Today, tracer gas is used as a reliable means to examine various queries related to mechanical systems. Prerequisite is the safe and routine handling of the relevant analysis methods. Apart from some basic considerations, the present paper includes results of ventilation efficiency studies and a comparison of different systems on the basis of characteristic parameters.
Air-conditioning and ventilation systems, which help to maintain the indoor environment ofbuildings, account for more than half of the energy consumed in them. While it is necessary toimprove the energy efficiency of buildings due to economic and environmental reasons, it isimportant to do so without compromising their indoor environment. Various optimizingstrategies for air-conditioning and ventilation systems that help to improve energy efficiencywhile enhancing the quality of the indoor environment of buildings are described in this paper.
Energy efficient operation of variable speed fans in Variable Air Volume (VAV) systems ishighly dependent on both the type of duct design as well as the type of control strategy thathas been implemented in association with the volume flow demand profiles of each individualzone in the building. The quantification of energy savings due to duct design and the effects offan control have generally been poorly understood, even with very simplistic types of controlstrategies, e.g. static pressure P + I control which have often been employed.
Earlier studies have shown that airflows are not well balanced in office buildings. This maylead to too low ventilation rates in some rooms and too high ventilation rates in others.Several studies have shown that low ventilation rates may lead to a higher prevalence of SBSsymptoms. The reduction of these symptoms may be achieved with improved ventilation.The purpose of this study was to evaluate the benefits of balancing the airflows of the airdistribution system of an office building in Helsinki.
In order to effectively control nosocomial infection 12 respiratory isolation rooms fortuberculosis patients in four hospitals have been built by the Energy & Resources Laboratories,Industry Technology Research Institute in Taiwan. This project was funded by the Center ofDisease Control of the Health Department. The performance of the air-conditioning andventilation/exhaust system of respiratory isolation rooms has been tested and validated. Thetested items include ventilation rate, static pressure, temperature, humidity and noise.
This paper proposes a new mode of ventilation for indoor airflow. It uses a plate or a curvedvane to divert a jet of air directly into the breathing zone. Computational results show that withproperly selected diffuser locations and design air supply velocities, the proposed systemwould be able to maintain better thermal comfort with a smaller temperature differencebetween the head and foot level, and possibly lower energy consumption, when compared withconventional systems.
Split system air-conditioning units are commonly employed in residential buildings inthe tropics due to their convenience in terms of energy conservation, aesthetics,flexibility, acoustic performance and ease of operation. This paper presents ourfindings from a recent study of the IAQ and ventilation characteristics in a masterbed-room of a condominium unit in Singapore, employed with a split system airconditioningunit. The attached bathroom is equipped with an exhaust fan, whoseoperation and its impact on the resulting IAQ and ventilation characteristics was alsostudied.
The performance of a Personalized Ventilation (PV) system with regard to air qualityperceived by people was studied at three room temperature levels: 23, 26 and 29C. Thirtyhuman subjects participated in the experiment. The system supplied both isothermal (23, 26,29C) and non-isothermal (23C) outdoor air from an outlet attached to a moveable arm. Thesubjects were delegated with control of both airflow velocity and its direction. Physicalmeasurements performed with a breathing thermal manikin were used to explain the resultsfrom the human subject experiments.
One of the most common measures of IAQ (indoor air quality) is carbon dioxide, CO2, generated by human respiration, in particular, where the main source of pollutions are occupants. In this report, the occupancy-related pollutants are considered as the main pollutant source. However, other type of sources may also be removed satisfactory when governing the ventilation system for removal of
The visual evaluation method has been created for a primary method to verify cleanliness ofHVAC system. The results of two simple measuring methods for thickness of dust and debriswere compared to accumulation values measured by vacuum sampling method. The thicknessof dust layer and the dust accumulation results correlated when the dust was homogeneousbut the correlation was poor if the quality of the dust varied. Both the field and laboratorystudies showed that a commercial contact method gave lower microbial counts than the swabmethod with cultivation.
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