Effects of indirect air cooling combined with direct evaporative cooling on the quality of stored tomato fruit

The use of air conditioning technology is accompanied by an increase in electricity consumption, which is linked to an intensification of fossil fuel extraction. This in turn calls for developing cooling solutions of higher energy efficiency. The aim of this study is to examine energy consumption reduction of direct evaporative cooling technology for generating cool air in hot-dry climate regions. At the initial stage, already-installed air cooling equipment with a direct evaporative cooling system was studied for the creation of two regression models of electricity consumption representing the “on” and “off” sequences. Water consumption for system operation was taken into consideration. In the following stage, inlet water temperature dependence for pre-cooling purposes for the direct evaporative cooling system was studied. A mathematical model was developed and the subsequent calculations suggested that there is no need to pre-cool water before it enters the system and therefore consume additional energy. Practical application of this study is evaluated based on the case study in Dubai. The results of this study present significant energy saving potential for system operations of the direct evaporative cooling system of approximately 122 MWh per year. The return on investment for the equipment with direct evaporative cooling in case of an office building in Dubai featuring a hot desert climate is around 4.2 years. The purpose of this study is to examine the potential advantage of air cooling equipment with direct evaporative cooling technology compared to cooling equipment without this technology. The results provide the expediency of conducting further research in this area, in particular with regards to analyzing various materials for the adiabatic precooling pads, as well as the possibility of using a newly developed metal precooling pad.

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The Influence of Indirect Air-Cooling Combined with Evaporative Cooling on Tomato Fruit Cooling Time and Temperature

Journal of Agriculture and Crops ◽

10.32861/jac.72.69.75 ◽

2021 ◽

pp. 69-75

Author(s):

Sipho Sibanda ◽

Tilahun Seyoum Workneh

Keyword(s):

Ambient Temperature ◽

Storage Temperature ◽

Tomato Fruit ◽

Evaporative Cooling ◽

Climatic Conditions ◽

Cooling Time ◽

Small Scale ◽

Air Cooling ◽

Ambient Conditions ◽

Fresh Tomato

This study developed a low cost and affordable to small-scale farmers’ indirect air-cooling combined with evaporative cooling (IAC+EC) system for storage of fruit and vegetables under both arid and hot; and humid and hot climatic conditions. Field heat from freshly harvested produce should be immediately removed through cooling to the desired storage temperature. The aim of this study was to determine the effectiveness of IAC+EC system in terms of the cooling time requirement of the fresh tomato fruit. A fresh tomato cooling experiment to remove field heat during the summer month of September in Pietermaritzburg was conducted for 36 hours where the IAC+EC system was compared to storage under ambient conditions. The results showed that 16 hours was required to reduce the flesh temperature of tomatoes to 16.5oC while the flesh temperature for tomatoes under ambient conditions followed the ambient temperature profile with time of storage. The IAC+EC system reduced and maintained the microenvironment air temperature inside the coolers to 16.50C- 19°C. The ambient temperature varied between 21 and 32°C. The results in this study are evidence that IAC+ EC system can be a choice to farmers, for cooling the fresh by reducing the field temperature after harvest.

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Designing, Modelling And Experimental Investigation Of Direct Evaporative Cooling System Coupled With Commercial Desiccant Dehumidifier

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4052378 ◽

2021 ◽

pp. 1-16

Author(s):

Abdul Basit ◽

Mariam Mahmood ◽

Adeel Waqas ◽

Majid Ali ◽

Waqas Khalid

Keyword(s):

Relative Humidity ◽

Thermal Comfort ◽

Flow Rate ◽

System Performance ◽

Evaporative Cooling ◽

Comfort Level ◽

Electric Heater ◽

Air Cooling ◽

Human Thermal Comfort ◽

Direct Evaporative Cooling

Abstract With the rising demand of clean and energy efficient air conditioning systems, evaporative air cooling technique is gaining significant attention owing to less energy consumption and environmentally safe technology in comparison with conventional refrigerants based air conditioners. In this study, commercial desiccant dehumidifier is coupled with experimentally developed Direct Evaporative Cooling (DEC) system in order to first dehumidify the air, and then pass it through DEC to achieve human thermal comfort level defined by ASHRAE standards. Under the climatic conditions of Islamabad-Pakistan, multiple experiments were carried out at different temperatures, flow rate and relative humidity of air during November, when air temperature and relative humidity was in the range of 25-30°C and 40%-60%, respectively. In order to analyze the system performance under summer ambient conditions, indoor temperature was increased by 8-10°C and relative humidity by 15%-25% in laboratory. Experimental analysis showed that the system can provide human comfort level for a range of temperature 29-39.7°C and relative humidity of 65-80% at flow rate of 180 m3/hr. In order to achieve thermal comfort at higher humidity level, DEC is coupled with commercial desiccant dehumidifier. However, due to desiccant regeneration by an electric heater in the dehumidifier, the overall power consumption of the whole system rises up to 1.95 kW. Two well-known indices Coefficient of Performance (CoP) and Energy Efficiency Ratio (EER) are used to analyze the system performance.

