Publications by Daniel Favrat | EPFL Graph Search

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Throughout the years LENI-EPFL spent a significant part of its research activities on heat pumps be it for industrial heat recovery or for domestic or district heating and cooling. Methodological contributions include the improvement of the formulation of the exergy efficiency indicators, including for a cantonal law on energy and in the energy integration techniques for industrial processes. Novel, socalled environomic, mono- and multi-objective optimisation analyses of large integrated systems with heat p

The modelling of natural gas combustion with detailed as well as reduced kinetic mechanisms has been subject to many publications already. Most of the mechanisms are validated at higher temperatures and ambient pressures. Only recently - in parallel to a gain of interest in the homogeneous charge compression ignition (HCCI) engine concept - there are more efforts trying to reproduce the low temperature chemistry, and in particular autoignition of natural gas under engine-like conditions. This work is part o

Unscavanged prechamber ignition has been developed at the Laboratory of Industrial Energy Systems to reduce the emissions from cogeneration spark ignition gas engines, operating with both natural gas and biogas. Demonstration has been made that a lean burn engine unit equipped with optimized prechambers allows efficient operation, while remaining below the Swiss limits [1,2]. Further development aims at using prechambers operating in autoignition mode similar to HCCI (Homogeneous charge compression ignition

Reliability of SOFC stacks is a complex and key issue. This paper presents a simulation study including some degradation processes, namely, interconnect degradation and the anode reoxidation potential. Quantification for these phenomena has been included i ...

An efficient control system is paramount for the operability of Fuel Cell systems since, in ideal cases, it allows the regulation of power output, temperatures and economic performance under a dynamic working environment where they need to operate. Although several control strategies, scenarios and methodologies have been broadly investigated, it is usually taken for granted that the measurements from the system, necessary for the control feedback, are correct. Nonetheless, when simple thermocouples are use

Although heat pump based district heating is often an obvious solution from an energy standpoint, adapting the delivery temperature to the most exigent users is detrimental to overall system performance. This pitfall can be avoided with a centralized plant of heat pumps, cogeneration units and an auxiliary furnace, supplemented by decentralized heat pumps. However, the problem of mixed energy production and delivery which this poses is complex and presents for the engineer the daunting if not impossible tas

A simultaneous optimization of the design and operation of a district heating, cooling and power generation plant supplying a small stock of residential buildings has been undertaken with regards to cost and CO?2 emissions. The simulation of the plant considers a superstructure including a SOFC-GT combined cycle, a compression heat pump, a compression chiller and/or an absorption chiller, and an additional gas boiler. The Pareto-frontier obtained as the global solution of the optimization problem delivers t

A new type of district energy network providing simultaneously heating and cooling services is being investigated. It is based on the use of CO2 as a heat transfer fluid by taking advantage of the latent heat of vaporization, to store and transfer heat across the network. The goal of the present study is to determine the performance of a CO2 network when applied to a real urban area. It focuses first on determining the requirements for the various thermal energy services for a part of Geneva's City Centre.

The present paper is the third and last part of an investigation on what determines reliability in fuel cell model identification. In continuation to the effect of experimental design (Part I) and a process method for stochastic calculation of a model's pa ...

In Switzerland like in many countries, many of the populated areas are located close to lakes or rivers, offering a large potential for the use of heat pumps. Although district heating is an obvious solution, adapting the delivery temperature to the most exigent users is detrimental to overall system performance. The best system configuration could avoid this pitfall by relying on a centralized plant of heat pumps with cogeneration, supplemented by decentralized heat pumps for the more demanding users. Usin

An attractive way toward a more rational conversion of fuel and biofuel is the decentralized power generation and cogeneration. The fuel cell-gas turbine hybrid cycles are emerging as the most promising candidates to achieve in decentralized generation comparable or higher efficiency than in large scale power plants. The present contribution is devoted to the design and optimization of an innovative concept of small scale Solid Oxide Fuel Cell – Gas Turbine hybrid cycle for residential applications. A 5kW p

Providing heat pumps for the retrofit of fuel based boilers in residential heating, is a short or medium term challenge and a major opportunity for a substantial reduction of greenhouse gas emissions. While effective solutions for improved high temperature lift, vapor compression heat pumps have been analyzed elsewhere, this paper specifically deals with the refrigerant selection aspects for alternative blends, using a multi-objective optimization algorithm. The objectives COP and specific heat output are c

Combined cycle power plants burning natural gas offer various advantages such as high efficiency, low environmental impact, smaller specific investments and shorter construction periods which lead to a more flexible response to uncertain future electricity demands. The synthesis (choice of configuration), the design (capacities and performance of components) and the operation (changes in thermodynamic parameters) have to respect thermodynamic, economic and environmental factors. Thermoeconomic and environom

Concern for the environment has been steadily growing in recent years, and it is becoming more common to include environmental impact and pollution costs in the design problem along with construction, investment and operating costs. To economically respond ...

