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For many building types, maintaining space conditions will account for a significant proportion of the overall energy consumption. With the effects of climate change expected to increase the external air temperature, buildings will see a shift toward an increased cooling need. If we are going to reduce our carbon emissions whilst minimising running costs then the onus will be on designers to correctly ensure their plant design is optimised. The key will be to accurately predict the cooling energy demand and recognise how a considered system will operate in practice. Not doing this accurately could lead to increased risk exposure when the building is operational. So what considerations should designers be recognising in the early stages?
If we start by looking at the UK compliance route which typically uses a Seasonal Energy Efficiency Ratio (SEER) as a means of determining the cooling energy. SEER figures are intended to represent a weighted system efficiency that takes into consideration performance at varying part load conditions and at varying ambient temperatures. Manufacturer published SEER values are based on a specific set of conditions that in all likelihood will be very different to the range of conditions that a particular building is likely to operate within. While SEER values are useful for designers so to compare a range of products on a like for like basis they do not necessarily reflect the true performance when that cooling plant is then operational.
Typically SEER’s used in UK Compliance calculations will be based on the following standardised conditions:
|Part Load||Weighting Factor(Office Building)||Weighting Factor(Unknown Profile)||Air Cooled Chillers – Ambient Dry Bulb Temperature||Water Cooled Chillers – Condenser Entering Water Temperature|
The operating conditions for different part load conditions are used for benchmarking chillers internationally and do not necessarily even reflect the UK’s climate.
For many parts of the UK the air temperatures assumed for the SEER calculation at a 75% and 100% part load will rarely be observed. If the building is not an office type and the load distribution is unknown then the four part load points will be weighted equally putting an even greater significance on the plant at a high outdoor temperature when the system will be operating a lower efficiency.
The London TRY05 weather file for example has a peak external temperature of 31.8°C and exceeds 30°C for only 10 hours of the year but based on the standard weighting factors a 33% weighting factor should be applied to the performance at this condition
It should be remembered that simulations can be used to establish an appropriate SEER which permits a more accurate and indeed more favourable assessment.
Real Building Analysis
In many instances design consideration is still only given to the peak cooling demand to ensure the selected plant has sufficient capacity to safeguard the cooling plant needs. However it is important for designers to push on and understand the expected demand load distribution within the design. This is simply the case because a building may frequently experience part load conditions that the plant cannot meet efficiently, or its demand is lower than the cooling plant’s minimum turndown, or even the cooling system is an innovative design with multiple components where coolth is captured from many sources.
Take the example of when the cooling load demand is lower than the chiller’s minimum turndown, it will typically cycle on and off with this behaviour leading to inefficient performance. This in turn applies unnecessary stress on the plant which may result in faults and in places failure, but most certainly increased maintenance costs. Who will bear this burden? A building owner should not feasible expect this process after their investment has already been made.
To solve this step then the design should consider how the range of the cooling plant output can be extended through a modular chiller design. The chart below compares this range where the chillers can operate continuously for a single chiller and multiple chiller configuration.
While the chart above demonstrates that only a lesser proportion of part load conditions will lead to chiller cycling, this part load range can still be a common condition especially if the chiller plant has already been oversized.
As well as increasing the operational range of the chiller output, sequencing can be utilised to maximise the cooling plants operational efficiency by either running single or multiple chillers to achieve the best operating condition. The illustrative example below demonstrates a chiller’s COP at varying part load conditions. Alongside the COP, the load frequency is displayed indicating how often the cooling load falls into a particular range. This illustrates how sequencing multiple chillers can be utilised to provide smaller part loads efficiently.
The following series of charts illustrate how implementing multiple chillers and with sequencing can meet building loads more efficiently. The green bars represent the frequency a particular load condition occurs and in the example we see a significant number of hours where the cooling demand is relatively low. The grey line illustrates the systems efficiency at that part load condition.
The first example represents a single chiller serving the building where it operates at a poor efficiency across many hours. The SEER in this instance is 3.68.
In the second example the same cooling demand is now met by two equally sized chillers which allows smaller loads to be met more efficiently than previously. The SEER now increases to 3.98.
