CIBSE BSG & CIBSE HVAC Colaboration Event 2019

CIBSE BSG Vice Chair Darren Coppins collaborated with the CIBSE HVAC Group to provide a joint CIBSE Building Simulation Group and CIBSE HVAC Group event at Hoare Lea on the 18th July.  Darren discusses the event below:

 

I was privileged to be given the opportunity to present a piece on HVAC Simulation at a joint CIBSE HVAC and BSG Group event alongside Robert Cohen of Verco and Ant Wilson MBE of AECOM.

Ant Wilson was first to present, providing views on the risks associated with advanced modelling, suggesting there isn’t enough data to accurately model buildings.  With advanced modelling, you have a chance of getting it right, but you also have a chance of getting it even more wrong considering the assumption that is necessary to make during the early stages.  Couple this to weather data that may be flawed and variable competencies and you might be better off using an Excel spreadsheet than building simulation.  I should highlight that those were not Ant’s exact words, more my perhaps slightly exaggerated interpretation.

Robert Cohen of Verco was up next, discussing the improvements Australia has achieved in its building stock over the last 2 decades of the NABERS Scheme.  For those not in the know, NABERS is an in-use rating scheme that has been running in Australia for some time.  Based on the in-use rating of buildings, it measures the real performance of the landlord services and drives the reduction of that energy.  When designing a building that will target a NABERS rating, advanced building simulation is required to demonstrate that the buildings are actually capable of achieving that target.  The model and mechanical design are then independently scrutinised.  This has lead, not only to the reduction in building energy use in Australia, but also the upskilling of the modelling professionals and improvements in mechanical design to deliver better systems.

Robert then handed over to me to discuss advanced modelling in the UK and why we should do it, but also how we don’t do it.  The majority of us modellers have developed very good skills in modelling for regulatory compliance or overheating, but when challenged with detailing a full HVAC system and its controls, ultimately we fall very short of the combined skills needed to correctly configure the model.  As Ant mentioned in his session, if we undertake more advanced modelling, then there are more variables to get wrong and more chance the results will be even further from reality.

We also have another barrier to being able to accurately model buildings, which relate to limitations within the software itself.  There are aspects of complex thermal responses happening in buildings which we usually ignore, like stratification or local radiant impacts. Thermal bridging is usually also ignored in respect of how that actually impacts on the zone it is within.  It is for this reason that I believe that the modelling community need to step up to the greater challenges that more advanced modelling presents with an open mind to develop their own skills and hold some scepticism in interpreting the results.  In an ideal world, modellers will develop the skills to be able to interpret the results and provide an assessment of how likely a building is to achieve those results, in full knowledge of the software’s ability to accurately model the building in question AND the quality of information that has been provided to model it.

For anyone wishing to pursue full HVAC systems simulation, my advice would be:

• Try it out with a simple building first with simplistic controls and then spend some time reviewing the results in detail at a time step level.   Even better if this can be an existing building from which some good energy data exists.  Experiment with changing control strategies and see what happens;
• Do not get drawn into applying software templates for HVAC systems without fully understanding what each physical and control item within it does and how it works.  The main software providers have good technical documentation on these, but reference to CIBSE Guide H (Controls) CIBSE AM11 and a good understanding of HVAC systems is essential;
• Understand metering of systems and how the energy flowing into an item of plant may be different from the energy flowing out, where the meters are placed and why.  CIBSE TM39 is a good resource for some additional information on metering strategies;
• If you are not a mechanical engineer, find one experienced in detailed design of HVAC systems and go through your model and controls with them;
• Don’t underestimate how long it will take to set-up a correctly detailed model;

I’d like to thank CIBSE HVAC Group for leading and organising this fantastic joint HVAC and BSG group event and everyone who came along, for attending.

Technical Presentation 12 June 2019

Attendees of the CIBSE Building Simulation Group 2019 Annual General Meeting had the chance to sit through the technical presentations of the group's chairman Darren Woolf followed by a lively discussion. 

The first presentation 'How flow can you go' drew from Darren Woolf's talk at The Future Envelope 12, Building Envelope Conference. 

Five case- studies were presented on:

• Wind pressure simulation 
• Pressure loss calculations (effective areas & discharge coefficients) and resulting flows
• Heat flow through complex glazing systems
• Glass temperatures impact on room air flow
• Multiple phases of heat transfer and condensation risk

Challenges very often presented to dynamic thermal modellers when modelling for natural ventilation were presented and links to CFD studies especially relevant to designing for performance.

