•A brief review on application of nanofluid in heat exchangers.•Presenting a review on nanofluids and their simulation methods.•Presenting studies on different heat exchangers including: plate, ...helical, shell and tube and double-tube.•Trying to understand the mechanisms of heat transfer in the field of using nanofluids in heat exchangers.•Nanofluids reduce volume of heat exchangers and improve saving energy.
In this paper a brief review on application of nanofluids in heat exchangers has been addressed. One of the barriers to increase the capacity of different industries is the lack of response of heat devices in higher capacities. In addition, increasing capacity leads to an increase in pressure drop and this is one of the most important restrictions on the large industries. Conventional methods of increasing heat transfer greatly increase the pressure drop, and according to the results of previous studies, using the special nanofluids, the thermal efficiency of the heat exchanger can be increased significantly, which is one of the most important thermal devices in the industry. In this research, firstly a review of nanofluids studies and introduction of nanofluids is presented, then their simulation methods are investigated, and finally, studies on the used tubes in the heat exchangers have been investigated, and studies of the plate heat exchanger, helical heat exchanger, shell and tube heat exchanger, and double-tube heat exchanger have been examined. The enhancement of thermal and hydraulic performance of heat exchangers is very important in terms of energy conversion, and also is important in the economic recovery of systems through savings. This paper examines previous studies on heat exchangers and using of nanofluids in them. The purpose of the paper is not only to describe the previous studies, but also to understand the mechanisms of heat transfer in the field of using nanofluids in heat exchangers, and also to evaluate and compare different heat transfer techniques. Finally, it can be concluded that the nanofluids in most cases improve heat transfer, which reduce the volume of heat exchangers, saving energy, consequently water consumption and industrial waste.
In the countries with tropical climates such as Malaysia, humidity and hot weather are well-regarded; this weather can affect the heat conditions and indoor room. The effects of the poor thermal ...condition are non-conducive human activities and a comfortable environment in the room. They improved the tilt angle for roof building or house design with insulation to achieve comfort and reduce the indoor temperature. Thermal insulation is one of the methods to reduce heat transmission through the room by applying proper material and installation. The main objective of this study is to test Glasswool insulation in different orientations of the roof for Malaysian houses. The insulation material has been tested by airflow simulation using SolidWorks software which applies to the rooftop on the east and west orientations, where the indoor temperature of the house has been reduced from (29°C - 27°C East and 30°C - 28°C West) without considering any air movement. The simulation result shows the temperature reduction before and after applying the insulation corresponds, while the reduction is 2°C temperature (7.4% reduction) at both orientations. The significant reduction helped the occupants to reach their comfort zone and save the cost of the electrical bill.
Bio-based protic ionic liquids (bio-PILs) based on 2,5-Furandicarboxylic acid and polyetheramine was synthesized, which was explored as a neat lubricant and lubricant additive for different alcohols ...that has different hydroxyl numbers under varied test conditions. Long-term service performance testing showed that the bio-PILs could achieve ultra-low coefficient of friction and wear simultaneously, which decreased coefficient of friction of 95.94% and wear rate of 99.87% compared to dry friction under Si3N4-to-steel tribo-pairs. The distinguished tribological performance is contributed to the bio-PILs can absorb on the rubbing surface and form a lubricating protective film to avoid direct contact of super hard upper Si3N4 ball against lower steel plate. This work presents a facile approach to synthesize high-performance bio-based protic ionic liquids using biomass as bridging agent and provides new insight into the underlying lubricating mechanism, which might help guide the development of novel bio-based lubricants in the future.
•The 2,5-Furandicarboxylic derived bio-based protic ionic liquids (bio-PILs) was synthesized and identified.•The bio-PILs shows excellent thermal stability and anti-corrosion property.•Excellent friction reduction (95.94%) and anti-wear performance (99.87%) was obtained simultaneously by bio-PILs.•Ultra-low wear rate (5.4305 × 10−18 m3/N m) was achieved under ceramic-to-steel contact.
