Performances of a simple exhaust mechanical ventilation coupled to a mini heat pump: modeling and experimental investigations

Nowadays, important efforts are deployed to reduce energy consumption in the field of residential buildings. Concerning new constructions, low-energy consumption buildings such as “passive” houses constitute a suitable solution to decrease the environmental impacts.In this kind of building, air tightness is improved and heating needs are reduced compared to traditional constructions. In order to ensure a good indoor air quality, controlled mechanical ventilation is required. Coupling a simple exhaust mechanical ventilation with a mini-heat pump appears to be a good solution for heat recovery.This latter system could provide an important (and even the whole) part of the heating demand related to domestic hot water. The system can also be coupled to the heating system of the building. Investigation on this system is carried out in the present paper. The first part of the paper presents the system, its components and its control. A semi-empirical numerical model of the whole system is presented. This model associates the sub-models of the main components: the compressor, the condenser, the evaporator (in this case, the ventilation heat recovery heat exchanger), the domestic hot water heat exchanger and the domestic hot water storage tank.The second part of the paper describes the experimental apparatus (and its control) designed to characterize the performance of the system in different operating conditions.Experimental data are presented and analyzed, which includes a calibration of the parameters of the model and a comparison with simulation results. Finally, the model is coupled to a building simulation model to determine the potential savings of such units.