Energy distribution function based universal adsorption isotherm model for all types of isotherm

Based upon the adsorbate-adsorbent interactions due to pore size distribution and surface heterogeneity, as characterized by the adsorption isotherms, the adsorption phenomenon has many industrial and environmental applications. These adsorption isotherms are very important to define the information related to the equilibrium uptake of adsorbate-adsorbent pair. Due to the presence of different energy distribution of adsorption sites, pore size distribution, surface area availability and surface heterogeneity, of each of the adsorbent-adsorbate pair, these isotherms are categorized into six types by the International Union of Pure and Applied Chemistry and so far, in the literature, there is no generalized adsorption isotherm model available that can define and predict the behavior of all adsorption isotherm types. In this study, a universal adsorption isotherm model is developed based upon the energy distribution function of the available adsorption sites and the pore size. The proposed model is able to define all adsorption isotherm characteristics, irrespective of their multi- or monolayer formations and micro- or meso-pore distribution

Hydrogen at the rooftop: Compact CPV-hydrogen system to convert sunlight to hydrogen

Despite being highest potential energy source, solar intermittency and low power density make it difficult for solar energy to compete with the conventional power plants. Highly efficient concentrated photovoltaic (CPV) system provides best technology to be paired with the electrolytic hydrogen production, as a sustainable energy source with long term energy storage. However, the conventional gigantic design of CPV system limits its market and application to the open desert fields without any rooftop installation scope, unlike conventional PV. This makes CPV less popular among solar energy customers. This paper discusses the development of compact CPV-Hydrogen system for the rooftop application in the urban region. The in-house built compact CPV system works with hybrid solar tracking of 0.1° accuracy, ensured through proposed double lens collimator based solar tracking sensor. With PEM based electrolyser, the compact CPV-hydrogen system showed 28% CPV efficiency and 18% sunlight to hydrogen (STH) efficiency, for rooftop operation in tropical region of Singapore. For plant designers, the solar to hydrogen production rating of 217 kWhe/kgH2 has been presented with 15% STH daily average efficiency, recorded from the long term field operation of the syste

Desalination Processes’ Efficiency and Future Roadmap

For future sustainable seawater desalination, the importance of achieving better energy efficiency of the existing 19,500 commercial-scale desalination plants cannot be over emphasized. The major concern of the desalination industry is the inadequate approach to energy efficiency evaluation of diverse seawater desalination processes by omitting the grade of energy supplied. These conventional approaches would suffice if the efficacy comparison were to be conducted for the same energy input processes. The misconception of considering all derived energies as equivalent in the desalination industry has severe economic and environmental consequences. In the realms of the energy and desalination system planners, serious judgmental errors in the process selection of green installations are made unconsciously as the efficacy data are either flawed or inaccurate. Inferior efficacy technologies' implementation decisions were observed in many water-stressed countries that can burden a country's economy immediately with higher unit energy cost as well as cause more undesirable environmental effects on the surroundings. In this article, a standard primary energy-based thermodynamic framework is presented that addresses energy efficacy fairly and accurately. It shows clearly that a thermally driven process consumes 2.5-3% of standard primary energy (SPE) when combined with power plants. A standard universal performance ratio-based evaluation method has been proposed that showed all desalination processes performance varies from 10-14% of the thermodynamic limit. To achieve 2030 sustainability goals, innovative processes are required to meet 25-30% of the thermodynamic limit

Desalination Processes’ Efficiency and Future Roadmap

For future sustainable seawater desalination, the importance of achieving better energy efficiency of the existing 19,500 commercial-scale desalination plants cannot be over emphasized. The major concern of the desalination industry is the inadequate approach to energy efficiency evaluation of diverse seawater desalination processes by omitting the grade of energy supplied. These conventional approaches would suffice if the efficacy comparison were to be conducted for the same energy input processes. The misconception of considering all derived energies as equivalent in the desalination industry has severe economic and environmental consequences. In the realms of the energy and desalination system planners, serious judgmental errors in the process selection of green installations are made unconsciously as the efficacy data are either flawed or inaccurate. Inferior efficacy technologies' implementation decisions were observed in many water-stressed countries that can burden a country's economy immediately with higher unit energy cost as well as cause more undesirable environmental effects on the surroundings. In this article, a standard primary energy-based thermodynamic framework is presented that addresses energy efficacy fairly and accurately. It shows clearly that a thermally driven process consumes 2.5-3% of standard primary energy (SPE) when combined with power plants. A standard universal performance ratio-based evaluation method has been proposed that showed all desalination processes performance varies from 10-14% of the thermodynamic limit. To achieve 2030 sustainability goals, innovative processes are required to meet 25-30% of the thermodynamic limit

A multi evaporator desalination system operated with thermocline energy for future sustainability

All existing commercial seawater desalination processes, i.e. thermally-driven and membrane-based reverse osmosis (RO), are operated with universal performance ratios (UPR) varying up to 105, whilst the UPR for an ideal or thermodynamic limit (TL) of desalination is at 828. Despite slightly better UPRs for the RO plants, all practical desalination plants available, hitherto, operate at only less than 12% of the TL, rendering them highly energy intensive and unsustainable for future sustainability. More innovative desalination methods must be sought to meet the needs of future sustainable desalination and these methods should attain an upper UPR bound of about 25 to 30% of the TL. In this paper, we examined the efficacy of a multi-effect distillation (MED) system operated with thermocline energy from the sea; a proven desalination technology that can exploit the narrow temperature gradient of 20 °C all year round created between the warm surface seawater and the cold-seawater at depths of about 300–600 m. Such a seawater thermocline (ST)-driven MED system, simply called the ST-MED process, has the potential to achieve up to 2 folds improvement in desalination efficiency over the existing methods, attaining about 18.8% of the ideal limit. With the major energy input emanated from the renewable solar, the ST-MED is truly a “green desalination” method of low global warming potential, best suited for tropical coastal shores having bathymetry depths of 300 m or more

