00:00:01.370 [Music] 00:00:04.05900:00:04.069 hey there guys Paul here from the 00:00:06.17000:00:06.180 engineering mindset calm in this video 00:00:08.41900:00:08.429 we're going to be looking at the 00:00:09.65000:00:09.660 evaporator of a chiller just want to add 00:00:13.37000:00:13.380 if you have not already looked at the 00:00:15.20000:00:15.210 other videos we've made on the series of 00:00:17.09000:00:17.100 chillers I highly recommend you go back 00:00:18.85900:00:18.869 and start watching these just to build 00:00:20.75000:00:20.760 up that base knowledge of the chilled 00:00:22.67000:00:22.680 water system and the chillers to 00:00:24.41000:00:24.420 understand fully how they work before 00:00:26.42000:00:26.430 moving on to this section anyway so the 00:00:30.29000:00:30.300 evaporator the evaporator is this 00:00:32.26900:00:32.279 cylinder here and it's located just 00:00:34.69000:00:34.700 after the expansion valve and just 00:00:37.54900:00:37.559 before the suction line which goes into 00:00:39.35000:00:39.360 the compressor by now you should also 00:00:42.38000:00:42.390 know that the evaporator collects all 00:00:45.20000:00:45.210 the unwanted heat within the building 00:00:46.94000:00:46.950 and this is where all the chilled water 00:00:49.97000:00:49.980 is produced so it sends off that chilled 00:00:52.36900:00:52.379 water around the building this goes into 00:00:54.11000:00:54.120 the a hate shus collects all that 00:00:56.11900:00:56.129 unwanted heat from the building's from 00:00:58.49000:00:58.500 the building and the floors that then 00:01:00.13900:01:00.149 gets sent back to the evaporator that 00:01:02.18000:01:02.190 where that heat is given up and sent by 00:01:04.96900:01:04.979 the refrigerant over through the 00:01:07.01000:01:07.020 compressor into the condenser one thing 00:01:11.27000:01:11.280 you're going to notice about the 00:01:12.26000:01:12.270 evaporator is this this black foam 00:01:14.81000:01:14.820 that's covered all over the evaporator 00:01:16.55000:01:16.560 and the connections to and around it 00:01:19.71900:01:19.729 this is the insulation and this is 00:01:22.76000:01:22.770 really important to have this on the 00:01:24.67900:01:24.689 evaporator and that's because all the 00:01:26.63000:01:26.640 chilled water that cold water is 00:01:28.88000:01:28.890 produced here in the evaporator and that 00:01:32.24000:01:32.250 chilled water is actually really 00:01:33.80000:01:33.810 expensive to produce and what you want 00:01:36.83000:01:36.840 is to ensure that all the chilled water 00:01:38.69000:01:38.700 that is produced in here all the money 00:01:40.78900:01:40.799 you spend on this machine producing this 00:01:43.24900:01:43.259 chilled water all that water gets sent 00:01:46.28000:01:46.290 out around the building to collect all 00:01:48.46900:01:48.479 the unwanted heat and bring that back so 00:01:51.23000:01:51.240 that the other evaporator can pick up 00:01:53.92900:01:53.939 that heat and get rid of it if you don't 00:01:58.55000:01:58.560 have insulation on the evaporator then 00:02:01.13000:02:01.140 you're going to pick up unwanted heat 00:02:02.69000:02:02.700 within this plant room coming for the 00:02:05.03000:02:05.040 machines the motion for that you don't 00:02:06.80000:02:06.810 want any of that you can use fresh air 00:02:08.33000:02:08.340 to get rid of rid of this you know 00:02:09.80000:02:09.810 certain circumstances movie card but you 00:02:12.53000:02:12.540 don't want to pick up 00:02:13.76000:02:13.770 the additional heat on the way so you 00:02:15.44000:02:15.450 want to make sure that all the chilled 00:02:17.78000:02:17.790 water pipe work is insulated and also 00:02:20.15000:02:20.160 that the evaporator is also heavily 00:02:22.43000:02:22.440 insulated as well if