An Experimental Study of Desiccant Wheel-Air Humidifier Integration in Hot and Dry Climates (original) (raw)
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The advantages of desiccant-based air conditioning systems, compared to conventional ones based on the dehumidification by cooling, have been highlighted in many research papers. The energy saving and the reduction of the environmental impact are higher when the desiccant material is regenerated by using ''free'' thermal energy (for example, waste heat from cogenerators or solar energy). Further investigation on the performance of the desiccant wheel is useful: therefore, in this paper, an experimental analysis on this component is presented, with particular attention to the variation of the performance as a function of the process and regeneration air flow rates. The desiccant material is regenerated by means of lowtemperature thermal energy (about 65°C) from a microcogenerator. Both the experimental results obtained by the authors and the data provided by the manufacturer have been used to calculate some performance parameters, and a satisfactory agreement has been obtained.
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Air-conditioning systems combined with rotary dehumidification were widely used in industrial buildings with low humidity requirements. In this paper, a rotary desiccant wheelbased hybrid air conditioning system with natural cold source was presented, which was used in civil buildings. In this system, sensible load was undertaken by the natural cool source, and latent load was undertaken by rotary dehumidification wheel. The performances of rotary desiccant wheel-based hybrid air conditioning system with natural cold source were studied in two typical outdoor meteorological conditions. The results showed that the system under both high temperature high humidity and high temperature low humidity conditions can satisfy the indoor environment demand for civil buildings, while the energy consumption on high temperature high humidity condition is less. While waste heat or solar energy is adopted as regeneration heat source, the energy consumption of rotary desiccant wheel-based hybrid ai...
An Evaporative Air Cooler and Desiccant Wheel Based Air Conditioning for Humid Regions of INDIA
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Nowadays, the increasing demand of summer cooling is typically covered by electric chillers, often determining electric peak loads and blackouts. Thus, a wide interest is spreading in small scale natural gas-fired cogenerators driving desiccant-based airconditioning systems, which represent interesting alternatives to conventional systems based on vapor compression cooling only. In this article, experimental tests performed on an air handling unit (AHU) equipped with a desiccant wheel (DW), coupled to a small scale cogenerator and an electric chiller are described. A new layout of the desiccantbased AHU is investigated, considering a third flow (the cooling air), besides the process air flow and the regeneration one. A cross-flow heat exchanger between process air and cooling air is used; the cooling air, cooled by an adiabatic humidifier, is aimed to precool the process air exiting the DW. The relevant influence of the heat exchanger and of the humidifier, as well as that of the chiller performance, on global primary energy requirements, water consumption and CO 2 equivalent emissions of the system is experimentally evaluated.
Performance Assessment of a Solid Desiccant Air Dehumidifier
Jurnal Teknologi, 2016
The presence of moisture in the air along with temperature has a long term and devastating effect on man and material. One way to create a low humidity environment is by using a solid desiccant wheel system. In the present work, an experimental analysis has been carried out under steady-state conditions to investigate the effects of different operating parameters on a solid desiccant wheel system performances. An experimental rig consists of an FFB300 air dehumidifier system was constructed. A parametric investigation was carried out to examine the effects of the reactivation air inlet temperature and process air outlet velocity on the thermal effectiveness, dehumidification efficiency, and moisture removal rate of the desiccant wheel system. The analysis shows that both thermal effectiveness and dehumidification efficiency decrease with the increase of the reactivation air inlet temperature, by 2.5 % and 43 %, respectively. Likewise, when the process air outlet velocity increases b...
Experimental Investigations on Liquid Desiccant Cooling Systems For Hot And Humid Climates
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Heat driven sorption technologies are promising alternatives to conventional vapor compression systems for cooling.Out of the various sorption technologies, desiccant systems are best suited for high latent load requirements andimproved indoor air quality (IAQ). Liquid desiccant systems are preferred over the solid ones due to the possibilities ofsimultaneous cooling during dehumidification, integration of solar collector with regenerator, easy storage of regenerateddesiccants. In this paper, the performance of liquid desiccant cooling systems for hot and humid climates is investigated.An experimental facility has been created to evaluate the performance of an indirect contact type liquid desiccant system.It consists of a dehumidifier, a regenerator and heat exchangers (solution-solution, air-water, and solution-water). Thedehumidifier and absorber used in the system are an indirect contact type of heat and mass exchanger known as Liquidto Air Membrane Energy Exchanger (LAMEE). This...
Heat and Mass Transfer between Humid Air and Desiccant Channels — A Theoretical Investigation
Due to the direct utilization of thermal energy and possibility of using renewable energy resources, the interest of using desiccant wheel for air conditioning application is increasing rapidly. The thermally driven desiccant cooling systems are environmental friendly and have a great potential to reduce the peak electricity demand. The high initial cost of these system as compared to the conventional units can be reduced at designing stage through selection of suitable cycle, size reduction, and flow optimization. The aim of this paper is to develop a mathematical model for the desiccant wheel to predict its dynamic performance. The model is numerically stable and easy to simulate. The desiccant wheel performance has been discussed under different operating parameters. The effect of mass flow rate on heat and mass transfer coefficient has also been studied. Results showed that, an optimum value of operating parameters like mass flow rate and regeneration temperature should be selected for better performance of the system. In addition, transient variation of vapor adsorption rate has also been discussed.