And the YouTube pulled here from the engineering Mindset calm in this video We're gonna be looking at the basic hvAC system, and this is an essential part of any building Because it supplies the heated ventilated and [air-conditioned] air To to the space and it ensures that it is the correct temperature the Correct humidity and also the correct Level of Co2 the correct freshness of air in that room to keep the occupants. Oh, maybe the equipment Maybe it's serving some offices. Maybe it's serving your home. Maybe it's serving a data center or even just a server room and So I'll see each one of these will have a different approach needs different conditions to be kept him and So the the characteristics will change but we're going to look at just a simple Scenario for how one of these would be set out? obviously if you're watching this you're probably just selling out in building services, so but you know it's important that we start off with the More simpler systems they can get far more complex than this, but this would be a great video just to get your Understanding your level of knowledge built up, so you can move on to those ones so one [of] the main focuses we're going to be looking at is this part here, which is the Ahu or the air handling unit. It's got a slightly different name around the world, but this is [in] an acronym which I work, too But we can be looking through how this works and each one of these components. What's happening inside, and how that air? enters into the building into the ahu is Conditioned what's happening? And we'll have a look at some real-life examples as well of each part of that Now if you remember from one of the first videos I did on this channel we looked at this kind of Schematic here of how each part of the Ahu Sorry of the hVAC system is connected and we looked at how the the chiller here down in the basement the ahu and The cooling Towers how they're all connected and and what they're doing there so We're going to be looking [at] this part here today. Which is the ahu that air handling unit, and that is what supplies the hVAC? system or Conditioned air to to the to the floor or the floors or the area within the building So we will focus on this part today, but just to recap your minds there if you haven't watched the video on this system Please go back or check out the channel and please go back and watch the one the first videos you put on there about how the chiller cooling Tower, Nhu's work together and we've also got some videos on the both the cooling Tower and also the chiller so you can get an understanding of that and And I was just going to say I'm pretty pleased that some of you was spotted that This pump here was actually piped around the wrong way So this pump should actually be connected to the riser here or the flow pipe [for] going up to the cooling tower of the condenser water system [I'm] fortunate. I made a mistake when I was rushing to put this video together and I piped it onto here, but thank you for pointing that correction out and just run you through this again, so Here we've got the evaporator on the bottom of the chiller And that's where the chilled or the cool cold water is Produced so that chilled water is then pumped up through the riser and then enters taps off of there enters the floor and then enters into the ahu and we're going to be looking at how that and that gives off It's cool there so that cool water called water chilled water will be entering into our coil inside there and And the water then returns through that into the riser there within this Space needs to [be] conditioned. So there's a fan inside there which [we'll] also be looking at and that's going to suck the air from the office into the ahu and that will then Cool it down and wait heat it and make humidify and it's also going to filter it and check that There's enough fresh air in that space as well And then that air is going to be pushed out onto the floors through the ductwork I haven't shown the ductwork on this book you'll see an example shortly, and that's distributed around the office so that that water there that that warm air which is returned enters into here gives up its heat, so it transfers the warm air the heat from [that] into the coil of Cold water and the cold water gives off. It's cool into the air so it comes out cold air here and that obviously raises the temperature of all of that water and That really returns it back to this riser into the evaporator of the chiller Where it then gives off its heat into the condenser side of the chiller that is then? Pumped up [there] two separate systems by the way you should know this from the other videos. I've done But that heat is [inter] up to the cooling towers where it was rejected? And that and the water then the condensed water drops a few degrees Celsius and then or Fahrenheit and then returns back into the condenser they're ready to pick up more heat from the building so we're going to go along and Look at how this system. Now works So let's just have a look at the model. We [built] here. It's just a very basic model of an office floor It can be much more complex than this obviously If you're watching this you're probably at the beginners level and you're wanting to learn and expand your knowledge in hVAC and building services [so] let's stick with a fair a simple example for now What's happening? Here is we've got an area within the building known as a plant room and Within there is where all the mechanical and electrical? assets are kept so this is where all the engineers will be and usually people who are in the offices in these areas here and Will never see this and they'll have no idea that This is actually in in their building and well their power and air conditioning ETc is all controlled from But this is probably the [area] where you will be spending most your time as you're watching this you're probably