Nanofluid for thermodynamic solar system

Abstract

Solar concentration system with thermo-vector fluid made up of gas-based nanofluids and with suitably shaped receiver element of the solar radiation.

Description

RELATED APPLICATIONS[0001]This application is the U.S. National Stage under 35 USC 371 of PCT Application PCT / IB2012 / 053528.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]Object of the present invention is a particular kind of thermodynamic solar concentrator based on the use of gas-based nanofluids and particularly developed for high temperature applications. One of the main problems in the usage of high temperature solar systems is to individuate easily manipulated thermovector fluids guaranteeing the possibility to transport great thermal flows.[0004]2. Brief Description of the Prior Art[0005]In the current state of the art, at least two different kinds of thermo-vector fluids are used; the heat transmitting oils and the mixtures of melted salts. The heat-transmitting oil is one of the first fluids used in this field and is mainly disadvantageous owing to its physical-chemical nature; it cannot exceed temperatures of 390°, over which it begins to loose its peculi...

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Benefits of technology

[0009]Another advantage of the nanofluids in general concerns the increase in the coefficient of optic absorption with respect to the base fluid. The absorption is an optic property which is realized when, upon putting a portion of substance in contact with the electromagnetic radiation, it is able to absorb energy from the same radiation. Such an absorption is function not only of the nature of the substance, but also of the radiation and in particular of its wave length. The coefficients of absorption of the nanofluids result high, above all in the visible region. The use of gas-based nanofluids can produce a significant increase in the performance of the thermodynamic solar systems under the effect of the direct absorption of the solar radiation inside the receiver. Moreover, the use of gas-based nanofluids can make easier the thermodynamic solar plants control, since there is no need of great thermal accumulation systems, which today are indispensable in the plants which use the melted salts as thermo-vector fluid.

[0010]In the present invention it is proposed a solution alternative to the use of traditional heat transfer fluids (molten salts, synthetic oils and similar) or liquid-based nanofluid, by the use of a solar receiver transparent in which a gas-based nanofluid can directly absorb solar radiation, improving the thermodynamic performance of the solar system. Aim of the present invention is therefore a solar concentration system, which uses a gas-based nanofluid as thermo-vector fluid (or heat transfer fluid) through which solar radiation can be directly absorbed. Another aim of the invention is a suitable design of the receiver element of the above said concentration system.

Problems solved by technology

In order to overcome the technological limitations mentioned before about traditional heat transfer fluids (synthetic oil or molten salt) some experiments have been carried out in the world using air as the working fluid of the plant; however, these experiments have revealed considerable problems of technological character, mainly linked to the combination of high pressures and temperatures needed for the operation plant.

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