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How does your AIR CONDITIONER work

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Language: en

00:00:00.030
air conditioners give you much-needed
00:00:02.540 00:00:02.550 thermal comfort during a scorching
00:00:04.370 00:00:04.380 summer
00:00:04.760 00:00:04.770 more specifically air conditioners help
00:00:07.490 00:00:07.500 to maintain the room temperature at the
00:00:09.350 00:00:09.360 optimum level they also help remove
00:00:12.020 00:00:12.030 airborne particles and humidity from the
00:00:14.539 00:00:14.549 room let's find out how these devices
00:00:17.240 00:00:17.250 work we want to thank dan Foss for their
00:00:19.790 00:00:19.800 support in the production of this video
00:00:21.380 00:00:21.390 you can increase your knowledge about
00:00:23.540 00:00:23.550 cooling systems by accessing the free e
00:00:25.790 00:00:25.800 lessons available at Learning dot dan
00:00:28.490 00:00:28.500 Foss comm
00:00:31.240 00:00:31.250 let's start with a very simple approach
00:00:33.160 00:00:33.170 to understanding the functioning of an
00:00:34.840 00:00:34.850 air conditioner
00:00:37.110 00:00:37.120 an air conditioner has two connected
00:00:39.299 00:00:39.309 coils with continuously flowing
00:00:41.250 00:00:41.260 refrigerant fluid inside them the coil
00:00:43.920 00:00:43.930 inside the room is called the evaporator
00:00:46.200 00:00:46.210 and the coil outside the room is called
00:00:48.420 00:00:48.430 the condenser the fundamental principle
00:00:51.420 00:00:51.430 of an air-conditioner is simple just
00:00:53.670 00:00:53.680 keep the evaporator cold
00:00:55.290 00:00:55.300 more specifically colder than the room
00:00:57.270 00:00:57.280 temperature and the condenser hot more
00:01:00.389 00:01:00.399 specifically hotter than the
00:01:01.920 00:01:01.930 surroundings with these conditions the
00:01:04.799 00:01:04.809 continuously flowing fluid will
00:01:06.780 00:01:06.790 obviously absorb the heat from the room
00:01:08.850 00:01:08.860 and eject it out to the surroundings
00:01:10.969 00:01:10.979 this is the fundamental rule of an
00:01:13.590 00:01:13.600 air-conditioner let's see how this rule
00:01:15.930 00:01:15.940 is implemented in practice
00:01:19.730 00:01:19.740 to achieve this objective two more
00:01:22.130 00:01:22.140 components are needed inside your
00:01:23.690 00:01:23.700 air-conditioner a compressor and an
00:01:26.660 00:01:26.670 expansion valve
00:01:28.940 00:01:28.950 as you can probably guess the compressor
00:01:31.459 00:01:31.469 increases the pressure of the
00:01:33.020 00:01:33.030 refrigerant here you can see a working
00:01:35.480 00:01:35.490 example of a reciprocating type
00:01:37.370 00:01:37.380 compressor the compressor handles the
00:01:40.279 00:01:40.289 refrigerant in its gaseous state so that
00:01:42.830 00:01:42.840 as it compresses the gas the temperature
00:01:44.870 00:01:44.880 rises along with the pressure the
00:01:48.020 00:01:48.030 temperature at the compressor outlet
00:01:49.969 00:01:49.979 will be far higher than the atmospheric
00:01:52.279 00:01:52.289 temperature therefore if you pass this
00:01:55.100 00:01:55.110 hot gas through the condenser heat
00:01:57.050 00:01:57.060 exchanger you can easily eject the heat
00:02:00.770 00:02:00.780 a fan in the condenser unit makes this
00:02:02.870 00:02:02.880 task easier
00:02:05.210 00:02:05.220 during this heat ejection phase the gas
00:02:07.970 00:02:07.980 gets condensed to a liquid
00:02:10.870 00:02:10.880 an expansion valve is fitted at the exit
00:02:13.540 00:02:13.550 of the condenser the purpose of the
00:02:15.850 00:02:15.860 expansion valve is to restrict the
00:02:17.980 00:02:17.990 refrigerant flow thus reducing the
00:02:20.230 00:02:20.240 pressure of the fluid
00:02:22.290 00:02:22.300 here comes the main trick you might be
00:02:25.260 00:02:25.270 aware that it is possible to boil a
