Air Conditioning Filter

Transcription

1 Air Conditioning Filter Air conditioning filter in the house or offices is used to remove solid contaminants such as smoke, pollen, dust, grease and pollen to ensure better air quality for the occupants. A study showed that indoor pollution is common these days due to the chemicals that are used in household furnishings and various goods. These filters are usually placed on the return air of the air conditioning system. The air that contained the contaminants are trapped here. Clean air is then discharged into the space together with the cool air. Types of Air Conditioning Filter Plastic mesh filters are commonly installed at the return air of most indoor unit of room or window air conditioner. They trapped bigger particles of dust and should be cleaned every two weeks and more frequent if the space being conditioned is polluted. If you look at the manual, they are easy to take out from the unit. Wash thoroughly with water and household dish washing detergent to remove dirt that stuck to it. Leave to dry and put back. An air filter on display during one of the HVAC exhibition.

2 These simple steps of cleaning help to ensure the efficiency of the unit and hence save electricity as well besides providing a cleaner air space for you. Electrostatic air filters are commonly placed in the return air of the air conditioner unit where the air is subjected to high voltage up to 12kV between two plates. The ionized particles are then drawn to the grounded plates. The electronic circuit used to generate the voltage is usually embedded on the control printed circuit board or a separate module. Carbon and Adhesive filters are other types used. Carbon type is made of activated carbon that is effective in removing odour causing gases and bacteria. Adhesive type is made of cotton and fiber glass material coated with adhesive oil or liquid which trapped the particles. Solid Contaminants The sizes of contaminants that exists in our air ranges from 0.01 microns to 10,000 microns. Virus, oil smoke, fumes and suspended impurities have sizes ranges from 0.01 to 1 microns. Mold, pollen, fog, dust, mists and ashes ranges from 1 to 100 microns. Dust emitted from heavy industry factories is about 100 to 10,000 microns. Filter Rating The ability of the filters to trap particles is measured by using the industry standard known as MERV or Minimum Efficiency Reporting Value. The values ranges from 1 to 20 and can trap particles sizes from 0.3 microns to 10 microns. The higher the value, the better it is able to trap smaller particles. Residential applications usually ranges from 1 to 12 with MERV 12 able to trap particles from 1 to 3 microns. Highly specialized applications such as clean room and surgery room use MERV 16 to MERV 20. Condensate Pump What is a condensate pump? In HVAC or refrigeration process, the water that condenses i.e. condensate, need to be channeled out from the building to proper drainage outside the building. The condensation process usually

3 occurred when the air passes though the cold evaporator coil during the cooling process. As a result, the moisture that accumulate on the coil then drip down into the drain pan that is placed underneath the coils. Systems that are able to use the gravitational force to flow the water that accumulate on the drain pan does not require the use of the pump. However, there are many instances when the air conditioning systems require to use of this pump to get the water out to prevent the water from dripping into the space. The condensate pump that is used in residential system is usually low power (approximately 60W) and simple in function. However, regular inspection of this unit is critical as you do not want to have to come back to your house with water dripping all over your carpet, furniture or electrical goods. It is always a good idea to find out whether your air conditioner is using the pump in its operation. Generally, the condensate pump has the following specifications and functions that you should know: Float Switch is an input that is used whether to energize the pump or otherwise. When the water accumulate on the tank reaches the level set on the float switch, it will trigger a signal to operate the pump until the water or liquid is reduced substantially. Once this happens, the pump will stop operating. Tanks of the pumps usually range from 0.5 to 1 gallon or 2 to 4 litres. Smaller pump may not have any tank but is placed directly on the drain pan to pump the condensate water out of the pan. Choosing a Condensate Pump Take note of the following before buying the pump for replacement. Look for UL and CSA marking on the pump. These certification is important to ensure that the pump is designed and produced for safety according to the industry standards. A Thermal Overload protection is an added feature that shuts down the pump motor in the event of overheating, thus protecting the pump from damage or fire hazard.