The second presentation focused on ground heat transfer, the limitations and potential misalignment of ground heat transfer/U-value calculations and dynamic thermal models. Comparisons of the heating energy predicted by DTM and a co-heating test for a case study were also presented and discussed later on.

Click below to see the presentation.

Building Performance Modelling at this years CIBSE Technical Symposium

CIBSE BSG's Vice Chair Darren Coppins discusses his perspective of the CIBSE Technical Symposium in Sheffield which was held on 25th & 26th April 2019.

As a long term attendee of the CIBSE Technical Symposium, I look forward to getting away for a few days to listen to technical papers presented by the very enthusiastic and bright minds who make up our community.  This years event was held in the rather nicely equipped Diamond building of Sheffield University.

The Diamond Building - Sheffield University (Image from Sheffield University Website)

It is an event where the technically minded get together to talk much the same language.  There's little in the way of sales and products but much in the way of debate, opinion and fact.  With 3 parallel sessions, there has always been something to whet the appetite.  The papers and presentations that go with each session are also available for delegates to download to review at their leisure.  For me this is great, as you can have the paper or presentation in front of you as you are listening to the speaker.  Papers of past symposiums can be downloaded here.

CIBSE Technical Symposium Chair Prof Tim Dwyer addressing delegates on Thursday Morning.

Building Simulation is normally a popular topic but this year it appeared in some form in almost every session I attended.  For the first time there were some suggestions that software limitations could impact the results to the extent that more simplistic hand calculations have as much chance in predicting actual building performance as advanced simulation.  These were more opinion papers or opinions of the delegates than anything based on study or fact, however, it brings to light that the more advanced modelling we do, the more we will find limitations in the software we use.

In my view, this is a good thing.  If we are taxing advanced modelling software to begin to find its limits, it shows that the modelling community is stepping up to what the built environment needs to deliver better buildings.  As limitations begin to become a problem, software developers will need to address such deficiencies where previously, such deficiencies have been of very little importance.

During another session and completely unexpectedly, some of my past work was presented by Dr Robert Cohen.  This modelling shows some such issues but more importantly demonstrates how modelling can be used to highlight where buildings may not be operating correctly.

Dr Robert Cohen presenting some of my own work from a few years ago, comparing modeled building data with actual metered data.

The final presentation was by Susie Diamond of Inkling who presented an opinion paper addressing how to recognise competency of building performance modelers.  Susie referenced some of the work by our group in pursuing certification and made a strong recommendation that the ASHRAE Building Energy Modelling Professional (BEMP) scheme is introduced to the UK and that maybe it should be administered by CIBSE.

 Susie Diamond of Inkling LLP discussing how to recognise competency

As a BEMP certified modeler myself, I know that the ASHRAE scheme is heavily biased to US systems and standards.  I also know that they have worked hard to identify both ability and experience, with some of the 120 exam questions presenting a set of modelling results and the candidate is expected to interpret the results, find a potential error and identify what input may have caused the error.  Such abilities are vital but only grow with experience and I applaud the BEMP for incorporating such tricky questions.

The work I am doing with others in CIBSE BSG to bringing certification and recognition to this sector continues, with AM11 based training modules due this year.  It is intended that basic and advanced level certifications are to follow, with my aspiration being that the advanced certification provides a similar level of difficulty as the ASHRAE BEMP and thus a higher level to aim for.  Hywel Davies suggested more than a year ago that this could be a route to Chartered Engineer status, which Susie also mentioned in her paper, something I feel is vital as such a route is missing for dedicated building simulation/modeling professionals.

BEMP is a worldwide scheme, with certified modelers across the globe and thus is already available to modelers in the UK.  I became BEMP certified without leaving the UK, taking the exam at a test centre near Liverpool Street Station.  There is no official training course for it as it recognises existing ability, although being familiar with ASHRAE standards is essential.

Uptake of the BEMP scheme can be considered to be relatively small.  As of today there are less than 500 BEMP certified modelers worldwide.  This may be due to the voluntary nature and difficulty of the exam.  Don't let this put you off applying and I encourage anyone wishing to demonstrate their abilities to investigate the scheme: https://www.ashrae.org/professional-development/ashrae-certification/certification-types/bemp-building-energy-modeling-professional-certification.

As ever, I left the conference enlightened by the enthusiasm and passion of everyone involved and very much look forward to the 2020 CIBSE Technical Symposium.

Darren Coppins BEng CEng MCIBSE BEMP.