an engineer or facilities manager or in a similar sort of field, so Let's just have a quick look at what this is doing Now we've got some Sumi if you [imagine], this is the outside of the building so we've got two grills just on here and This is just a mess and all that's really doing is stopping any any material coming into the ahu and I'll just show you an example there of one of these grills catching a lot of rubbish, so this was intake was positioned near [the] bins of the building and If this mesh hadn't have been there Then this could have potentially [been] sucked into the fans It should have been picked up other filters on the other side which we'll look at in a bit but it still could [have] built up [an] inside and caused some damage in there, so It's good to have a grill on the outside first to catch anything stop any animals or anything getting in there? You know anything that could cause any damage and it's obviously important to clean this off periodically as well So coming back to the model, and [you'll] notice here that we've got the two ducts We've got the one on the bottom here and the one on the top so this one is acting as the supply and this one is acting as the return of the discharge here, so Here fresh air is coming in and entering into the ahu and this one will be all the dirty air well the warm Use there is being pushed out out here and then back into the atmosphere [and] it's obviously Important not to have these two [ducts] too close together Because you just get recirculation So the ideally these would not be positioned so close, but you know for example, and you can see how this is working I've left it so close in the real world. Do not do this. Yeah, don't put it as close [as] that so let's go [back] to the ahu Position [a] [bit] better, so the supply Air will enter into here It's being sucked in and there's a fan [in] here And we're going to look at all these components one by one don't worry we'll just go through and make sure you understand what the system is doing first, so once that air has been pulled into the ahu and it passes through here some which is the hVAC parts inside and that then gets pushed into the ductwork and That gets sent off around the building It looks it could also go into a riser here And that can go [out] that could spread to several floors it could go [down] below as well, we could These could potentially be Positioned on the roof and these could be supplying all the floors below this could be in the basement it could be Feeding all the floors above up to a certain height [or] it could be in this example way. You've got one ahu per floor Maybe these are all attended tentative offices so a different company rents out each floor and they want full control of all their their air conditioning [hVAc] so In this example, you know this is just a simple example where we've got two two main offices and a private one, maybe and This is per floor so that Conditioned Air is then entering and then it channels [up] [here] into this ductwork and comes out these grills Enters into the room it will come and is dispersed and diffuse into the room [these] will be carefully positioned and the designed to sir to make sure that there's adequate flow in the room, and that's capturing the right areas and That will carry on through all the rooms here until it's got a dead end or it could continue [two] more rooms? but it will cap off at one point and that conditioned air then enters into the space where it will be circulated around and that will then Control at wall. It will heat up or cool down the air inside I'm changing the humidity as well, and also if you imagine this is a room full of people [on] on computers. Maybe it's a cool center [there's] a lot of heat being generated in there, so you've got to get rid of that. You'll need to you need to supply Cold air or cooler air to it and we don't to be too cold because the staff are inside and if you imagine someone sitting underneath here, they they don't want Six degree Celsius air being dumped onto their heads they'll get sick and they'll be off work So it's got a you've got to maintain certain conditions which will be agreed on in the lease of the contract as well and And also the the level of fresh air in there as well, so there will be Sensors in this room measuring the amount of Co2 the temperature? ETC and And then over the back here. We've got another grill, and this is going to the return duct work see I've also labeled them here supply and return So all their air is going in pushing into this room circulating around conditioning it and then it's entering back [into] the return duct and that makes its way back into the return and side of the ahu and There is also a fan in this one. Which is sucking that air in and that's that's blowing that into the main chamber and And [then] often then we'll look at it later, but there's some dampers in here and that will control how much of that air Recirculates, and how much of [that] goes [back] it is rejected out of the vent here into the atmosphere So just to show you some examples of what a hate use might look like in the real world here's just a few examples of ones I've been working on [over] the years and You'll see here. This is a very small. I hate you It's only supplying One room they're kind of a medium sized room But it's got the same Setup as a larger system although this one is just recirculating the same air within the room and there's an extract elsewhere for supply for Fresh Air and But this one, it's just bringing in that return air It's coming in it's being filtered. We you can see you've got the pressure gauge here We'll look at this each part of this more later on as well Then we've got the heating coil here You can see you got the flow there and then this returning And then we continue. There's a panel access panel here and then it hits into the cooling coil