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Micro Plate Heat Exchanger (MPHE) - How they work, working principle hvac phx
WEBVTT Kind: captions Language: en
00:00:04.320 --> 00:00:05.153 Hey there, guys. 00:00:05.153 --> 00:00:06.830 Paul here from TheEngineeringMindset.com. 00:00:06.830 --> 00:00:08.350 In this video, we're going to be learning 00:00:08.350 --> 00:00:12.460 all about Micro Plate heat exchangers, or MPHEs for short. 00:00:12.460 --> 00:00:14.880 These are the most advanced heat exchangers to date, 00:00:14.880 --> 00:00:18.130 and they enable heat to be transferred more efficiently 00:00:18.130 --> 00:00:20.600 than any previous model of heat exchanger. 00:00:20.600 --> 00:00:22.640 So we're going to be looking at how they work, 00:00:22.640 --> 00:00:24.630 where they are used, why they are used, 00:00:24.630 --> 00:00:26.800 and the benefits of using these. 00:00:26.800 --> 00:00:29.220 Before we jump in, though, I just want to thank Danfoss 00:00:29.220 --> 00:00:30.440 for sponsoring this video. 00:00:30.440 --> 00:00:32.660 They have some excellent Micro Plate heat exchanger 00:00:32.660 --> 00:00:35.460 solutions that fit a wide variety of applications, 00:00:35.460 --> 00:00:37.990 including their new Z-design series. 00:00:37.990 --> 00:00:39.760 Not only is a Z-design compatible 00:00:39.760 --> 00:00:41.020 with numerous refrigerants, 00:00:41.020 --> 00:00:44.290 it also enables a 40% higher heat transfer rate 00:00:44.290 --> 00:00:46.640 and decreases energy consumption. 00:00:46.640 --> 00:00:48.140 If you are interested in learning more 00:00:48.140 --> 00:00:50.490 about what the Z-design 00:00:50.490 --> 00:00:52.160 can do for your cooling system, 00:00:52.160 --> 00:00:53.780 be sure to check out their website 00:00:53.780 --> 00:00:56.300 using the link in the video description below. 00:00:56.300 --> 00:00:58.920 Let's just recap on the purpose of heat exchangers 00:00:58.920 --> 00:01:00.010 and how they work. 00:01:00.010 --> 00:01:02.490 The purpose of heat exchangers in general terms 00:01:02.490 --> 00:01:04.480 is to allow thermal energy to transfer 00:01:04.480 --> 00:01:06.930 between two fluids without the fluids 00:01:06.930 --> 00:01:09.720 coming into direct contact with each other. 00:01:09.720 --> 00:01:11.820 The fluids can be anything, oil, water, 00:01:11.820 --> 00:01:14.680 refrigerant, milk, steam, etcetera. 00:01:14.680 --> 00:01:17.440 Although, for this video, we are primarily focusing 00:01:17.440 --> 00:01:20.760 on Micro Plate heat exchangers and their application 00:01:20.760 --> 00:01:23.460 within heating and cooling systems for buildings, 00:01:23.460 --> 00:01:26.020 which use water and refrigerants. 00:01:26.020 --> 00:01:28.160 These are plate heat exchangers which can be used 00:01:28.160 --> 00:01:30.410 for the evaporator and the condenser, 00:01:30.410 --> 00:01:32.880 for example, within chillers and heat pumps. 00:01:32.880 --> 00:01:34.400 When used for an evaporator, 00:01:34.400 --> 00:01:36.410 the vapor liquid mixture enters 00:01:36.410 --> 00:01:38.100 the bottom of the heat exchanger 00:01:38.100 --> 00:01:39.140 where the thermal energy 00:01:39.140 --> 00:01:41.320 is transferred into the refrigerant, 00:01:41.320 --> 00:01:43.660 which causes it to boil and evaporate. 00:01:43.660 --> 00:01:46.120 This then leaves through the top of the heat exchanger 00:01:46.120 --> 00:01:48.600 with some degree of superheat. 00:01:48.600 --> 00:01:51.200 When used as a condenser, the hot refrigerant gas 00:01:51.200 --> 00:01:53.060 enters the top of the heat exchanger 00:01:53.060 --> 00:01:55.450 where it begins to transfer its thermal energy 00:01:55.450 --> 00:01:58.610 out of the refrigerant and into the secondary fluid 00:01:58.610 --> 00:02:01.620 which cools the refrigerant down and causes it to condense 00:02:01.620 --> 00:02:03.993 into a partly sub-cooled liquid state. 00:02:05.160 --> 00:02:07.810 Traditionally, shell and tube heat exchangers were used, 00:02:07.810 --> 00:02:09.710 and they still are for certain applications. 