International audienceIn several situations, a heat pump for simultaneous heating and cooling (HPS) can be installed advantageously in buildings where simultaneous needs occur. Unlike a reversible heat pump that works alternatively in heating or cooling, a HPS operates under three modes: a heating mode, a cooling mode and a simultaneous mode. In this article, different types of buildings are simulated using Trnsys software to identify their needs for heating, cooling and domestic hot water production (DHW). The introduction of a ratio of simultaneous needs in heating and cooling (RSN) can qualify buildings in relation to the appropriateness of a HPS. Three kinds of buildings are investigated (a low-energy building, an office building and a retail space) under three different climatic conditions in France. As the design of a heat pump is highly dependent on the refrigerant properties, models of small-to-medium HPS using R407C, R290 and HFO1234yf are developed. Results of experimental tests on a 15 kW-heating-capacity HPS working with R407C were used to validate the numerical models of components and global model. Finally, a co-solving technique using two environments (EES and Trnsys) is used to compare the performance of the different refrigerants coupled to the building having the best RSN

International audienceHydrocarbons are today considered as promising alternatives to hydrofluorocarbons thanks to their low environmental impact and their easy implementation. However, some precautions have to be taken to thwart their flammability. European regulations impose to take stringent measures regarding components and to install heat pumps in unoccupied spaces. Nevertheless manufacturers keep working on components for hydrocarbons. In the frame of a research project on heat pumps for simultaneous heating and cooling, an R407C prototype working with a scroll compressor was built and tested. A near-industrial prototype is today being designed for propane with the help of recent modelling techniques. After having detailed the main issues regarding hydrocarbons as refrigerants, this article reviews scroll compressor modelling studies and presents the development of a thermodynamically realistic scroll compressor model. It was first developed for R407C and then adapted to thermodynamic properties of hydrocarbons and to other sizes of compressors

This article presents the evolution of a concept of air-source heat pump for simultaneous heating and cooling (HPS). A heat pump can simultaneously produce heating and cooling energies for collective residential buildings, hotels or highly-glazed office buildings. The heat pump prototypes operate under three main modes. (1) The heating mode produces hot water using heat available in the ambient air. (2) The cooling mode produces cold water and rejects heat to the ambient air. (3) The simultaneous mode produces hot water thanks to heat taken from the cold water, therefore becoming colder. During the simultaneous mode, two thermal energy amounts, for cooling and heating, are produced simultaneously. Therefore, it is interesting for the user that the heat pump operates in the simultaneous mode as much as possible. A winter operating sequence involving a heat exchanger for refrigerant subcooling enhances the performance of the machine. Two prototypes working with R407C and R290 (propane) were built consecutively and tested following European Standard EN 14511 in a climatic chamber. The experimental results show that the second prototype has a higher performance than the first one regarding exergy aspects thanks to not only the refrigerant choice but also to a better design of components.