Mechanical Design Issues - Heating Energy

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So with degree days we have heating degree days and cooling degree days, and the way that we start to think about this is we have a baseline which is 65 degrees, so we have a 65 degree baseline, and then we're trying to figure out how much time, over the span of a year, is this particular location, just on the averages, the way that information has been built up over time, we have a whole series of meteorological books available to us to figure this stuff out, so on average, across the span of the year, how much time is it less than 65 degrees, and how much time is it more than 65 degrees, so from a heating degree day, if it's above 65 degrees for any amount of time, well then that amount of time registers as zero, because we don't get any benefit for the fact that it's above that, we're just looking for how big our heating system's gonna be, and how much energy it's gonna take to have the heating system on, we don't get free money back just because it was warm enough that we didn't have to have our heating system on, so if it's above 65, that's just a zero, just zeroes out in the calculation, if it's below 65, then what we're doing is we're taking the high and the low, and we're averaging them, so we have an average temperature across the span of the day, and then we're comparing that average temperature to the 65, and if it's below, we can subtract that number from the 65 and it'll give us an idea of how much below that day is than our basic 65 number, which is gonna give us a little bit of leeway, the building's sort of assumed to be okay if it gets a little cooler than our target number, but if it gets a lot cooler, we have to start adding that heating, so that's how we're figuring out how much heating across the year we have to put in. So remember, the times when it's above the 65 doesn't count, but all the times when that average is below the 65 and it will tell us the total number of degree days, heating degree days that we have to add to in order, across the span of a year, because that's a really important question for us, because we really wanna know how much the energy's gonna cost, and how big of system this is across the whole span of time, so that's a clear understanding of what we're trying to get to, it's important to know what the worst case scenario is, because we have to be able to meet that, but we also wanna have an understanding how much money this is really gonna cost in order to run this building through the year, so heating degree days, exactly the same thing with cooling, we still use 65, we just average it, and then it goes the other direction, and obviously if it's below 65, we just count it as zero, in the same way that if it was above 65 in heating degree day, we counted it as zero. So this is just a way of understanding the heat loss across the span of a year so we can really understand the scale of how much energy and money it's gonna take to keep this building heated through that year.

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