Extending the idea of exergy to practitioners and policy makers is still a major challenge. Recently the "Canton of Geneva" in Switzerland introduced a new law governing the procedures of attribution of building permits for new or retrofitted city areas. A ...

A multi-objective evolutionary algorithm developed at the Laboratory of Industrial Energy Systems is used to determine the best technological solutions to satisfy the electrical needs of a remote community. Simulations of the community are based on a superstructure in which organic Rankine cycle, diesel engine, photovoltaic and other technology options (heat storage, cogeneration engine, cooling tower, parabolic through,...) are included in the form of modules. These modules model the most significant facto

In order to characterize a new SOFC stack design, to investigate degradation processes and to validate models, a diagnostic test station was designed and realized. It allows to characterize repeat-elements locally by measuring the local potential, current density and temperature over the active area. The active area is segmented in 18 small electrically insulated measurement points (segments), in addition to a main segment. The profile of current density was investigated up to an average of 0.6A/cm2 and 67%

Models for hydrolysis, fermentation and concentration process, production and utilization of biogas as well as lignin gasification are developed to calculate the heat demand of ethanol production process and the amounts of heat and power generated from res ...

Resources both physical and financial are scarce in most developing countries while environmental concerns are growing requiring a greater effort to rationally plan investments. Nowadays the methods for designing, planning and managing integrated energy systems, while holistically considering the major economic and environmental factors, are still embryonic. However, the first phase of the design is often crucial if we want to aim at a better resource management and at the reduction of energy consumption to

A dynamic model of a pure-solar combined-cycle power plant has been developed in order to allow determination of the thermodynamic and economic performance of the plant for a variety of operating conditions and superstructure layouts. The model was then us ...

Daniel Favrat

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20 ans de contribution du LENI-EPFL à la recherche sur les pompes à chaleur

Kintetic modelling of natural gas auto-ignition under engine-like conditions

Prechamber autoignition in natural gas engines

Simulation of SOFC stack and repeat elements including interconnect degradation and anode reoxidation risk

Control of a Solid Oxide Fuel Cell System with Biased Gas Temperature Measurements

An Environomic Approach for the Modeling and Optimization of a District Heating Network Based on Centralized and Decentralized Heat Pumps, Cogeneration and/or Gas Furnace (Part I: Methodology)

Multi-Criteria Optimization of a District Cogeneration Plant Integrating a Solid Oxide Fuel Cell - Gas Turbine Combined Cycle, Heat Pumps and Chillers

Performance and profitability perspectives of a CO2 based district energy network in Geneva's City Centre

Investigating Reliability on Fuel Cell Model Identification. Part III: Behavior of Assessment Criteria and Limits in Identification

Environomic Optimization of District Heating Network Systems with Both Centralized and Decentralized Heat Pumps.

Design & Optimisation of an Innovative Solid Oxide Fuel Cell – Gas Turbine Hybrid Cycle for Small Scale Distributed Generation

Screening for Refrigerant Blends in High-Temperature Lift Heat Pumps for Retrofit in Residential Heating

OPTIGAZ Part I: Thermoeconomic Modeling and Optimization of a Combined Cycle Plant linked to a Gas Network.

Environomic multi-objective optimisation of a district heating network considering centralized and decentralized heat pumps

The challenge of introducing an exergy indicator in a local low on energy

Multi-objective optimisation of remote community energy systems with consideration of noise disturbance

Investigation of Local Electrochemical Performance and Local Degradation in an Operating Solid Oxide Fuel Cell

Simulation of Fuel Ethanol Production from Lignocellulosic Biomass

Multiobjective Optimisation of integrated energy systems for remote communities considering economic and LCA factors

Thermoeconomic optimization of a combined-cycle solar tower power plant