your chiller does 00:02:25.67000:02:25.680 not have the evaporator insulated I 00:02:27.47000:02:27.480 highly recommend you bring this up with 00:02:29.81000:02:29.820 your your manager whoever and get this 00:02:32.48000:02:32.490 as a project to have that insulated now 00:02:36.62000:02:36.630 typically like I said there's this kind 00:02:38.72000:02:38.730 of foam type insulation that covering 00:02:41.03000:02:41.040 the evaporator in the shell when it 00:02:42.74000:02:42.750 connections around there that's going to 00:02:44.90000:02:44.910 be you know a vinyl nitrate polymer type 00:02:47.39000:02:47.400 insulation and it'll be around 19 00:02:50.69000:02:50.700 millimeters thick you know 3/4 of means 00:02:52.85000:02:52.860 something like this if you speak to your 00:02:56.72000:02:56.730 the manufacturer of your chiller they'll 00:02:58.46000:02:58.470 almost certainly be able to provide you 00:03:00.74000:03:00.750 with a pre-made pre-cut set to cover all 00:03:03.89000:03:03.900 of this and it should with all your new 00:03:05.63000:03:05.640 chillers it should come with standard 00:03:08.14000:03:08.150 now the evaporator is made up of this 00:03:11.27000:03:11.280 this shell here that sits obviously 00:03:14.75000:03:14.760 around the outside and there are also 00:03:17.42000:03:17.430 these tubes which sit inside the shell 00:03:20.48000:03:20.490 and they run the length of the 00:03:22.36000:03:22.370 evaporator from one end to another now 00:03:26.96000:03:26.970 looking at the tubes which run inside 00:03:29.30000:03:29.310 the shell it's important to remember 00:03:31.13000:03:31.140 that the the water there sits on the 00:03:35.18000:03:35.190 inside of the tubes just like that up 00:03:39.26000:03:39.270 there but the refrigerant sits on the 00:03:43.31000:03:43.320 outside of the tubes the the to the 00:03:46.31000:03:46.320 refrigerant of the water never mix 00:03:47.93000:03:47.940 they're always separated by the wall of 00:03:50.54000:03:50.550 this tube that runs along they're 00:03:54.41000:03:54.420 completely isolated from one another so 00:03:58.24000:03:58.250 what's happening here is you've got the 00:04:00.71000:04:00.720 tube sitting there running along the 00:04:02.39000:04:02.400 length of the evaporator like I said the 00:04:06.59000:04:06.600 water sits on the inside and the 00:04:08.09000:04:08.100 refrigerant which I've you know just 00:04:09.50000:04:09.510 giving it to this green murky color here 00:04:12.64000:04:12.650 that's it's on along the outside and 00:04:16.72000:04:16.730 then all the heat that's within the 00:04:19.37000:04:19.380 water is given up to the refrigerant so 00:04:22.03900:04:22.049 it just transfers that heat through the 00:04:23.87000:04:23.880 pipe wall through the tube wall and out 00:04:26.09000:04:26.100 into the refrigerator 00:04:27.64000:04:27.650 and the the refrigerant picks up that 00:04:32.39000:04:32.400 heat and it boils it comes in as a 00:04:34.13000:04:34.140 liquid with the bottom of the chiller 00:04:36.26000:04:36.270 for the bottom of the evaporator picks 00:04:39.74000:04:39.750 up that heat and it boils off you know 00:04:41.48000:04:41.490 and it evaporates and heads off towards 00:04:43.94000:04:43.950 the suction line and into the compressor 00:04:48.31000:04:48.320 so we know that the refrigerant enters 00:04:50.74000:04:50.750 through the bottom of the evaporator as 00:04:54.14000:04:54.150 a liquid it boils off because of the 00:04:57.80000:04:57.810 temperature of the water in here and the 00:04:59.54000:04:59.550 low evaporation temperature or boiling 00:05:02.57000:05:02.580 point of the refrigerant and all that 00:05:05.15000:05:05.160 refrigerant as it's a gas form gaseous 00:05:08.84000:05:08.850 form that leaves through the suction 00:05:11.03000:05:11.040 