Search results for "Evaporative cooler"
showing 10 items of 13 documents
Orographic Effects and Evaporative Cooling along a Subtropical Cold Front: The Case of the Spectacular Saharan Dust Outbreak of March 2004
2012
Abstract On 2 March 2004 a marked upper-level trough and an associated surface cold front penetrated into the Sahara. High winds along and behind this frontal system led to an extraordinary, large-scale, and long-lived dust outbreak, accompanied by significant precipitation over parts of Algeria, Tunisia, and Libya. This paper uses sensitivity simulations with the limited-area model developed by the Consortium for Small-Scale Modeling (COSMO) together with analysis data and surface observations to test several hypotheses on the dynamics of this case proposed in previous work. It is demonstrated that air over central Algeria is cooled by evaporation of frontal precipitation, substantially en…
Energy performance evaluation of a demo solar desiccant cooling system with heat recovery for the regeneration of the adsorption material
2012
Abstract Since July 2008, a Solar Desiccant Evaporative Cooling (DEC) system has been operating as a test plant at the solar laboratory of the Dipartimento di Energia (ex DREAM) of the University of Palermo. The system is composed of an air handling unit (AHU) designed for ventilation of the laboratory coupled with a radiant ceiling that provides most of the required sensible cooling/heating energy. Flat plate collectors deliver part of the regeneration heat of the desiccant wheel during the summertime and are used for space heating during the wintertime. The system was designed for high humidity loads because of the typical climate conditions at the site and the need to support a radiant c…
Simulations of convectively-driven density currents in the Atlas region using a regional model: Impacts on dust emission and sensitivity to horizonta…
2009
[1] During the SAMUM field campaign in southern Morocco in May and June 2006 density currents generated by evaporative cooling after convective precipitation were frequently observed at the Sahara side of the Atlas Mountain chain. The associated strong surface cold-air outflow during such events has been observed to lead to dust mobilization in the foothills. Here a regional model system is used to simulate a density current case on 3 June 2006 and the subsequent dust emission. The model studies are performed with different parameterization schemes for convection, and with different horizontal model grid resolutions to examine to which extent the model system can be used for reproducing dus…
Natural Convection Cooling of a Hot Vertical Wall Wet by a Falling Liquid Film
2008
Abstract The system studied is a plane channel in which one of the two vertical walls is kept at an arbitrary temperature profile and may be partially or completely wet by a falling liquid film, while the opposite wall is adiabatic. Air from the environment flows along the channel with a mass flow rate which depends on the balance between hydraulic resistances and buoyancy forces. These latter, in their turn, depend on the distribution of temperature and humidity (hence, density) along the channel and eventually on the heat and mass transferred from wall and film to the humid air. A simplified computational model of the above system was developed and applied to the prediction of relevant qu…
Monitoring Results and Energy Performances Evaluation of Freescoo Solar DEC Systems
2016
Abstract This work addresses the energy saving performances of some solar Desiccant and Evaporative Cooling (DEC) systems working with the freescoo technology. The innovative freescoo concept is based on the use two fixed and cooled adsorption beds and advanced indirect evaporative cooling processes. The main feature of this new adsorption bed concept is to allow the simultaneous dehumidification and cooling of air. The systems analyzed have been installed in Italy last here and results based on field monitoring data are here presented. A description of the monitored systems and comparisons between the energy performances based on the main performance indicators such as EER, thermal COP, co…
Life Cycle Assessment of a compact Desiccant Evaporative Cooling system: The case study of the “Freescoo”
2016
Abstract The paper aims at exploring the performances of a compact Desiccant Evaporative Cooling system called “Freescoo” (Free Solar Cooling) in comparison to standard conventional technologies. The Freescoo – that aims at applications in the residential sector and in small office buildings and includes a photovoltaic–thermal system – is analyzed, its monitored performance discussed and reported: under cooling conditions an Energy Efficiency Ratio of 12.8 is calculated, that reaches 50.7 if also photovoltaic generation is considered. To assess the performance of the proposed system a Life Cycle Assessment study was performed to investigate the system covering all its life, from the product…
ADVANCED SOLAR ASSISTED DESICCANT AND EVAPORATIVE COOLING SYSTEM EQUIPPED WITH WET HEAT EXCHANGERS
2011
Abstract This work concerns an innovative solar assisted desiccant and evaporative cooling (DEC) system for building air conditioning. In this system, air-to-air packaged wet heat exchangers are used to maximize the exploitation of the evaporative cooling potential associated with the exhaust air stream. The thermodynamic cycle is first theoretically described, and then an example of a real application is shown. The system presented is an experimental DEC system originally installed at the beginning of 2008 at the Solar Laboratory of the University of Palermo and recently modified and updated. These modifications have been implemented with the aim to foster some problems related to the conv…
Second Generation of Freescoo Solar DEC Prototypes for Residential Applications
2015
Freescoo is an innovative all-in-one compact solar Desiccant Evaporative Cooling (DEC) air conditioner concept. Results of the first prototype developed were presented at SHC Conference last year. Now a second generation of freescoo prototypes for applications in residential and small office buildings have been installed in Italy at ENEA Casaccia and at UNIPA. The thermodynamic cycle is based on the use of fixed and cooled adsorption beds and advanced evaporative cooling concepts. The adsorption bed, which is a fin and tube heat exchanger packed with silica gel grains, allows simultaneous dehumidification and cooling of the process air. The indirect evaporative cooling process, operated dow…
Numerical evaluation on performances of AHU equipped with a cross flow heat exchanger in wet and dry operation
2012
Abstract In this paper the comparison between the performance of a cross flow heat exchanger in wet and dry operation for air handling process has been investigated. In addition, a case study of application of the component to perform indirect evaporative cooling in a AHU was studied with the software TRNSYS.Using experimental data and an appropriate analytical method, energy saving performances of the system has been evaluated through the entire cooling season for a typical Mediterranean site. Results show that high energy saving potential can be obtained if the component is operated in wet operation in term of reduction of electricity consumption.
Bose-Einstein Condensation in an electro-pneumatically transformed quadrupole-Ioffe magnetic trap
2014
We report a novel approach for preparing a Bose-Einstein condensate (BEC) of $^{87}$Rb atoms using electro-pneumatically driven transfer of atoms into a Quadrupole-Ioffe magnetic trap (QUIC Trap). More than 5$\times$$10^{8}$ atoms from a Magneto-optical trap are loaded into a spherical quadrupole trap and then these atoms are transferred into an Ioffe trap by moving the Ioffe coil towards the center of the quadrupole coil, thereby, changing the distance between quadrupole trap center and the Ioffe coil. The transfer efficiency is more than 80 \%. This approach is different from a conventional approach of loading the atoms into a QUIC trap wherein the spherical quadrupole trap is transformed…