10 Years of the CIBSE Building Simulation Group

The CIBSE BSG held its 10th Anniversary event last Thursday (4th April 2019) with presentations by the BSG Chairperson Darren Woolf, CIBSE President Stephen Lisk and myself Darren Coppins.

It was April 2009 when the first meeting of the CIBSE BSG was held, chaired by Prof Hazim Awbi who remained group Chairperson for the first 9 years.  Prof Darren Woolf discusses our achievements with Stephen Lisk discussing where the next 10 years will take us.  I finish up with a summary of our progress on training and certification.

Stephen Lisk also announced the CIBSE Building Simulation Awards 2019 which will again see finalists present at CIBSE's Build 2 Perform event in November (see blog below).

The CIBSE BSG would like to thank Buro Happold for providing the event space, CIBSE for their sponsorship and support over the past 10 years (including drinks and food at the event) and to the Committee and Members of the BSG for all the support and voluntary contributions that have made the last 10 years of achievements possible.

Darren Coppins - CIBSE BSG Vice Chair

CIBSE Building Simulation Group Prize at Build 2 Perform 2018

Darren Coppins - CIBSE Building Simulation Group Vice Chair & Director at Built Physics Limited was Head Judge for the group prize event held at CIBSE Build 2 Perform 2018.  Darren discusses the event with links to the presentations below.

The CIBSE Building Simulation Group's Annual Prize culminated in 6 presentations from the prize finalists at CIBSE's Build 2 Perform event at the end of November 2018.  See the Intro to the event on the video below:

Build2Perform - Introduction - CIBSE Building Simulation Group Prize Event

Each finalist was tasked with providing a 5 minute presentation that included as much technical detail about their entry as possible, followed up with one question from the Judges, Rokia Raslan, Gabriela Costa and myself.  Each presentation can be seen below.

Gabriela, Rokia and I then went away to discuss each entry.  Whilst we were tasked with coming up with the winner and two runners up (believe me, it was not an easy task), the CIBSE BSG had lined up Matt Colmer from Digital Catapult who provided a stunning presentation on what a building services engineer can do today to plan for tomorrow, which can be viewed on the link below.

Mat Colmer - What a Building Services Engineer can do Today to Plan for Tomorrow

The panel discussion which followed can be viewed below:

The two runners up and winner were announced and all the finalists excellent presentations can be seen here:

Winner: 

Shikha Bhardwaj - Shenzhen World Exhibition and Conference Centre

Runner Up:

Santeri Siren - Parametric multi-model building performance simulation to support design

Runner Up: 

Vasiliki Kourgiozou - Dynamic simulation of overheating and passive evaporative cooling system

Finalists:

James Sander - Swimming Pool Daylight Glare Study

Karim Dada - Design By Code

Arturo Ordonez - Energy, environmental, and economic optimization of a detached house

All of the entries represent exceptional use and application of building simulation to real world projects and I recommend viewing all of them.

Details of the 2019 Prize that will be awarded at this years Build2Perform on 26th to 27th November 2019 will be announced soon.

Thanks to Greg Daines of Built Physics Limited for recording content and creating the video's.

Evaporative Cooling for Corridor Overheating Mitigation – HVAC and EMS DesignBuilder Simulation

Vasiliki Kourgiozou of Hodkinson Consultancy, presented her shortlisted case study for the CIBSE Building Simulation Group Prize at Build2Perform 2018 and was awarded runner up.

Corridor overheating mitigation is a real-life concern as it affects occupant satisfaction and the thermal performance of adjacent homes. Measures to future-proof designs in this respect are becoming even more relevant.  Vasiliki discusses her entry below and her presentation can be viewed here.

This entry was based on a communal corridor overheating assessment at the Kidbrooke Village Phase 3 development by Berkeley Homes (East Thames) Ltd. The 20-year regeneration scheme consists of various phases connected with a state-of-the art communal heating network. Corridor overheating mitigation was a significant design consideration.

A passive evaporative cooling system was proposed to mitigate the heat gains within the corridors that is energy efficient and environmentally friendly, avoiding active cooling by reducing summer temperatures by circa 5°C at peak external temperatures.

Dynamic Thermal Modelling was required to verify the effectiveness of the passive evaporative cooling system. Instead of using refrigerants and energy intensive cooling systems, evaporative systems can maintain indoor thermal comfort, cooling the air through a water wetted pad and passive adiabatic cooling. The modelling was undertaken using Detailed HVAC simulation and a script (EMS module) adapting the simulation to modulate airflows and make the fan operation energy efficient.
The simulation outcomes were also compared against real-life environmental monitoring that were undertaken in one of the communal areas of Kidbrooke’s previous phases. Both assessment methods concluded that comfortable temperatures are achieved, and the evaporative cooling system is capable of mitigating the heat gains incurred within the corridors from the communal heating network.

