Browsing by Author "Takala, Tero Tuomas"

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Applicability of absorption refrigeration in a smelter cooling system
(2013) Takala, Tero Tuomas
School of Engineering | Master's thesis
The absorption refrigeration technology was first introduced in the 1850s. However, it wasn't until a few decades ago that large-scale absorption refrigeration systems began to grow in popularity in industrial cooling. The utilization of industrial waste heat streams and the production of centralized cooling are just a few examples where the benefits of improved energy efficiency by absorption cooling can be exploited. Despite the fact that several industries already enjoy the benefits brought about by absorption cooling, the applicability of absorption refrigeration in smelter cooling is still a relatively uncharted research area. This master's thesis examines the applicability of absorption refrigeration in a smelter cooling system through a theoretical framework in a HSC-Sim flow sheet model. The simulated cooling system consists of a primary and a secondary cooling circuit as well as an integrated double-stage lithium bromide-water absorption cooling unit. The cooling water circuit of the absorption chiller unit is attached to an existing cooling tower whereas the chilled water circuit is connected to the primary cooling circuit via an additional heat exchanger. The first half of this work reviews the scientific literature on absorption cooling technology and revises the design, the theoretical performance and the limitations of absorption chillers. The review is followed by a detailed description of a five-part case study and simulation results of the HSC-Sim model. Finally, in addition to a technical feasibility analysis, a brief economic analysis based on the capital expenditure and operating expenditure of an absorption chiller is conducted. Based on the simulation results it was concluded that with the help of absorption refrigeration technology a desired smelter cooling water temperature can be maintained as long as an adequate amount of driving heat is available. Although a waste heat stream more often than not serves as a driving heat source for the chiller, providing a near zero-cost fuel, the overall operating costs of the smelter cooling system with an integrated absorption chiller generally increase due to greater evaporation losses of water in the cooling tower. Nevertheless, the suitability of absorption refrigeration in smelter cooling varies according to local climate and operating conditions. Moreover, the future potential of absorption technology for smelter cooling lies in the innovative utilization of high-temperature cooling sources combined with an absorption refrigeration system.