Chapter 1 INTRODUCTION
In thermodynamics Refrigeration is the major application area, in which the heat is transferred from a lower temperature region to a higher temperature region. The devices which produce refrigeration are known as Refrigerators and the cycle on which it operates are called refrigeration cycles. Vapour compression refrigeration cycle is the most regularly used refrigeration cycle in which the refrigerant is alternately vaporized and condensed and in the vapor phase it is compressed. Gas refrigeration cycle is the well-known refrigeration cycle in which cycle refrigerant remains in the gaseous phase throughout the cycle. Cascade refrigeration are the other refrigeration cycles discussed in this chapter; absorption refrigeration is the one more refrigeration cycle which is used where the refrigerant is dissolved in liquid before it is compressed. One more refrigeration in which refrigeration is produced by passing the electric current through two dissimilar materials is called as the thermoelectric refrigeration.
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Analysis of The Cycle Fig 1.9 T-S Diagram
Fig 1.10 P-H Diagram
The various process are : Process ab: The vapour refrigerant entering the compressor is compressed to high pressure and temperature in an isentropic manner. Process bc : This high pressure and high temperature vapour then enters a condenser where the temperature of the vapour first drops to saturation temperature and subsequently the vapour refrigerant condenses to liquid state . Process cd : This liquid refrigerant is collected in the liquid storage tank and later on it is expanded to low pressure and temperature by passing it through the throttle valve. At point d we have low temperature liquid refrigerant with small amounts of vapour . Process da: This low temperature liquid then enters the evaporator where it absorbs heat from the space to be cooled namely the refrigerator and becomes vapour
1.5.4 Super Heating Fig 1.11 T-S
Ruth Schwartz Cowan wrote “How the Refrigerator Got Its Hum” in 1983. It was included in the section, “Failed Machines” of her book. I never thought about why most refrigerators are electric. We have owned gas stoves and dryers, but never a gas refrigerator. Gas appliances cost more upfront, but are inexpensive to run over time. Personally, I would rather have gas appliances than electric and believe many other people would too; however, there are major factors that caused the gas refrigerator to fail.
"Refrigerators." Canada Science and Technology Museum. Canada Science and Technology Museum, 2014. Web. 15 Feb. 2014. .
and brought to a boiling temperature then filtered out the final product is converted to
Shirley (2013) explains the steps of the theory; the first step is unfreezing. The unfreezing stage this is preparation stage. This is the stage when
In warmer climates such as Egypt they used techniques as evaporative cooling, “if water is placed in shallow trays during the cool tropical nights, its rapid evaporation can cause ice to form in the trays, even if the air does not fall below freezing temperatures”. Although refrigeration developed in the 18th century it wasn’t until the mid-19th century when the first refrigerator built using vapor technology was build by American John Gorrie in 1844. A few years later commercial refrigeration was introduced as well as vapor compression technology which was the beginning of our modern refrigeration. Later that century ammonia was popularized as the evaporation chemical in refrigeration. All the trials and tribulations of refrigeration where all stepping stones to the 20th century and the introduction of modern refrigeration as we know it
Refrigeration is the process of cooling down a space or thing below normal environmental temperature. Food preservation is vital in today’s day and age. From the meats to the dairy, everything needs to be kept at room temperature, cold, or frozen. People even like to make themselves cold and frozen by using air conditioning. But, it does make you wonder “how” and “when”. How did refrigeration become such an important invention and how did people survive without it? When did our ancestors realize it takes the cold to keep their food preserved and looking fresh? We now have fridges that have an automated ice machine and touch screens.
Norbert Rillieux invented the triple effect vacuum evaporator. The "triple effect" is for the multiple things that the system does all at the same time. The "vacuum" is for the vacuum of air that is used in the system, and the "evaporator" is for the sugarcane liquid syrup that is heated and evaporated into regular sugar. The actual system is somewhat complicated, so please see the picture that is provided.
In this paper over natural refrigerant I will be covering the pros and cons of natural refrigerant in light commercial and residential applications. There are many natural substances in this world that can be used to help or decrease the efficiency of a heating ventilation air conditioning system. Some of these substances are water, air, ammonia, and hydrocarbons. All these substances are natural that come from the earth we live on. Over the course of this paper I will be covering the pros and cons of swamp coolers, geo thermal heating and cooling units and how these natural substances can help and or decrease how your heating and cooling unit performs.
Refrigeration Refrigeration is defined as “The process of removing heat from an enclosed space, or from a substance, to lower its pressure.” (First website given in bibliography) In simpler terms, it is removing heat from states of matter in order to keep them cooler. The basic need for refrigeration is to cool food and beverages, as they often get spoilt if the temperature is high. Before actual refrigerators and other such mechanical systems were introduced, it was very common for people to cool their food with ice and snow.
Those compressors in which gas or working fluid flows parallel to the axis of rotation.
The factors for exponential growth for air-conditioning are the HVAC Market, energy, environment, communication, societal, political, preparing for the future, looking ahead, and the conclusion. Buildings of the U.S. use approximately 35% of the nation’s precise total of energy consumption. The worth of shipments by U.S. HVAC manufacturers was over $28 billion of 1996. Since there are 52,000 CHC chillers needed to be replaced among the U.S., there’s a large opportunity for new chillers, new technology for the HVAC industry. The ozone depletion is an international issue in which is currently being resolved. The 3rd world countries are still allowed to manufacture CFC’s. Illegal imports of CFC’S to the U.S. is a consistent concern. Many illegal imports are virgin CFC’s. Those whom have a political overtones are specifically the ones whom create a protectionism of local commerce, having a negative impact on those inside and out of the country.
Finally, the liquid moves to the evaporator, where heat from the inside air is absorbed and changes it from a liquid to a gas. After that, it goes again to the compressor, where the entire cycle is repeated.
... temperature of 112 0C also and a pressure 2.5 bar. Cooling water is used to condense the vapor exiting column. Remaining methane and hydrogen are separated in reflux drum where the vapor stream is combined with other gases streams. The overhead of first and second separator are combined to form fuel gas. The liquid stream exiting in the bottoms of the reflux drum is pumped at pressure of 3.3 bar for discharging pressure. The pump stream is separated in two streams. One stream is to feed to tray one of the column and the other one stream is cooled down to 38 0C in heat exchanger. Then, the cooled product stream is sent to storage.
turbine via interceptor valves and control valves and after expanding enters the L.P. turbine stage via 2 numbers of cross over pipes. In the L.P. stage the steam expands in axially opposite direction to counteract the trust and enters the condenser placed directly below the L.P. turbine. The cooling water flowing throughout the condenser tubes condenses the steam and the condensate collected in the hot well of the condenser. The condensate collected is pumped by means of 3*50% duty condensate pumps through L.P. heaters to deaerator from where the boiler feed pump delivers the water to boiler through H.P. heaters thus forming a closed
In cooler regions of the steam becomes water again and arrives in the form of rain or