00:00:01.510 [Music] 00:00:04.48000:00:04.490 hey thanks for watching this quick video 00:00:06.74000:00:06.750 is on the evaporator and the evaporator 00:00:09.77000:00:09.780 is probably I don't want to say it's the 00:00:12.08000:00:12.090 most important component because every 00:00:13.70000:00:13.710 component is critical to the operation 00:00:15.65000:00:15.660 of the basic refrigerant circuit but it 00:00:17.48000:00:17.490 is the component that does the thing 00:00:19.58000:00:19.590 that we most relate to with air 00:00:21.92000:00:21.930 conditioning and refrigeration which is 00:00:23.35900:00:23.369 it is the part that absorbs heat we 00:00:25.75900:00:25.769 would often think that the evaporator is 00:00:27.14000:00:27.150 the part that makes cold but as often is 00:00:29.92900:00:29.939 a you know beat to death in the HVAC 00:00:32.20900:00:32.219 industry you can't make cold cold is the 00:00:35.38900:00:35.399 absence of heat or a differential 00:00:37.88000:00:37.890 between something that is hotter and 00:00:39.83000:00:39.840 something that is colder it's an it's an 00:00:41.75000:00:41.760 explanatory word that we use we call 00:00:43.61000:00:43.620 something cold 00:00:44.42000:00:44.430 we're just saying it's cold in 00:00:46.04000:00:46.050 relationship to the temperature of our 00:00:47.95900:00:47.969 skin or the temperature that we would 00:00:50.15000:00:50.160 like it to be outdoors or whatever the 00:00:51.68000:00:51.690 case may be but the evaporator for all 00:00:53.66000:00:53.670 intents and purposes as far as we're 00:00:55.25000:00:55.260 concerned is cold if you touch most of 00:00:57.17000:00:57.180 Aperta calls they feel cold on air 00:00:59.72000:00:59.730 conditioners the evaporator coils under 00:01:01.27900:01:01.289 normal sort of rated conditions are 00:01:03.41000:01:03.420 about 40 degrees Fahrenheit and of 00:01:05.14900:01:05.159 course that does vary depending on load 00:01:07.42900:01:07.439 conditions and in freezers you can get 00:01:09.67900:01:09.689 evaporator coils all the way down to 00:01:10.96900:01:10.979 minus you know 30 minus 40 degrees 00:01:12.80000:01:12.810 depending on the situation so we have 00:01:15.05000:01:15.060 evaporator coils that are a wide range 00:01:16.91000:01:16.920 of temperatures but they are all almost 00:01:20.45000:01:20.460 all as far as we're concerned cold but 00:01:23.63000:01:23.640 when something is cold that means it's a 00:01:25.24900:01:25.259 lower temperature than something else so 00:01:28.28000:01:28.290 that way heat moves into it which is why 00:01:30.59000:01:30.600 in my basic refrigeration description I 00:01:33.05000:01:33.060 talked about the evaporator as being the 00:01:34.73000:01:34.740 heat absorber it pulls in heat and 00:01:37.55000:01:37.560 that's really what we're trying to do 00:01:38.78000:01:38.790 when we're attempting to cool something 00:01:40.39900:01:40.409 because we make the evaporator coil of a 00:01:42.31900:01:42.329 lower temperature than either the room 00:01:44.09000:01:44.100 of the box the air going over it so that 00:01:46.39900:01:46.409 way heat goes out of that room or that 00:01:48.49900:01:48.509 refrigerator box or that freezer and the 00:01:50.71900:01:50.729 heat is attracted into that of Africa 00:01:52.52000:01:52.530 coil and often for most of the typical 00:01:54.17000:01:54.180 basic systems we're working on we're 00:01:55.67000:01:55.680 just flowing air over the evaporator 00:01:57.64900:01:57.659 coil over those fins on that evaporator 00:01:59.81000:01:59.820 coil and then as it passes across that 00:02:02.30000:02:02.310 metal and the refrigerant moves through 00:02:03.92000:02:03.930 it's absorbing heat through the metal 00:02:05.92900:02:05.939 into the refrigerant the fins on those 00:02:07.99900:02:08.009 coils that you'll often see act as 00:02:10.24000:02:10.250 additional surface area to help 00:02:12.77000:02:12.780 give it a little bit more contact time 00:02:14.18000:02:14.190 so that as that airs passing over it has 