4 If a tank is required, look for one with high impact ABS tank material as well as leak-proof and rustproof design. Stainless Steel Shaft helps to prolong the life of the pump. A removable Check Valve option to prevent the water from flowing back into the tank in the event that the outlet line is at a higher level than the tank. Power cord and plug that are long enough for your application. A safety switch will be good as an output that can be connected to trigger an alarm when overflows happen. This output can also be used to shut down the air conditioning system to prevent further damage to the system. In temperate countries, it is critical that the condensate water that goes out through the piping is totally drain out especially during winter. This is important because the water that is not drained out will freeze and may crack the piping or cause improper functioning of the system. Condenser Function of Condenser In a cooling cycle of a refrigeration system, heat is absorbed by the vapor refrigerant in the evaporator followed by the compression of the refrigerant by the compressor. The high pressure and high temperature state of the vapor refrigerant is then converted to liquid at the cond. It is designed to condense effectively the compressed refrigerant vapor. There are basically three types of condensing unit depending on how the heat is removed by the condensing medium which is usually water, air or a combination of both. Air-Cooled types are usually used in the residential and small offices applications. They are used in small capacity systems below 20 tons. The advantages of using this design include not having to do water piping,

5 not necessary to have water disposal system, saving in water costs and not much scaling problems caused by the mineral content of the water. It is also easier to install and has lower initial cost. There isn't much maintenance problems. The disadvantages are that it requires higher power per ton of refrigeration, has shorter compressor life and on days when most cooling is required, the least is available. A condensing unit that contains finned coils, fan and compressor. The circulation of air-cooled type can be by natural convection or by forced convection (usually using blower or fan). Due to its limited capacity, natural convection is used in smaller applications such as freezers and refrigerators. In forced convection, air is circulated by using a fan or blower that pulls the atmospheric air through the finned coils. Internally, the refrigerant circulates through the coil and air flows across the outside of the tubes. Water-Cooled There are 3 types commonly being used. They are shell and tube, shell and coil, and double tube. The most commonly used is the shell and tube type and are usually available from two tons up to couple of hundred tons. This design has lower power requirements per ton of refrigeration and the compressors can last longer compared to the air-cooled type. A water cooling tower is frequently used for higher capacity application. Evaporative type which is a combination of water and air-cooled.

6 Air-Cooled and Water-Cooled Comparison Summary Air-cooled type operates at higher head pressure or condensing pressure, hence reducing the capacity of the compressor and increases the power intake. In general, a 2 hp water-cooled system will require the same refrigeration as a 3 hp air-cooled system. The maintenance costs of water-cooled type is about three to four times the air-cooled type. Air-cooled type maintenance is usually limited to regular lubrication of fan and motor bearings. Water-cooled type requires cleaning from algae and bacteria. Scales on the tubes are removed by using acid compound. Proper water treatment is also critical to the operation of the condenser. Air Conditioner Compressor Air conditioner compressor is used to remove the heat-laden vapor refrigerant from the evaporator of the air conditioning systems. In layman term, the compressor compresses or squeezes the vapor into a smaller volume at high temperature. The external-drive compressor has a crankshaft that is driven by a pulley and belt system. An electric motor can also be used to drive it directly. The hermetic compressor has a motor which is sealed inside a housing with the compressor, hence a crankshaft seal is not required. The motor rotor is located either at the top or bottom of the unit. There are basically 5 types of air conditioner compressor that are commonly used in the HVAC industry: Reciprocating Scroll Screw Rotary Centrifugal

7 A Compressor Reciprocating Air Conditioner Compressor The reciprocating compressor uses piston to compressor the refrigerant driven by a crankshaft in a straight line back and forth motion. This rotary motion is achieved by the use of an electric motor and the construction is quite similar to that of an automobile engine. The piston moves up and down inside a cylinder. Vapor from the suction line is moved through the intake valve as the piston move downward. As the piston moves upward, it compresses the vapor refrigerant which is then pushed through the exhaust valve into the condenser. The compressor may has more than one cylinder which is also known as multicylinder compressor. The common ones are the two-cylinder, four-cylinder and eight-cylinder compressors Scroll A scroll compressor has one fixed scroll which remains stationary and another moving or orbiting scroll that rotates through the use of swing link. When this happens, the pockets of refrigerant between the two scrolls are slowly pushed to the center of the two scrolls causing the reduction of the volume of the gas. It is then discharged though the center port to the condenser.

