Design and Fabrication Of LPG Refrigeration System Report Download

ABSTRACT

This work investigates the result of an experimental study carried out to determine the performance of domestic refrigerator when a propane-butane mixture is liquefied petroleum gas (LPG) which is locally available and comprises 24.4% propane, 56.4% butane and 17.2% isobutene which is very from company to company. The LPG is cheaper and possesses an environmental friendly nature with no ozone depletion potential (ODP). It is used in world for cooking purposes. The various methods of refrigeration on the basis of standard refrigerant discussed. He refrigerator used in the present study is of medium size with a gross capacity of 125 litre and is designed to work on LPG. The performance parameters investigated is the refrigeration effect in certain time. The refrigerator worked efficiently when LPG was used as refrigerant instead of CFC 12. The evaporator temperature reached -5 ºC with and an ambient temperature of 12 ºC. Also from the experiment which done in atmospheric condition, we can predict the optimum value of cooling effect with the suitable operating condition of regulating valve and capillary tube of the system. The results of the present work indicate the successful use of this propane-butane mixture
as an alternative refrigerant to CFC 12 in domestic refrigerant.

INTRODUCTION

从广义上讲，“制冷”一词用于从物质中去除热量（即冷却）的过程。它还包括降低和维持周围环境一般温度以下身体温度的过程。换句话说，制冷意味着从人体中持续提取热量，其温度已经低于周围环境的温度。

For example, if some space (say in cold storage) is to be kept at -2 ºC, we must continuously extract heat which flows into it due to leakage through the walls and also the heat, which is brought into it with the articles stored after the temperature is one reduced to -2 ºC. Thus in a refrigerator, heat is virtually being pumped from a lower temperature to a higher temperature. According to second law of thermodynamics, this process can only be performed with the aid of some external work. It is thus obvious, that supply of power (say electrical motor) is regularly required to drive a refrigerator. Theoretically, the refrigerator is a reversed heat engine, or a heat pump which pumps heat from cold body and delivers to a hot body.
The substance which works in a heat pump to extract heat from a cold body and to deliver it to a hot body is called refrigerant.

家用冰箱类型

There are two types of domestic refrigerator.
1.单门新鲜食品冰箱
2.双门冰箱冰箱

Most domestic refrigerator are of two types – either a single door fresh food refrigerator or a two-door refrigerator-freezer combination, with the freezer compartment on the top portion of the cabinet, or a vertically split cabinet (side-byside), with the freezer compartment on the left side of the cabinet. They are completely self-contained units and are easy to install. Most refrigerators use R-22 refrigerant, normally maintaining temperatures of 0 ºF in the freezer compartment and about 35 ºF to 45 ºF in the refrigerator compartment.

LPG REFRIGERATION

在印度，由于其出色的热力学和热力学特性，超过80％的家用冰箱使用HFC 134A作为制冷剂。但是，HFC 134A具有1300的全球变暖潜力（GWP）。考虑到该领域和未来市场的现有冰箱，需要评估各种制冷剂选择。

CFC主要被平流层中的紫外线辐射破坏。在高平流层中释放的氯将臭氧的分解催化为氧。紫外线辐射渗透到较低的高度。对效果的幅度的可靠计算（Hoffman 1987）和他的团队预测，一百年后，全球臭氧排放量为70万吨。汽车空调的臭氧影响也不能忽略。可以将氢氟化合物（HFC）视为替代品，但不幸的是，HFC像R-134A的辐射特性使它们成为强大的全球变暖剂。据报道，HFC 134A和HC混合物是CFC 12的替代品，但它们在系统的能源效率，易燃性和可使用性方面具有自己的缺点。HFC 134A与矿物油不可混淆，因此建议使用多醇酯油，这本质上是高度吸湿性的。这种吸湿性需要严格的服务实践，否则会导致进入系统的水分进入。

PROPERTIES

» Colourless.
» Odourless. (It’s normal to odorise LPG by adding an odorant prior to supply to the user, to aid the detection of any leaks).
» Flammable.
» Heavier than air.
» Approximately half the weight of water.
»无毒，但会引起窒息。
» LPG expands upon release and 1 litre of liquid will form approximately 250 litres of vapour.

