Chiller Flow Rate Calculation – HVAC Training Practice Problem – HVAC Design – HVAC systems

hello and welcome to this video brought to you by 
elite educational and professional academy now in   this current video we do have a very interesting 
topic it's a very elusive subject especially for   hvac professionals working in the construction 
or the consulting end of the industry more   specifically in this video i'll be walking you 
through a hands-on application a hands-on example   for how to calculate the chilled water flow rate 
for your hvac chiller system now if you're not   familiar with the chiller system what it is what 
how it works what are the various components we   do have multiple videos on our channel just make 
sure that you take a look at the suggested videos   and the videos at the end of this current video 
in which you learn about the various components   and everything that you need to know basically 
about how the system works and how it operates   now in this current video like i've mentioned 
we have a specific example and one of the most   important design aspects for chilled water 
hvac system which is the chilled water flow   rate how do you calculate the chilled water 
flow rate for your chiller plant such that   you are able to provide the required amount of 
cooling requirements in order to satisfy the   design criteria for your space 
so i'll be showing you an example   on the how to calculate the required chilled water 
flow rate for your hvac system now at this point   make sure that you click subscribe in order to 
stay tuned for the upcoming insights and releases   addressing various aspects of the industry now 
within the application within the example i'll   be giving you a practice problem that you need 
to do in order to make sure that you are familiar   with the plaque practice and the application once 
you're done with the practice problem make sure   that you put the answer in the comment section 
below in order for you to compare it with the   rest of the channel community members just to 
make sure that you are comfortable and familiar   with the calculation steps and process so let's 
just simply get right to it and jump into the   example so we're going to have an example on 
the calculation for the chilled water flow rate   let's say you have a building we're going to 
sketch a building to represent a real life   um scenario and this could be any building it 
could be a four-story building 10-story building   15-story building respectively our main concern is 
just simply to properly apply the principle of the   flow rate calculation for your application because 
it's a very important concept and principle   for any engineer especially an hvac engineer in 
the field let's say this is basically a building   and for my building i'm going to 
keep it simple i'm going to have   a single air cooled chiller for 
example at the top of the building   and let's put some words for this current 
problem let's say i have a current building   which requires 350 tons of cooling the complete 
building requires 350 tons of cooling to meet the cooling load requirements for the application now the first step 
that you need to do for any hvac design   is basically conducting the proper load 
calculations that's the first step which   is actually the initial step that you need to 
do before you are able to actually conduct the   fluorite calculations and do anything related to 
further design application you need to be able to   find this value that's the first step any designer 
is going to do now if you're not familiar with the   load calculations what are cooling load 
calculations how to go about the process   in the description of this video i've left you 
a coupon for 70 off on one of our master classes   on the academy elite educational professional 
academy that you can use to grasp the concept   and learn how to go about it because this is an 
essential necessary step within the field of the   hvac let's assume that you're familiar with load 
calculations you are able to obtain the required   load calculations for various applications 
and you got to this point where you have   a building and for your building you managed 
to find out that you need 350 tons of cooling   to satisfy the requirements of your space cooling 
load requirements so the question is what is the required chilled water flow rate that will 
satisfy the cooling requirements and provide me   with that 350 tons of cooling let's put some 
colors here now take a look at the chiller   i'm going to use blue just to represent the 
supply line in this case for every single floor   approximately we're going to have such a civil 
representation where the blue line represents   the supply of the cold water and the red line is 
going to represent the return line now keeping   them quite far away from each other just simply 
for visual purposes but normally they are quite   um closer than the current representation but 
just simply to help you get the idea so we have   a supply line we have a return line and the 
application would require a specific flow rate   right the cold water that should be flowing 
in my network in order to provide me with my   cooling requirements so the first thing the 
first formula that should be applied or should   be kept in mind is the basic heat transfer 
formula where you have q equals to m dot cp   delta t we were just simply brushing up on this 
formula to help you recap where it came from now   in the previous video explain with details 
what the importance of the formula and how   it leads to the flow rate calculations 
now this is basically the q is for the   heat transfer right m dot is the mass 
flow rate cp is basically the specific heat capacity of water and delta t which is an 
important value here which is the temperature   difference between the supply and return lines 
these lines basically the supply and return the   blue and red now delta t this value like we have 
mentioned in the previous video delta t is going   to be 6.67 degrees celsius for commercial building 
or for a residential building within a specific   region and for every every single region within 
the world you can refer to your current standard   in order to be able to identify your delta t 
which has been documented through trial and error   and experimentation this equals to 12 degrees 