lining into the compressor the chilled 00:05:15.02000:05:15.030 water however comes in a you know around 00:05:17.93000:05:17.940 6 12 degrees Celsius flows through the 00:05:21.41000:05:21.420 evaporator and then leaves at the other 00:05:23.90000:05:23.910 end or back through the same end but 00:05:26.12000:05:26.130 we'll look at that in more detail 00:05:27.47000:05:27.480 shortly 00:05:28.04000:05:28.050 at around 12 degrees Celsius now to keep 00:05:32.60000:05:32.610 the refrigerant inside the shell and 00:05:34.55000:05:34.560 make sure it's you know held in there 00:05:36.74000:05:36.750 doesn't leak we're going to need to seal 00:05:38.81000:05:38.820 the evaporator shell so at each end of 00:05:43.19000:05:43.200 the evaporator we fit these metal plates 00:05:47.03000:05:47.040 and that's welded to the shell to ensure 00:05:49.82000:05:49.830 is completely sealed in there the plate 00:05:54.47000:05:54.480 is obviously drilled to allow these 00:05:55.94000:05:55.950 tubes to be fitted on the through them 00:05:59.00000:05:59.010 to run along the length of them but 00:06:01.22000:06:01.230 these are usually not welded the tubes 00:06:03.59000:06:03.600 are not welded to the the metal plate 00:06:07.73000:06:07.740 here but what happens is they'll fit at 00:06:12.47000:06:12.480 all inside here the tubes will be 00:06:14.03000:06:14.040 inserted fairly loosely the tool will 00:06:17.09000:06:17.100 fit inside the pipe work and then this 00:06:21.88000:06:21.890 expands the pipe diameter and creates a 00:06:25.43000:06:25.440 perfect seal between the tube which is 00:06:28.67000:06:28.680 usually our copper material and the 00:06:31.24000:06:31.250 carbon steel end plate 00:06:36.57000:06:36.580 I'll just show you what real evaporator 00:06:39.02900:06:39.039 looks like so you can see what the tubes 00:06:40.92000:06:40.930 here you've got this the area inside 00:06:43.86000:06:43.870 where there is no no tubes and though 00:06:45.51000:06:45.520 piercings through this wall and that is 00:06:47.73000:06:47.740 to allow for the refrigerant vapor to 00:06:50.15900:06:50.169 build up there and collect before going 00:06:52.29000:06:52.300 off into the suction line by the way 00:06:56.33900:06:56.349 these plugs which you can see here and 00:06:58.52900:06:58.539 these are just been they've been put 00:07:01.17000:07:01.180 here just because the tubes have 00:07:02.70000:07:02.710 actually burst so they need to be sealed 00:07:05.27900:07:05.289 off so that the machine can continue to 00:07:07.52900:07:07.539 operate to be you should put these plugs 00:07:09.54000:07:09.550 in you got to shut the Machine down 00:07:11.37000:07:11.380 obviously and you put these in and that 00:07:13.62000:07:13.630 just seals off the tube to allow 00:07:15.02900:07:15.039 machines go back to working without 00:07:16.95000:07:16.960 replacing the tubes and doing some quite 00:07:19.64900:07:19.659 expensive additional work just looking 00:07:23.12900:07:23.139 at a bit of a close-up of the evaporator 00:07:25.35000:07:25.360 and how the tubes are actually sealed 00:07:27.12000:07:27.130 here so you can see that the tubes are 00:07:29.21900:07:29.229 not welded to this steel plate and 00:07:30.89900:07:30.909 what's happened is they've been expanded 00:07:33.20000:07:33.210 really the metal wall here as being 00:07:36.37900:07:36.389 compressed or crushed against this metal 00:07:40.02000:07:40.030 so tightly that it forms almost perfect 00:07:42.71900:07:42.729 seal and then the end caps are then 00:07:44.58000:07:44.590 pushed the rounded over to obviously 00:07:46.77000:07:46.780 seal the end there and stop that from 00:07:48.33000:07:48.340 moving back and forward now to keep the 00:07:53.76000:07:53.770 water inside the evaporator and it's 00:07:56.70000:07:56.710 