12-09-2014, 02:30 PM
REFREGERATION USING WASTE HEAT IN CAR
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ABSTRACT
The project consists of an Electrolux refrigeration system using heat energy as input. This system was actually invented by two Swedish engineers, Von Platen and Carl Munters. The idea was first developed by the ‘Electrolux Company, of Luton, England, hence the name ‘Electrolux refrigeration system’. The principle behind Electrolux refrigeration is that it uses three gases to accomplish its cooling effect namely ammonia (refrigerant) water (absorbent) and hydrogen. Ammonia is used as the refrigerant as it is easily available, environmentally friendly and can produce a better cooling effect. Hydrogen is used to reduce the partial pressure of ammonia vapour in the evaporator chamber so that more ammonia evaporates yielding more cooling effect. Heat input is required at the generator where aqua ammonia is heated to get ammonia vapors. In this project, an experimental setup for Electrolux refrigeration is made using heat energy to supply input heat. A double involute cusp shaped plate is used as the solar collector. Two 1” diameter pipes welded together is placed at the focal point of the involute cusp which acts as the generator pipes. Heat energy is concentrated to these pipes by the solar collector, heating the aqua ammonia solution. The rest of the system is unaltered.
INTRODUCTION
If the heat energy possesses the advantage to be "clean", free and renewable, this last is probably, considered like an adapted potential solution, that answers in even time at a economic preoccupation and ecological problems. Among the main done currently research is the use of this free source to make operate system of refrigeration. Since among the domestic appliances used today, refrigerators consume a considerable amount of energy, using heat energy to run refrigerator is of great practical relevance nowadays.
The diffusion absorption refrigerator cycle invented in the 1920s is based on ammonia (refrigerant) and water (absorbent) as the working fluids together with hydrogen as an auxiliary inert gas. Since there are no moving parts in the unit, the diffusion absorption refrigerator system is both quiet and reliable. The system is, therefore, often used in hotel rooms and offices. The absorption diffusion refrigerating machine is designed according to the operation principle of the refrigerating machine mono pressure invented by PLATERN and MUNTER. This machine uses three operation fluids, water (absorbent), the ammonia (refrigerant) and hydrogen as an inert gas used in order to maintain the total pressure constant
PROJECT OUTLINE
When we started with our project, we were planning to utilize the nonconventional energy resources like heat energy for domestic purposes. While considering the power utilization of various domestic appliances, by knowing that a major amount of power is drawn by refrigerators, we planned to make use of heat energy to drive refrigerators which will be more economical with less wastage of electrical power. Mostly used refrigerator systems are vapour absorption and vapour compression of which vapour absorption system is more suitable when heat is used as the energy input. Our studies about the vapour absorption system led to the conclusion that Electrolux refrigeration system is best suitable for domestic purpose as it consumes less energy. Since the Electrolux system uses no pump for its working, the only energy input is in the form of heat at the generator pipe. An Electrolux system also called Platen-Munters system uses three fluids for its operation viz Ammonia, Water and Hydrogen. Hence the system is also called Three Fluid System.
We got an old Electrolux refrigeration system from the dump yard of the heat engines lab in our college. We inspected the system with the help of a professional fridge mechanic and came to a conclusion that the existing system cannot be pressurized as its piping was totally damaged. We came to know that similar system is used as mini bar in star hotels. We managed to get an obsolete Electrolux refrigerator from Leela Kempinski Hotel, Kovalam.
CONDENSATION
When the high pressure refrigerant vapour enters the condenser heat flows from condenser to cooling medium thus allowing vaporized refrigerant to return to liquid state.
COMPRESSOR
A compressor is considered to be the heart of the vapour compression refrigeration system it pumps the refrigerant through the system and circulates it again and again in cycles. It produces high pressure and hence high temperature to enable the refrigerants to reject its heat in the condenser. It also helps to produce low pressure in the evaporator to make the refrigerant to pick up maximum amount of heat from the space to be refrigerated.
The compressors used in the modern vapour compression system can be either of positive displacement or non-positive displacement type
ADVANTAGES
The coefficient of performance is quite high as the working cycle of this system is near the Carnot cycle
The among of refrigerant circulated is less per ton of refrigeration than air refrigeration system because the heat carried away by the refrigerant is the latent heat. As a result of this, the size of evaporator is smaller for the same refrigerating effect.
This system can be employed over a large range of temperatures. By adjusting the expansion valve of the same unit, the required temperature in the evaporator can be achieved.
The running cost of this system is less than air refrigerating system. The air refrigeration system requires five times more power than a vapour compression refrigeration system of the same capacity.
DISADVANTAGES
Prevention of leakage of refrigerant in this system is the major problem.
First investment cost is high than the air refrigeration system.