Heat Exchangers Technology and Applications in Heat Exchanger Engineering (original) (raw)
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Evergreen, 2018
Heat pump systems are often considered as one of the major contributors to environmental problems due to the usage of chlorofluoro, hydrochlorofluoro, and hydrofluoro carbon-based refrigerants. Earlier versions of refrigerants used to have high ODP as well as GWP. However, next generation refrigerants that are environmentally benign with excellent thermophysical properties are still under development stage. This study reviews the historical development of refrigerants, their environmental impacts and observes the viewpoint for present options in terms of Montreal Protocol, Kyoto Protocol, and EU F-gas regulation. The discussion extends to the actions of international agreements on the phase-out of hydrochlorofluorocarbons for developed and developing countries. This study also highlights the approach of large heat pump industries in Asia region regarding the use of various refrigerants. The direct CO2 emission per year from airconditioning and refrigeration sectors due to the system leakage is assessed. It also examines the major contributors of CO2 emission in every year among the various sectors for providing per kilowatt cooling effect. Finally, the ideal cycle performance is compared to various refrigerants and stated the current best option.
The impact of environmentally friendly refrigerants on heat pump efficiency
Journal of Power of Technologies, 2019
The article discusses the issue of heat pump simulation. The proper design of the equipment and its proper operation allows for lower operating costs. Exact technical and economic analysis allows for the selection of system components with the highest possible efficiency and therefore lower energy demand. The use of systems based on environmentally friendly refrigerants can ensure a long product life, which is associated with a more favorable ie. the shorter payback period of the investment made. In addition, the proper design process of equipment allows optimizing its operation. In times of rapidly increasing share of energy costs in the total cost of investment, it is worthwhile to consider the use of innovative solutions and benefit from tailor-made solutions to specific operating conditions.
Energy Procedia, 2012
Globally, the production of cold housing is seen as a major energy challenge of this new century. The economic development of developing countries, submitted their majority in hot climates, will lead to a growing demand chilling requirements. Yet currently, the production of cold solutions is mainly based on refrigeration systems major consumers of electrical energy. It is then necessary to prepare socioeconomically acceptable solutions tailored to meet those needs without compromising future international commitments on the protection of the environment, particularly for reducing greenhouse gas emissions and better protection of the ozone layer by use of refrigerants neutral. For some years now, because of their impact on the environment, the use of halogenated refrigerants has been progressively subject to quotas. In this context, the use of "natural" refrigerants becomes a possible solution. We introduce in this work the merit of redeploying these natural refrigerants as an alternative solution to replace halogenated refrigerants. The solution to the environmental impacts of refrigerant gases would therefore pass by a gas which contains no chlorine no fluorine and does not reject any CO 2 emissions in the atmosphere, in brief a green gas! The aim of our project is to contribute to the protection of our environment. Our motive being to produce cold for freezing foodstuffs and seeds, safeguarding pharmaceuticals and cooling of premises: temperature conditions, air qualities controlling and producing. This work is also concerned by a contribution to the reduction of greenhouse gases and by the replacement of the polluting cooling fluids (HCFC). It is essentially the refrigeration at low temperatures, lower than (-20°C), using the solar thermal energy, in order to improve the quality of life for many people especially in arid and semi arid regions in our country.
A Review on Refrigerants, And Effects on Global Warming For Making Green Environment
Refrigerant is the fluid used for heat transfer in a refrigerating system that absorbs heat during evaporation from the region of low temperature and pressure, and releases heat during condensation at a region of higher temperature and pressure. " This heat transfer generally takes place through a phase change of the refrigerant. This research studies various refrigerants used in the refrigeration system along with their effects on the environment, effects on global warming.
