Very Interesting Discovery

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I was working on an old model I last simulated in 2011.? I had 220 unmet heating hours, no unmet cooling hours and a total utility cost of $137,742 with a TMY2 file for Hartford CT.
I changed the weather file to TMY3 Hartford Bradley International Airport and the unmet heating hours dropped to 44, no unmet cooling hours and a total utility cost of $137,301.
To make it more interesting, I changed the simulation year to 2016 and the unmet heating hours climbed up to 88, no unmet cooling and a total utility cost of $249,081. Changed it to 2017, the unmet hours stayed the same and the cost increased slightly to $249,190.? The annual energy escalation rate is at the 5% default.
Any ideas?

Paul Diglio87 Fairmont Avenue
New Haven, CT 06513

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Joined: 2016-07-15
Reputation: 400

Simple, I believe, Paul.
I believe TMY2 is based on years 1961-1990. TMY3 is based on more recent years.
Also, changing the year changes the dates of Sunday through Saturday. Thus, if you building either shuts down or has reduced operations on the weekends, you are moving the temperature profiles to different days.
Logical?
Did i actually beat Nick Caton to this one?
John R. Aulbach, PE
On Friday, April 14, 2017, 9:43:13 AM PDT, Paul Diglio via Equest-users wrote:I was working on an old model I last simulated in 2011.? I had 220 unmet heating hours, no unmet cooling hours and a total utility cost of $137,742 with a TMY2 file for Hartford CT.
I changed the weather file to TMY3 Hartford Bradley International Airport and the unmet heating hours dropped to 44, no unmet cooling hours and a total utility cost of $137,301.
To make it more interesting, I changed the simulation year to 2016 and the unmet heating hours climbed up to 88, no unmet cooling and a total utility cost of $249,081. Changed it to 2017, the unmet hours stayed the same and the cost increased slightly to $249,190.? The annual energy escalation rate is at the 5% default.
Any ideas?

Paul Diglio87 Fairmont Avenue
New Haven, CT 06513

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Joined: 2016-07-15
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