that has the flow here and Return going along some pressure gauges there and then it continues through here So it's never fooled here. Actually we've got the pressure gauge going across there and then inside This part here would be a fan which is sucking all this air in and pushing it through and that then pushes that air up And back to the space the second ahu which is going to look at This is slightly different. It's only got a cooling coil on it So the airs coming in here and it's being sent off again off into the space But you'll notice that this one [has] got Some vFDs on its and vSTS variable speed drives or variable frequency drive and they control the speed of the induction motor which is connected to the fan and fans obviously pushing that so if you change the speed of the induction motor if you change the frequency that it's operating at from 50 or 60 Hertz down to 40 Hertz maybe then you'll slow the revolutions of the induction motor down, and that's directly connected [to] the to the fan or maybe not directly coupled it it might be on a belt drive, ETC, but You can change the flow the volume of flow volume of air into the space through these here You'll also see these isolators here, so you can cut the power off to Whatever, they're [feeling] so these two here will be directly feeding the fan as well other motor and the final example this one [this] has got the flow and return on top of each other and but you might notice that This has got two two heating coils on it and also that the air on this one actually comes in and transfers This is fresh coming in and supplied here And then the return is coming in and it crosses over down here out and in a way This is a much more complex version Which we'll look at in future videos right now you don't really need to understand that but I just thought I'd show you some examples of what [a] Hate use will look like in the real world now to open up the ahu You're going to need to open Some of the panels up the access panels which are purposely there for that exact reason so you can climb inside and have a local? Fix Or change the filters change the belt Etc So on the Edge use on the on the pounds you can access you'll see These handles here you might have [handle] so it might just be a panel key fitting in this instance here they've [got] the panel keys there to run do these and just lift those off and In this case you would just turn these and that one the hook and that will allow the entire panel to come off It's obviously important to switch off any fan. That's inside here first Cut the power because it's obviously very dangerous and you might get sucked in and potentially lose an arm or a finger or something, so Please make sure you was to do that and you can use a panel key like this just to gain access and open up and have a look inside the hu and While we're on that point, I'm just going to actually take the sides the panels off of this I hate you Just so you can look inside. I'll just show you But some little doors there, so you could? Look inside like a real one in this one. That's got the filters But we'll look in these and just to make it clearer and easier for everyone. I'm just going to take these panels off So [I've] [taken] the sides off of this. I hate you and now you can see what some [of] the components are inside and Remember we've [got] the supply side down the bottom here and the return side at the top here and from this you [can] see it's a it's a fairly typical example of opportunity you know the typical [office] supply and That is that we've got the supply coming in it's coming in through the grills then Past the Dampers. It's coming in it's got the panel filters here then the bag filters And then it's passing through these coils in this configuration. I've done it that heating is first and then cooling You may have it just heating you may have which is cooling. You may have Cooling before and you might have some humidifiers ETc in there But this is fairly typical at least for the uk most of Europe And then we've got the supply fan here. Which is been pushing that conditioned air off and into the ductwork to go around and feed the floors where it's it's brought back through this that work here being sucked by this fan again driven by this induction motor and That's pushing that air into here and then when it gets to here the controls of the BMS system is going to How much air how much of that air being drawn out will be sent? Back outside, and how much will be sent back? into the building and There is a reason [for] that now [you] don't have to have this here You could have that duct straight across and this also duct straight across so that these two are not [connected] now and that's certainly the way in the past it was it was achieved, but It's really expensive to do that, so if you imagine if you if you didn't have this connection here then All that air that you bought in brought in would have to be filtered heated and then cooled And then you've spent all that money in the in in the heating and the cooling Remember that the cooling is coming from that chiller and the chiller costs a lot of money to actually produce that cold water and also just to maintain all the system and Have a good maintenance regime for it And you've also got a very similar system on the heating side, and that's coming from the boiler that's the hot water is then coming up through the riser and entering into this heating coil first as well and and so you spend a lot of money on that [and] it's gone it's coming through and around the office ETC and And that air will then be collected, and if this wasn't here that would just send that straight back out to atmosphere so all that Conditioned air not all of it will have been of use and that would have been pushed straight back out, so By having these damper arrangements here you can divert some of that back in And it will