Investigations on a Novel Internally Heated Bubble Column Liquid Desiccant Regenerator

The use of air conditioners has grown very rapidly in India and around the world in recent times due to economic growth, craving for better standard of living and rise in temperatures due to urban heat island effect as well as global warming. Electricity demand for cooling in India may increase six‐fold by 2040 due to heavy dependence of cooling technology on electrical power, most of which come from fossil fuel-based power plants having major environmental impact. Again, conventional cooling systems use refrigerants that have large global warming potential (GWP). The growth scenario of air conditioning systems seems to be unsustainable. Air conditioning systems which can use green energy or waste heat should be developed to solve this issue. Liquid desiccant (LD) based air conditioning, LDAC system, is one such promising system as the major energy input to it is in the form of heat supplied to its regenerator (desorber). LDAC systems can particularly be useful for reducing enthalpy of ambient air which is supplied into air conditioned region for maintaining good indoor air quality (IAQ). Current work investigates the performance of a novel internally heated bubble column liquid desiccant regenerator (IH_BC_LDR) of an LDAC system. The current design provides high effectiveness and addresses the troubling issue of corrosion well. The liquid desiccant is concentrated by removing water from LD by bubbling air through it and heating the LD with hot water which can come from any low temperature heat source like solar water heater. The dependence of moisture addition rate (MAR) from LD and effectiveness of the device mainly depends upon the LD concentration and the heating media temperature. This dependence is investigated in current work and efficacy of the IH_BC_LDR as a desorber capable of utilizing even low temperature heat source, around 50 °C is demonstrated.