The final example uses two unequally sized chillers to go further in efficiently meeting the building loads. Now the SEER has risen again to 4.05.
The above examples are illustrative but are intended to demonstrate how the impact of plant selection and control can influence the performance of a building.
The efficiency of a building cooling plant is sensitive to a number of considerations including water loop temperatures, part load conditions and the ambient temperature, all of which continually change across the year. Only within a dynamic simulation can the building plant be modelled in the required detail to predict the true operation. With feedback from the dynamic simulation designers can confidently understand the HVAC plant operation and its responses to the pressures put on the building. Modelling the intended operation during the design stage will help identify potential risk far in advance to ensure an efficient and optimised plant.
Over the past two years IES has collaborated with Somfy and Philips Lighting to analyse their shade & light combined solution “Light Balancing System” and its potential impact on energy savings. Most recently IES analysed the potential energy savings of a pilot project, the Onix office building in Lille. In this blog post, we invited Christelle Granier from Somfy to tell us a bit more about the collaboration, why they chose to work with IES and the importance of manufacturing companies integrating with the world of Building Physics and Building Performance Analytics…
We (Somfy and Philips) wanted to find a way to provide building design professionals with an effective and worthwhile product that would fit in with a holistic design process and help them to design both comfortable and energy efficient buildings. To do this we needed to validate the impact that the Light balancing system had on energy consumption.
To us, IES was the best choice because it is well known for its advanced dynamic simulation tools with the capabilities to conduct the most accurate analysis. After working closely with its Business Development Consultant, Luc Delestrade for over a year, he taught us a great deal which changed the way in which we demonstrated our solution.
More and more building regulations are being implemented worldwide and current ones are becoming much more stringent. We knew that in order to help industry professionals comply with these regulations we had to validate the Light Balancing System and prove its effect on a buildings energy consumption. In our pilot study, the Onix Building in Lille we proved that the System could reduce energy consumption by 29% in one year.
We understand that Building Physics and performance analytics is key to validating manufacturers building products. Collaborations such as this one are extremely important for the future of sustainable building design. IES was vital in helping us prove our work. Automated shading should be part of the lifecycle management of the building. Working with IES helped us to democratise this product and make it more accessible to more building professionals.
The collaboration was a deep learning experience on both sides. We now have a much better understanding of where the Light Balancing system fits in the building lifecycle analysis process and how it effects occupant comfort and energy efficiency. The product should be analysed as part of a holistic model looking at HVAC, lighting and façade which includes automated blinds.
I’d like to extend a big thanks toIES, our collaboration helped to leverage our knowledge and understanding of building physics and performance analytics. I look forward to a future that holds further industry collaborations that help validate manufacturer products and their potential energy savings through building performance analysis.
What do you get when you challenge nine interdisciplinary teams to design a net zero (or below) 50,000 ft2, 3-story Outpatient Health Care facility in Omaha, Nebraska? You get ASHRAE’s Lowdown Showdown, an energy modeling competition that showcases the talent and innovation of those in our industry using building performance analysis software.
Last year, Team IES won Best Energy Use Results and we were delighted that the winning streak continued after the team were awarded Best Workflow at SimBuild 2016 in Salt Lake City on August 11th.
This year’s IES team – going under the name Insane Energy Savers – consisted of the following members: Kent Beason, Joanne Choi, Cory Duggin, Alexandra Gramling, Ken Griffin, Amy Jarvis, Shona O’Dea, Igor Seryapin, Irina Susorova, Tristan Truyens, Brian Tysoe, Scott West and Xiangjin Yang.
Our design started by modifying the massing and program to be as climate responsive as possible, while still maintaining the core mission of an outpatient surgery center. Any non-critical spaces were migrated to the second and third floors where a common atrium was added in lieu of the circulation program areas. Exam rooms and office spaces were placed along the perimeter to allow cross ventilation from them through the atrium. Based on wind roses for the shoulder seasons, when natural ventilation is most viable, the building was rotated for the south façade to be in line with the predominant south eastern wind.
