Major Parameters Affecting Temperature inside Inhalation Chambers

摘要

These studies showed that stainless steel chamber walls were very effective at removing heat from an (380 l) inhalation chamber. Cooling the incoming air was not as effective in cooling the stainless steel chamber, because most of the heat transfer from the animals in the chamber was by thermal radiation and the cooled intake air was rapidly heated through the chamber wall by the surrounding room environment. With the chamber air supply at room temperature, heat transfer through noninsulated stainless steel walls was effective in removing approx. 90% of the heat generated by the animals as compared to only 10% removed by the airstream at 100 l/min. It is important that design engineers be aware of the relatively large percentage of cooling that takes place as the result of heat transfer to and from the chamber surfaces. With low flow rates, the heat transfer to the surrounding environment can be increased when necessary by painting the chambers (independent of color), thereby maximizing the emissivity of the stainless steel, by attaching cooling fins or cooling coils to the chamber walls, or by directing the room air conditioning ducts directly onto the chamber. In situations where suitably higher amounts of toxin can be used, the airflow through the chamber can be increased to augment removal of the heat generated by the animals. This study also indicated that by measuring an effective heat transfer coefficient for a chamber one can determine for specific flow rates the maximum room temperature permissible to maintain a reasonable chamber temperature with varying animal loadings. (ERA citation 06:009761)