2014-09-08 17:00 GMT+02:00 Ayzer Akguc alpayakguc@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx>:
ÂHi Jean,Thank you for your answers and suggestion for  LEEDuser.comThe guide I mentioned is about district energy source modelling prepared by USGBC. I sent this guide to you in an attach file.ÂThe requirements in this guide also exist in LEED Reference Guide for Building Design and Construction v.4 (page 363 - 373). However, Option 2 is represented as Path 2 in Option 1 in v.4.You mentioned about modelling propose systems as designed. In project, CHP systems work with backup HVAC systems. However, I need to model HVAC systems without CHP according to Option 2. The calculations of CHP is carried out according to a calculation methodology (as an external calculation) described in guide. Besides, it is mentioned about modelling absorption chiller for proposed case if there is a system as an absorption chiller converts heating energy to chilled water in project. And yes, absorption chillers exist in project that use exhaust gas thermal energy of CHP systems. Therefore, district heating source of absorption chillers is exhaust gas thermal energy, isn't it ? If so, how can I model absorption chiller for propose building because there aren't any CHP systems in my energy model. The main problem of mine is this question.By the way, I realized that absorption chiller is modelled for baseline building if you select Option 1 (Path 1) according to v.4. However, there isn't any notice about option selection for this case in guide I mentioned. Therefore, should I consider this case according to v.4 ?Kind regards,Alpay AkgucOn Sunday, September 7, 2014 1:32 PM, "'jeannieboef@xxxxxxxxx' jeannieboef@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
ÂThere is a very good forum on EAp2 for LEED NC v3 on LEEDuser.com. It is a better forum for LEED based questions.I've not looked at the guidelines you mentioned for quite some time.Â1) model the proposed systems as designed. In your case the district heating source is "inside" the project and you know the efficiencies of the systems and model them as they are.Where you are getting confused is about the language for if you where truely supplied by an external provider from "outside" the project and then the provider won't tell you his efficiencies. This is not your case, as I understand it.2) model also the proposed backup systems as designed.3) baseline system is modeled based on the heating source and building type. What is your main heating source for a CHP trigen? Well you use fossilfuel to produce both heat and electricity. I would say the answere is fossil fuel. So model a gas boiler and use the same gas rates as you use in the proposed...right?ÂWithout looking through the guidelines, that would be my guess.Mit freundlichen GrüÃ?en- Sent from my iPhone (excuse the brevity)i. A.Jean Maraisb.i.g. bechtoldTel.  +49 30 6706662-23
On 05.09.2014, at 15:34, "Ayzer Akguc alpayakguc@xxxxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:ÂHi,I am working on a LEED project. The generation systems exist for conditioning the building. These are trigeneration (CHP) systems each with a capacity of 2020 kW that are used through the year. In heating seasons, the building is conditioned using the jacket water of these systems. In cooling seasons, the exhaust gas thermal energy is utilized using absorption chillers. These systems produce electricity through the year in order to support building electricity demand. By the way, there is another plant group includes boilers, chillers and cooling towers as backup HVAC systems that are used during periods of increased heating and cooling demands.For modelling of these systems, I utilize the â??Treatment of District or Campus Thermal Energy in LEED V2 and LEED 2009 ? Dessign & Constructionâ?? guide. However, I am confused about some requirements in this guide. I selected â??Option 2â?? for modelling these systems. In Option 2, a virtual plant with average capacities is constructed for proposed building if necessary plant data is not available. Â However, I have data of all backup systems and their efficiencies are higher than default efficiencies of virtual plant. Therefore, I modelled these backup systems instead of a virtual plant. Besides, I can compute the electric output and fuel input of CHP systems according to Appendix D in a guide. Finally, I can ensure all requirements until the end of Appendix D.However, I am really confused about â??Heating converted to cooling as part of the LEED Projectâ?? section in Appendix E. In project, absorption chillers utilize from exhaust gas thermal energy of CHP system and convert this energy to chilled water for cooling a building as described in this section. Therefore, I need to model district heating source and absorption chiller for baseline building according to requirements described in first and second step of this section. I am really confused about these steps about how can I model district heating source. If I select Option 1, I need to model purchased heating. It is very clear. However, it is mentioned about â??code-compliantâ?? as described below:For Option 2 ? Aggregate Building/DES Scenario: use a virtual upstream DES plant for the Proposed Case and compare it to code-compliant on-site equipment for the Baseline Case as described above in Section 2.4.ÂCould you please give me an idea about what is â??code-compliantâ?? and how can I model district heating source of Baseline Building according to these sections?By the way, it is mentioned about modelling absorption chiller for proposed building based on the as-design type in fourth step. I think it is more complicated than first step and second step. Why I need to model an absorption chiller for proposed building? How can I ensure heating source of this absorption chiller? In project, heating source of absorption chiller is CHP system and it is mentioned about modelling absorption chillers based on the as-design type. Therefore, do I need to model CHP system for creating heating source? If so, it is not sensible because I select Option 1 if I would like to model CHP system.Could you help me about my problems described above?Kind regardsAlpay Akguc
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Posted by: Jean Marais <jeannieboef@xxxxxxxxx>
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