Stair stepping the south façade allows the building to self-shade for the entire cooling season and allows for passive heating in the winter as well as passive reheating of air-change dominated spaces on the first floor. Since Omaha has a significant heating season, the R-value of the walls, roof and glazing were optimized to reduce heat loss.
The air change constraints in the first floor program caused us to consider it separately. A separate dedicated outside air system (DOAS) is used for the critical spaces coupled with earth tubes to precool and preheat the required ventilation air. The non-critical areas use another DOAS with a south facing vertically mounted transpired solar collector for preheating since the windows will be open for cross ventilation during much of the cooling season. All spaces and both DOAS use a geothermal, water-cooled VRV system for their cooling and heating.
The tilted roof of the atrium was designed to hold photovoltaic panels with a 19.6% efficiency. Wind turbines were also used to produce the remainder of the energy required to get net zero.
Take a look at the poster below for more info on the project’s energy saving strategies.
An ‘Insane’ Effort
In my role as team mentor, it was awesome to see first-hand how our talented team used the Virtual Environment to complete this challenge. A lot of work was put in and it paid off when they picked up their award for Best Workflow.
It was a great effort by all involved – not just the insane ones – and it’s fantastic how each team came together to demonstrate how energy modeling tools can be used to make such a positive impact on our built environment. Bring on next year’s challenge!
Click here to see view the Insane Energy Savers’ Lowdown Showdown presentation slides.
One of the greatest challenges that our societies have ever faced is how to drive energy efficiency at the building, district and city level. Sustainable Places is an International Conference held each year across Europe to gather scientists, researchers, and engineers, from both academia and industry to discuss the latest state-of-the-art advances in this area.
This year, its being held in Anglet, France and IES is involved in a big results workshop for FASUDIR, as well as presenting on work currently in progress on the iURBAN and NewTrend projects. While other projects RESSEEPE and Energy in Time are also hosting in-depth workshops.
The show aims to facilitate innovative solutions for renovation and new construction to ensure the long-term environmental sustainability of ever-growing, densifying urban areas, in a resource-constrained world. Information and Communications Technology (ICT), along with other key research domains (energy, materials, methods and practices, etc.) will be at the core of the conference.
Join us at the show if you’re heading along, or catch up with our post show blog.
FASUDIR Results Workshop
Thursday 30th June, 9am-12.30pm, Nick Purshouse
FASUDIR Linked Workshop/Paper: Historic Cities in Transition
Wednesday 29th June, 4.30-6.30pm
iUrban Paper Presentation
Thursday 30th June, 9am, Mike Oats
NewTrend Presentation: District Renewal Workshop
Wednesday 29th June, 11am-4pm Nick Purshouse
RESSEEPE Workshop: Public Building Retrofitting
Wednesday 29th June, 2-4pm
RESSEEPE Paper Presentation
“Innovative technologies for retrofitting: Coventry University as a Living Lab”
Wednesday 29th June 4.30pm
Energy in Time Workshop: Building Operations & Maintenance
Thursday 30th June, 9am-12.30pm
I recently conducted an energy survey at a new healthcare facility and a couple of headline numbers jumped out which I thought could do with some further investigation and validation. So the focus of this Post is specifically around the application of Energy vs Cost Modelling within the Building Performance Analysis industry.
So here are the facts:
The story sounds ok so far until you consider the total Project Value, a £29-million design/build cost. If we do some very basic lifecycle cost modelling the numbers look like this:
[Note: No Utility Rate increases, NPV or Discount Rate allowances made in this basic calculation]
As the calculations stand this facility would therefore take 30-years to have a cumulative energy spend of £3-million.
Let’s say that 20% energy savings could be made fairly easily via a £20k energy efficiency spend and that a 1-year ROI would be achievable. So a £20k up front spend on energy efficiency measures generates £20k worth of savings by the end of the first year. Assuming this £20k reduction could be maintained for the remaining 29-years a cumulative saving of £580,000 could be made over the 30-year range.
A 20% saving is a 20% saving and who wouldn’t want an extra £580k in their annual budget, but is it really worth waiting 29-years for?! It seems like such a long time to wait.
