condensation

In recent years, earth-to-air heat exchanger (EAHE) systems, which is a method of pre-cooling and pre-heating outdoor air with earth-to-air heat, have been attracting attention as one of the technologies to achieve ZEB. However, at the operational phase, in order to achieve both energy saving and suppression of dew condensation control, EAHE control methods such as the timing or amount of outdoor air introduction have not been established.

Surface condensation risk is a fact that has to be dealt with when buildings are airtight. Airtight buildings with lower ventilation rates are the result of applying energy saving policies and criteria. Surface condensation risk depends greatly on the ventilation rates, as well as on another factors such as generation of water vapour, climate, envelope components and U value, etc.

Balanced ventilation with heat recovery is an efficient way to maintain low heating demand for ventilation in residential buildings. Laboratory measurements of today’s heat recovery ventilation units show high temperature recovery efficiency during standard conditions. In practice, however, the recovery efficiency may decrease due to circumstances that deviate from the standard laboratory conditions.

One of the problems presented by energy recovery ventilators (ERV) is the condensation/frosting problem that occurs during winter time. In order to prevent this problem, preheating outdoor air is the most common method used nowadays. The aim of this research is to evaluate preheat coil capacities according to different indoor/outdoor inlet air conditions (temperatures and humidities) and sensible/latent effectiveness of ERV (εS, εL).

Emergency Temporary Housing units consisting of a light-gauge steel brace construction were built following the Great East Japan Earthquake of March 11, 2011 (see Appendix). About 30,000 of these units are still in service following a delay in rehabilitation and reconstruction. The heat bridge portion in this kind of construction causes surface condensation in rooms. In addition, condensation damage on the steel roof surface in the attic space is also relatively large.

Interior-surface condensation on the glazed curtain wall of high-rise residential buildings is an important environmental issue in Korea. There are three causes of the surface condensation. One is the curtain wall frame materials, another is the generated moisture from residents' behaviors such as cooking and drying the laundry, the other is inadequate ventilation caused by stack effect.

Even in relatively warm area in Japan, frost damage of roof tiles occurs. In this study, the influences of several factors on frost damage are considered from a thermal environmental point of view. Condensation on the external surfaces of roof tiles, which is caused by a temperature drop due to nocturnal radiation, is estimated as one of the most important factors to the frost damage. The frequency of condensation was calculated by a numerical analysis. The influence of the parameters, such as the inclination angle and the orientation of the roof, is investigated.

The National Museum of Western Art is the only work of Le Corbusier in Japan and 50 years have already passed since its construction. In order to maintain the museum’s value as a cultural asset, there is an urgent need to draft a thorough retrofit plan both to maintain the building’s function as an art museum and to restore Le Corbusier’s original design concept.

It is not unusual to face moisture problems in buildings in cold climates and wet regions. It is, however, unusual to have the same problem in a relatively dry region such as Jordon, which has moderate weather conditions and mild winters. Nevertheless, a significant proportion of houses and residential apartments in Jordan are affected. The monitoring of inside air conditions, wall surface temperatures, ventilation and living style has shown that a high relative humidity (RH >75%) occurs at walls resulting in possible condensation.

Ventilation radiators, heat emitters where cold ventilation air is brought directly from outdoors into theroom via heated radiator surfaces, are becoming more and more common in Scandinavia. Becausethese systems combine both heating and ventilation several interesting aspects arise that may be usedto save energy and improve indoor thermal climate. The heating aspects in wintertime have beendiscussed in previous papers from KTH STH.