PRESENTATION

   The main goal of this project is to search and develop metallic hydrides integrated systems for hydrogen applications concerning energy conversion and development of a metal hydrides based heat engine powered by solar energy or residual energy. Characteristic for these hydrides systems is the wide area of possibilities to absorb hydrogen at low pressure from any source of hydrogen, to storage it and deliver this hydrogen at high pressure (compression ratio more than 30). This is used to develop a heat engine using hydrogen like a working fluid, powered by solar energy or residual heat, able to convert heat energy directly in mechanic energy in a Brayton cycle.

   The principle of operation of a water pumping system based on a metal hydride heat engine powered by solar energy is presented in figure

     Solar collector heats the water at high temperature T₂ and passes the hydrogen compressor heat exchanger, producing hydrogen desorption from metal hydride bed at high pressure P₂. The comp-ressed hydrogen feed the expansion cylinder and moves a piston attached to water pump piston. The water pump delivers a quantity of water, V_water to a pump head h_t and temperature T₁. After the desorption phase is finished, the compressor heat exchanger is passed by cool water and hydrogen from Expansion engine is absorb in the metal hydride bed, causing a backward movement of the piston and the admission of the water in the pump. Finishing the absorption phase is realized a completely cycle of the system.

     The heat engine efficiency (compression efficiency) as the rate of the isentropic work and total heat intake, has the expression:     where: P₁P₂ -  the equilibrium pressure at low temperature T₁ relative high temperature T₂; R- universal gas constant; - enthalpy of formation.

             OBJECTIVES

       The main purposes of our proposal are the following:

·   Development and characterization of hydrogen absorbent alloys with high storage capacity, and great equilibrium pressure differences at little temperature gradients (dP/dT), acquired by the modeling of their properties, based of the solid state physics and surfaces studies.

·   Elaborate new technical solutions based on advanced materials, for development of a hydrogen thermal compressing module, with fast mass and heat transfer using residual thermal energy or thermal energy from solar heat.

·   Research and development of hydrogen expansion module for water pumping actuation, able to work at high pressure and without hydrogen leakages.

·   Development of a water pumping system based on a metal hydride heat engine powered by solar energy, able to deliver water, at convenient flow and head pump, in solitude places without conventional energy access.

      The Consortium will develop hydrogen storage materials and an innovative system for water pumping based on a hydrogen heat engine powered by unconventional energies.

     THE GENERAL PROGRAM TO REALIZE THE PROJECT

STAGE I – Assessment and selection of the H₂ absorbent alloys, applicable to H₂ compression process.  

STAGE II – Analysis of conversion system: solar energy-heat energy-mechanical energy in adopted system.

STAGE III – Determination the composition of LaNi_5-xM_x, MmNi_5-xM_x and Ti_1-xZr_xCr_2-yM_y alloys for optimization of compression suitable characteristics. Modelling a rapid H₂ absorption/desorption unit.

STAGE IV - Production and structural characterization for the selected materials. Thermodynamic and kinetic characterization to H₂ absorption/desorption of the prepared alloys. 

STAGE V -  Design of the hydrogen thermal compression system and development of selected metal hydride alloys.

STAGE VI -  – Design, engineering and experiments of  the experimental model of the heat operated metal hydride based water pump.

The Romanian Consortium consists of four competent institutes ‘Hydrogen Economy” area, in order to complete the proposed objectives of the 4th Program number 2. Energy and to the specific objective of the direction of research 2.1.4 Increase ,,clean energy” technologies, actions for environment protection and “greenhouse’ effects.