Perpustakaan Digital ITB

Today the ardency to solve the global warming and the ozone layer destruction problems due to refrigeration system has been calling for developing the environment friendly refrigeration technologies. The adsorption system is an alternative way to alleviate these problems. Adsorption cycles have a distinct advantage over other systems in their ability to be driven by heat of relatively low, near ambient temperatures, so that waste heat below 100 oC can be recovered, which is highly desirable. Additionally, they have advantage of being environmental friendly i.e., both their ODP (Ozone Depletion Potential) and GWP (Global Warming Potential) are zero. Therefore, this research is to study the performance of the adsorption refrigeration using local activated carbon and methanol as a working pair. This research consists of two parts. The first is developed the fundamental experiment and the second is designed and predicted the performance of adsorption refrigeration system for ice maker. The experimental apparatus consisted of an adsorber containing the local activated carbon which is heated or cooled by a hot/cool water tank, methanol container, and evaporator/condenser. An adsorption process takes place when methanol was evaporated from evaporator and then adsorbed to the adsorber bed by heating the temperature of the bed from 30oC to 100oC. The desorption of methanol was also undertaken by cooling the temperature of the bed from 100oC to 30oC. The experiment is to investigate the adsorptive behaviour of methanol on the activated carbon surface. Thus, the activated carbon which gave the best performance from the data analysis is used to design the system. There were three sizes of the carbon were considered (mesh size 8×8 grain size is about 3-5 mm; mesh size 10×10 grain size is about 2.5-3 mm; mesh size 12×12 grain size is about 2-2.5 mm) and used with methanol in an experimental unit. Dubinin’s equation has been used to characterize the adsorption properties. It found that the carbon with mesh size 10×10 shows the highest value of the adsorbed methanol adsorption. Then, the activated carbon mesh size 10×10 is improved by using 10% mass additional salts which are sodium carbonate, sodium bicabornate, and sodium chloride. The results from experiment shown mesh size 10×10 of activated carbon with additional sodium chloride gave the maximum adsorption quantity and adsorption capacity. The Adsorption refrigeration system for ice-maker using methanol and developed activated carbon mesh size 10×10 with additional sodium chloride as working pairs was designed. The characteristics and performance of the system predicted by using lumped parameter method as an ideal system. The simulation could show that the system behavior; the profiles of temperature, pressure and adsorbed ytitnauq of adsorber. The optimal cycle time is about 3200 seconds when fo seulav eht the specific cooling power dna the coefficient of performance are about 79.5 W/kg and 0.16. The highest the coefficient of performance of the system is 0.169 at the operation time is adnuor 3450 seconds. The parametric study based on variation of desorption temperature, temperature of evaporator and temperature of condenser and; its evaporating temperature is low as about -15oC, and eht ice making capacity is adnuor 20 kg/h.