channel around we use these things here 00:07:58.76900:07:58.779 which are placed on either end of the 00:08:00.80900:08:00.819 evaporator and these are known as water 00:08:02.82000:08:02.830 boxes now there's some slightly 00:08:05.45900:08:05.469 different versions of water boxes this 00:08:08.64000:08:08.650 one has got op C two openings so this 00:08:10.49900:08:10.509 would allow chilled water to enter and 00:08:13.55900:08:13.569 then leave and there's this metal plate 00:08:15.93000:08:15.940 in between the two which is known as a 00:08:17.87900:08:17.889 baffle and this separates the flow of 00:08:20.90900:08:20.919 the two either entering and leaving 00:08:23.14900:08:23.159 chilled water to ensure there's no 00:08:25.35000:08:25.360 mixing of the water temperature and keep 00:08:28.40900:08:28.419 them separated and that's much like you 00:08:32.37000:08:32.380 can see here we've got an inlet the 00:08:35.21900:08:35.229 water flows in and then it flows out and 00:08:37.38000:08:37.390 exits through this secondary 00:08:40.57900:08:40.589 alternatively you may have a plate like 00:08:43.58900:08:43.599 this which does not have the baffle in 00:08:46.07900:08:46.089 between and so this just simply channels 00:08:49.19900:08:49.209 the water and the water 00:08:50.82000:08:50.830 Hiep out of one answer it will hit this 00:08:53.58000:08:53.590 turn 180 degrees and then flow back into 00:08:56.39000:08:56.400 some more tubes and I'll explain what I 00:09:00.57000:09:00.580 mean by that 00:09:01.55000:09:01.560 so evaporators are often referred to as 00:09:04.62000:09:04.630 the number of passes which they have 00:09:07.85000:09:07.860 what does this mean well in from the 00:09:11.52000:09:11.530 evaporator is said to have had one pass 00:09:14.07000:09:14.080 that means that the chilled water simply 00:09:16.74000:09:16.750 enters one side flows all the way 00:09:19.23000:09:19.240 through the tubes and into the water box 00:09:21.78000:09:21.790 in the other end and then leaves at the 00:09:24.12000:09:24.130 other end much like you can see with 00:09:26.91000:09:26.920 this chiller there is only one pipe 00:09:28.71000:09:28.720 quite a large one and it is entering one 00:09:31.20000:09:31.210 end and then leaving the other there's a 00:09:34.68000:09:34.690 one pass evaporator alternatively you 00:09:39.09000:09:39.100 could have a to pass evaporator and 00:09:40.62000:09:40.630 that's where the chilled water enters it 00:09:43.02000:09:43.030 into this water box the baffle stops it 00:09:45.96000:09:45.970 spreading to the other half the water 00:09:47.67000:09:47.680 then passes through the tubes into the 00:09:49.56000:09:49.570 end baffle which does not at the end 00:09:52.41000:09:52.420 water box which does not have a baffle 00:09:54.18000:09:54.190 so the water just carries on and flows 00:09:55.83000:09:55.840 through it continues out to the other 00:09:57.87000:09:57.880 side of the original water box and that 00:10:00.54000:10:00.550 then leaves to go around the building 00:10:03.38000:10:03.390 that's what's happening on this chilly 00:10:06.09000:10:06.100 here you can see the evaporator 00:10:07.38000:10:07.390 there is no pipes leaving the end there 00:10:09.87000:10:09.880 but there are two pipes on this end 00:10:11.58000:10:11.590 which means it is a two pass evaporator 00:10:14.40000:10:14.410 and the final one is a free pass 00:10:17.88000:10:17.890 evaporator and that is where the chilled 00:10:20.82000:10:20.830 water enters into the water box here the 00:10:23.70000:10:23.710 baffle prevents it traveling all the way 00:10:25.29000:10:25.300 through gets channeled through these 00:10:27.60000:10:27.610 tubes into the water box at the other 00:10:29.43000:10:29.440 end with another baffle that channels it 00:10:31.83000:10:31.840 