# Liquid Desiccant Air Conditioning System Modelling and Analysis

## Introduction

This chapter provides a theoretical performance investigation of the liquid desiccant air conditioning technology that will be integrated alongside the SOFC in the tri-generation system. The aims of this chapter are to (1) assess a variety of liquid desiccant solutions with regard to their potential for dehumidification and suitability for integration into a liquid desiccant based tri-generation system, and (2) develop validated mathematical models to evaluate the dehumidifier and regenerator heat and mass exchangers. The evaluation of desiccant working fluids and the development of mathematical models will assist the fuel cell tri-generation system in the following respects:

- (1) Justification of the selection of an appropriate working fluid for the liquid desiccant air conditioning system.
- (2) Improved understating of the performance and operating process of liquid desiccant air conditioning systems under a variety of environmental and operating conditions. This evaluation will support the experimental work presented in Chaps. 5 and 6.
- (3) Selection of optimised conditions to operate a liquid desiccant air conditioning system in a tri-generation system set-up, with specific consideration for SOFC integration.
- (4) To confirm the feasibility of integrating liquid desiccant air conditioning and SOFC technology to form a reliable and efficient tri-generation system.
- (5) Enable the development of a SOFC tri-generation system model, presented in Chap. 4.

The modelling work presented in this chapter does not aim to progress the state of the art in the theoretical analysis of liquid desiccant air conditioning systems, but to facilitate a better understanding of the process and performance of such systems. Particularly so that conclusions may be drawn that are relevant to the integration of the liquid desiccant air conditioning system with a SOFC in a trigeneration system set-up. The work in Sect. 3.2 provides a contribution to knowledge through the assimilation of various sources of literature in order to obtain the necessary data, over the required operating range, to successfully evaluate (theoretically and experimentally) a liquid desiccant air conditioning system operating with a potassium formate solution. This data has not been previously published and available within the public domain.

This chapter is split into five sections: Sect. 3.2 evaluates three desiccant solutions with regards to their dehumidification capacity, performance and suitability for use in a tri-generation system. Section 3.3 introduces the mathematical models used to evaluate the dehumidifier and regenerator membrane heat and mass exchangers. Section 3.4 validates the developed mathematical model with published experimental data. Section 3.5 presents a dehumidifier and regenerator parametric analysis. Section 3.6 provides the chapter’s conclusions, summarising the results from the parametric analysis, and the implications these results have on the development of the fuel cell tri-generation system.