Study of Heat Transfer in a Brine-Based Thermal Energy Storage System

Intermittence of solar energy source is major limitation using Concentrated Solar Power (CSP). Developing Thermal Energy Storage (TES) technology is needed to use when solar radiation is not available. TES technology helps to keep a balance between demand and supply for heating. Solar thermal energy storage is used for a data center, telecommunications infrastructure and hospital which must always remain operational. Energy Storage System (ESS) was used for special industry field in the past. However, as new technologies are developed, the market has become bigger significantly with the rising number of major industrial machinery. The main challenges of developing TES technologies are low cost. Reducing the cost of TES has been targeted by U.S. Department of Energy (DoE) for many decades. The Solar Energy Technologies Office set goals for 2030 which cut the levelized cost of energy of photovoltaic to $0.03 per kWh for utility scale. To reach this goal sooner, there is need to develop new technology for TES. Reverse Osmosis (RO) method is used to purify water in many industries. This process produces undesired product which is RO concentrate. The RO concentrate is mixture of salts (brine) which are dissolved in water. Companies need to pay environmental fees to dispose this discharge. By being paid brine from companies, the cost will be negative and it can be used as medium for TES. Brine can be evaporated, processed and packed in sealed containers for storing thermal energy. On this system, brine does not expose to environment, so it does not have bad effects on environment. The properties of brine help to cut down the cost of container for medium. When it contains brine in the thermal energy storage elements, the inside of tube design must be considered with extending surface for heat transfer enhancement. Identifying proper model will give more high efficiency for TES.