Experimental investigation on mass transfer for regeneration of liquid desiccant

Abstract

Desiccants can be used in conjunction with solar energy to provide a viable alternative to traditional air conditioning techniques. Liquid desiccant regeneration was proved to be an effective method to extract the moisture from solution with a relatively less energy in order to regenerate the desiccant. An experimental study was carried out to analyze the effect of temperature for regeneration process using an injected air through the liquid desiccant solution (calcium chloride dihydrate) by a dryer. Many tests with different operating conditions such as air temperature, humidity ratio, air velocity and solution level are investigated in order to demonstrate that this salt is capable to absorb moisture and can be regenerated at a low temperature. Experimental results showed that the mass transfer is affected by the air conditions. Also, the vapour pressure difference between the air and liquid desiccant surface is the driving force of the mass transfer process. In this analysis it was also determined that the CaCl2.2H2O could be regenerated at low temperature around 48 to 60°C hence the possibility of using the flat plate solar collectors for its regeneration and this salt can be used in a system (LDCS).