Study on Desiccant and Evaporative Cooling Systems for Livestock Thermal Comfort: Theory and Experiments

Muhammad Kashif,Yongqiang Feng,Muhammad Sultan,Takahiko Miyazaki,Hassan Niaz,Muhammad Usman,Yasir Niaz,Muhammad M Waqas,Imran Ali,Muhammad W Shahzad

doi:10.3390/en13112675

Abstract

The present study considers evaporative cooling and desiccant unit-based air-conditioning (AC) options for livestock AC application. In this regard, proposed systems are investigated by means of experiments and thermodynamic investigations. Air-conditioning requirements for animals are theoretically investigated and temperature-humidity index (THI) is estimated. A lab-scale heat mass exchanger based on the Maisotsenko-cycle evaporative cooling conception (MEC) is set up and its performance is evaluated at different ambient air conditions. In addition, a desiccant-based air-conditioning (DAC) unit is thermodynamically evaluated using a steady-state model available in the literature. The study focuses on the ambient conditions of Multan which is the 5th largest city of Pakistan and is assumed to be a typical hot city of southern Punjab. The study proposed three kinds of AC combination i.e., (i) stand-alone MEC, (ii) stand-alone desiccant AC, and (iii) M-cycle based desiccant AC systems. Wet bulb effectiveness of the stand-alone MEC unit resulted in being from 64% to 78% whereas the coefficient of performance for stand-alone desiccant AC and M-cycle based desiccant AC system was found to be 0.51 and 0.62, respectively. Results showed that the stand-alone MEC and M-cycle based desiccant AC systems can achieve the animals’ thermal comfort for the months of March to June and March to September, respectively, whereas, stand-alone desiccant AC is not found to be feasible in any month. In addition, the ambient situations of winter months (October to February) are already within the range of animal thermal comfort.

Highlights

Air-conditioning (AC) is regulatory the conditions of subjected air in accordance with the requirements in terms of humidity and temperature
The results were collected on hourly bases (10:00 to 19:00) in July to check the dynamic performance of the proposed AC systems as shown in Figure 4; analysis of experimental Maisotsenko-cycle evaporative cooling conception (MEC) system on hourly basis for 15 July for Multan (Pakistan): (a) outlet relative humidity and temperature; and (b) effectiveness
The inlet ambient air temperature varies from 35 ◦ C and gradually increase to maximum value 38 ◦ C and declines to 36.5 ◦ C, whilst the inlet relative humidity is continuously changing from minimum value

Summary

Introduction

Air-conditioning (AC) is regulatory the conditions of subjected air in accordance with the requirements in terms of humidity and temperature. The AC is essential for humans [1] as well as for livestock [2], greenhouse AC [3], food and agricultural storage [4,5] applications In this regard, various active and passive HVAC (heating, ventilation, and air-conditioning) technologies are used around the globe e.g., vapor compression air conditioning (VCAC) [6]. Direct/indirect evaporative cooling (EC) systems and desiccant-based AC systems are gaining attention for use in ambient air for dry and humid climatic conditions, respectively [1,2]. These systems may be used for various applications like agriculture, greenhouse, livestock, marines, industries, hospitals, markets, and automobile applications [9]. These systems use much less energy as compared to compressor-based systems [10]

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