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This paper aims to investigate the exergetic sustainability index (SI) of a dual-fluid PV/T type solar collector that integrates both air and water into the same solar collector. The contribution of the exergy efficiency of each of the dual fluid PV/T collector's components to the overall sustainability of the whole system was analysed. A theoretical approach based on an experimentally validated numerical model was employed. The results show that the SI of the PV component of the dual fluid PV/T system is in general higher than the solar thermal component by approximately 9% since it is higher in quality. When evaluated under three different climatic conditions, the contribution of the thermal component as a cooling medium to the PV is only prominent in hot climates with SI higher by 4% compared to the stand-alone PV system. For the cool and cold temperate climates, the difference is less than 0.1%.

Wind energy is recognised as a potential source for free, clean and inexhaustible energy. Therefore, the diffusion of wind energy technology in the power sector has been growing steadily in the past few decades due to the rising concern in global energy issues. Wind power machines, or commonly known as wind turbines, are still further developing over the years to increase its performance in term of efficiency, cost-effectiveness and reliability in wind energy and wind power application. However, there are challenges in the recent developments and technology trends particularly on introducing Nano technology on wind turbine blade design, offshore deployment and operation. This chapter provides fundamental knowledge of wind turbines operation and the implementation of Nano technology on the design aspects of turbine blades with some factors that could affect the performance of wind turbines. Furthermore, the environmental issues that are affecting the performance of wind turbines are also discussed. The details of this chapter cover the challenges of wind turbine design, followed by the principle of wind turbine design and the environmental issues that affect the aerodynamic efficiency of wind turbines.

This paper introduces the Eco-Greenergy™ hybrid wind-solar photovoltaic energy generation system and its applications. The system is an integration of the novel omni-direction-guide-vane (ODGV) with a vertical axis wind turbine (VAWT). The ODGV is designed to surround the VAWT for wind power augmentation by creating a venturi effect to increase the on-coming wind speed before it interacts with the turbine blades. In wind tunnel tests, the ODGV improves the power output of the VAWT by 3.48 times compared with a bare VAWT at its peak torque. Furthermore, the rotor rotational speed of the wind turbine increased by 182% at 6 m/s of wind speed. A solar PV panel can be mounted on the top surface of the ODGV for solar energy generation. Estimation on wind-solar energy output shows that the system can generate a total of 572.8 kWh of energy per year. By comparison, the ODGV increases the annual wind energy output by 438%. The green energy generated from the hybrid system can be used to power LED lights or other appliances (e.g., CCTV camera).

This paper explained the theoretical framework of smart energy system worked for smart home building for producing the green energy. In this paper, we explained how we build smart home from the hybridization of solar panel and wind turbine. This project is initiate in rural area at Kampung Tanjung Resang, Mersing Malaysia. We explained the overall function and the theoretical framework of this energy management and its impact towards social activities. The implementation of this smart energy is hope to increase the awareness of people in rural area. Smart energy management also will benefit the area which is much cleaner and energy saving.

Autoclaved aerated concrete (AAC) has become more attractive in construction due to its excellent environmentally friendly in building construction. Due to its increasing applications, the AAC wastes become abundance in construction site. Apparently, recycling the concrete waste powder to a wall concrete, particularly an autoclaved aerated concrete (AAC) was not frequently practiced in construction and moreover no study has been carried out yet. AAC is relatively lightweight, having lower thermal conductivity, higher heat resistance, lower shrinkage, and faster in construction process compared to normal concrete. AAC concrete is a combination of silica sand, cement, lime, water and an expansion agent. To improve its physical and mechanical properties and to reduce its production cost, tremendous innovation which used waste materials as partial replacement of AAC materials have been done. From these innovations, the use of recycled AAC as a partial replacement for wall concrete has not been carried out yet. This paper is intended to classify the literatures on the innovations that have been done on replacement in AAC materials to enhance its physical and mechanical properties and thermal performance. The physical properties in terms of its microstructure and the mechanical properties such as density, compressive strength, water absorption are presented to classify the investigation that has been done in such innovations. Apart of that, the discussion on innovations to improve its thermal performance also presented. To conclude, up to now, there is no attempt on using the recycled AAC waste powder as a partial replacement in AAC as a wall concrete is reported.

