Deterministic model for an indirect ice-storage tank.

摘要

A deterministic numerical model, based on a quasi-steady state and a resistance network technique is developed for an indirect ice storage-tank, type internal-melt, with built-in spiral coil-tubing heat exchanger. This model is able to simulate both charging and discharging modes, taking into account the overlapping phenomenon which occurs due to the ice or water layers' superposition, the cool down of the water at the start of the charging period, and the warm up of the water at the end of the discharging period.; The input variables required for this model are the geometric parameters of the tank, the brine temperature and flowrate entering the tank, and the user-defined number of segments along the coil and time-step. The model determines the time variation of the heat transfer rates, of the inventory of the ice, and of the secondary variables such as the brine, tubing wall, water and ice temperatures along the coil. In addition, the growth of the ice/water radius at each segment and the pressure loss of the brine along the coils at each time-step are evaluated.; To validate the numerical model, an experimental work is performed in the Larson Laboratory at the Joint Center for Energy Management. An indirect ice-storage tank is integrated in the HVAC plant of the laboratory, and outfitted with the appropriate instruments. Different loads are imposed on the HVAC system to simulate the desired brine temperatures and flowrates entering the tank. A total of five charging/discharging cycle tests are performed. The measured data arising from the experimental work is used to validate thoroughly the numerical model. In addition, an analytical model is developed to validate the limiting case of the numerical model.; A parametric and an economic analysis are performed to evaluate the ice-tank performance for different designs, as well as for different tank-capacity arrangements to meet the same load. This numerical model can be used by engineers and designers to improve their designs as well as to better analyze the energy performance of these indirect systems.