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

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

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

Home Away From Home

This application is an e-Commerce platform. Where customers can Search for a home for a temporary stay as a rental vacation. This online application allows the owners to update their properties and lease them to renters. This web application has user-friendly functionalities providing facilities to the renters, owners, and administrators. This platform will be categorized based on the type of dwelling, property address (Zip/state/county) and price range. A user can search properties based on these categories. This will replace a manual system that uses a lot of paperwork and human workforce. The main goal of this online application is to make the business easy allowing the entire world to perform fast transactions like for the Owner to accomplish the assets information, tenants to fast get respectable deals followed by easy checkout and Administrator to manage properties and commercial details. Much such functionality has been implanted to search, book and travel helping the user. The main scope of the project is that the customer should be able to book the room or the house for stay online. To make sure that every user is different registration and authentication is required on the website. The use will be able to check which room is available with all the pricing. Different search criteria options will be available for the customer\u27s ease. The customer will be able to book, view, change and cancel the reservations at any given point in time. Secure access to confidential data (user’s details) should be provided. There will be a 24X7 availability of the application accessible over the Internet, which helps the users to open the website anytime. Most importantly the design will be better for better performance at peak time. To run this software the operating system should be Windows 7 and higher and the database will be created on the Microsoft SQL Server- 2012 or higher. This website will work on any browser; however, we would recommend using Internet Explorer as the browser

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

Monetary policy restriction and dividend behavior of Pakistani firms: an empirical analysis

Studies upon impact of macro variables on firm’s dividend policy are very limited and specifically rare in Pakistan perspective. Main purpose of this research paper is to observe impact of restricted monetary policy on dividend behavior of Pakistani firms. During restricted monetary policy, cost of external funds increases and firms prefer to utilize internal funds leading to reduction in dividend payout. Behaviour of 100 listed firms, selected purposefully, has been observed for the period from 2001 to 2009 by using Lintner’ modified model.. During the research period of nine years, monetary policy has been gone through both loose and tight phases. Proposed model is dynamic one as lagged dependent variable has been used as explanatory variable. Due to certain limitations with selection of monetary policy instrument, overall stance of State Bank of Pakistan (SBP) in its annual reports has been used as a dummy variable in the model. Results of all the three estimations reveal almost same results. First lagged dividend has been proved to be most deterministic factor of dividend policy followed by current earnings. Monetary policy and lagged dividends interactive variables provide mixed results. First interactive variable has negative coefficients in all three, fixed effect, random effects and GMM, models but with insignificant p values. Second monetary policy interactive variable has positive coefficients with significant values in random effects and GMM model. Firms seem to follow relatively stable dividend policies with lower adjustment factor. As model is dynamic, GMM estimation is preferred. Monetary policy has not been observed as significant determinant of dividend policy of Pakistani firms.Dividend payment, Monetary Policy

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