Refrigerant Purity and Container Requirements for Carbon Dioxide (CO2 R-744) Used in Mobile Air-Conditioning Systems

2016 ◽  
Author(s):  
Keyword(s):  
Carbon Dioxide ◽  
Air Conditioning ◽  
Carbon Dioxide Co2 ◽  
Air Conditioning Systems

scholarly journals Carbon dioxide as the replacement for synthetic refrigerants in mobile air conditioning

2008 ◽  
Vol 12 (3) ◽  
pp. 55-64 ◽  
Author(s):  
Dragi Antonijevic
Keyword(s):  
Carbon Dioxide ◽  
Heat Pump ◽  
Automotive Industry ◽  
System Performance ◽  
Air Conditioning ◽  
Environmental Benefits ◽  
Refrigeration Cycle ◽  
Co2 Utilization ◽  
Carbon Dioxide Co2 ◽  
Air Conditioning Systems

Based on Kyoto Protocol and the decisions of European Commission R134a refrigerant, currently dominantly used in mobile air conditioning systems, needs to be phased-out. At present automotive industry looks at carbon dioxide (CO2; R744) as the refrigerant of the future. Apart from the environmental benefits discussed are the technical characteristics of carbon dioxide refrigeration cycle and mobile air-conditioning systems in comparison to R134a refrigerant. Analyzed are challenges emerged from the use of CO2 as refrigerant and improvement opportunities in regards to increase of the system performance and efficiency. Particular attention is dedicated to the advantages of CO2 utilization in prospective automotive heat pump systems.

The Tribological Behaviors of the Surfaces Lubricated by Polyaklylene Glycol and Polyolester Oils in Carbon Dioxide Environment

2006 ◽  
Vol 321-323 ◽  
pp. 1548-1551
Author(s):  
Se Doo Oh ◽  
Tae Shik Ahn ◽  
Sung Oug Cho ◽  
Young Ze Lee
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Hard Coatings ◽  
Rotary Compressor ◽  
Wear Volume ◽  
Test Results ◽  
Sliding Surfaces ◽  
Carbon Dioxide Co2 ◽  
Air Conditioning Systems ◽  
Rotary Type

The carbon dioxide (CO2) is investigated as an alternative refrigerant to replace HFC (hydro fluorocarbon) refrigerants in refrigerators and air conditioning systems due to the environmental concerns. Because new compressors with the carbon dioxide are going to be operated under the high pressure, the tribology of sliding surfaces in the compressor becomes very important. To develop new compressors, especially rotary type, the friction and wear characteristics of sliding surfaces between a vane and a roller in the rotary compressor were evaluated in this paper. Several hard coatings, such as TiN, CrN, and WC/C, were applied on vane surfaces in order to improve the tribological characteristics, and their performances were evaluated experimentally. The vane-on-disk type sliding tests were carried out under the various sliding speeds, normal loads, and carbon dioxide pressures with an exclusive high pressure wear tester. From the tests wear volume of vane surfaces applied various coatings were compared. During the tests coefficients of friction and surface temperatures were monitored. Test results showed that WC/C coatings showed good tribological properties. TiN and CrN coated vanes showed good wear resistance properties but produced high friction.

scholarly journals Thin films for solar control applications

2009 ◽  
Vol 466 (2113) ◽  
pp. 19-44 ◽  
Author(s):  
Sapna Shrestha Kanu ◽  
Russell Binions
Keyword(s):  
Thin Films ◽  
Carbon Dioxide ◽  
Carbon Dioxide Emissions ◽  
Air Conditioning ◽  
Fossil Fuels ◽  
Visible Region ◽  
Black Body ◽  
Cold Climates ◽  
Solar Control ◽  
Air Conditioning Systems

The excessive use of heating systems in cold climates and air conditioning systems in hotter climates is resulting in the extensive use of electricity in order to maintain such systems. This in turn leads to the greater use of fossil fuels and higher emissions of carbon dioxide and other pollutant gases. The growing amount of carbon dioxide emissions is contributing to the problem of global warming, hence increasing the need for alternative technologies to heating and air conditioning systems. One such alternative is the production of thin films which can be used as window glazing coatings to construct ‘smart windows’. These windows have the greatest use within constant climates. In cold climates, windows with high solar transmittance and low thermal emittance are needed; this allows sunlight into the building to brighten the room but stops heat from escaping thus warming the room. In constantly hot climates, materials that are transparent in the visible region but reflective in the infrared, such as thin metallic coatings, can be used to ensure that the inside of the building remains cool. These solar control coatings, however, pose a problem in varying climates such as in northern and central Europe. For these cases, materials that have altering properties owing to external surroundings could be the solution. These ‘chromatic’ materials include several categories, such as photochromic glasses and polymers, thermochromic metal oxides and electrochromic materials. This review will begin with a discussion as to the chemistry behind the solar control coatings and chromic materials including ambient radiation and the ideal of a black-body object. It will then look in depth at each class of these chromic materials considering experimental results and theoretical insight as well as production techniques and applications.

