Search results

Effective cooling is one of the challenges for photovoltaic thermal (PVT) systems to maintain the PV operating temperature. One of the best ways to enhance rate of heat transfer of the PVT system is using advanced working fluids such as nanofluids. The purpose of this research is to develop a numerical model for designing different form of thermal collector systems with different materials. It is concluded that PVT system operated by nanofluid is more effective than water-based PVT system.

In this research, a three-dimensional numerical model of PVT with new baffle-based thermal collector system has been developed and solved using finite element method-based COMSOL Multyphysics software. Water-based different nanofluids (Ag, Cu, Al, etc.), various solid volume fractions up to 3 per cent and variation of inlet temperature (20-40°C) have been applied to obtain high thermal efficiency of this system.

The numerical results show that increasing solid volume fraction increases the thermal performance of PVT system operated by nanofluids, and optimum solid concentration is 2 per cent. The thermal efficiency is enhanced approximately by 7.49, 7.08 and 4.97 per cent for PVT system operated by water/Ag, water/Cu and water/Al nanofluids, respectively, compared to water. The extracted thermal energy from the PVT system decreases by 53.13, 52.69, 42.37 and 38.99 W for water, water/Al, water/Cu and water/Ag nanofluids, respectively, due to each 1°C increase in inlet temperature. The heat transfer rate from heat exchanger to cooling fluid enhances by about 18.43, 27.45 and 31.37 per cent for the PVT system operated by water/Al, water/Cu, water/Ag, respectively, compared to water.

This study is original and is not being considered for publication elsewhere. This is also not currently under review with any other journal.

This paper aims to present a numerical study on the natural convection, which operates either as an evaporator or condenser unit of the heat pump system to pre-cool and pre-heat the ambient fresh air.

This study focuses on natural air cooling or heating within the air channel considering the double skin configuration. Particular focus is given to the analysis of airflow and the heat transfer processes in an air channel to cool or heat the ambient fresh air. In this study, the physical model consists of one wall, either heated uniformly or cooled uniformly, whereas the other wall is adiabatic.

The results show that the variation of both velocity and temperature is observed as the flow transition occurs at the evaporator or condenser wall. In either case, the temperature rises in the range of 6.3–8.4°C with an increase in mass flow rate from 0.07–0.08 kg/s in the photovoltaic thermal condenser part, while in the photovoltaic thermal evaporator part, the change in mass flow rate from 0.048–0.061 kg/s causes a decrease in temperature from 7.1–4.5°C.

The solar-assisted photovoltaic thermal heat pump system, in building façade having an air layer application, is feasible for pre-heating and pre-cooling the ambient fresh air and also reduces the energy needed to treat the fresh air.

The influence of condensing and evaporating temperature under natural convection mode in double skin conformation is considered for pre-heating and pre-cooling of ambient fresh air.

This study investigated the impact of the virtualization requirements of the learning process on students' satisfaction and their intention to continue using online learning.

A research model was developed using the process virtualization theory (PVT); it was validated empirically using data obtained from an online questionnaire-based survey of 489 undergraduate students.

The main results support the role of representation for sensory requirements, sensory requirements, reach, representation for relationship requirements and relationship requirements on shaping students' satisfaction, which all also have a significant influence on students' intention to continue using online learning. Relevance factors are responsible for 61.6% of the variance in students' satisfaction and 83.6% of the variance in their intention to continue using online learning. However, neither the synchronism requirements nor the identification and control requirements had a significant effect on students' satisfaction or on their intention to continue using online learning.

The present research focused on PVT in an online learning context; consequently, a new set of factors that influenced students' satisfaction with and intentions to continue using online learning was empirically tested for the first time. This research contributes to the literature on information systems because it advances the generalizability and applicability of the PVT in a new context and new cultural setting. Moreover, the research apprises researchers and practitioners of new factors, which should be understood and fulfilled to make virtual learning equivalent to the face-to-face learning experience.

This study aim to use the finite volume method to solve differential equations related to three-dimensional simulation of a solar collector. Modeling is done using ANSYS-fluent software program. The investigation is done for a photovoltaic (PV) solar cell, with the dimension of 394 × 84 mm², which is the aluminum type and receives the constant heat flux of 800 W.m⁻². Water is also used as the working fluid, and the Reynolds number is 500.

In the present study, the effect of fluid flow path on the thermal, electrical and fluid flow characteristics of a PV thermal (PVT) collector is investigated. Three alternatives for flow paths, namely, direct, curved and spiral for coolant flow, are considered, and a numerical model to simulate the system performance is developed.

The results show that the highest efficiency is achieved by the solar cell with a curved fluid flow path. Additionally, it is found that the curved path’s efficiency is 0.8% and 0.5% higher than that of direct and spiral paths, respectively. Moreover, the highest pressure drop occurs in the curved microchannel route, with around 260 kPa, which is 2% and 5% more than the pressure drop of spiral and direct.

To the best of the authors’ knowledge, there has been no study that investigates numerically heat transfer, fluid flow and electrical performance of a PV solar thermal cell, simultaneously. Moreover, the effect of the microchannel routes which are considered for water flow has not been considered by researchers so far. Taking all the mentioned points into account, in this study, numerical analysis on the effect of different microchannel paths on the performance of a PVT solar collector is carried. The investigation is conducted for the Reynolds number of 500.

