Boiler | EPFL Graph Search

Furnace (central heating) and Condensing boiler A boiler is a closed vessel in which fluid (generally water) is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central heating, boiler-based power generation, cooking, and sanitation. Heat sources In a fossil fuel power plant using a steam cycle for power generation, the primary heat source will be combustion of coal, oil, or natural gas. In some cases byproduct fuel such as the carbon monoxide rich offgasses of a coke battery can be burned to heat a boiler; biofuels such as bagasse, where economically available, can also be used. In a nuclear power plant, boilers called steam generators are heated by the heat produced by nuclear fission. Where a large volume of hot gas is available from some process, a heat recovery steam generator or recovery boiler can use the heat to produce steam, with little or no

Optimal use of biomass in large-scale energy systems: insights for energy policy

Victor Codina Gironès, François Maréchal, Stefano Moret, Marco Nasato, Emanuela Peduzzi

Biomass chemical conversion processes allow the production of solid, liquid and gaseous biofuels, which can substitute almost any kind of fossil fuel and the associated greenhouse gas emissions. Despite this potential, high investment costs and conversion losses reaching up to 30-40 % of the input biomass energy content are major barriers to a higher penetration rate of the chemical conversion processes. Thus, biomass is nowadays predominantly used in direct combustion processes. However, conversion losses of chemical processes may be compensated by the fact that biofuels can be used in more efficient technologies for supplying energy services compared to standard raw biomass fuelled technologies. As an example, Synthetic Natural Gas (SNG) can be used in a cogeneration-heat pump system to produce heat, reaching an overall efficiency much higher compared to a wood boiler. In this work biomass conversion options are compared taking into account the complete energy conversion pathway, from the resource to the supply of energy services. The comparison is performed by evaluating the CO2 abatement potential of integrating these different pathways into a national energy system with a Mixed-Integer Linear Programming (MILP) modelling approach. The comparison is done with 56 scenarios, which are classified in two different groups. Scenarios belonging to the first group consider the choice of the biomass chemical conversion process as the only possible change in the system. In the second group, other changes are allowed in the energy system, such as an important deployment of efficient technologies. Results show that biofuels can allow for an overall better performance in terms of avoided CO2 emissions compared to direct combustion. This potential, however, depends on a wider deployment of efficient end-use technologies.

University of Ljubljana2016

Optimal use of biomass in large-scale energy systems: insights for energy policy

Victor Codina Gironès, François Maréchal, Stefano Moret, Marco Nasato, Emanuela Peduzzi

Biomass chemical conversion processes allow the production of solid, liquid and gaseous biofuels, which can substitute almost any kind of fossil fuel and the associated greenhouse gas emissions. Despite this potential, high investment costs and conversion losses reaching up to 30-40 % of the input biomass energy content are major barriers to a higher penetration of the chemical conversion processes. Thus, biomass is nowadays predominantly used for direct combustion. However, conversion losses of chemical processes may be compensated by the fact that biofuels can be used in more efficient technologies compared to standard raw biomass fuelled technologies. As an example, Synthetic Natural Gas (SNG) can be used in a cogeneration-heat pump system to produce heat, reaching an overall efficiency much higher compared to a wood boiler. In this work biomass conversion options are compared taking into account the complete energy conversion pathway, from the resource to the supply of energy services. The comparison is performed by evaluating the CO2 abatement potential of integrating these different pathways into a national energy system with a Mixed-Integer Linear Programming (MILP) modeling approach. The comparison is done with 56 scenarios, which are classified in two different groups. In the first group the choice of the biomass chemical conversion process is the only possible change in the system. In the second group, other changes are allowed in the energy system, such as an important deployment of efficient technologies. Results show that biofuels can allow for an overall better performance in terms of avoided CO2 emissions compared to direct combustion of biomass. To exploit this potential, however, it is necessary to link the production of biofuels to a wider deployment of the corresponding efficient end-use technologies.

2017

A method for taking into account seasonal storage in a district energy system optimisation problem

François Maréchal, Jessen Page, Jean-Loup Sylvain Robineau

In this work, a method for taking into account seasonal storage in an energy optimisation problem is developed. A master-slave optimisation procedure is applied, in which the master optimisation is an evolutionary algorithm, while the slave optimisation is a Mixed Integer Linear Programming (MILP) problem. The results of this optimisation can provide insight on the choice of technologies during the study of potential new district heating networks, and especially evaluate if a seasonal storage is worthwhile. The method developed is applied to a case study. The goal is to optimise the design of a micro-district heating system consisting of 3 buildings and a neighbouring source of industrial waste heat. The technologies considered are heat pumps, solar thermal collectors, a hot water storage tank, geothermal borehole seasonal storage, a gas boiler and industrial waste heat. The results show that, with the given assumptions, the use of combined seasonal and daily thermal storage can significantly reduce operating costs (by 65 %), fossil fuel consumption and CO2 emissions, with a payback time of 4.5 years compared to a reference solution with no storage.

2016

Optimal use of biomass in large-scale energy systems: insights for energy policy

Victor Codina Gironès, François Maréchal, Stefano Moret, Marco Nasato, Emanuela Peduzzi

University of Ljubljana2016

Optimal use of biomass in large-scale energy systems: insights for energy policy

Victor Codina Gironès, François Maréchal, Stefano Moret, Marco Nasato, Emanuela Peduzzi

Biomass chemical conversion processes allow the production of solid, liquid and gaseous biofuels, which can substitute almost any kind of fossil fuel and the associated greenhouse gas emissions. Despite this potential, high investment costs and conversion losses reaching up to 30-40 % of the input biomass energy content are major barriers to a higher penetration of the chemical conversion processes. Thus, biomass is nowadays predominantly used for direct combustion. However, conversion losses of chemical processes may be compensated by the fact that biofuels can be used in more efficient technologies compared to standard raw biomass fuelled technologies. As an example, Synthetic Natural Gas (SNG) can be used in a cogeneration-heat pump system to produce heat, reaching an overall efficiency much higher compared to a wood boiler. In this work biomass conversion options are compared taking into account the complete energy conversion pathway, from the resource to the supply of energy services. The comparison is performed by evaluating the CO2 abatement potential of integrating these different pathways into a national energy system with a Mixed-Integer Linear Programming (MILP) modeling approach. The comparison is done with 56 scenarios, which are classified in two different groups. In the first group the choice of the biomass chemical conversion process is the only possible change in the system. In the second group, other changes are allowed in the energy system, such as an important deployment of efficient technologies. Results show that biofuels can allow for an overall better performance in terms of avoided CO2 emissions compared to direct combustion of biomass. To exploit this potential, however, it is necessary to link the production of biofuels to a wider deployment of the corresponding efficient end-use technologies.

2017