8 The advantage of scroll compressor is that it has fewer moving parts and less torque variation compared to the reciprocating compressor. This advantage is translated to a smooth and quiet operation. The scroll compressor is also known as scroll pump or scroll vacuum pump. Screw The screw compressor uses a pair of helical rotors where it traps and compresses the gas as the rotors revolve in the cylinder. In HVAC, they are usually used in systems with 20 ton capacity and above. The male rotor and the female rotor are built inside the cylinder. The low pressure refrigerant enters one end of the compressor and the resultant high pressure refrigerant is discharged into the opposite end to the condenser. Rotary The rotary compressor can be divided into two types. One has blades or vanes that rotate with the shaft. The other type has the blade which remains stationary and is part of the compressor housing assembly. In both types, the vapor from the suction line is drawn into the cylinder through the suction port. As the blade rotates, trapped vapor in the space ahead of the blade is compressed into high pressure gas after which it is discharged to the condenser through the exhaust port. The number of blades can range from two to eight in a single system. Centrifugal Centrifugal compressor is usually used in large capacity refrigerating system. In this compressor, the vapor is moved in a circular motion known as centrifugal force. An impeller which is a disk with radial blades spins rapidly inside this housing causing the gas to gain velocity. A diffuser converts this energy into pressure energy and is then discharged into the condenser. The pumping efficiency increases with speed, hence this type of compressors are designed to operate at high speed. The main advantage of centrifugal compressor is that there are no valves, pistons or cylinders. The wearing parts that need attention are the main bearings.

9 Evaporator Evaporator is an important component together with other major components in a refrigeration system such as compressor, condenser and expansion device. The reason for refrigeration is to remove heat from air, water or other substance. It is here that the liquid refrigerant is expanded and evaporated. It acts as a heat exchanger that transfers heat from the substance being cooled to a boiling temperature. There are two types of evap.: Forced Convection Type uses a fan or pump to force the liquid being cooled over the evap. Natural Convection Type has the liquid being cooled flows naturally to the evap. due to the density differences of the chilled and warm liquid. Construction Types There are three types of evap. construction that are commonly being used today: Bare-Tube and Plate Surface construction have the entire surface in contact with the evaporating refrigerant inside. Finned construction are bare-tube coils upon which fins (metal plates usually Aluminium) are being installed. A more detailed discussion on this type of design will be provided here.

10 An indoor unit that contains finned evap. Finned Evap. The fins are added to the bare-tube to increase the heat transfer capability. They act as heat collector that pick up heat from the surrounding air and conduct it to the refrigerant inside the tube hence improving the efficiency in cooling the air of the surrounding. They are best used in the air-cooling space where the temperature is around 34 F. Having fins mean the surface area for heat transfer has been extended. This means that the finned coils can have more compact in design compared to the bare-tube type of similar capacity. In summary, finned coils help to reduce coil cost, size and weight. Thermal Contact and Fin Spacing Good thermal contact between the fins and tubes is a must to ensure efficient heat transfer. They can be soldered together. The other more practical method is to expand the fins by pressure such that they bite into the tube surface hence a good thermal contact is established. The spacing of the fin depend on the operating temperature of the coil. Low temperature application uses only 1 fin. In air conditioning application, fins per inch may be used as long it is designed in such a way that frost does not accumulates in the coils. Excessive finning may reduce the capacity of the evap. by restricting the flow of air over

