Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
These were intentionally left blank (by me). You would have to look in the engineering specifications for the VRF unit in question. The change in heating capacity for a change in piping height or length is probably negligible and therefore there is no need to account for this and this input can be left blank (or you could enter 1 as is defaulted). You can look at Figure 12 in this document to see an example for the change in cooling performance with different pipe length and height. Notice the near vertical lines as piping length increases (sorry for the blurry picture). The fractional change in cooling performance is 1.0 at 25 m (e.g., actual Qcool = Qcap/1.0). This fraction decreases as piping length increases (to about 0.8 at ~435 m). The heating piping loss charts that I have seen do not have these vertical lines, meaning there is no change in heating capacity with changing pipe length/height.