00:02:16.55000:02:16.560 more contact time on the metal so that 00:02:18.41000:02:18.420 way that refrigerant inside that 00:02:20.09000:02:20.100 evaporator coil can absorb heat and we 00:02:22.19000:02:22.200 like we talked about before the reason 00:02:23.39000:02:23.400 why the evaporator coil is cooler than 00:02:26.18000:02:26.190 lower temperature than the other 00:02:28.19000:02:28.200 components is because there's a pressure 00:02:29.87000:02:29.880 drop right before it we're going to talk 00:02:31.30900:02:31.319 about the metering device separately but 00:02:32.93000:02:32.940 the metering device provides a pressure 00:02:34.25000:02:34.260 drop going into the evaporator coil and 00:02:36.44000:02:36.450 so that evaporator coil can be a lower 00:02:38.36000:02:38.370 temperature the reason why we call it an 00:02:39.94900:02:39.959 evaporator coil is because the 00:02:41.87000:02:41.880 refrigerant inside boils or evaporates 00:02:44.44900:02:44.459 and those two words don't mean exactly 00:02:45.62000:02:45.630 the same thing I would rather that it 00:02:47.87000:02:47.880 was called the boil Raider instead of 00:02:49.46000:02:49.470 the evaporator but if you remember it as 00:02:51.65000:02:51.660 a boiler ater that might help you 00:02:53.27000:02:53.280 remember what it does because what's 00:02:54.83000:02:54.840 going on inside there is the rapid 00:02:56.47900:02:56.489 change from liquid to vapor State so 00:02:59.12000:02:59.130 it's a it's this change from liquid to 00:03:00.74000:03:00.750 vapor right when it comes out of that 00:03:02.36000:03:02.370 metering device it already has flashed 00:03:04.22000:03:04.230 off some of that refrigerant from liquid 00:03:06.17000:03:06.180 to vapor a lot of time a lot of books 00:03:08.15000:03:08.160 will say you know approximately 70 to 30 00:03:09.83000:03:09.840 percent so 70 percent would be liquid 30 00:03:11.84000:03:11.850 percent would be vapor when it enters 00:03:13.28000:03:13.290 that evaporator coil but that varies 00:03:14.78000:03:14.790 quite a bit and there's a lot of 00:03:15.83000:03:15.840 conditions that impact that but right as 00:03:17.47900:03:17.489 Ann enters the evaporator coil its are 00:03:19.10000:03:19.110 automatically changing state and it's 00:03:20.72000:03:20.730 boiling if you imagine what water looks 00:03:22.55000:03:22.560 like when it boils in a pot that's very 00:03:24.47000:03:24.480 similar to what its gonna look like as 00:03:25.85000:03:25.860 its flowing through the lines it's gonna 00:03:27.59000:03:27.600 be that changing state there's gonna be 00:03:29.24000:03:29.250 you know bubbles forming in it as it's 00:03:31.03900:03:31.049 boiling going through that evaporator 00:03:32.50900:03:32.519 coil now that's sort of blows our minds 00:03:34.19000:03:34.200 because we imagine that's things that 00:03:35.69000:03:35.700 are boiling are hot and the only reason 00:03:37.31000:03:37.320 we imagine that is because the only 00:03:38.56900:03:38.579 thing we observe boiling in our 00:03:40.03900:03:40.049 day-to-day lives is water and water does 00:03:42.02000:03:42.030 boil at a high temperature compared to 00:03:44.69000:03:44.700 our skin at atmospheric pressure 212 00:03:47.81000:03:47.820 degrees Fahrenheit or a hundred degrees 00:03:49.18000:03:49.190 Celsius is what water boils out at 00:03:51.77000:03:51.780 atmospheric pressure whereas most the 00:03:53.24000:03:53.250 refrigerants we work with they boil at 00:03:54.71000:03:54.720 very low temperatures at atmospheric 00:03:56.39000:03:56.400 pressure in fact we have to kind of 00:03:58.13000:03:58.140 pressurize them above atmospheric 00:03:59.47900:03:59.489 pressure in order to manipulate them to 00:04:01.61000:04:01.620 boil at the temperatures that we want so 00:04:03.80000:04:03.810 am i manipulating the pressure we can 00:04:05.06000:04:05.070 manipulate the temperature of that 00:04:06.71000:04:06.720 evaporator coil you imagine this boiling 00:04:08.66000:04:08.670 refrigerant moving through it we can 00:04:09.80000:04:09.810 