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Sweat and body heat

How do you figure out how many BTU's are produced by the human body ,pedaling their dupa off on a stationary bike ,for 45 min. So far, I've been told that upto 2 liters of sweat can be produced by the pedalist.How do you convert that into BTU's.  Is this related to 970BTU per lb. of water?This  KindaSorta relates to the previous thread on  evap/cond coil & under/over sizing.There are 45+ bodies doing this all at the same time in the same room!


  • meplumbermeplumber Member Posts: 678
    Gotta dig out an old plan.

    Techman, I did the HVAC in a fitness center a few years ago. I will see if I still have that information in the archives (pile of s**t in the back of the shop).

    I seem to remember an ASHRAE number of like 950 BTU/h/person in exercise rooms. But don't quote me on that. I don't remember the humidity increase, but it was on the specs.

    Maybe I can find it in the morning.
  • don_9don_9 Member Posts: 395
    Sensible n latent load

    Hi Techman.We treat humidity in the winter with dry fresh air and in the summer with the cooling equipment.

    Most time the load is base on how many cfm of fresh air you would need per person plus their activity.So with a good commericial load program you could plug the numbers in and get your cooling load.

    i guess what i an trying to say is that during the summer if the cooling equipment was design with so many people in mind that you should not have a issue with humidity being the your load for people and fresh air is going to keep the humidity in check during the summer.

    The winter time is a different story bc the heating equipment is turn off so that means no dry fresh air is coming in and you get window,mirror and floor sweating.

    Hobo data logger to monitor co2 and humidity over time and you can get it in check with the right tstat.

    Are you dealing with a building that was design for the envelope only and not all the people it is seeing now?
  • TechmanTechman Member Posts: 2,144
    edited June 2012
    Sweat & heat

    There is zero fresh air introduced into the bldg. There is zero design spec's . The room temp is set for 62*,to try to stay ahead of the inrush of bodies.For years the evap coils would frost over and then no cooling,and then they manually shut off the comp to thaw the evaps.And so on.We installed special freezestats to allow the evaps to frost over a little ,with evap temps of 25*-22* there will be frost.The two AC's equal 9t,but the actual tonnage is more like 7.5t due to the  lower operating evap temp ,the AC units are now in good running condition. So my next step is to check BTU's available vs. BTU's provided by the sweat and the  heat of all those pedalist's.
  • don_9don_9 Member Posts: 395
    fresh air

    No fresh air,wow I could only assume that your co2 must be very high.Not to mention humidity level being high with driving the temp down to 62 and all those bikers.

    If you were to pipe some fresh air into that building you could increse the run time and efficency of that equipment and put the building into a positive pressure that would help block some of that infiltration.

    If I knew the size of the room and peak load I could get you some idea of the btus for that many people at work.

    It is a wonder people are not complaining about smells and their health in that building.i see a chance to make some money there.Then maybe not depending on the owner and how much they care about IAQ.
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