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The Department of Renewable Energy (RED) is undertaking of a research and development activities in the field of renewable energy technologies such as wind, hydro, solar and biomass. Also, the department carried-out training on construction of biogas digesters, undertook awareness and popularization of developed technologies to the Sri Lanka community.As commercial activities, the RED undertook repair of crematoria and incinerators, provided consultancy services for several solid waste disposal projects, etc.
Expertise in
  1. Thermal applications of Biomass energy
    •   Gasification systems
    •   Industrial combustion systems
    •   Cooking stoves
    •   Drying systems
2. Thermal applications of Solar Energy
3. Biogas technology
4. Incineration technology (Multiple chamber two stage burning system)
5. Crematorium technology (L.P.Gas and Producer gas)
6. Micro hydro testing
 
R & D PROJECTS
 
1. Grid Connection Of 100kwe Gasifier Based Power Generation System
 
During the year 2009 the focus of the research team working on this gasifier based power generation system was, on trouble shooting and repairing of the Cummins Gas engine of this system. Pertaining to this project the following activities were completed during the year 2009.
    Studying of the operational problems of the engine-generation system.
    Inspection of the engine by the agent of the supplier of this power generation system.
    Top end overhauling of the engine.
    Testing of the operation of the engine.
Due to unexpected technical problems that has been confronted in the gas controlling and engine – generator system it was not possible to continue the project to test the grid paralleling system which had already been installed. At the Research Planning Committee of NERDC it was decided to focus the attention on repairing of the engine and bringing the engine-generator and gas controlling system to the normal condition, before pursuing with grid connection.
 
Figure 1. Engine – generator system of 100kWe Power generation system Figure 2. Sampling producer gas for gas analysis
 
2. Conversion Of Diesel Fired Air Heating System To Fuel Wood Chip Fired System At Greenfield Organic Tea Factory At Haputhale.
 
This is a Joint research project carryout with Green Field Plantations (pvt) Ltd. The objective of this project is fuel switching from diesel to fuel wood chips obtained from sustainable fuel wood plantations. An agreement has been signed between the two parties to carryout the project on cost and resources sharing basis. During the year 2009 the team of research engineers of NERDC was able to design, develop and install an innovative feeding system to feed fuel wood chips in to the pre-furnace in which combustion of fuel wood takes place. The technology developed by NERDC for fuel switching from diesel to biomass includes a biomass pre-furnace, conveyer type fuel wood feeding system and the controlling system. The design, development, installation and preliminary testing were completed during the year 2009. Improvements and installation of the testing of the controlling system is continued. Arrangements are being made to transfer the technology within the first quarter of 2010.
 
3. Industrial Fire Wood  Stove
 
Objective
To develop user friendly, smokeless and efficient industrial fire wood stove for  small and medium scale industries, hotels, institutions, army camps and canteen etc.
 
Achievement & Progress
Field trials were done for kithul sap concentration, with collaboration of ITI and Ministry of Science and Technology. Technology is ready for transfer.
 
Special Features of the Unit
Capacity : 20 lit of liquid
Fire wood consumption  : 3.5Kg/hr
Portable, heat controllable
Air supply method  : By natural draft through a chimney.
 
4. Fabrication Of 10kW Gasifier
 
The 10kWe Natural gas engine/ generator imported from China was installed. Water load, the battery and the electrical installation were also completed. Arrangements were done to run the engine with LPG to confirm the genset’s proper operation, In this case, gas manifold was fabricated and two gas regulators, which can regulate the gas pressure as specified in the technical manual, were purchased to couple with two domestic LPG cylinders. The genset was run and loaded to deliver 20kW, it’s rated capacity. This test was done twice.
 
Later, LPG cylinders were uncoupled and the producer gas line from the gasifier was connected to the engine inlet without any modification. Anyway it was forecasted that there may be a requirement to increase the diameter of the gas inlet, when we use producer gas. The air/ fuel mixing unit was modified to keep the total energy content of the mixture by increasing the diameter( by 7 times) of the producer gas pipe connected to the mixing unit.
 
Present status
 
With this modification the engine/ generator was run and provided power up to 20kW with producer gas. The electronic governor of the engine worked to it’s set speed of 1500rpm. Efforts are being taken to improve the gas quality further ( to 50mg/ Nm3) to ensure the trouble free operation of the engine. R & D activities are still ongoing. 
 
5. Plug-Flow Type  Anaerobic Reactor
 
The Plug-flow type Anaerobic Digester is a better option than the continuous type, fixed dome anaerobic digester and the semi-dry batch type anaerobic digester, to get rid of organic solid and liquid waste matter generated in household level and institutional level. The advantage of this type is the ability to feed solid material( together with liquid material continuously. Fixed dome type continuous reactor needs the feed material as a slurry (in liquid form) and Sri Lankan type anaerobic digester cannot be used for continuous operation.
 
Objective
To provide a solution to waste as a renewable source of energy and solve two problems at once; Getting rid of waste and to protect environment and obtaining biogas as an energy source.
 
Project implementation:
The reactor was tested for leakages about 1week.To establish bacteria inside the reactor 50kg of cow dung was fed daily for 6 days. After-wards, it was started to feed the system with vegetable waste for another six days and then started to feed with jak fruit leaves. Similarly, grass, food residues etc. were fed into the system. During this period Displaced gas volume and pressure inside the gas holder were monitored continuously. Several tests were done varying the feed material to find out the variation of pH, COD and BOD across the reactor.
 
