1. IS 1391: Air Conditioning Specification College of Engineering Pune (COEP) Forerunners in Technical Education 1

2. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Introduction 2 IS 1391 (Part 1) : 1992 Room air conditioners - Specification: Part 1 Unitary air conditioners IS 1391 (Part 2) : 1992 Room air conditioners - Specification: Part 2 Split air conditioners IS1391 standard prescribes the constructional and performance requirements of split air conditioners. This also used for prescribes the test conditions and the corresponding test procedures for determining various performance characteristics of the split air conditioners at standard rating conditions. This standard specifies split air conditioners which may also serve as heaters by heat pump or electric heater applications.

3. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Split Air Conditioner 3 The split air conditioner comprises of two parts: The outdoor unit, fitted outside the room, houses components like the compressor, condenser and expansion valve. The indoor unit comprises the evaporator or cooling coil and the cooling fan. Since, except the cooling fan all the noise producing devices are placed in the outdoor unit, split air conditioners operates at very low noise levels.

4. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT 4 Split Air Conditioner 1ON/OFF Indicator2Temperature Indicator 3Panel Frame4Chasis 5Front Panel6Horizontal Louver 7Vertical Louver8Air Filter 9Manual Control10Stand 11Connecting Pipe12Drain Hose 13Remote Control

5. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Classification of Split Air Conditioner 5 According to function and nominal cooling capacity, split air conditioners shall be classified as follows. 1. Classification by Function: a)Cooling and Dehumidification: b)Cooling and Heating by Heat Pump c)Cooling and Heating by Electric Heater 2. Unit Type a)Single Split having Single Indoor and Outdoor Unit b)Multi Split having Multiple Indoor and Single Outdoor Unit 3. Unit Mounting Arrangements a)Floor Type b) Ceiling Type c) Wall Type 4. Unit Cooling Capacity: 3000, 4500, 6000, 7500 and 9000 kcal/h.

6. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT 6 Test Conditions Types of Test ConditionsRoom air temperatureOutside air temperature DBT( o C)WBT( o C)DBT( o C)WBT( o C) Capacity Rating27193530 Maximum Operation35244627 Freeze-Up Test21162116 Enclosure Sweat Test27242724 Heating by Heat Pump Capacity 21-76 Heating by Heat Pump Overload Rating 24-2115.5

7. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT 7 Capacity Rating Test The purpose of the capacity rating test is to determine the magnitude of the following functions: 1.Net total cooling effect 2.Net dehumidifying effect 3.Net sensible cooling effect 4.Net total air capacity for cooling Procedure of capacity rating test Calorimeter test room is required. Test conditions shall be maintain until equilibrium has been reached. Condition maintained 1 hours before the recording data.

8. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT 8 Capacity Rating Test The test shall then be run for 1 hour recording data every 10 minutes, giving 7 sets of readings. The test should be conducted at the selected conditions with no changes in fan speed or system resistance made to correct the variations from the standard barometric pressure. Power consumption also determine in this method.

9. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT 9 Maximum Operating Conditions Test The purpose of this test is to prove that the air conditioner is capable of operating satisfactorily under maximum operating conditions. The split air conditioner shall be operated continuously for 2 hours without tripping of the motor after the specified air temperatures and equilibrium condensate level have been established. All power to the split air conditioner shall then be cut off for 3 minutes and then restored for 1 hour. During this test no water should be sprinkled on to the condenser other than what is condensed in the evaporator. The motor overloaded device may trip only during the first 5 minutes after shut down period of 3 minutes.

10. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Freeze-Up Tests 10 The air blockage test and the drip test shall be conducted to determine the ability of the air conditioner to operate satisfactorily under conditions with the maximum tendency to frost or ice the evaporator. 1) Air Blockage Test: The test should be continuous, with the unit on the cooling cycle for 12 hours after establishment of the specified temperature conditions. 2) Drip Test: The unit should be operated for 6 hours with room side air inlet covered to completely block the passage of air so as blockage of the evaporator coil by frost. After that unit should be stop for complete melting of frost. Then unit should turn on again for 5 min.

11. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Enclosure Sweat Test 11 The purpose of this test is to determine the resistance to sweating of the air conditioner when operating under conditions of high humidity. After establishment of the specified temperature conditions, the unit shall be operated continuously for a period of 4 hours. During the test, no condensed water shall drip, run or blow off the unit.

12. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Calorimeters 12 Calorimeter required for testing split air conditioners. Air conditioners cooling capacity tested in room calorimeters. There are two types of calorimeters. 1)Calibrated room calorimeters 2) Balanced ambient room calorimeters The room side capacity determination is made by balancing the cooling and dehumidifying effects with measured heat and water inputs. The outdoor side capacity provides a conforming test of the cooling and dehumidifying effect by balancing the heat and water rejection on the condenser side with a measured amount of cooling medium.

13. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT 13 Calorimeter Working Principle Indoor Unit Heating Humidifier Measuring Instrument Indoor Side Outdoor Unit Heating Measuring Instrument Dehumidifier Outdoor Side Cooling and Dehumidification Heating and Humidification

14. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNI 14 Calibrated Room Calorimeters

15. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT 15 Balanced Ambient Room Calorimeters

16. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Construction of Calorimeter 16 The two calorimeters compartments, room side and outdoor side, are separated by an insulated partition having an opening into which the split air conditioner is mounted. A pressure equalizing device shall be provided in the partition wall between the room side and the outdoor side compartments to maintain a balanced pressure between these compartments and also to permit measurement of leakage, exhaust and ventilation air. A pressure equalizing device also measure leakage, exhaust and ventilation air. The equalizing device shall be adjusted during calorimeter tests, so that the static pressure difference between the room side and outdoor side is not greater than 1.5 N/m 2.

17. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT 17 Construction of Calorimeter The size of the calorimeter shall be sufficient to avoid any restriction to intake or discharge openings of the air conditioner. Maximum Rated Cooling Capacity Kcal/h (W) Minimum Inside Dimensions of Each Room of Calorimeter Width (m)Height (m)Depth (m) 2500 (3000)2.42.11.8 5000 (6000)2.42.12.4 7500 (9000)2.72.43.0

18. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT 18 Calculation For Capacity Rating 1)Total Cooling Capacity Effect: Q tr = ΣE r + (h w1 – h w2 ) w r + q lp + q lr Q tr = total room cooling effect as determined on room side compartment, in watts; ΣE r = sum of all power input to room side compartment, in watts; h w1 = specific enthalpy of water or steam supplied to maintain humidity. h w2 = specific enthalpy of condensed moisture leaving the room side compartment. w r = water vapour (rate) condensed by air conditioner. q lp = heat leakage rate into room side compartment through separating partition between room side and outdoor side compartments. q lr = heat leakage rate into room side compartment through wall, floor and ceiling.

19. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Calculation For Capacity Rating 19 2) Total Cooling Effect on Outdoor Side Q to = Q o – ΣE o – E + (h w3 – h w2 ) w r + q lp + q 1o Q to = Total room cooling effect as determined on outdoor side, in watts Q o = Heat removed by cooling coil in outdoor side compartment, watts ΣE o = Sum of all power input to any equipment, such as reheaters circulating fans, etc, in outdoor side compartment, in watts E = Total power input to air conditioner, in watts h w2 = Specific enthalpy of condensed moisture leaving the room side compartment h w3 = Specific enthalpy of condensate removed by air-treating coil in outdoor side compartment w r = water vapour condensed by air conditioner q lp = heat leakage out of outdoor side compartment through separating partition between room side and outdoor side compartments.

20. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT 20 Calculation For Capacity Rating 3) Net Room Dehumidifying Effect: Q d = K 2 * w r Q d = net room dehumidifying effect in watts; K 2 = 2 460 kJ/kg w r = water vapour condensed by air conditioner 4) Net Room Sensible Cooling Effect Q s = Q tr – Q d Q s = Net Room Sensible Cooling Effect

21. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Instruments 21 1.Temperature Measuring Instruments: Temperature measurements shall be made with one or more of the following instruments: a) Mercury-in-glass thermometers, b) Thermocouples, c) Electric resistance thermometers, and d) Electronic temperature indicator. Instrument accuracy shall be within the following limits: a) Wet bulb and dry bulb temperatures of reconditioned air in room side calorimeter compartment, ±0.1 0 C. b) Water temperatures, outdoor side compartment conditioning coil, ±0.1 0 C. c) All other temperatures, ±0.3 0 C.

22. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Instrument 22 2. Pressure Measuring Instruments Accuracy of pressure measuring instruments, not including barometers should permit measurements within ±1 N/m 2 (0.01 m bar) (0.1 mm H 2 O). Barometric pressure shall be measured by a barometer having scale markings permitting readings with an accuracy within ± 0.1 percent. 3. Electrical Instruments Instruments used for measuring all electrical inputs to the calorimeter compartments shall be accurate to ± 0.5 percent of the quantity measured.

23. College of Engineering Pune (COEP) Forerunners in Technical Education INDOOR UNIT Instruments 23 4. Water Flow Measuring Instruments: Volume measurements shall be made with either of the following instruments having an accuracy of ± 0.1 percent of the quantity measured: a) Liquid-quantity meter, measuring either mass or volume. b) Liquid flow rate meter. 5. Noise Measuring Instrument Noise measurement shall be made with a sound level meter whose accuracy is ± 0.1 percent of the quantity measured. The instrument shall be able to measure a weighted sound pressure level.