through these tubes into this water box 00:10:33.69000:10:33.700 the original one there's no air flight 00:10:36.03000:10:36.040 to go there's no exit so it is channeled 00:10:37.92000:10:37.930 once again off back to the final of the 00:10:40.83000:10:40.840 secondary water box and the baffle there 00:10:43.58000:10:43.590 channels that out it's important to 00:10:45.93000:10:45.940 remember if you are looking at a 00:10:49.07000:10:49.080 evaporator and you're not sure if it is 00:10:50.97000:10:50.980 a one or a free pass system 00:10:52.95000:10:52.960 well the pipes will not be aligned so 00:10:55.29000:10:55.300 you can see that it's not a straight 00:10:56.85000:10:56.860 pass through so it indicates that it is 00:10:59.94000:10:59.950 a free pass but as always don't really 00:11:03.78000:11:03.790 make assumptions on things check with 00:11:05.70000:11:05.710 the manufacturers there should be a 00:11:07.74000:11:07.750 serial number stamped onto the chilla 00:11:10.05000:11:10.060 you can have a look at this on the 00:11:11.34000:11:11.350 manufacturers website to find out how 00:11:14.10000:11:14.110 that evaporator works and the dimensions 00:11:16.20000:11:16.210 etc you can see the plate here the 00:11:20.39000:11:20.400 manufacturers stamp will be on there the 00:11:22.35000:11:22.360 name and also the model number just have 00:11:24.63000:11:24.640 a look at this alternatively 00:11:26.01000:11:26.020 alternatively there should be some 00:11:27.66000:11:27.670 documents stored on site to tell you all 00:11:30.75000:11:30.760 the manufactures literature for all the 00:11:33.15000:11:33.160 machines which are there have a look 00:11:34.35000:11:34.360 there also now just on the materials of 00:11:37.50000:11:37.510 the chiller of the evaporator the shell 00:11:40.20000:11:40.210 and the water boxes and the end plate 00:11:43.08000:11:43.090 they'll all usually be made from carbon 00:11:46.47000:11:46.480 steel and they'll be built to a certain 00:11:49.53000:11:49.540 standard depending on which country 00:11:50.64000:11:50.650 you're in so we've hold a certain amount 00:11:53.85000:11:53.860 of pressure now these are built they 00:11:56.49000:11:56.500 generally get a giant sheet of carbon 00:11:59.88000:11:59.890 steel and they roll this around into a 00:12:03.21000:12:03.220 sphere into a pipe shape and then they 00:12:06.03000:12:06.040 weld along the seam the tubes in the 00:12:09.51000:12:09.520 other hand are generally made from a 00:12:11.22000:12:11.230 copper copper copper alloy sometimes 00:12:15.30000:12:15.310 they're made from maybe like stainless 00:12:16.77000:12:16.780 steel and that all depends on what the 00:12:19.59000:12:19.600 you know the water is on the other side 00:12:21.84000:12:21.850 and is it going to really corrode et 00:12:23.31000:12:23.320 cetera so certain materials for certain 00:12:27.20000:12:27.210 applications and it really depends on 00:12:30.18000:12:30.190 the application for which chiller you 00:12:32.43000:12:32.440 can use I highly recommend you speak to 00:12:35.22000:12:35.230 any manufacturer before you install this 00:12:37.11000:12:37.120 and also to obviously through your 00:12:39.39000:12:39.400 specialists now some of you may have 00:12:43.11000:12:43.120 noticed these things on the side of the 00:12:44.82000:12:44.830 evaporator 00:12:45.42000:12:45.430 these are sight glasses so these allow 00:12:48.60000:12:48.610 you there's a better glass here and 00:12:49.83000:12:49.840 these allow the user to look inside the 00:12:52.20000:12:52.210 evaporator and you can see the 00:12:53.94000:12:53.950 refrigerant as well as the tubes let's 00:12:56.58000:12:56.590 have a look inside now looking inside 00:12:59.40000:12:59.410 the sight glass you can see the tubes 00:13:00.99000:13:01.000 here