As the sensible heat gain or cooling load are decreased by using thick thermal insulation in a building, the need for dehumidification increases. Especially in Kushiro, it is rather cool and humid in summer because of its foggy weather. In this study, two types of dehumidification systems were developed and their performances were examined. The first is a heat-recovery type, which uses a cooling coil and a sensible heat exchanger. The second is a moisture-absorbent type, which uses heating and cooling coils and an absorbent.
Although most new houses in the Hokuriku region are equipped with air conditioners, some people living in farmhouses still feel that cross ventilation is more desirable. Comparative measurements were made between a new house and a farmhouse. Simplified simulations were also carried out to clarify the effects of thermal insulation and earth floors on cross ventilation in summer. The role of thermal insulation in hot and humid regions is different from that in cold regions, where there is a large difference between outside and inside air temperatures.
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.
The paper presents some selected results of evaluation of improvement effectiveness of thermal insulation and tightness of multifamily dwelling houses located in the region of Silesia. The effect of the modernization work on heat consumption (to heat the buildings) and ventilation performance is discussed. Attention is paid mainly to the sensations of the flat users connected with air flows and change. Prospects of effective implementation of thermorenovation of buildings are evaluated in the conclusions when taking into account predominating role of ventilation.
In order to reduce the heat loss from buildings it is common to increase the thickness of insulation in the building envelope.The consequence of this action is more expensive buildings. Building regulations in countries with cold climate require U-values far the envelope which results in thicker and therefore often stronger constructions than needed for structural capacity. Another strategy to save energy has been to reduce the ventilation rates in buildings.
Since the cost of energy is increasing sharply a trend to conserve energy in the indoor environment and in addition to improvements in thermal insulation, two possible solutions are adopted. The first one is to provide reduced air gaps and opening for newly constructed buildings to minimise the infiltration of outdoor air. The second one is to reduce the ventilation rate or the fresh air supplied in air conditioned buildings. These two solutions are the reason for some serious problems of indoor air quality.
As part of a project financed by the National Foundation for Energy Research (NEFF), the Building Services Section at the EMPA examined the thermal behaviour of one building, with zero energy demands, located in a low energy housing estate in Waedenswil on the border of the lake of Zuerich. The estate was initiated by Dr. R. Kriesi who also made the energy concept. The architect was R. Fraefel and the estate was financed also by the government of Zuerich. The measures taken in order to reach a minimal heating demand in the chosen zero energy test house were as following:
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