The Use of a Psychrometric Chart in the Absorption-Evaporative Cooling Refrigerator

1999 ◽  
Author(s):  
Juan R. Morales G. ◽  
Araceli Lara V. ◽  
Arturo Lizardi R. ◽  
Raymundo López C. ◽  
Alen Díaz C.
Keyword(s):  
Relative Humidity ◽  
Satisfactory Agreement ◽  
Evaporative Cooling ◽  
Gaseous Ammonia ◽  
Equilibrium Conditions ◽  
Ideal Gases ◽  
Butane Mixture ◽  
Psychrometric Chart

Abstract In the absorption-evaporative cooling refrigerator, the evaporator works with liquid butane and a gaseous ammonia-butane mixture. In order to design such a refrigerator the mixture behavior has to be known. In this paper such behavior is determined first considering an ideal gases mixture and no ammonia in the liquid butane. For this purpose a psychrometric chart for a pressure of 105 kPa is obtained. To validate these assumptions a second model is chosen that considers a certain amount of non-ideality. The selected model is represented by the equations of Peng-Robinson. The results obtained for the equilibrium conditions are compared with the 100% relative humidity of the psychrometric chart. A satisfactory agreement is found.

Test Analysis of Performance of the Direct Evaporative Cooling Air Conditioners

2013 ◽  
Vol 827 ◽  
pp. 298-301
Author(s):  
Jian Zhang
Keyword(s):  
Relative Humidity ◽  
Evaporative Cooling ◽  
Cooling Capacity ◽  
Cooling Efficiency ◽  
Air Conditioner ◽  
Test Analysis ◽  
Air Conditioners ◽  
Direct Evaporative Cooling ◽  
Cooling Air ◽  
Analysis Of Performance

The direct evaporative cooling conditioner experimental research is carried out in this paper. Analyze the influence of inlet air dry ball temperature and relative humidity to air conditioner cooling capacity and cooling efficiency, which has certain guiding significance to improve the direct evaporative cooling air conditioner performance.

Case Studies of Coupled Heat and Moisture Diffusion in Wool Beds

1969 ◽  
Vol 39 (2) ◽  
pp. 166-172 ◽  
Author(s):  
H. G. David ◽  
P. Nordon
Keyword(s):  
Mathematical Model ◽  
Relative Humidity ◽  
Heat Flow ◽  
Case Studies ◽  
Satisfactory Agreement ◽  
Moisture Diffusion ◽  
Wool Fabrics ◽  
Flow Through ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture

The predictions from a previously developed mathematical model for coupled heat and moisture diffusion in beds of hygroscopic fibers have been tested against experimental observations on wool bales and wool fabrics. The experiments on wool bales were concerned with the changes in regain and temperature consequent upon changes in the relative humidity and temperature of the surrounding air. The experiments on fabrics included measurements of temperature and regain during Hoffman pressing and measurements of heat flow through the fabric during changes in regain. Satisfactory agreement was found between the predictions from the model and the experimental observations.

Methods of cooling subjects with hyperpyrexia

1959 ◽  
Vol 14 (5) ◽  
pp. 771-776 ◽  
Author(s):  
C. H. Wyndham ◽  
N. B. Strydom ◽  
H. M. Cooke ◽  
J. S. Maritz ◽  
J. F. Morrison ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Cold Water ◽  
Evaporative Cooling ◽  
The Body ◽  
Compressed Air ◽  
Water Cooling ◽  
Reliable Index ◽  
Air Velocity ◽  
Slow Cooling ◽  
Significant Difference

