Explore the vast range of titles available.

In this work, a numerical and experimental study is performed to evaluate the affecting variables on energy efficiency of a novel regenerative evaporative cooler utilizing dew-point indirect evaporative cooling. For first time, an investigation is experimentally and numerically carried out to study the effects of the channel number on important parameters such as product temperature and humidity ratio. Investigations are carried out for five configurations with various channel numbers. The comparison of the numerical and experimental results is obtained and well accuracy observed. For the five studied configurations, the results show that with an increase in the number of channels, the outlet temperature decreases. For an inlet air flow rate of 100-600 m 3 /h, the cooled outlet flow temperature changes to the range of 23.4-30.7°C, 19.7-28.3°C, 18-26.4°C, 17.2-25°C and 16.6-23.8°C. For the configurations with finned channels, the percentage of increase in produced air temperature reaches 11.5% for HMX B, 18.6% for HMX C, 23.4% for HMX D and 26.9% for HMX E, as compared with HMX A.

Renewable cooling via absorption chillers being supplied by various green heat technologies such as solar collectors has been widely studied in the literature, but it is still challenging to get positive economic outcomes from such systems due to the large expenses of solar thermal systems. This study offers the use of a new generation of solar collectors, so-called eccentric reflective solar collectors, for driving single-effect absorption chillers and thereby reducing the levelized cost of cooling. This article develops the most optimal design of this system (based on several different scenarios) using multi-objective optimization techniques and employs them for a case study in Brazil to assess its proficiency compared to conventional solar-driven cooling methods. For making the benchmarking analyses fair, the conventional system is also rigorously optimized in terms of design and operation features. The results show that the eccentric solar collector would enhance the cost-effectiveness by 29%. In addition, using optimally sized storage units would be necessary to get acceptable economic performance from the system, no matter which collector type is used. For the case study, at the optimal sizing and operating conditions, the levelized cost of cooling will be 124 USD/MWh and an emission level of 18.97 kgCO 2 /MWh.

Natural gas is transported from production sites to end users through high pressure (5–7 MPa) transmission pipelines. At a consumption point or when passing into a lower pressure pipeline, the pressure of the gas must be reduced. This pressure reduction takes place at City Gate Stations (CGS). Currently in all of Iran's CGSs, valuable pressure exergy (potential energy) contained by the high-pressure natural gas is lost to the environment in throttling valves (expansion valves). In this study, based on a comprehensive program, the inlet and outlet properties and daily flow rates of natural gas through Khorasan province (Iran) CGSs were measured and recorded for a whole year. Based on these data, the amount of energy lost to the environment was calculated. It was found that the yearly average mass flow rate in Khorasan CGSs is 90.5 kg/s, and average energy destruction is 13,240 kW. Assuming a conversion efficiency of 75%, one can extract 9,930 kW of electrical power. Based on Iran's average daily natural gas consumption of 336 × 106 m3/day and assuming the same conditions at all CGSs as at Khorasan, 762 MW of electrical power could be generated by capturing the lost pressure exergy flowing through all of Iran's CGSs.