Rotary heat exchanger model for control and energy calculations

Rotary heat recovery exchangers are widely used in ventilation systems, and the units are known for their high efficiency and almost maintenance-free operation. Temperature efficiencies above 80% are not uncommon. Performing dynamical analyses of rotary heat exchangers are in many situations advantageous, especially in connection to installation of such equipment in VAV systems. Efficiencies and flows are varying parameters that are crucial for energy calculations, but also for control. The dynamical analysis can effectively be carried out by addressing a dynamical model.

A study on eco friendly furniture for mitigation of the indoor air pollution

Furniture can raise indoor air contaminants with toxic emissions of VOC and formaldehyde.. While furniture is classified as a subject of safety and has quality labeling, there is a lack of domestic regulations related to contaminant emissions with the exception of sinks. When looking at the analysis on environment-related patients related to the smell or odors from furniture every year, patients suffering from asthma, allergic rhinitis, and atopic dermatitis are on the rise.

A Study on Indoor Environments Made by Thin Line Type Ventilators in Apartment Houses

Total heat recovery type ventilators that are connected to each room with ducts are mainly installed in Korea, but they raise concern over duct pollution. In this study, indoor environments made by thin line type ventilators installed in dwelling units of apartment houses are investigated by CFD. Results show the case that thin line type ventilators installed in each room - including kitchens - make the best indoor environment that maintains air velocity at under 0.25m/s, and evenly distributes the age of air in all areas.

Numerical prediction of particle transport passed through ventilator by CFD with Lagrangian method

The use of CFD technique for predicting the properties of airflow fields and particle movement is effective to carry out parametric study intended for a wide range of particle sizes. In this study, particle dispersions due to turbulent flow and thermophoretic effect were analyzed for a simplified ventilator model. Numerical results that comprise a classification of particle motion, temperature difference and particle diameter were reported.

Distribution of CO in 30 Homes with Unvented Gas Fireplaces

As part of a field measurement project of unvented gas fireplaces in 30 homes, portable carbon monoxide sensors were located in several places in each home. This was done to assess the degree to which combustion by-products became distributed throughout the home. The sensors indicated that carbon monoxide levels began rising throughout the home almost immediately, at or near the one-minute sampling interval. The results show that, on average, the reading in the middle of the fireplace room was about 95% of the reading at the mantel.

Experimental method for determining removal efficiency of house dust by mechanical ventilation

Biological contamination has recently become an important issue in the residential indoor environment. In fact, one of the leading causes of allergic diseases is the presence of mold and mites in house dust that accumulates on the floors, near the breathing zone for infants and toddlers. In this research, experimental studies were carried out in order to examine particle removal efficiency in a room with two ventilation systems: a ceiling exhaust system and a slit exhaust system.

Health Hazards in Indoor Air

Indentifying pollutants that pose a potential hazard indoors is an important first step to reducing risks. We reviewed key published studies reporting measurements of chemical pollutants in residences. Summary results were compiled and used to calculate representative mid-range and upper-bound concentrations relevant to chronic exposures for over 300 pollutants and peak concentrations relevant to acute exposures for a few episodic activity-associated pollutants.

Exposure Risk Assessment by Coupled Analysis of CFD and SIR model in Enclosed Space

The indoor environment can play a significant role in the transmission and exposure of various contaminants. In some emerging aerial infections, such as influenza virus, tuberculosis virus, and other biological and chemical contaminants, the airborne route of transmission is thought to be important to evaluate exposure health risk.

Numerical Prediction of Airflow and Temperature Distribution in Large-Scale Agricultural PVC Greenhouse

Large-scale greenhouses are usually adopted to control the indoor climate conditions in agriculture. The envelope of agricultural greenhouses generally consists of a PVC (polyvinyl chloride) sheet, which produces a so-called greenhouse effect and protection from harmful insects. In winter, a supplementary heating device in greenhouses is needed because of the lower outdoor temperature and the non-uniform distribution of indoor temperature.

Year-round Energy Saving Potential for a Stratum Ventilated Subtropical Office

Stratum ventilation has been proposed to cope for elevated indoor temperature recommended by governments in East Asia. TRNSYS is used for computation of the space cooling load and system energy consumption. A typical Hong Kong office is investigated. Compared with mixing ventilation and displacement ventilation, stratum ventilation derives its energy saving potential largely from the following two factors: a reduced ventilation load and increased coefficients of performance (COP) for chillers.