Six volunteers raised their rectal temperatures to 104℉ by 40–50 minutes' work at 93℉ wet-bulb temperature. The rates of fall in rectal temperatures were studied during cooling by six different methods. The most rapid method of cooling occurred when subjects sat at rest in an air condition of 90℉ dry bulb and 87℉ wet bulb and evaporative cooling was accelerated by wetting the body surface continuously for 1 hour; no significant difference in cooling was observed between airflows of 120 ft/min. and a jet of compressed air held 1–3 ft from subjects. Merely seating individuals in air conditions of 70℉ with 20% relative humidity in still air was almost as effective. Immersion in cold water and sitting in air conditions of 90℉ (D.B.) and 87℉ (W.B.) without aiding evaporative cooling are significantly less effective than the foregoing methods. Resting subjects at 97℉ (D.B.), 93℉ (W.B.) and 120 ft/min. air velocity results in very slow cooling. ‘Afterdrop’ in rectal temperature after ice-cold water cooling may be associated with severe circulatory shock. Oral temperatures are a less reliable index of core temperature than rectal. Submitted on February 16, 1959

scholarly journals Numerical investigations of solar-assisted hybrid desiccant evaporative cooling system for hot and humid climate

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402093499
Author(s):  
Shafqat Hussain ◽  
Abdulrahim Kalendar ◽  
Muhammad Zeeshan Rafique ◽  
Patrick Oosthuizen
Keyword(s):  
Relative Humidity ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Ambient Air ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Vapor Compression ◽  
Humid Climate ◽  
Numerical Investigations ◽  
Evaporative Cooling System

This article presents numerical investigations of the solar-assisted hybrid desiccant evaporative cooling system integrated with standard air collectors for applications under the hot and humid climatic conditions of Kuwait city. The objective is to introduce the energy-efficient and carbon-free solar-assisted hybrid desiccant evaporative cooling system to alleviate the principal problems of electricity consumption and carbon emissions resulting from the use of the conventional vapor-compression cooling systems. In the normal building, during cooling load operation, the solar-assisted hybrid desiccant evaporative cooling system can cope with the cooling load particularly sensible by evaporative cooling and latent through desiccant dehumidification. The outcomes of this work indicate that solar-assisted hybrid desiccant evaporative cooling device integrated with air collectors is capable of providing average coefficient of performance of 0.85 and has the potential to provide cooling with energy saving when compared with conventional vapor-compression refrigeration systems. It was concluded that under the intense outdoor environmental conditions (ambient air at greater than 45°C and 60% relative humidity), the delivered supply air from the evaporative cooling was nearly at 27°C and 65% relative humidity. To solve this problem, the system was assisted with conventional cooling coil (evaporator of heat pump) to supply air at comfortable conditions in the conditioned space.

scholarly journals Design of a Passive Downdraught Evaporative Cooling Windcatcher (PDEC-WC) System for Greenhouses in Hot Climates

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2934 ◽  
Author(s):  
Marouen Ghoulem ◽  
Khaled El Moueddeb ◽  
Ezzedine Nehdi ◽  
Fangliang Zhong ◽  
John Calautit
Keyword(s):  
Relative Humidity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Evaporative Cooling ◽  
Cross Flow ◽  
Flow Distribution ◽  
Average Error ◽  
Ambient Conditions ◽  
Mass Flow Rates ◽  
Computational Fluid Dynamics Cfd

A windcatcher is a wind-driven natural ventilation system that catches the prevailing wind to bring fresh airflow into the building and remove existing stale air. This technology recently regained attention and is increasingly being employed in buildings for passive ventilation and cooling. The combination of windcatchers and evaporative cooling has the potential to reduce the amount of energy required to ventilate and cool a greenhouse in warm and hot climates. This study examined a greenhouse incorporated with a passive downdraught evaporative cooling windcatcher (PDEC-WC) system using Computational Fluid Dynamics (CFD), validated with experimental data. Different hot ambient conditions of temperature (30–45 °C) and relative humidity (15–45%) were considered. The study explored the influence of different spray heights, layouts, cone angles and mass flow rates on indoor temperature and humidity. The average error between measurements and simulated results was 5.4% for the greenhouse model and 4.6% for the evaporative spray model. Based on the results and set conditions, the system was able to reduce the air temperature by up to 13.3 °C and to increase relative humidity by 54%. The study also assessed the influence of neighbouring structures or other greenhouses that influence the flow distribution at the ventilation openings. The study showed that the windcatcher ventilation system provided higher airflow rates as compared to cross-flow ventilation when other structures surrounded the greenhouse.