Written by Vasiliki Kourgiozou - Posted by Darren Coppins - CIBSE Building Simulation Group Vice Chair.

Parametric Modelling on The Shenzhen World Exhibition and Conference Centre

Shikha Bhardwaj presented ChapmanBDSP's finalist entry for the 2018 CIBSE Building Simulation Group Prize at Build 2 Perform in November 2018.  The fast paced 5 minute presentation can be seen here.  The judges were impressed with how challenges relating to the scale of the project was overcome as well as language barriers with excellent visual communication.  

Shika discusses their winning entry below.  Click the link above to view the winning presentation.

The project will provide 400,000m2 of prime exhibition when completed next year. Designed by French architectural firms Valode et Pistre and AUBEit, it contains a 1.8km long air-conditioned walkway connecting 19 hall spaces. About 50m wide, the walkway has two levels - upper for transit the lower for breakout spaces - with multiple entrances and an independent roof open to the elements at the sides.

Our work, together with V&P, included simulating the impact of wind-driven precipitation, multi-parameter optimisation of the corridor roof design and thermal and visual comfort modelling. This was achieved during a ‘small window’ less than four months before finalisation of tender design. We believe that wind-driven precipitation modelling on this scale is unprecedented.

The main outcomes of the simulations and design guidance was to:

•         Confirm distribution, pattern and specification of transparent and opaque roof elements including solar protection;
•         Propose solutions for improving lower-level daylighting;
•         Develop roof edge detailing (louvres) to minimise rain penetration towards the centre;
•         Propose solutions for improved thermal comfort through natural and mechanical means.

Simulations were carried out using XFlow software (CFD) for wind, rain and thermal studies, Grasshopper (daylighting and UTCI) and EDSL-TAS (thermal).

Written by Shikha Bhardwaj - Posted by Darren Coppins - CIBSE Building Simulation Group Vice Chair

Using Simulations To Help The Design Team To Make Well-Grounded Decisions

Santeri Siren of Ramboll was selected as a finalist for the 2018 CIBSE Building Simulation Group Awards and traveled all the way from Finland to present his entry at CIBSE Build 2 Perform 2018.  Santeri discusses his entry below which was awarded Runner Up.  You can see Santeri's presentation here 

Too often energy simulations are used only to make the mandatory building code calculations or to verify the effects of already made design choices. This is truly a waste of potential because energy simulations can be used in making those design choices and to provide real benefit to the project if used correctly.

Our project was all about using simulations to help the design team to make well-grounded decisions and thus create a real impact on the design choices made in a construction project of an apartment building in Helsinki (120 apartments).

I will write about three important steps for effectively using a simulation study in a construction project.

The first step is to plan and run the first simulations at very early stage in the design schedule when the design parameters are not yet locked.

In this project we started to plan our simulation study with other designers before the architect had even released the first version of building floor plans. Thus, we were able to flexibly choose meaningful design options to study with the simulations for example window sizes, glazing types, cooling systems, envelope insulation and AHU options.

The second step is to have enough extensive study to be able to form a comprehensive overall picture and add value to the project. In this case we studied 1840 different combinations i.e. 1840 possible ways to design the same building. For each of these possibilities we calculated the building energy consumption, energy CO₂ emissions, local building code energy rating, building code indoor air requirements, investment costs, lifecycle cost and indoor air quality study for every bedroom and living room.

This way we had enough data to manage many aspects on how different variables affect the project. E.g. if you change the window sizes you can see how it effects the energy consumption, indoor air temperatures, required cooling system and what is the influence on the cost etc. There were many interesting cause and effect relations to be found.

The whole point is in managing the overall picture and understanding how one change will affect multiple areas of the project and building performance.

The final step is to present all this information to other parties in an approachable way. This is extremely important because without an efficient way to present and manage the results all your hard work can go to waste. Luckily there are good software’s in the market that can be used to do this. We created interactive visualizations of the data that are easy to use for non-technical people also.

Results were studied by the design team in several meetings and were used to make well-grounded decisions and steer the design choices to optimal direction

Written by Santeri Siren, Posted by Darren Coppins - CIBSE Building Simulation Group Vice Chair