Thermal Energy Storage Techniques Research Articles

Thermodynamic evaluation of utilizing different ice thermal energy storage systems for cooling application in office buildings in Malaysia

Storage can establish balance between production and demand consumption level in almost all the energy conversion systems. The same principle is valid for cooling applications, especially when the system is supposed to operate daily during the year. This is the condition that exists in tropical climate of Malaysia. The statistical data shows that almost one-fourth of the AC energy use in the country is due to office buildings. Therefore, utilizing the cold thermal energy storage (CTES) technique can significantly reduce the energy demand. In this study, a macroscopic thermodynamic analysis of the application of five different CTES systems for an office building in Malaysia is presented. The building energy usage is recorded and the average pattern is applied for chiller selection, storage tank sizing and finally energy and exergy evaluation. The results show that all the systems are highly efficient in terms of energy with the minimum of 93% for ice harvesting and maximum of 98% for encapsulated technique. However, the exergetic evaluation implies a totally different scenario of the study. The maximum exergy efficiency is for ice on coil (internal) technique with an amount of 18%. It was also found that increasing the room set-point temperature by 5°C can reduce the exergy efficiency by 4%.

Thermal energy storage—A review of concepts and systems for heating and cooling applications in buildings: Part 1—Seasonal storage in the ground

The use of thermal energy storage (TES) in buildings in combination with space heating and/or space cooling has recently received much attention. A variety of TES techniques have developed over the past decades. TES systems can provide short-term storage for peak-load shaving as well as long-term (seasonal) storage for the introduction of natural and renewable energy sources. TES systems for heating or cooling are utilized in applications where there is a time mismatch between the demand and the most economically favorable supply of energy. The selection of a TES system mainly depends on the storage period required, economic viability, and operating conditions. One of the main issues impeding the utilization of the full potential of natural and renewable energy sources, e.g., solar and geothermal, for space heating and space cooling applications is the development of economically competitive and reliable means for seasonal storage of thermal energy. This is particularly true at locations where seasonal variations of solar radiation are significant and/or in climates where seasonally varying space heating and cooling loads dominate energy consumption. This article conducts a literature review of different seasonal thermal energy storage concepts in the ground. The aim is to provide the basis for development of new intelligent TES possibilities in buildings.

Experimental investigation of the exergetic efficiency of solar assisted and energy storage heat pump systems

In order to investigate the effects of new developments of thermal energy storage techniques on the exergetic efficiency of a solar assisted heat pump system with a thermal storage tank, an experimental set up was constructed. This experimental apparatus consists of 18 solar collectors, a latent heat thermal energy storage tank (containing phase change storage material), a heat exchanger, a heat pump with double evaporators and a circulating pump. Experimental results are obtained for typical days during each month of June, July and August for Trabzon (41°N) in this period of the research programme. The exergetic efficiencies are calculated using the experimental data and comparisons are performed among the different systems.