The present work aims to investigate the effect of inlet air cooling in conjunction with other input parameters on the exergetic performance of combined cycle power plants (CCPP). To mitigate the adverse effects of high ambient temperature on performance, the CCPP has been equipped with an inlet air cooler, which lowers the air temperature at the inlet of the compressor. Under a specific combination of input parameters, the analysis revealed a maximum increase in net specific work, efficiency, and exergetic efficiency of 14.16%, 3.93%, and 5.65%, respectively. Moreover, the effects of multiple input parameters were analyzed individually and in combination. This was done in order to identify the most influential exergy-affecting parameters for the CCPP, which turned out to be the degree of cooling, pressure ratio, and turbine inlet temperature. The simulated model is then subjected to two sets of multi-objective optimization using a genetic algorithm, considering the above parameters as design variables. According to the Pareto set of optimal solutions, cooling the inlet air by 16.5 K results in the highest net-specific work output and increased exergy destruction. Increased exergy destruction, on the other hand, is undesirable. However, if the cost of power per unit is high, this could be economically advantageous.

The global increase in refrigeration and air conditioning applications poses a severe problem as regards the environmental degradation caused by greenhouse gas emissions. This study introduces a novel approach wherein both evaporative cooling and passive cooling are integrated to unveil notable enhancements in energy and exergy compared to conventional air conditioning systems. Therefore, this work aims to enhance the thermal performance of a 1.5-ton split air conditioner (SAC) employing outdoor (condenser) evaporative and indoor passive cooling (EPC). The heat removal capacity of a condenser and SAC performance are greatly affected by the air temperature at the condenser inlet. Evaporative cooling serves to lower outdoor air temperature, while passive cooling minimizes the indoor cooling load. Design parameters encompass outdoor temperature (T_a = 30–44 °C), relative humidity (RH = 20–80%), and temperature reduction due to passive cooling (ΔT_R = 0.5–5 °C). A model is developed to calculate the temperature reductions of outdoor air through evaporative cooling in diverse climatic conditions, while the range of passive cooling degrees is obtained from previous experiments. Results indicate a substantial enhancement in the thermodynamic performance of the proposed system. The maximum coefficient of performance (COP) improvement of 68.66% is achieved at 44 °C outside temperature and 20% relative humidity. Annual energy savings, under extreme operating conditions, range from 358.4 kWh to 2116.8 kWh. The EPC SAC is identified as more sustainable than the conventional split air conditioner (CSAC). Moreover, the projected system is anticipated to recoup its costs within a relatively short period of 1.42 years.

The vapor-compression based conventional split air conditioners (CAC) consume a large portion of total electrical power and pose an alarming threat to global environment. The present work aims to reduce cooling load and power consumption of CAC by employing a dew point evaporative cooler (DPEC). DPEC consists of a counter flow type heat and mass exchanger with alternate layers of dry and wet channels. The intake air is sensibly cooled before entering the cooling room through the evaporator coil of the air-conditioner. Also, the working air (a part of outlet air in dry channel), after absorbing sensible heat of intake air and water vapors from the wet channel surface, is allowed to pass across the condenser coils. The intake dry bulb temperature (T₀ = 29-44°C) and specific humidity (ω₀ = 6-22g/kg) are taken as input parameters. While the cooled air entering the evaporator decreases the cooling load on the conditioned space, the compression work is also reduced due to increased heat transfer in the condenser. The maximum reductions in cooling load and monthly energy consumption at T₀ =44°C and ω₀ = 6 g/kg are found as 59.54% and 340kWh, respectively. The average energy savings with the DPEC system for hot-dry climate (from April to June) and hot-humid climate (from July to September) of New Delhi, India are observed to be 479.6kWh and 79.1kWh, respectively. The proposed system is found to payback in about 2.7 years.

An annular diffuser is a critical component of the turbomachinery, and its prime function is to reduce the flow velocity. The current work is carried to study the effect of four different geometrical designs of an annular diffuser using the ANSYS Fluent. The numerical simulations were carried out to examine the effect of fully developed turbulent swirling and non-swirling flow. The flow behavior of the annular diffuser is analyzed at Reynolds number 2.5 × 10⁵. The simulated results reveal pressure recovery improvement at the casing wall with adequate swirl intensity at the diffuser inlet. Swirl intensity suppresses the flow separation on the casing and moves the flow from the hub wall to the casing wall of the annulus region. The results also show that the Equal Hub and Diverging Casing (EHDC) annular diffuser in comparison to other diffusers has a higher static pressure recovery (C _p = 0.76) and a lower total pressure loss coefficient of (C _L = 0.12) at a 17° swirl angle.

An annular diffuser is a critical component of the turbomachinery, and its prime function is to reduce the flow velocity. The current work is carried to study the effect of four different geometrical designs of an annular diffuser using the ANSYS Fluent. The numerical simulations were carried out to examine the effect of fully developed turbulent swirling and non-swirling flow. The flow behavior of the annular diffuser is analyzed at Reynolds number 2.5 × 10⁵. The simulated results reveal pressure recovery improvement at the casing wall with adequate swirl intensity at the diffuser inlet. Swirl intensity suppresses the flow separation on the casing and moves the flow from the hub wall to the casing wall of the annulus region. The results also show that the Equal Hub and Diverging Casing (EHDC) annular diffuser in comparison to other diffusers has a higher static pressure recovery (C_p = 0.76) and a lower total pressure loss coefficient of (C_L = 0.12) at a 17° swirl angle.