Enhancing the performance of conventional coffee beans drying with low-temperature geothermal energy by applying HPHE: An experimental study (original) (raw)
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Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 2020
Coffee is one of Indonesia's main commodity which competes in international market. However, Indonesia's coffee production still faces some problems. One of the main problems is for the drying process. Moisture contents of coffee need to be reduced to 12%. All this time, most coffee producers use conventional method by using heat source from sunlight. However, uncertain weathers become one of the factors which slows down the drying process. Therefore, the purpose of this research is to find and utilize an alternative energy to solve the drying process problem. One of energy sources which is possible to be used for those criteria is geothermal energy especially with low enthalpy that usually is used for daily activities such as bathing, cooking, and warming houses. In this research, Heat Pipe Heat Exchanger (HPHE) which consists of 42 straight heat pipes with staggered configuration is used for utilizing geothermal energy. The heat pipe has a length of 700 mm OD 10 mm with filling ratio of 50% and added by 181 pcs of aluminum with dimension size of 76 x 345 x 0.105 mm as a fin. Geothermal fluid is simulated by water that heated by 9000 watt heater. Temperature of hot water with range of 50, 60, and 70˚C and air speed of 0.2, 0.4, 0.6 m/s are variations for the experiment. The result shows that the highest effectiveness of HPHE is 78.8% with the temperature of 70˚C and 0.2 m/s air speed while the lowest effectiveness is 68.8% with the temperature of 50˚C and 0.6 m/s air speed. Other than that, the drying process with the temperature of 70˚C and 0.6 m/s air speed is the fastest while the slowest is at 50˚C and air speed of 0.2 m/s. This result proves that increasing the temperature and air speed lead to the less time needed for the drying process.
2007
Indonesia is a country rich in geothermal energy. Of approximately 20,000 MWe energy potential, only about 850 MW has been utilized for electricity purposes. There are not many direct utilization activities for various purposes that have been implemented. This paper discusses a design of a geothermal dryer for beans and grains drying that will be implemented in Kamojang geothermal field, West Java, Indonesia. Geothermal fluid waste from a Kamojang well of approximately 160 ̊C will be used to supply the equipment. The heat will be extracted to produce a room drying temperature, for which coffee bean will be used as an experimental grain to be dried. A tube-bank heat exchanger has been designed, consisting of 1-meter-staggered pipes of 2inches (50.1-mm) outer diameter. An air blower from one side produces air flow of varying velocities to flow heated air into a drying room on the other side. With a geothermal fluid flow containing a heat transfer rate of 1000 W and various air flow ve...
Thermal design of 5 kg capacity coffee bean dryer simulator using Geothermal energy
IOP Conference Series: Earth and Environmental Science
A coffee bean dryer simulator that would be able to fully simulate the whole process of coffee bean drying using heat recovered from geothermal energy source has been thermally designed. This simulator is planned to educate people living near the geothermal resources or power plants about the direct use of geothermal energy, especially in coffe drying. The maximum capacity of this simulator is 5 kilogram of fresh coffee bean that is dried using hot air at 45ºC and mass flow rate of 0,23 kg/s. The duration of drying is about 3000 seconds which should be adequate to represent the drying process. The heat exchanger proposed for this thesis is a compact heat exchanger with staggered pipe arangement. The total number of pipes is 10 pipes at 36 cm in length and 65 flat plate alluminium fins measured at 0,6m x 0,16m x 0,005m. The fin efficiency value and the overall surface efficiency value are 72% and 73% respectively.
Preliminary study on the utilization of geothermal energy for drying of agricultural product
2003
Indonesia is highly rich in natural resources. Volcanoes are spread over the Sumatra, Java, Bali and Nusa Tenggara islands in connection with a Mediterranean circumferential. The rest are volcanoes in Sulawesi, the Maluku archipelago and Northern Papua in connection with a Pacific circumferential. Volcanic activities create a potential source of geothermal energy. One of the famous geothermal energy centres in Indonesia is the Dieng plateau. It is also well known for tobacco and mushroom plantations. However, due to the heavy rainfall and drying problems the quality of the tobacco produced here is somehow still below the international standard. Therefore, a research into the utilization of geothermal energy for tobacco drying becomes very important. The research into the drying of tobacco leaves was conducted using an indirect heating system. The heat source for the dryer was geothermal steam. A certain amount of sliced tobacco leaves was placed into a tray dryer. Then the steam was kept flowing at a selected velocity. The moisture loss of the tobacco leaves was indicated by direct balancing of the sample and was then recorded at five-minute intervals. The experiment was stopped after one hour since the steam started to leak into the system. Using the moisture loss and time data, a drying rate curve was obtained. The effects of the steam flow rates and the sliced tobacco leaves layer thickness on the drying performance were investigated in this research. Experimental works showed that the increase of steam flow rate can enhance the drying performance, while increasing the layer thickness reduced the drying performance. However the high sulphur content in the steam caused rusting of the tray material and an unpleasant odour was produced.
