We are working on a LEED NC 2009 project with DES which the thermal plants consist except boilers and electric chillers also a cogenerator and an absorption chiller.
We are thinking to follow Option 2 of DES v2 guidance and have 2 questions as follows:
1. For the average efficiency calculation, should we deal with the CHP and absorption chiller separately and to model a virtual CHP and an absorption chiller in proposed case or to involve the CHP in the total heating system and the absorption chiller in the cooling system and apply the efficiencies separately to the air-cooled chiller and forced draft boiler in virtual DES model in proposed case?
2. In the DES v2 guidance Appendix E: Heating converted to cooling as part of the LEED project there was written:
‘‘Generally, district or campus systems that produce heating energy (steam or hot water, whether directly or as waste heat) serve heating end use applications in the connected buildings. Sometimes the heating energy supply is converted to chilled water using absorption chillers or other similar technologies in order to serve cooling loads instead. In this circumstance the equipment that converts heating to cooling may reside either within the DES itself (i.e., DES provides cooling to building) or within the connected buildings (i.e., DES provides heating to building; building converts heating to cooling).
When the equipment converting DES-supplied heat into cooling is part of the LEED project’s scope of work, then the DES guidance in this document must be modified for the EAp2/c1 energy modeling path. The modifications for this situation are as follows; guidance for all other LEED credits remains unchanged:’’
The question refers to the first sentence in the second paragraph: We treat the absorption chiller as upstream equipment outside the project’s boundary. Does that mean ‘‘part of the LEED project’s scope of work’’?
Thank you very much!