ASHRAE Conditions for Global Warming

[nuuvox000]

Has ASHRAE come out with any guidelines or standards design conditions that take global warming into account? I couldn't really find anything doing a search online but I'm thinking I need to start taking my load calcs up a couple of degrees at least to account for the annual record-breaking heat we're getting where I design. Would be nice to have some scientific guidelines on how much I should account for though.

Have any of you adjusted your calcs for this?

 

[EnergyProfessional]

Isn't this just Bill Gate's conspiracy to sell more vaccines for 5G cell towers causing cancer

Most their stuff looks like it is from the 1970's...... So I wouldn't count on them. And when you see their previous (new ) HQ (huge glazing!) and the fact it is being torn down now, they seem to be causing more global warming than actually wanting to do something about it.

In my case the ASHRAE values don't even meet local code. So for design (to me) it is pretty much useless anyway since I need to meet code.

You raise a very good point and I wondered that myself. Next time I design a cooling application I'll ask my JHA if I can use higher ambient conditions. You don't only add load, you also degrade equipment performance. But you want to have some scientific backing to see how drybulb and wetbulb temperature will be impacted.

 

[nuuvox000]

I don't know where you design, but where I am, the local JHA's have no clue about engineering. Half the time they don't even know code that well, so unfortunately they wont be much help for me.
Yes, I would like scientific backing for sure, I realize that I'm only an engineer. Get to work, scientists!

 

[EnergyProfessional]

Have you asked JHA about this specifically. Or do you just assume?

 

[nuuvox000]

I'm just assuming about this specific question.

 

[EnergyProfessional]

I hope no one makes assumptions about your knowledge before even asking you.

We don't even know if you are in Saudi Arabia, or Alaska.......

 

[nuuvox000]

Well, someone could certainly make a pretty accurate assumption if they've worked with me for a few years; but point taken.

 

[EnergyProfessional]

FWIW, you made me curious and I contacted our JHA. Our energy code lists 87°F DB and 75°F WB as ambient design temperature. Larger equipment typically means less efficiency. So I assumed those are maximum design temperature to avoid oversizing.

But they stated I can use higher temperatures and this can be done if the owner wants to have the higher building comfort on warmer days despite higher energy use.

This was a bit surprising to me. I had asked them a similar question about interior design temperature a while ago and there they stated this is done to ensure a designer doesn't achieve energy savings by just choosing weaker design conditions. I assume this is similar here. Basically every designer is forced to achieve the required efficiency while maintaining a minimum level of comfort.

So before creating your own standards and design conditions, read your code and ask the JHA what your allowable design conditions are. Then use science and judgment based on that while meeting code.

Now I'm not sure what ambient temperatures I will use for the next cooling design. I probably will pick some of the ASHRAE percentiles that are a few °F above what our code requires.