usually depend on Outside air temp conditions for one and also the level of Co2 in the room or in [the] in the return duct here and if the conditions are right Then it will channel some of that back in and that means that The heating coil will not need to do as much work, or maybe the cooling coil Maybe the humidifier Will not need to work So you'll save money by by returning some of that air Back into the system obviously there will be some fresh air. It's usually about 10 percent of the [all] the air coming in the going around the system has to be fresh, but [there] will be Some set points in the BMs the building management system. Which will control all that and the controls experts will set that all up But we will look at some real examples of this and not in this video in this one obviously We're just covering what's happening inside the ahu? So one of the first points, I'm picking up there and really drumming on a bit and is These damages here. Let's just look at that from a better perspective So we've got the dampers here and These are all these will all be connected Via controls. I've in this example [just] mechanically interlocked them and so that as we open them weather will begin to close, so if this was a 100 percent open Then that means it's 100 percent fresh air coming in that's going off into the ahu And that also means that 100 percent of all the extract air is being pushed back outside because these dampers are now closed but So the the conditions are met and the temperature of the [air] coming back is Satisfactory and we can we can reuse some of this there the co2 in the room isn't too high so we can start to then close this and [we'll] Let us bring it to the up. Maybe 60 percent or something and That will allow if this is 60 percent then this is 40 percent. So that's going to allow 40 percent of the air going in will have already been around the office [and] 60 percent of the air coming in is now is chair, so that's coming in there. They're mixing here That's coming in then that's going this way So that's that air at the cold air and the warm return air is mixing here then it's being pushed off and out into the building and this is just the photo of one of the Control units for the dampers on they hate you and so this is being sent controls a signal to tell this to Change its position, and that's a small motor inside. Which is going to turn this and that causes the these rods to rise and fall either way and that will change if you imagine this can [change] the Position of this Rod here and on the inside [of] the duct is the damper and I'll just show you a real example here of that control unit and connect it to the dampers and inside there these [are] the dampers inside the actual unit and I'll just adjust the Rod manually myself and that will change the position of them and That will allow it to open [and] [close] [and] go you can see the mechanism there But that changes the amount of air coming in Okay, so the next part we're going to look at is the filters which are in these two components or compartments here? Now you'll notice there are two different types of filters This one here is known as a panel filter and this one here is known as a bag filter We can just pull that out now. We'll look at it. So the panel filter Is it's pleated [that] it goes across and it's it's got this very thin cardboard on it right outside Just to give it a bit sturdiness, and there's a wire frame inside, and so this is your first line of Kind of Defense to to filter [your] air and There is a surprising amount of dirt, and just muck that comes in with the air and you want to get rid of that filter out Before it hits the coils and also before it goes into your your fan is sucked in by the motor for the cooling And it's also pushed out onto the floors For the occupants for the tenants the office workers they're going to be breathing this air in so it's important that That air is cleaned and is conditioned in a correct Manner So the first line it will go through is the panel filter and I'll just show you what a real one looks like So this is a real panel filter taking that [ova], hit you [this] is clean this is Brand-new ready to go in you can see the color the colors really this kind of Green color [motive] the manufacturer and and the frame here [and] just give you an example here of How that would look inside the ahu in real life, so we've got four panel filters of different sizes obviously slightly different design here for a different manufacturer and also the The material that is [used] the thickness Or the thickness [of] of this filter material is what's going to? capture the the most dirt and germs ETc that's going through there and The age you designer may even even bring filter specialist in and they will advise you what? What filter material you should use there's some standards which you can look up and read as well but these filters will Become blocked over time as the more and more air that passes through there These filters will pick up all that dirt, and it will get to a point where the pressure drop [across] the filter Becomes huge because the fan is trying to pull this air through, and it's blocked by this let me just give you an example So this is what a clean filter looks like you can see the the metal frame there and the the Filter material Wrapped around it looks quite nice and then a few months later after Maybe a few days it depends where your building is If it's sucking air off of the motorway [or] the next with the industrial site Neck maybe [near] coal power station or something you're going to be going for a lot of filters, so this is What the dirty filter looks like only after a few weeks a few months it depends where you are like I said And you can see look at the amount of days, so this is just Pollen this is bits of skin. This is dirt. This is You know where where cars drive along the