Investigation on Simultaneous Charging and Discharging Process of Water Thermocline Storage Tank Employed in Combined Heat and Power Units

Abstract

Thermal energy storage (TES) has become a key component in combined heat and power (CHP) generation, which enhances the load regulation capability. In line with that concept, the present work addresses a numerical study that aims at investigating and predicting the transient thermal behavior of a water thermocline storage tank that integrates into a CHP plant. Investigations are carried out on two distinct two-dimensional models. The first model studies thermocline characteristics of the heat storage system through a single charge/discharge operation. The influence of various operating parameters such as inlet flow rate and the inlet temperature of HTF are investigated. Results clarify that the thermocline thickness increases as the inlet flow rate increases and consequently, the heat storage/release period decreases. The second modified model discusses the technique of simultaneous charging and discharging operation applied in the CHP unit. Two types of operations are analyzing with (a) stable charging with continual discharging and (b) periodic charging with continuous discharging. The results ravel out that the mixing ratio of charging and discharging flow rate (Qc/Qd) has a strong influence on the operation performance. When the ratio of Qc/Qd > 1, the thermocline forms and its thickness increases with time increases. The thermocline thickness remains constant as this ratio declines to 0.625. In the case of periodic charging, both larger charging flow rate and shorter none-charging periods result in maintaining the discharge outlet temperature of HTF stable for heat supply net and discharge performance improved.

Cord medialisation in unilateral vocal fold paralysis improves forced vital capacity

“…Pre‐ and post‐medialisation mean FVC values have been reported by Cantarella et al, 13 . Asik et al 10 and ElSaeed et al, 15 and although no statistically significant differences between the pre‐ and post‐medialisation FVCs are noted, the direction of change in all reports indicates to a post‐treatment expansion of FVC with the expansion ranging from 1.5% to 19.5%.…”

“…14 Pre-and postmedialisation mean FVC values have been reported by Cantarella et al,. 13 Asik et al 10 and ElSaeed et al, 15 and although no statistically significant differences between the pre-and post-medialisation…”

Techno-economic analysis of thermal energy storage systems

“…ELSihy et al 50 investigated the stable and periodic charging with steady discharging of a water storage tank. When the charging-to-discharging ratio of flowrate exceeds unity, a thermocline appears which spreads over time.…”