Conclusion
It was also observed that the digester operates very well with vegetable waste as the feed material. Though it works very well with food waste, a bit of a bad odour emission is involved with food waste. Since the bulk volume is high in grass and the hydrolysis process is slower with grass, there is a tendency of getting the digester inlet blocked. It was also observed that 1 m3 of the reactor volume is capable of disposing about 10kg of vegetable waste or kitchen waste. The solid matter is converted in to a liquid form during the process. The effluent has a fertilizer value and could be used for gardening after diluting 4 times with water.
 
To validate the results, test the digester with kitchen waste continuously.
 
6. Solid Waste Disposal-Over Ground Unit
 
Background
NERD Centre has introduced a dry batch system for anaerobic digestion of agricultural waste like rice straw which is an abundant source in Sri Lanka. Approximately 800 GT of rice straw is generated in Sri Lanka per year. The plant is constructed underground for ease of charging the feed. In such cases care should be taken to prevent the seepage of water. The pit should be pressure tight and watertight requiring some skilled people for design and construction of the digester, which is then result in high cost. Therefore some kind of convenient digester solution is required for this biogas technology to be much popular. This project was devoted for finding the possibility of using an over ground plastic tank as an alternative to conventional system.
 
Activities and progress
Typical methane yield of biogas varies from 55% to 65%. In this case, we got the same result. Therefore the quality of the gas is within the average range. For a plastic digester of 5 m3, the load, which could put in was not enough in order to get a considerable gas amount to fulfill the basic cooking and lighting needs. The load may be increased by crushing the straw before loading.
 
7. Bio Diesel Production From Waste Cooking Oil
 
Background
Sri Lanka largely depends on imported petroleum products for transportation. Recently many countries encourage the usage of bio fuels concerning the energy security, diversity, sustainability and GHG mitigation. Most of the Asian countries also promote bio diesel and bio ethanol usage in transportation and Sri Lanka is no exception. Several initiations have made by government and non-government organizations in Sri Lanka also. In this project, special concern on WCO was made, as WCO is used by small-scale restaurants and hotels for further cooking purposes and it create high health risk to the people.  
 
Activities and progress
Bio-diesel production is a chemical process for trans-esterification of the complex triglyceride molecule of the vegetable oil. The result is a mixture of fatty esters with properties close to fossil diesel. There are several methods to produce bio diesel and here we used the base catalyzed method as it has more advantages over the other methods.
 
 
 
The specific gravity, viscosity and flash point obtained were in the range of ASTM standard values for bio diesel. Further testing and engine trials are needed for identifying the possibility of application.
 
8. Finding And Testing Locally Available Materials To Use As Desiccants For Air Conditioning Applications
 
Background
Building consumes large portion of national energy production in Sri Lanka. Air conditioning and mechanical ventilation represents almost 60% of building   electrical energy consumption. Finding an economically affordable and environmentally feasible way to providing the human comfort is a need of the era.
 
Activities and progress
An experimental investigation of the performance of locally available solid desiccant materials for dehumidification in air conditioning was carried out. In the study, coir fiber, granular activated carbon and sawdust were used as the working desiccant in a cylindrical bed. Commercially available spherical particles of silica gel (indicating type) were used for the comparison purpose. The reduction of RH, the increase of temperature, the effect of air flow velocity on the performance of the desiccant bed was discussed. Moisture desorption characteristics of materials were identified, by conducting batch-drying tests. Findings of this research shows that locally available materials can be used as desiccants for dehumidification in air conditioning, instead of using chemical desiccants such as silica gel. Dry coconut coir fiber is the best compared to the other materials. But, there is a possibility to use other materials also as good desiccants.
 
9. Desiccant Cooling-By Using Locally Available Materials
 
Background
Based on the findings of the minor research on “Finding and testing locally available materials to use as desiccants for air conditioning applications”, full testing of the system with online regeneration was recommended before applying these findings practically. And also, the mathematical modeling of the system was also recommended in order to optimize the system.
 
Activities and progress
The modeling part and the testing part is currently being carrying out simultaneously.
 
10. Bricketing of Saw Dust
 
Background
Sawdust was pressed by using hydraulic jack by applying various pressures with clay and cow dung as the bonding material. Cow dung is more suitable than clay for this purpose than clay but the more suitable cow dung and sawdust ratio is 1:1. Therefore the pressing was done without using any bonding materials but with a high pressure. 
 
Activities and progress:
First the sawdust was pressed in a 2”x3”dia. by giving a pressure of 10,000 PSI. Then the pressing was successful and could get a good quality bricket. The pressing ratio should be at least 3:1. This bricketing can be done successfully by giving a high pressure (more than 10,000 PSI) proportionately to the size of the bricket by pressing the bricket from both ends not slowly but a little bit fast.
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DEPARTMENT
Department of Agriculture & Post Harvest Technology
Department of Civil Engineering
Department of Design Fabrication & Consultancy to Industries
Department of Electrical, Electronic & Mechatronic
Department of Energy and Environmental Management
Department of Renewable Energy
Department of Techno Marketing
   
 
 
 
 
 
 
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