An assembly of two vertical axis wind turbines (VAWTs) and an enclosure is installed above a cooling tower to harness the discharged wind for electricity generation. The enclosure consists of guide-vanes and diffuser-plates, is used to enhance the rotational speed of the turbines for power augmentation. The angle of the guide-vanes is optimized to ensure the oncoming wind stream impinges the rotor blades of the turbine at an optimum angle. The diffuser-plates are tilted at an optimum angle to increase the discharged airflow rate. The performance of the system is tested in the laboratory followed by a field test on an actual size cooling tower. The VAWT performance is increased in the range of 7–8% with the integration of enclosure. There is no significant difference in the current consumption of the fan motor between the bare cooling tower and the one with installed VAWTs. With the presence of this system, approximately 17.5 GW h/year is expected to be recovered from 3000 units of cooling towers at commercial areas, assuming the cooling tower is driven by a 7.5 kW fan motor and operates 16 h/day. This amount of recovered energy can also be translated into 13% reduction in CO2 emission.

The exhaust air energy recovery wind turbine generator is an on-site clean energy generator that utilizes the advantages of discharged air which is strong, consistent and predictable. Two vertical axis wind turbines (VAWTs) in cross-wind orientation which are integrated with an enclosure are installed above a cooling tower to harness the discharged wind for electricity generation. It is mounted at a specific distance and position above the cooling tower outlet. The enclosure (consisting of several guide-vanes and diffuser-plates) acts as a wind power-augmentation device to improve the performance of the VAWTs. The guide-vanes are placed in between the discharged air outlet and the wind turbine. They are designed to guide the on-coming wind stream to an optimum flow angle before it interacts with the rotor blades. The diffuser-plates are built extended from the outlet duct of the exhaust air system. They are tilted at an optimum angle to draw more wind and accelerate the discharged air flow. A particular concern related to public safety which may be due to blade failure is minimized since the VAWTs are contained inside the enclosure. The performance of the VAWTs and its effects on the cooling tower's air intake speed and current consumption of the power-driven fan were investigated. A laboratory test was conducted to evaluate the effectiveness of the energy recovery wind turbine (5-bladed H-rotor with 0.3 m diameter) generator on a cooling tower model. The results showed a reduction in the power consumption of the fan motor for cooling tower with energy recovery turbine compared to the normal cooling tower while the intake air speed increased. Meanwhile, the VAWT's performance was improved by a 7% increase in rotational speed and 41% reduction in response time (time needed for the turbine to reach maximum rotational speed) with the integration of the enclosure. This system can be used as a supplementary power for building lighting or fed into electricity grid for energy demand in urban building. The energy output is predictable and consistent, allowing simpler design of the downstream system. The fact that there is an abundance of cooling tower applications and unnatural exhaust air resources globally causes this to have great market potential.

This paper presents an idea on generating green energy by extracting discharged wind energy from a cooling tower. Two vertical axis wind turbines (VAWTs) integrated with a wind power-augmentation device are installed above a cooling tower to harness unnatural wind for electricity generation. The wind power-augmentation device is built with several guide-vanes and diffuser-plates to improve the performance of the VAWTs. Guide-vanes are designed to create a venturi effect and guide the on-coming wind stream to an optimum flow angle which is matched to the optimum angle of attack of the VAWTs. Diffuser-plates are tilted at an optimum angle to draw more wind and accelerate the discharged airflow. From the laboratory test, the VAWTs performance was increased by 7 – 8 % when guide-vanes and diffuser-plates are installed at their optimum angle. The correct matching of VAWTs for this system is expected to generate electricity at their rated power constantly when the cooling tower is in operation. This system can contribute to the reduction of greenhouse gases emission and conservation of the environment for a healthier life since fossil fuel consumption for energy generation is reduced as well as efficient use of energy.

