Réfrigération

Résumé

La réfrigération est le procédé permettant d'obtenir et de maintenir un système (local, produit, etc.) à une température inférieure à celle de l'environnement. Technologies de réfrigération Le principe de tout procédé produisant du froid, le principe est un transfert de chaleur depuis le système à refroidir vers l'environnement. Les deux technologies les plus répandues à grande échelle sont les systèmes à compression et les systèmes à absorption. Cycles continus à vapeur Ces technologies font intervenir un fluide frigorigène dont la vaporisation absorbe la chaleur. Depuis le , il est interdit de s'approvisionner en CFC (R12 - Dichlorodifluorométhane - CCl2F2). Depuis le , il est interdit d'utiliser des CFC même pour effectuer des interventions sur une unité hermétique. Ce fluide a été remplacé par le R-134a (1,1,1,2-tétrafluoroéthane CH2F-CF3) (gaz de substitution). Réfrigérateur à compression de vapeur Le réfrigérateur à compression de vapeur (à c

Source officielle

https://fr.wikipedia.org/wiki/R%C3%A9frig%C3%A9ration

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (25)

Publications associées

Chargement

Personnes associées (2)

Personnes associées

Chargement

Unités associées (2)

Unités associées

Chargement

Concepts associés (68)

Concepts associés

Chargement

Cours associés (13)

Cours associés

Chargement

Séances de cours associées (29)

Afficher plus

Séances de cours associées

Chargement

EPFL's District Heating Heat Pump - Performance Analysis for DIfferent Working Fluids

Sylvain Clément

The present case study is multi-criteria performance analysis of EPFL’s heat pump for different working fluids. The heat pump is based on a 2-stage vapour compression cycle which is modelled using the software Belsim VALI for 7 low-GWP refrigerants. The simulation of the heat pump over different typical periods allowed to estimate the yearly mean COP of the heat pump. R-600a, R-600 and R-717 are the refrigerants showing the higher thermal efficiencies (COP = 5.5-5.7) and thereby also the higher environmental and economical performances. According to the TEWI indicator, the leakages of low-GWP refrigerants are negligible compared to the CO2-eq. emissions from the electricity generation. The decrease in the isentropic efficiency when the heat pump does not work at its maximum capacity strongly affect the COP. Therefore it is recommended to implement a heat storage system to increase the number of operating hours without isentropic efficiency decrease.

2021

Chargement

Utility Optimization in a Brewery Process Based on Energy Integration Methodology

Helen Carla Becker, Monika Dumbliauskaite, François Maréchal

This paper presents a methodology aimed at improving the energy efficiency of a brewery applying process integration techniques. The different steps of the analysis are presented. The first step is the identification of the process energy requirements and the corresponding heat loads, which allows the definition of the process hot and cold streams. The Pinch Analysis of the brewery reveals a heat recovery potential of 36% by improving the heat exchanger system. In order to satisfy the minimum energy requirements, optimal energy conversion technology configurations are calculated, taking into account economic and environmental criteria. The integration of suitable utilities is considered (cogeneration engine combined with heat pumping and refrigeration systems) and the interaction between them is analyzed. In addition, a thermo-economic optimization is performed in order to determine the optimal heat pump operating temperatures. The results show the opportunity to reduce by 36% the brewery heating bill and by 44% the CO2 emissions through the set up of an optimized utility configuration when compared to the current one. In addition, the optimal integration shows that the cooling water consumption of the refrigeration can be suppressed and appropriately be replaced by a heat pumping effect. The comparison between French and German conditions shows that contrasting results can be obtained due to the different economic and energy supply configurations. The process system analysis shows that when considering the recovery of the plant organic waste, bio-methane can be produced and valorized in the cogeneration engine. In that case, it is demonstrated that the process can become self sufficient in terms of energy.

2010

Chargement

Cooling of a gas stream using a refrigeration process is a common industrial problem, with many possible flowsheet solutions. This problem has been investigated using two different multi-objective optimisation techniques, with the aim of comparing these techniques.

2008

Chargement