To increase of diffusion on the bioclimatic architecture is necessary to make the calculation Method easy to use for designers. In particular the available calculation method for analytical, based on transfer functions or finite elements method or those made for simplified calculations are generally very complex to use. Is necessary to develop methods of analytical type and simplified more "friendly" to use.
The paper describes a method to calculate the heat flow through a multiple layer wall in a natural climate. The thermal properties needed for the calculation are the thermal resistance and the heat capacity of each layer, and they are assumed to be independent of the temperature. The natural climate can be measured temperatures, either surface temperatures or temperatures of the surrounding air. The method is based on well-known equations for calculating the heat flow due to a sinusoidal temperature variation.
Existing infiltration and exfiltration calculation methods are mainly based on the stationaryapproach, where long term mean values are used for wind input data. The real wind speed is,however, varying continuously with time. Because the process of the crack flow is non-linear,using mean wind speed values will give erroneous results for the air flows.
Thick insulation in buildings offers great potential not only for decreasing cooling load but also for changing its calculation method, and for changing system design, operation or control of the system and the thermal environment of the room. The research results of room air temperature changes in well-insulated buildings, show the effects of the daily swing of outdoor temperature and solar radiation are quite small. A simple calculation method for cooling load based on steady state theories is available for such buildings.
Computer programs for the calculation of non-isothermal air flow in rooms have been developed in the last years as reasonable precise and effective tools for non-conventional and difficult tasks in air conditioning technology. This paper shows possibilities based on the additional numerical calculation of the convective mass transfer. Several simple examples describe the influence of the hood and the room air flow on the convective heat and mass transfer. Based on this knowledge the optimal arrangement of the hoods, the air outlets and the air inlets can be determined.
We present a simple model to calculate the energy loss by free cooling at night. The time dependence of the exhaust air and wall surface temperatures is predicted by a simplified dynamic model that couples air flow, heat transfer, and wall temperature. For given ventilation rate the model predicts that the total heat extracted from the building during the night can be maximized by increasing the heat exchanging surface area and the thermal effusivity, of the wall materials. The influence of ventilation rate on the heat removed by freecooling at night is discussed.
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