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Abstract This paper characterized the wood pellet and torrefied wood pellet fuel as compared to coal for 100 MW co-firing power generation plant. There were five experiments to characterise the chemical and physical properties of coal, wood pellet and torrefied wood pellet namely moisture analysis, Thermo gravimetric Analyser (TGA), Bomb Calorimeter, Organic Elemental Analyser and Scanning Electron Microscope (SEM). The moisture analysis result from moisture analyser and TGA shows that the moisture content of torrefied wood pellet is lower than wood pellet at 6.760% and 3.629%. Moreover, the volatile matter, hydrogen and nitrogen content of torrefied wood pellet is lower than wood pellet at 65.20%, 5.993% and 0.4078% correspondingly. The calorific value, fixed carbon content, ash and sulphur also increase in torrefied wood pellet at 20.68 MJ/kg, 28.85%, 2.321% and 0.1656% respectively. In general, torrefaction improve the fuel properties of wood pellet similar to coal. The 100 MW direct co-firing power plant provides less capital investment, operation and maintenance cost for low rate co-firing ratio. However, there is economic challenges for high rate co-firing substation of torrefied wood pellets.

The European Geosciences Union (EGU) brings together geoscientists from all over the world covering all disciplines of the Earth, planetary and space sciences. This geoscientific interdisciplinarity is needed to tackle the challenges of the future. One major challenge for humankind is to provide adequate and reliable supplies of affordable energy and other resources in efficient and environmentally sustainable ways. This Energy Procedia issue provides an overview of the contributions of the Division on Energy, Resources & the Environment (ERE) at the EGU General Assembly 2017.

Abstract This research is conducted to determine the limiting values of the geometric concentration when used with solar thermal system (thermoelectric generator) (TEG) to maintain desired hot and cold side temperatures for power generation. Experiments were conducted to determine the optimum solar concentration (aperture area/target area) using a thermoelectric generator sandwiched between the target plate and passive heat sink. A computer model is developed to solve the energy balance equations and find the optimum values for geometric concentration. It was observed that for the single configuration of heat sink and thermoelectric generator in a system, the trend of temperature difference between the hot and cold sides remain the same at different geometric concentrations. The optimum geometric concentration is determined for heat sinks in study. It is observed that with solar radiation intensity of 800 W/m2 and heat sink fin length of 0.15m the optimum geometric concentration is 13.

Abstract The work discusses a problem of harvesting and upgrading of ultra-low grade heat with thermochemical energy storage technology for space and domestic water heating in residential area. The laboratory scale prototype, operating on the principle of an open packed bed sorption reactor and using moist air as a heat/mass transfer fluid, is experimented. The range of experimental air temperature was set to 17–40 °C, which corresponds to the typical range of domestic waste thermal energy. The tested sorbent was a salt-in-matrix composite material composed of a silica gel containing 43 wt.% of calcium chloride (CaCl2) salt. Hygrothermal behavior and energy performances of the prototype control volume filled with 245 g of material, representing the reactive front of a thermal wave, were analyzed at constant inlet hydration conditions (water vapor pressure of 12.5 mbar). The average temperature lift was recorded as 9–13 °C, representing the amplification of a supplied heat on 23% – 75% depending on the inlet temperature. The average specific thermal power inside the material bed was measured to be 168–267 W kg-1. The apparent energy density, based on the prototype control volume, ranged between 1.0 and 1.6 GJ m-3. Taking into account the heat of water vaporization, the coefficient of performance of the process was determined to be 0.96–1.57.

Abstract It is state of technology in district heating systems to use sand as backfill material for district heating pipes (DHP). In conventional pipeline construction, Temporarily Flowable Backfill Materials (TFB) have been already used for backfilling the pipe zone. TFB consists of the excavated material, cement, water and optionally bentonite. Environmental and economic advantages are that the excavated material can be reused and that TFB requires no compaction. In order to embed district heating pipes in TFB, soil mechanical parameters of the TFB are required. Above all the resistance to temperature-induced axial displacement should be well-known in order to estimate the displacements of the DHP, as well as the stress distribution along the DHP. Compared to sand as a non-cohesive backfill TFB have remarkable adhesive contact stresses which result in considerable resistance forces. In this article, the contact behavior between TFB and DHP is described as well as the effect on the DHP statics. Therefore, the results of various laboratory tests are summarized and presented to understand the interface-resistance-characteristics (IRC) of the DHP/ TFB interface. Then, the deduced IRC was implemented in a computer program for some comparative calculations with sand and TFB. Finally, the results of cyclic loading are presented and discussed.

Swirl combustors have proven as effective flame stabilisers over a wide range of operation conditions thanks to the formation of well-known swirl coherent structures. However, employment of swirl combustors to work on lean premixed combustion modes while introducing alternative fuels such as high hydrogen blends result in many combustion instabilities. Under these conditions, flame flashback has been considered as one of the major instability problems that have the potential of causing considerable damages of the combustion systems hardware in addition to the significant increase in pollutant levels. Combustion Induced Vortex Breakdown (CIVB) is considered a very particular mode of flashback mechanism in swirling flows as this type of flashback occurs even when the fresh mixture’s velocity is higher than the flame speed, consequence of the interaction between swirl structures and swirl burner geometries. Improvements of burner geometries and manipulation of swirl flows can produce good resistance against this type of flashback. However, increase flame flashback resistance against CIVB can lead to an increase in the propensity of another flashback mechanism, Boundary Layer Flashback (BLF). Thus this paper presents an experimental and numerical approach that allows the increase in CIVB resistance by using diffusive air injection and simultaneously avoid BLF by changing the wall boundary layer characteristics using microsurface grids as a liner for the nozzle wall. Results show that using those two techniques together has promising potentials regarding wider stable operation for swirl combustors, enabling them to burn a great variety of fuel blends safely.

Power generation from the renewable energy sources is usually intermittent and uncontrollable which challenges the grid frequency stability. The smart control of loads is an effective means to mitigate the challenge. A decentralized control of heating loads -- industrial melting pots (MPs), was developed which dynamically changes the power consumption of loads in response to grid frequency. A thermodynamic model of MPs was developed and validated based on site measurements by Open Energi. An aggregation of MP models with the control was integrated with a simplified Great Britain power system model. Results showed that MPs are able to provide frequency response in a way similar to generators, which provide a means for the system operator to quantify the benefits of demand response.