This present work has theoretically investigated coupled heat and mass exchangemechanisms in counterflow rotary dehumidifier with the mixed desiccant of LiCl and additives,used in air conditioning systems. Mathematical model has been derived, based on one-dimensionaltransfer model and Polyni potential theory (theory of water chemical potential)and solved, using digital computer. The profiles of temperature and absolute humidity distributionin the matrix have been obtained. Analysis shows, that the direction of mass transfer isopposite to positive water vapour partial pressure.
A humidity controlled air flow terminal device works as a humidity sensor : its openingsurface varies according to relative humidity inside a room in order to match air flow rate topollution. These components are fouling up when used during several months.In a laboratory, an air flow with a high rate of particules is fouling up five identical air devicesin a few hours. Considering a constant relative humidity, the impacts on two devices aresimilar : it seems that artificial fouling tests can be reproduced.
The inadequate dissipation of hurnidity fiom living spaces and bathrooms has become asignificant problem area in recent years. This can be attributed both to the replacement of old,poorly sealed windows by new windows with better seals, and to the increasing use of tilesand other building materials which hinder an adequate absorption of water vapour.The residents tend to reject repeated opening of the windows for ventilation purposes ongrounds of the ensuing energy costs.
The traditional way to dehumidify the outdoor air in a heating, ventilating and airconditioning (ENAC) system is by cooling the air temperature down below the dew point.For this process a refrigeration system is necessary to realise these low temperatures.Nowadays the disadvantages of refrigeration systems are widely known. An alternativemethod to dehumidify the air is by separating the process of dehumidification and cooling.There are different ways to get low supply air temperatures for cooling the indoor spaces.
Continuously rising energy costs, the demand for reduction of CO2-emission and theprohibition of CFC-containing refrigerants create a base for new concepts of air-conditioning(A/C) systems. A primary action must be the prevention of heat consumption and cooling loadby improvement of the building architecture. Additional the efficiency of the A/C process mustbe improved, in order to reduce the energy input.In most cases the target is to replace the dehumidification process, which normally is realizedby refrigerating cycles, by alternative systems.
As the sensible heat gain or cooling load are decreased by using thick thermal insulation in a building, the need for dehumidification increases. Especially in Kushiro, it is rather cool and humid in summer because of its foggy weather. In this study, two types of dehumidification systems were developed and their performances were examined. The first is a heat-recovery type, which uses a cooling coil and a sensible heat exchanger. The second is a moisture-absorbent type, which uses heating and cooling coils and an absorbent.
The main source of humidity in office buildings is the human occupant. Moisture is therefore a result of heat transmission from the person to the room air. The article covers heat transmission of the human body, humidity and comfort, cooling and dehumidification, and refrigeration capacity.
The purpose of this paper is to present the energy required to condition a constant volumetric airflow and determine the variability of this energy due to changes in the design dry bulb and humidity setpoints. Hourly weather data from a typical year from 32 European locations and long-term data from 11 American locations were analyzed to determine the coincident dry-bulb and dew-point temperatures. These data were then analyzed to determine the heating, cooling and moisture removal energy requirements for a constant mass of airflow per hour.
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