Assessment of electricity generation by wind power in nine costal sites in Malaysia

In this article, the wind power potential in Malaysia is examined. Hourly wind speed data for nine sites in Malaysia are used to optimally design wind power systems for remote housing electrification. These nine sites are Bintulu, Kota Kinabalu, Kuala Terengganu, Kuching, Kudat, Mersing, Sandakan, Tawau and Pulau Langkawi. The designed wind power systems are supposed to supply hourly load demand 6.13?kWh/day, 0.52?kW peak with 1% loss of load probability. The unit cost of the energy produced by each system is calculated and compared to the unit cost of the energy produced by a standalone photovoltaic (PV) power systems and a diesel generator power systems. The results show that the average unit cost of the energy produced by a wind power system in Malaysia is 1.6–7.29?USD/kWh while it is 0.35–0.5?USD/kWh and 0.27–0.30?USD/kWh for PV power system and diesel generator power system, respectively. Based on this, the use of wind power systems as standalone systems is not recommended for the selected sites.     

Feasibility study of wind energy utilization in Saudi Arabia

The wind map of Saudi Arabia indicates that the Kingdom is characterized by the existence of two vast windy regions along the Arabian Gulf and the Red Sea coastal areas. The mean annual wind speed in these two windy regions exceeds 9 knots (16.7 kmph) and ranges from about 14 to 22 kmph and 16 to 19 kmph over the Arabian Gulf and Red Sea coastal areas, respectively. The main characteristic features of the wind field of these regions are presented.Four sample sites are selected for possible installation of both small and large wind energy conversion systems. These sites are: Yenbo and Al-Wajh on the Red Sea coast, Dhahran on the Arabian Gulf coast and Quaisumah in the north east of the Kingdom. The manufacturers pre-mass production unit capital costs ($/kW) are used to estimate the cost of electricity produced, in cents/kW h. The estimated costs of electricity produced by WEC systems of various rated powers when installed at the four sites are presented. A further reduction in the manufacturers unit capital cost is still required to enable wind energy to compete with other conventional energy sources. For oil-producing countries, it may be a few decades before wind energy can become cost-competitive with other energy sources.     

A micro-DC power distribution system for a residential application energized by photovoltaic-wind/fuel cell hybrid energy systems

Renewable energy systems are of importance as being modular, nature-friendly and domestic. Among renewable energy systems, a great deal of research has been conducted especially on photovoltaic effect, wind energy and fuel cell in the recent years. In this study, a residential application of photovoltaic-wind/fuel cell hybrid energy system established at the Clean Energy House in Denizli, Turkey, has been investigated. The study is based on the distribution and consumption of Direct Current (DC) electrical energy which is produced by the hybrid system.     

Optimisation of solar and wind energy systems: a survey

In the last decade, the penetration of renewable energy sources (RESs) for energy generation has increased. Because of their several technical and environmental benefits, solar and wind energy systems are the major RESs that are being increasingly employed for different aims. In solar and wind energy systems, there are a variety of optimisation problems which are non-linear and non-convex in nature. Study of the literature shows that among the meta-heuristic techniques, genetic algorithm (GA) and particle swarm optimisation (PSO) are highly used to solve different optimisation problems of solar and wind energy systems. The main goal of this paper is to review different applications of GA and PSO in solar and wind energy systems. This review will enable the researchers to study the present status of different solar and wind optimisation problems and plan for future investigations.     

Optimal size and cost analysis of stand-alone hybrid wind/photovoltaic power-generation systems

Design of sustainable energy systems for the supply of electricity need correct selection and sizing to reduce investment costs. In this article, a new sizing methodology is developed for stand-alone hybrid wind/photovoltaic (PV) power systems, using multi-objective optimisation algorithms. Multi-objective particle swarm optimisation algorithm and non-dominated sorting genetic algorithm-II are selected related to their match with the nature of renewable energy sizing problem. A match evaluation method is developed based on renewable energy supply/demand match evaluation criteria, to size the proposed system in the lowest cost. As an example of application of this technique, six different wind turbines (WTs) and also six different PV modules have been considered. The sizing methodology determines a multi-objective design, obtaining the best solutions that the applied algorithm has found simultaneously considering three objectives: inequality coefficient, correlation coefficient, and annualised cost of system. The optimal number of WTs, PV modules, and batteries ensuring that the system total cost is minimised while guaranteeing a highly reliable source of load power is obtained. A management strategy has been designed to achieve higher electricity match rate. Based on the proposed technique, the algorithm developed for different cases, using the climatic condition data of the city Zabol, located in south-east of Iran. Additionally, a study of operating hours of diesel generator in optimal configuration is carried out.     

