Kamaruddin Abdullah

The Comparison of Three Types of Indonesian Solar Box Cookers

This paper describes the influences which govern solar box cookers: HS 7534, HS 7033 and the newest design HS 5521. The best of solar cooker, type HS 7033 gave oven temperature of 202°C between 12:00 and 12:45 p.m. on October 7, 1997. Thirty-four units of this type have been field tested since September 1997. It was found that these solar cookers have a good heat storage capability, therefore they can be used for consecutive cooking. The optimization of the size, the aperture area, the insulator thickness, the oven volume and the reflector area leads to a new design, type HS 5521. Its volume is only 35% of the volume of HS 7033 and cheaper. The performance comparison of the last two solar cookers are described based on the data collected during testing with and without load. The HS 5521 has the same heat collection rate and is able to cook as fast as HS 7033.

THE SOLAR OVEN: DEVELOPMENT AND FIELD-TESTING OF USER-MADE DESIGNS IN INDONESIA

This paper considers the design, use, and social acceptance of solar cookers that are constructed by their users. Several generations of oven design are described and their field testing in Indonesia, are reported, the first generation design having been described in a previous paper. The second generation design reached 175°C in oven temperature, and it used only local materials in its manufacture. Results of field testing of sixty four units in East Nusa Tenggara Provence, Timor Island, Sulamu village, and at Maumere City of the Sikka Regency in Flores Island, all in Indonesia, are reported. Social observations via questionnaires and direct conversation were conducted as part of the field study. Preliminary results showed promising tendencies of acceptance (up to 28%), and the solar ovens proved their ability to cook effectively. The most recent generation of design has reached 202°C in oven temperature, while costing 10% less than the previous one. The dissemination of thirty units of this design in two villages in West Nusa Tenggara Province is reported on.

Exergy Analysis on Simultaneous Charging and Discharging of Solar Thermal Storage for Drying Application

Exergy analysis is considered as an effective tool and has been widely used for assessing energy status of a thermal process from thermodynamic point of view. In this article, the exergy analysis is applied to the assessment of sensible thermal storage for a solar drying system. The objective of this study is to evaluate the role of the heat transfer process to the simultaneous exergy charging and discharging of the storage system in relation to the solar drying system. The results show that exergy loss ratio, which was regarded as the fraction of transferred exergy to the drying chamber, varied with the charging time and reached a minimum value at a certain charging time. The minimum exergy loss ratio and the time to reach the value are strongly dependent on the number of transfer units (NTU). The ratio of exergy loss at NTU ≅ 0 was 86%, greater than the value of practical interest. Accordingly, the application of sensible heat storage for a solar drying system will exert only a small effect to the temperature of the drying air entering the drying chamber.

Transport Properties Of Cellular Food Materials Undergoing Freeze-Drying

The samples of sliced and mashed apples were freeze-dried by controlling their surface temperatures over the usual pressure range of commercial operations. The surface of sliced samples could not be maintained at above 10°C in order to prevent the frozen layer from melting, while that of mashed samples was allowed to heat up to 70°C. Thermal conductivities and permeabilities were determined by applying the uniformly-retreating-ice front model to the dried layer of the samples undergoing freeze-drying. The values of permeability for the mashed samples were found to depend on the ice-crystallization time during freezing. The results indicated that the drying rate of sliced samples was limited by the transfer rate of water vapor flowing through the dried layer. A cellular structural model is proposed for predicting the permeability of the dried layer, based on the resistance of the cell membrane to molecular transfer of water vapor.

Drying Of Vanilla Pods Using A Greenhouse Effect Solar Dryer

ABSTRACT This paper describes the basic design of the GHE solar dryer and evaluates the performance of the dryer when used to dry vanilla pods. From laboratory test results it was indicated that the average drying time for vanilla pods was between 49 to 53, 5 hrs, for the case of heating augmentation using coal briquette stoves. The total amount of coal briquettes used to produce drying air temperature between 33 C to 65 C and RH of about 34% during day time was 61 kg equivalent to 6.1 kW heating rate and the average electric energy usage of 36.5 kWh, respectively. Quality test results indicated that the dried products were of grade IA of the export quality standard with vaniline content of 2.36%.

RECENT DEVELOPMENT OF GHE SOLAR DRYING IN INDONESIA

Prototypes of greenhouse effect GHE solar dryer have been tested and their technical performances for drying of tropical products have been obtained. Quality of the dried products was comparable to the existing standard used in estate plantation. The latest drying experiment with fermented cocoa beans using mechanical stirrer, and with a stationary rectangular bin for coffee berries, showed that the developed drying system was capable of reducing the total specific energy to 6.2 MJ/kg and 5.2 MJ/kg water evaporated, respectively. Therefore, the results of the study suggest that the current design could now be used in helping the farmers and fishermen to produce better quality products.

Acceleration of Rural Industrialization Using Renewable Energy Technolgoy

Solar, wind, biomass and micro‐hydro can be found in abundant in almost all rural area throughout the world. Despite of the fact that there are already so many research results showing the potential application of these renewable resources to substitute fossil fuel and to increase added value of local products, however, up to now very view if any result that has been realized in significant way. A concept of Small Provessing Unit using renewable energy sources have been introduced in Indonesia since 1999, in which domestically developed conversion technology, such as the greenhouse effect (GHE) solar drying system has been applied to process agricultural products such as coffee, cocoa, soices, various types of fishes and sea weeds. In addition, hybrid nocturnal cooling method has also beeing developed and used to help the farmer in extending shelf life of tropical fruits and vegetables and therefore, contributed in reducing post harvest losses. The Small Processing Unit concept as well as the developed re...

Simulation to Design Indonesian Solar Cooker Type HS Using the Energy Profiles Information

Publisher Summary Simulation is essentially a numerical experiment that is done by altering certain design parameters to find out the possible improvement of a solar cooker box type and to predict the performance of a new design. The chapter describes a simulation to develop the design of Indonesian solar box cooker. The assumptions used and the physical considerations in designing are also discussed in the chapter. Simulations can generally produce information about effects of design-variable changes on system performance in relatively quick and inexpensive way. However, the physical experiment gives information that cannot be generated by this simulation such as a liquid droplet and a leakage at the glue because of the excessive heat. The numerical experiment indicates that the efficiency of the cooker can be further improved.