12V Air Conditioner Using Pelliter Module

ABSTRACT

This project demonstrates an environmental friendly methodology for construction an air conditioning system. In particular, the cooler does not deplete the earth’s limited fossil fuel reserves nor does it harm the global environment either by depleting stratospheric ozone or by contributing to global warming through the emission of greenhouse gases. The electrical energy input needed to power the cooler is supplied 12v dc. The air-conditioning based on thermoelectricity may play an important role despite a lower cooling performance compared with gas compression cycles. With the usual arrangement of a heat sink on each side of the Peltier device, air would be directed away on the hot side and forward on the cool side, thus cooling the surrounding area. The proposed model is verified using appropriated hardware, where the results are found to be satisfactory.

 CHAPTER ONE

1.0                                                        INTRODUCTION

A 12v Air conditioning is the process of altering the properties of air to more comfortable conditions, typically with the aim of distributing the conditioned air to an occupied space such as a building or a vehicle to improve thermal comfort and indoor air quality. In common use, an air conditioner is a device that lowers the air temperature. The cooling is typically achieved through a refrigeration cycle, but sometimes evaporation or free cooling is used. Air conditioning systems can also be made based on desiccants. This dc air conditioner is designed using peltier module.

Thermoelectric cooling of this deviceuses the Peltier effect to create a heat flux between the junction of two different types of materials. A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the device to the other, with consumption of electrical energy, depending on the direction of the current. Such an instrument is also called a Peltier device, Peltier heat pump, solid state refrigerator, or thermoelectric cooler (TEC). It can be used either for heating or for cooling, although in practice the main application is cooling. It can also be used as a temperature controller that either heats or cools.

This technology is far less commonly applied to refrigeration than vapor-compression refrigeration is. The primary advantages of a Peltier cooler compared to a vapor-compression refrigerator are its lack of moving parts or circulating liquid, very long life, invulnerability to leaks, small size, and flexible shape. Its main disadvantages are high cost and poor power efficiency. Many researchers and companies are trying to develop Peltier coolers that are both cheap and efficient.

• BACKGROUND OF THE PROJECT

In 1834, Jean Peltier discovered that by passing a current through two dissimilar conductors, the junction of those materials will either absorb or release heat, depending on the direction of the current flow. Thirteen years earlier, Thomas Seebeck had discovered current would flow when you placed a temperature gradient across the junction of two dissimilar metals. These two discoveries were the basis of thermoelectrics. With the advent of modern semiconductors, thermoelectric devices became practical for real world applications and are now found in everything from consumer goods to spacecraft.

1.2                                 OBJECTIVE OF THE PROJECT

The objective of this work is to provide a new air conditioning apparatus for automotive application, which refrigeration systems is based on the Peltier Effect, replacing the “old ” compression gas system and providing higher efficiency, more reliability and a lower cost of assemblage and maintenance.

Other objective of this work is to provide an electronic control panel operated by the driver and passengers on the vehicle, allowing them to choose the desired temperature of the air provided by the new air conditioning apparatus.

All the devices constructed using the new system don’t have any movable parts using thermoelectric cells, and are lighter and smaller than traditional air conditioning apparatus.

1.3                                         SIGNIFICANCE OF THE PROJECT

peltier module used in this work have no moving parts and do not require the use of chlorofluorocarbons. Therefore they are safe for the environment, inherently reliable, and virtually maintenance free. They can be operated in any orientation and are ideal for cooling devices that might be sensitive to mechanical vibration. Their compact size also makes them ideal for applications that are size or weight limited where even the smallest compressor would have excess capacity. Their ability to heat and cool by a simple reversal of current flow is useful for applications where both heating and cooling is necessary or where precise temperature control is critical.

1.4                                          APPLICATION OF THE PROJECT

Air conditioners are used for the most demanding industries such as medical, laboratory, aerospace, semiconductor, telecom, industrial, and consumer. Uses range from simple food and beverage coolers for an afternoon picnic to extremely sophisticated temperature control systems in missiles and space vehicles.

Air conditioners permit lowering the temperature of an object below ambient as well as stabilizing the temperature of objects above ambient temperatures. A 12v Air conditioners using peltier module is different from a heat sink because it provides active cooling unlike a heat sink which provides only passive cooling.

This system can be used for applications that require heat removal ranging from milli-watts up to several thousand watts. However, there is a general axiom in thermoelectrics: the smaller the better. This system makes the most sense when used in applications where even the smallest vapor compressor system would provide much more cooling than necessary. In these situations, a thermoelectric cooler can provide a solution that is smaller, weighs less, and is more reliable than a comparatively small compressor system.

However, the trend in recent years has been for larger and larger thermoelectric systems. As power supplies become less expensive this has driven the cost of a complete thermoelectric system (cooler, power supply, and temperature controller) lower, so higher power systems are now more marketable. Systems with capacities in the 200-400 watt range are becoming more common, although they are still not nearly as common as smaller systems where the cooling capacity is below 100 watts.

Large thermoelectric systems in the kilo-watt range have been built for specialized applications such as cooling within submarines and railroad cars or cooling process baths in specialized areas such as in semiconductor manufacturing. In cases where thermoelectric coolers are used for such large applications there generally has been a good reason why a vapor compressor system has not been used (for example, vibration needs to be minimized or precision temperature control is required). In which case, the extra cost and higher power consumption of the thermoelectric cooler can be justified.