Independent Air-conditioning System Research Articles

Effects of suspension of air-conditioning on airtight-type racks.

Although isolation racks are superior to open-type racks in terms of securing breeding conditions for laboratory animals, the contingency-proofing capability of the former has yet to be determined. Therefore, from the view of risk management, we studied the environmental change in isolation racks by forcibly suspending ventilation and air-conditioning and confirming the maximal time length for complete recovery to the original condition after restarting their operations. The isolation racks were placed in a room that was equipped with an independent air-conditioning system. When the inside condition of the racks reached 22-24 degrees C and 59-64% of relative humidity, the air-conditioning and ventilation were forcibly suspended and the subsequent temperature, relative humidity, ammonium and CO2 concentrations in the racks were measured over time. We found that after suspending the air-conditioning and ventilation, it took 40-60 min for temperature, and about 10 min for relative humidity to exceed the maximum values (temperature and relative humidity) referred to in the Showa 58 Nenban Guideline Jikken Doubutsu Shisetsu no Kenchiku oyobi Setsubi (Guidelines of buildings and facilities for experimental animals in Japan; Year 1983 edition). After 17 hr 25 min of the suspension of air-conditioning and ventilation, two rats were found dead. Then, the air-conditioning and ventilation were restarted. It took about 2 hr for temperature, and 50 min for relative humidity to regain the guideline values. The ammonium concentration stayed within the guideline value with a maximum concentration of 2 ppm in the experimental period, whereas the CO2 concentration was found to exceed 9% at the time of animal death.

ＣＯ２削減コストより見たごみ発電廃熱 地域冷暖房の導入可能性評価

This study was conducted to clarify the capabilities of introducing a district cooling and heating system using the waste heat from the power generated by garbage incineration into the urban energy system.This system was compared with an independent air conditioning system and a dis-trict cooling and heating system using city gas.The results show the use of garbage generated waste heat to be highest in equipment costs and lowest in energy consumption among the three above-mentioned systems. The total costs of equipment plus energy vary with the volume of heat demand and the distances from the heat source to the demand sites.Consequently in the district cooling and heating system, the substitution of waste heat from the power generated by garbage incineration for city gas can reduce CO2 emissions at the cost of 15, 000yen/ton-CO2. This is dependent upon the distances between heat source and heat demand site being from 2-8km, with daily heat demands being 500-5, 000GJ/d for the respective distances from heat sources.

Preprocessing cotton to prevent byssinosis

<b>Merchant, J. A., Lumsden, J. C., Kilburn, K. H., Germino, V. H., Hamilton, J. D., Lynn, W. S., Byrd, H., and Baucom, D. (1973).</b><i>British Journal of Industrial Medicine,</i><b>30,</b> 237-247. <b>Preprocessing cotton to prevent byssinosis.</b> A fundamental approach of cleaning or deactivating cotton prior to manufacturing has long been advocated to prevent byssinosis, but no trial had been conducted to test the feasibility of such an approach. In the study described, it was possible to be directed by both biological observations and the results of manufacturing trials. An exposure chamber was built in a cotton textile mill which had been previously studied as part of a large cross-sectional survey. The chamber was provided with an independent air conditioning system and a carding machine which served as a dust generator. Sixteen subjects, who had shown reductions in expiratory flow rate with exposure to cotton dust, were chosen to form a panel for exposure to raw cottons and cottons which had been preprocessed by heating, washing, and steaming. Indicators of effects were symptoms of chest tightness and/or dyspnoea, change in FEV_1·0, and fine dust levels over 6 hours of exposure. Exposure of the panel to no cotton dust resulted in no change in FEV_1·0 and served as the control for subsequent trials. Exposure to strict middling cotton resulted in a byssinosis symptom prevalence of 22%, a significant decrement in FEV_1·0 of 2·9%, and a fine dust level of 0·26 mg/m³. Exposure to strict low middling cotton resulted in a byssinosis symptom prevalence of 79%, a decrement in FEV_1·0 of 8·5%, and a fine dust level of 0·89 mg/m³. Oven heating strict low middling cotton resulted in a byssinosis symptom prevalence of 56% and a relatively greater drop in FEV_1·0 of 8·3% for 0·48 mg/m³ of fine dust. Washing the strict low grade cotton eliminated detectable biological effects with a symptom prevalence of 8%, an increase of 1·4% in FEV_1·, and a dust level of 0·16 mg/m³, but the cotton proved to be difficult to process. As an alternative method, strict low middling cotton was steamed initially in large dyeing vats, on a conveyor, in an autoclave, and in a modified yarn dyeing apparatus or `pipe9 steamer. Of these methods, autoclaving cotton was the most successful, reducing symptom prevalence to 8%, the drop in FEV<sub>1·0</sub> to 0·4%, and the dust level to 0·23 mg/m<sup>3</sup>. Development of a high capacity cotton steamer based on the small `pipe9 steaming model resulted in a symptom prevalence of 8%, a decrement in FEV_1·0 of 0·8%, and a mean dust level of 0·27 mg/m³. Regressions calculated from raw and high capacity steaming trials indicate that at low dust levels steamed cotton dust was roughly one half as biologically active as raw cotton dust.