Conference Year

July 2018


heat recovery, liquid desiccant, twin-tower, climate classes, energy saving


A significant share of the energy demand in high performance buildings is related to mechanical ventilation. Aside traditional heat recovery devices, liquid desiccant system can play a role. The performance of liquid desiccant devices and consequently their potential in energy savings is complex to estimate due to the influence of process parameters as well as the physical parameters of the fluids. A simple twin-tower configuration has been proposed as a reference system for assessing the control strategy and the potential of this technology to reduce the ventilation load. It consists of one absorption tower that treats the outside air and one that uses the exhaust air to regenerate the liquid desiccant. This configuration acts as a heat exchanger between the outlet and exhaust air streams with the liquid desiccant as heat and mass transfer medium. The heat and mass transfer between the fluid flows in the two towers has been modelled, and the energy saving potential in heating and cooling mode has been calculated based on annual hourly weather data. In order to assess the results, a comparison with the savings potential by sensible and total heat recovery have been performed considering 66 locations across Europe. Limitation and control strategies have been considered to prevent excessive indoor humidity considering different indoor latent load and airchange rates.