•Lighting aspects to implement a sustainable daylight performance in public buildings.•Daylight Strategies as Part of Nearly Zero-Energy Design Framework.•Integrated pathways related to architectural ...environment improvement.•Human eyesight system optimization for visual economy as a model of sustainability.
Many towns and villages around the world have implemented new technologies within lighting recently because there is an urgent need to save electricity, operational and maintenance costs. Taking into account recent global issues such as global warming, climate change, COVID-19 and increasing electricity bills, many countries have changed their plans for saving electricity by implementing more efficient, sustainable strategies. A global perspective and classification of the main lighting aspects necessary to implement sustainable daylight performance in public buildings is presented here. Qualitative research methodology is utilized in this article in order to clarify how daylighting strategies in public buildings contribute to the achievement of sustainable daylight performance. Objectives for achieving integrated pathways for sustainable development are detailed, related to natural lighting environment improvement, architecture, style and human health, and supported by a balanced organizational structure in order to achieve zero-energy buildings. The article also emphasizes the significance for the future of ensuring acceptable lighting through best lighting practices, providing advice through optimal lighting strategies in an efficient, realistic and responsible way. This lighting approach will serve to help in achieving nearly zero-energy buildings as a form of sustainably designed buildings. Finally, the article summarizes the most appropriate techniques for improving the daylight performance in public buildings, and an optimized human eyesight system is presented, based on the visual economy as a model of sustainability.
The high share of buildings in energy consumption and carbon dioxide emission has led researchers to seek techniques to reduce energy consumption in this sector. In this study, considering a hot and ...arid climate region, the wall’s heat gain was investigated. To reduce energy demand, three techniques of adding PCM, combining absorption chiller with a solar system and dispersing nanoparticles were used and the results were evaluated transiently. In July, the addition of PCM to the building's walls reduced the heat exchange between interior and exterior spaces up to 21%. To cool the interior spaces, the combination of absorption chiller + fan coil was used and several flat plate collectors were integrated with it to reduce energy demand. By collecting energy in solar collectors and using a stratified tank, energy consumption in the generator section was reduced by 450 kWh. Nanoparticles were used to improve the solar system performance and it was found that loading ZnO and Al
2
O
3
nanoparticles is useful. Dispersing ZnO into water increased the energy-saving by 9.5% while the second nanoparticle improved it by 14.5%.
•Investigated WCP incorporated AAMs using FA as replacement of GBFS.•FA content strongly influenced the mechanical and durability properties of AAMs.•Enhance AAMs durability to acid and sulphate ...attacks with increased FA content.•Resistance of AAMs to freezing-thawing was inversely related to FA contents.•Ability to produce sustainable AAMs by incorporating WCP, GBFS and FA.
Traditional Portland cement can be effectively substituted by alkali-activated binders. Not only can alkali-activated binders save energy and reduce CO2 emission but they can also augment the durability performance of concrete as well as aid in resolving the landfill problems. It is well-known that extensive quantities of calcined clay waste are created every year by the ceramic industry, of which a significant amount is used in landfills. It is thus more appropriate to reuse this waste efficiently. This study investigated the impacts on sustainability of waste ceramic tile powder (WCP) based alkali-activated mortars (AAMs) incorporating fly ash (FA) as a replacement of ground blast furnace slag (GBFS), which were exposed to various hostile environments. Binders were prepared by maintaining the WCP content at 50% in all alkali-activated mortars (AAMs) and FA replacing GBFS by 10%, 20%, 30%, and 40%. Durability properties were evaluated which included elevated temperatures, sulphate and acid attack, drying shrinkage, freezing-thawing and wet-dry cycles, as well as water permeability. The findings suggested that freezing-thawing resistance increased and better durability was displayed by increasing the FA content in AAMs. Furthermore, AAMs with high FA content led to enhance the performance in terms of sulphate and acid environments and elevated temperatures. Apart from the increased durability, replacing GBFS with FA also resulted in decreased energy consumption, AAMs cost, and CO2 emission.
