Green building in existing development: a review of current status, challenges, and implementation strategy

Green building development is on the rise with more new constructions receiving green building certification locally and globally. Starting with 247 papers in the first cycle searching of greening an existing building, this paper conducts a literature review over 30 relevant publications related to the effort towards greening the existing development from various countries especially in Malaysia, since three specific case studies on implementation of greening existing building were analyzed from this country. Regarding to the review on current development status, there occur several challenges of existing building standards from the regulatory that will slow the target achievement towards a sustainable plan besides the cost implication and project feasibility that resulting in most existing buildings do not embed green building elements. Therefore, retrofitting the existing structure might contribute to a positive, sustainable impact, including cost-saving, living comfortability, and environmental preservation. However, the decision-making on retrofitting action needs detailed analysis. This is especially in identifying expenditure on current building performance, potential cost benefits through lifecycle assessment and cost-benefit analysis. This paper presents three case studies of green retrofitting project in Malaysia and highlights twenty effective strategies towards successful retrofitting for sustainable development. According to the summative analysis of the strategies, the most important element to be addressed in retrofitting action towards a green building is thoroughly assessing the current performance and needs of the development to meet the sustainability impact. It is recommended for future researchers to conduct a survey on the details of the procedure from specific stakeholders with focus on regional-based existing building conditions

Current practice of early leak detection methods for underground storage tanks

This article aims to provide general review on current practice of leak detection methods of underground storage tanks (UST). Fuel (i.e. gasoline and diesel oil) leakage from UST can contaminate groundwater and drinking water with various hydrocarbon contaminants. These leaks create ponds of fuel that spill into the land and aquifers, polluting and seriously destroying habitats. Numerous efforts have been focused on the development of leak detection to the tanks. However, without the opportunity to conduct fault intensity calibration and estimate a product's lifetime, there is a lack of information provided to consider the condition of previous underlying leakage. As a result, it is too late whether the harm has already been done. There are methods of detection that have been studied for the past ten years. Many approaches have been practised to detect leakage. Specific sensing devices will combine with additional applications that analyse and interpret the data to detect storage tank leaks. Various methods will provide different results depending on the feature chosen. Some approaches will use machine learning to analyse the provided data and provide the best leak detection result. This paper will explore the best leak detection techniques to improve underground tanks' structural integrity. At the end, this paper will give some overview on current practice early detection methods on underground storage tanks for future research

Offshore structural reliability assessment by probabilistic procedures—a review

Offshore installations must be built to resist fatigue as well as extreme forces caused by severe environmental conditions. The structural reliability analysis is the popular practise to assess a variety of natural waves determined by the long‐term probability distribution of wave heights and corresponding periods on the site. In truth, however, these structures are subjected to arbitrary wave‐induced forces in the open ocean. Hence, it is much more reasonable to account for the changed loading characteristics by determining the probabilistic characteristics of the random loads and outcomes responses. The key challenges are uncertainties and the non‐linearity of Morison’s drag element, which results in non‐Gaussian loading and response distributions. This study would analyze advances achieved to date in a comprehensive probabilistic review of offshore fixed jacket-type platforms

Environmental impacts of utilization of ageing fixed offshore platform for ocean thermal energy conversion

Most Malaysian jacket platforms have outlived their design life. As these old platforms have outlived their design life, other alternatives must be considered. As several offshore oil and gas extraction installations approach the end of their operational life, many options such as decommissioning and the development of a new source of energy such as wind farms are introduced. The objective of this paper is to investigate the environmental impacts of utilising ageing fixed offshore platform as a source for Ocean Thermal Energy Conversion (OTEC). The environmental impact of utilising an ageing fixed offshore platform as an OTEC source is discussed. OTEC produces energy by taking advantage of temperature variations between the ocean surface water and the colder deep water through cold-water intake piping, which requires a seawater depth of 700 metres. The output of this study shows that OTEC is envisioned to preserve marine life, becoming a new and reliable source of energy, assist clean water production, and reduce the negative impact of climate change. OTEC platforms utilising ageing platforms may lead to 44 % of fish catch in the ocean, remove 13 GW of surface ocean heat for every GW of electricity production per year, generate 1.3105 tonnes of hydrogen per year for each GW of electricity generated. In addition, OTEC platforms can reduce approximately 5106 tonnes of carbon dioxide from the environment for 1 GW of electricity generated per year, and supply 2 million litres of water per day for a 1 MW platform. Since Malaysia's seawater profile allows for installing a fixed offshore platform as an OTEC power plant, Malaysia has many potentials to profit from the OTEC process

