Potential of heat and moisture recovery for future reduction of dehumidification and humidification deams in Swiss office buildings

HSLU Lucerne University of Applied Sciences and Arts, Engineering and Architecture, 6048 Horw, Switzerland

^* Corresponding author: simone.dugaria@hslu.ch

Abstract

Future climate scenarios show that temperatures in Europe will rise in the coming decades. It is expected that dew point temperatures will rise as well. This will be linked to an increasing feeling of sultriness, which will trigger a higher need for dehumidification to meet comfort requirements. New European standards offer the possibility of choosing between different indoor qualities (categories) for indoor humidity. In addition, there are efforts that call to increase the minimum indoor relative humidity to 40 %. This will imply a possible increase in the need to humidify the indoor air, especially in the winter period. Air-to-air enthalpy exchanger with combined humidity and heat recovery have the potential to reduce the dehumidification and humification need. Multi-zone dynamic simulations were carried out to assess the near future (2035) and around mid-century (2060) dehumidification and humification need and associated peak power and energy demands in a typical office building with mechanical ventilation under different boundary conditions in Switzerland. The results show that the adoption of enthalpy recovery as a replacement for sensible heat recovery brings significant benefit in winter, as it reduces the humidification need and the related power of the humidifier and preheater. In the summer period, there is only a reduction in the dehumidification need and associated power in the more humid and warmer Swiss climate, while in the colder climate the humidity-based control logic leads to counterproductive effects for the space cooling.