• Energy Research

Abstract Heat Pinch Analysis retrofit projects are typically performed by evaluating and maximising the heat recovery potentials within the individual process units. Once the potential improvements from the individual units have been assessed, the Total Site (TS) Heat Integration analysis is performed. Such approach may steer designers away from the promising retrofit opportunities and to lead towards suboptimal heat exchanger networks (HEN). This paper presents an effective retrofit framework for a TS system to determine the most cost-effective retrofit options and maximise the potential savings. Instead of performing the typical unit-wise process retrofit, the strategy is to determine the baseline total site consumption and benchmark targets, and to identify retrofit options from the TS context. This TS retrofit framework has been tested on a case study involving a petrochemical plant comprising of multiple process sections. The results of the analysis show that significant energy savings can be realised when both direct and indirect heat recovery retrofit options are evaluated. Further energy savings can be achieved via the Plus–Minus Principle that helps pinpoint the correct locations of heat surpluses and deficits and lead to the appropriate TS retrofit solution. As a conclusion, energy retrofit projects should be approached from the TS context, followed by the unit-wise retrofit (i.e., retrofit of the individual process sections).

A rice mill produces rice and a variety of by-products, including broken rice, rice bran, and rice husk. Rice husk, in particular, has been widely utilized as a source of fuel to generate heat and ...

The difference in electricity pricing based on the time of power use has led to load shifting from peak to off-peak hours in hybrid power systems (HPS). Apart from optimising electricity cost, shifting of load may also change the capacity of storage in the system. Power Pinch Analysis has been recently applied to guide load shifting aiming to minimise the cost of electricity, considering the peak and off-peak electricity pricing. This work extends the study by scrutinising the effects of peak/off-peak load shifting on the capacity of storage in HPS. Shifting heuristics are developed to ensure optimal storage size is achieved. Results show that the proposed load shifting strategy from peak to off-peak hours has successfully minimised the costs of both the storage system and the electricity bill.

There has been growing interests to reduce the environmental impact caused by greenhouse gas emissions from process plants through various energy conservation strategies. CO2 emissions are closely linked to energy generation, conversion, transmission and utilisation. Various studies on the design of energy-efficient processes, optimal mix of renewable energy and hybrid power system are driven to reduce reliance on fossil fuel as well as CO2 emissions reduction. This paper presents a systematic technique in the form of graphical visualisation tool for cost-effective CO2 emission reduction strategies in industry. The methodology is performed in four steps. The first step involves calculating the energy consumption of a process plant. This is followed by identification of potential strategies to reduce CO2 emissions using the CO2 management hierarchy as a guide. In the third step, the development of “Investment” versus “CO2 Reduction” (ICO2) plot is constructed to measure the optimal CO2 emission reductions achieved from the implementation of possible CO2 reduction strategies. The Systematic Hierarchical Approach for Resilient Process Screening (Wan Alwi and Manan in AIChE J 11:3981–3988, 2006) method is used in the fourth step via substitution or partial implementation of the various CO2 reduction options in order to meet the cost-effective emission reduction within the desired investment limit or payback period (PP). An illustrative case study on a palm oil refinery plant has been used to demonstrate the implementation of the method in reduction of CO2 emissions. The developed graphical tool provides an insight-based approach for systematic CO2 emission reduction in the palm oil refinery considering both heat and power energy sources. Result shows that 31.2 % reduction in CO2 emissions can be achieved with an investment of USD 38,212 and PP of 10 months based on the present energy prices in Malaysia.

Many countries have organised energy awards as an instrument to promote energy efficiency (EE), to contribute towards energy sustainability and to provide a mechanism for organisations to continuously search, benchmark and acknowledge initiatives and best practices in EE. To be effective, an award system must be tailored towards the needs, the level of readiness and the acceptance of a nation. This paper presents a framework for implementation of a national EE award in the context of Malaysia. The current energy scenario and energy issues relevant to Malaysia are first highlighted to establish the premise for organising a national energy award. Models and success stories of EE awards in other countries are discussed as possible benchmarks for implementation. The results of a survey conducted on various energy stakeholders in Malaysia confirmed the needs, readiness and acceptance for a national EE award. A framework for the implementation of a Malaysian EE award is proposed based on the survey conducted, and on various models of energy award implementation worldwide.