roads and they give off all the co2 And the tires degrade and [let] rubber comes off this is all coming in this is all collected on here, so This is why it's important that you have filters on your air streams and that you you clean these regularly just [make] sure that is not entering your building well into your equipment and also That the occupants inside are not breathing this in You'll also find some information on the side of most [Er] panels So you can see the size there you've got the product description and the company who makes it But you've got the size of the filter there this one's in inches Who the customer is I've just interested that quickly? But more importantly you've got the direction of airflow. So you know how to install [that] within the ahu How to slide that in so that the air will be passing through this way and out off Into the supply duct it's important to get that [round] the right way and just to show you a filter here and stops it a new one and Just show you the thickness of these and the materials they use so you can see straight through it the light passes free it's very thin changes in Density, but Yeah, it's very thin material the thicker the material the more you will capture, but then the higher your fans will [have] to work So the more you spend in electricity the second line of defense there is your panel your bag filters evil and These actually kind of these jagged edges, so the bags go back a certain distance [and] that they will change that and that changes if you imagine the surface area that it can capture So it comes along there at least and slide in and out the real Bag filter Insulation will look something like this in this example. You've [got] the panel filters almost directly coupled to thee and the bag filters there and if you imagine the airs coming through these these really kind of inflate as they Resistance to the flow of air and these will start to clean and capture all [that] That the dirt out of the air which we saw earlier and here's one of the bag filters [I] Just got out of one of the boxes just to show you the [soft] material It's made out of and it's construction. So these bags going back to capture all that air So this isn't how they look like inside. The aah you Can just move there the very light and you [can] just slide them out like this also Sometimes they'll just have these clips here, so you can't slide them out You just rotate these and you can just pull the clips off well Take the panels out by rotating these One way to monitor how dirty the filters are becoming is to install these Pressure differential sensors onto the sides [and] the panels this is just the manual reading so you can see here It's reading in Pascal's on the bottom and and into the water on [the] top and This will change as the the pressure increases across there, so There's no pressure drop at the moment, but as this goes down as the filter becomes more and more dirty it becomes greater or greater and so this is measuring the difference between the intake and the suction side of the across the filter and that's how you know how dirty is a Really good tip is to actually mark these so put a sticker or draw a pen or something to display What a clean filter my mark should be and where a dirty filter mark should be and that way When you do your walk arounds when you're making this team does the walk grounds you can go along and if it's dropped below say 150 Pascal's If it's going down to [two] [hundred] lit with a red dye then you'll know that you You should have changed the panel or the filters by now and then you can [get] the maintenance Regime in place to do that You can also automate this [and] if you've got the capability of a BMs system on-site a building management system Which is computer controlled version of you know your maintenance guys? then this will all be built into the system and It will give you alarm, and you can monitor and and then also do some analysis on that data as well so this is a digital reader here and you can see the supply side is being read for the pipe there or the Tube and Then this Tube is going [round] to the other side of the filters, and it's just a hollow Tube really Which is going to suck that in and it will take the pressure reading across there slightly different type And that is just basically taking the pressure reading across the filters and it will send an alarm and alert to the BMS that the filters are ready to be changed because the pressure drop has increased too much and Indicating that it is dirty Now the next point we've got here is the coil. So we've got the heating and cooling coil in this configuration and The Ahu you will come across in industry May be slightly different to this than right like I said only have a heating or just a cooling they may have a humidifier in Place ETc, so but for this example, we're just going to look at Having a heating and cooling coil there so With your heating and cooling coils obviously the heating one is going to be connected to your boiler or your heating system It could also be electric. It could be an electrical heater in here [certainly] for a fresh protection that's sometimes used and On the cooling coil here This is what's going to be connected to Your chiller your chilled water system And if you remember back to the beginning of the video that's what's coming off that riser [a] chilled water coming in and passing through and It's good to have this connected so that the flow The coldest water is coming in and the height is water going in And it's entering through the base of the coil and passing through you'll get much greater efficiency [out] [of] this because it's going against The Force of Gravity so it gives a little bit extra time and just to give off its heat if you can think the other way then it's got that extra momentum of Gravity, so It will pass through there and not all of it