Now if we look at the £580k from the total Project Value perspective (£29-million) it’s works out as only 2%.
So here’s the point. If 2% could be shaved off the total Project Value up-front at Design/Build stage the £580k saving becomes money up front, cashed in the bank from Year Zero – money that doesn’t need a 29-year wait to get back in hand. To me this sounds like a better deal for any building Owner/Operator?
If we look at this from the Building Performance Modelling perspective it gets interesting. We spend fees on Energy Modelling and associated analysis for Green Building Certification schemes (BREEAM, LEED etc) but do we really use these intelligent 3D models to their full potential from a Cost modelling perspective?
Surely with the BIM analysis models that are being developed for purposes of Building Performance Analysis (Energy, Daylight, Natural Ventilation, Overheating studies etc) it’s an easy transition to further develop these models as accurate Cost models? In this way more time and resource could be used on predictive modelling of Cost based scenarios? We’re all well versed in scenario based energy modelling (e.g. multiple changes to a wall U-values, HVAC plant efficiencies etc) and we can predict the resulting % energy savings such measures will have against a baseline figure, but do we really consider these ‘energy’ measures from a Cost perspective?
I will continue on this same theme in a future Post but am interested to hear the industry feedback on this to date. How many Building Performance Analysis teams out there are actively involved in BIM based Cost modelling on a day-to-day basis? Where do you get the data for the Cost models? Is there more that the ‘modelling’ industry can do to populate better Cost models – or is it simply a bridge too far with insufficient Cost datasets currently available? Is a dedicated Project Quantity Surveyor needed for a detailed Cost analysis or can the modelling industry do more to support early stage scenario based Cost modelling of this nature?
Intended Nationally Determined Contributions (INDC’s) form the basis of the COP21 Paris agreement goal of keeping global temperature rise “well below” 2⁰C above pre-industrial levels. Nations outline their INDC plans on cutting their post-2020 emissions.
There is a legal requirement for these INDC plans to be revised ever five years. There is no requirement to state how the reductions will be achieved and there is no legal requirement to achieve the INDC targets. This is surely a major weakness.
The INDC’s of the largest greenhouse gas emitters have set their targets: China has targeted a 60-65% reduction in greenhouse gas emissions per unit of GDP by 2030; the United States, has targeted a 26-28% reduction by 2025; and the European Union has targeted a 40% reduction by 2030.
By maintaining the status quo in terms of carbon emission it is anticipated that the global temperature rise will reach 3.6⁰C by 2100. A recently published assessment (http://climateactiontracker.org/) suggested that the emission reductions currently outlined in the currently submitted INDC’s would result in a global temperature rise by 2.7C.
This figure was generated by the Climate Action Tracker (CAT). CAT is an independent scientific analysis, produced by four research organisations, tracking climate action and global efforts towards the globally agreed aim of holding warming below 2°C.
CAT categorise each of the submitted INDC’s as follows:
|Inadequate||If all governments put forward inadequate positions warming likely to exceed 3–4°C.|
|Medium||Not consistent with limiting warming below 2°C as it would require many other countries to make a comparably greater effort and much deeper reductions.|
|Sufficient||Fully consistent with below 2°C limit.|
|Role Model||More than consistent with below 2°C limit.|
Of the 31 INDC’s that have been reviewed:
It is important to remember that these INDC’s are pledges and not legally binding. None of these countries have a clear plan on how to achieve their INDC targets. So without a coherent plan it is fair to assume that it is more likely that the IDNC targets will be missed rather than exceeded.
Who am I to contradict the President of the USA, but I am delighted to tell you that you don’t have to worry about the planet – the Earth will survive global warming.
Why do I know this? Well there is scientific evidence that shows that during the last few hundred million years the Earth has been both much warmer and much colder than it is today. In both extreme cases Earth has survived.
Consequently, I do not think our 1.5⁰C or above increase in global temperature will damage Earth.
It will be 7.5 billion years before the Earth will be consumed by the sun which will have become a red giant. This is so far in the future it is not a concern. So what is the problem?
