Demand controlled hybrid ventilation for cold climates

The aim of the project is to study, develop, build (prototype system) and evaluate an energy efficient demand controlled hybrid ventilation system for dwellings in a cold climate. Hybrid ventilation in a cold climate means a ventilation system with low pressure drops, which result in a minimisation of the mechanical energy for ventilation, and that natural driving forces can play an important role. The project is included in the EC research project Reshyvent Cluster Project on Demand Controlled Hybrid Ventilation in Residential Buildings with specific emphasis on the Integration of Renewables. Demand controlled hybrid ventilation is considered to be a promising system of ventilation for the future, where stringent requirements as to energy efficiency and air quality are to be fulfilled. The ventilation concept is based on an exhaust air system with low pressures drops and a separate fan for each apartment. The fan has a built-in control system for a, according to desire adjustable, constant exhaust air flow independent of the boundary conditions. The desired air flow can be set from a panel in the apartment, but is also automatically controlled by humidity and outdoor air temperature. The outdoor air is preheated by a supply convector. Each apartment has individual control of indoor climate and individual metering of energy use. The system will result in a similar level of energy use for space heating as for a system with balanced ventilation with traditional heat recovery, but lower use of electricity, more user-friendly and improved indoor air quality.