Air dryer using waste heat of HVAC systems – Code development and experimental validation

Mohamad Ramadan*, Rabih Murr, Mahmoud Khaled, Abdul Ghani Olabi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Heating, ventilating and air conditioning systems operate on the principle of refrigeration cycle. At the condenser, heat is dissipated in form of hot air which represents a rich source of heat that could be utilized to supply other systems. In the frame of this paper a novel design allowing to recover the waste heat of condenser is proposed. The recovered heat is utilized to supply a dryer. In addition, an in-house code is developed allowing to simulate different scenarios. Moreover, the code is validated experimentally through a set up. Results show the accuracy of the code where the values, obtained experimentally and numerically, are almost the same. Furthermore, several key parameters are analyzed. It has been shown that an HVAC system of 12,000 Btu/h can cover the drying needs of 4 people if it operates for 6 h. To broaden the analysis, the system is assessed by performing economic and environmental studies, in order to examine the saving that could be provided by such system as well as the reduction in CO2 emissions for the case of Lebanon. It was interestingly found that utilizing the suggested system allows to yearly save up to 228.8$ and reduce CO2 emissions by 1249.6 kg. That said, a commercial version of the system is suggested and discussed as a first baseline toward the industrialization of the concept.

Original languageEnglish
Pages (from-to)302-311
Number of pages10
JournalApplied Thermal Engineering
Early online date20 Oct 2018
Publication statusPublished - 25 Jan 2019


  • Drying
  • Energy
  • Experimental measurements
  • Heat recovery
  • HVAC
  • Lebanon
  • Renewable energy


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