manipulate the temperature at which it's 00:04:12.05000:04:12.060 changing State by manipulating the 00:04:13.75900:04:13.769 pressure like we talked about before 00:04:14.87000:04:14.880 higher pressure equals higher 00:04:16.72900:04:16.739 temperature lower pressure equals lower 00:04:18.86000:04:18.870 temperature and that's also true when 00:04:20.77900:04:20.789 you're dealing with what we would call a 00:04:21.92000:04:21.930 saturated refrigerant that means that 00:04:24.14000:04:24.150 it's part liquid in part vapor together 00:04:26.00000:04:26.010 at this 00:04:26.42000:04:26.430 place at the same time otherwise known 00:04:28.37000:04:28.380 as boiling or condensing inside the 00:04:30.29000:04:30.300 evaporator coil it's boiling it's 00:04:31.76000:04:31.770 changing state from liquid to vapor 00:04:33.49900:04:33.509 like I said fairly rapidly as it 00:04:35.12000:04:35.130 circulates through the system now just 00:04:36.77000:04:36.780 like sort of the opposite of the 00:04:38.33000:04:38.340 condenser where we talked about how the 00:04:39.95000:04:39.960 refrigerant goes in the top and then as 00:04:41.48000:04:41.490 it becomes a liquid and kind of settles 00:04:43.04000:04:43.050 down it goes down to the bottom on an 00:04:45.02000:04:45.030 evaporator coil we're generally gonna 00:04:46.31000:04:46.320 feed it into the bottom and then as it 00:04:47.99000:04:48.000 boils off to a vapor it's gonna come out 00:04:50.02900:04:50.039 the top so generally you'll notice that 00:04:52.04000:04:52.050 if Africa cools are fed with that 00:04:53.96000:04:53.970 boiling liquid refrigerant in the bottom 00:04:55.73000:04:55.740 and then the refrigerant comes out the 00:04:57.29000:04:57.300 top and then feeds down the suction line 00:04:59.57000:04:59.580 it's very important in air conditioning 00:05:01.15900:05:01.169 that we control that temperature of the 00:05:02.96000:05:02.970 evaporator coil and keep it above the 00:05:04.93900:05:04.949 freezing temperature because most air 00:05:06.56000:05:06.570 conditioners don't have any way of 00:05:07.99900:05:08.009 defrosting so we've got to keep that 00:05:09.77000:05:09.780 coil surface temperature above 32 00:05:11.87000:05:11.880 degrees to ensure that we don't start to 00:05:14.51000:05:14.520 build up frost and ice now in 00:05:16.21900:05:16.229 practicality you can actually get it a 00:05:17.87000:05:17.880 little below 32 and not have Frost 00:05:19.70000:05:19.710 because there's a slight difference 00:05:20.71900:05:20.729 between the temperature of the 00:05:22.40000:05:22.410 refrigerant inside the coil and the 00:05:24.20000:05:24.210 actual surface temperature of the metal 00:05:26.15000:05:26.160 on the coil there's just like variance 00:05:27.89000:05:27.900 there and then also if you have to have 00:05:30.08000:05:30.090 sufficient moisture and sufficient dwell 00:05:31.85000:05:31.860 time and order for it to start to freeze 00:05:33.35000:05:33.360 so that's why in a lot of arid 00:05:35.08900:05:35.099 environments people won't get the same 00:05:37.52000:05:37.530 types of frost patterns that we get down 00:05:39.50000:05:39.510 in Florida where we have very high 00:05:40.79000:05:40.800 relative humidity and so there's 00:05:42.71000:05:42.720 different air flows that are needed in 00:05:44.18000:05:44.190 different circumstances but regardless 00:05:45.89000:05:45.900 we generally want to keep that 00:05:47.27000:05:47.280 evaporator coil above 32 degrees 00:05:49.87900:05:49.889 Fahrenheit so that we do not build up 00:05:52.10000:05:52.110 frost on that coil juxtapose that to say 00:05:54.32000:05:54.330 a freezer where we obviously have to get 00:05:56.08900:05:56.099 that evaporator coil below 32 degrees 00:05:57.92000:05:57.930 temperature otherwise we would not get 00:06:00.11000:06:00.120 the product below 32 it wouldn't be a 00:06:01.85000:06:01.860 freezer unless it was below 32 in fact a 00:06:04.33900:06:04.349 lot of freezers are minus 10 minus 20 00:06:06.35000:06:06.360 degrees Fahrenheit