will give up all of its heat [but] this is maybe a step Advanced step and we don't need to worry so much [about] it yet Let's have a look at How the cooling and heating coils work? so if I change the view here Apology's is going slightly boxed as my ram is starting to run out on this computer at the moment and but as you should be able to see here the coil is configured so the Pipe inside here runs in this configuration [all] the way around until until [ak] well in fact it runs the other way, but Same difference [and] to let exit So the pipe is going through leg and that contains inside there, and is the heat heated or cooled water and Maybe steam we could have steam on the on the hot side as well on the heating coil and between there all these thins now these fins a Usually something like aluminium, and they're incredibly thin they really are [very] fine sheets of metal very [delicate] as well if you knock them it will dent them and it will damage them You can get some combs to bring those out as well But the fins the purpose of these is that the heat or the [Kulfi] inside these? if it was the air just rushing over these over the pipes then it would only have surface area of That pipe if you imagine, it's the air coming in here and hitting that pipe it will go around and continue And it's only going to take the heat or cool off of that surface there And you'll also have these large gaps here where the pipe? There is no pipe, and so the air will just pass straight through and will not touch that So to improve the heat transfer of this heating or cooling coil we put these fins all the way across the pipes, and that allows the heat in there to To transfer and and conduct through the these fin sheets of aluminium May be stainless steel or something but that travels across and that allows that air That's passing through to capture that heating or cooling energy Thermal energy off of [these] things and and bring that away, so you'll get better control and better conditions You'll be able to reach your heating or cooling [set] points through the use of this so just to show you an example of how [a] real heating or cooling coil look and here we've got the connections coming in and It's just entering there, and you can see these Coils are just coming around like that They're the tubes are a lot thinner than the ones that I put in the model obviously [that] is just for Explanation purposes to get build your understanding. It's a lot easier to visualize it that way so these very thin tubes actually pass all the way around and You [can] see these really really thin sheets of aluminium, or stainless steel running through there likes like so So there's another real life example one of the ahs and [just] [looking] there for the viewing window and And you can see there just how thin these are they're very Closely packed together this one's actually a bit dirty. They do need to [be] cleaned periodically especially if it's the cooling coil because the Air will Condense [onto] [this] and that will make it wet and that means that if your Filters are not capturing everything That dirt and dust in the air will actually stick to that, so you Get dirty coils, and you [will] clean it every so often This is a heating coil. We can just see there the flow coming down here entering into the [coil] and again see just [and] all seeing these pulls out and see if [he] [dents] there as well and this is Being damaged slightly during the maintenance. You can see the cause as well and The cooling cause might also be provided Cooling cool by a refrigerant system, and they were going to look something like this These are just the thermal expansion valves. They're running down with the thermal bulb down at the bottom here and these are just running into the coil on the inside and The core on that one will look a bit like this with the branches coming in And separating off as a few [thins] on this one instead but Just going back there you can see the refrigerant lines coming in and splitting off and going to each of the The coils that are coming and looping around there now [underneath] the coils, you're probably going to find that there is drain and drain lines coming out And I haven't drawn it on this example here, but I will show you what they look like in the real world so they're going to look a bit like this with the drains coming out and You go into you bend there to stop the flow coming back And that just comes down this pipe which is on an incline and heads down to the drain and Looks like this one hasn't been installed too. Well as most of it. Let's go over the floor rather than down the drain, but it [was] it was a good a good attempt I guess and here's another example, so in the base of the Ahu you've got this drain here And that will just collect up All the moisture that comes away the peak of someone that can actually be quite a flow rate Where the water is condensing out of the air and that [is] then channeled and goes off back to drain? okay, so next we're going to look at the driving Force of the air as being pushed around sucked in and pushed around the system and then rejected and that is of course the [fan] units here now this one here have [actually] brought out what the fans just outside the casing just so you can see that and Fact let's change that position just there a bit There we go now let's rotate that a little bit There we go. That's better so you can see here we've got an induction motor and [that's] bolted down usually to a frame because these are pre-built systems and That's going [roll] off to the pulley and then this is put onto a belt drive and the end of the belt. This is a rubber Wire frame mesh belt and that goes off to another pulley which is connected to the fan blades inside here You'll notice that this fan here has backwards Curved fans there are [a] lot [of] different designs. You can have this is fairly efficient