Performance of a combined passive/active solar house

The paper describes a residence designed and built to demonstrate that active and passive solar homes could be economically by conventional home builders. The systems were designed for simplicity and cost effectiveness. The home was built in 56 days with conventional building materials and built by labourers with no particular training in energy efficient building techniques. After one season of operation the energy use data shows impressive performance. The auxiliary fuel requirement for the heating season was only 0.035 MJ/m²°C-day (1.72 Btu/ft²°F-day).

Economically the home is equally impressive. An independent appraiser of the home valued the construction at US $67 500. In reality the home cost US $59 000 including contractor's overhead and profit. Subtracting from this the amount US $4000 for the Federal Solar Tax Credit results in an owner cost of US $55 000.

The project demonstrated that given proper consideration for design, construction techniques, and solar systems integration, a solar structure need not cost more than conventional construction.     

Inter connection of wind and photovoltaic systems: modelling,conversion and control

The importance and usage of renewable energy resources such as wind, photo voltaic systems, fuel cell, etc., has been increased exponentially day by day. This importance is mainly due to its abundant availability and low running cost. However, efficient energy harnessing from these sources is still a challenging task. Further, interconnection of these sources caters the needs of rural villages, which not only reduce the transmission losses but also improves the local controlling capability. Perhaps, interconnection of these intermittent resources increase the complexity in control. Hence, in this article, an exhaust review about the interconnection of Photo Voltaic (PV), Fuel and Wind energy system has been performed. In particular, it focusses on modelling, conversion and control of interconnected systems, which will help a researcher to pinpoint the problem of research and can investigate further to solve.     

Micro wind turbines in the UK domestic sector

The micro-scale wind turbine industry is expanding in the UK with institutional support and UK legislation encouraging the development of numerous companies with a profusion of design options. The application of micro wind turbines in urban environment is encouraged in the UK via a grant scheme which provides a proportion of the initial capital costs. This development is predicated on the assumption that micro wind turbines have the potential to reduce built environment CO₂ emissions. Current methods of estimating the wind speed are reported to over predict by approximately 2.0 m/s. The energy yields of a range of typical micro wind turbines (in the 0.4–2.5 kW size range) were estimated here using two wind speed datasets sited within 1 km of each other recorded with a temporal precision of 10 min. The annual energy yield of a 1.5 kW turbine was found to be 277 kWh and 2541 kWh for the two sites analysed indicating the problem with the current method of yield estimation. Between 33 and 55% of the electricity generated would be exported dependant on the dwelling's electrical demand. For the high yield site, the simple economic payback of this turbine was found to be 26.8 years i.e. beyond the likely life time of the turbine with CO₂ savings of 1093 kg CO₂. The research suggests that this technology does represent a possible route for reducing CO₂ emissions but this is unlikely to be realised unless an adequate method is found for more accurately predicting energy yield at a specific site.     

Applying a multi-objective optimization approach for Design of low-emission cost-effective dwellings

Modern buildings and their HVAC systems are required to be not only energy-efficient but also produce fewer economical and environmental impacts while adhering to an ever-increasing demand for better environment. Research shows that building regulations which depend mainly on building envelope requirements do not guarantee the best environmental and economical solutions. In the current study, a modified multi-objective optimization approach based on Genetic Algorithm is proposed and combined with IDA ICE (building performance simulation program). The combination is used to minimize the carbon dioxide equivalent (CO₂-eq) emissions and the investment cost for a two-storey house and its HVAC system. Heating/cooling energy source, heat recovery type, and six building envelope parameters are considered as design variables. The modified optimization approach performed efficiently with the three studied cases, which address different summer overheating levels, and a set of optimal combinations (Pareto front) was achieved for each case. It is concluded that: (1) compared with initial design, 32% less CO₂-eq emissions and 26% lower investment cost solution could be achieved, (2) the type of heating energy source has a marked influence on the optimal solutions, (3) the influence of the external wall, roof, and floor insulation thickness as well as the window U-value on the energy consumption and thermal comfort level can be reduced into an overall building U-value, (4) to avoid much of summer overheating, dwellings which have insufficient natural ventilation measures could require less insulation than the standard (inconsistent with energy saving requirements) and/or additional cost for shading option.     

