heating

As heat exchanges through building envelopes and undesirable internal gains have been reduced in the last years due to energy conservation efforts, the importance of the energy needed to heat, cool and move outdoor air for ventilation has increased in relative tem1s. This study, developed within the European project TIP-VENT (JOULE) aims to study the impact of ventilation air flow rates upon the energy needs of typical buildings. Five real buildings were selected as case-studies: A hotel, an auditorium, an office building, a single-family residence and an apartment building.

Nowadays the ventilated cooled beam is one of the most popular air-conditioning system, e.g. in Scandinavia and Central Europe. With such beams, it is possible to create high-quality indoor climate conditions, including thermal comfort and a low noise level within reasonable life-cycle costs. The beam is suitable for spaces with a high cooling requirement, low humidity load and relatively small ventilation requirement. Typically, the beams are used in offices and conference rooms.

The two-dimensional turbulent airflow generated by two non isothermal plane wall jets in a compartment is numerically investigated over a wide range of supply airflow rates. The low-Reynolds-number turbulence model of Nagano and Hishida, assembled in a finite-volume-based numerical code, is used after a previous validation study involving several other formulations of the k-e model.

Heat requirements of ventilation systems are becoming a dominant factor to be considered in energy balances prepared for residential buildings. This results from a consistent improvement of thermal insulating power and better tightness of partitions, as well as from the standards that ventilation systems have to meet in relation to the quality of the indoor air. This factor despite variable volumes of the air exchanged with the external environment, is not always considered in most estimates of thermal power quantities.

A house without a heating system in our cold climate - is it possible? In each of Goteborg, Malmo and possibly also in Hannover, about 20 terrace houses which are so energy efficient that they need no special system for heating are under construction. The Swedish Council for Building Research (BFR) is providing financial assistance.