00:02:27.300 00:02:27.310 liquid just by reducing the pressure
00:02:29.250 00:02:29.260 around it this phenomenon happens inside
00:02:32.520 00:02:32.530 the expansion valve as well as the
00:02:35.070 00:02:35.080 pressure drops one part of the
00:02:37.020 00:02:37.030 refrigerant liquid is evaporated however
00:02:39.660 00:02:39.670 for this evaporation to happen some
00:02:42.150 00:02:42.160 energy should be supplied to it this
00:02:44.670 00:02:44.680 energy comes from within the refrigerant
00:02:46.800 00:02:46.810 so it's temperature drops this is how
00:02:50.310 00:02:50.320 the cold refrigerant is produced inside
00:02:52.380 00:02:52.390 an air-conditioner this low temperature
00:02:54.900 00:02:54.910 refrigerant should be at a temperature
00:02:56.760 00:02:56.770 lower than the room temperature so
00:02:59.670 00:02:59.680 bypassing the rooms air over the
00:03:01.680 00:03:01.690 evaporator coil the room temperature
00:03:03.780 00:03:03.790 will drop the refrigerant gets converted
00:03:06.570 00:03:06.580 to vapor during this heat absorption
00:03:08.430 00:03:08.440 process
00:03:10.300 00:03:10.310 you might have heard a term called ton
00:03:12.460 00:03:12.470 associated with the air conditioners the
00:03:14.830 00:03:14.840 ton represents how much heat the
00:03:16.780 00:03:16.790 evaporator can absorb from the room in
00:03:18.760 00:03:18.770 simple words it represents an air
00:03:21.160 00:03:21.170 conditioners heat removal capability
00:03:24.680 00:03:24.690 in this way we have achieved the
00:03:26.870 00:03:26.880 fundamental rule of an air-conditioner
00:03:28.790 00:03:28.800 the temperature is lower than the room
00:03:30.950 00:03:30.960 temperature in the coil inside the room
00:03:33.020 00:03:33.030 and the temperature is more than the
00:03:35.330 00:03:35.340 atmospheric temperature in the coil
00:03:37.130 00:03:37.140 outside the room in an actual air
00:03:40.160 00:03:40.170 conditioner the compressor sits near to
00:03:42.470 00:03:42.480 the condenser and the expansion valve
00:03:44.330 00:03:44.340 sits near to the evaporator there are
00:03:47.570 00:03:47.580 some practical issues with this design
00:03:49.930 00:03:49.940 near to the evaporator coils the air
00:03:52.850 00:03:52.860 temperature will be quite low this will
00:03:55.070 00:03:55.080 lead to water condensation on the
00:03:56.990 00:03:57.000 evaporator coils that's why we need a
00:03:59.540 00:03:59.550 pipe to remove this water condensate
00:04:05.600 00:04:05.610 modern air conditioners use scroll
00:04:07.940 00:04:07.950 compressors instead of the reciprocating
00:04:10.100 00:04:10.110 type you can see how the compression
00:04:12.560 00:04:12.570 process happens from this animation they
00:04:15.680 00:04:15.690 are silent and they have good speed
00:04:17.600 00:04:17.610 control
00:04:22.060 00:04:22.070 do you know how your air conditioner is
00:04:24.430 00:04:24.440 able to maintain an almost steady room
00:04:26.770 00:04:26.780 temperature irrespective of the load
00:04:30.519 00:04:30.529 air conditioners use a variable speed
00:04:32.289 00:04:32.299 motor technology called inverter
00:04:34.809 00:04:34.819 technology for better temperature
00:04:36.849 00:04:36.859 control just by adjusting the motor
00:04:39.129 00:04:39.139 speed the compressor speed the
00:04:40.989 00:04:40.999 refrigerant flow rate and the cooling
00:04:42.729 00:04:42.739 capacity can be controlled accurately
00:04:47.189 00:04:47.199 here comes an interesting design
00:04:48.989 00:04:48.999 challenge for the air conditioner the
00:04:51.019 00:04:51.029 compressor of an air conditioner is
00:04:53.010 00:04:53.020 designed to handle only vapor and the
00:04:55.800 00:04:55.810 small fraction of liquid content can
00:04:57.689 00:04:57.699 affect its performance and damage the
00:04:59.850 00:04:59.860 compressor for these reasons it is
00:05:02.429 00:05:02.439 desired that the evaporator convert all