There's a new type of fan out. Which is actually much more efficient than this, but I like this one Just because you can you can really? Visualize what's happening there, and I have couple d. So that we can actually? As we rotate the motor you will see there that that Rotation is being transferred through the belt the belt is then driving that pulley and the pulley is then? Driving the fan. [they're] driving the fan blades so as that Spins and it goes faster [and] faster and faster, and [that] draws that air all That air is being Traveling along the duct there, and it can't be it's being sucked into the sides here on the back and the front as well, so as that induction motor there and the pulley spins it pulls all the air in and That starts to fill this void the back of this one is obviously pushing that that air it's coming around and as it's doing that it's kind of being flung off the side here you measure like a Centrifugal force if you spin something it wants to go it wants to go out So as this occurs. It's following a longer curve, and it's being shot up, and this is this is pushing it and as That comes around to say here It's a full swing and it gets thrown out and there's more air coming around this way is being pushed as That builds up the pressure of a static pressure in this duct here and that drives all that air out So that pressure difference calls there, so this would be a negative pressure or a lower pressure And then this would be a higher pressure because it's the air here is being compressed Into this [this] duct here, and this is being sucked in so it's a lower pressure going in Now I mentioned the belt drive there These belts also need to be replaced periodically they will break And they will wear down in fact I've got an example here so this is a broken [V] belt used on them one of the pages and You can see there. It's just completely snapped and this has had to be replaced If you've got the good control system in the on the BMS system. It will pick up that Sudden Loss that step and and it will activate act on that, and it will stop the motor from running obviously, you should have a good maintenance regime in place to Plan preventative maintenance to actually stop this occurring, but it will happen from time to time Now this is what a real Induction motor or fan looks like this is pretty much what I based my on you can see the designs like [the] different but I'm a little astray [ssin] purposes for our one and [they're] here. You can see you got the power supply coming in into the induction motor This cable may may go off and that may come out there Will be fed by one of these there will frequency drivers variable speed drives which we talked about earlier [and] that controls the speed Of the induction motor obviously they're going to the isolator and that can be menu controlled But it should be in auto mode you'll see on the panel there. Maybe we'll do another video on that actually and That goes also to the BMS. So everything's automated and can respond in real-time And so that's the power unit there And then this is the pulley here, this is the drive shaft which is being spun by these Magnetic field inside this induction motor and That's rotating these pulleys and Driving this pulley here. Which is directly coupled here to the The fan blades inside this this fan here, and that's where the air is being sucked in here And then it's being pushed into the duct and off off into the space [here's] that fan in a video here [just] so you can see it in the kind of real life There we go. We got the fan there you also get these data plates on there And you can just see the top of the pulley there as well There's also a data plate on top of the motor there as well, and that will tell you the kilowatts the amps Etc That's going on there now the returning fan works very similar to the supplier one just in reverse [so] [it's] sucking the air [out] of there and Just again done a simple explanation here of how that would work So once the air is being brought into the building Just came in it's passed through these dampers, and it's controlled the amount of fresh air that can be brought into the space And it's come in the BMS has decided How much air can be reused there and recirculated you could also put this [on] a manual system? and change it seasonally if you don't have a bMs or the BMS for some reason isn't working but Obviously the more you can automate the better the controls will be and that will then bring that in And then you need to filter that Here we've got two layers of kind of filtration protection Then we're going to go through we're going to heat It heat the air up and cool it down or heat it or cool it ETc. Maybe change that to change the psychometric properties of the Air and then That what's been pulling all that air this whole time is this fan there and that then drives this and sends it off off? into the space into the offices where the air is then dumped Can it conditions the space inside the building? Keeps all the occupants happy and then returns back here through this way Now schematically drawing of how an I hate you will look with something like this so in this example the air is flowing in this way and It's going through the filters the fan is pulling that in You've got the bag filters there And then it passes into [the] heating coil you can see that because it's a plus because it's adding energy Into that stream of air next will pass directly into the cooling coil and you see that because it's got a negative because it's taking energy out [of] that system and Finally here. We got another point. Which is the humidifier? something I didn't [include] in my one there not in every [I] hate you and This one has got a humidifier Looks like it's a steam one because it's got a meter there as well. That's going through could also be water Let's have a look so this is a Humidifier here, so