好的混合物：

LPG is mainly Propane (C3H8), Butane (C4H10) or a mix of Propane/Butane. Since LPG has such a simple chemical structure, it is among the cleanest of any alternative fuel.

Boiling point :

LPG’s boiling point ranges from -42 ºC to 0 ºC depending on its mixture percentage of Butane and Propane.

燃烧：

液化石油气的燃烧产生二氧化碳（CO2）和水蒸气，但必须有足够的空气。电器不足或通风可能导致一氧化碳产生，这可能是有毒的。

Vapour pressure :

LPG is a stored as a liquid under pressure. It is almost colourless and its weight is approximately half that of an equivalent volume of water. The pressure inside a closed container in which LPG is stored is equal to the vapour pressure of the liquid and corresponds to its temperature.

Ignition temperature :

The temperature required to ignite LPG in air is around 500 ºC.

Calorific value :

The calorific value of LPG is about 2.5 times higher than that of main gas so more heat is produced from the same volume of gas.

Toxicity :

LPG是一种无色，无味和无毒气体。它在商业上提供了额外的气味，以通过气味帮助检测。LPG是石油和橡胶产品的绝佳溶剂，通常对钢和铜合金不腐蚀。

液化石油气制冷周期

（1）。LPG气缸：

从LPG气缸中，LPG流过管道并到达毛细管。LPG气压约为80-100 psi。

(2). Capillary Tube:
As the capillary tube, capillary tube downs the pressure up to less then 1 psi.

（3）。蒸发器：
在蒸发器液化石油气转化成蒸汽from with low pressure. After passing through the evaporator low pressure and temperature LPG vapour absorbs heat from the chamber system.

（4）。煤气灶：
执行冷却效果后，低压LPG气体进入燃烧的燃烧器。

WORKING LPG REFRIGERATOR

液化石油气制冷背后的基本思想是使用液化石油气的蒸发来吸收热量。LPG制冷工作的简单机制如图所示。

» LPG is stored in the LPG cylinder under high pressure. When the gas tank of regulators is opened then high pressure LPG passes in gas pipe. This LPG is going by high pressure gas pipe in capillary tube.

»高压LPG在毛细管下以焓保持恒定的低压转换。

» After capillary tube, low pressure LPG is passed through evaporator. LPG is converted into low pressure and temperature vapour from and passing through the evaporator which absorbs heat from the chamber. Thus the camber becomes cools down. Thus we can achieve cooling effect in refrigerator.

» After passing through the evaporator low pressure LPG is passed through pipe by burner. And we can uses the low pressure of LPG is burning processes.

液化石油气制冷的优势

»LPG的冷却能力比R-12高10％，蒸气压很合适。
» LPG is naturally occurring and non-toxic.
»将LPG用作制冷剂还将整体效率提高10％至20％。
»LPG的臭氧耗竭潜力（ODP）为0，与其他制冷剂相比，全球变暖电位（GWP）为8，这显着可忽略不计。
» Apart from environment friendly, use of also LPG gives us lot of cost advantages.
»LPG不形成酸，从而消除了毛细血管阻塞的问题。
» There is 60% reduction in weight of the system due to higher density of LPG.
» The fridge works when electricity off.
» It is efficient to save fuel.
»没有污染
»单元在操作中有效地保持沉默。
»运行成本为零。
» Eliminates the compressor and condenser.

DISADVANTAGES OF LPG REFRIGERATION

»LPG本质上是爆炸性的。
» Do not maintain constant pressure in LPG cylinder.
» Put the LPG cylinder is inverted position.
»制冷过程后，液化石油气的排气被燃烧成燃烧器。由于耗尽的蒸气，LPG无法再次转换液相，因为该过程非常昂贵。
» The prevention of leakage of the LPG is the major problem in LPG refrigeration system. Because of the LPG is highly flammable.

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LPG制冷系统的设计和制造报告PDF下载