Performance Analysis and Comparison on Energy Storage Devices for Smart Building Energy Management

TLDR

Smart building energy systems integrate multiple sources, and storage devices such as batteries, ice/heat units, and water tanks help reduce costs by maximizing renewable use and time‑of‑use pricing. The study aims to coordinate all storage devices with schedulable loads in a building using microgrid technology. A stochastic optimization problem with scenario‑tree modeling of solar radiation and demand uncertainties is solved to identify the optimal combination and capacities of storage devices. Thermal storage (ice, water tanks) effectively cuts energy costs, while batteries are often uneconomical due to high investment and short life, and uncertainty in supply and demand influences device selection.

Abstract

A smart building energy system usually contains multiple energy sources such as power grids, autonomous generators, renewable resources, storage devices, and schedulable loads. Storage devices such as batteries, ice/heat storage units, and water tanks play an important role in reducing energy cost in building energy systems since they can help sufficiently utilize renewable energy resources and time-of-use electricity prices. It is important to plan, schedule, and coordinate all the storage devices together with schedulable loads in a building facilitated by microgrid technology. To consider the above problem with uncertainties in solar radiation and demand profiles, a stochastic optimization problem is formulated and solved by the scenario tree method. The best combination and the optimal capacities of storage devices for specific building energy systems are then determined. Furthermore, the optimal operating strategy of building energy systems can be obtained. The performance analysis on the storage devices is conducted and the numerical results show that thermal storage devices (e.g., ice storage units, water tanks) are good for saving energy costs but batteries may not be economical due to their high investment cost and short lifetime. It is also observed that the aforementioned uncertainties have an impact on selecting which type and capacity of storage device should be used.