Jindaporn Jamradloedluk

Adsorption Cooling System Using Metal-Impregnated Zeolite-4A

The adsorption cooling systems have been developed to replace vapor compression due to their benefits of being environmentally friendly and energy saving. We prepared zeolite-4A and experimental cooling performance test of zeolite-water adsorption system. The adsorption cooling test-rig includes adsorber, evaporator, and condenser which perform in vacuum atmosphere. The maximum and minimum water adsorption capacity of different zeolites and COP were used to assess the performance of the adsorption cooling system. We found that loading zeolite-4A with higher levels of silver and copper increased COP. The Cu6%/zeolite-4A had the highest COP at 0.56 while COP of zeolite-4A alone was 0.38. Calculating the acceleration rate of zeolite-4A when adding 6% of copper would accelerate the COP at 46%.

Experimental Performance of a Thermoelectric Heat-Pump Drying System for Drying Herbs

Abstract In this study we investigated thermoelectric (TE) heat-pump drying of laurel clock vine leaves, and the effect of drying-air temperature on the characteristics of the leaves. The TE drying system comprised four TE modules each with its own rectangular fin heat sink. The hot side of each TE module was fixed to its own heat sink; the cold sides were fixed to heat-pipe heat sinks and a drying chamber. The drying time depended on drying-air temperature. The heating capacity and coefficient of performance (COP) increased as the current supplied to the TE modules was increased. Calculated COP for the entire TE heat-pump drying system were 1.28 and 0.81 for drying-air temperatures of 50 and 40°C, respectively.

Biomass Fired Grate Boiler for Small Industrial Heating System

Agricultural residues have been more extensively used as alternative fuels for combustion system in boiler. This is because they are low cost and eco-friendly. Fired tube boiler with traveling grate combustor was developed and tested at steam pressure of 3 bar, in this study. Rice straw and bagasse were used as energy resources. The effects of fuel feed rate (12–17 kg/hr) and air to fuel ratio (4.6–8.0 kgair/kgfuel) on the steam production rate, combustor efficiency, heat exchanger efficiency, overall efficiency, and quantity of carbon monoxide emitted were experimentally investigated. At such ranges of fuel feed rate and air to fuel ratio, 15–20 kg/hr steam was produced with the combustor efficiency of 16.4–28.2, heat exchanger efficiency of 74.0–82.7, and overall efficiency of 14.7–22.4. An increase in fuel feed rate and air to fuel ratio resulted in the higher steam production rate, and efficiencies of combustor and heat exchanger. Overall efficiency, however, was not much affected by A/F ratio. Investigation on flue gas composition showed that contents of carbon monoxide decreased with increasing air to fuel ratio and decreasing fuel feed rate. Analysis of economic feasibility indicated that using rice straw and bagasse in place of diesel required the payback period of 1.87 and 1.89 years respectively. Rate of return for utilization of rice straw and bagasse were 57.3 and 57.5% respectively.

Notice of Retraction Increase in charcoal yields of fast-growing trees

Fast-growing trees are widely cultivated in the north-eastern of Thailand. The residues of them are plentifully. The aim of this research was the increase in yield of charcoal during cool down process under nitrogen atmosphere. Two kinds of wood residues, eucalyptus and bur-flower, were used for investigation. Charcoal production was carbonized in a high temperature resistant cement furnace. The procedure for converting wood to charcoal was the heating rate of 60 °C/min and holding at the temperature of 550-600°C for 90 minutes. All of air inlet and outlet were closed to stop combustion reaction and the nitrogen gas was then fed into the furnace at the absolute pressures of 200, and 300 kPa during cool down charcoal over night. Yield percentage, proximate components, and heating value of charcoals were compared to charcoals from normal cool down process without nitrogen and traditional method. The results showed that both eucalyptus and bur-flower charcoals under nitrogen atmosphere at the absolute pressure of 200 kPa got the highest yield percentage. Under nitrogen atmosphere at this pressure, bur-flower wood obtained the charcoal yield higher than that eucalyptus wood. While bur-flower charcoal cooled down with nitrogen at the absolute pressure of 300 kPa and without nitrogen gas yielded the lower than that eucalyptus charcoal. When compared with charcoal of traditional method, only charcoal from normal cool down process without nitrogen produced the lower yield. In addition, the production of charcoal without nitrogen and with different nitrogen pressure and traditional method did not significantly affect on fixed carbon, volatile matter, moisture, ash contents, and heating value.

Desorption Isotherms, Drying Characteristics and Qualities of Glace Tropical Fruits Undergoing Forced Convection Solar Drying

Solar energy, a form of sustainable energy, has a great potential for a wide variety of applications because it is abundant and accessible, especially for countries located in the tropical region. Drying process is one of the prominent techniques for utilization of solar energy. This research work proposes a forced convection solar drying of osmotically pretreated fruits viz. mango, guava, and pineapple. The fruit cubes with a dimension of 1cm x 1cm x 1cm were immersed in 35% w./w. sucrose solution prior to the drying process. Drying kinetics, color and hardness of the final products obtained from solar drying were investigated and compared with those obtained from open air-sun drying. Desorption isotherms of the osmosed fruits were also examined and five mathematical models were used to fit the desorption curves. Experimental results revealed that solar drying provided higher drying rate than natural sun drying. Color of glace fruit processed by solar drying was more intense, indicated by lower value of lightness and higher value of yellowness, than that processed by sun drying. Hardness of the products dehydrated by both drying methods, however, was not significantly different (p>0.05). Validation of the mathematical models developed showed that the GAB model was most effective for describing desorption isotherms of osmotically pretreated mango and pineapple whereas Peleg’s model was most effective for describing desorption isotherms of osmotically pretreated guava.