The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. PCMs have been widely used in latent heat thermal-storage systems for heat pumps, solar engineering, and spacecraft thermal control applications. The uses of PCMs for heating and cooling applications for buildings have been investigated within the past decade. There are large numbers of PCMs that melt and solidify at a wide range of temperatures, making them attractive in a number of applications. This paper also summarizes the investigation and analysis of the available thermal energy storage systems incorporating PCMs for use in different applications.

Review on thermal energy storage with phase change materials and applications

https://cmapspublic3.ihmc.us/rid=1N3976C22-12M3P49-9V/Holladay%20et%20al.%20-%202009%20-%20An%20overview%20of%20hydrogen%20production%20technologies.pdf

An overview of hydrogen production technologies

Leu-M

Climate change and fossil fuel depletion are the main reasons leading to hydrogen technology. There are many processes for hydrogen production from both conventional and alternative energy resources such as natural gas, coal, nuclear, biomass, solar and wind. In this work, a comparative overview of the major hydrogen production methods is carried out. The process descriptions along with the technical and economic aspects of 14 different production methods are discussed. An overall comparison is carried out, and the results regarding both the conventional and renewable methods are presented. The thermochemical pyrolysis and gasification are economically viable approaches providing the highest potential to become competitive on a large scale in the near future while conventional methods retain their dominant role in H2 production with costs in the range of 1.34–2.27 $/kg. Biological methods appear to be a promising pathway but further research studies are needed to improve their production rates, while the low conversion efficiencies in combination with the high investment costs are the key restrictions for water-splitting technologies to compete with conventional methods. However, further development of these technologies along with significant innovations concerning H2 storage, transportation and utilization, implies the decrease of the national dependence on fossil fuel imports and green hydrogen will dominate over the traditional energy resources.

A comparative overview of hydrogen production processes

http://wrap.warwick.ac.uk/44841/1/WRAP_Tian_Review%20on%20thermal%20energy%20storage%20with%20phase%20change.pdf

Review on thermal energy storage with phase change materials (PCMs) in building applications

A wide variety of processes are available for hydrogen production from gaseous or liquid fuels They differ according to the nature of the primary fuel used (ammonia, methanol, ethanol, gaseous or liquid hydrocarbons, water) and to the chemical reactions involved (decomposition, steam reforming, partial oxidation, electrolysis, gasification) As recent technology progress makes hydrogen a realistic long-term energy option with little or no pollution, developments of new methods for its production and improvement of conventional technology are important This paper analyzes the recent development of hydrogen production technologies followed by an overview of conventional and renewable energy sources and a discussion about enviro-economic aspects for hydrogen production methods The results show that although renewable energy resources cannot entirely satisfy the energy demand but electrolysis associated with solar energy, wind power, hydropower and biomass are available renewable sources for significant hydrogen production

Comparison of environmental and economic aspects of various hydrogen production methods

Latent heat thermal energy storage is one of the most efficient ways to store thermal energy for heating water by energy received from sun. This paper summarizes the investigation and analysis of thermal energy storage incorporating with and without PCM for use in solar water heaters. The relative studies are classified on the basis of type of collector and the type of storage used i.e. sensible or latent. A thorough literature investigation into the use of phase change material (PCM) in solar water heating has been considered. It has been demonstrated that for a better thermal performance of solar water heater a phase change material with high latent heat and with large surface area for heat transfer is required.

R. L. Sawhney

Papers

Comparison of environmental and economic aspects of various hydrogen production methods

Solar water heaters with phase change material thermal energy storage medium: A review

Thermal cycling test of few selected inorganic and organic phase change materials

Design, development and performance evaluation of a latent heat storage unit for evening cooking in a solar cooker

An experimental study of the thermal performance of an earth-air-pipe system in single pass mode