00:02:09.710 --> 00:02:11.150 But then along came the invention 00:02:11.150 --> 00:02:12.880 of the plate heat exchanger 00:02:12.880 --> 00:02:16.100 which was a much more compact and efficient heat exchanger. 00:02:16.100 --> 00:02:19.790 These can come in either gasket or brazed plate variations. 00:02:19.790 --> 00:02:22.330 Plate heat exchangers use thin sheets of metal, 00:02:22.330 --> 00:02:24.320 known as plates, to separate the fluids 00:02:24.320 --> 00:02:27.070 and create separate channels for the fluids to flow through 00:02:27.070 --> 00:02:29.310 and exchange their thermal energy. 00:02:29.310 --> 00:02:31.400 For this thermal transfer to take place, 00:02:31.400 --> 00:02:34.110 two fluids are used, a primary and a secondary, 00:02:34.110 --> 00:02:36.950 which both enter and exit through different ports. 00:02:36.950 --> 00:02:39.220 The fluids must be at different temperatures. 00:02:39.220 --> 00:02:40.790 The greater the temperature difference, 00:02:40.790 --> 00:02:43.530 then the higher the heat transfer rate will be. 00:02:43.530 --> 00:02:45.510 The two fluids will never meet or mix. 00:02:45.510 --> 00:02:48.290 They are always separated by the plates of metal, 00:02:48.290 --> 00:02:50.570 and the thermal energy flows between them, 00:02:50.570 --> 00:02:53.170 passing through the plate's material. 00:02:53.170 --> 00:02:54.720 As I mentioned, there are two types 00:02:54.720 --> 00:02:58.200 of plate heat exchangers, gasket and brazed plate. 00:02:58.200 --> 00:03:00.800 Gasket plate heat exchangers use a rubber gasket 00:03:00.800 --> 00:03:03.050 to separate the plates and form a seal 00:03:03.050 --> 00:03:05.530 which directs the fluids into certain channels 00:03:05.530 --> 00:03:06.890 as well as preventing the fluids 00:03:06.890 --> 00:03:08.220 from entering other channels. 00:03:08.220 --> 00:03:09.580 This prevents the fluids from coming 00:03:09.580 --> 00:03:11.910 into direct contact with each other. 00:03:11.910 --> 00:03:14.640 This type of heat exchanger can be dismantled for cleaning, 00:03:14.640 --> 00:03:17.100 and additional plates can even be added or removed 00:03:17.100 --> 00:03:21.020 to increase or decrease the heat transfer capacity rating. 00:03:21.020 --> 00:03:24.070 Brazed plate heat exchangers also use thin plates 00:03:24.070 --> 00:03:26.470 to create the channels for the fluids to pass through. 00:03:26.470 --> 00:03:28.880 However, they do not use gaskets. 00:03:28.880 --> 00:03:32.160 They are instead braze welded, typically using copper. 00:03:32.160 --> 00:03:33.660 During the brazing process, 00:03:33.660 --> 00:03:36.900 all the surfaces which physically touch another surface 00:03:36.900 --> 00:03:39.340 will form a weld along that connecting edge. 00:03:39.340 --> 00:03:43.070 So by orientating the plates, permanent seals are created 00:03:43.070 --> 00:03:45.030 which direct the flow of the fluids 00:03:45.030 --> 00:03:47.830 and prevent them from coming into direct contact. 00:03:47.830 --> 00:03:50.030 Brazed plate heat exchangers can't, therefore, 00:03:50.030 --> 00:03:51.480 be dismantled for cleaning, 00:03:51.480 --> 00:03:54.030 and no plates can be added or removed. 00:03:54.030 --> 00:03:57.080 However, brazed plates can still be flush cleaned. 00:03:57.080 --> 00:03:58.620 And because they do not use gaskets, 00:03:58.620 --> 00:04:00.380 they are very unlikely to leak, 00:04:00.380 --> 00:04:02.770 whereas, with gasket plate heat exchangers, 00:04:02.770 --> 00:04:05.230 these are going to have a higher possibility. 00:04:05.230 --> 00:04:08.850 Although, with good maintenance, no leaks should occur. 00:04:08.850 --> 00:04:10.610 Traditionally, plate heat exchangers 00:04:10.610 --> 00:04:12.240 would use grooved plates which have 00:04:12.240 --> 00:04:14.250 these V or chevron shape patterns 00:04:14.250 --> 00:04:16.800 pressed into them of different variations. 