Fluid Properties at Gas Turbine Inlet due to Fogging Considering Evaporation and Condensation Phenomena as Well as Icing Risk

2014 ◽  
Author(s):  
Christoph Günther ◽  
Franz Joos
Keyword(s):  
Relative Humidity ◽  
Gas Turbine ◽  
Ambient Air ◽  
Equilibrium Conditions ◽  
Evaporation And Condensation ◽  
The Third ◽  
Ambient Relative Humidity ◽  
Fluid Properties ◽  
Gas Turbine Compressor ◽  
Non Equilibrium

This study reports on numerically calculated thermophysical properties of air entering a gas turbine compressor after passing through an intake duct affected by different cooling techniques. Case of reference is unaffected ambient air (referenced to as unaffected) passing the intake duct. Furthermore ambient air cooled down to wet bulb temperature by (overspray) fogging (referenced to as wet) was considered. The third case shows air cooled down to the same temperature as it was reached in the wet case but by using chillers (referenced to as chilled). Equilibrium and non-equilibrium properties according to the occurring evaporation and condensation phenomena were compared. Equilibrium conditions seems to have a reduced inlet icing risk for the wet case compared to the chilled case. However comparing the wet case to the unaffected case showed a higher icing risk for the wet case at low ambient relative humidity. In contrast to equilibrium conditions a consideration of non-equilibrium conditions resulted in an increased icing risk due to almost negligible condensation rates.

scholarly journals ALTERAÇÕES MICROMETEOROLÓGICAS EM AMBIENTES PROTEGIDOS CULTIVADOS COM MINITOMATE ORGÂNICO

Irriga ◽  
2018 ◽  
Vol 21 (2) ◽  
pp. 226 ◽  
Author(s):  
Haroldo Ferreira De Araujo ◽  
Paulo Ademar Martins Leal ◽  
Thais Queiroz Zorzeto ◽  
Pâmela Santaguita Betin ◽  
Eduardo Fernandes Nunes ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Vertical Profile ◽  
Evaporative Cooling ◽  
Organic Production ◽  
Maximum Temperature ◽  
Automated Control ◽  
Amplitude Control ◽  
Shade Cloth ◽  
Production Area ◽  
E Mail

