Renewable energy based cooling and dehumidification system

• Main Author: Pal, Maurice Madu
• Other Authors: Anutosh Chakraborty
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/149875
• Institution: Nanyang Technological University

Singapore’s electrical energy usage on building air conditioning is 60%. Therefore, sustainable energy utilization at urban level is the ultimate solution moving forward and its development is fuelled by on-site renewable energy resource, waste to energy, clean energy utilisation and smart energy transportation. This project focuses on the utilisation of clean energy for the development of cooling and dehumidification, which not only reduces the electrical energy consumptions but also contributes to the reduction of Global Warming Potentials. Hence, the fundamentals of thermally driven adsorption assisted cooling cum dehumidification chillers and dehumidifiers are described with experimentally confirmed isotherms and kinetics data of MOFs + water systems. The report begins with the synthesisation and characterizations of zirconium-based metal organic frameworks with green synthesisation methodology. Later, the isotherms and kinetics of MOFs + water systems are measured. Employing control volume approach, the mass and energy balances for each component (such as the evaporator, condenser, and adsorption beds) of the proposed system are derived. The thermodynamic model is simulated with experimentally confirm isotherms and kinetics, MOFs properties and UA values of heat exchangers. The water uptakes on the assorted MOFs are presented under dynamic and equilibrium conditions. . Based on simulation results, the performances (in terms of cooling capacity and the COP) of two-bed adsorption cooling are calculated with respect to cycle time and different regeneration temperatures. At the cycle time of 500 s and the regeneration temperature of 80 °C, N-UiO-66 (Zr) shows the highest coefficient of performance (COP) and specific cooling power (SCP) of 0.39 and 0.55 kW/kg respectively. However, NH2-UiO-66 (Zr) shows the highest Δq of 0.32 kg/kg per adsorption-desorption cycle. This reports also investigate performances of MIL-101 (Cr) and AC-MIL-101 (Cr) MOFs assisted desiccant dehumidification system. At adsorption temperature of 30 °C and the relative humidity of 85 %, the water uptake of MIL-101 (Cr) is 1.0 kg/kg whilst the AC-MIL-101 (Cr) MOFs show the water uptake is 0.8 kg/kg. For the desorption temperature at 60 °C and relative humidity of 40%, the water loading of MIL-101 (Cr) is 0.08 kg/kg, and that for AC-MIL-101 (Cr) is found 0.1 kg/kg. The water transfer for MIL-101 (Cr) is found higher for the relative humidity ranging from 40% to 85%.