Energy-water-environment nexus underpinning future desalination sustainability

Energy-water-environment nexus is very important to attain COP21 goal, maintaining environment temperature increase below 2 °C, but unfortunately two third share of CO2 emission has already been used and the remaining will be exhausted by 2050. A number of technological developments in power and desalination sectors improved their efficiencies to save energy and carbon emission but still they are operating at 35% and 10% of their thermodynamic limits. Research in desalination processes contributing to fuel World population for their improved living standard and to reduce specific energy consumption and to protect environment. Recently developed highly efficient nature-inspired membranes (aquaporin & graphene) and trend in thermally driven cycle's hybridization could potentially lower then energy requirement for water purification. This paper presents a state of art review on energy, water and environment interconnection and future energy efficient desalination possibilities to save energy and protect environment

Approaches to Energy Efficiency in Air conditioning: Innovative processes and thermodynamics

Air conditioning in buildings has transformed our human lives greatly with work efficiency in commercial buildings and improved lifestyle in all weather. However, these improvements are accompanied with the negative effects from the emissions of greenhouse gases (GHG), both directly via refrigerant emissions and indirectly through electricity generation by the burning of fossil fuels. Although there were significant improvements in the efficacy of chillers since 2000, the kW/Ron of chillers for cooling for electrically driven DCS have reached an asymptotic level of 0.85±0.03 kW/Rton for the tropics and a 20% higher for the hot and dry arid climate. The levelling-off phenomenon of chillers' energy efficiency is attributed the improvements limits exploited from the efficacy of compressor and refrigerant technologies. Thus, an out-of-box solution, such as the decoupling of latent to sensible cooling in the dehumidification cum the indirect evaporative coolers (DH-IEC) to improve energy efficiency, It is projected that a quantum jump of 0.5 kWh/m3 or less is urgently needed for future sustainable cooling. In this paper, we adopted a top-down approach in evaluating the upper-bound energy savings of an economy if one were to employ the innovative DH-IEC cycle is assumed to be applied to the Singapore city state is highlighted with respect to the savings in the primary energy, emission of CO2 and the water savings of up to 40 % can be potentially achieved

Pengembangan Model Tata Kelola Link and Match Berbasis Industri untuk Meningkatkan Kompetensi Siswa pada SMK Bidang Teknologi dan Rekayasa ; Development of Industry Based Link and Match Management Model to Improve SMK Students’ Competency on Technology and Engineering

ABSTRAK Tujuan penelitian ini adalah untuk mengetahui (1) Gambaran model tata kelola link and match pada sekolah menengah kejuruan saat ini, (2) pengembangan model tata kelola link and match berbasis industri pada sekolah menegah kejuruan yang valid, praktis dan menarik, (3) Mengetahui keefektifan model tata kelola link and match berbasis industri. Penelitian ini menggunakan pendekatan penelitian pengembangan atau jenis penelitian Research and Development (R&D) dengan merujuk pada model Borg and Gall (2007) dan ADDIE. Model Produk yang dikehendaki dalam penelitian ini adalah sebuah model tata kelola link and match berbasis industri pada sekolah menengah kejuruan bidang teknologi dan rekayasa yang merupakan konsep pelaksanaan Praktek KerjaIndustri (Prakerin) yang kemudian disebut Model IB-LAM untuk memaksimalkan hasil pelaksanaan Prakerin dengan meningkatkan Kompetensi Keahlian/Industri siswa serta nilai employability skill dan karakter di dalamnya dengan beberapa perangkat pendukung. Penelitian ini dilakukan pada siswa yang melaksanakan prakerin pada industri di Kabupaten Pangkep. Subjek penelitian sebanyak 30 orang. Analisis data yang digunakan adalah analisis data pada tahap studi pendahuluan, analisis data pada tahap pengembangan model, dan analisis data pada tahap evaluasi model. Analisis kevali dan oleh ahli, analisis kepraktisan model, analisis kemenarikan model, dan analisis uji efektifitas berdasarkan hasil penerapan model. Hasil penelitian dan pengembangan dapat disimpulkan: (1) model tatakelola link and match (Pelaksanaan Prakerin) selama ini dilaksanakan cenderung tidak melalui konsep pengelolaan yang maksimal, kurangnya pembekalan yang dilakukan, kurangnya perhatian orang tua siswa, kurangnya guru bidang studi produktif (kejuruan), serta belum adanya panduan pembimbing dan metode penilaian prakerin yang sistematis dan terukur sehingga pelaksanaan prakerin berjalan tanpa memperhatikan kompetensi dan nilai-nilai karakter yang dapat dikembangkan selama penyelenggaraan praktek kerja industri. (2) Model IB-LAM yang dikembangkan memenuhi persyaratan kevalidan, praktis, dan menarik. (3) Hasil uji efektifitas melalui uji kompetensi menunjukkan bahwa terjadi peningkatan yang signifikan pada pengetahuan dan kompetensi industri siswa sebelum dan sesudah mengikuti prakerin dengan model IB-LAM. Dengan demikian dapat disimpulkan bahwa model tata kelola link and match (Pelaksanaan Prakerin) IB-LAM efektif dalam meningkatkan kompetensi Industri pada siswa. Kata kunci: Tata kelolaLink and Match, Kompetensi Siswa, Sekolah Menengah Kejurua