Recently, there are small wind turbine developments which are suitable for urban and suburban application. However, the efficiency of the wind turbine is the main concern for all researchers due to the uncertainty of wind speed and wind direction in urban area. In this paper, a new power augmented shroud integrated with vertical axis wind turbine (VAWT) is introduced. This power augmented shroud is able to improve the performance of the VAWT significantly by increasing the wind speed. It also channels the flow to better angle of attack for the VAWT and reduces the negative torque of the wind turbine. Hence, it improves the self-starting behaviour of the VAWT, and increases the coefficient of power. The numerical method is used to simulate the wind flow for the power augmented shroud with a single bladed NACA 0015 airfoil VAWT by commercial computational fluid dynamic (CFD) software, ANSYS FLUENT 14.0. In this 2D simulation, the shear stress transport (SST) k-ω turbulence model with the sliding mesh method was used with the tip speed ratio of 5.1 for the wind turbine. The result was verified by re-simulating the experiment published by the Sandia National Laboratories. The simulation result shows that the new design of power augmented shroud is able to increase the coefficient of power significant for the VAWT which is about 147.1% compared to the bare VAWT. Therefore, for urban area application, this power augmented shroud can improve the low efficiency problem for the VAWT.

An innovative idea on extracting clean energy from man-made wind resources with micro wind turbine system for power generation is introduced in this paper. This system generates on-site clean energy using a micro wind generation system. A vertical axis wind turbine (VAWT) with an enclosure is mounted above a cooling tower’s exhaust fan to harness the wind energy for producing electricity. The VAWT is positioned at a specific position at the cooling tower outlet to avoid a negative impact on the performance of the cooling tower. The enclosure can act as a safety cover and also enhance the performance of the VAWT. It is designed with several guide-vanes positioned at the up-stream side of the wind turbine to create a venturi effect and guide the wind before it interacts with the turbine blades. Moreover, the enclosure design is comprised of diffuser-plates that can draw more wind and accelerate the flow. Laboratory test conducted on a scaled model shows no measurable difference in the air intake speed and current consumption of the power-driven fan when the turbine was spinning above the cooling tower. Field test on an actual induced-draft cooling tower shows no significant difference on the outlet air speed of the cooling tower. A small difference was observed on the power consumption by the fan motor which is 0.39% higher with the presence of the VAWT. This system is retrofit-able to existing cooling towers and has very high market potential due to abundant cooling towers and other unnatural exhaust air resources globally.

This paper investigates a technology-driven solution to supply a portion of energy demand in future green cities. An idea on harnessing unnatural wind resources for electricity is presented. Two vertical axis wind turbines with an enclosure are mounted above a cooling tower to recover part of the energy from the exhaust air. Guide-vanes are designed to create a venturi effect and guide the wind before it interacts with the turbine blades. Diffuser-plates help to draw more wind and accelerate the exhaust airflow. Safety concerns that may result from blade failure are minimized by the design of the enclosure. From the laboratory test and field test results, there is no significant difference in the current consumption of the fan motor with the installation of the wind turbines. The integration of the enclosure has shown an improvement on the turbine’s rotational speed which is 30.4% higher. The electricity generated from this system can be fed into the electricity grid. For 3000 units of cooling tower (2 m outlet diameter powered by a 7.5 kW fan motor and operated for 16 hours/day), 13% of the energy to power the fan motor is expected to be recovered from this system which equals 17.5 GWh/year.

A shrouded wind turbine system has a number of potential advantages over the conventional wind turbine. A novel power-augmentation-guide-vane (PAGV) that surrounds a Sistan wind turbine was designed to improve the wind rotor performance by increasing the on-coming wind speed and guiding it to an optimum flow angle before it interacts with the rotor blades. The integration of the PAGV into the 3-in-1 wind, solar and rain water harvester on high-rise buildings has been illustrated. A particular concern related to public safety is minimized when the wind turbine is contained inside the PAGV and noise pollution can be reduced due to the enclosure. Besides, the design of the PAGV that blends into the building architecture can be aesthetic as well. Moreover, a mesh can be mounted around the PAGV to prevent the bird-strike problem. From the wind tunnel testing measurements where the wind turbine is under free-running condition (only rotor inertia and bearing friction were applied), the wind rotor rotational speed (with the PAGV) was increased by 75.16%. Meanwhile, a computational fluid dynamics (CFD) simulation shows that the rotor torque was increased by 2.88 times with the introduction of the PAGV. Through a semi-empirical method, the power output increment of the rotor with the PAGV was 5.8 times at the wind speed of 3 m/s. Also, the flow vector visualization (CFD) shows that a larger area of upstream flow was induced through the rotor with the PAGV.

