Tag: cryogenic

Using Air to Store Energy

Authored by Dr. Rohan Dutta (Former Postdoctoral Fellow at the Cryogenic Engineering Centre) and Dr. Pavitra Sandilya, Assistant Professor, Cryogenic Engineering Centre

Highlights of the Research

  • Potential application: Large-scale energy storage system throughout the world. With its demonstrated efficiency as high as 55% to 90%, this invention is a potential alternative to existing systems including compressed air energy storage and similar technologies.

  • Possible end users: Various power generation and distribution agencies, large energy-intensive industries (iron and steel, cement, chemical, petrochemical, LNG handling, glass etc.) with the potential of low and medium grade waste heat.

  • Potential of marketability: Large; considering the growth of demand for large, grid-scale energy storage systems due to penetration of renewable energy sources in the power market.

With an ever-increasing population and the economy, the gap between power demand and generation is also increasing worldwide. The power sector has to bridge this gap. One way of tackling such a situation is by developing large-scale energy storage systems. These systems store the excess energy when the power supply is in excess of demand. The stored energy is then released when the demand for power increases.

Cryogenic Energy Storage (CES) system is one of the alternatives for energy storage.

Compared to the more common energy storage technologies like pumped-hydro, compressed air energy storage systems, the CSE system offers advantages because it is scalable, not location-specific, clean, and sustainable with virtually no cost for working fluid (air) and no greenhouse gas emission.

A typical CES process involves two alternately operated charging and discharging processes. In the charging process or a liquefaction process, the air is liquefied by using the excess power to compress the ambient air to high pressure of about 120-150 bar and stored. During the discharging process or a power cycle, the stored energy is released during the deficit period of power by first regasifying the liquefied air to high pressure (about 150 bar), and then expanding this compressed air to run a turbine for power generation.

Hitachi, a Japanese multinational conglomerate, developed and demonstrated similar versions of the CES system using air. However, the energy storage efficiencies of these systems were not comparable with those of the prevalent energy storage technologies. In 2006, UK-based company HighView Power® started developing a modular liquid air energy storage system that was scalable to gigawatts-hr of energy storage and could be taken to the customer site. Using the equipment available in the conventional power, and oil and gas industries, they obtained a significant increase in the turnaround efficiency (ratio of energy output to energy input).

Through our work, we demonstrated that the turnaround efficiency of the CES system would get enhanced by:

  1. Using the heat of compression during the liquefaction process in an Organic Rankine Cycle to produce power during the discharging process
  2. Pre-cooling the working fluid using traditional room temperature closed-cycle refrigerator during liquefaction
  3. Introducing multistage turbines with intermediate heating and an appropriate combination of turbine and valve at the last stage of liquefaction
  4. Heat integration between liquefaction and power cycles by using waste heat from the liquefaction stage as well from industries, and cooling using the waste-cold from the power cycle as well as external sources such as LNG regasification plants, etc.

A prototype of a packed-bed-based waste-cold storage method using commonly found and cheaply available pebbles has been developed at a laboratory scale. This was found to be the most critical to the successful implementation of the process modifications as observed in the study of operability of the modified process by process simulation.

A plant with the afore-mentioned modifications was shown to have not only higher overall turnaround efficiency, but also a lower payback period than a plant not using waste heat and refrigeration.

A patent has been filed already.

Cite Paper: 

1. Dutta, Rohan and Sandilya, Pavitra, Experimental Investigations on the Cold Recovery-Efficiency of a Packed-bed in a Cryogenic Energy Storage System, CEC-ICMC 2019, Connecticut Convention Centre, Hartford, USA, 21-25 July 2019. https://www.academia.edu/43848430/Experimental_Investigations_on_the_Cold_Recovery_Efficiency_of_a_Packed_bed_in_a_Cryogenic_Energy_Storage_System

2. Dutta, Rohan and Sandilya, Pavitra, Improvement Potential of Cryogenic Energy Storage Systems by Process Modifications and Heat Integration, Energy, 221, April 2021, 119841 DOI:10.1016/j.energy.2021.119841

IIT KGP Researchers Design Award-winning for Cardiovascular Device Testing Technology

Researchers from IIT Kharagpur have designed an automated smart device for online testing of cardiac medical devices and prosthetics. The device is capable of creating life-like simulations in cardiac failure cases due to various diseases and tests the performance of implantable devices and prosthetics such as Ventricular assist devices.

The World Health Organization reported 17.9 million deaths in 2016 from cardiovascular diseases (CVD) accounting for about 31% of global deaths. In India, over 28% of the deaths are due to CVD in 2016 according to a study published in 2018. According to the business intelligence company Fior Markets, the global cardiovascular devices market is expected to grow from USD 42.61 billion in 2019 to USD 71.05 billion by 2027, at a CAGR of 6.6% during the forecast period 2020-2027. These devices would include surgical devices as well as diagnostic and monitoring devices covering a large range of CVDs – Cerebrovascular Heart Disease, Stroke, Sudden Cardiac Arrest and Coronary Heart Disease. With rapid development in medical devices, especially for the implants, rigorous testing and assessment are essential during the developmental stage. 

“The intriguing complexity of physiology and function of the heart makes it difficult to carry out an in-depth study of the live organ. For researchers, the study of a cadaver heart does not provide many clues regarding its functioning in live conditions. This limitation led us to design a novel heart analogue model, Cardiovascular Replicator (CVR), which can serve as a platform for studying the cardiovascular system,” said lead researcher Prof. Prasanta Kumar Das from the Dept. of Mechanical Engineering. 

The Cardiovascular Replicator (CVR) developed by the team is an electromechanical system that can mimic the entire hemodynamics of the human heart along with its pulmonic and systemic circulations.

“The device enables us to simulate a long-range of heart diseases and conditions like aortic valve stenosis, ventricular septal defects, fetal circulation, cross circulation, single ventricle conditions and Fontan correction etc. along with hardware in the loop simulation. We can also run tests prior to animal trials,” said researcher Sumanta Laha.

The design is equipped with sensors and a widescreen display which facilitates online real-time data monitoring and logging. This system is made in a modular way to ease transportation and enable improvisation.  

Prof. Indranil Ghosh from the Cryogenic Engineering Centre pointed out the pedagogical advantage of the device for the medical community.

“Cardiovascular Replicator will not only be of great value for researchers working in medical technology innovation but also for medical students during their practical training due to the experiential learning from real-life simulations of the diseases,” he said.

The research has been awarded the prestigious SITARE – Gandhian Young Technological Innovation Award 2020 for this work titled ‘Automated Cardiovascular Replicator for Online Assessment of Cardiac Assist Devices, Prosthetics and Beyond’.