PERFORMANCE ASSESSMENT OF A NOVEL PNIPAM POLYMER DESICCANT COATED HEAT EXCHANGER

Desiccant assisted air conditioners provide an approach to meet the humidity and temperature needs of buildings by decoupling latent and sensible loads, hence improving the efficiency of air conditioning systems for hot and humid environments.The desiccant coated heat exchangers are used to control the latent load.This research work was carried out to evaluate desiccant coated heat exchangers (DCHX) system performance in terms of moisture removal rate, moisture removal capacity, moisture mass ratio, regeneration specific heat input.Poly (N-isopropyl acrylamide) (PNIPAM), a novel thermo-responsive polymer, has been produced and coated to heat exchangers in order to absorb atmospheric water vapor.DCHX went through a cyclic test (adsorption/desorption process) that may be regulated by adjusting its temperature with thermoelectric devices, such as Peltier devices.The development and investigation of cyclic performance of desiccant coated heat exchanger is made as per ASHRAE standard 139.The experiments were performed under different conditions by altering the temperature and humidity using a controlled environment chamber.The performance parameters like moisture removal capacity, moisture removal rate, moisture mass ratio, and regeneration specific heat input are calculated for measuring the cyclic performance of DCHX.It is observed that at higher relative humidity conditions, the moisture removal capacity and moisture removal rate are higher.At 90% relative humidity, the observed maximal moisture removal capacity and moisture removal rate are 0.121 kg/hr and 0.116 kg/hr respectively.Furthermore, the values of regeneration specific heat input are calculated, and they are dependent on humidity levels.Its values are lower at high relative humidity.