Howdy there, guys. Paul here from TheEngineeringMindset.Com. On this video, we’re going tobe discussing rooftop units. Arising, what’s anRTU, the place are they used, how do they work, the unique varieties, as well because the componentsinside, equivalent to warmness exchangers, filters, lovers, ductwork,grilles, air hoods, et cetera. For those who like the informationyou see on this channel, and that i fairly hope you do,then it can be handy to preserve your schooling going byheading as much as Danfoss studying who have kindly subsidized this video. Danfoss need to encouragepeople all all over the world to gain knowledge of as much aspossible about engineering. So that they developed a freeonline finding out platform packed full of publications onpretty so much every possible engineering matter,including extra classes about rooftop units.All you have to do to getstarted is click on the hyperlink within the video descriptionbelow, create your free Danfoss finding out profile, andthen opt for your top notch. Pop engineers quiz, what does a package airconditioning unit imply? Inform me your solutions inthe feedback section beneath, and i will expose the answerat the very end of the video. Ok, rooftop models, as thename suggests, rooftop units, or RTU for brief, arelocated on the roof of stores and small industrial buildingsto furnish air conditioning to outlined areas. These are packaged air conditioning units, and they are so wellknown becausethey are simple, compact, self-contained, all-in-one HVAC items. Their reason is todistribute conditioned air within outlined areas of a constructing.Rooftop items are linked to ductwork which provides a definedroute for the conditioned air to travel along. Now in our final video, we looked at air handling items, or AHUs. I would motivate you to watchthat if you haven’t already. Hyperlinks are within the video description under. When you’ve got watched that,you’ll as a rule detect that these models are very identical. Rooftop items are a style of air handler.The foremost difference is thatthey are ordinarily extra compact, and they’re at all times established on the roof. So they have to be morerobust and weatherproof to take care of things like solar,rain, snow, wind, et cetera. Additionally, AHUs will oftenbe connected to important vegetation similar to chillers and boilersto provide the heating and cooling, however RTUs are self-contained and have everything theyneed multi functional unit. That’s why they may be calledpackage air conditioners, and we are going to appear insidesome units just shortly to realize why. There are lots of forms of rooftop items, and we’ll look at fourdifferent usual versions starting with essentially the most normal. This first unit is freshair simplest so that signifies that there isn’t a recirculationof air occurring. It takes one hundred% fresh air and stipulations it. The return air is most often removedby an external exhaust fan to balance the air pressurewithin the building, but we is not going to duvet thatpart in this video.First, now we have the housing. This needs to look after all themechanical and the electrical equipment within the unitfrom the sun, wind, rain, snow, frost, et cetera. There can be some accesspanels constructed into this to enable engineers toaccess the accessories inside of and participate in protection. At one finish, there wouldtypically be an air hood. This is the place the outside ambient air might be drawn into the computing device. The hood is formed this way tostop water, snow, and debris from getting into into the unit. There’ll usually bea mesh throughout the inlet of the air hood which willprevent flora and fauna and objects from getting into, as thiswill purpose blockages and injury the fan. The following thing we mightfind are some dampers.Now not each unit has these, butnewer models commonly do. These are in actual fact sheets ofmetal which rotate together. They open wholly to allowair to enter the unit or they almost sealthe unit and prevent air from coming into or leaving. Some dampers can fluctuate their open function to someplace between fullyopened and thoroughly closed, mainly if recirculation is used, and we are going to seem at that later in this video after this basic model. After the dampers, we will in finding the filters. These will mostly just slideout from the provider door. Their purpose is to cleanthe air with the aid of shooting the dust and the dirt which iscontained within the incoming fresh outside air. If we would not have filtersinstalled, then the fan, warmth exchangers, mechanicalcomponents, and the ductwork are all going to slowlybe blanketed with the aid of the dirt, and it is going to curb the effectiveness and the efficiency of the computing device. If an excessive amount of dust buildsup on these add-ons, then it is eventually going to lead to the failure of the desktop. After the filters, we are going to have some coils. These coils might be usedto cool or warmness the air by using including or doing away with thermal vigor.Depending on the place in theworld the RTU is placed and the ambient stipulations it faces, some models shall be cooling most effective, although infrequently theywill be heating most effective, and a few can be heating and cooling. If the unit is cooling simplest,then it could by and large have a single coil which is connectedto a refrigeration unit. If the unit is heatingonly, then it will both be related to a heat pump, a fuel burner, or an electrical heating aspect. If unit is heating andcooling, then it should both have two warmth exchangers, whereone might be a cooling coil which is attached toa refrigeration unit, and a good way to provide the cooling, and the opposite will likelybe a true warmness exchanger which is attached to a gasoline burner, or it might be an electricalheater to furnish the heating.However, a unit mightprovide each heating and cooling making use of a single coil whichis connected to a warmness pump. Now we have blanketed heat pumpsin a prior video. Hyperlinks for which are in