Marta Vivar

An experimental investigation on diesel and low heat rejection engines with dual biodiesel blends.

In this article, the effects of thermal barrier coated combustion chamber on the single cylinder direct injection diesel engine with dual biodiesel (combination of pongamia pinnata oil and neem oil) are experimentally investigated. The piston surface and cylinder head of the diesel engine are coated with Aluminium Titanate. The two biodiesels are mixed with diesel in various proportions and their performances are examined by using both base engine and low heat rejection engine. Specific fuel consumption of coated engine (CE) with diesel--pongamia pinnata--neem 1 (DPN 1) fuel (mixture of diesel 75%, pongamia pinnata oil ethyl esters 22.5%, and neem oil ethyl esters 2.5% by volume) is 13.9% lower than the baseline engine. The brake thermal efficiency of DPN 1 CE is 11.9% higher than baseline engine. Smoke opacity and hydrocarbon emission from CE are lower than the baseline engine. The DPN 1 CE emits 16.6% lower smoke than the diesel fuel in baseline engine. However, nitrogen oxides and carbon dioxide emission are increased in the CE.

Performance and emission characteristics of double biodiesel blends with diesel

Recent research on biodiesel focused on performance of single biodiesel and its blends with diesel. The present work aims to investigate the possibilities of the application of mixtures of two biodiesel and its blends with diesel as a fuel for diesel engines. The combinations of Pongamia pinnata biodiesel, Mustard oil biodiesel along with diesel (PMD) and combinations of Cotton seed biodiesel, Pongamia pinnata biodiesel along with diesel (CPD) are taken for the experimental analysis. Experiments are conducted using a single cylinder direct-injection diesel engine with different loads at rated 3000 rpm. The engine characteristics of the two sets of double biodiesel blends are compared. For the maximum load, the value of Specific Fuel consumption and thermal efficiency of CPD-1 blend (10:10:80) is close to the diesel values. CPD blends give better engine characteristics than PMD blends. The blends of CPD are suitable alternative fuel for diesel in stationary/agricultural diesel engines.

A 20-sun hybrid PV-Thermal linear micro-concentrator system for urban rooftop applications

A unique, linear, low-concentration, hybrid ‘micro-concentrator’ (MCT) system concept has been developed specifically for urban rooftop environments. The light-weight, low-profile form factor satisfies aesthetic demands for general rooftop solar technologies, and is a marked departure from conventional linear concentrator systems. Valuable thermal energy, normally of nuisance value only, and usually wasted by conventional CPV, is extracted via a heat transfer fluid. The recovered thermal energy can be used for applications ranging from domestic hot water through to space heating, ventilation, and air conditioning (HVAC), and process heat. The system can be modularly configured for hybrid concentrating PV-Thermal (CPV-T) or thermal-only operation to meet specific customer demands. At a 20x concentration ratio, system output of 500 Wpe and 2 kWpt is expected, for a combined system efficiency of up to 75%. The MCT is constructed from mature, proven technologies and industry-standard processes. An installed system cost of less than US

Results from the first ANU-chromasun CPV-T microconcentrator prototype in Canberra

2/Wpe is targeted, and commercial availability is expected to commence in 2011.

Towards an innovative spectral-splitting hybrid PV-T micro-concentrator

A first prototype of the hybrid CPV-T ANU-Chromasun micro-concentrator (MCT) has been installed at The Australian National University (ANU), Canberra, Australia. The results of electrical and thermal performance of the MCT system, including instantaneous and full-day monitoring, show that the combined efficiency of the system can exceed 70%. Over the span of a day, the average electrical efficiency was 8% and the average thermal efficiency was 60%.

A Monolithic Microconcentrator Receiver For A Hybrid PV‐Thermal System: Preliminary Performance

A hybrid concentrator PV-Thermal (CPV-T) system for delivery of electricity and 150°C hot fluid in a structure suitable for roof-top installation on domestic, commercial, and industrial buildings is being developed by ANU in collaboration with the University of New South Wales, CSIRO, and industry partners. A first design based on beam-splitting utilising liquid-absorption filters is being analysed, with a study of the most suitable candidate fluids. An initial selection of four liquids was conducted; with the liquids subjected to accelerated tests to analyse their long-term performance and possible optical and chemical degradation. Some of the fluids showed optical changes after high temperature test and UV exposure, leading to slight yellowing.

A Review on Suitable Standards for Hybrid Photovoltaic/Thermal Systems

An innovative hybrid PV‐thermal microconcentrator (MCT) system is being jointly developed by Chromasun Inc., San Jose, California, and at the Centre for Sustainable Energy Systems, Australian National University. The MCT aims to develop the small‐scale, roof‐top market for grid‐integrated linear CPV systems. A low profile, small footprint enclosure isolates system components from the environment, relaxing the demands on supporting structures, tracking, and maintenance. Net costs to the consumer are reduced via an active cooling arrangement that provides thermal energy suitable for water and space heating, ventilation, and air conditioning (HVAC) applications. As part of a simplified, low‐cost design, an integrated substrate technology provides electrical interconnection, heat sinking, and mechanical support for the concentrator cells. An existing, high‐efficiency, one‐sun solar cell technology has been modified for this system. This paper presents an overview of the key design features, and preliminary el...

Evaluation Of Electrical And Thermal Performance Of A Linear Hybrid CPV‐T Micro‐Concentrator System

This paper will present an evaluation of the available standards and their considerations when using active‐cooled CPV systems, along with an initial assessment of the most appropriate tests, including additional test requirements, for hybrid Photovoltaic‐Thermal (PV‐T) systems in order to guarantee their long‐time electrical and thermal performance.

A hybrid solar linear concentrator prototype in India

Chromasun Inc. and The Australian National University have developed a low‐concentration, linear, hybrid micro‐concentrator (MCT) system suitable for urban rooftop installation. The system produces both electrical and thermal power, integrating the functionality of separate flat plate photovoltaic and solar hot water systems. The MCT system utilises industry‐standard components, including modified mono‐crystalline silicon one‐sun solar cells, commonly used in flat panel applications. The MCT manufacturing processes are designed around low‐cost methods, and tap directly into existing economies of scale. Initial test results without any system optimisation has demonstrated an electrical output of more than 300 W, and a thermal output of more than 1500 W at 950 W/m2 DNI.

Designing CPV Receivers With Reliability: Early Evaluation of Components

The technical and economic potential of solar linear concentrator systems in India is being analysed by The Australian National University (Canberra) and Anna University (Chennai). The main objectives of this study are to identify the markets for solar linear concentrator systems in India, and to evaluate the field performance of a new prototype system under specific Indian climate conditions. The new hybrid linear solar concentrator prototype is being installed at the Anna University campus. This demonstration and training prototype follows the well-known ANU CHAPS system design, but on a smaller scale, to simultaneously provide electricity and hot water. The technical potential of the new linear concentrator will be assessed on the basis of available local skills to maintain and operate the system, the local cost of installation including locally-sourced materials, and the economic value of the energy produced over the expected system lifetime.