00:04:16.800 --> 00:04:19.350 Then along came the Micro Plate heat exchanger 00:04:19.350 --> 00:04:22.040 which is the next evolution of plate heat exchangers 00:04:22.040 --> 00:04:24.350 and the latest in heat exchanger technology, 00:04:24.350 --> 00:04:25.380 and they have been designed 00:04:25.380 --> 00:04:29.120 with energy efficiency and sustainability in focus. 00:04:29.120 --> 00:04:31.140 Rather than using the traditional method, 00:04:31.140 --> 00:04:32.800 or grooved or chevron plates, 00:04:32.800 --> 00:04:36.000 Micro Plate heat exchangers use small dimples. 00:04:36.000 --> 00:04:38.410 There are a number of reasons why this is a great design, 00:04:38.410 --> 00:04:40.730 firstly, because the dimples spread the fluids 00:04:40.730 --> 00:04:44.610 across the surface of the heat exchanger much more evenly. 00:04:44.610 --> 00:04:47.900 This maximizes the heat transfer surface area 00:04:47.900 --> 00:04:49.460 which means that there is more time 00:04:49.460 --> 00:04:53.700 for the heat transfer over across between the two fluids. 00:04:53.700 --> 00:04:55.530 The dimples also cause the fluids 00:04:55.530 --> 00:04:57.470 to move much more turbulently 00:04:57.470 --> 00:04:59.160 because their dimples cause the fluids 00:04:59.160 --> 00:05:01.220 to change direction much more 00:05:01.220 --> 00:05:03.840 compared to a typical chevron pattern. 00:05:03.840 --> 00:05:06.230 The reason turbulence is good for heat exchangers 00:05:06.230 --> 00:05:08.270 is because when fluids flow smoothly, 00:05:08.270 --> 00:05:10.100 which is known as a laminar flow, 00:05:10.100 --> 00:05:12.070 the fluids actually flow in layers, 00:05:12.070 --> 00:05:14.200 and the outermost layer moves the slowest, 00:05:14.200 --> 00:05:16.950 and the centermost layer moves the fastest. 00:05:16.950 --> 00:05:20.370 Heat is then transferred only into the outermost layer. 00:05:20.370 --> 00:05:22.810 The fluid in the center can pass straight through 00:05:22.810 --> 00:05:25.160 and will carry little to no heat away. 00:05:25.160 --> 00:05:27.230 This means you pay to pump a fluid 00:05:27.230 --> 00:05:28.690 through the heat exchanger, 00:05:28.690 --> 00:05:32.020 but the fluid wasn't able to pick up much or any heat. 00:05:32.020 --> 00:05:34.650 So you therefore need to pump the fluid through again 00:05:34.650 --> 00:05:37.710 to try and capture all the heat that it missed. 00:05:37.710 --> 00:05:39.900 Turbulent flow causes these layers to mix, 00:05:39.900 --> 00:05:42.410 and that forces the heat into the center of the flow 00:05:42.410 --> 00:05:43.670 so it can be carried away, 00:05:43.670 --> 00:05:45.960 allowing for more heat to transfer over. 00:05:45.960 --> 00:05:49.630 So the efficiency of the heat exchanger is greatly improved. 00:05:49.630 --> 00:05:51.950 The size, spacing, and shape of the dimples 00:05:51.950 --> 00:05:54.330 plays a critical part in the efficiency, 00:05:54.330 --> 00:05:56.130 so these are specifically designed 00:05:56.130 --> 00:05:57.640 for the application required 00:05:57.640 --> 00:06:00.870 as well as the heat transfer rate and the pressure loss. 00:06:00.870 --> 00:06:03.640 For example, there are specifically designed heat exchangers 00:06:03.640 --> 00:06:05.440 for the evaporator and the condenser 00:06:05.440 --> 00:06:06.940 of heat pumps and chillers. 00:06:06.940 --> 00:06:09.260 There's also more general-purpose heat exchangers, 00:06:09.260 --> 00:06:12.090 like waste heat recovery, perhaps from a data center 00:06:12.090 --> 00:06:13.970 to a district heating system. 00:06:13.970 --> 00:06:15.700 So depending on the application, 00:06:15.700 --> 00:06:18.250 you can get them in anything from three kilowatts 00:06:18.250 --> 00:06:20.420 up to and over 400 kilowatts. 00:06:20.420 --> 00:06:22.280 And depending again on the application, 00:06:22.280 --> 00:06:25.030 they can be either brazed plate or gasket. 00:06:25.030 --> 00:06:27.680 The heat exchangers also use counter flow design. 