Recovering energy from exhaust air systems of building cooling towers is an innovative idea. A specific wind turbine generator was designed in order to achieve this goal. This device consists of two Giromill vertical axis wind turbines (VAWT) combined with four guide vanes and two diffuser plates. It was clear from previous literatures that no comprehensive flow behavior study had been carried out on this innovative device. Therefore, the working principle of this design was simulated using the Analysis System (ANSYS) Fluent computational fluid dynamics (CFD) package and the results were compared to experimental ones. It was perceived from the results that by introducing the diffusers and then the guide vanes, the overall power output of the wind turbine was improved by approximately 5% and 34%, respectively, compared to using VAWT alone. In the case of the diffusers, the optimum angle was found to be 7°, while for guide vanes A and B, it was 70° and 60° respectively. These results were in good agreement with experimental results obtained in the previous experimental study. Overall, it can be concluded that exhaust air recovery turbines are a promising form of green technology.

An innovative 3-in-1 wind–solar hybrid renewable energy and rain water harvester is designed for urban high rise application. A novel power-augmentation-guide-vane (PAGV) that surrounds the Sistan rotor vertical axis wind turbine (VAWT) is introduced to guide and increase the speed of the high altitude free-stream wind for optimum wind energy extraction. The system was also designed to provide optimum surface area and orientation for solar power generation. On the top surface of the PAGV, rain water can be collected, thereby reducing the electrical power required to pump water to the upper levels of the high rise building. To minimize the visual impact, the outer design of the PAGV can be blended into the building architecture. The system is also designed to eliminate the bird-strike problem and the concern on safety, and reduce the vibration. Wind tunnel testing on the scaled down prototype shows that the PAGV improved the starting behavior and increased the rotational speed of the Sistan rotor VAWT by 73.2% at the wind speed of 3 m/s. According to the present study, with the 30 m diameter and 12 m high PAGV integrated system, the estimated annual energy generated and savings is 160 MW h.

A novel shrouded wind-solar hybrid renewable energy and rain water harvester with an omni-directional-guide-vane (ODGV) for urban high-rise application is introduced. The ODGV surrounds the vertical axis wind turbine (VAWT) and enhances the VAWT performance by increasing the on-coming wind speed and guiding it to an optimum flow angle before it interacts with the rotor blades. An ODGV scaled model was built and tested in the laboratory. The experimental results show that the rotational speed of the VAWT increases by about 2 times. Simulations show that the installation of the ODGV increases the torque output of a single-bladed VAWT by 206% for tip speed ratio of 0.4. The result also reveals that higher positive torque can be achieved when the blade tangential force at all radial positions is optimized. In conclusion, the ODGV improves the power output of a VAWT and this integrated design promotes the installation of wind energy systems in urban areas.

Building Integrated Photovoltaic thermal solar collector (BIPVT) with Spiral flow absorber design is a collector not only used to generate electricity and thermal energy simultaneously but also can be integrated with the roof. Due to it characteristic as a roof, the collector is exposed to the direct sunlight resulting from a higher temperature on it surfaces. The temperature increased will simultaneously decrease it efficiency. An experiment has been conducted outdoor at Universiti Kebangsaan Malaysia to examine and evaluate the efficiency of the collector. Data for the experiment has been collected and gathered from 08:00 to 17:00 respectively. Results from the experiment recorded the best total efficiency of 65.10% (53.64% thermal efficiency and 11.46% electrical efficiency from the PV panel) at mass flow rate of 0.041kg/s and solar radiation of 1148W/m2. The effect of mass flow rates on open circuit voltage (Voc) and the modules short circuit current (Isc) are also presented.

