This work aims to investigate the potential electricity savings, as well as the potential decrease in LCoH and OPEX, that an integration of an industrial heat pump can have on a molten salt-based power-to-heat system with integrated thermal energy storage. The original system uses an electric heater to heat up molten salt, which acts as the heat transfer fluid of the system, from which heated steam can be produced and delivered at the output. The idea of integrating an industrial heat pump into this power-to-heat system is that it would heat up the molten salt for a certain temperature range in the beginning of the heating phase, while the electric heater would be used for the later part of the heating phase of the molten salt.  First, a background section is presented in order to provide background information about the topic at hand, primarily focusing on heat pump theory and avaliable process- and waste heat that could be used by an industrial heat pump. After that, a system configutaion is presented of the investigated power-to-heat system with all the components in it thoroughly explained. The methodology followed throughout this work is then presented, which includes the description of a mixed-integer linear program that is of fundamental importance in relations to this work, and used for conducting simulations from which much of the results is derived from.  When using a waste heat tempreture of 100°C and a sink temprerature of 250°C for the industrial heat pump, results show that the electrical power used in the system without an industrial heat pump can be decreased by 15,6%. Moreover, a maximum decrease of 13,4% of the LCoH and 16,6% of the OPEX can be achieved by the integration of the industrial heat pump. The biggest decrease, in regard to the LCoH and the OPEX, were for the countries with the highest average electricity prices, while a smaller decrease was shown for the countries with lower average electricity prices.  A cost increase for the industrial heat pump, which would affect the CAPEX of the system, was shown to have a small outcome for the LCoH savings, the major contributor was the OPEX of the system. If any impactful change for this particular power-to-heat system is desired, it's going to have to decrease the OPEX for best result, which is what the integration of an industrial heat pump aims at doing.

Le contexte énergétique global impose, durablement aux industriels la poursuite des efforts en matière d’efficacité énergétique nécessitant le déploiement de nouveaux procédés innovants éco-efficaces. Une meilleure gestion de l’énergie permet l’amélioration de l’efficacité énergétique globale des procédés ainsi que la réduction des émissions de CO2. Dans ces conditions, la récupération et la valorisation de la chaleur perdue apparait comme un potentiel pour atteindre ces objectifs. L’intégration d’une pompe à chaleur à haute température permet une valorisation de pertes calorifiques en satisfaisant des besoins de chauffage à haute température (>130°C) qui apparaissent simultanément dans certains procédés (distillation, séchage…). Malheureusement, les pompes à chaleur répondant à ces besoins industriels sont indisponibles actuellement. C’est dans ce contexte que s’inscrit la présente étude qui a permis le développement et la mise en place d’une pompe à chaleur à haute température utilisant l’eau comme fluide frigorigène. Les verrous techniques et technologiques limitant la faisabilité d’une telle machine ont été levés en concevant une nouvelle architecture de PAC et en développant deux types de compresseur : un compresseur bi-vis adapté et un compresseur centrifuge bi-étagé à paliers magnétiques. La mise en place de cette PAC munie du compresseur bi-vis est présentée. Un modèle dynamique de cette pompe à chaleur est développé avec Modelica en tenant compte de la présence de gaz incondensables dans la machine. Des modèles détaillés des compresseurs sont développés en fonction de leurs caractéristiques géométriques. Une étude expérimentale de la phase de démarrage est présentée montrant le processus de purge des incondensables et l'évolution de certains paramètres de la pompe à chaleur. Ces résultats expérimentaux ont été confrontés à des simulations numériques. Plusieurs modes de fonctionnement de la machine de récupération des pertes calorifiques sont simulés numériquement et analysés énergétiquement ainsi qu’exergétiquement. Le modèle de pompe à chaleur a enfin été intégré à un modèle de colonne à distiller montrant les économies d'énergie globales et les avantages environnementaux obtenus. / Currently, improving energy efficiency becomes a main challenge for all industrial energy systems. This challenge involves an improved recovery of wasted heat generated by several industrial processes. Large energy savings and potential environmental benefits are associated with the use of industrial heat pump mainly at high temperature levels (>130°C) unavailable on the market. The development of high temperature heat pump using water vapor as working fluid is investigated. Technical problems restraining the feasibility of this industrial heat pump are surmounted by a specifically designed heat pump, the development of a new twin screw compressor and a new centrifugal compressor with magnetic bearings. A dynamic model of this heat pump is developed using Modelica and taking into account the presence of non-condensable gases in the machine. Detailed models of the compressors are developed based on their geometrical characteristics. Experimental results of the start-up phase have been presented showing the non-condensable purging process and the evolution of some parameters of the heat pump. These experimental results have been confronted to numerical simulations. Several scenarios of industrial processes for high-temperature heat recovery and heat upgrading are numerically simulated and analyzed based on energetic and exergetic studies. The heat pump model has been integrated to a distillation column showing the global energy savings and the environmental benefits of using this developed heat pump.