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Indirect Evaporative Cooling: An Efficient and Convenient Energy System

JOURNAL OF ADVANCED RESEARCH IN APPLIED MECHANICS & COMPUTATIONAL FLUID DYNAMICS ◽

10.24321/2349.7661.202006 ◽

2020 ◽

Vol 07 (3&4) ◽

pp. 26-36

Author(s):

Asiya S Pendhari ◽

Keyword(s):

Heat Exchanger ◽

Cooling System ◽

Material Selection ◽

Evaporative Cooling ◽

Energy System ◽

Air Cooling ◽

Direct Evaporative Cooling ◽

Evaporative Cooling System ◽

Flow Heat ◽

Indirect Evaporative Cooling

Evaporative cooling is now an alternative method for the conventional air cooling method. This method does not only save energy but also protect the environment from global warming and hazardous gases. Thus this system is highly efficient and eco-friendly. Evaporative cooling system is further divided into two categories that are direct evaporative cooling system and an indirect evaporative cooling system. The direct evaporative cooling system is not much efficient due to high wet bulb temperature and moisture thus rather than using the direct evaporative cooling system the indirect evaporative cooling system is preferred. This paper discusses comparative studies of performance, working principles, material selection criteria’s and various methods. It also explains the performance under different weather conditions, hybrid structure to reduce the load on the further system. It summarises various aspects like wick attained aluminium sheet is the best material for IEC or counter-flow heat exchanger is effective than parallel-flow heat exchanger. It finally results that indirect evaporative cooling system is moisture free, very effective and environment savings. That can be used in various residential and commercial sectors effectively as an alternative for conventional energy-consuming system.

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Nondestructive Quality Evaluation of Tomatoes

HortScience ◽

10.21273/hortsci.33.3.544c ◽

1998 ◽

Vol 33 (3) ◽

pp. 544c-544

Author(s):

A. Hakim ◽

A. Purvis ◽

E. Pehu ◽

I. Voipio ◽

E. Kaukovirta

Keyword(s):

Quality Evaluation ◽

Tomato Fruit ◽

Quality Attributes ◽

Internal Quality ◽

Attractive Alternative ◽

Fluorescence Techniques ◽

Nondestructive Quality ◽

Alternative Techniques ◽

Evaluation Techniques

Both external and internal quality of fruits such as tomatoes can be evaluated by different methods, but all most all of the methods are destructive. For this reason, there is a need to reassess some of the alternative techniques. Nondestructive quality evaluation is an attractive alternative. The principles of different nondestructive quality evaluation techniques such as optical, physical, and fluorescence techniques applied to tomato fruit is explained. Successful application of these techniques that could be used for evaluation of different quality attributes are illustrated. The advantages of nondestructive quality evaluation techniques are that they are very fast, easy, labor- and time-intensive, and inexpensive. These techniques could also be useful to evaluate the quality of other vegetables.

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An investigation on air cooling condenser of the close-loop self-circulation evaporative cooling large wind power generator

2011 International Conference on Electrical Machines and Systems ◽

10.1109/icems.2011.6073705 ◽

2011 ◽

Author(s):

Li Jingming ◽

Song Fuchuan ◽

Gu Guobiao

Keyword(s):

Wind Power ◽

Evaporative Cooling ◽

Air Cooling ◽

Power Generator ◽

Wind Power Generator ◽

Large Wind

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Tyrosol-Enriched Tomatoes by Diffusion across the Fruit Peel from a Chitosan Coating: A Proposal of Functional Food

Foods ◽

10.3390/foods10020335 ◽

2021 ◽

Vol 10 (2) ◽

pp. 335

Author(s):

Silvia Tampucci ◽

Antonella Castagna ◽

Daniela Monti ◽

Clementina Manera ◽

Giuseppe Saccomanni ◽

...

