Final Report Summary - EO-D-REGENERATION (Electroosmosis for Desiccant Regeneration - Innovation Technology for air-conditioning)
As an alternative to classical air-conditioners, desiccant dehumidification systems take increasing applications because of many advantages such as energy-saving, reduction of chlorofluorocarbons application and separate control of latent load to make a more comfortable indoor air quality. In order to apply the solid desiccant repeatedly in the process, the desiccant has to be regenerated. However, the thermal regeneration used in most solid desiccant systems nowadays has high operating energy consumption and needs complicated system. Electro-osmosis is a liquid flow through the capillaries in porous media like solid desiccant driven by the electroosmotic (EO) force, which provide a possible regeneration method for solid desiccants.
This project aims to develop a novel solid desiccant dehumidification technology with EO regeneration for small air conditioning systems. The system will be suitable for powering with renewable energy sources. The objectives includes:
(1) to develop the EO regeneration method for the proposed dehumidification unit;
(2) to carry out experimental studies to investigate and optimise the characteristics and influencing factors;
(3) to develop the testing system of small dehumidification unit of solid desiccant with the EO regeneration to meet the requirement of practical application;
(4) to complete the according economic acceptance analysis.
The research task and objectives of this project had been finished according to the agreed schedule, mainly including set-up of the test bench and experiments of the EO regeneration effect, experiments of influencing factors on EO regeneration, coupling characteristic of the vapour adsorption and EO regeneration, mathematical model and performance simulation, experiments of solid desiccant system with EO regeneration, economic analysis.
The significant results had been concluded as:
(1) The experimental results showed that the electro-osmosis could remove the water from the solid desiccant with the application of the electric field and regenerate the desiccant. The EO regeneration rate was up to 2.1× 10 -6 kg s-1. The EO regeneration was proved to be a potential regeneration method for the solid desiccant system.
(2) The four improvement methods were obtained, including applying the platinum-plated titanium mesh as anode, laying a piece of filter cloth under the cathode, applying the interrupted power and optimising the electrical field strength.
(3) The EO regeneration together with the vapour adsorption had been experimentally investigated when the relative humidity of supply air is kept 70 %, and 85 % respectively. There existed the EO effect under 85 % relative humidity of supply air, but there is no EO effect when the relative humidity of supply air is equal to or lower than 70 %. And the dehumidifier prototype with EO regeneration had been fabricated and trial test showed it worked well.
(4) Economic analysis showed that the power consumption of desiccant dehumidification with EO regeneration would be 18.6 % less than that of condensation dehumidification, and would save 213 kWh power yearly if air conditioning system for one room with 20 m2 area runs 10 hours each day, and 90 days each year. The operating cost of desiccant dehumidification with EO regeneration would be 30 % less than that of thermal regeneration.
The results of this project show that the EO regeneration is one potential regeneration method for the solid desiccant system, which will provide a simple, sustainable, energy saving, healthy approach for small air conditioning systems in Europe.
There are 22 papers published, including 12 refereed journal papers and 10 conference papers. The research results had been disseminated in three international conferences: the 23rd IIR International Congress of Refrigeration, 8th International Conference on Boiling and Condensation heat transfer, and 10th IIF/IIR Gustav Lorentzen Conference on Natural Refrigerants. Presentations were given at research group / division's seminar. The fellow was integrated with the research group research students and academic staff through weekly research seminars, and also helped supervise graduate students in EO regeneration for desiccant and thermal management of low carbon vehicle.
This project aims to develop a novel solid desiccant dehumidification technology with EO regeneration for small air conditioning systems. The system will be suitable for powering with renewable energy sources. The objectives includes:
(1) to develop the EO regeneration method for the proposed dehumidification unit;
(2) to carry out experimental studies to investigate and optimise the characteristics and influencing factors;
(3) to develop the testing system of small dehumidification unit of solid desiccant with the EO regeneration to meet the requirement of practical application;
(4) to complete the according economic acceptance analysis.
The research task and objectives of this project had been finished according to the agreed schedule, mainly including set-up of the test bench and experiments of the EO regeneration effect, experiments of influencing factors on EO regeneration, coupling characteristic of the vapour adsorption and EO regeneration, mathematical model and performance simulation, experiments of solid desiccant system with EO regeneration, economic analysis.
The significant results had been concluded as:
(1) The experimental results showed that the electro-osmosis could remove the water from the solid desiccant with the application of the electric field and regenerate the desiccant. The EO regeneration rate was up to 2.1× 10 -6 kg s-1. The EO regeneration was proved to be a potential regeneration method for the solid desiccant system.
(2) The four improvement methods were obtained, including applying the platinum-plated titanium mesh as anode, laying a piece of filter cloth under the cathode, applying the interrupted power and optimising the electrical field strength.
(3) The EO regeneration together with the vapour adsorption had been experimentally investigated when the relative humidity of supply air is kept 70 %, and 85 % respectively. There existed the EO effect under 85 % relative humidity of supply air, but there is no EO effect when the relative humidity of supply air is equal to or lower than 70 %. And the dehumidifier prototype with EO regeneration had been fabricated and trial test showed it worked well.
(4) Economic analysis showed that the power consumption of desiccant dehumidification with EO regeneration would be 18.6 % less than that of condensation dehumidification, and would save 213 kWh power yearly if air conditioning system for one room with 20 m2 area runs 10 hours each day, and 90 days each year. The operating cost of desiccant dehumidification with EO regeneration would be 30 % less than that of thermal regeneration.
The results of this project show that the EO regeneration is one potential regeneration method for the solid desiccant system, which will provide a simple, sustainable, energy saving, healthy approach for small air conditioning systems in Europe.
There are 22 papers published, including 12 refereed journal papers and 10 conference papers. The research results had been disseminated in three international conferences: the 23rd IIR International Congress of Refrigeration, 8th International Conference on Boiling and Condensation heat transfer, and 10th IIF/IIR Gustav Lorentzen Conference on Natural Refrigerants. Presentations were given at research group / division's seminar. The fellow was integrated with the research group research students and academic staff through weekly research seminars, and also helped supervise graduate students in EO regeneration for desiccant and thermal management of low carbon vehicle.
