Air-conditioning in textile mills plays a performance based system and is linked to quality and productivity of the textile production machines which are now highly sophisticated and sensitive. Air-condition has to be prioritized from the energy consumption point of view as the textile industry has been declared a high intensive industry by the Bureau of Energy Efficiency (BEE) of the Ministry of Power, India. Air-conditioning when done complete with refrigerant chillers can achieve the required temperature and humidity levels all round the year irrespective of ambient conditions. Air-conditioning systems must have equipments for filtration of air, motion of air, temperature control and humidity control. The filter media performance has direct bearing on the airflow of the fan and overall system resistance. The filter media commonly used are polyurethane foam type, acrylic/synthetic non-woven type for rotary and nylon mesh/pleat type for static filters.
All textiles are hygroscopic. That is, they absorb or release moisture depending on the relative humidity of the surrounding air. If the atmosphere is drier than the textile’s equilibrium relative humidity then the textile will give up its moisture to the air. If the air is very humid then the textile’s moisture content will increase. This moisture loss and gain occurs at every stage from the initial processing of the fibres through to final garment manufacturing, distribution and use by the consumer.
This change in moisture content has a direct impact on the properties of textiles, such as tensile strength, elasticity, fibre diameter and friction. A drop in the equilibrium relative humidity of a textile may cause it to be weaker, thinner, less elastic and therefore more brittle. It will also have more imperfections. By maintaining the air humidity whilst processing the fibres, this loss in moisture to the atmosphere is minimised.
Moisture loss during processing cannot be totally eliminated as the act of processing will increase the temperature of the material, which will cause it to become drier. However, by increasing the humidity of the air surrounding the textile directly after processing, the material experiences “regain”. Moisture is reabsorbed by the textile, thus improving the quality and performance of the fabric.