Napoleon Enteria

Synergization of Clean Energy Utilization, Clean Technology Development and Controlled Clean Environment Through Thermally Activated Desiccant Cooling System

The global problems of energy supply and demand, climatic change due to artificial global warming, and providing economical and clean human comfortable condition are a complex issue. These problems have become globally political, economical and technological in the center stage of global arena. Utilization of alternative energy resources which are clean and green, hand in hand with the development of alternative clean and green technologies can indeed reduce the global and environmental problems. This paper invasions the idea of harnessing the power of clean energy resources and of developing clean technology for the production of clean environmental conditions. Synergization of clean energy resources, clean technologies and production of clean environment is implemented through the thermally activated desiccant cooling system. The experimental facility is constructed which consists of thermal energy system, desiccant cooling system and the artificially controlled environmental conditions for experimental evaluation purposes. Preliminary experimental investigation is being undertaken to evaluate the performance of the thermal energy system and of the desiccant cooling system. Based on the results, thermal energy system is functioning to its expectations. However, the desiccant cooling system still needs improvement to optimize its cooling capacity. With this study, practical combination of clean energy utilization and of clean technology development for the production of clean environment is possible through proper design and implementation.Copyright

Initial Operation and Performance Evaluation of the Developed Solar Thermal and Electric Desiccant Cooling System

The system in this article was operated for electric heating and thermal storage, thermal storage and desiccant cooling, three days of controlled system operation, and a one-day actual outdoor air conditions operation. Results show that almost 9 h of electric heating is needed to store sufficient thermal energy and that same thermal stored energy is barely enough to support the desiccant cooling operation for only 7 h. It is also shown that excess thermal energy in the tank from the previous days operation cannot support the early-hour desiccant cooling the following day.

Numerical Evaluation and Optimization of the Combined Solar Thermal and Electric Desiccant Cooling System

Novel solar thermal desiccant cooling system has been developed. Experimental operation and evaluation of the system was conducted. System optimization and parametric investigation are so important for the improvement of system performance. However, inasmuch as evaluation through experimentation is time consuming and very expensive, numerical model is made and developed for the system. The developed model is implemented in TRNSYS program. The model is validated using the experimental data of the system. Based on the result of the numerical evaluation is conducted the area of the installed solar collector area must be reduced to 8m2 . The needed electric heater heating operation is 2 hours. Reduction of the solar collector inclination angle to 30° improved the solar energy collection. Improvement of the desiccant wheel dehumidification rate increased the system total performance. Increasing the heat exchanger (HEX 2) efficiency lowered the supply air temperature with improvement of system performance. Reduction of the system electric energy consumption increased the system electric COP (ECOP). These results of the study are of great importance for the improvement of the design of the developed system, operational procedure, and performance. The relationship and effects of the variables in the study are applicable for other researches seeking the effects of the operational parameters for the solar thermal desiccant cooling system design and processes.Copyright

Performance Test of Desiccant Heating, Ventilating and Air-Conditioning System by Using Multiple Tracer Gas Dilution Method

The desiccant-based air-conditioning system consists of many heat and mass transfer components operating together with air fans. The performance test using the multiple tracer gas dilution method is important for knowing the internal and external flow rates, including the air leakages. The results of the test show the actual internal air flow rates and the sources of air leakage, and also show the interaction of air in the air-conditioned lecture room and in the mechanical room. The performance test using the multiple tracer gas dilution method in air flow and air leakages is important for a detailed evaluation of any air-conditioning system such as this desiccant-based one.

Advancement of the Desiccant Heating, Ventilating, and Air-Conditioning (DHVAC) Systems

The building sector is one of the largest end-users of primary energy sources. One of the main usages of its energy is for the maintenance of indoor environmental conditions—thermal comfort and air quality. In this regard, the selection, design and installation of the heating, ventilating and air-conditioning systems in buildings and houses are very important when considering the reduction of energy consumption and, at the same time, with the provision of the required comfortable indoor thermal environment and healthy indoor air. The desiccant heating, ventilating and air-conditioning system is one of the alternative heating, ventilating and air-conditioning (HVAC) systems for providing the required indoor thermal environment and air quality. The system can provide the required thermal comfort and air quality by means of controlling the air temperature, humidity, as well as indoor chemical and biological contents. This type of system can utilize diverse sources of energy, which is very important for the optimization of on-site and off-site available alternative energy sources. As the advancement of the desiccant heating, ventilating and air-conditioning system (DHVAC) becomes globally established by the progress in different research deliverables, designs, installations and evaluation methods, it is expected that the system will become one of the most important alternative systems for the maintenance of indoor thermal environment comfort and air quality when considering the reduced reliance on conventional energy usage.

Application of Desiccant Heating, Ventilating, and Air-Conditioning System in Different Climatic Conditions of East Asia Using Silica Gel (SiO 2 ) and Titanium Dioxide (TiO 2 ) Materials

This chapter shows the numerical investigation of the developed solar–DHVAC system applied in the East Asian climatic conditions with two different desiccant wheel coating materials—the Silica Gel (SiO2) and the Titanium Dioxide (TiO2). The system was applied in temperate climate (Beijing and Tokyo), subtropical climate (Taipei and Hong Kong) and tropical climate (Manila and Singapore). The study showed that the specification of the solar–DHVAC system varies depending on the climatic conditions. In the comparison of the two materials, it was found that the TiO2 can support lower indoor temperature and humidity ratio than the SiO2 with the same specification of the solar thermal system and DHVAC system. In general, the solar–DHVAC system can provide the required indoor temperature and humidity ratio. However, for the hot and humid climate such as in tropical, large size of the solar thermal system is needed. In addition, higher volumetric flow of air to support the high cooling load is required.

Exergetic Performance of the Desiccant Heating, Ventilating, and Air-Conditioning (DHVAC) System

The developed desiccant heating, ventilating and air-conditioning (DHVAC) system was evaluated using the exergetic method under controlled environmental conditions to determine the performances of the whole system and its components. Percentage contributions of exergy destruction of system components at different regeneration temperatures and reference temperatures were determined. Exergy destruction coefficient of different components at different regeneration and reference temperatures was presented. It was shown that exergetic performances varied with respect to the regeneration and reference temperatures. The exergetic performances based on thermal, electric, total exergy input, first definition and second definition efficiencies were shown. Based on the results, reference and regeneration temperatures affected the determination of the system performances and its components. It was shown that air heating coil (AHC), air fans and desiccant wheel (DW) contributed to large percentage of exergy destruction. Hence, the mentioned components should be given attention for further improvement in the system performances.

In-Situ Performance Evaluation of the Desiccant Heating, Ventilating, and Air-Conditioning System Using Multiple Tracer Gas Dilution Method

The desiccant heating, ventilating and air-conditioning system (DHVAC) consists of many heat and mass transfer components operating together with air fans. The performance test using the multiple tracer gas dilution method is important for knowing the internal and external flow rates, including the air leakages. The results of the test show the actual internal air flow rates and the sources of air leakage, and also show the interaction of air in the air-conditioned lecture room and in the mechanical room. The performance test using the multiple tracer gas dilution method in air flow and air leakages is important for a detailed evaluation of DHVAC.