thevideo description below. Most models will use a refrigeration approach to furnish the cooling. The compressor, condenser,fan, and controls are most likely placed on the rearof the unit or at the facet, and these will likely be used toreject the heat and hold it faraway from the intake and the conditioned air which is inside the unit.After the coils, we will to find the fan. That is by and large a belt-drivencentrifugal sort fan, but it surely can be an EC type fan that are more vigour effective. The fan pulls the air in from external then by means of the dampers, filters, coils, and they will push thisthrough the ductwork to be dispensed around the constructing. That’s our most basictype of rooftop unit. So what else might we discover? Some models mightrecirculate the interior air for a return ductwork procedure. This is used to saveenergy, primarily in winter when the external air may be very bloodless and a return air could be very heat.We can use this to reducethe heating load through mixing one of the crucial heat return air in with the cold fresh air consumption. In this design, we discover areturn air damper within the unit. This may work in syncwith the intake air damper and the two will range theirposition to alter the blend of how much contemporary airand how much return air is passing through the unit.There will constantly be acertain amount of recent air coming into into this typebecause or else the constructing would without difficulty refill with CO2 and create an extraordinarily unhealthy atmosphere. Because the damper opens, thesuction of the fan will pull air in through the ductwork. When the damper closes,no air will be drawn in. A different version we will come across, and this sort may be very long-established,in this design, we again have the return air damper, but this time one of the vital air or all of the air will also be rejected to atmosphere. The temperature of theoutside air and the return air and mostly the CO2levels of the return air will dictate how much air might be rejected and how much will bemixed and recirculated. On this form of unit, whenthe outside air temperature is beneath or practically thedesired indoor air temperature, one hundred% fresh air can beblown into the building, and none of it is going to be recirculated.All of it is going to be rejectedas the cooling demand is met. That is referred to as free cooling cycle or an air facet economizer cycle. The ultimate variation we’lllook at has a warmness wheel built into the unit. This is developing in popularitywith the growing want for energy effectivity inbuildings to slash CO2 emissions but additionally vigour and utility expenditures. This unit first pullsair in through the hood. The amount of air enteringis controlled with the aid of the damper. The air then passes througha filter to capture the dust and the dirt and preserve thesurface of the warmth wheel. It will then pass by way of the heat wheel. The warmth wheel is a rotatingheat exchanger which picks up the waste warmth or CoHP fromthe return discharge air, after which switch this overto the incoming contemporary air with out the 2 air streams mixing. These warmth wheels arenot entirely airtight. So a bit of bit of air mixing will occur. The warmth wheel is usedto offset the heating and mostly cooling demandwhen conditions are right.This may increasingly keep vigor,as good as utility bills. After the warmness wheel, the air flows by way of to another filter. Simply earlier than the filter, we have now a damper on the return air circulation. This permits us to recirculatesome of the return air into the fresh air,and the quantities range by utilising the dampers. Not all warmness wheel RTUswill have this feature. Some will use only a hundred percentfresh air consumption and extract. If the unit does not havethe choice to recirculate, the unit commonly will nothave a 2nd filter again here. After this, the air will flowthrough the warmness exchangers so we can warmness or cool theair to the desired temperature.The fan will then distributethe air via the building by way of the ductwork to thedesignated areas. The return air is thenpulled back into the RTU for the return ductwork. Once it re-enters theRTU, it has the alternative to both recirculate one of the vital air back into the contemporary airintake, or else it’ll all cross by means of a filter andthen by way of the heat wheel to recapture the waste warmth. After the warmth wheel, wemight find an extract fan.Otherwise, the pressurecaused with the aid of the most important deliver fan will drive the air out in some designs. The air then passesthrough the extract damper which is used to differ thevolume of return air mixing as good as the pressureinside the building. After that, it passes througha grille which simply stops objects and flora and fauna fromentering into the unit. It will then be ejected fromthe method into the atmosphere. Alright, before we wrap thingsup, I just want to remind you to signal up on your freeDanfoss studying profile. Doing so, will get you accessto over 1,500 e-lessons including a couple of about rooftop units. Go supply it a are attempting now. Links are in the video description below. Engineers quiz answers. On the establishing of the video, I requested you what does the term packageair conditioning unit mean.The answer is that packageair conditioners incorporate all of the predominant add-ons inside one casing. So that is the enthusiasts, thefilters, the cooling and heating coils, the compressors,the controls, et cetera. The entire approach isprefabricated into one package deal. It comes from the brand, and will also be speedily established as one unit. Ok, guys, that’s it for this video. Thanks very so much for watching. I hope you enjoyed thisand it has helped you. If that is so, then please don’t forget to like, subscribe, and share, and leave your questions inthe comments section beneath. That you would be able to also follow us onFacebook, Instagram, Twitter, and TheEngineeringMindset.Com. Once once more, thanks for staring at.