Evaporative cooling in Factory

Akshay Pahade
LEED Consultant
May 30, 2014

HVAC

Hello!

Need understanding on the modeling of evaporative cooling for LEED NC in eQuest...

We're working on a textile manufacturing facility which has two major sections - sewing and cutting. these sections are planned to be cooled using evaporative cooling.

Firstly, do such spaces get counted as a conditioned space? If not, is it ok to just add the connected load on a separate energy meter in eQuest and operate it on the schedule as actual. in that case, we'd not be claiming energy savings for evap cooling.

Is there a better way to be able to claim the substantial savings the evap cooling offers?

Answer:

Author

Divya Nambiar

June 3

0 users voted0 users voted

Answer:

Hi Akshay,

The power consumption with evaporative cooler is lesser, as power requirement is limited only to the fan and water pump. As against the closed refrigeration cycle in which a compressor is required which consumes most of the power. These are savings that you can be able to show in an energy model.

However, if you add it on as a connected load in eQuest, you will not be able to model the savings that you have by using the evaporative cooler as you will only be adding the load of ventilation fans and pumps in both baseline as well as the proposed case.

Ideally the factory spaces you mentioned are included in conditioned spaces. As per ASHRAE 90.1, - an enclosed space within a building that is cooled by a cooling system whose sensible output capacity exceeds 5 Btu/h·ft2 of floor area is a conditioned cool space I also assume that majority of areas of the project would be factory served with evaporative cooling. Modeling as conditioned space will enable you to show substantial savings of the proposed case form the baseline case. If you model them as conditioned space you will need to add the humidity control as well.

Evaporative cooling does not usually have the full cooling capacity, so, you may need to adjust the set-point in spaces served by the evaporative cooler. The cooling schedule of the baseline model also needs to reflect the same. Even though you do not have mechanical cooling, you would need to simulate it using a very small value for capacity and use the evaporative cooling as an add-on feature as available in eQuest to take care of the unmet hours. Modeling with 0 sets it as auto sizing, so you can model the using a small number like 0.01.

The eQuest user manual if searched by the keyword, evaporative cooling, should give all the information you need to model this.