We are trying to pursue enhanced refrigerant management credit for our project which is a manufacturing facility. There are some R410a air condition systems for the office, but majority of the cooling is accomplished through DEC.
The air condition don't meet the requirement for either path for this credit, but we are trying to factor in water as a refrigerant for the DEC system, to achieve through option 2 of the credit. However, the calculation asks for BTU but we don't know how to conver the DEC into a capacity in units of BTU... does anyone have any experience with this?
Jean Marais
b.i.g. Bechtold DesignBuilder Expert832 thumbs up
November 20, 2020 - 5:06 am
Firstly, water in a DEC system is not a refrigerant in the sense of the word, because there no vapour compression cycle. I would make the case that you are using a cooling equipment with zero refrigerant. So just enter it into the normal calculator with ODP and GWP of zero. The DEC System must have a manufacturer rated cooling capacity, but your problem will be that the rated capacity test proceedure will be vastly different than that of a chiller. I would use the design cooling capacity needed for the space served by the DEC, because an equivalent chiller will be specified to meet the same design capacity. If you include a narrative explaining all your methods and calculations, I would think you have a chance.
On the other hand, using a DEC system, it could be considered as a load reducing stradegy like using exterior blinds. Those don't use any water either, right? But I don't get credit for those. The LEEDv4 credit uses a specific GWP calculation meaning the amount of cooling power in the project is irrelevant. It only tests that the used refirgerant is good per kg of refrigerant used.
This is just a downfall of the credit. It doesn't measure the absolute damage done, just the damage done per kg of refrigerant used. They could have normalized it against the Project m² cooled space. Well, no one's perfect.