The major objective of the IEA task XIII project is to design and construct low energy dwellings which should be technically and economically realistic in the period 2000-2010. The design criteria for the Belgian dwelling are the following: - low energy demand for heating purposes; - good thermal comfort conditions, as well in winter as in summer with attention to the problem of overheating; - very good airtightness (n50 <= 1 h^-1); - good indoor air quality conditions; - attractive design for majority of potential clients; - only use of realistic technical solutions.
This paper shows the extensive influence of humidity on comfort, cooling load and refrigeration capacity. Modern computer programs allow an effective consideration of humidity in systems.
A new ventilation and cooling system called OKOMAIR has been developed and investigated. The main idea is to separate carrying off cooling loads and providing fresh air to the occupants without mixing it with the return air. Return air is cooled by fan coil devices. The undiluted outside air is provided directly to the working zone and cooled by a cold waterstorage. This storage is charged by cool outside air during night. Use of the new system leads to high comfort for the occupants and reduces cooling energy.