• Energy Research
• 12. Responsible consumption close
• Energy Procedia close

Abstract Renewable generation technologies (e.g. photovoltaic panels (PV)) are often installed in buildings and districts with an aim to decrease their carbon emissions and consumption of non-renewable energy. However, due to a mismatch between supply and demand at an hourly but also on a seasonal timescale; a large amount of electricity is exported to the grid rather than used to offset local demand. A solution to this is local storage of electricity for subsequent self-consumption. This could additionally provide districts with new business opportunities, financial stability, flexibility and reliability. In this paper the feasibility of hydrogen based electricity storage for a district is evaluated. The district energy system (DES) includes PV and hybrid photovoltaic panels (PVT). The proposed storage system consists of production of hydrogen using the renewable electricity generated within the district, hydrogen storage, and subsequent use in a fuel cell. Combination of battery storage along with hydrogen conversion and storage is also evaluated. A multi-energy optimization approach is used to model the DES. Results of the model are optimal battery capacity, electrolyzer capacity, hydrogen storage capacity, fuel cell capacity and energy flows through the system. The model is also used to compare different system design configurations. The results of this analysis show that both battery capacity and conversion of electricity to hydrogen enable the district to decrease its carbon emissions by approximately 22% when compared to the reference case with no energy storage.

AbstractUsing a low supply water temperature in heating conditions and a high water temperature during cooling can increase energy efficiency, use renewable energy sources, and provide a comfortable and healthy indoor climate. High temperature cooling and low temperature heating is achieved by reducing temperature difference in heat trans er and energy transportation process. The losses in temperature difference can be classified into three types: by heat/moisture exchange; by energy transportation through air/water circulation; by indoor terminal that releases heat/cooling to indoor condit oned space. The air handling process of HVAC system and indoor terminals are the key factor of reducing temperature differen e.Aiming at the losses in HVAC system, Annex 59, titled High Temperature Cooling & Low Temperature Heating in Buildings, is a new international cooperative work under the framework of International Energy Agency (IEA) Energy in Buildings and Communities (EBC). This paper introduc s the background, scope, objective, structure and deliverables of Annex 59. Annex 59 will try to present a new perspective and a new concept to analyze HVAC system in buildings. The goal of the Annex is to build up new concept of analyzing HVAC system from the perspective of reducing mixture loss and transfer loss and th n apply it in high temperature cooling and low temperature heating system.

Abstract The deeply decarbonized energy economy would be achieved by the efficient power generation and low-carbon end-use equipment and infrastructure, which relies on the fixed cost investments in these items. In this study, we calculated the societal costs by the incremental energy system costs, which are defined the cost of producing, distributing, and consuming energy in a decarbonized energy system. We assess the transformation of the energy system including the major changes in energy supply and end use technology and infrastructure and its related energy costs. The investments in the highly efficient end use of energy, decarbonization of electricity and other fuels including biomass, petroleum, coal, natural gas and switching of end uses to electricity and other low-carbon supplies are calculated. The primary results show that the reference case shows a modest 15% increase in total final energy use, a 9% increase in CO2 emissions relative to 2014 levels, while the deep decarbonization case shows a 20% decrease in total final energy use and an 65% reduction in total emissions. The total societal costs, calculated by summing these three categories costs can be used for assessing the expected cost to achieve the target of greenhouse gas emissions reduction, which can provide theory for implications of low-carbon technology and infrastructure changes for the energy economy and policy.

Abstract The increasing attention toward climate changes and the recent strategic policies to stabilize and reduce CO2 emission is promoting research in the field of carbon capture, storage and more recently utilization technologies, whereby CO2 is captured from industrial flue gas, reused if possible or permanently stored in geological formations, such as depleted oil or gas fields and saline aquifers. In this scenario, Sotacarbo is leading the “Centre of Excellence on Clean Energy” research project, funded by the Regional Government of Sardinia, which aims to develop technologies for low emission power generation and for CO2 capture, utilization and storage. Among these technologies, CO2 utilization by hydrogenation and photoelectrochemical reduction are experimentally studied in the Sotacarbo laboratories. This work presents a general overview of the researches (carried out in close cooperation with the University of Cagliari) on CO2 utilization by conversion into liquid fuels, with a description of the research facilities and a hint on preliminary experimental results.