11 the coil hence the design engineers must do a proper system calculation and simulation at design stage. Evaporator Design Factors There are 3 main factors to consider in designing an evap. Pressure Drop The evap. must have sufficient space for the circulation of the refrigerant without too much pressure drop between the outlet and the inlet. Temperature The evap. must have enough surface to absorb the required heat load in order to ensure the temperature difference between the substance being cooled and the refrigerant is not excessive. Liquid and Refrigerant Vapor The evap. must have enough space for the liquid refrigerant and the vapor to separate from the liquid. Expansion Valves Expansion valves are devices used to control the refrigerant flow in a refrigeration system. They help to facilitate the change of higher pressure of liquid refrigerant in the condensing unit to lower pressure gas refrigerant in the evaporator. The term "low side" is used to indicate the part of the system that operates under low pressure, in this case the evaporator. The "high side" is used to indicate the part of the system that operates under high pressure, in this case the condenser.

12 Types of Expansion Valves There are basically four types of valves that are in used. These valves are also refer to as metering devices. Automatic Exp. Valves Thermostatic Exp. Valves Capillary Tubes Float Valves Automatic Expansion Valve regulates the flow of refrigerant from the liquid line to the evaporator by using a pressure-actuated diaphragm. It maintains a constant pressure in the evaporator. The setback is that it is not efficient if the load fluctuates hence this type is not suitable for use in air conditioning as the load fluctuates a lot during its operation. Thermostatic Expansion Valve uses a valve mechanism to control the flow of liquid refrigerant into the evaporator coil. The flow is controlled by the pressure in the evaporator. This type of metering device is able to operate well when the load fluctuates and hence is suitable for use in air conditioning system. When the evaporator warms, the valve provides a higher flow rate and when it cools, it reduces the flow rate. It is also commonly refer to as TXV, TEV or TX valve. There is a sensing bulb which detects the temperature of the coil and is usually located at a higher temperature within the evaporator. The bulb must be clamped firmly to the coil to ensure proper sensing. When the temperature of the evaporator increases due to the demand for cooling, the pressure in the bulb will also increase hence pushing the spring to open the valve. Similarly, when the temperature of the evaporator reduces due to a lack of demand for cooling, the pressure in the bulb will drop hence causing the spring to close the valve. Capillary Tube is a tube with small internal diameter and could be coiled for part of its length. It is installed to the suction line. A filter-drier is sometimes fitted before the tube to remove dirt or moisture from the refrigerant. This device is simple, does not have any moving part and lasts longer. In order to use this device, the amount of refrigerant in the system must be properly calibrated at factory level. Due to its lower cost compared to TXV, this metering device is used in units that are produced in large quantity such as room or window air conditioners.

13 Depending on the capacity design of the system, the capillary tube internal diameter that is commonly used range from 0.031" to 0.065" and the outer diameter from 0.083" to 0.130". Float Valve is actuated by a float that is immersed in the liquid refrigerant. Both low-side float and high side-float are used to control the flow of liquid refrigerant. The low-side float helps to maintain a constant level of liquid refrigerant in the evaporator. It opens when there is no liquid in the evap. and closes when there is liquid in the evap. The high-side float is located at the high pressure side of the system and maintain a constant level of refrigerant in the condenser. When the compressor operates, the condensed refrigerant flows to the float chamber and opens the valve. This causes the refrigerant to flow into the evaporator where it is stored. As the liquid level falls in the float chamber, the valve opening will close hence preventing the liquid from flowing to the evap. Thermal Insulation Thermal insulation in air conditioning system is primarily used to reduce heat gain or heat loss from piping. Other factors include preventing the icing of water vapor and condensation on cold surface. Water vapor from the air or surrounding area must be kept from entering the cold side of the pipe to prevent condensation of moisture from the air on the outside of the cold piping. Condensation can cause damage to surrounding areas such as carpet or other furnishing. Hence, the insulation must also acts as a vapor barrier.

14 Insulation material for HVAC applications. It also helps to reduce the noise level, absorb the vibration generated by the system, prevent the spread of fire and adding structural strength to the walls or ceilings. Well-chosen material can also protects the piping being insulated from harsh environmental conditions such as UV light, salt, water, dusts, chemicals and oil. Other characteristics may include the ability to inhibit the growth or viruses, bacteria and fungi. Insulation Characteristics Low thermal conductivity. Reasonable strength Non-com combustible. Resistance to Fungi such as one that is based on ASTM G21 standard. Excellent resistance to ozone Excellent resistance to UV. Does not deteriorate or rot over time.

