Section IV: Emerging Concepts for Desiccant Systems

CHAPTER LIST

This paper presents the results of a preliminary investigation of alternative liquid desiccants for use in a hybrid desiccant air-conditioning system in which a desiccant is circulated between the evaporator and the condenser of a vapor-compression air conditioner. The liquid desiccants studied were lithium chloride, lithium bromide, calcium chloride, and triethylene glycol. Each candidate desiccant was subjected to a screening that which weighed the merits of the desiccant in terms of selected characteristics. The best liquid desiccant for the anticipated application was found to be calcium chloride.

INTRODUCTION

Desiccant dehumidification air-conditioning systems have excellent potential for cost-effective application in commercial buildings located in hot, humid climates. Hybrid liquid desiccant/vapor-compression air-conditioning systems, in particular, are promising because they take advantage of the high efficiency for heat transfer inherent in vapor-compression systems and the high mass transfer potential of the liquid desiccants. However, to be cost effective, hybrid systems must provide operational savings over competing vapor-compression air-conditioning systems and/or be less costly to manufacture. In the hybrid air-conditioning system shown in Figure 1, a desiccant is circulated between the evaporator and condenser of a vapor-compression air conditioner, providing both operational and first-coat savings.

A preliminary evaluation of...