AbstractWith the lack of a management budget and weak policy for waste management of local communities in developing countries, especially for clusters that have the amount of garbage less than 5 tons per day, open dumping or open burning is the most common municipal solid waste (MSW) management, leading to severe impact on the environment. This study focuses on the sustainable development and eco-friendly waste management concept for these local communities. First, public participation campaigns with the 3R's concept (Reduced, Reuse and Recycle) must be launched to reduce and separate waste from households to be mixed with combustible waste, organic waste, and recycled waste. If the separation at the source is successful, the treated waste of about 2.5 tons is divided into wet and dry fractions. The wet fraction can be easily treated by conventional composting to produce soil conditioners and generate income for communities. The dry fraction must be treated by an incinerator. However, due to the high moisture content and low heating value of the waste, the incinerator needs to run with additional fossil fuel, causing high operating costs. Therefore, a novel hybrid incineration-gasification system has been introduced in this study to use Refuse Derived Fuel (RDF) prepared by dry fraction as feedstock to a downdraft gasifier. The producer gas generated from the gasifier can be used to substitute fossil fuel. This sustainable and eco-friendly model of waste management can be used as a prototype model for other rural areas in low or low-middle income countries.

AbstractElectrochemical splitting of calcium carbonate (e.g., as contained in inexpensive and abund ant minerals such as limestone) is proposed as a novel method of forming hydroxide solutions that can absorb, neutralize, and store carbon dioxide from the air or from waste streams. CaCO3 is dissolved in the presence of the highly acidic anolyte of a saline water electrolysis cell, forming Ca(OH)2 and H2CO3 (or H2O and CO2). By maintaining a pH between 6 and 9 in the resulting solution, subsequent hydroxide reactions with CO2 primarily produce dissolved calcium bicarbonate, Ca(HCO3)2. Thus, for each mole of CaCO3 split, there can be a net capture of up to 1 mole of CO2. The resulting dissolved Ca(HCO3)2 can be diluted and stored in the ocean, or in reservoirs on land or underground. Net process cost is estimated to be <$100/tonne CO2 mitigated.Other potential co-benefits of the approach include: i) production of significantly carbon-negative H2 if renewable - or nuclear - derived electricity is used as the power source, ii) the option of locally producing electricity and freshwater via fuel cell oxidation of the H2, iii) direct neutralization of ongoing ocean acidification if the Ca(OH)2 generated is added to seawater, iv) preservation or enhancement of otherwise threatened marine shellfish and coral populations, via CO2 absorption and Ca(HCO3)2 formation in or addition to the marine environment, and v) safe ut ilization of the ocean’s vast carbon storage and energy production potentials for CO2 mitigation and “super green” hydrogen generation.

Abstract Ventilation systems are of vital importance for buildings, not only to provide acceptable thermal conditions and air quality for occupants, but also with regards to energy usage. Impinging jets can be encountered in many ventilation strategies which have major impacts on the acoustic environment and energy performance. The self-sustaining tones can be generated in such applications where a feedback loop is installed in the system. This phenomenon is explained by the corollary of Howe who shows that the origin of noise in such configurations can be attributed to fluid rotations. Howe highlights the role of phase conditions between the vorticity, the velocity of the flow and the acoustic velocity for the optimization of energy transfers between the turbulent kinetic energy and the sound field. In this work, we use 2D-PIV technique and a microphone respectively to measure the kinematic fields simultaneously with the acoustic generation for a rectangular jet impinging on a slotted plate. This study aims to investigate the transfers between the turbulent kinetic energy and the sound field for two Reynolds numbers presenting a high and a low noise levels. It is shown that phase conditions are necessary for the optimization of energy transfer which allows the installation of the self-sustained loop in the flow. It was found also that the change of the aerodynamic mode which is directly related to the self-sustained frequency amplifies the sound intensity and promotes the transfer of energy to the acoustic field.

AbstractWorld-wide coal reserves can supply the global demand for primary energy for several centuries. However, low thickness and structural complexity may constrain the economic exploitation of many coal deposits. Taking into account these circumstances, underground coal gasification (UCG) can offer an economical and sustainable approach for coal exploitation and subsequent feedstock generation from the syngas. The UCG process produces a high-calorific synthesis gas mainly consisting of methane, hydrogen and carbon dioxide, which can be used for electricity generation or feedstock production at the surface. Considering the latter, the Urea process can be applied to establish the nitrogen based fertilizer carbamide (CH4N2O). The required feedstock for carbamide production in the Urea process can be supplied by UCG syngas. The aim of the present study was the development of an integrated carbon utilisation concept based on the coupled UCG-Urea process. A significant amount of carbon dioxide from the UCG synthesis gas is required for carbamide production in the Urea process, while the excessive carbon dioxide can be re-injected into the cavities resulting in the coal seams and surrounding strata after the gasification process. Thus, a new approach for utilisation of carbon dioxide resulting from coal combustion was developed to provide a coupled technology also comprising geological storage of excessive carbon dioxide. A theoretical feasibility study considering UCG-Urea process economics and potentials of UCG and carbon dioxide storage in the gasified strata was conducted for a selected study area in northern Bangladesh revealing the high competitiveness of the combined technology on the international feedstock markets.