J Integr Sci Technol, 2014, 2(2), 76-79 . Article . Journal of Integrated SCIENCE & TECHNOLOGY Development of energy efficient Carbon Fiber based Convective Heater Priyanka H. Maheshwari, * R.B. Mathur Physics and Engineering of Carbon, CSIR-National Physical Laboratory, New-Delhi, India Received: 10-July-2014 ABSTRACT A heating element has been developed that uses processed fibrous carbon materials to serve as a conducting base, and a suitable binder material to increase its overall strength and performance characteristics. This has been further fabricated in the form of a wall heater. The device has been designed to work on natural convection currents without any forced air blast using fans and motors. The flexibility of the material enables its use in different shapes as room heaters, decorative wall heaters, as a heating element in electric iron, hot plates, heating pads etc. Various advantageous characteristics of the carbon fiber based heating element (over the conventional nichrome wire and other carbon based heating element) that contributes in the efficient working of the heater have been discussed, the most important being its low power consumption. The heater consumes less than 200 watt of power as compared to 1-2 kW ingested by the commercial heaters. Keywords: Carbon composite; heater; porosity; resistivity INTRODUCTION The favorable strength to weight ratio of carbon fibers and their excellent mechanical properties have led to their use in diverse applications such as aerospace, sports and transport sectors. Another familiar, but often less used chattels of carbon fiber is its electrical conductivity. Poly acrilonitrile (PAN) based carbon fibers are not only mechanically strong (tensile strength of 3530 MPa for T-300 grade), but also possess electrical resistivity in a range to make it suitable for heating devices. Processed metal wire products such as tungsten wire and nichrome wire, machined products of carbon materials such as anisotropic carbon materials and glassy carbon materials, and metal compounds such as silicon carbides are primarily used as resistive heating elements. 1-4 Among these, processed metal wire products are mainly used as heating elements for the heaters of consumer appliances, while carbon, metal compounds, and ceramics e.g. silicon carbide, lanthanum chromite, disilicides etc are mainly used for industrial ovens and other similar application. However, as conventional carbon heating elements are fabricated by machining them from large plates or blocks, the production process is not only complex and expensive, but it is also difficult to fabricate narrow or thin products with sufficient strength. In addition, as the products are machined from blocks, having a specific resistance value within a certain standard range; there is the problem that changing the shape is the only way to control heat generation. Researchers has used carbon as a heating material. 5 Attempts have been made to fabricate electrically heated systems from appropriately shaped carbon fabric 6, 7 and those containing carbon/graphite fibers, as such woven or stranded into the strips, ropes, sleeves or strands of threads alone or with other materials with a protective layer of elastomer or other materials to overcome carbon's extremely poor abrasion and kink resistance. 8-12 It was found that the coating used in this method reduced the carbon material flexibility and increased the difficulty of making electrical attachments to it, and making electrically continuous seams. Recently carbon nanotube and graphene based transparent heaters have also been demonstrated. 13, 14 The present study unveils a heating device incorporating strength and flexibility as compared to conventional carbon heaters and having sufficient heat generation efficiency in far infrared region. Moreover it is in the form of thin porous sheet, making it flexible and lightweight. High porosity further leads to the large exposed surface area of the material through which the heat is emitted thus increasing its overall thermal efficiency. The flexibility of the material enables its use in different shapes. These could have a wide range of applications such Address: Dr. Priyanka Heda Maheshwari Physics and Engineering of Carbon, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi, India Tel: +91 11 45608508 Email: hedap@mail.nplindia.org ---- Cite as: J. Integr. Sci. Technol., 2014, 2(2), 76-79. © IS Publications JIST ISSN 2321-4635 Journal of Integrated Science and Technology pubs.iscience.in/jist J. Integr. Sci. Technol., 2014, 2(2), 76-79 76