and so you have to 00:06:07.93900:06:07.949 have an evaporator coil that is lower 00:06:09.89000:06:09.900 than the temperature of that desired 00:06:12.43900:06:12.449 temperature of the box or of the product 00:06:14.14900:06:14.159 inside the box so if you open up the 00:06:16.04000:06:16.050 freezer at home and let's say that it's 00:06:17.81000:06:17.820 minus 10 degrees inside that freezer you 00:06:20.02900:06:20.039 have to have an evaporator coil that is 00:06:21.62000:06:21.630 at least -9 degrees otherwise heat isn't 00:06:24.74000:06:24.750 gonna move out of that box into that of 00:06:27.14000:06:27.150 Aperta quele 00:06:27.86000:06:27.870 like we said the evaporator coil is the 00:06:29.18000:06:29.190 heat absorber and it must be lower 00:06:30.71000:06:30.720 temperature than the air that's passing 00:06:32.33000:06:32.340 over it or than the space that it's in 00:06:34.15900:06:34.169 in the case of in the case of a freezer 00:06:35.89900:06:35.909 or a refrigerator in practice you're 00:06:37.87900:06:37.889 actually gonna see more like a 10 00:06:39.67000:06:39.680 to 20 degree lower temperature of a 00:06:42.48000:06:42.490 participation x' again very much depends 00:06:45.40000:06:45.410 on the particular equipment in order to 00:06:47.08000:06:47.090 absorb heat out of that space 00:06:48.85000:06:48.860 effectively so what we're doing with an 00:06:51.12900:06:51.139 evaporator coil what we really care 00:06:52.51000:06:52.520 about is we care about making sure that 00:06:54.27900:06:54.289 we control the temperature to the 00:06:56.02000:06:56.030 temperature that we want that of a 00:06:57.27900:06:57.289 protocol to be and we also have to 00:06:59.26000:06:59.270 ensure that we flow refrigerant let 00:07:01.33000:07:01.340 boiling liquid refrigerant through most 00:07:03.18900:07:03.199 of the coil now the last part of the 00:07:05.37900:07:05.389 coil is what we call the super heating 00:07:06.99900:07:07.009 phase if you remember what we talked 00:07:08.14000:07:08.150 about the condenser you have D super 00:07:09.99900:07:10.009 heating then you have condensing the 00:07:11.86000:07:11.870 change of state from vapor to liquid and 00:07:14.20000:07:14.210 then you have sub cooling and an 00:07:15.70000:07:15.710 evaporator coil you have the boiling 00:07:18.07000:07:18.080 phase or the flash gas or whatever you 00:07:20.08000:07:20.090 want to call it the the point at which 00:07:21.31000:07:21.320 it's changing state its saturated state 00:07:23.83000:07:23.840 it's boiling and then at the end you 00:07:25.62900:07:25.639 have the super heating phase super 00:07:27.40000:07:27.410 heating can only happen when it is fully 00:07:29.08000:07:29.090 vapor and as that refrigerant finally 00:07:30.87900:07:30.889 makes its way all the way through that 00:07:32.11000:07:32.120 coil at the end it's going to be fully 00:07:34.33000:07:34.340 vapor and that's when we when you get 00:07:36.04000:07:36.050 further on and you learn what superheat 00:07:37.62900:07:37.639 is that's all superheat is it's just 00:07:39.31000:07:39.320 using temperature and pressure in order 00:07:41.35000:07:41.360 to tell us how far through that 00:07:43.33000:07:43.340 evaporator coil that liquid refrigerant 00:07:45.33900:07:45.349 is boiling so how long through that 00:07:47.62000:07:47.630 evaporator coil is that there's still 00:07:48.67000:07:48.680 some liquid it's gonna start off at say 00:07:50.29000:07:50.300 70 percent liquid refrigerant and then 00:07:52.68900:07:52.699 it's gonna go to a 60 50 40 30 10 and 00:07:55.21000:07:55.220 then finally we'll go to zero percent 00:07:57.07000:07:57.080 liquid refrigerant and that's when we 00:07:58.62900:07:58.639 can start to superheat that's when that 00:08:00.12900:08:00.139 temperature can start to rise so we're 00:08:01.83900:08:01.849 gonna control the temperature of that 00:08:04.14900:08:04.159 boiling through that evaporator coil 00:08:05.62000:08:05.630 through pressure and then we're also 00:08:07.62900:08:07.639 going to control