This paper is a report on humidity control in schools mainly located in hot and humid climates : according to the US Department of Energy's investigation, most of them, use packaged cooling equipments that are not able to manage space humidity effectively when delivering a high percentage of outdoor air. Those schools don't respect the requirements of the ANSI/ASHRAE standard 62-1999.
By using the dedicated outdoor system (DOAS) approach, ventilation effectiveness and humidity control can be improved and meet the recommendations of the ASHRAE 62-1999 standard.
Purpose of this study is establishment of energy efficient natural ventilation system for Japanese conventional wooden single-family house, by using humidity-controlled extract units (code name: GHN).To evaluate the effect on energy performance and indoor air quality by adapting the GHN to the passive stack ventilation system, airflow rate, humidity, temperature and CO2 concentration are measured over a period of one year in an experimental house.
A condensing device allows to avoid condensation on cooling ceilings in rooms with humid air. It uses thermoelectric modules in contact with the cooling panels. The pumped heat is transferred into the cooling ceiling to keep its temperature above the dew point. Tests have been performed in a full-scale chamber. A set of condensing units was mounted on a standard hydraulic cooling ceiling. The control of temperature is achieved by regulating the mass flow of the water. By this method the loss of efficiency of the cooling panels is fully compensated.
This paper deals first with experimental measurement performed in a test chamber to investigate the characteristics of temperature and moisture distributions. The effect of moisture accumulation in building material is studied too. Then a new approach is introduced to describe the simultaneous heat and moisture transfer. The results has been compared with a CFD model.
The environment inside museums such as the Field Museum of Natural History in Chicago, USA is of utmost importance since permanent damage can be caused to artifacts in the environment is not correctly maintained and controlled. The article describes a longitudinal environmental survey carried out to assess the performance of the facility's HVAC systems and controls. A series of hypotheses was developed and tested to explain deterioration of a number of mammal mounts in the museum's exhibition halls.
Mechanical ventilation with heat recovery (MVHR) and passive stack ventilation (PSV) systems are both proposed as methods of ensuring satisfactory ventilation rates in UK housing. MVHR provides controlled ventilation in all rooms together with heat recovery, while the cheaper PSV system offers lower running costs, but without heat recovery and without a controlled air supply to all rooms. The relative energy consumption of the two systems depends on a number of factors that are difficult to predict.
The knowledge of IEA-Annex 14 'Condensation and Energy' has been applied to develop a new strategy for humidity control in dwellings. The presented control element assures safe prevention from mould growth at a minimum energy consumption. The advanced humidity control device consists of a surface temperature and an indoor air temperature sensor, from which readings a microcontroller evaluates the appropriate RH setpoint. A humidity sensor then reads the actual RH in the room air and compares it with the momentary setpoint.
In the framework of a CEC-DGXVII demonstration project a hygroregulating natural ventilation system is being evaluated in 52 occupied apartments. Therefore a multi purpose automated tracer gas equipment has been developed enabling the detailed monitoring of air flow rates in 60 rooms continuously. In addition the humidity levels, CO2 levels and air temperatures are measured as well as the outdoor climate. The first measurement campaigns partly used for evaluation of the measurement system are reported and show an impressive amount of data enabling various types of detailed analysis.
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