humidification

In reaction to the European Energy Performance of Buildings Directive (EPBD), existing and newly lanced standard developments by CEN (European Committee for Standardization) were harmonized and synchronized, resulting in a set of about 50 standards addressing different aspects of the EPBD and the implementation of an overall building energy performance calculation method. A few of them address simulation issues: An overview of these is given, focusing on one standard covering system related aspects for buildings with cooling, humidification or dehumidification.

In reaction to the European Energy Performance of Buildings Directive (EPBD), existing and newlylanced standard developments by CEN (European Committee for Standardization) were harmonizedand synchronized, resulting in a set of about 50 standards addressing different aspects of the EPBDand the implementation of an overall building energy performance calculation method. A few of themaddress simulation issues:An overview of these is given, focusing on one standard covering system related aspects for buildingswith cooling, humidification or dehumidification.

Until the end of 90-ties all dwelling buildings in Latvia were equipped with mandatory natural ventilationsystems with stack effect. Nowadays in many cases in dwellings there are only exhaust mechanicalventilation but air tight windows prevent natural air intake. Such systems result in bad IAQ.

In this paper the performance of a desiccant cooling system was evaluated. The system comprises a desiccant wheel in tandem with a thermal wheel with evaporative coolers in both air supply and return air streams before the thermal wheel. It allows cooling and dehumidifying air without using conventional refrigerants. A computer simulation was developed to study the effects of various designs and outdoor air conditions on the performance of the system. The simulations were run with SPARK, an object oriented program that allows creation of very flexible tools.

An evaluation of the effect of air humidification on various factors was performed, including skin dryness and mucosa, allergic and asthmatic reactions and perception of IAQ. A six period cross over trial was conducted on 290 office workers. A total of 211 workers who returned at least two weekly diaries and who had experienced both humidified and nonhumidified conditions were included in the analyses. The main outcome was characterized by dryness, irritation or itching of skin and eyes, of the throat and nasal dryness.

Describes a study of air humidification in the Pasila Office Center, which is a modern eight-floor office buildings of 2150 workers in Helsinki, Finland. A comparison was done between the occurrence of symptoms and complaints among the workers in the humidified part of the building and the symptoms and complaints of workers in similar nonhumidified rooms during February, March and April. Significantly less dryness of skin, throat and nose and nasal obstruction as well as sensation of air dryness was reported by the workers in the humidified part.

The aim of the study was to evaluate the effect of humidification on the odour, acceptability and stuffiness of indoor air. The air of two wings of an office building in turn were ventilated with air of 30%-40% humidity in a six period cross over trial. The third wing was used as a non-humidified control. A panel assessed the quality of indoor air weekly. Mean intraindividual differences were used to assess the roles of sex, current smoking and age. The study found that humidified air was regarded as more odorous and stuffy than non-humidified air.

In the study a collection was made of bacterial and fungal spore samples from twelve office building ventilation systems. Measurements were performed with and without humidification. In none of the cases were ventilation or humidification systems found to act as bioaerosol sources. There was no observed difference between bioaerosol counts in offices with and without humidification. In all ventilation systems the microbial levels decreased.

The study collected water samples from 33 of 54 HVAC humidification system water reservoir pans in a large office building. The nature of the contamination that was found indicated that cleaning was ineffective, and may increase the risk of biological contamination. Of the two different humidification systems, air wash and steam injection, the air wash system revealed high contamination of samples.