New heat conversion technologies need to be developed and improved to take advantage of the necessary increase in the supply of renewable energy. The Organic Rankine Cycle is well suited for these applications, mainly because of its ability to recover low-grade heat and the possibility to be implemented in decentralized lower-capacity power plants. In this paper, an overview of the different ORC applications is presented. A market review is proposed including cost figures for several commercial ORC modules and manufacturers. An in-depth analysis of the technical challenges related to the technology, such as working fluid selection and expansion machine issues is then reported. Technological constraints and optimization methods are extensively described and discussed. Finally, the current trends in research and development for the next generation of Organic Rankine Cycles are presented.

Techno-economic survey of Organic Rankine Cycle (ORC) systems

How to effectively utilize low and medium temperature energy is one of the solutions to alleviate the energy shortage and environmental pollution problems. In the past twenty years, because of its feasibility and reliability, organic Rankine cycle has received widespread attentions and researches. In this paper, it reviews the selections of working fluids and expanders for organic Rankine cycle, including an analysis of the influence of working fluids' category and their thermodynamic and physical properties on the organic Rankine cycle's performance, a summary of pure and mixed working fluids' screening researches for organic Rankine cycle, a comparison of pure and mixture working fluids' applications and a discussion of all types of expansion machines' operating characteristics, which would be beneficial to select the optimal working fluid and suitable expansion machine for an effective organic Rankine cycle system.

A review of working fluid and expander selections for organic Rankine cycle

Developing thermoelectric materials with superior performance means tailoring interrelated thermoelectric physical parameters – electrical conductivities, Seebeck coefficients, and thermal conductivities – for a crystalline system. High electrical conductivity, low thermal conductivity, and a high Seebeck coefficient are desirable for thermoelectric materials. Therefore, knowledge of the relation between electrical conductivity and thermal conductivity is essential to improve thermoelectric properties. In general, research in recent years has focused on developing thermoelectric structures and materials of high efficiency. The importance of this parameter is universally recognized; it is an established, ubiquitous, routinely used tool for material, device, equipment and process characterization both in the thermoelectric industry and in research. In this paper, basic knowledge of thermoelectric materials and an overview of parameters that affect the figure of merit ZT are provided. The prospects for the optimization of thermoelectric materials and their applications are also discussed.

A review on thermoelectric renewable energy: Principle parameters that affect their performance

A review of thermoelectric cooling: Materials, modeling and applications

A review on the enhancement of figure of merit from bulk to nano-thermoelectric materials

https://hal.archives-ouvertes.fr/hal-00789884/document

Expanders for micro-CHP systems with organic Rankine cycle

Experimental investigation of a biomass-fired ORC-based micro-CHP for domestic applications

Aerogels are a special type of solid material with nanometre-scale pores <1/3000th the width of a human hair. Porosity is in excess of 90%, in some cases as high as 99.9%, and densities can be as low as 3 kg/m-super-3. Aerogels are essentially ‘puffed-up sand’ and are often termed ‘frozen smoke’. Their thermal conductivity (0.014 W/m K at room temperature) is the lowest of any solids, and they also have good transparency. The acoustic properties of aerogels make them effective insulators against noise, and aerogels have the lowest refractive index, and dielectric constant of all solid materials. The unusual properties of aerogels open the way to a new range of opportunities for their application in buildings. This paper provides information on their unique features and reviews the potential applications for aerogels in buildings as well as latest developments in the field. Copyright , Oxford University Press.

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A review of state-of-the-art aerogel applications in buildings

Comparative investigation of thermoelectric air-conditioners versus vapour compression and absorption air-conditioners

The continual increases in global energy demand and greenhouse gas emissions call for more and more utilization of sustainable energy sources such as biomass. Among the existing biomass conversion technologies such as combustion, gasification and biochemical approaches, combustion is the most mature and widely used conversion technology. Several biomass-fired combined heat and power (CHP) plants with capacities in the order of 1000 kWe have been demonstrated in several European countries. However, biomass-fuelled micro-scale CHP (1-10 kWe) suitable for domestic applications has yet to be commercialized or demonstrated. The micro-scale biomass-fired organic Rankine cycle (ORC) CHP system currently developed by the authors mainly consists of a biomass boiler, an ORC fluid evaporator, an ORC turbine, an alternator, a heat recuperator and a condenser. The boiler produces hot water which transfers heat to the organic working fluid via the evaporator. The generated organic fluid vapour drives a turbine to rotate an alternator, producing power. The expanded organic fluid vapour leaving the turbine transfers some of its heat to the recuperator and then is condensed by cooling water which can be heated to around 408C for domestic washing and under-floor heating purposes. The preliminary testing of the CHP system has been carried out initially with a 9 kW electric boiler and then with a 25 kWth biomass boiler. The experimental findings of these preliminary tests are analysed and presented in the present paper.

Guoquan Qiu

Papers

Expanders for micro-CHP systems with organic Rankine cycle

Experimental investigation of a biomass-fired ORC-based micro-CHP for domestic applications

A review of state-of-the-art aerogel applications in buildings

Comparative investigation of thermoelectric air-conditioners versus vapour compression and absorption air-conditioners

Preliminary experimental investigations of a biomass-fired micro-scale CHP with organic Rankine cycle