bahram sabahi; Houshang Bahrami; Mohammad javad sheykh davodi,; Seyed Mohammad Safieddin Ardebili,; ehsan houshyar
Abstract
experiments were conducted on a stationary four-stroke, naturally aspirated, water-cooled, single-cylinder, compression ignition engine to study the effects of blending CNG with neat diesel in dual-fuel operational mode and the variation in engine coolant temperature on performance parameters. For this ...
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experiments were conducted on a stationary four-stroke, naturally aspirated, water-cooled, single-cylinder, compression ignition engine to study the effects of blending CNG with neat diesel in dual-fuel operational mode and the variation in engine coolant temperature on performance parameters. For this study, factorial experiments in the form of a randomized complete block design with three replications were used to analyze the statistical status of the data. The studied parameters were fuel ratio, engine speeds and coolant temperatures. All experiments were conducted at the governor control mode. The results showed that, torque, brake power and brake mean effective pressure (BMEP) in diesel-CNG dual-fuel mode at all engine speeds significantly increased compared to pure diesel. At low engine speeds, increasing the coolant temperature reduced the brake specific fuel consumption (BSFC) and brake specific energy consumption (BSEC). Also, in the diesel-CNG dual-fuel mode compared to the engine with baseline diesel fuel, BSFC and BSEC were significantly lower. Brake thermal efficiency (BTE) also showed a significant increase at high speeds and when using dual-fuel operational mode. However, raising the coolant temperature increased the BTE. When using the engine in dual-fuel mode and increasing the temperature of the coolant, the volumetric efficiency showed a significant reduction. Furthermore, raising the coolant temperature diminished the volumetric efficiency. Overall, it can be stated that the use of a diesel-CNG dual-fuel mode with a coolant temperature of 60 degrees Celsius at entire engine speeds has the best outputs on the performance and combustion characteristics of the engine.
Moein Mokhtari Sataiy; Houshang Bahrami; MohammdJavad SheikhDavoodi; Davood Momeni; Mohsen Soleymani
Abstract
In this study, technical and economical potential of using solar energy for heating cucumber greenhouses in Jiroft region were studied. For this purpose, the climatic suitability of the region was determined. According to the data and thermal requirement of greenhouse, capacity of a flat panel solar ...
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In this study, technical and economical potential of using solar energy for heating cucumber greenhouses in Jiroft region were studied. For this purpose, the climatic suitability of the region was determined. According to the data and thermal requirement of greenhouse, capacity of a flat panel solar water heater was calculated and was compared with the conventional system, gasoil heater. The results of paired t-test showed that there was no significant difference between the two greenhouses in terms of CO2 content, average temperature and relative humidity, but there were significant differences in terms of chlorophyll content and yield between the two greenhouses, at the probability level of one and five percent, respectively. There was a significant difference, with a higher average of conventional system. The results of data analysis in Kamfar software showed that in terms of economic indicators, the use of solar water heaters for heating greenhouses in this area is justifiable in the fifth year and the return on investment is 5.32 years.