Embodied energy and cost of building materials: correlation analysis

The US building sector consumes 48% of the nation’s annual energy as operating and embodied energy. Calculating embodied energy is difficult, complex and more resource-consuming than calculating operating energy due to a lack of complete, accurate and specific embodied energy data. One commonly used method to calculate embodied energy is input–output-based (IO) analysis, which utilizes economic data. The use of economic data indicates some relationship between embodied energy and cost. Some studies have investigated whether the embodied energy of a building can be predicted from its cost. These studies analyzed the relationship of the cost and embodied energy of a building and found a strong, positive correlation. However, when analyzed at the material level, the correlation weakened. This paper develops an improved input–output-based hybrid (IOH) model to calculate the complete, accurate and material-specific embodied energy of 21 commonly used building materials. After calculating and evaluating the embodied energy, the correlation of the embodied energy and cost of materials was analyzed. The results demonstrate a very strong and positive correlation between embodied energy and cost. In conclusion, more research may be required to predict embodied energy from cost data.     

Impact of daylight saving time on residential energy consumption and cost

This study is an evaluation of the effect of using or not using daylight saving time on a residential building's HVAC and lighting energy consumption. Daylight saving time is the practice of shifting clock time ahead by one hour. The well-verified and robust hour-by-hour simulation code DOE-2.1 E is used to predict a residence's annual energy consumption at 224 locations in the US. The quantities tracked are annual electrical energy use, electrical cost, natural gas quantity, natural gas cost and total energy cost. The house used in the study is an existing structure in Lawrence, KS, and its actual characteristics, operation schedules and utility bills are used in the preparation of the energy model. The results show that for this residence, which is somewhat typical of US houses, total energy consumption is just slightly increased on average when summer daylight saving time is used instead of standard time year-round. Other combinations of standard and daylight saving time are also examined.     

Feasibility study of wind farms: A case study for Izmir, Turkey

Wind is one of the world's fastest growing renewable energy sources. The rapid growth in wind power is a result of improvements accomplished in technology. This paper presents the technical and economical feasibility of wind farms. The method is applied to a potential wind farm site located in Izmir, Turkey. The site is considered on technical and economical parameters for the complete plant and its running costs. For technical consideration wind speed, prevailing wind direction, and temperature measurements are performed. For economical consideration, three different scenarios namely, autoproducer, autoproducer group, and independent power producer (IPP) cases, are investigated and compared with respect to net present value (NPV), internal rate of return (IRR), and pay back period (PBP) criteria. The study indicates the costs of generated energy by wind turbines with different characteristics as a function of the installed capacity. It is concluded that, the larger the installed capacity, the smaller the generating cost per kWh. The generating cost was calculated as low as 2.68 UScent/kWh for the IPP scenario. The profitability analysis also shows that, larger installed capacity with larger rated power wind turbines present higher IRR of the investment. The sensitivity analysis backs up the findings.     

Development of building energy asset rating using stock modelling in the USA

The US Building Energy Asset Score helps building stakeholders quickly gain insight into the efficiency of building systems (envelope, electrical and mechanical systems). A robust, easy-to-understand 10-point scoring system was developed to facilitate an unbiased comparison of similar building types across the country. The Asset Score does not rely on a database or specific building baselines to establish a rating. Rather, distributions of energy use intensity (EUI) for various building use types were constructed using Latin hypercube sampling and converted to a series of stepped linear scales to score buildings. A score is calculated based on the modelled source EUI after adjusting for climate. A web-based scoring tool, which incorporates an analytical engine and a simulation engine, was developed to standardize energy modelling and reduce implementation cost. This paper discusses the methodology used to perform several hundred thousand building simulation runs and develop the scoring scales.     

以风力驱动的热泵空调系统

本文介绍了风力制热以及风力驱动的压缩式、吸收式与机动车热泵空调系统,重点分析了风力制热,以风电、蓄电池和市电并联共同驱动的压缩式热泵空调装置和风力驱动的吸收式制冷(热泵)机组,分析了风力热泵的节能环保性能。     

Utilization of wind energy in space heating and cooling with hybrid HVAC systems and heat pumps