15 Pipe insulation materials can be manufactured from rubber, wool, glass fibers or cork. The polyurethane or P.U. is a synthetic material that is commonly used these days due to its low thermal conductivity and other good properties. Air conditioning insulation material. Location of Insulation in Cooling System Cold Line is insulated to prevent any air leakage into the insulation that can cause condensation of moisture in the pipe. Suction Line is insulated to prevent the loss of capacity or sweating due to heat gain. Heat gain causes extra load to the condenser hence reducing the overall capacity of the air conditioning system. Liquid Line does not require any insulation as it is at a higher temperature than the surrounding air. Heat loss to the surrounding air is desirable as it improves the system capacity. Discharge Line does not require insulation because loss of heat removes load from the condenser. This helps to improve the performance of the compressor.

16 Air Conditioner Motors Air conditioner motors are some of the crucial components that are required in the operation of the air conditioning in your house. We will discuss the various types of single-phase motors that are used in your equipment at home. Here are four types of electric motors that are commonly being used. Split-Phase Air Conditioner Motor This is the simplest design where the RUN winding and START winding are connected in parallel and 90 electrically apart. It is usually used in small pumps, fans and blowers where the capacity is below 1 horsepower. It has a low starting torque but high starting current. Since the torque is low, the ability to start the motor is only practical for low load condition. The RUN winding is make from bigger diameter wire and shorter turn for lower resistance and high inductance properties. The START winding is make from smaller diameter wire for higher resistance and low inductance properties.

17 When power is connected to the motor, both the windings will be energized with the current in the RUN winding lags the current in the START winding by about 30 electrically. This out-ofphase effect on the stator produces a starting torque and causes the rotor to start rotating. Typically the speed of the motor is 1800 rpm or 3600 rpm when running without any load. When the load is connected, the speed can go down to 1725 rpm and 3450 rpm respectively. The no-load speed of the motor is given by: Speed (rpm) = (Frequency of AC power X 120)/number of poles For example, if your supply is 60 Hz and the motor is using two-pole, the synchronous speed = (60X120)/= 3600 rpm There is a switch known as centrifugal switch which is connected in series with the START winding. This mechanical switch will open when the motor speed reaches 75% of the rated speed typically within 2 seconds. Once the switch opened, the START winding in circuit is disconnected. This is to protect the START winding from overheating. When the motor is powered off, the switch will close the circuit to get ready for the next starting of the motor. These days, electronic relay is also being widely used to disconnect the START winding. Capacitor-Start Air Conditioner Motor This motor is similar to the split-phase motor except that there is an external capacitor that is connected in series with the START winding. This capacitor will cause the current in the START winding to lead the voltage. The current in the RUN winding lags the voltage. When this happens, the phase difference between the two windings is 90 electrically hence a true two-phase starting is achieved.

18 The starting torque of this motor is very high making it suitable to drive small compressor which needs to start under full load. The capacity of this motor can go up to 1 horsepower. Once the motor has reached 75% of the rated speed, the capacitor and the START winding will be automatically disconnected from the circuit by using the centrifugal switch, potential or current relay. After the capacitor and START winding have been removed from the circuit, the magnetic field being generated continuously will cause the motor to continue running. This type of motor is also known as CSIR motor or Capacitor-Start-Induction-Run motor. Capacitor-Start, Capacitor-Run Air Conditioner Motor This motor design is similar to the capacitor-start design except that there is a second capacitor known as the RUN capacitor which is connected in parallel with the START capacitor and the switch. These capacitors are effectively connected in series with the START winding. During the starting of the motor, both the capacitors are connected in the circuit. The START winding and the RUN winding will remain connected to the circuit at all times.