scholarly journals Particle and Carbon Dioxide Concentration Levels in a Surgical Room Conditioned with a Window/Wall Air-Conditioning System

2020 ◽  
Vol 17 (4) ◽  
pp. 1180 ◽  
Author(s):  
Marcelo Pereira ◽  
Arlindo Tribess ◽  
Giorgio Buonanno ◽  
Luca Stabile ◽  
Mauro Scungio ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Air Conditioning ◽  
Particle Number ◽  
Carbon Dioxide Concentration ◽  
Operating Rooms ◽  
Number Concentration ◽  
Simultaneous Increase ◽  
Particle Number Concentration ◽  
Air Conditioning System ◽  
Air Conditioning Systems

One of the most important functions of air conditioning systems in operating rooms is to protect occupants against pathogenic agents transported by air. This protection is done by simultaneously controlling the air distribution, temperature, humidity, filtration and infiltration from other areas etc. Due to their low price, simple installation, operation and maintenance, window/wall air conditioning system have largely been used in operating rooms in Brazil, even if these types of equipment only recirculate the air inside the room without appropriate filtration and renovation with outdoor air. In this context, this work aims to analyse the performance of the window/wall air conditioning systems on indoor air ventilation in operating rooms by measuring particle number concentrations and carbon dioxide concentrations during different surgical procedures, in a single surgical room and in the nearby areas (corridor) for two cases: single surgery and two subsequent surgeries. In addition, the efficiency of the analysed air conditioning system was evaluated by comparing the ventilation level calculated in the surgical room with the ventilation required in order to maintain the carbon dioxide concentration within acceptable levels. The results showed that this type of air conditioning system is not appropriate for use in operating rooms since it cannot provide an adequate level of ventilation. The CO2 concentrations during surgeries, in fact, significantly exceeded acceptable values and a simultaneous increase in particle number concentration was observed. The results also showed that there is a high risk of contamination between subsequent surgeries in the same surgical room, due to residues of contaminants transported by the particles emitted during the surgeries that were not removed from the operating room by the air conditioning system. The particle number concentration measured in the second surgery, in fact, was approximately six times higher than in the first surgery.

Thermal Comfort Assessment in a Closed Air Conditioned ICT Laboratory at Ungku Omar Polytechnic, Malaysia

2011 ◽  
Vol 383-390 ◽  
pp. 5426-5431
Author(s):  
Salvinder S.K. Singh ◽  
Ahmad Rasdan Ismail
Keyword(s):  
Carbon Dioxide ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Indoor Environment ◽  
Negative Impact ◽  
End User ◽  
Safety And Health ◽  
Custom Made ◽  
Globe Temperature ◽  
Carbon Dioxide Co2

This paper presents an integrated experimental study of the thermal comfort in a Closed Air Conditioned ICT Laboratory at Ungku Omar Polytechnic, Malaysia. The aim of this study is to determine the level of thermal comfort in the ICT laboratory by using the Thermal Confort Measurement (TCM) equipment. The ICT laboratory is considered as an indoor environment and this study had been carried out by the use of the custom made TCM from 8.30 am till 4.30 pm. This TCM is able to investigate the level of thermal in this laboratory in aspects of the level of carbon dioxide (CO2), humidity, wind speed, ambient temperature, and globe temperature simultaneously. All the data were then compared to the standards or guidelines produced by National Institue Of Safety and Health of Malaysia (NIOSH), American Conference of Governmental Industrial Hygienists (ACGIH) and the American Standards of Heating Refrigeration and Air Conditioning Engineers (ASHRAE 55), which is currently being practiced in Malaysia. From the study that was carried out it was revealed that the level of CO2 in the ICT Laboratory exceeded the hazardous level thus can produce the negative impact to the productivity of the end user which are the student that will be using this laboratory.

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