# Flexible Coated Conductive Textiles as Ohmic Heaters in Car Seats
## 6 Design of Heating Fabrics Seats and Thermo-Electric Response  
Heated textiles can be made in two ways: one by fabricating a piece of fabric and inserting an electronic framework into it, and the other by producing a yarn with electronic properties and developing textile products. Metallic wires were first utilized in textile clothing during World War II. Then, instead of metallic wires, more sophisticated conductive yarns with textile yarn characteristics began to be developed. Heating products can be made from knitted, non-woven, woven, and embroidered fabrics. Due to their high resistance, non-woven fabric heating components are only occasionally used. Woven fabrics exhibit significantly less resistance when compared to knitted textile fibres in the same geometrically heated area due to their structural differences [81]. Multifilament carbon-blended stainless-steel fibres with a mild resistance are being developed for appropriate heat-generating applications. According to reports, this particular variety of electro-conductive fibre is exceptionally inflexible and fragile in bending, which renders it inappropriate for textile applications [82]. The standard fabric architecture, including plain, twill-weave patterns or single jersey, interweave, etc., with a standard fabric GSM of 250 g/m\({}^{2}\), could be specified for flexible heating inside a textile structure. The fibre composition influences the system's washability and heating behaviour. Wool fabric, for example, has a higher heating performance than cotton fabric. As a consequence, the thermal efficiency of a textile-based electrical heating network appears to be lower than that of woollen materials if cotton is employed as the basis fabric for the electrical transmission system. As a result, selecting an appropriate fibre composition has a significant impact on the heating efficiency of the system. Overall, the area demanding heat must be enclosed with a flexible surface for efficient thermal effectiveness as a result of delivery via convection and conduction mechanisms [83]. Thus, textile-based electrical heating systems offer a major advantage in sustaining the human body's essential necessary heat levels by permitting greater contact with the flexible architecture and reducing heat loss. In addition, recent research on textile-based electrothermal networks has attempted to develop a product that can control and monitor body temperature in response to environmental change, particularly for outdoor sports such as skiing and snowboarding. The Ag-coated nylon yarns were stitched over the polyester base-fabric in parallel connection that can provide a parallel power supply for the fabrication of electrically heating fabrics. The subsequent resistance of the design is lower when connected in parallel, allowing it to generate huge heating effects. An additional weave was provided in serial fashion to connect with the power supply [84]. A further experimental process of the study was carried out at Ghent University's Centre for Textile Science and Engineering for the fabrication of heating mats. They produced distance fabrics with an electrically conducting heating source that could be produced in a single manufacturing method on a warp knitting machine. The design process clearly described the key parameters required for the calculation process, including the full length of the heating mats, the quantity of heat sources, and their length, as well as the exact trajectory. The desired heating mats were 50 cm by 30 cm in size. The current study included three design steps: (i) preparing the movement patterns of heating wires, (ii) estimating the resistance required to calculate the approximate power of the entire mat, and (iii) preparing and testing samples. The detailed methodologies for these steps are described below.