19 Usually the capacitance of the RUN capacitor is lower than the START capacitor. During starting, the effective capacitance is the combination of both capacitors causing a greater phase angle shift between the windings. This provides a higher starting torque and can be used to drive the compressor as well as in beltdriven motors. As the rotor speed reaches 75% of the rated speed, the switch will be automatically open to disconnect the START capacitor from the circuit. The START winding remains in the circuit. The RUN capacitor helps to correct the power factor of the circuit making it more efficient. The capacity of this type of motor can go up to 10 horsepower and is one of the most efficient motors used in the HVAC industry. Permanent Split Capacitor (PSC) Air Conditioner Motor This motor has similar design to the phase-split motor except that there is a RUN capacitor connected to the START and RUN windings. This motor does not have any switch and the START winding, RUN winding and the RUN capacitor are active whenever the motor is ON.

20 This type of motor has low starting torque and is suitable to be used in small fan motors such as the fan coil unit of a split air conditioning system. Multi-speed PSC is achieved by changing the winding resistance. If high speed is required, the terminal is connected to the least winding resistance. If low speed is required, the terminal is connected to the highest winding resistance. By utilizing relays to choose the terminal to be connected to the line voltage, different speed of fan motor can be achieved. In the diagram above, there are 4 motor speed that can be selected. Super High (SH), High (H), Medium (M) and Low (L). The selection can be done by using electronic relays to connect L2 to one of the four terminals depending on the speed required.

21 Programmable Thermostat Programmable thermostat is used extensively in medium to high end HVAC systems. The common thermostat that is used in the air conditioning control system before the advancement of microchip and electronic is a simple mechanical bi-metallic thermostat that contact before a set temperature is achieved and disconnect after a set temperature is achieved. A dead band of few degrees known also as hysteresis is set to prevent chattering of contact that can cause damage to the load that is being controlled. This simple thermostat has greater tolerance and is not accurate. The tolerance can be as high as +/-5 C. The advancement and the reduction of microchip price have enabled the HVAC industry to use better electronic control that is more accurate, more user friendly and efficient. Products that incorporate Liquid crystal Display, 7 segment LED display, LED, keypad/touch screen and better industrial design have been developed. The programmable thermostats that have been certified by the government have many features that allow you to save energy. When used properly, it can save your utility bills and provide better comfort to you. If you are looking for one, make sure that the thermostat has the ENERGY STAR mark on it. Features of Programmable Thermostat 7-Da Day Programmable Schedule feature will enable you to program the ON/OFF time, temperature setting, mode of operation and other important features. This will enable the proper use of the air conditioner capacity. For instance, when there is no one at home, the set temperature will be set higher during that duration to reduce the electricity consumed. Night Setback feature will increase the set temperature (if in cooling mode) after certain hours gradually as one will not need that much

22 cooling capacity once you are sleeping. This feature is sometimes incorporated into the programmable schedule. Thermostat accuracy of +/- 2 C or better to ensure the comfort of the occupants in the house. 24 Hour Clock is a must with liquid crystal display, keypad/touch screen, backlighting that enables you to operate it in the dark. Holiday feature option need to be there. During holidays, the set temperature will be set higher (in cooling mode) or cycling mode to reduce the capacity and hence the consumption of electricity. Actual Outdoor or Indoor temperature display option is another good feature to have. Diagnostics feature that enables you to find out the reason the air conditioner is not working properly. It could be a missing sensor, high pressure tripping, low refrigerant, etc. Air Filter Change indicator after a certain time of operation. This reminder is a good feature to alert you that it is time to change or clean your filter. Installation When installing the thermostat, remember to install the sensor in a location where the air circulation is good. Usually the sensor is located at the panel itself. Do not install it under direct sunlight, doorways or windows as this will cause inaccurate reading of the room temperature.

