GEED is a Building Energy Modeling FAQ
Following are the FAQ which might help you resolving queries of your clients in day to day meetings
Q1: Why we need energy modeling? Is it necessary for LEED certification, especially in Dubai?
Answer: Energy modeling is a mandatory analysis for any building aspiring for LEED certification. In Dubai. The code is some how more stringent then even in US. Here for getting certification only, you have to show a saving of 22% or more over the ASHRAE 90.1,2004 base case. While in US or in India it is need dependent. This means that, if I can’t gather credits in other available sections. I will try to fill the gap by Energy modeling credits. In Dubai it is mandatory from regulatory bodies to have at least 22% saving which corresponds to 4 credits.
Q2: How much time it would take to complete the energy modeling for a building?
Answer: As stated above in the introductory part, the energy modeling is a very comprehensive and informed and structured data entry process in modeling software. It requires knowledge of programming, thermal engineering, building system and other building dynamics to create an acceptable model. The time required depends on the size of project and also the complexity associated with geometry replication for thermal model. So eventually the software can understands it rightly. It can take 20 days to 50 days.
Q3: What do you need from us as an MEP consultant?
Answer: MEP consultants are going to play an important part in the proposed model development building process. They are going to tell us about the kind of cooling system they are planning to propose as early as possible. Some time it is impossible to have air cooled chilled water system in the building. Now if these things are not discussed before hands and get in our notice at the time when the orders are placed, this can lead to very difficult situations. So MEP consultants are going to help us understand all the MEP drawings and the entire philosophy behind the design.
Q4: What do you need from us as an Architect?
Answer: The architects are going to help us create the thermal model of the building. They will provide us the drawings and documentations for the subject building. Basically the involvement of architects is seen in the modeling process for envelop optimization for reducing solar gains and improving the day light efficacy of the building. Architects with our help can recommend best glazing to the project. Where in the team have to justify the aesthetics with energy efficiency. We can also recommend some changes in envelop system like adding shading devices or improving insulation etc. Architects are going to decides over the cost benefit or energy vs. aesthetic of what ever we propose. It is going to be a highly interactive process.
Q5: What are the deliverables of Energy modeling company?
Answer: The Energy modeling company would be working in with architects, MEP consultants and LEED AP for developing a best and most cost effective package of energy efficiency measure for the project. The proposed energy efficiency measure could be recommended by a LEEP AP, architects and MEP consultants as well, apart from the energy modeling consultant who is going to work out all possible EEM form his own experience.
Once the Proposed packaged of energy efficiency measures is agreed by all the responsible parties, which includes Architects, MEP consultants and very importantly the Owner, The energy Modeling Company would give off a report detailing all the Energy efficiency measure for the building. There corresponding thermal properties and other specification as required by the tenders.
Q6: What is the involvement of owner in the entire design process?
Answer: The owner should preferably frame certain policies about the kind of vision, he has. The LEED AP need to get the insight of what the owner actually wants. Whether he is just looking for certification or he is putting it up as a prestige project for showcasing his CSR and to look different in crowd. Both the cases are possible. Incase he is just seeking a certification, an early and conscious design does not require more then 5% cost on greening process and its implementation. So we will repeat an early design and proper communication of policies set forth by the owner and the developer, which will save 80% of the headache of the green design and implementation.
Q7: What are those parameter, which needs extensive care in the green building design process early in the design stage?
Answer: Chiller selection, glazing selection and day light design. A better chiller would alone save 10% to 15 % of energy, where as the day lighting can save up to 8 % if properly designed. Glazing on the other hand is responsible for about 5% to 10% of saving. Insulation on brick, VFD in plant, demand based ventilation, cooling tower and pumping efficiency measure can brings in a saving of the range of about 2% to 4 %. So if we plan few things in start about the major energy guzzler we will keep our self on the safe side for the rest of the design process. For example an extra capital required in a better chiller, better glazing etc can offset its payback in not more than two year.
Q8: What does The ASHRAE 90.1 2004 says about buildings?
Answer: ASHRAE 90.1 2004, for a large building says that you have to use a 6.1 COP chiller in the base case. In practices in Dubai region people use air cooled machine, which are not even compliant with ASHRAE 90.1,2004. So it has to be cleared on the day one that they might have to take decision that they haven’t taken before. This is quite prevalent problem in Dubai region, which we face in our day to day interaction. So making it clear from day one is better.
Similarly for example Lighting in office area for the base case is about 1 watt/Square feet. This is too stringent for an armature MEP consultant. Who never work for a lighting system below 2 watts/Sq.ft. The point we are trying to communicate is that if some one thinks that 0.8 watts / square feet is not possible then he cant work on a green building project. Because we are going to have some neck to neck saving from lighting system by putting our Light power density to a level of 0.8 watt/sq.ft
Also ASHRAE is quite stringent in glazing as well. Every façade of the building facing different orientation have to use different set of shading coefficient (SC), U- values and Visual Light Transmittance (VLT) in the base case. Now to get saving over that, we need to squeeze every bit of what is available.
ASHRAE 90.1.2004 also says about the kind of envelop, insulation and Air handling system etc. which all are significantly stringent. People ordinarily never achieve even 25% of ASHRAE 90.1,2004 in that part of the world. Simply they are not use to such kind of closed and informed design at all. Now the point a LEED AP should understand that there are going to be hundreds of clashes in the design process.