it's got water coming in and it's just spraying this out these small induction motors here, I Just spraying that water [out] the very very fine mist And and as that sprays out, and it creates the mists of that then goes off, and that's what hugh? hugh millet II to the air increases the water content of the air Another way to do it would be through so like this which is an evaporative humidifier You [can] go for a steam system as well, so it is there's many ways you can [actually] do that Just to add moisture to the air and it depends on the critical environment or the [environment] if it's critical [one] up It used to be in many offices this would put it in there to control the kind of the static in the air But more and more this is being switched off. It's very energy intensive So it's being switched off, and there's various guidelines to tell you where when you can and can't do that And so [I] would recommend you research that before switching these off Now I've talked a lot about the BMS system the building management system, and this is just a screenshot from a typical BMS system of Over actually what the system? We drew why had looked at earlier, and when I made a model of and So this is what it might look like on the computer screen There probably a bunch more readings around here I've actually taken some of these out just to clean it up and let you see what you might be measuring so here again We've got the dampers in their position, so it's it's measuring these We've got a measurement here for the outside Enthalpy We've also got the mixed air temperature here the fresh air air velocity coming in so you can you can measure? how many here is meters per second are coming in if you know the [the] size of the Ductwork then you can obviously calculate the volume flow [rate] coming in here we've got the mixed air temperature, so This will be different from the outside air temperature you usually have another temperature sensor here. Just showing you what the temperature outside is and coming in Then we're going through the panel filter which we can see here is clean there's the pressure drop across it, but also the fans are not on so that wouldn't really pressure up anyway and Then we've got the bag filter here next we've got a frost sensor here, so this is a temperature sensor, and that's detecting if the Air coming in is Probably around [five] degrees Celsius that that's the typical kind of alarm setting So if it drops below that then this heating valve here will open and that will Heat the Air it will supply heat to it So here is a frost temperature sensor. You can see there. It's set at Five degrees, so if it temperature gets to that point it will kick this on this is an electrical one So it's just going to add Heat the electrical elements inside and that will warm that air up in there and bring it above five degrees because if it got too cold, and it hit the pipes and that could Cause your the the pipes within the coils to burst And obviously you'll leak that Fluid into the air and you don't want that to happen, so [you've] got some protection here And then that comes off and [goes] Into the cooling coil and you can cool the air down [here], or change the humidity Using this one, and then that's being sucked up [C] by the fan and being pushed off Here you can see that the it's measuring the supply air Relative humidity So you've got some measurements here for the temperature and also the humidity and it's also measuring the enthalpy here So this is a more advanced control system Which we won't talk about so much in this video [we've] got a pressure sensor here. This is reading minus figures, but the fans aren't on at the moment probably some calibration anyway, and We also got some run hours here for the fan. So you know? How how long they've [been] running for and then you can do [your] proper maintenance and also do some energy analysis ETC? And know your time value of money for your plant equipment. So you know that every? X amount of hours these fans will need to be replaced or maintenance will be carried out of them So this is a very good idea Vms to log these if you're doing it manually then you have to guess you might not get value for money like that and this is the Calculated supply air temperatures [and] the set points as well So this is what the air will try this system will try to achieve [so] the air coming in It's going to be These set points here Again on the extract we've got the extract air temperature and relative humidity relative humidity there and also the temperature and that is the extract enthalpies the amount of energy being drawn out of the space there and then again that is pushed either Out up straight out the exhaust air or [it] is mixed back [around] to the system here Just show an [example] of a temperature sensor here, so this is bolted to the side of the unit maybe onto the top of it and this would be various ones, and there's a Rod coming Inside the unit they're taking measurements of the temperature of the air And you may have noticed at the top here this tube sticking out? Sticking through the top that is your temperature sensor right there that's taking the measurement going on [onto] this heating coil here And will dictate through the controls. How that should operate in response to that Okay, that's it for this video. Thank you very much for watching [hope] you enjoyed it. Please like subscribe and share and If you have any questions Please leave your comments in the section below more than happy to assist and also give me some recommendations. What would you like to know? What would you like to see me make next? Yeah, I'd really appreciate your feedback obviously we're on Facebook Twitter google+. I also got a [website] which is the engineering Mindset calm You've probably seen this written out throughout the video several times Yeah, check us out. Thanks very much