Keyword(s):

Tomato Fruit ◽

Storage Period ◽

Food Matrix ◽

Fruit Peel ◽

Fresh Food ◽

In Vitro Permeation ◽

Active Transfer

Chitosan is receiving increasing attention from the food industry for being a biodegradable, non-toxic, antimicrobial biopolymer able to extend the shelf life of, and preserve the quality of, fresh food. However, few studies have investigated the ability of chitosan-based coatings to allow the diffusion of bioactive compounds into the food matrix to improve its nutraceutical quality. This research is aimed at testing whether a hydrophilic molecule (tyrosol) could diffuse from the chitosan-tyrosol coating and cross the tomato peel. To this end, in vitro permeation tests using excised tomato peel and an in vivo application of chitosan-tyrosol coating on tomato fruit, followed by tyrosol quantification in intact fruit, peel and flesh during a seven-day storage at room temperature, were performed. Both approaches demonstrated the ability of tyrosol to permeate across the fruit peel. Along with a decreased tyrosol content in the peel, its concentration within the flesh was increased, indicating an active transfer of tyrosol into this tissue. This finding, together with the maintenance of constant tyrosol levels during the seven-day storage period, is very promising for the use of chitosan formulations to produce functional tomato fruit.

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Application of Taguchi and ANOVA methods in the optimisation of a direct evaporative cooling pad

International Journal of Sustainable Engineering ◽

10.1080/19397038.2020.1866707 ◽

2021 ◽

pp. 1-11

Author(s):

Azzeddine Laknizi ◽

Abdellatif Ben Abdellah ◽

Mustapha Mahdaoui ◽

Kamal Anoune

Keyword(s):

Evaporative Cooling ◽

Direct Evaporative Cooling

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Two-Stage Evaporative Inlet Air Gas Turbine Cooling

Energies ◽

10.3390/en14051382 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1382

Author(s):

Obida Zeitoun

Keyword(s):

Gas Turbine ◽

Gas Turbines ◽

Evaporative Cooling ◽

Air Cooling ◽

Vapor Compression ◽

Two Stage ◽

Turbine Cooling ◽

Riyadh City ◽

Vapor Compression Refrigeration ◽

Gas Turbine Cooling

Gas turbine inlet air-cooling (TIAC) is an established technology for augmenting gas turbine output and efficiency, especially in hot regions. TIAC using evaporative cooling is suitable for hot, dry regions; however, the cooling is limited by the ambient wet-bulb temperature. This study investigates two-stage evaporative TIAC under the harsh weather of Riyadh city. The two-stage evaporative TIAC system consists of indirect and direct evaporative stages. In the indirect stage, air is precooled using water cooled in a cooling tower. In the direct stage, adiabatic saturation cools the air. This investigation was conducted for the GE 7001EA gas turbine model. Thermoflex software was used to simulate the GE 7001EA gas turbine using different TIAC systems including evaporative, two-stage evaporative, hybrid absorption refrigeration evaporative and hybrid vapor-compression refrigeration evaporative cooling systems. Comparisons of different performance parameters of gas turbines were conducted. The added annual profit and payback period were estimated for different TIAC systems.

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Use of a membrane module for semi-direct air evaporative cooling

Indoor and Built Environment ◽

10.1177/1420326x19877510 ◽

2019 ◽

Vol 29 (10) ◽

pp. 1346-1358 ◽

Cited By ~ 1

Author(s):

Sebastian Englart

Keyword(s):

Moisture Content ◽

Relative Error ◽

Air Temperature ◽

Evaporative Cooling ◽

Cross Flow ◽

Membrane Module ◽

Transfer Model ◽

Air Cooling ◽

Heating Efficiency ◽

Circulating Water

This study discusses the use of a membrane module for semi-direct evaporative air cooling. A cross-flow membrane module was used to carry out this air treatment process. For such a flow, it was proposed to describe and solve the heat and mass transfer model as a one-dimensional problem. The mathematical model was used to determine the moisture content and air temperature at the outlet from the module and the temperature of the circulating water. Results obtained using the proposed model are in good agreement with the experimental data. The relative error for the air temperature at the module outlet did not exceed 0.5%. For the moisture content, the relative error did not exceed 4%. For the circulating water temperature, the relative error did not exceed 0.6%. This paper also discusses the heating efficiency of the evaporative cooling process. Methods for determining the unit cooling indicator and the energy efficiency ratio are also proposed.

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