A conscious LEED AP should always maintain an upper hand in the design meetings. And makes sure that he communicates the entire possible situation and get an answer from the owner or responsible person instantly.
Q9: What is Energy Efficiency Measure (EEM)?
Answer: Once the base line building is done which uses that values depicted in ASHRAE 90.1,2004 Appendix G. The proposed Building is made from architects philosophy and MEP design recommendations. Very rarely the annual energy consumption of this proposed design matches with the ASHRAE Baseline design. So to get LEED credits we have to show saving over ASHRAE Baseline design. Now for achieving this we come to individual EEM and model them in our proposed building model and compare with ASHRAE Base line design. We keep on adding EEM and try to achieve the target saving which is 22% for certification jobs in Dubai, iteratively.
Achieving even this 22% saving can become a difficult task, if the points highlighted in Question 7 about early design consideration are not considered in time.
Q10: what records a LEED AP has to maintain about the energy model?
Answer: A LEED AP has to be conversant from energy modeling terms. He has to maintain all-round records of the EEM and corresponding saving which is achieved from application of those EEM in various version of simulation process in different iterations. Energy modeling consultant would help them out for compiling such data.
Q11: What are the various techniques for suggesting a right product for the client effectively?
Answer: A small financial analysis depicting Pay back or Net Present Worth of the various options is a good strategy for convincing clients and guides them to take right decisions quickly and effectively. The process of doing financial analysis requires some rough estimate capital cost of the project EEM or Options and their simulation dependent variable. Like for Glass we need U-value, SC, and VLT, for Chillers you need COP @ARI conditions, for insulation you need U-Value and Specific Heat Capacity, and for paints and Cladding you might need the emissivity or some coefficients for reflectivity etc.
A right financial analysis is some thing very important for the owner or developer for understanding the worth of that particular decision.
Q12: We want to start Energy modeling right now, what we should do?
Answer: You have to give us the Plans for building and section details as well to create an approximate thermal envelop the plan should contain the direction of building with respect to true north. You have to tell us where is this building located i.e. latitude and longitudes; also you have to give us a kind of area statements, where we can have an idea of which space in the building is utilized as what. The HVAC details should contain the preliminary zoning and system identification. This would help us create Air handing system for each zone as required. We might also need proposed plant details. Such that design parameters of plant are clearly visible.
Apart from this we might need the architectural philosophy document, Heat load sheets etc. for calibrating our model.
You will get the energy modeling report with in the month after providing this data; also there will be lots of possible interaction in between for understanding the system and drawings.
Q13: How many credits we can get from Energy modeling?
Answer: Theoretical total of 10 credits can be achieved from energy modeling only, but this rarely happens until unless it is a prototype test building. In practical situation with all the difficulties we can achieve at least 5 credits which correspond to 26% saving over ASHRAE base case. But if the Developer is committed for more credits we can work out a procedure where we will squeeze every possible measure to achieve 7 to 8 credits provided that the developer has no limitation on energy efficiency purchase and spending.
Q14: As an MEP person or Architects what would I get from Energy modeling Reports?
Answer: The energy modeling report would help you in selecting the right building product that eventually you have to use in your building as a part of some proposed Energy Efficiency Measure EEM. The energy modeling report would contain only the thermo physical or mechanical product specification which a tender requires for attracting quotes.
Q15: What do you suggest, should we go for energy modeling credits or we should focus on the other credit available on LEED NC 2.2 book?
Answer: If you are in US or any other part of the world you can strike a balance between cost and individual credits. But in Dubai, as a part of the ruling regarding green building you have to have at least 22% ( or 4 credits )saving from simulation only. There is no give away to that.
Q16: What set of LEED credits are most economically active, and what are passive credits?
Answer: Any credit, which you endorse and it gives you recurring saving in you annual electricity bill is an economically active credits. Energy modeling deals only with such credits. These credits would let you realize a breakeven in coming days. Also they would assist you get return on investments overtime. Where as if you talk about a credit, which does not have any repercussions on energy usage, like parking for electric vehicles etc. and given off a charging point in the parking lots etc are passive in nature and generally not assist in any immediate return. So you should look at such cheap credits early in the design.
Q17: What should be the team Structure for LEED projects?
Answer: LEED projects are some how a new concept, and need a different level of team integration and communication between the stake holders. Briefly the team consists mainly of Architects, LEED AP, Energy Modeling Consultants, MEP consultants, Vendor development specialist and developer/Owner etc.
Q18: What kinds of software are used in Energy Modeling?
Answer: Visual DOE 1.4, DOE 2.2, Energy Plus and few Excel templates for Saving calculation and financial analysis are used in integration to get effective results.
Q19: How the base case energy model built for my building?
Answer: You just have to provide us the architectural plans, zoning details, system details and plant details. Also preferably a 3D building drawing in AutoCAD *.dwg format for understanding the envelop correctly.
Then we will use the Appendix G of ASHRAE 90.1,2004 for selecting the recommended baseline material values for your building. After gathering these values, we will make a thermal model for your building and input all the selected parameter in the simulation software.
Q20: Is presence of energy modeler necessary in all LEED meeting?
Answer: No, Energy modeling person is only required for communicating the needs of any system which he proposes for EA Credits. Hence, if present then it would be good any way. The results energy modeling is very clear and comprehensive in the form of spread sheets or reports, which depicts the saving associate with each EEM. The LEED AP is capable to communicate the saving and other financial figures himself incase Energy modeling person is not available.