23 Air Conditioner Refrigerant How does air conditioner refrigerant affect our environment? All of us have probably heard about the ozone layer which is located 35 miles above the ground. This upper layer of our earth's atmosphere protects the earth from the sun's ultraviolet rays by reflecting them back to space. UV rays are harmful to the plant, marine life and human beings on the earth. How does air conditioner relate to the ozone layer? It was discovered in the mid-1980s that the commonly used air conditioner refrigerant has a damaging impact on the ozone layer. At that time, the refrigerants that used then were known as CFC (chlorofluorocarbons) and HCFCs (hydro chlorofluorocarbons). CFCs are a family of chemicals that contain chlorine, fluorine and carbon. The chlorine content in these compounds cause the depletion of the ozone layer. R410A Refrigerant This discovery prompted the signing of Montreal Protocol of 1987, an agreement signed by 180 nations that target to phase out the production of CFCs by 1995 and HCFCs by New refrigerants that are being used to replace these CFCs are HFCs (hydro fluorocarbons) and refrigerant blends (Azeotropic, Zeotropic). In summary, the 4 commonly used refrigerants that you can find today are:

24 CFCs HCFCs HFCs Refrigerant blends The future commonly used refrigerants will be in the last two categories. Among the currently widely used ones are R-134a, R407C and R410A. CFC Refrigerants These refrigerants were developed more than 70 years ago and are harmful to our respiratory systems and the ozone layer. Their production was stopped since 1995 but are still being used widely in existing residential air conditioning units as many equipment have a lifetime of up to 30 years. Today's refrigerants used are from reclaimed units that are no longer in operation. The common ones still used are: R-11 CCl3F R-12 CCl2F2 R-113 CCl2FCClF2 R-114 CClF2CClF2 R-115 CClF2CF3 HCFC Refrigerants These air conditioner refrigerant is considered partially halogenated as they consists of methane or ethane in combination with chlorine and fluorine. They are shorter lifespan and are less destructive to the ozone layer compared to CFCs. They are an interim solution to a totally "free from chlorine" refrigerant that are being developed. Their production are scheduled to be phased out totally in The common ones used are: R-22 CHClF2 R-123 CHCl2CF3 R-22 is used extensively in residential, commercial and industrial applications. The schedule of phase-out: Production freeze and use limitations Prohibited for new air conditioning and refrigeration use Total phase-out

25 HFC Refrigerants These air conditioner refrigerant contain no chlorine atom and is not destructive to the ozone layer though they have a slight effect on global warming. R-134a is used in new systems that are specially designed for its use. The common HFCs are: R-134a CH2FCF3 R-125 CHF2CF3 The 1997 Kyoto Protocol puts R-134a as one of the 6 greenhouse gases that must be reduced. There is no phase-out date for this refrigerant and it is expected to be highly used in the HVAC industry. Refrigerant Blends These air conditioner refrigerant are also known as "azeotropic" and"zeotropic". Their use is increasing as they are environmental friendly. The setback is that the total air conditioning systems production cost is higher. However, as more manufacturers switch to this type of refrigerants, the cost/unit will drop eventually. The common refrigerant blends used in the air conditioning industry are: R-410A CH2F2/CHF2-CF3 R-407c R-410A are used as a replacement refrigerant for residential air conditioning applications. R-407C are used as R-22 replacement. Recovery, Recycling and Reclaiming of Refrigerants Laws have been passed to prevent the release of CFC refrigerants into the atmosphere. The steps taken are: Recovery The act of removing the refrigerant from a system and store it in an external container. No testing or processing is needed in any way.

26 Recycling Refrigerant is cleaned for reuse by oil separation and passes though devices such as core filterdriers. This procedure reduce the moisture, matter and acidity of the refrigerant for reuse. It is usually done for jobs on the field or service shops. Reclaiming Reprocess the refrigerant to new product specifications which may include distillation process. This can only be done by manufacturing plants where chemical analysis is required. Highly equipped local service shops may have this facility as well. Consumer Role How can consumer like you play your part in the effect to keep our earth green? You can do that by purchasing air conditioning systems that uses new refrigerant such as R-134a, R-407C or R- 410A. Most equipment are labelled with stickers that indicate the type of refrigerant used. Examples are "ozone friendly" sticker, "R-410A" sticker. Do your part to preserve Mother Nature...