fahrenheit now the conversion is quite simple   you can just simply apply the conversions on the 
side to go from degrees celsius to fahrenheit   so what we need to do now this formula in the 
application is simplified such that we have q equals to the tons of cooling times 24 over delta t now this q do not confuse 
it with the heat transfer this is going to be   the gallons per minute okay you can just name it 
whatever you want to name it this formula here for   the genetic formula for the heat transfer has been 
simplified we're going to avoid the simplification   because we just simply care about what we use in 
the practice to actually calculate the acquired   flow rate this formula that theoretical formula 
the fundamental formula for the heat transfer   has been simplified in order to have this formula 
where we have q is basically gallons per minute in   this case tr is the tons of cooling that we have 
this current problem which is going to be 350 tons 24 is basically a conversion factor as 
we simplify the formula mentioned earlier   delta t is going to be in fahrenheit this 
formula is important to highlight this formula   is for the english system of units pounds 
gallons per minute feet square feet cube etc   if you need the si system of units where we have 
meters seconds watts kilowatts you can refer to   the previous video i'm going to put the link in 
the suggestions at the top you can refer to the   previous video and you can use the formula 
presented in there as well depending on the   application if you need the english system of 
units you can use this formula if you need the   si system unit you can use the other formula 
that we have mentioned in the previous video   now it's a matter of crunching numbers so 
i have q which i need to find it equals to   tr which is the tons of cooling grease is going 
to be 350 tons times 24 which is the convergent   factor divided by delta t which is this 12 
degrees fahrenheit now delta t is obtained   from standards and application for the commercial 
building that i have in front of me right now   delta t is equal the difference between the 
supply and return is 6.67 degrees celsius which   equivalent to 12 degrees fahrenheit now if you 
crunch in the numbers 350 times 24 divided by 12   you will have 700 gallons per minute that would 
mean in order to provide 350 tons of cooling   in order to provide 350 tons of cooling for my 
building i need to deliver within the network that   we have i need to deliver 700 gallons per minute 
of chilled water so this is basically that the   flow rate that needs to be delivered by my piping 
network for the chilled water system in order to   meet the cooling load requirements now let's have 
a small example for you that you to practice on   what i want you to do is basically apply the 
previous steps for the current example and in   this example we're going to do you're going to 
apply the same steps you're going to calculate   the value and after you find the value go ahead 
on the comment section leave your answer to check   and compare with the rest of the channel members 
whether your answer is correct so let's do   let's do the question and you can apply 
what we have talked about so far and you   can just simply map the steps and check 
if you understood the concept assume you need 500 tons of cooling requirements requirement for 
a commercial building okay   now delta t is going to be 12 degrees fahrenheit 
i'm going to make it straight forward for you this   value of delta t i've given you the value but 
based on your country based on the region that   you're at you should refer to the standards 
within the handbook such as ashrae handbook   or different standardized approaches within your 
country or region because different parts of   the world they have different applications 
for delta t however they are documented in   handbooks that you can just simply get such as 
ashley hambrook and you can open it and take a   look at your current country or region and what 
is the utilized delta t but for this current   application i'm giving you this value delta 
t which is going to be 12 degrees fahrenheit   okay and i assume you need 500 tons of cooling 
requirements for your commercial building   delta t is 12 degrees fahrenheit 
that question would be calculate the flow rate for your chilled water system which is needed in 
order to satisfy the cooling load requirements   so like i've mentioned you're going to apply 
the same steps that we have covered earlier   and check if you are familiar and you are 
comfortable with the concept after doing so   you are going to put your findings in the 
comments section to check basically that you   are comfortable with the requirements you 
have applied the steps correctly and most   importantly you have got the correct answer 
so at this current time if you have found this   explanation and the video beneficial just make 
sure that you click subscribe and you like the   video in order to stay tuned and updated with 
upcoming um insights on so we have completed the   example now you should be familiar with the steps 
that you need to do in order to properly size   or design the acquired chilled water flow rate 
for your chiller application now for the practice   problem that we've talked about towards the end 
of the example make sure that you solve it you   can write it down on a piece of paper follow the 
same steps once you're done leave your answer in   the comments below in order to compare and make 
sure that you are on the right track also i've   left for you in the course description a coupon 
for the master class on load calculations like   i've mentioned is a very important step initial 
step for any part of the hvac design you should   be familiar with the process of conducting load 
calculations it's a necessity for any practitioner   in the hvac discipline so i truly hope that 
you found this video beneficial you you're   more comfortable now with the steps that you 
need to follow if you are on track and if you   found this video beneficial make sure that 
you smash that like button and you subscribe   to the channel and stay tuned for the upcoming 
videos on various aspects of the hvac industry

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