Field Study on Humidification Performance of a Desiccant Air-Conditioning System Combined with a Heat Pump

A desiccant air-conditioning system was developed as a latent-load-processing air conditioner in a dedicated outdoor air system during the summer. This study investigated the application of this air-conditioning system to humidification during the winter without using make-up water, thereby eliminating the cause of microbial contamination in air-conditioning systems. The experiments were conducted with a system used for summer applications to determine the feasibility of adsorbing vapor from outdoor air and supplying it to an indoor space. The humidification performance, energy efficiency, and operating conditions were examined. Although the conditions were subpar because the experiments were performed with an actual dedicated outdoor air system, the results showed that it is possible to supply air with a minimum humidity ratio of 5.8 g/kg dry air (DA) when the humidity ratio of outdoor air ranges from 1.8 to 2.3 g/kg DA. The minimum humidification performance required for a dedicated outdoor air system was achieved by increasing the airflow rate of the moisture-adsorption side to 2–3 times that of the humidification side. In addition, air leaking from the moisture-adsorption side to the humidification side, improving the mechanical structure, such as by the insulation of the moisture-adsorption side, and an efficient operating method were examined for humidification during the winter.

[1]  Ye Yao,et al.  Energy consumption analysis on a dedicated outdoor air system with rotary desiccant wheel , 2007, Energy.

[2]  O Seppänen,et al.  Association of ventilation system type with SBS symptoms in office workers. , 2002, Indoor air.

[3]  Xiaohua Liu,et al.  Application of Liquid Desiccant System , 2014 .

[4]  Stanley A. Mumma,et al.  Ceiling Panel Cooling Systems , 2001 .

[5]  A Hedge,et al.  Sick building syndrome: a study of 4373 office workers. , 1987, The Annals of occupational hygiene.

[6]  A. E. Kabeel.  Dehumidification and humidification process of desiccant solution by air injection , 2010 .

[7]  Seasonal variation and size distribution of bioaerosols in an air-conditioned auditorium: a case study , 2011 .

[8]  Kazuki Wada,et al.  Desiccant Humidity Control System Using Waste Heat of Water Source Heat Pump , 2009 .

[9]  B. Purushothama,et al.  Humidification and Ventilation Management in Textile Industry , 2009 .

[10]  G. Clausen,et al.  Why, when and how do HVAC - systems pollute the indoor environment and what to do about it ? The European AIRLESS project , 2003 .

[11]  José J. Costa,et al.  Effectiveness parameters for the prediction of the global performance of desiccant wheels – An assessment based on experimental data , 2012 .

[12]  Francesco Minichiello,et al.  Influence of the rotation speed on the effectiveness parameters of a desiccant wheel: An assessment using experimental data and manufacturer software , 2015 .

[13]  Edward Wolfe.  Desiccants' experimental performance characteristics and effectiveness as an air conditioning system , 1993 .

[14]  S. Jain,et al.  Experimental performance of a liquid desiccant dehumidification system under tropical climates , 2011 .

[15]  D. Vesley,et al.  Bacterial output from three respiratory therapy humidifying devices. , 1979, Respiratory care.

[16]  Chaobin Dang,et al.  Performance analysis of a no-frost hybrid air conditioning system with integrated liquid desiccant dehumidification , 2010 .

[17]  E. Dahl,et al.  Physicochemical aspects of disinfection of water by means of ultrasound and ozone , 1976 .

[18]  Yong Li,et al.  Experimental investigation and theoretical analysis of solar heating and humidification system with desiccant rotor , 2011 .

[19]  Stanley A. Mumma.  Overview of Integrating Dedicated Outdoor Air Systems with Parallel Terminal Systems , 2001 .

[20]  Ryozo Ooka,et al.  Study on Noncondensing Air-Conditioning System Performance When Combining a Desiccant Cooling System with a CO2 Heat Pump , 2006 .

[21]  Yunhan Xiao,et al.  Experimental and theoretical studies on air humidification by a water spray at elevated pressure , 2007 .

[22]  Borong Lin,et al.  Annual performance of liquid desiccant based independent humidity control HVAC system , 2006 .

[23]  José Manuel Cejudo López,et al.  Influence of the desiccant wheel effectiveness method approaches, with fix and variable effectiveness parameters, on the performance results of an airport air-conditioning system , 2015 .

[24]  Thosapon Katejanekarn,et al.  Performance of a solar-regenerated liquid desiccant ventilation pre-conditioning system , 2008 .

[25]  Clive B. Beggs,et al.  Development of a numerical model to simulate the biological inactivation of airborne microorganisms in the presence of ultraviolet light , 2004 .

[26]  Kurt Roth,et al.  Dedicated outdoor air systems , 2003 .

[27]  R. Farley,et al.  Development of a humidifier for patient ventilation using a semi-permeable tube to minimize system condensate. , 1992, Journal of biomedical engineering.

[28]  Å. Thörn.  Case study of a sick building Could an integrated biopsychosocial perspective prevent chronicity , 2000 .

[29]  Stefano De Antonellis,et al.  Desiccant wheels for air humidification: An experimental and numerical analysis , 2015 .

[30]  Peter C Raynor,et al.  Development of a method for bacteria and virus recovery from heating, ventilation, and air conditioning (HVAC) filters. , 2006, Journal of environmental monitoring : JEM.

[31]  A Thörn,et al.  The sick building syndrome: a diagnostic dilemma. , 1998, Social science & medicine.

[32]  P. V. Scarpino,et al.  The use of ultraviolet germicidal irradiation (UVGI) in disinfection of airborne bacteria , 2001 .

[33]  Gaoming Ge,et al.  Performance analysis of liquid desiccant based air-conditioning system under variable fresh air rati , 2010 .

[34]  Joon-Young Park,et al.  Application of desiccant systems for improving the performance of an evaporative cooling-assisted 100% outdoor air system in hot and humid climates , 2015 .

[35]  Yi Jiang,et al.  New type of fresh air processor with liquid desiccant total heat recovery , 2005 .

[36]  Xinhua Xu,et al.  Model-based optimal control of a dedicated outdoor air-chilled ceiling system using liquid desiccant and membrane-based total heat recovery , 2011 .