00:05:04.739 00:05:04.749 of the liquid to vapor and even increase
00:05:07.499 00:05:07.509 the temperature of the vapor by 5 to 8
00:05:09.719 00:05:09.729 degrees Celsius after the conversion how
00:05:13.200 00:05:13.210 does it make sure that the fluid which
00:05:14.909 00:05:14.919 enters the compressor is purely vapor
00:05:19.040 00:05:19.050 this condition is maintained by a
00:05:20.990 00:05:21.000 special kind of expansion valve called a
00:05:23.839 00:05:23.849 thermostatic expansion valve the
00:05:26.240 00:05:26.250 abbreviation is TX v the TX v is similar
00:05:30.080 00:05:30.090 to the expansion valve we saw earlier
00:05:32.059 00:05:32.069 but here the temperature of a bulb
00:05:34.760 00:05:34.770 controls the needle the bulb is
00:05:37.460 00:05:37.470 connected to the evaporator exit the
00:05:39.770 00:05:39.780 refrigerant inside the bulb is separated
00:05:42.499 00:05:42.509 from the main refrigeration cycle by a
00:05:44.719 00:05:44.729 diaphragm when the bulb is hot the
00:05:47.390 00:05:47.400 refrigerant inside it will be evaporated
00:05:49.670 00:05:49.680 and the needle will move down we know
00:05:51.860 00:05:51.870 the sudden cooling of the refrigerant is
00:05:53.689 00:05:53.699 achieved across the expansion valve with
00:05:56.240 00:05:56.250 the help of the restriction the narrower
00:05:58.909 00:05:58.919 the restriction the cooler the outlet
00:06:01.129 00:06:01.139 refrigerant will be
00:06:06.480 00:06:06.490 let's consider a bad situation for the
00:06:08.850 00:06:08.860 compressor assume the evaporator
00:06:11.370 00:06:11.380 temperature is not so low so the
00:06:13.469 00:06:13.479 evaporator absorbs very low heat and all
00:06:16.320 00:06:16.330 the liquid in it will not be converted
00:06:18.089 00:06:18.099 to vapor
00:06:18.980 00:06:18.990 thus the refrigerant which leaves for
00:06:21.809 00:06:21.819 the compressor will not be superheated
00:06:24.059 00:06:24.069 this low temperature at the evaporator
00:06:26.700 00:06:26.710 exit will immediately be sensed by the
00:06:28.860 00:06:28.870 ball
00:06:30.510 00:06:30.520 and will cause the needle to move
00:06:32.219 00:06:32.229 upwards and make the restriction
00:06:34.200 00:06:34.210 narrower the narrow restriction causes a
00:06:37.469 00:06:37.479 good temperature drop
00:06:38.850 00:06:38.860 thus the evaporator will receive much
00:06:41.339 00:06:41.349 cooler fluid and it can absorb a great
00:06:43.830 00:06:43.840 amount of heat this will make sure that
00:06:46.469 00:06:46.479 all the liquid will be converted to
00:06:48.360 00:06:48.370 vapor
00:06:51.800 00:06:51.810 the complex task of having a vapor only
00:06:54.290 00:06:54.300 condition at the compressor in that is
00:06:55.990 00:06:56.000 automatically maintained by the TXV
00:06:59.140 00:06:59.150 let us clear up a common misconception
00:07:01.370 00:07:01.380 at this stage T xv's do not control the
00:07:05.360 00:07:05.370 room temperature they just make sure
00:07:07.610 00:07:07.620 that the compressor receives the
00:07:09.140 00:07:09.150 refrigerant in pure vapor form the
00:07:11.780 00:07:11.790 refrigerant flow rate and the room
00:07:13.520 00:07:13.530 temperature are controlled by the speed
00:07:15.710 00:07:15.720 of the compressor
00:07:17.420 00:07:17.430 due to their simplicity and efficiency
00:07:19.990 00:07:20.000 TXV s are widely used in the industrial
00:07:23.030 00:07:23.040 and domestic applications to learn more
00:07:25.700 00:07:25.710 about t --xv s and hundreds of other
00:07:27.800 00:07:27.810 cooling topics please check out danfoss
00:07:30.409 00:07:30.419 learning a free training and
00:07:32.240 00:07:32.250 certification hub brought to you by
00:07:34.219 00:07:34.229 Danfoss visit learning Danfoss comm or
00:07:38.570 00:07:38.580 click the link in the video description
00:07:40.480 00:07:40.490 thank you

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