running along the length of the 00:13:02.52000:13:02.530 evaporator and you'll notice that these 00:13:04.68000:13:04.690 tubes are not smooth they've got these 00:13:06.81000:13:06.820 weird ridges will wear along them and 00:13:09.15000:13:09.160 now there's a really important reason 00:13:10.71000:13:10.720 for them and that is that these fins 00:13:13.68000:13:13.690 increase the surface area 00:13:16.34000:13:16.350 of the tube that means that more heat 00:13:19.64000:13:19.650 can transfer out of the evaporite illed 00:13:23.03000:13:23.040 water and into the refrigerant this 00:13:26.45000:13:26.460 means that the chiller is more efficient 00:13:28.97000:13:28.980 it means the evaporator and the chiller 00:13:32.78000:13:32.790 in general is much smaller so the price 00:13:34.70000:13:34.710 would go down and also the fact that 00:13:37.22000:13:37.230 space in the building is at a premium so 00:13:39.55000:13:39.560 the less space you can take up through 00:13:42.83000:13:42.840 HVAC equipment and electrical equipment 00:13:44.89000:13:44.900 the more space in the building you can 00:13:48.32000:13:48.330 use to rent out to other companies or 00:13:50.87000:13:50.880 you can fit and process equipment etc I 00:13:54.46000:13:54.470 quickly show you how efficient the the 00:13:59.21000:13:59.220 fins are when they're placed on the 00:14:00.80000:14:00.810 tubes so if we imagine this is the 00:14:02.69000:14:02.700 chilled water passing through and this 00:14:04.82000:14:04.830 is the the wall here the of the tubes 00:14:08.80000:14:08.810 now the surface area is just the length 00:14:12.80000:14:12.810 along here and that's where the heat 00:14:15.14000:14:15.150 will transfer out into the refrigerant 00:14:19.60000:14:19.610 now we've no fins the heat transfer like 00:14:22.61000:14:22.620 I said is just going to occur there but 00:14:25.79000:14:25.800 if we place fins along the length of 00:14:28.61000:14:28.620 this tube then the surface area 00:14:31.25000:14:31.260 increases dramatically and this allows 00:14:35.03000:14:35.040 much greater heat dissipation and heat 00:14:38.30000:14:38.310 transfer out of the chilled water and 00:14:40.79000:14:40.800 into the refrigerant you may have also 00:14:44.21000:14:44.220 noticed these pipes coming out the top 00:14:47.66000:14:47.670 here look a bit like this one here these 00:14:50.03000:14:50.040 are just relief valves so these valves 00:14:53.09000:14:53.100 which are here they are spring-loaded 00:14:54.41000:14:54.420 and if the pressure increased too high 00:14:57.05000:14:57.060 within the evaporator from the 00:14:59.48000:14:59.490 refrigerant these spring-loaded valves 00:15:02.21000:15:02.220 would open and allow the gas to vent out 00:15:04.49000:15:04.500 and get passed through these pipes out 00:15:06.32000:15:06.330 and unfortunately vent into the 00:15:08.12000:15:08.130 atmosphere and and then once the 00:15:11.12000:15:11.130 pressures dropped back to an acceptable 00:15:12.83000:15:12.840 level the springs inside will just 00:15:14.75000:15:14.760 automatically close and continue to seal 00:15:17.42000:15:17.430 that in okay everyone that's the end of 00:15:20.18000:15:20.190 this video thank you very much for 00:15:21.56000:15:21.570 watching if this has helped you then 00:15:23.42000:15:23.430 please like and share the video and 00:15:25.55000:15:25.560 don't forget to subscribe you can also 00:15:28.01000:15:28.020 follow us on Facebook Twitter 00:15:30.13900:15:30.149 check out the website etc if you have 00:15:33.49900:15:33.509 any questions please leave them in the 00:15:35.03000:15:35.040 comment section below and don't forget 00:15:37.75900:15:37.769 to check out our own videos thanks very 00:15:39.76900:15:39.779 much
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