Experimental study of an air humidity absorption cycle based on the MHI

  • Reza Moradi
  • Mohammad Reza SaffarianEmail author
  • Morteza Behbahani-Nejad


An office drinking water cooler is converted to a humidity absorption device. The reservoir-type evaporator of the water cooler is separated, and a finned-tube evaporator is installed. A channel is installed at the inlet of the evaporator. A fan, a cool-mist humidifier, and a heater are installed inside this channel, where the amount of humidity and heat production can be adjusted. Several pressure gauges are installed at different locations of the cycle and monitor cycle performance while working. Pressure variations in different locations of the cycle are measured at various inlet air conditions. The MHI is defined as the ratio of condensation enthalpy to the total given heat. Changes of this index are evaluated by changing the input conditions. Results show that with increasing the air temperature, the condenser and evaporator pressure increases. Results of absorbed water in various MHIs show that with increasing this index, the amount of absorbed water increases. The graph of the absorbed water based on the MHI can be used to estimate the amount of water collected from this device under different climatic conditions. The amounts of collected water from this device for several different cities of Iran are presented. Results show that in high MHIs for a device with a quarter horsepower, the water production rate can reach to 250 g h−1. Also, if the device is working continuously in these conditions, it can produce about 4 kg of water per day.


Air humidity absorption Experimental analysis MHI Relative humidity Refrigeration cycle 

List of symbols


Accuracy of a sensor


Enthalpy (kJ kg−1)


Latent enthalpy (kJ kg−1)


Moisture Harvesting Index


Produced water per time (g h−1)


The heat needed to produce one kilogram of water (kJ kg−1)


Coefficient of determination


A sample relation


Temperature (°C)


Standard uncertainty

Greek letters


Relative humidity (%)


Absolute humidity (kgwater kg air −1 )







Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2019

Authors and Affiliations

  1. 1.Department of Mechanical Engineering, Faculty of EngineeringShahid Chamran University of AhvazAhvazIran

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