Comparison of Transfer Function & RTS Method

[walz]

Has any one done a comparison of Cooling load calculations between transfer function and RTS method.

I am trying to make this comparison these days for an identical building doing twice by each method.

if anyone has done this before, please share the experience. which one is more accurate or whats the difference in two.

 

[MintJulep]

There was a bunch of ASHRAE research done before RTS was introduced in the ASHRAE Handbook and Load Calculation Manual.

I suspect that a little poking around on the ASHRAE web site would turn it up.

 

[walz]

I have several literature for ashrae and for other stuff too... which talk about these different methods....

my question was about somebody would have actually done it in real .... and to share what did they find in this comparison...

We do our load calculations with HAP ... which is based on transfer function .... We are familiar with HAP and to much extent we do understand what this is doing...

Our company is switching to Revit MEP 2011, and we need to do the load calcs using Revit ... which is RTS Method.

this is going to be an interesting excercise ... i was curious to know and share if somebody else has gone thru the similar exercise.

 

[ChrisConley]

We're going through the exact same exercise. For a while it's going to mean two sets of load calcs until we catch on.

I've heard that the difference is relatively slight between the two methods, but that RTS is more accurate.

 

[walz]

Hey Chris

Im just curious to know ...

Are you going to compare HAP result with Revit MEP
... if yes then i'll wait for your results....

I have done a sample test load in both HAP and Revit ... the difference was just 2% which is exciting ... revit was 2% higher than HAP.... and now iam going to do the same for an actual project ....

 

[ChrisConley]

We are doing a comparison, I'll post results when we get them.

I'm expecting the largest change to be with regards to shading geometries and daylighting.