Desiccant Air-Conditioning System for Storage of Fruits and Vegetables : Pakistan Preview

Abstract

In the present study the desiccant airconditioning system has been investigated for the on-farm storage of fruits and vegetables in Pakistan. In this regard, ideal storage zone for the studied agricultural products is established in order to ascertain the system applicability. The dehumidification performance of the silica-gel based desiccant wheel has been analysed with low regeneration temperature (50°C) by using the model of Beccali et. al. Three environmental conditions (A: highly humid, B: moderately humid & C: less humid) are considered for the analysis of desiccant airconditioning system. The latent and sensible loads of airconditioning are achieved by the silica-gel desiccant wheel dehumidification and Maisotsenko cycle evaporative cooling respectively. The results of the study envisaged that desiccant wheel performs higher dehumidification in climatic condition 'A' due to higher ambient air relative humidity as compared to the other climatic conditions. However, higher heat energy is required for its regeneration in the climatic condition 'A'. This study concluded that the desiccant airconditioning system can be efficiently used for on-farm storage of fruits and vegetables in Pakistan. Also, the renewable energy sources of the country like solar energy and bio-gas can be potentially harvested for the regeneration of desiccant wheel. The study further proposes the use of hybrid desiccant airconditioning system where standalone DAC system cannot achieve the sensible load.

Investigation of energy-efficient solid desiccant system for wheat drying

“…Therefore, it has been used for dehumidification and air-conditioning processes for various agricultural applications e.g. greenhouses [3] and agricultural product storage [4] . Certainly, desiccants possess the drying potential that can be used for various agricultural products, and consequently many studies have been reported in the literature [1,[5][6][7] .…”

“…Post-harvested agricultural products including wheat grains possess high moisture level at the time of harvest and therefore cannot be stored for a long time unless proper storage/treatment has been employed [4] . In this regard, wheat grains need to dry up to a level of 14% moisture content (dry basis) to avoid mold growth as well as the insect's attack [34,35] .…”

Energy-Efficient Air-Conditioning Systems for Nonhuman Applications

“…It is mainly due to food wasting, improper management, and high cost of food storage and transportation. Food storage is usually expensive and complicated due to the involvement of numerous physiochemical and biological processes, for example, respiration, transpiration, fermentation, and so on [7]. Moreover, storage conditions and nature of storage are completely different for different types of food, which may be categorized as follows:…”

“…For example, cooling and humidification is required in summer season of Multan (Pakistan), whereas heating and humidification is required in dry winters of Fukuoka (Japan) [3]. Certainly, there could be numerous AC applications which may require specific conditions of T a and RH, for example, animals' AC [4], greenhouse AC [2,5], agricultural products' storage and preservation [6,7], and so on. The requirements of T a and RH vary dynamically with respect to time and may even vary from species to species [4].…”

“…In the twenty-first century, lots of energy-efficient and low-cost AC systems have been studied, designed, developed and are under practice for various AC applications, for example, data center [11][12][13], museums [14][15][16], hospitals [17], automobiles [18,19], wet markets [20], marine ships [21], greenhouses [22], agricultural products storage [7], animals' thermal comfort [6], industrial processes [23], electronic cooling [24], turbine inlet air cooling [25], and so on. Most of these systems are either thermally driven or based on evaporative cooling conception.…”