The roofs of houses located at middle latitudes receive significant solar radiation useful to supply their own energy demands and to feed back into the urban electricity network. However, solar panels should be properly integrated into roofs. This study analyzed roof geometry and integrated solar performance of Photovoltaic, thermal-photovoltaic, and hybrid solar collection technologies on dwelling cases selected from a sample of recent housing developments in Concepción, Chile. Hour-by-hour energy generation estimates and comparisons with demand levels were calculated for representative days during seasons of maximum, minimum as well as mid-season. These estimates took into account the roof tilt and orientation effects also. Trnsys@ software was used to determine electricity supply and F-Chart tool for thermal energy supply. The results show five times more panels can be placed on the largest and most regular shaped roof sections than on those with the smallest and most irregular shapes. The house model with the largest roof section can provide up to six times more energy than the model with the smallest second roof section in different seasons and systems. This paper thus provides new findings on the performance of solar technologies when related to home energy demands and roof geometry.

This case study aims to be taught at an MBA level. Students who are majoring in the supply chain would benefit the most from this case study. This case study has elements of logistics management, supply chain management, supply chain strategies, warehouse and logistics and responsible supply chain. The learning outcome of this case study could be seen if the students identify the gaps in the real market setting and come up with strategies that would connect and/or fill the areas missing. Teaching objective 1: students should be able to identify unstable demand scenarios and learn how demand collaboration could be implemented in that setting. Teaching objective 2: students should identify how a transparent and interconnected supply chain, both upstream and downstream, can be created. Teaching objective 3: students should be able to understand the role of a responsible supply chain and to define the role and responsibility of each party. Teaching objective 4: students should be able to learn the dynamics of safety stocks, reorder points and incorporate that in warehouse management decisions.

Based in Lahore, Pakistan, Total Technologies (Pvt.) Ltd is a company that supplies medical equipment and provides solutions in the health-care industry. This case explores the supply chain issues faced by Tallat Mehmood, who is the Managing Director of the company, during the third wave of the COVID-19 pandemic in April 2021. Oxygen cylinders have become the need of the hour as more and more patients need oxygen. The supply of medical gases across Pakistan has become a logistical issue, causing hospital reserves to be drained without timely replenishment. Increasing the number of beds in hospitals, with limited oxygen outlets, has increased the demand for oxygen cylinders. Operating under unstable demand and not being able to meet it has caused Tallat to realize that the company is out of its comfort zone and is not responding well to the environment. The company needs to redesign the supply chain as well as collaborate with the supplier and buyer to provide better levels of service.

Masters level supply chain courses.

Teaching Notes are available for educators only.

CSS 9: Operations and logistics.

This paper aims to develop a selective energy optimisation of the photovoltaic–thermal (PV/T) system performance. The PV cell inside the PV/T system could be periodically manipulated to produce domestic hot water without applying an external power supply.

A numerical simulation model of the proposed PV/T model was developed in MATLAB/Simulink to analyse the selective energy optimisation of the model. The extrinsic cell resistance (R_se) is adjusted to control the ratio of thermal to the electrical energy, generated from the PV cell inside the PV/T system. Therefore, the internal heat of the PV cell inside the PV/T system is periodically used as a thermal element to produce electrical power and hot water.

The optimisation of PV/T energy shows that the electrical power efficiency can increase by 11.6% when R_se was 0 Ω, and the 200 L water tank temperature increased by 22ºC when R_se was 50 Ω.

This study showed that the use of the PV cell could be extended to domestic hot water and space heating, and not only for electricity.

This paper aims to provide an opportunity to study organization buying behavior, specifically buying and selling in the B2B context. The case demonstrates the need to understand the expectations of the buyer’s decision-making unit and the challenges involved in acquiring and retaining customers based on the articulated value proposition of the product. The case also provides an opportunity to explore the critical issues related to an organization’s buying process, while emphasizing on the importance of customer relationship management and the challenges involved in sales conversion.

The case is a filed-based study that aims to provide insight on differences between buying and selling in B2B & B2C and an understanding on customer value proposition in B2B buying context.

The case provides a comprehensive overview on the key role of decision-making units and decision-making process in B2B context.

This is an India-specific field-based case study on B2B selling situation. The case provides a framework on salesperson B2B selling approach, techniques and skills in view of the changing business selling environment in the age of technologically advanced digital world.

The environmental impact of energy supply is growing which has a significant impact on regional and global environmental issues. As a solution for this, both developed and developing nations paying attention to convert their energy productivity by using renewable energy like wind and solar energy. Sri Lankan government also aims to obtain the full amount of electricity required from local renewable sources by the year 2050 under the project called “sooryabala sangramaya” (the battle for solar energy). Currently, Sri Lanka’s power generation sector is heavily dependent on imported fuels, such as petroleum and coal, resulting in growing detrimental impacts on the country’s sustainable socioeconomic development. With the growing market of solar photovoltaic (PV) technology, Sri Lanka is turning its attention towards generating the total amount of electricity required from solar power by promoting the installation of arrays of PV panels on the rooftops of households, religious places, hotels, commercial establishments and industries. It also aims to deploy solar PV for sustainable rural development, mainly focused on uplifting people living in remote areas in the country. This chapter discusses how Sri Lanka has initiated a rooftop solar PV adoption program to lessen imported fuels’ socioeconomic and environmental impacts. Moreover, this case demonstrates that the adoption of rooftop solar PV brings many socioeconomic benefits to its consumers.