(375x) An Integrated Approach to the Design and Operation of Solar-Driven Absorption Refrigeration Systems

Absorption refrigeration (AR) is gaining an increasing attention in industrial facilities to utilize process heat to partially or completely drive a cooling cycle. In this paper, we consider three sources of energy to provide the necessary heat for AR. First, excess process heat is effectively utilized instead of using coolants to remove such heat. Fossil fuels are considered as needed. Furthermore, it is desirable to consider the inclusion of solar energy as a sustainable source of heat. There are design and operational challenges in integrating these energy sources and in incorporating AR into industrial facilities. The design and efficiency of the entire system depend on numerous factors including the quantity and quality of the collected solar energy, excess process heat, and fossil fuel. Additionally, the dynamic nature of solar energy poses a complicating factor in design and operation. A systematic approach is proposed for the design of AR systems with hot water loops that are integrated with industrial facilities and employ a combination of excess process heat, fossil fuels, and solar energy. First a graphical procedure is developed to use process insights in determining key design factors. Thermal pinch analysis is performed to determine how much excess heat is available and at what temperature levels as well as the needed refrigeration and the associated temperature levels. Process integration insights are used to determine the placement of the AR system and the sources of heat. Next, a multi-period mathematical model and optimization formulation is developed for the entire system. The procedure determines the optimal mix of energy forms (solar versus fossil) to be supplied to the process, the system specifications, and the dynamic operation of the system. A case study is solved to demonstrate the effectiveness and applicability of the devised procedure.