A novel cross axis wind turbine (CAWT) which comprises of a cross axis blades arrangement was presented and investigated experimentally. The CAWT is a new type of wind turbine that extracts wind energy from airflow coming from the horizontal and vertical directions. The wind turbine consists of three vertical blades and six horizontal blades arranged in a cross axis orientation. Hubs in the middle of the CAWT link the horizontal and vertical blades through connectors to form the CAWT. The study used a 45° deflector to guide the oncoming airflow upward (vertical wind direction). The results from the study showed that the CAWT produced significant improvements in power output and rotational speed performance compared to a conventional straight-bladed vertical axis wind turbine (VAWT).

The integration of a vertical axis wind turbine (VAWT) with the novel omni-directional shroud is proposed. It consists of the upper wall, lower wall and an array of 5 guide-vanes. Wind from all directions is collected radially from a larger area and the geometry of omni-directional shroud creates a venturi effect to increase the wind speed before entering the wind turbine. Guide-vanes aid to channel wind to better angles-of-attack of the turbine blades. Hence, self-starting behavior of the VAWT and the coefficient of power improve. The system was investigated numerically by simulating the wind flow over the omni-directional shroud with a single bladed NACA 0015 airfoil VAWT. In this 2D simulation, the shear stress transport (SST) k-Ȧ turbulence model with the sliding mesh method was used with the tip speed ratio of 5.1 for the wind turbine. The result was verified by re-simulating the experiment published by the Sandia National Laboratories. The result shows that the torque coefficient of the VAWT was increased up to 287% as compared to the bare VAWT. This system improves the performance of the VAWT and it has a great potential to be sited in urban areas for onsite and grid-connected power generation. University of Malaya for the research grant allocated to further develop this design under High Impact Research Grant (D000022-16001). Sincere gratitude is also dedicated to the Malaysian Ministry of Higher Education (MOHE) for Fundamental Research Grant Scheme (FP053-2013B) assigned for this project. Scopus

A novel omni-direction-guide-vane (ODGV) that surrounds a vertical axis wind turbine (VAWT) is designed to improve the wind turbine performance by increasing the oncoming wind speed and guiding the wind-stream through optimum flow angles before impinging onto the turbine blades. Wind tunnel testing was performed to measure the performance of a 5-bladed H-rotor wind turbine with Wortmann FX63-137 airfoil blades, with and without the integration of the ODGV. The test was conducted using a scaled model turbine which was constructed to simulate the VAWT enclosed by the ODGV on a building. The diameter and height of the ODGV are 2 times larger than the VAWT's. Torque, rotational speed and power measurements were performed by using torque transducer with hysteresis brake applied to the rotor shaft. The VAWT shows an improvement on its self-starting behavior where the cut-in speed reduced to 4 m/s with the ODGV (7.35 m/s without the ODGV). Since the VAWT is able to self-start at lower wind speed, the working hour of the wind turbine would increase. At the wind speed of 6 m/s and free-running condition (only rotor inertia and bearing friction were applied), the ODGV helps to increase the rotor RPM by 182%. At the same wind speed (6 m/s), the ODGV helps to increase the power output by 3.48 times at peak torque. With this innovative design, the size of VAWT can be reduced for a given power output and should generate interest in the market, even for regions with weaker winds.

An exhaust air energy recovery turbine generator is designed to recover part of the energy in the discharged air from an exhaust air system. The design is a combination of H-rotor vertical axis wind turbines (installed in cross-wind position), guide-vanes and a diffuser. Its working principle was tested on a scaled model of cooling tower and simulated in a computational fluid dynamic (CFD) package. From the guide-vanes study, optimum guide-vanes arrangement is 100, 70 and 90. The system with optimized guide-vanes arrangement produced the highest torque coefficient compared to the other configurations. The average torque coefficient of the system was increased by 24.3% with the introduction of diffuser and guide-vanes at optimized angles, i.e. from 0.029 to 0.036. From the graph of the torque coefficient versus azimuth angle, the overall positive torque zone was increased with the introduction of the guide-vanes with optimum configuration. The exhaust air energy recovery turbine generator can be another green technology that recovers waste energy from the discharged wind of an exhaust air system for urban areas.