This paper describes an experimental study to determine xi, a parameter defined in an earlier analytical study as the fraction of the heat of dilution in packed bed liquid desiccant dehumidifiers that goes into the air stream. Xi was determined at various operating conditions in a packed bed using calcium chloride solution as the liquid desiccant in countercurrent flow with air. Xi has been correlated in terms of L/G ratios, gas Reynolds number, the ambient number, and a new parameter, the desiccant number. An extension of the epsilon-NTU model incorporating xi is presented, and comparison with data, both present and those reported in the literature, show good agreement.