ALTERAÇÕES MICROMETEOROLÓGICAS EM AMBIENTES PROTEGIDOS CULTIVADOS COM MINITOMATE ORGÂNICO HAROLDO FERREIRA DE ARAÚJO1; PAULO ADEMAR MARTINS LEAL2; THAIS QUEIROZ ZORZETO3; EDUARDO FERNANDES NUNES4; PÂMELA SANTAGUITA BETIN5 E GUILHERME FRANCISCO PLANA SERVILHA5 1 Eng. Agrônomo, Pesquisador Doutor, Faculdade de Engenharia Agrícola, FEAGRI/UNICAMP, Av. Cândido Rondon, 501 - Cidade Universitária, Campinas - SP, 13083-875, Fone: (19) 3521-1123, [email protected] Eng. Agrícola, Prof. Doutor, Faculdade de Engenharia Agrícola, FEAGRI/UNICAMP, Campinas-SP; E-mail: [email protected] Engª. Agrícola, Doutor (a), FEAGRI/UNICAMP, Campinas-SP; E-mail: [email protected] Eng. Telecomunicações, Doutor em Eng. Agrícola, FEAGRI/UNICAMP, Campinas-SP; E-mail: [email protected] Eng. Agrícola, Graduandos, FEAGRI/UNICAMP, Campinas-SP; E-mails: [email protected] e [email protected]  1 RESUMO Várias são as tecnologias utilizadas para a modificação das variáveis meteorológicas em ambiente protegido, porém as alterações e a resposta das culturas sob essas modificações devem ser estudadas. Assim, objetivou-se avaliar as alterações das variáveis meteorológicas em horários sinóticos em diferentes alturas no perfil vertical do centro geométrico de casas de vegetação com diferentes sistemas (resfriamento evaporativo, ventilação mecânica e sombreamento), e cultivadas com minitomate orgânico. Analisaram-se dados de radiação solar, temperatura e umidade relativa do ar, sendo estas últimas nas alturas de 1, 2 e 3 m do piso, em horários sinóticos intermediários (3, 9, 15 e 21 horas) coletados nos diferentes ambientes. A partir dos resultados, notou-se que o microclima em ambientes protegidos somente com malhas termorrefletoras, pode ser caracterizado por um sensor na área de produção no perfil vertical entre 1 e 2 m e outro no bolsão térmico. A associação dos sistemas automatizados de resfriamento evaporativo, ventilação mecânica e tela termorrefletora, permitiram que a temperatura máxima e a umidade relativa do ar mínima fossem mantidas em um nível adequado. Os ambientes com tela termorrefletora móvel foram eficientes na atenuação da radiação solar global diária para a cultura. Palavras–chave: Graus tecnológicos, tela de sombreamento, controle automatizado, cultivo orgânico.  ARAÚJO, H. F.; LEAL, P. A. M.; ZORZETO, T. Q.; NUNES, E. F.; BETIN, P. S.; SERVILHA, G. F. PMETEOROLOGICAL VARIABLES IN GREENHOUSES CULTIVATED WITH ORGANIC TOMATO  2 ABSTRACT There are several technologies used for modification of the micrometeorological variables in greenhouse, but the changes and crop response to these modifications must be studied. The objective was to evaluate changes in micrometeorological air variables air in synoptic times at different heights in vertical profile at the geometric center of greenhouses with different systems (evaporative cooling, mechanical ventilation and shading) and cultured cultures grown with organic minitomate. Analyzed data of sSolar radiation, temperature and relative humidity data were assessed, the latter being thewith heights of 1, 2 and 3 m from the floor in intermediate synoptic times (3, 9, 15 and 21 hours) collected in different greenhouses. The results showed that the microclimate in greenhouses with thermal reflector screens meshes could be characterized as a sensor in the production area of the vertical profile between 1 and 2 m and other thermal pocket with readings from day to night of intermediate synoptic hours. The combination of automated evaporative cooling systems, ventilation and thermal reflector screen, allowed the maximum temperature and the relative humidity of minimum air were kept in a desired amplitude control. The mobile thermal reflector screen greenhouses were effective in the attenuation of daily solar radiation, while setting a fixed thermal reflector screen recorded values below the limit for trophic culture. Keywords: Technological Degrees, shade cloth, automated control, organic production.

scholarly journals Experimental Investigation of Thermal Performance of Aluminum Foil Coated with Polyester in a Direct Evaporative Cooling System

2021 ◽  
Vol 27 (4) ◽  
pp. 1-15
Author(s):  
Abbas Magid Taleb ◽  
Mohammed Abdulraouf Nima
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Relative Humidity ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Aluminum Foil ◽  
Adiabatic Process ◽  
Direct Evaporative Cooling ◽  
Evaporative Cooling System ◽  
Positive Impression

An experimental study was carried out for an evaporative cooling system in order to investigate the effect of using an aluminum pad coated with fabric polyester. In the present work, it was considered to use a new different type of cooling medium and test its performance during the change in the wet-bulb temperature and dry-bulb temperature of the supply air outside of the pad, the relative humidity of the supply air, the amount of air supplied (300-600) CFM and also the change of the amount of circulated water (1.75, 2.5, 4.5) liter per minute. A decrease in the WBT of the air was obtained, whereas the WBT of the air entering the pad was 26.5 . In contrast, the WBT of the outside air had reached 23  even though evaporative cooling is an adiabatic process which makes the WBT of the air that comes out of the pad is equal to the entering air WBT. The decrease in DBT is by changing the amount of air and water passing through the aluminum pad, whereas the DBT of the air entering the pad was 45 , while the DBT of the outside air had reached 29 . Also, an essential thing was obtained as this rise in the relative humidity of the air is very small 57%RH compared to the conventional pads, and this gives a positive impression as the air supplied from this pad has less moisture and its ability to carry moisture is much higher than that of air supplied from other pads. This gives a positive impression because the air supplied from this pad has lower humidity and its ability to hold moisture much higher than the air supplied from other traditional pads.

Sign in / Sign up

Export Citation Format

Share Document