Page 1 International Sorption Heat Pump Conference, March 31-April 3, 2014 International Sorption Heat Pump Conference, Center for Environmental Energy, Engineering, University of Maryland ISHPC 2014 Hybrid Air Conditioning System M V Rane 1 * and A S Hundiwale 2 1 IIT Bombay, Heat Pump Laboratory, Mechanical Engineering Department Powai, Mumbai 400076, Maharashtra, INDIA Phone - (91 22) 2576 7514, Fax - (91 22) 2572 4544, Email - ranemv@iitb.ac.in 2 IIT Bombay, Heat Pump Laboratory, Mechanical Engineering Department Powai, Mumbai 400076, Maharashtra, INDIA ABSTRACT A 1.5 TR nominal capacity compressor is used to integrate a Hybrid Air Conditioning System, HACS in the Heat Pump Laboratory IIT Bombay, HPL_IITB. This system uses patented diabatic contacting devices with rotating disk assemblies to enable effective heat and mass transfer between Liquid Desiccant, LD, and air. Indoor air is cooled and dehumidified in single step to the required dry bulb temperature and relative humidity. Evaporator of vapour compression system integrated within the indoor diabatic contacting device helps remove the heat of absorption of moisture along with sensible cooling of indoor air. Dilute LD exiting the indoor diabatic contacting device is preheated in a solution heat exchanger before it is introduced into the outdoor diabatic contacting device, where it is regenerated using the condenser heat. Moisture from the LD is rejected into the outdoor air in the outdoor contacting device. As the LD is capable of dehumidifying the indoor air at the temperature significantly higher than the dew point temperature of the indoor air, the refrigerant evaporation temperature can be significantly higher than that in the conventional vapour compression based air conditioners. Also as the condenser heat is rejected in the outdoor diabatic contacting device while regenerating the LD, the refrigerant condensing temperatures are lower than those typical in air-cooled air conditioners. Combined effect of higher evaporating temperature and lower condensing temperature can result in substantial increase in cooling capacity and COP for a given compressor. This paper presents the details of three stage diabatic contacting devices, with advantages like no LD carryover in the air streams, very low pressure drop across the diabatic contacting devices, compact system based on high surface density rotating contacting media, low parasitic power for the rotor and the blowers. Experimental results of a 1.5 TR HACS will be presented to prove the techno economic benefits of such a system to meet the requirement of comfort air conditioning. Keywords: Hybrid Air Conditioner, Dehumidification, Desiccant, Diabatic Contacting Device, Energy Efficient. 1. INTRODUCTION Developing improved energy efficient as well as environmental friendly air conditioning system has been the primary focus in recent times. Liquid desiccant dehumidification system driven by low-grade heat sources can satisfactorily meet those needs. Effective humidity control using low temperature heat source can be a better option compared to the conventional method of humidity control which cools the air below its dew point temperature. Desiccant materials are mainly classified as solid (adsorbent) and liquid (absorbent), which correspond to adsorption and absorption processes in an air dehumidification processes respectively. Liquid desiccant have recently been applied in air dehumidification (Mehta, 2013; Jindal, 2012; Bergero and Chiari, 2011; Qiu and Riffat, 2010; Mei and Dai, 2006; Daou et al., 2004; Kessling et al., 1999; Riffat et al., 1999; Pesaran et al., 1992) and has shown some advantages over a solid adsorbent, including lower pressure drop of air across desiccant material, their ability to remove dust and removal by filtration, ease of manipulation and greater mobility. Liquid desiccants which are in use are H2O/LiBr, H2O/LiCl, and H2O/CaCl2 (Hassan and Hassan, 2009), H2O/KCOOH (Qiu and Riffat, 2010) etc.