The degradation of ambient air quality in urban regions of India has been exacerbated by the expansion of automobile fleets and stationary engines. In response, the Central Pollution Control Board (CPCB), under directives from the Ministry of Environment, Forest, and Climate Change (MoEF&CC) and the National Green Tribunal (NGT), has implemented stricter emission norms, including CPCB IV+ standards for power generators. Concurrently, the escalating costs of diesel gensets, driven by the integration of advanced air-fuel systems and emissions control technologies, have necessitated the exploration of alternative fuels. Hydrogen-enriched compressed natural gas (HCNG), a blend of hydrogen and natural gas, has emerged as a promising solution for achieving low emissions while maintaining power performance. This study evaluates the application of an 18% HCNG blend in a genset engine initially compliant with CPCB II standards, achieving compliance with CPCB IV+ emission norms without requiring hardware modifications. Key calibration parameters, including injection timing, ignition timing, injection duration, and desired lambda, were optimized to ensure enhanced performance and emissions control. The in-cylinder combustion characteristics, including combustion pressure, temperature, rate of heat release (RoHR), and brake mean effective pressure (BMEP), were thoroughly analysed for both Piped Natural Gas (PNG) and the HCNG blend. The results indicate that the HCNG blend significantly reduces emissions, with reductions of 66% in carbon monoxide (CO) and 74% in methane (CH₄) compared to PNG. These findings underscore the potential of HCNG to serve as a transitional fuel, bridging the gap towards the adoption of pure hydrogen technologies. This study demonstrates that HCNG can achieve substantial reductions in regulated emissions while supporting cleaner and more sustainable energy systems, positioning it as a viable alternative for stationary power generation applications.

The growing reliance on air conditioning (AC) systems in residential and commercial buildings has led to significant increases in energy consumption and associated greenhouse gas emissions, underscoring the need for cost-effective and sustainable cooling technologies. In this study, the feasibility and performance of a 1-horsepower (1 HP) non-inverter split-unit AC system assembled entirely from locally sourced components were evaluated under controlled residential conditions. Essential parts, including copper tubing, aluminum fins, compressor units, and refrigerant gases, were procured from regional suppliers and integrated following standard Heating, Ventilation, and Air Conditioning (HVAC) design protocols. Performance tests were conducted across five rooms in a residential apartment-comprising a lounge (largest), masters bedroom, and three additional bedrooms of decreasing size-to assess cooling effectiveness. Using an infrared thermometer (IR8895), temperature metrics including saturation temperature, cooling rate, and peak cooling temperature were recorded. Initial room temperatures ranged from 23.5${ }^{\circ} \mathrm{C}$ to 26.2${ }^{\circ} \mathrm{C}$, while final cooling temperatures ranged from 16.1${ }^{\circ} \mathrm{C}$ to 16.9${ }^{\circ} \mathrm{C}$. Cooling time increased progressively with room size, extending from 10 to 100 minutes. Corresponding saturation temperatures were observed at 24.9${ }^{\circ} \mathrm{C}$ to 26.6${ }^{\circ} \mathrm{C}$, with saturation times between 3.24 and 5.43 minutes, and peak temperatures consistent with the final cooling levels. Calculated cooling loads were 28.8 W (small rooms), 47.0 W (medium rooms), and 65.93 W (large rooms), with respective power consumption values of 85.5 W, 142.6 W, and 199.6 W. The Energy Efficiency Ratio (EER) and Coefficient of Performance (COP) were determined to be 9.25 and 2.7, respectively, across room types. The results indicated that the locally assembled split-unit AC system delivered competitive cooling performance relative to commercial equivalents, particularly in terms of thermal regulation, response time, and energy efficiency. The use of indigenous materials and components did not compromise operational reliability or compliance with HVAC standards. These findings support the viability of locally fabricated AC systems as a sustainable alternative for effective residential cooling in resource-constrained settings.