Abstract Electricity load distribution tends to vary throughout the day depending on the time of operations of equipment and processes and the ambient weather conditions. Load shifting from peak to off-peak hours changes the electricity load profile and allows users to control the peak electricity demand and optimise the electricity cost. Power Pinch Analysis (PoPA) has been used recently to guide load shifting aimed at reducing the electricity maximum demand. This work applies the PoPA to optimise the overall electricity cost for a hybrid power system by performing cost-effective load shifting that takes advantage of the peak and off-peak electricity tariffs. Two new heuristics for load shifting have been proposed in this work. The results show that the total outsourced electricity during the peak hours has been successfully distributed to the off-peak hours to minimise the electricity cost.

In assessing the greenness of a facility, a few green performance indicators and assessment tools such as the Building Research Establishment Environmental Assessment Method (BREEAM), the Leadership in Energy and Environmental Design (LEED), and Green Building Index have been developed. Although these tools can help promote green building designs and operations, they do not provide a quantitative measure of the overall impact of a facility on the environment. This is due to the fact that most of the current green rating assessment tools utilise the point-based rating system. Such system has several limitations. First, it can only provide a relative measure of the greenness of a system. Secondly, the points awarded may not be consistent as it can vary from one assessor to another. Finally, the available rating tools do not provide a single indicator of the greenness of a system as each green element of a system is evaluated separately rather than as a whole. This paper presents a new tool for assessing the greenness of a facility that overcomes the aforementioned limitations. The use of the stock market composite index as a tool to assess the stock market performance has been extended to the domain of facility management that includes industrial and commercial buildings. The composite index has been utilised as the basis to develop a Green Index to assess and manage an organisation’s level of greenness. The advantage of the composite index that could capture the movement of price within each stock and reflect it into a single composite index could be used in measuring and monitoring the impacts contributed by the individual green elements, on the environment. Results show that the formulation of the Green Index with weighting assignment using factor analysis would help organisations simultaneously optimise and improve their energy and water consumption, as well as waste generation. In addition, the Green Index graph provides facility managers with a graphical tool to visualise and gain insights on the performance trend of a facility.

Palm oil mill effluent (POME) is one of the biggest pollution sources due to its eutrophying nature and methane emitting treatment technology. Although biogas capture and utilisation have been widely encouraged to achieve greenhouse gas (GHG) mitigation in palm oil mills (POM), most Malaysian POMs still find it economically infeasible to invest in proper biogas facilities. Hence, POME elimination should be considered as one of the waste management options in synthesising palm oil processing pathway for profit enhancement and GHG mitigation. One of the solutions to achieve sustainability in palm oil industry is to integrate POM and palm oil refinery (POR) in terms of waste management, energy and resource. Therefore, it is desired to design an optimally integrated palm oil based-complex (POBC) which considers POME evaporation approach. The main objective of this study is to develop a model to aid POBC planning via synthesis of an integrated resource and utility network considering POME elimination with maximum profit. Based on the case study, maximum USD 36.65 x 106 is obtained for the optimal POBC design with POME elimination pathway selected. The optimum production rate for Refined, Bleached, Deodorised Palm Olein (RBDPOL) is 10.309 t/h which is boosted compared to the baseline study. 61 % less water demand is also achieved. The research output, the developed model and optimal network shall provide input to POM owners on optimal POME management and determine the economic feasibility of proposed POBC in Malaysia.

Utility targeting as well as optimal placement are among the key steps in the design of a cost-effective process utility system. Composite Curves, Grand Composite Curves (GCC) and Balanced Composite Curves are the established graphical tools for targeting and optimal placement of multiple utilities based on the Pinch Analysis technique. Although the composite graphical tools can provide valuable graphical insights and yield acceptable utility targets in terms of loads and levels, they could not pinpoint the exact heat recovery matches between process and utility streams. As a result, these composite graphical tools could not be used to perform heat allocation between the process and the individual utility streams, and for targeting the process-utility surface area targets. This paper presents an extended Stream Temperature versus Enthalpy Plot (STEP) method that is used to simultaneously target the multiple utilities and perform heat allocation between the utilities and the individual process streams. Due to the composite nature of the GCC, targeting involving variable-temperature utilities can yield inaccurate results. A case study has been used to demonstrate how this limitation can be overcome by using the extended STEP method.