Efficient methods for the prediction of non-gaussian stochastic response of offshore structure

For offshore structural design, the load due to wind-generated random waves is usually the most important source of loading. A nonlinear wave analysis is recommended to represent a realistic ocean wave for an accurate prediction of extreme offshore structural response. However, the contribution of nonlinearity leads to a complex solution. A probabilistic analysis based on the Monte Carlo time simulation will be carried out due to its high level of accuracy. Unfortunately, the method is very time consuming. Hence, a new model need to be develop to improve its efficiency based on finite-memory nonlinear system. Details on the development of the model will be discussed and results from both methods will be compared. The most appropriate model can then be used with excellent efficiency and accuracy to determine the extreme offshore structural response. With that, the structure is towards optimization and lead to cost reduction

Prediction of offshore structural response extreme values by modified finite-memory nonlinear system modeling

Offshore structures are exposed to random wave loading in the ocean environment, and hence the probability distribution of the extreme values of their response to wave loading is of great value in the design of these structures. Due to nonlinearity of the drag component of Morison's wave loading and also due to intermittency of wave loading on members in the splash zone, the response is often non-Gaussian; therefore, simple techniques for derivation of the probability distribution of extreme responses are not available. However, it has recently been shown that the short-term response of an offshore structure exposed to Morison wave loading can be approximated by the response of an equivalent finite-memory nonlinear system (FMNS). Previous investigation has shown that the developed FMNS models perform better for high Hs values and that their performance for low Hs value is not particularly good. In this paper, MFMNS technique, a modified version of FMNS models is discussed. The improvement in MFMNS model is simply achieved by dividing the structure into two zones (Zones 1 and 2) so that the horizontal distance between the nodes in each zone is relatively small compared to the wavelengths. It is shown that MFMNS technique can be used to determine the short-term probability distribution of the extreme responses accurately with great efficiency

Efficient derivation of extreme offshore structural response exposed to random wave loads

The reliability of offshore structure is dominantly affected by the wind-generated random waves load. Hence, an appropriate technique is required in predicting the extreme response due to the dominant load. Monte Carlo (MC) time simulation is said to be the most accurate technique. However, such analysis leads to a large number of response records which is computationally demanding. Current finding shows that a modified finite-memory nonlinear system offered more efficient technique. Still, the accuracy is getting severe once negative current is considered. Hence, improved version of MFMNS technique is required by modelling the residue between the extreme values from MC and the approximate MFMNS techniques; known as the eMFMNS technique. In advanced, a comprehensive study on eMFMNS technique will be carried out involving a wide range of environmental conditions. From the investigation, it is proven that eMFMNS technique improved the accuracy in predicting extreme values compare to MFMNS technique

Integrated tidal marine turbine for power generation with coastal erosion breakwater

Malaysia experiences predictable tides year round. Areas with the greatest potential are Terengganu and Sarawak waters with average annual power generation between 2.8kW/m to 8.6kW/m. This condition gives excellent opportunity to explore power generation using tidal energy converters by utilization of stand-alone marine facilities such as breakwater with the tidal stream energy. The tidal energy converter is a device that converts the energy in a flow of fluid into mechanical energy by passing the stream through a system of fixed and moving fan like blades. The power output is dependent on its design characteristics, which covers the turbine specification and the met-ocean environmental condition. Hence, this paper focused on the conceptual design of the integrated marine turbine mounted on wave breakwater known as WABCORE. The proposed marine turbine was installed in the breakwater and the generated energy was estimated based on the performance analysis through Finite Element Analysis (FEA) and ANSYS Fluent Computational Fluid Dynamics (Fluent CFD) simulations. It was found that a maximum power output of 30 Watts could be generated by horizontal-axis axial-flow marine turbine with excellent venturi-effect of piping design that provided significant contribution on power generation