School of Energy Management at Shri Mata Vaishno Devi University, Katra is established with the objective to offer academic program and conduct research in the area of Energy, Renewable Energy and Environment related issue. Presently, the school is focussing in the research work on Solar Energy (Thermal and Photovoltaics).
To further their research in Solar Thermal, the school purchased “Thermal Energy Storage” system from Ecosense.
Why Ecosense’s Solar Thermal Lab?
Ecosense’s Solar Thermal Labs provides an end-to-end learning and training in the field of Solar Thermal. Solar Thermal Lab consists of four products which together covers the entire concepts of Solar Thermal technology, usage, and Installation.
Thermal Energy Storage System
The system has been designed to perform TES related experiment by using phase changing materials (PCM). As there are several types of PCMs, the system has been designed to perform experiment with at least two PCMs separately. Provision has also been kept to examine the combine (known as cascading) effect of two PCMs in thermal energy storage.
Stainless steel cylinders are there to contain the PCMs. To charge and discharge (store and extraction of heat) the PCMs, spiral type heat exchangers made of copper of appropriate dimensions are installed in the containers. The PCMs and heat exchangers are meticulously arranged inside the S.S cylinders. In order to block heat loss from the PCM, all the cylinders are insulated by polyurethane (PUF) foam insulation.
To visualize the phase changing process another set of arrangement is there in the system. In this set the heat exchanger-PCM duo are there inside a transparent container made of acrylic and nylon. No insulation is there in this set of arrangement.
Water is the heat transferring fluid (HTF) in the system. While hot water gives heat to the PCM during charging, the cold water absorbed heat from the same PCM during discharging. To supply water for different purposes, three tanks are there in the system. For source of energy, special arrangement has been made within the system. Besides the integrated arrangement, the system can also be connected with flat plate solar collector or parabolic trough solar collector for the source of energy.
Different parts of the systems are connected with G.I pipes of ½ inch size. To direct the heat transferring fluid as per requirement several gate valves are there in the appropriate locations. To measure different variables such as temperature, flow rate, etc., respective sensors are placed at the targeted points. There is a control unit in the system where all meters and control buttons are strategically arranged to display the reading from the respective sensors.
Ecosense installed Thermal Energy Storage System at Shri Mata Vaishno Devi University, Katra
Working of the System
The working of the system starts with filling of water in the cold HTF storage tank. Once this tank is full the water is uplifted to the HTF hot/cold source tank by switching the pump on. When water overflows the pump is switched off and heat is supplied to the water by switching on the electric heaters. Once water at required temperature is available in the HTF hot/cold source tank the appropriate vales are open and allow the hot water to flows through the heat exchanger of the targeted PCM cylinder(s). The hot water gives heat to the PCM by the process of convection and conduction on its way of flow from one end to other of the heat exchangers. This stage in which the PCMs accrued energy is known as charging stage. After giving heat to PCM the water gets accumulated into the used HTF storage tank. Hot water keeps flowing continuously through the heat exchanger till the PCM charged fully. Once the PCM stored energy up to the maximum level the hot water is stopped by closing the appropriate valve (s). With the stop of flow of hot water, the charging stage of the system gets completed. After completing the charging stage, the remaining hot water in the HTF hot/cold source tank drains out to the used HTF storage tank by unlocking the drain valve. To cool the HTF hot/cold source tank some cold water can also be pass through it from the cold HTF tank by using the pump.
The 2nd step of the experiment is extraction of heat from the PCM. This step is also known as discharging of PCM. To discharge the PCM cold water is sent through the heat exchanger of the targeted PCM cylinder from the same HTF hot/cold source tank. The cold water can also be sent from the cold HTF tank directly by using the pump. The direct option is use only when high flow rate of water is required. The cold water, while flows from one end to the other of the heat exchangers absorbed heat from the PCM. After absorbing heat the water get accumulated in the used HTF storage tank.
Ecosense installed Thermal Energy Storage System at Shri Mata Vaishno Devi University, Katra
Technical Advantages of Thermal Energy Storage System
• Artificial Source of heat
• Simple to integrate with solar thermal devices such as parabolic trough collector, Flat Plate Collector or Evacuated Tube Collector
• Inbuilt storage for two PCMs
• Easy to change the storage unit for new PCM
• Provision to perform experiment in cascading of PCMs
• Provision to perform experiment under different operating conditions (temperature, HTF, flow rate)
• Capable to give experimental knowledge of thermal resistance
• Capable to deliver in-depth knowledge about the charging, storing and discharging stages of latent heat thermal energy storage technology
• Evaluation of heat transfer during charging and discharging of PCM
• Evaluation of system thermal efficiency during charging storing and discharging the PCM
• Evaluation of overall system thermal efficiency
• Comparison of some experimentally and theoretically calculated values
Demonstration of Equipment Conducted
After Successful installation of equipments, complete demonstration of equipment conducted. The demonstration and training session was joined by faculty members and students of the department.