Question #1 and first of all I would never use the weather channel I would be using ACCA's Table 1 Manual J. There are still missing factors are walls exposed or against conditioned space and how high are they,are their any windows in the room and what u factor are they and direction do they face, is the 6th floor below conditioned. Is there a ventilated attic space above, and what r value exists between the ceiling of the server room and the roof, Is the 12,000 watts from the computers and 200 watts from the lights(is lighting fluorescent or incandescent? ballasts put off heat) the only loads from electric in the room or are there others fan motors,timeclocks, etc.
But from your info 12kw is 40k btuh,200 watts lighting flourescent would give you about 1400 btuh which is 42k or 3.5 ton just on that information.
Question #2 as you propose my answer would be undersized under your scenario...However serverroom said aprox 12,000 watts and how was that determined every piece of equipment will not be running at full load simultaneously 24 hrs a day and then you added the other variables. As an alternate scenario I propose the serverroom is in the basement of the same building with the 1st floor area above the server room deep freezer for a meat packing operation. or better yet Profeesor plum in the green room with a candlestick.
#3 which system- your suggested 5 ton or the 3 ton to be installed? As I proposed it 42k if everything ran simultaneously at full load 24hrs a day (which is not reality) it still would depend on an outside temps,whether or not it was day or night, However I will answer this along with your statement:
"Not a one….but, and you know there’s always a but……based upon a design temperature outside of 59 to 90 degrees F, what is the difference of a system in Hollywood, FL or Hollywood, CA?"
There is a tremendous difference especially in latent loads I worked in San Diego for 2 years where you that climate tries to add humidity this climate tries to remove so this contractor by using 3 ton will have a slightly longer runtime thanif he used a 3.5t but reduce the latent humidity load in doing so. In La/ san diego you would not want as long as runtime because you want to remove the heat load as quickly as possible so as not to pull what little humidity that does exist out or as many do have add a swamp cooler system to put humidity into the conditioned space as well. So the answer is a big difference.
And #4: First this disclaimer: Traditionally, the tightness or ventilation of a space has been expressed in air changes per hour. However, many professionals routinely use CFM as the primary unit of measure. Although both units clearly have their uses, CFM is more easily obtained, because it does not require calculations of volume. More importantly, it is a more direct expression of the main variable with which we are concerned. Although ACH includes an adjustment for the size of the building, that consideration may be less important than others and can be taken into account in other ways. If we are interested in estimating heating/cooling cost or sizing a heating/cooling system, we are concerned only with the flow itself, not the flow as it relates to volume.
If we are considering ventilation levels, we can more easily deal with CFM rather than ACH, and are probably more concerned with absolute flow than the flow as compared to volume. If we are dealing with small, heavily occupied spaces (trailers, apartments) or large spaces with few occupants, ACH can be misleading. (ACH can sometimes make a large space look tighter and a small space look leakier.) For these and other reasons, CFM is being used more often, and ACH less.
Now that said :
well first of all what is the ceiling height?
but guessing it is 8 which would leave you with 600 cubic feet of airspace if no one is inside it. And then if there is no door just an open passway to the next room it would really screw things up but I will guess the room has a door that is fairly tight and no windows or ones that dont leak like a siv so I will guess it is a perfectly sealed room and all the duct is in the conditioned space so it will leak into the room if it does and that the ductwork was properly sized. In a perfect world you would have 120 ACH. Your mileage will vary if it is a blower door world.
PS: Optional answer on your part, but was just highly curious regarding your age and experience in the business? I’m 48 years old and have been in the business for 30 years full time.
PSS: Really don’t mean to make you mad, but just want answers to the above questions….really
A) It does not make me mad at worst if you prove me well actually I am pretty stubborm you would have do more than that you would have to convince BEYOND ANY DOUBT I was wrong and if you do besides a bruised ego and a tail between my legs I will have learned something which I am always open too...really.
b) I am 38 with 2 years school where I worked in the trade while I was in school. 5 years working for others, 5years for myself- all residential/light commercial a/c refrigeration all in Florida. 1 year working training techs for a York distributor for the Riviera Maya Mexico based out of Cancun,2 years all commercial work in San Diego, and now I back in NJ for about a year and a half where I am from because my family is here and I got custody of two kids and need the help raising them but I started my own business last April here, but my main income is working for an engineering /architect that does energy star homes certifications and design and won this years energy star partner of the year award I have been design doing mostly load calcs/duct design for homes in Northern New jersey for that company and through working for them I was able to get my own contract doing rebate sizing reviews and inspections for a utility here (although it looks like that gravy train may be taken over by the state in a few months). I also attended a regular college for 2.5 years before I started school for airconditioning. Roughly 17 years I guess education and experience 12 of it in Florida. If you want to prove me wrong beyond a reasonable doubt try asking me heating or ice machines questions. As until San Diego the only heat I was exposed to was electric and ice machines well they just suck........ I have worked on marine and aviation systems as well. In Florida I did a lot of work for Pratt Whitney engineers that were ...well "just being engineers" but I learned how to stand my ground by defending myself against the ideas and theories they came up with on how they where teach me some new innovative way to do airconditioning....the scariest one was a jet engine turbine designer who closed off half his return and drywalled it in and wouldn't believe me the system was not working right because of airflow problems. I had installed it he didn't like the return cause it was too big and on an open living room wall so He "fixed" cause his buddy another engineer said bla blah.. I finally got my sawzall cut the whole back open almost hitting him as he was trying to grab it out of hand cause he didnt want me to do it then I showed him the rise in the suction pressure and he said nothing......I told him the cutting was free but if he wanted me to put the original return back for him it would be $250 as it his changes were not included in the warranty and left. The next spring he called for a maintenance service the return was back and he apologized then he told he can't believe he could not understand it was an airflow problem as that is what he does Turbine design.......I pray before I get on Boeings using pratt whitneys.
Ok learn me now Senor........ I really do like too learn and you can never know it all in this industry, those who think they do.....work as SEARS installers.
thehumid1-------I live in NJ, a state where it's free to come in but you have to pay to leave!
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