Ensuring the effective thermal insulation in regions, where the cooling requirement of building with respect to heating requirement is dominant, is very important from the aspect of energy economy. ...In this study, the influence of thermal insulation on the building cooling load and the cooling system in case of air-conditioning by an all-air central air-conditioning system was evaluated for a sample building located in Adana, based on the results of three different types of insulation (A, B and C-type buildings) according to the energy efficiency index defined in the Thermal Insulation Regulation used in Turkey. The operating costs of the air-conditioning system were calculated using cooling bin numbers. Life-cycle cost analysis was carried out utilizing the present-worth cost method. Results showed that both the initial and the operating costs of the air-conditioning system were reduced considerably for all three insulation thicknesses. However, the optimum results in view of economic measurements were obtained for a C-type building. The thickness of thermal insulation for the buildings in the southern Turkey should be determined according to the guidelines for a C-type building.
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•Simulating the pressurized catalytic reforming process of waste tires with Aspen Plus.•Giving a new saving energy process of waste tires pressurized pyrolysis.•Combustion of exhaust ...gases provided energy for the pyrolysis and reforming furnace.•Evaluating the energy and exergy efficiency of the pressurized catalytic reforming process.•The exergy loss rate of the whole simulation system was 5.51%.
The pressurized catalytic reforming technology had a positive impact on product quality, but the energy consumption for industrial applications remained uncertain. To achieve the need for energy-efficient and environmentally-friendly conversion of waste tires, this study developed a system of pressurized catalytic reforming and exhaust gas combustion to produce high-quality oil, char, and industrial steam. The process was analyzed and evaluated based on the energy and exergy balance. The simulation results closely matched the experimental results, demonstrating the accuracy of the developed model. Significant energy savings were realized in the pyrolysis unit at 2.82 GJ/h and reforming unit at 7.57 GJ/h, respectively. The energy loss rates of the pyrolysis unit, heat transfer for the industrial steam unit, reforming unit, and combustion unit were 2.77%, 5.24%, 0.75%, and 0.77% of the system input energy, respectively. In addition, the heat transfer for the industrial steam unit recovered 12.93% of the system input energy. The exergy loss rates of the pyrolysis reactor, combustion reactor, and heat exchanger HEATER6 in the whole simulation system were 38.91%, 12.07%, and 32.29%, respectively.
Accelerated population growth and urbanization have negative environmental impacts, such as habitat destruction, biodiversity loss, natural resource depletion, and pollution. They speed up climate ...change, contribute to urban heat islands, and increase energy use. Green roofs (GRs) can reduce the ecological footprint and improve the quality of life within cities but require careful design for best results. This study analyzes the thermal performance of GRs in six experimental modules differing in roof cover: concrete, reflective coating, dry soil, wet soil, traditional GR with Sedum acre, and wetland GR with Salicornia pacifica. The two plant species have different carbon assimilation metabolisms: S. pacifica is a native wetland C3 species with diurnal transpiration that grows in flooded soils, and S. acre is an exotic Crassulacean Acid Metabolism (CAM) species with night-time transpiration, commonly used in GRs. GRs were monitored during the winter of 2020 in Ensenada, Baja California, México, a city with a semi-arid Mediterranean climate. We found that vegetated covers reduced the temperature oscillation with an insulating effect. During the warmest week, they reduced the internal roof surface temperature (Ts,in) up to 12.4 °C in comparison to the concrete roof. They maintained Ts,in up to 5.8 °C warmer than concrete roof during the coldest week, indicating that GRs are efficient thermal regulators in this region, potentially reducing buildings’ thermal load as well as providing additional ecosystemic services. Since S. pacifica had higher survival and coverage, we recommend its use in GRs located in Northwest Mexico and climatically similar world regions.
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•A green roof with wetland C3 plants was proposed and evaluated.•Native species had higher survival and coverage than exotic species.•A wetland roof showed a better thermal behavior than a traditional roof.•Green roof inner temperature was up to 5.8 °C higher than concrete roof.•A wetland roof reduces the thermal load up to 39% compared to a concrete roof.
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