily available in South Africa. A high pressure, cross flow, stainless steel finned tube heat exchanger with a water side pressure rating of 2 MPa was therefore designed and constructed. By using the exhaust gases of a continuous combustion unit as an energy source and water as the working fluid, efficiencies of up to 74% in direct steam generation testing were obtained.

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47

Zhang, Xi Liang, Jun Xu, Li Qiang Chen e Ai Xin Feng. "Design of Grate Bed Heat Recovery Unit and Simulation Analysis". Key Engineering Materials 464 (gennaio 2011): 366–69. http://dx.doi.org/10.4028/www.scientific.net/kem.464.366.

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For the current problem that grate bed can not recover its own waste heat in the course of cycle working, combined with the structure of the chain grate and hot air flow process, a three-section heat recovery unit of grate bed and waste heat recovery hot air flow process are designed. According to the principle of repeated convective heat transfer, the amount of recovering waste heat of heat recovery unit is estimated, and simulation analysis is conducted by using fluent software. The results show: after three heat exchange between the hot exhaust gas at around 100°C and the grate bed, the hot gas at a temperature of around 427 °C can be obtained, and the waste heat recovery rate is above 60%; simulation results are compared with the estimated value so that it can be obtained that the differences between the two values in the temperature of three-section outlet gas are basically consistent, about 8°C, 4°C, 7°C respectively, which verifies the effectiveness of the heat recovery unit design and the accuracy of Fluent simulation.

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48

Ergul, Murat, e Selcuk Selimli. "An applied study on energy analysis of a coke oven". Science and Technology for Energy Transition 79 (2024): 1. http://dx.doi.org/10.2516/stet/2023042.

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In this study, the energy view of an oven of a 70-oven coke battery in an iron and steel plant was evaluated based on operating parameters and recommendations for improving efficiency were made. A mass and energy balance per coking period (p) was created for a coke oven. It was found that during each coking period, 51.2% of the energy input was used as coking heat. It is predicted that approximately 6.91% of the input energy can be recovered from flue gas into the combustion air. By recovering the heat from the flue gas into the combustion air, the efficiency of the coke oven can be increased to 58.11%. The heat of the coke oven gas can be recovered and converted into usable form, which accounts for 6.53% of the total energy input. With the dry quenching process, it is possible to recover around 24% of the energy used from coke. Improved oven insulation, heat recovery from coke and flue gases, and the dry quenching process can recover energy worth more than 25.19 GJ/p. The energy efficiency of the furnace was predicted to rise to 82.11% with coke dry quenching and to more than 88.64% with coke gas heat recovery and insulation upgrades. The potential economic savings are $2578, equivalent to a reduction in CO₂ emissions of 2.45 tons per coking period. The financial equivalent of emissions reductions from carbon trading could be $233 per coking period. Through the processes of dry coke quenching, coke gas (CG), and flue gas heat recovery and thermal insulation improvements of the coke battery, the total amount of recoverable energy can exceed 617,294 GJ/year.

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Karmazyn, M., K. Mailer e R. W. Currie. "Acquisition and decay of heat-shock-enhanced postischemic ventricular recovery". American Journal of Physiology-Heart and Circulatory Physiology 259, n. 2 (1 agosto 1990): H424—H431. http://dx.doi.org/10.1152/ajpheart.1990.259.2.h424.

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Hyperthermia induces the synthesis of the 71-kDa heat-shock protein (heat-shock response) in all rat tissues, including heart. We examined whether induction of the heat-shock response alters the response of isolated hearts to ischemia and reperfusion. Anesthetized male rats were pretreated with 15 min of hyperthermia (42 degrees C) and then recovered for 0, 24, 48, 96, or 192 h. Hearts were isolated from control and hyperthermia-treated rats and retrogradely perfused. Greatest recovery occurred in 48-h postheat-shock hearts; after 30 min of reperfusion there was a 38, 62, and 62% recovery of force, +dF/dt, and -dF/dt, respectively, and 17, 36, and 30% recovery, respectively, for the control hearts. Creatine kinase efflux during reperfusion was reduced by 75% for 24-h postheat-shock hearts. The antioxidative enzyme catalase was increased 24, 48, and 96 h posthyperthermia. Treatment of rats with 3-amino-1,2,4-triazole (1 g/kg body wt), which irreversibly inactivates catalase, 30 min before isolation of hearts, abolished the hyperthermia-induced enhancement of postischemic recovery. These results show a strong relationship between the acquisition and decay of the enhanced postischemic ventricular recovery and the hyperthermic induction of the heat-shock response indicated by the accumulation of heat-shock protein HSP71 (mol mass 71 kDa) and the increase in catalase activity.

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50

Gadle, Manishkumar. "Review of Heat Pipe Heat Exchangers in HVAC and R Systems". Journal of Mechanical and Construction Engineering (JMCE) 3, n. 2 (2023): 1–7. http://dx.doi.org/10.54060/jmce.2023.45.

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The domain of Waste Heat Recovery is particularly crucial for countries facing energy consumption deficiencies. Stringent environmental regulations act as a catalyst, propelling the evolution of innovative technologies and equipment. Striking a balance between economically viable, technically feasible, and environmentally sound waste heat recovery methods is imperative, extending beyond Air Conditioners to encompass various processes. Swift advancements are required to effectively recover waste heat from diverse processes. HVAC systems, like many engineering systems, generate waste heat that holds the potential for recovery and reuse in alternative applications. This study focuses on exploring noble recovery methods, utilizing hot air reclaimed from the condenser of an HVAC system, determined through mass and energy balance considerations. Numerous experimental and theoretical investigations have been undertaken on High-Performance Heat Exchangers (HPHE) since Akachi first proposed them in 1990. However, due to the intricate interplay of hydrodynamics and thermodynamics, the operational mechanism of HPHE remains highly complex and not entirely elucidated. With high expectations for HPHE applications in the HVAC and Refrigeration (R) sector, this paper undertakes a comprehensive review of its development. It systematically summarizes the latest findings from both experimental and theoretical studies, with a specific focus on the HVAC and R field. Additionally, the paper highlights promising and innovative applications of HPHE. The intention is to furnish a foundational reference for future research endeavors in this evolving field.

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