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Publication Date: 2012-Oct-16
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The Prior Art Database

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Air-conditioning systems are used in many parts of the world. The purpose of most systems is to provide thermal comfort and an acceptable indoor air quality for occupants. With the improvement of standard of living, occupants require more and more comfortable and healthful indoor environment. People spend 80−90% of their time indoors, and indoor environment has important effects on human health and work efficiency. The factors affecting indoor environment mainly include temperature, humidity, air exchange rate, air movement, ventilation, particle pollutants, biological pollutants, and gaseous pollutants.

From technical point of view, the most important part of the air conditioning equipment is the cooling coil. There, the air is cooled and dehumidified. The cooling coil generally can be either of direct expansion type or the chilled water type. For both types, mechanical refrigeration cycle equipment is a must to bring either the refrigerant or the water to the desired low temperature.

Almost 100% of the air-conditioning systems are based on a mechanical refrigeration system with a cycle of a cooling gas like HFC or HCFC. Mechanical refrigerating system consists mainly of the compressor, condenser, evaporator and an expansion valve. The parts that consume energy in the cycle are the compressor and the fans. The compressor, which consumes the larger portion of energy, is driven commonly by electric power.

Energy consumption dedicated to the centralised air conditioning application can be considerable especially in emerging countries (Middle East, Asia and


). For instance, the percentage of energy consumed by air conditioning systems (in buildings offices, commercial buildings, and educational institutions) in a city like



Saudi Arabia

, during the summer is over 50% of the total electric energy.

Today, no solution based on a CO2 hydrate principle is available on the market.

In the oil industry, hydrates are well known but the use we want to do with hydrates is faraway from what is known. Intense research on natural gas hydrates was conducted by the oil industry when it was pointed out that these compounds were responsible for plugging natural gas pipelines. In fact, light gases such as methane or ethane present in petroleum products are easily trapped as guest molecules in hydrate structures. The opposite is also true: other processes, such as separation technologies, employ these inclusion compounds favourably Thanks to their high gas concentration, hydrates can also be used, propitiously for either carbon dioxide sequestration or storage and transportation of natural gas.

The objective of the present work is to replace the exiting air conditioning system (HCFC/HFC refrigerants + compressor + warm heat exchanger + long pipe with refrigerant inside + cold heat exchangers) with CO2 hydrate based air conditioning system and energy consumption free (Liquid CO2 tank, water/CO2 gas/...