how far through the 00:08:09.31000:08:09.320 coil we're feeding the refrigerant now 00:08:11.26000:08:11.270 everything in the air conditioning 00:08:13.02900:08:13.039 refrigeration system affects everything 00:08:14.62000:08:14.630 else so the amount of refrigerant how 00:08:17.08000:08:17.090 well the compressor is moving that 00:08:18.76000:08:18.770 refrigerant how well it's circulating it 00:08:20.37900:08:20.389 if it's compressing properly whether or 00:08:22.08900:08:22.099 not your condenser coil is dirty or has 00:08:23.95000:08:23.960 problems or whether or not the airflow 00:08:25.42000:08:25.430 moving over that of a protocol is too 00:08:27.01000:08:27.020 low there's all kinds of factors that 00:08:29.77000:08:29.780 impact count of a protocol absorbs heat 00:08:32.14000:08:32.150 but remember that when we're attempting 00:08:33.43000:08:33.440 to cool something that really is the 00:08:34.81000:08:34.820 point so it's very important that we get 00:08:36.31000:08:36.320 all the situations correct so that way 00:08:38.76900:08:38.779 we have a proper evaporator temperature 00:08:40.51000:08:40.520 and so that way we're feeding that 00:08:42.43000:08:42.440 boiling liquid refrigerant through the 00:08:44.17000:08:44.180 bulk of that coil till we hit what we 00:08:46.39000:08:46.400 call our target superheat the point at 00:08:48.01000:08:48.020 which it's it's designed to become a 00:08:50.53000:08:50.540 vapor before it goes back to that 00:08:52.15000:08:52.160 compressor again 00:08:52.87000:08:52.880 because that compressor is a vapor pump 00:08:55.18000:08:55.190 what's the point here the point is is 00:08:56.89000:08:56.900 that we have to control that temperature 00:08:58.96000:08:58.970 how far it feeds through one thing about 00:09:01.42000:09:01.430 the evaporator coil itself is that we 00:09:03.07000:09:03.080 are moving the right medium across it 00:09:05.98000:09:05.990 medium can be air or water or whatever 00:09:07.51000:09:07.520 it is that were cooling and that we're 00:09:08.92000:09:08.930 moving it across in the correct rates so 00:09:10.69000:09:10.700 for example the really common example of 00:09:12.97000:09:12.980 this would be having a dirty air filter 00:09:14.38000:09:14.390 if you have a dirty air filter then 00:09:16.48000:09:16.490 there's not enough air moving over that 00:09:18.25000:09:18.260 of a protocol that evaporator coils job 00:09:20.17000:09:20.180 is to remove heat from the air and if 00:09:22.81000:09:22.820 there's not enough air then there's not 00:09:24.34000:09:24.350 enough heat and the pressure in that 00:09:26.17000:09:26.180 evaporator coil will begin to drop and 00:09:27.85000:09:27.860 that's why you will find often that air 00:09:30.28000:09:30.290 conditioners that freeze up or even 00:09:32.20000:09:32.210 coolers or freezers that are freezing up 00:09:34.15000:09:34.160 too much many times that's due to low 00:09:36.52000:09:36.530 air flow so we have to control that 00:09:38.65000:09:38.660 airflow moving over that coil if it was 00:09:40.57000:09:40.580 a chiller where it was cooling water 00:09:42.34000:09:42.350 then you'd have to control the amount of 00:09:43.75000:09:43.760 water that was moving across it because 00:09:45.61000:09:45.620 remember the evaporators job is to 00:09:47.83000:09:47.840 absorb heat so we have to give it the 00:09:49.81000:09:49.820 right amount of heat for it to absorb 00:09:51.64000:09:51.650 for it to function properly so that is 00:09:53.98000:09:53.990 just a very quick introduction I could 00:09:55.66000:09:55.670 sit here and talk for hours about 00:09:56.68000:09:56.690 evaporator coils but hopefully that gave 00:09:58.57000:09:58.580 you a sense of the evaporator coil the 00:10:00.58000:10:00.590 heat absorbing component of the basic 00:10:03.37000:10:03.380 refrigerant circuit will get you on the 00:10:05.08000:10:05.090 next video 00:10:05.59000:10:05.60000:10:18.12000:10:18.130 you
Office location
Engineering company LOTUS®
Russia, Ekaterinburg, Lunacharskogo street, 240/12