Approximately one-third of the primary energy resources are consumed in space heating, cooling, and air-conditioning with a very low exergetic efficiency. The depleting nature of primary energy resources, negative environmental impact of fossil fuels and low exergetic efficiencies obtained in conventional space heating and cooling are the main incentives for developing alternative heating, ventilating, and air-conditioning (HVAC) techniques which can employ low density and interrupted energy sources. In this respect, in spite of difficulties primarily encountered in coupling wind energy with conventional space heating and cooling equipment, wind energy seems to be an exciting alternative provided that synectic combinations are pursued and applied. In this paper, a new wind turbine coupled hybrid HVAC system is presented, which consists of an optimum combination of convective and radiant heating and cooling systems with in-space thermal energy storage. A design case for a single family home is presented. In this study a 6 kW(e) wind turbine drives a ground source heat pump (GSHP) which is coupled to a hybrid HVAC system to satisfy the thermal loads of a 100 m² home. In this example, sensible heating and cooling loads are satisfied by the high mass radiant floor which matches the daily peak demand and the available peak wind energy. Latent heating and cooling loads, along with ventilation requirements are satisfied by a forced-air system. Variable radiant and convective split type of control is implemented, and both systems are served by the same GSHP which also satisfies the domestic hot water (DHW) demand.     

A preliminary study of wind–solar hybrid systems potential in Jammu and Kashmir

ABSTRACT

This paper deals with the study of wind–solar hybrid systems in the region of Jammu and Kashmir. Due to scarcity of less renewable energy resources in the J&K region, National Institute of Wind Energy, Chennai had installed different wind monitoring stations to measure the wind data at different locations. The survey reveals that four districts (LEH, KARGIL, POONCH and REASI) are suitable for small wind–solar hybrid systems. BIDDA (REASI) and CHUSHUL (LEH) are the two sites for small wind farm development due to the highest wind speed (more than 7?m/s) and power density (more than 400?W/m²) at 100?m agl.     

城市中风力发电与建筑一体化设计

随着全球城市化程度的日益提高,城市所需能源急剧加大,当下对城市中风能利用的研究和应用具有重要的现实意义。通过介绍城市中风力发电与建筑一体化的设计方法,分析风力发电与建筑一体化设计的特点和存在的问题,提出三种一体化设计的方式：风机安装在屋顶上、风机安装在两座建筑物之间和风机安装在建筑物的空洞中。     

Optimization of refuse storage systems

A deterministic inventory computer model is developed and used in selecting the optimum sizes and number of on site refuse storage systems. The majority of these systems studied are either hauled containers or open waste dumps. The optimum sizes were selected by the computer program by comparing the cost of longer refuse storage times (larger storage containers or areas and lesser frequency of refuse pickup and collection vehicles) versus shorter refuse storage times (smaller storage containers or areas and greater frequency of refuse pick-up and collection vehicles).

Optimization of refuse storage systems, resulted in efficient scheduling of refuse collection vehicles and an annual refuse collection cost savings of about US $500000.     

Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems

With the current movement towards net zero energy buildings, many technologies are promoted with emphasis on their superior energy efficiency. The variable refrigerant flow (VRF) and ground source heat pump (GSHP) systems are probably the most competitive technologies among these. However, there are few studies reporting the energy efficiency of VRF systems compared with GSHP systems. In this article, a preliminary comparison of energy efficiency between the air-source VRF and GSHP systems is presented. The computer simulation results show that GSHP system is more energy efficient than the air-source VRF system for conditioning a small office building in two selected US climates. In general, GSHP system is more energy efficient than the air-source VRV system, especially when the building has significant heating loads. For buildings with less heating loads, the GSHP system could still perform better than the air-source VRF system in terms of energy efficiency, but the resulting energy savings may be marginal.     

Automated extraction and classification of thunderstorm and non-thunderstorm wind data for extreme-value analysis

Design wind loads are partly based on extreme value analyses of historical wind data, and limitations on the quantity and spatial resolution of wind data pose a significant challenge in such analyses. A promising source of recent wind speed and direction data is the automated surface observing system (ASOS), a network of about 1000 standardized US weather stations. To facilitate the use of ASOS data for structural engineering purposes, procedures and software are presented for (a) extraction of peak gust wind data and thunderstorm observations from archived ASOS reports, (b) classification of wind data as thunderstorm or non-thunderstorm to enable separate analyses, and (c) construction of data sets separated by specified minimum time intervals to ensure statistical independence. The procedures are illustrated using approximately 20-year datasets from three ASOS stations near New York City. It is shown that for these stations thunderstorm wind speeds dominate the extreme wind climate at long return periods. Also presented are estimates based on commingled data sets (i.e., sets containing, indiscriminately, both non-thunderstorm and thunderstorm wind speeds), which until now have been used almost exclusively for extreme wind speed estimates in the US. Analyses at additional stations will be needed to check whether these results are typical for locations with both thunderstorm and non-thunderstorm winds.