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Desiccant Dehumidification Technologies
Published in Neil Petchers, Combined Heating, Cooling & Power Handbook: Technologies & Applications, 2020
In the sorption process, the removal of moisture from the air results in a release of heat (heat of sorption) that raises the air temperature as the process converts latent cooling load to sensible cooling load. Figure 39-4 shows three sensible cooling options that can be incorporated in desiccant systems to provide sensible cooling. The recuperative heat exchanger transfers heat to the air used to regenerate the desiccant. This can be supplemented by or replaced with a conventional chiller. The direct evaporative cooler evaporates water into the warm, dry air to cool it. Usually, this process cannot provide the full measure of required sensible cooling. The indirect evaporative cooler evaporatively cools a separate airstream and uses it to cool the dry air through an air-to-air heat exchanger.
Gas Turbine Inlet Treatment
Published in Tony Giampaolo, Gas Turbine Handbook: Principles and Practice, 2020
The evaporative cooler is a cost-effective way to recover capacity during periods of high temperature and low or moderate relative humidity. The biggest gains are realized in hot, low humidity climates. However, evaporative cooler effectiveness is limited to ambient temperatures of 50°F (10°C) to 60°F (16°C) and above. Below these temperatures, parameters other than turbine temperature will limit gas turbine operation. Also, as the inlet air temperature drops the potential for ice formation in the wet inlet increases.
Dry Scrubbers for the Control of Air Toxics
Published in Howard E. Hesketh, Frank L. Cross, Sizing and Selecting Air Pollution Control Systems, 2020
Different flue gas cooling techniques that can be used are noted in Table 7.2 and are discussed here. Boiler: A heat recovery boiler recovers heat by converting water to steam which can be used for plant requirements and/or sold to a nearby user. Corrosion is the greatest danger to a boiler system, and to avoid problems, the exit temperatures are not always brought as low as necessary; and a secondary gas cooling device is required.Evaporative Cooler: An evaporative or quench cooler reduces the temperature by the direct evaporation of water in the gas stream. This type system offers advantages in that the gas is cooled very quickly, which avoids the formation of dioxins. Evaporative cooling is an integral part of the spray dryer acid gas scrubbing system, and often evaporative cooling and spray drying are integrated into a single system.
Levels of formaldehyde in residential indoor air of Gonabad, Iran
Published in Human and Ecological Risk Assessment: An International Journal, 2020
Mohammad Hadi Dehghani, Ahmad Zarei, Mansoureh Farhang, Prashant Kumar, Mahmood Yousefi, Ki-Hyun Kim
Most of the available products and building materials inside the homes in the present study were manufactured from wood-based materials. Therefore, the wood-based products are expected to be the main contributors to the FA budget at each room. Significant emissions could be due to the use of FA-based resins in the manufacture of these materials (Rezaei et al.2015). In arid places of Iran, evaporative coolers are extensively used in almost all houses and departments, especially in dry regions. The evaporative cooler has the benefit of conditioning the air with more moisture for the comfort of occupants in the building. Most of the rooms were equipped with evaporative coolers. On very hot days, most occupants will try to restrict indoor air exchange with outdoor air to improve comfort and energy efficiency during the use of coolers, leading to increased relative humidity and pollutant concentrations inside the indoor environments. The average relative humidity inside the studied rooms was 50.4%. A positive correlation between levels of FA and temperature was observed in this study. This result is consistent with the results obtained from temporary housing units (THUs) in the United States (Parthasarathy et al.2011). In this study, FA was not measured in the air outside the homes. However, their presence in outdoor air is thought to have little influence on indoor levels (Jurvelin et al.2001).
Evaluation of desiccant wheel and prime mover as combined cooling, heating, and power system
Published in International Journal of Green Energy, 2019
M. Mohammadian Korouyeh, M. H. Saidi, M. Najafi, C. Aghanajafi
Kodama et al. (2001) evaluated desiccant wheels and studied rotational speed effects on the outlet air properties. They evaluated the change of state of product air with increasing the rotational speed. Esfandiari Nia, Van Paassen, and Saidi (2006) investigated mass and energy equations inside the desiccant wheels and suggested a model to predict the state of product air in the function of wheel technical specification and also inlet air properties. Zadpoor and Golshan (2006) studied desiccant wheel effects on air properties of inlet air to the gas turbine and the turbine performance. They showed that combination of the desiccant wheel and evaporative cooler may be effective in hot and humid locations. Hammoud, Ghali, and Ghaddar (2014) studied the performance of displacement ventilation aided with personalized evaporative cooler and used solid desiccant dehumidification system that was regenerated by solar energy. They showed that hybrid system can achieve 13.5% energy saving compared to a reference conventional system including a chiller and a reheater. Saidi, Aghanajafi, and Mohammadian (2010) studied desiccant wheel effect on performance of a wet cooling tower. They evaluated the effect of desiccant wheel parameters on the exiting cooling water of a cooling tower. Fong and Lee (2018) studied a desiccant cooling system which includes a desiccant wheel, a sensible heat exchanger, a regenerative coil and an evaporative cooler in hot and humid regions. They evaluated regeneration heat effects on the system performance and found that the required regeneration temperature should be higher than 60 C.