2011
The high global warming potential of most HFC fluids is forcing a change to fluids with less environmental impact. The search for the ideal refrigerant is not new, but has been ongoing for one hundred years, even though the reason for the search has changed. The paper gives a background to the present search for new refrigerants, discusses the criteria for the selection and gives some information on the status concerning introduction of new fluids. In conclusion, there is only one new refrigerant close to be put on the market, HFO1234yf. Other closely related fluids, such as HFO1234ze may be alternatives in the future. Beside these new fluids, it is believed that natural refrigerants like hydrocarbons, ammonia and carbon dioxide, as well as the low GWP, but flammable, HFC152a, will all find a place in future refrigeration and heat pump systems.
Refrigerants and their impact in the environment. Use of the solar energy as the source of energy
Energy Procedia, 2011
From household refrigerator to cooling chambers and passing by air conditioners of all types, refrigerants are widely used in both industrial and domestic equipments. These fluids, which are henceforth being banned due in particular to their environmental toxicity, are expected to be replaced. Replacing them is a difficult task considering that the only solutions currently available are the so-called "natural" refrigerants, such as ammonia, hydrocarbons and CO2. The disadvantages of these products are mainly toxicity (NH3), flammability (HC) and high pressures (CO2). However, with minimal skills and compliance with safety rules, they do not eventually prove to be more dangerous than other fluids. Our endeavour in this project is intended as a contribution to the protection of our environment. The motive being to produce cold for freezing foodstuffs, preservation of pharmaceuticals and space cooling. We aim in particular at the control of clean (white) rooms. Considering the climate situation in our country, this cold production will be supported by the use of solar energy as a power source, in order to ensure the autonomy of these areas in arid and semi arid regions. An alternative that seems promised to a bright future.
Refrigerants: There is still no vision for sustainable solutions
International Journal of Refrigeration-revue Internationale Du Froid, 2018
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights The HFCs appeared on the market because of the Montreal Protocol. We have to learn from mistakes in the past. The bodies of the Montreal Protocol ignored the climate change issue. Policies as successful examples: Denmark and EU. Visions for the future with environmental refrigerants-Ammonia systems with a small charge, preassembled in a factory.-Carbon-dioxide systems are improved and now are efficient in hot climate as well.-R290 in split air conditioners with a small charge (150 g). HFO refrigeration systems: high price and uncertainty on eco systems? A new approach: PHASE-IN OF NATURAL REFRIGERANTS which are ozone and climate friendly; it means long term and sustainable solutions.
Green Technologies Related to Refrigeration and Air Conditioning
This paper presents some such case studies for co-and tri-generating various cold and hot utilities using innovative designs of Matrix and Tube-Tube Heat Exchangers and Multi-Utility Heat Pumps developed at Heat Pump Laboratory in IIT Bombay (HPL_IITB). Techno-economic benefits of some of these installations deployed in domestic, industrial and commercial applications are discussed.
Ecological refrigerants used in refrigeration, air-conditioning and heat pump systems
The paper presents conditions in order to assure comfortable temperatures in working and living environments using cooling systems in sustaining life quality. They are treated aspects of the environmental pollution through the working fluids of the refrigeration, air-conditioning and heat pump systems and it is described the new strategy in using refrigerants in accordance with the international legislation. It is described the selection of refrigerants adapted to each utilization, based on the thermodynamic and -physical properties, the technological behaviour, costs and use constraints as principal aspects of the environmental protection. Also, it is performed a comparative analysis in function of the total equivalent warming impact (TEWI) for some possible substitutes of refrigerant R22 used in various refrigeration and heat pump systems.
Alternative Refrigerants: A Review
International Journal of Engineering Sciences & Research Technology, 2014
During the last decade, substantial research activities have been undertaken regarding refrigeration cycles and systems with particular emphasis on the replacement of refrigerants like R134a by refrigerants like hydrocarbons which have negligible GWP (Global Warming Potential).Besides using eco-friendly refrigerants, thrust has been given upon devising methods to increase the efficiency of the refrigeration cycle/system, which will also contribute to reducing emission of GHG(Green House Gases). This paper provides a review of the efforts to replace the HFCs (hydroflurocarbons) which are harmful to the environment.