Design and development of resilient air conditioning system towards net-zero

Ahmad, Muhammad (2024) Design and development of resilient air conditioning system towards net-zero. Doctoral thesis, Northumbria University.

Text (Doctoral thesis) ahmad.muhammad_phd(18045855).pdf - Submitted Version Restricted to Repository staff only until 25 January 2026. Download (8MB) | Request a copy

Abstract

The thesis presents the design, development, and investigation of a novel indirect evaporative cooler. The proposed system addresses the major limitations of conventional systems to facilitate commercial-scale expansion. The innovative design offers superior thermodynamic performance, high operational reliability, simple manufacturing, lower operational cost, and benign carbon footprints. The study involves conceptual design (a novel configuration), theoretical design (an improved correlation), simulation, fabrication, and experimentation of an advanced indirect evaporative cooler at generic cell and pilot levels. In the first step, a generic cell of 130 W cooling capacity is fabricated and tested experimentally. The system achieved a supply air temperature of 22-27 °C for an outdoor air temperature of 27 to 48 °C, a maximum temperature drops of 20 °C, and a coefficient of performance up to 32. Moreover, the current system benchmarking with the existing systems showed superior performance by achieving higher temperature drop, cooling capacity, and COP for the same area. Based on the experimental finding of the generic cell, a novel heat transfer coefficient correlation is developed for large scale system design which was unavailable earlier. The proposed correlation achieved a good agreement (±5%) with experimental data over a large operational range of outdoor air temperature (25 to 50°C) and airflow rate ratio (50-200%). Using improved heat transfer correlation, a pilot system of 1500 W cooling capacity is designed, fabricated, and tested. The experimental analysis shows that the system achieved almost a temperature drop of 20 °C, a specific cooling capacity of 150 W/m2 K and a COP of 28. Finally, the comparative economic and environmental analyses demonstrated that the proposed IEC system showed the lowest cooling cost of 0.016 $/kWh, followed by vapor compression, absorption, and adsorption chillers as 0.050 $/kWh, 0.094 $/kWh, and 0.174 $/kWh, respectively. Similarly, the IEC system produced three times less CO2 emissions of 2220 kgCO2/y compared to MVC chillers with 6342 kgCO2/y for a 10-kW cooling capacity. Overall, the proposed system exhibited excellent performance by achieving supply air temperature within ASHRAE comfortable zone. Besides, it showed advantages like high energy efficiency, simple manufacturing, lower cooling cost, and benign carbon footprints. Therefore, the proposed system is a potential solution for decarbonization of the future air conditioning.

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