Car Air condition cycle Presentation Present to / Pro. Dr. Saad Abd El hamid Car Air condition cycle Presentation Present from : -1رنـــــــا السيد العربي غريب -2سمر حامد أبو الفتوح صيـــــام -3خـــلود علي علي المرسى -4نسمة محمد حافظ عبد هللا المقدم -5مروة متولي عبد المطلب الشيخ Components of cycle 1-compressor 2-condenser 3-evaporator 4-thermal expansion valve 5-receiver-drier 6-blower 7-thermostate compressor compressor Commonly referred to as the heart of the system, the compressor is a belt driven pump that is fastened to the engine. It is responsible for compressing and transferring refrigerant gas. The A/C system is split into two sides, a high pressure side and a low pressure side; defined as discharge and suction. Since the compressor is basically a pump, it must have an intake side and a discharge side. The intake, or suction side, draws in refrigerant gas from the outlet of the evaporator. In some cases it does this via the accumulator. Once the refrigerant is drawn into the suction side, it is compressed and sent to the condenser, where it can then transfer the heat that is absorbed from the inside of the vehicle. condenser Condenser condenser This is the area in which heat dissipation occurs. The condenser, in many cases, will have much the same appearance as the radiator in you car as the two have very similar functions. The condenser is designed to radiate heat. Its location is usually in front of the radiator, but in some cases , due to aerodynamic improvements to the body of a vehicle, its location may differ. Condensers must have good air flow anytime the system is in operation. On rear wheel drive vehicles, this is usually accomplished by taking advantage of your existing engine's cooling fan. On front wheel drive vehicles, condenser air flow is supplemented with one or more electric cooling fan(s). As hot compressed gasses are introduced into the top of the condenser, they are cooled off. As the gas cools, it condenses and exits the bottom of the condenser as a high pressure liquid. evaporator evaporator Located inside the vehicle, the evaporator serves as the heat absorption component. The evaporator provides several functions. Its primary duty is to remove heat from the inside of your vehicle. A secondary benefit is dehumidification. As warmer air travels through the aluminum fins of the cooler evaporator coil, the moisture contained in the air condenses on its surface. Dust and pollen passing through stick to its wet surfaces and drain off to the outside. On humid days you may have seen this as water dripping from the bottom of your vehicle. Rest assured this is perfectly normal. Thermal expansion valve thermal expansion valve Another common refrigerant regulator is the thermal expansion valve, or TXV. Commonly used on import and aftermarket systems. This type of valve can sense both temperature and pressure, and is very efficient at regulating refrigerant flow to the evaporator. Receiver-drier receiver-drier The receiver-drier is used on the high side of systems that use a thermal expansion valve. This type of metering valve requires liquid refrigerant. To ensure that the valve gets liquid refrigerant, a receiver is used. The primary function of the receiver-drier is to separate gas and liquid. The secondary purpose is to remove moisture and filter out dirt. The receiver-drier usually has a sight glass in the top. Thermostat thermostat A thermostat is a device for regulating the temperature of a system so that the system's temperature is maintained near a desired set point temperature. How A/C WORKS? Air conditioning facilitates the removal of heat from inside the vehicle. The principle applied is that heat is removed by conduction and convection. An evaporator which is cold absorbs the heat from the air that is passed through it and then cold air is forced out through the vents inside the car by the blower motor. This is done by pressurizing refrigerant (134a) with a compressor and then releasing refrigerant (134a) inside the air conditioner evaporator Some automobiles are equipped with an automatic climate control system to regulate the temperature inside the car automatically. The climate control module is a computer which monitors and adjusts to a temperature set by the user. The temperature is controlled by a combination of cold air from the air conditioner, and hot air from the heater to achieve a desired temperature. The blower motor speed is controlled by a solid state speed controller. This controller electrically controls the speed of the blower motor and replaces the conventional blower motor resistor system. The air conditioning and heating unit provides thermal comfort to passengers inside no matter what the temperature is outside. The air inside can be heated, cooled, disinfected or ventilated. The climate control feature helps to maintain the desired temperature. The system that provides cooling, heating and climate control is known as the HVAC (heating, ventilation, air conditioning) system. Basic principles of fluid mechanics, thermodynamics and heat transfer provide cold and heat for the particular system. Your climate control settings allow all three to work together to achieve good indoor air quality, thermal comfort and optimal pressure. The climate control system can store trouble codes when a problem is detected in the system. You can retrieve codes by pressing two or more buttons on the control panel at the same time. To find out how to retrieve trouble codes for you vehicle check your owner's manual or consult a repair manual. When the code retrieval system is enabled a trouble code will appear on the temperature control head. After repairs have been made the system will need to be re-enabled this is done by disconnecting the battery for 45 seconds and reconnecting the battery. Testing can be aborted at anytime by turning the key to the off.