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Go to Editorial ManagerConventional Refrigeration Systems (VCRS) are the most commonly used in industrial buildings and facilities. Conventional refrigeration systems are among the most energy-consuming sources in addition to causing more environmental problems and gas emissions, such as hydrocarbons (HCs) and hydrochlorofluorocarbons (HCFCs), are known to contribute to global warming and ozone depletion. Absorption Refrigeration Systems (VARS) are a good alternative to conventional refrigeration systems because they use low-grade heat sources and operate with environmentally friendly liquids. The most important of these heat sources is the heat wasted from engines, industrial processes and many other sources. The global objective of the study is a literature review on the different ways to operate the absorption refrigeration system using waste heat in engines that include exhaust gases and engine cooling water as well as renewable energy that includes solar energy. Reviews of the literature have demonstrated how the absorption refrigeration system can be used and operated using a variety of thermal sources. This study also supports the usage of ecologically friendly chillers to provide air conditioning and refrigeration, as it shows these systems have a lower performance coefficient when compared to conventional refrigeration systems.
In this paper, a theoretical study of the conventional solar-still system integrated via the design of heat recovery of air exhausted from the air conditioner condenser employing heat exchangers (WHRUs) was conducted. This study aims to improve desalination performance by compensating for the non-existence of sunlight during the night. A comparison was made between the desalination performance in the event of exposure to solar radiation and its performance in the case of exposure to the system (WHRUs). It was found that the (WHRUs) system has a minimal impact on the production of the conventional desalination rig during the night period, as the highest cumulative productivity in the presence of the (WHRU S ) reached (2.15 kg) in August. In contrast, the productivity dependent on solar radiation was (4.58 kg) for the same month, with the most significant percentage of improvement reaching (31.91 %).
Industrial gas turbines are central to electricity supply in hot-climate countries such as Iraq, yet their actual performance often deviates from design-point values because of high ambient temperatures, part-load operation, and component degradation. This study quantifies the operational, thermodynamic, and exergy performance of a 125 MW-class simple-cycle gas turbine in southern Iraq and identifies the principal sources of performance loss. High-resolution SCADA data (30,912 valid 15-min records) were analyzed over one full year using integrated energy and exergy balances. The unit operated predominantly at 75–90% of ISO-rated power, with an annual capacity factor of 0.41. At 90–100% load, the average net power output was 114.7 MW, the thermal efficiency was 0.321, the heat rate was 11,210 kJ/kWh, and the exergy efficiency was 0.343, corresponding to a 7–9% derating relative to ISO conditions. Thermal efficiency decreased by about 0.095 percentage points for each 1 °C increase in ambient temperature. Exergy analysis showed that the combustor accounted for approximately 59% of total exergy destruction, followed by the turbine (about 15%) and exhaust-related losses (about 21%). The results confirm the strong dependence of plant performance on ambient temperature and load. Near-term improvement should focus on sustained high-load operation and condition-based maintenance, whereas inlet-air cooling and waste-heat recovery should be evaluated in future techno-economic studies.