Heat Loss calc outdoor temp?

Patchogue Phil_29

Anyone know the outdoor temp to use in Hydronic Explorer, for Long Island NY south shore?

Or know of an online source for that information?

Brad White_9

Try this

Islip-MacArthur, more or less the center of Long Island. Data is from the USAF and is in the public domain.

Patchogue Phil_29

differing values

Thanks for the info.

For the outside design temp I am not sure if I should be using the 99.0% Occurrence of 14* or the Median of Extreme Lows of 3* ?

While looking for the info I came across heatload.com website, which stated to use a outdoor temp of 13* F for NYC area.

So, I be confused now.

Brad White_129

Be Not Confused.....

Your local (state) energy code may dictate. From the heating engineer's perspective, we use the 99.6% column. In Boston this is 7 degrees even though we well know it goes down to zero and below every few years...

What I would do is calculate it each way (simple- divide heat loss by one of the Delta-T's and re-multiply by the other). See if and how much that changes your boiler selection...chances are the differences are slight and the increments of available boiler capacity will cover both with the same boiler...

Let me see if I cannot rustle up the two NYC Airport data documents... Be back soon.

Brad

EDIT- JFK and LaGuardia Data attached...

SO.... The 99.0, 99.6 and Median of extreme lows respectively are:

Islip 14/9/3

JFK 16/12/7

LaGuardia 16/11/6

Which best represents your experience? And which makes a difference in your calculations?

Patchogue Phil_29

Thanks

Thanks again for all the info. Greatly appreciated.

I live maybe 10 miles south-east of Islip/MacArthur airport, so I will use the numbers from that chart.

I am curious what column other people use for their heat loss calculations?