In the mid-1980s, two London architects postulated that deflection of higher speed air from tall slab buildings could increase air infiltration from a neighbouring low-rise block, increasing its associated ventilation heat loss. These issues have been of much concern during the past two decades among designers, developers and local authorities; especially those considering in-fill near tall buildings. This preliminary study looks at the ventilation and space-heating loss of a three-storey low-rise office block located near a taller nine-storey slab building.
The paper presents a proposal of numerical procedure for air flow simulation in multi-zone buildings (up to 100 zones). This procedure can work with 1 hour time-step according torequirement of TRNSYS-a well-known modular system simulation programme. Co-operation between TRNSYS and my own programme is analysed, taking a typical Polish 5-storey dwelling house as an object of simulation. The proposed numerical procedure can also be run as an independent programme calculating the ventilation air flow, air change rate and heat losses due to infiltration.
Ventilation of buildings is necessary, both to insure adequate indoor air quality and to protect the building itself against condensation and mould growth. On the other hand, ventilation rates must not lead to excessive energy consumption. French regulation doesn't appreciate directly the indoor air quality but fixes requirements for the value of exhaust stale air in service rooms ; furthermore heat losses related to cross ventilation due to wind effects are also taken into account.
Increases in the levels of thermal insulation required in the walls and roofs of houses in the U.K. in recent years have meant that heat losses through floors now assume greater significance, as a proportion of the total heat loss from a dwelling. To effect further reductions in the energy consumption of houses, the thermal performance of floors needs to be examined to assess the most cost effective insulation strategy.
A combined thermal and ventilation model has been used to investigate the seasonal variation of air infiltration rates and ventilation heat losses in modern industrial buildings. The model was initially compared to measurements of ventilation rates, temperatures and heating loads in such a building, and was found to agree well. The model was then used to predict infiltration rates, temperatures, ventilation heat losses and space heating loads for a standard heating season for that building.
The continual reduction of the transmission heat losses of residential buildings causes an increasing importance of the ventilation heat losses. Energy saving can be achieved by using a mechanical ventilation system with heat recovery. A great improvement is the combination of heating and ventilation in one system. In this project such a combined system was developed to reduce the energy consumption of the fans, the operating expenses and also the investment costs in comparison to existing systems. In future a high market acceptance is expected for combined heating and ventilation systems.
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