Data Center Cooling - how are data centre cooled cold aisle containment hvacr

[00:00:00] Speaker 1: this is a data center they are located all over the world and are filled with servers which process and store all the online information we use processing all this data consumes vast amounts of energy and that produces a lot of heat so how do engineers control this heat that's what we'll be covering in this video which is sponsored by danfoss danfoss provide a range of solutions for data centers and they've gathered a huge collection of free resources at their data center hub you can watch informative videos read case stories and learn all about the different data center technology they have available including three curated videos just for you about sustainable data center cooling solutions oil-free technology and heat recovery do check those out i'll leave a link for you in the video description down below every time we stream a video back up to the cloud or even browse the web we rely on servers to process this at a data center these servers consume a lot of electricity to process and store all this data all of the energy consumed by the server is converted into heat and this heat must constantly be removed otherwise the circuit boards will overheat and destroy themselves removing all of this heat consumes additional energy some data centers are purposely built in cold parts of the world to make use of the free natural cold air some have even been trialed underwater to try and reduce the energy consumption for cooling data centers still need mechanical cooling so let's see how they work have you ever been to a data center or do you have any tips for improving efficiency if so let me know in the comment section down below if we look at a typical simple data center we find the server racks within the room and these are typically installed on a suspended floor around the perimeter of the room we find crack units which stands for computer room air conditioners these crack units suck in the hot exhaust air from the servers into the top they then cool this air down and push it into the void under the floor the floor tiles are made from thick solid materials which contain the air within the void some of the floor tiles have grills built into them which allows air to flow through them these grills are strategically placed near the servers so that the cold air can exit the void and be sucked directly into the servers the servers have small fans installed to help move air across the circuit boards and cool it down similar to your pc or laptop this air will carry the unwanted heat away where it will be sucked back into the crack unit and removed from the room when it comes to crack units we have two main types chilled water and direct expansion we also have upflow and downflow which indicates the direction the cooled air flows downflow is the most common so we will focus on this type smaller data centers will often use direct expansion units where an internal compressor pushes refrigerant around the system a fan moves the hot air over a heat exchanger known as the evaporator the refrigerant flowing inside the evaporator absorbs this heat so the air leaves cooler and is pushed into the void under the floor the refrigerant flows to the condenser unit located outside a fan blows air over the pipes to remove the heat from the system the refrigerant then returns to collect more thermal energy by the way we have covered the basics of refrigeration systems in detail previously i'll leave a link for you in the video description down below to learn more larger data centers will use chillers either water cooled or air cooled type with air cooled systems we find the chiller installed externally this provides chilled water to the crack unit which flows through a heat exchanger to pick up the unwanted heat from the air the fan moves the hot air over the heat exchanger and once the heat is removed it is pushed into the void under the floor the water returns to the chiller with the heat it collected it enters the evaporator where the heat is it is transferred into a refrigerant the refrigerant removes the heat from the water and cools it down the water cycles around again to collect more heat the refrigerant flows to the condenser where fans move ambient air over the pipes to reject the heat to the atmosphere the refrigerant then flows back to the evaporator to collect more unwanted heat from the water with water cooled systems we find the chiller installed internally with a cooling tower located externally the chiller sends chilled water to the crack unit to collect the unwanted heat and then it returns this to the chiller's evaporator a refrigerant inside the evaporator collects this heat and transfers this to the condenser another stream of water is flowing in the condenser known as the condenser water this absorbs the thermal energy and sends it to the cooling tower from here the water is usually sprayed into a stream of ambient air which removes the heat and cools the water down the water then returns to the condenser much cooler ready to collect more thermal energy we can also get dry cooling towers which are less efficient but the condenser water simply flows through a heat exchanger with air blown over this to remove the heat instead of the water being sprayed into the airstream by the way we have covered how chillers work in great detail previously links for that in the video description down below some crack units will be connected to multiple cooling systems to ensure there is always cooling available even if one unit was to fail some data centers also connect alternate crack units to different cooling systems to ensure resilience newer data centers built in cooler climates do not use refrigerants they instead will use free and evaporative cooling in this design the outdoor air is sucked in through some filters evaporative coolers then spray water into the airstream to cool it and humidify it the air then flows directly into the server room with the hot exhaust air being separated and extracted back out to the atmosphere data centers with refrigeration systems can also make use of free cooling when the outdoor air is cool enough for example an auxiliary air-cooled condenser can be fitted which uses fans to remove as much thermal energy as possible from the condenser water before it reaches the chiller other designs will allow the chiller to be bypassed altogether with the chilled water exchanging thermal energy to the condenser water via a plate heat exchanger this only works when the outdoor air is cool enough for efficient design we need to ensure that all the servers are facing the same way so that they all suck cold air in the front and blow hot air out of the back otherwise the exhaust of one server will be sucked into the inlet of another server we need to therefore also ensure that floor grills are only installed where cooling is required in this case only at the front of the servers not at the exhaust side not in open areas or in front of empty racks we also need to ensure that the airflow through the grills are balanced otherwise the grills nearest the crack units will vent all the cold air air and the rear units will receive very little the grills need to be located near the front of the servers otherwise the cold air will bypass them and head straight back to the crack unit the void needs to be kept clear of objects and unused cables which will otherwise obstruct the flow of air when several rows of servers are installed then the problem occurs where the hot exhaust of one row of servers is sucked into the next the temperature increases with each row which is very inefficient we would need to provide even cooler air just to keep the final server cool enough obviously this wouldn't be very efficient so instead we arrange the rows so that they are facing front to front and back to back this way we only provide cold air to the front of the servers and the hot exhaust the front of the server isn't sucked into another server this creates hot and cold aisles we need to ensure that empty spaces in the servers are filled with blanking plates this will prevent warm exhaust air from recirculating additionally the fans in the server racks will cause a negative pressure region at the front of the server and this can draw warm exhaust air down which can then be recirculated back into the server for existing data centers one of the best designs is to use cold aisle containment this is where the cold aisle is covered with a roof and the end of the aisles are sealed with doors this puts a physical barrier between the aisles to prevent mixing and recirculation newer data centers will likely use hot aisle containment in this design cold air fills the room and the hot exhaust air is contained and separated with a ceiling this air is then drawn back into the crack units check out one of these videos to continue learning about engineering and i'll catch you there for the next lesson don't forget to follow 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