Use of Geothermal Energy for Drying and Cooling Purposes
2010
Indonesia has the world’s largest potential of geothermal resources. However, only a small portion of these resources have been utilized to supply Indonesia’s growing energy needs. Some of geothermal power generation facilities can provide excess heat for the main power generation system but some have untapped steam from small wells. The purpose of this paper is to explore the possibility to utilize dry steam or hot water from the geothermal power plant for drying and cooling of locally produce crops and, which could help to increase value of the surrounding farms. Steam or hot water available from geothermal power plant will be combined with active and passive solar utilization methods. In the drying applications, geothermal energy may be used to dry several crops available in the area such as coffee berries, tea, rough rice or even fish from the nearby lake. In the cooling system, the possibility to combine the already tested nocturnal cooling system and steam powered absorption o...
Energy Analysis of a Hybrid Solar Dryer for Drying Coffee Beans
International Journal of Renewable Energy Development, 2020
In this study, hybrid solar drying of coffee beans was performed, and energy analysis was carried out, to assess the system’s performance, in terms of energy efficiency, compared to solar drying and the open sun drying method. The dryer has three compartments: solar collector for collecting solar radiation, drying chamber, and a Liquid Petroleum Gas burner, which acted as an auxiliary heater to assist the thermal energy. The drying chamber has four trays for placing the dried product. The initial moisture content of coffee beans was 54.23% w.b and was reduced to the final moisture content between 11-12% w.b. The coffee beans dried faster when subjected to the solar hybrid drying method, compared to other methods, with the dryer temperature of 40°C, 50°C, and 60°C. Results indicated that the coffee beans’ drying times varied from 10 to 14 hours. However, at temperature 50°C and 60°C for the 1st tray, the water content was reduced more rapidly compared to the other tray. From the resu...
Thermal Evaluation of a Hybrid Dryer with Solar and Geothermal Energy for Agroindustry Application
Applied Sciences
The process of drying at the agroindustry level is considered the most important stage for the storage and conservation of food, but an inadequate sizing of the systems can generate an excessive consumption of fuel and energy. In the case of the agricultural sector, especially in small and medium producers in Ecuador, they tend to dry cereals outdoors, spreading the product over black plastics, asphalt floors, or cements called “tendal”. This process depends on the weather conditions of the area and can take between one or four days of drying, tending to damage the product by fungi. On the other hand, certain producers build dryers empirically, using as the main fuel gas for domestic use, diesel, or firewood. Among the problems presented for these types of dryers are heat losses in the drying chamber as it is not thermally insolated, a lack of temperature control (above 60 °C) and drying speed, excessive fuel use, and 10% burned product, which are essential to control to obtain a qu...
Design of a solar and gas dryer to use coffee pulp in food processes in Peru
Caspian Journal of Environmental Sciences, 2023
In the central jungle region of Peru, within the wet processing of coffee, the coffee pulp is discarded. This objective is to design a dual solar and gas dryer with continuous operation, for the dehydration of waste from wet processing of coffee for human use. The proposed objective is part of a broader project to apply the circular economy in the use of waste from wet coffee processing financed by Pro Ciencia. The following procedure was followed. At first, a 100 kg/Bach capacity gas and solar system dryer was designed applying the proposed technology development methodology in mechanical engineering and secondly arriving at the construction of the prototype. The results are to have a design methodology and the built prototype of the dual dryer (solar and gas) of continuous and semi-automated operation that has a control panel to allow programming and monitoring the drying process in real time. At the end of the project, the proposal will allow a continuous dehydration of the coffee pulp with quality, low cost and the industrialization of its by-products such as coffee pulp flour, filters and functional drinks.
Evaluation of Geothermal Grain Dryers: Case Study of Menengai Grain Dryer
2020
Alternative applications of geothermal energy, also known as direct use have over the years gained popularity globally. One of the major applications is drying where geothermal heat is used to raise temperatures in the environment of a product with an aim of reducing their moisture content. Different types of dryers are designed to utilize geothermal energy depending on the product to be dried. In order to maintain a quality product after drying, a good dryer design with optimal drying parameters must be emphasized. Different geothermal dryers have been constructed and used in different countries to dry different agricultural products. Among these countries is Kenya whose first geothermal dryer was constructed during the colonial times in the as a community project, and has since been used in small scale to dry pyrethrum and maize in the Eburru geothermal region. Kenya has recently registered a new milestone after Geothermal Development Company (GDC) installed a modern semi-commercial batch geothermal grain dryer at the Menengai Geothermal Field. This paper explores the various types of geothermal grain dryers, their design, technical parameters and operational costs in comparison with the new grain dryer in Menengai with an aim to establish an optimal design and size of a grain dryer.