00:06:27.680 --> 00:06:29.650 And this means that the two fluids will flow 00:06:29.650 --> 00:06:31.630 in the opposite direction to each other, 00:06:31.630 --> 00:06:33.870 and this increases the heat transfer rate 00:06:33.870 --> 00:06:36.770 and the log mean temperature difference, or the LMTD, 00:06:36.770 --> 00:06:39.890 which results in less heat transfer area being required, 00:06:39.890 --> 00:06:43.340 meaning that the heat exchangers can be made smaller. 00:06:43.340 --> 00:06:44.930 Like any plate heat exchanger, 00:06:44.930 --> 00:06:47.100 the purpose of Micro Plate heat exchangers 00:06:47.100 --> 00:06:50.350 is to transfer heat from one fluid over to another, 00:06:50.350 --> 00:06:52.880 not to the ambient air and its surroundings. 00:06:52.880 --> 00:06:54.160 A lot of people forget this 00:06:54.160 --> 00:06:56.060 and do not insulate their heat exchangers 00:06:56.060 --> 00:06:57.520 which just wastes energy. 00:06:57.520 --> 00:06:59.070 For example, if you're using these 00:06:59.070 --> 00:07:00.660 for a cooling application, 00:07:00.660 --> 00:07:03.060 then it costs money to generate the chilled water. 00:07:03.060 --> 00:07:05.410 And if you don't insulate your heat exchangers, 00:07:05.410 --> 00:07:07.110 then it's just going to pick up waste heat 00:07:07.110 --> 00:07:09.060 before it's even reached its destination 00:07:09.060 --> 00:07:10.790 to provide air conditioning. 00:07:10.790 --> 00:07:12.730 Therefore, if you see a plate heat exchanger 00:07:12.730 --> 00:07:15.560 that is exposed, or its surfaces are visible, 00:07:15.560 --> 00:07:16.850 then get it insulated. 00:07:16.850 --> 00:07:18.000 Check with the manufacturer. 00:07:18.000 --> 00:07:20.540 They should be able to provide an insulation panel 00:07:20.540 --> 00:07:23.560 with the exact measurements for the heat exchanger you have, 00:07:23.560 --> 00:07:25.530 and these can quickly and easily be removed 00:07:25.530 --> 00:07:27.430 should you need to perform maintenance. 00:07:27.430 --> 00:07:29.340 This will also increase the efficiency 00:07:29.340 --> 00:07:30.563 of the heat exchanger. 00:07:31.780 --> 00:07:34.600 Some of the benefits of using 00:07:34.600 --> 00:07:36.860 are that it has reduced refrigerant volume. 00:07:36.860 --> 00:07:38.270 The heat exchanges are smaller, 00:07:38.270 --> 00:07:40.540 so your system needs less refrigerant. 00:07:40.540 --> 00:07:42.330 Improved flow means that the pressure loss 00:07:42.330 --> 00:07:45.260 is kept to a minimum, so the process requires less energy 00:07:45.260 --> 00:07:47.250 to pump water around the system. 00:07:47.250 --> 00:07:49.710 The heat exchanger has a higher mechanical strength. 00:07:49.710 --> 00:07:52.330 It provides a stable evaporation process, 00:07:52.330 --> 00:07:54.370 has a longer system life span. 00:07:54.370 --> 00:07:56.210 It's quick and easy to install. 00:07:56.210 --> 00:07:59.600 It's smaller, lightweight, uses less raw materials, 00:07:59.600 --> 00:08:01.510 and has less of an environmental impact. 00:08:01.510 --> 00:08:03.490 It also has a higher heat transfer rate, 00:08:03.490 --> 00:08:07.990 up to 40% compared to traditional fishbone design. 00:08:07.990 --> 00:08:09.100 All right, thanks for watching, guys. 00:08:09.100 --> 00:08:10.730 Before we wrap up, I just want to give 00:08:10.730 --> 00:08:12.250 one more quick shout out to Danfoss 00:08:12.250 --> 00:08:13.340 00:08:13.340 --> 00:08:14.260 Don't forget to check out 00:08:14.260 --> 00:08:16.500 the new Z-design Micro 00:08:16.500 --> 00:08:19.440 by following the link in the video description below. 00:08:19.440 --> 00:08:20.770 Okay, that's it for this video. 00:08:20.770 --> 00:08:21.950 Thank you very much for watching. 00:08:21.950 --> 00:08:23.790 I hope this has helped you and you've enjoyed it. 00:08:23.790 --> 00:08:25.020 If so, then please don't forget 00:08:25.020 --> 00:08:26.560 to like, subscribe, and share, 00:08:26.560 --> 00:08:28.770 and check us out on Facebook, Twitter, Google+, 00:08:28.770 --> 00:08:31.200 and of course TheEngineeringMindset.com. 00:08:31.200 --> 00:08:33.867 Once again, thanks for watching.
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