Loss of Life.
Five major mass extinctions have been identified over the last 500 million years or so. In the most extreme cases almost 95% of life became extinct.
The most famous mass extinction killed off the dinosaurs. This was extremely fortunate for humans as it created the opportunity for mammals to occupy the space vacated by the dinosaurs. This obviously led to us – Homo sapiens – becoming the dominate species.
Homo sapiens have been around for a hundred thousand years. In that time species such as the mammoth and the sabre-toothed tiger have been lost. Whether that has been due to humans or not is questionable. However, the same cannot be said for the Dodo and many recent species that have become extinct.
However, our interaction with the Earth is causing an increasing number of species to disappear. Scientists believe that we are in the middle of the sixth mass extinction. Human activity such as burning fossil fuels, deforestation, dams, over fishing, etc. demonstrate that we are the principal cause of this current mass extinction. Scientists have estimated that by 2100 50% of current species will be extinct.
What about us?
Humans are highly resilient. What happens to us depends upon what action we take to stop global warming. We face droughts, floods, lost top soil, food and water shortages, wars over resources and mass migration, etc. By 2100 will we have smart cities or no cities? Will we be going forward to a much better global society or devolving back to the ‘Dark Ages’ e.g. post Roman Empire?
It is our choice.
One thing is for sure – The Earth will be OK.
The photos of the delegates with big smiles, applauding and raised arms clearly illustrate that COP21 was a major success. Delegates went home and could report a major achievement. It was a massive step forward, achieving a global commitment to significantly reducing carbon emissions thereby substantially reducing the impact of global warming.
Should we all rejoice?
What are the key agreed targets from COP21?
The agreement is the first where all countries have committed to cut carbon emissions. Some aspects of the agreement will be legally binding, such as submitting an emissions reduction target and the regular review of that goal.
Every five years countries will have to declare their ‘Intended Nationally Determined Contribution’ or INDC. The idea is that every five years countries will set new, more rigorous targets.
What won’t be legally binding will be the emission targets. These will be determined by nations themselves and the INDC need not be a meaningful target. For example a study on 31 of the INDC’s submitted so far show over 50% are inadequate and likely to lead to global temperature rises of 3-4⁰C.
In addition, whilst it is legally binding that the INDC targets are set, it is not legally binding that you need to achieve them. This is a major weakness.
To date, 147 countries have submitted their INDC’s. If these targets were to be achieved they will only reduce global warming to 2.7⁰C. This is well above the 2.0⁰C goal of the Paris Agreement.
Whilst ambitious goals have been set at COP21 it is left to others to work on how to implement the goals.
These INDC’s will require serious political commitment to deliver the targets, particularly if it requires reducing economic growth or is too expensive to implement.
US President Barack Obama has hailed the COP21 agreement as “ambitious”. I am uneasy with the word ‘ambitious’ in this context. He also admitted that the deal was not “perfect”, he said it was “the best chance to save the one planet we have”. Again I don’t like the non-committal tone of the message.
In addition, China’s chief negotiator Xie Zhenhua agreed with the President and he also stated that the deal was not perfect.
It appears that COP21 achieved much good will and clearly a verbal intent to take action, but what will happen if one or more countries renege? Will the agreement collapse like a pack of cards?
The big question is will there be the political strength in each country to implement the measures to tackle this problem?
Buildings, cities, manufacturing and industrial processes will play a major part of a countries carbon reduction strategy. The problem each country faces is that there is little or no commercial lobby for energy efficiency. The lobbying is done by the renewables and clean tech sectors. Whilst these are important there is little point in renewables or clean tech if buildings are wasting 30%-50% of their energy in the first place.
Is it surprising that if buildings are not made energy efficient then more renewables and clean tech will be required?
Unfortunately, I fear the success of COP21 could be more of an illusion than a triumph. Put the Champagne back into the vault, it will be a long time before we will know if COP21 was a success or not.
This rush, perhaps caused by the Environment Agency’s (EA’s) recent communication to all organisations expected to be compliant, seems to suggest that a significant number are going to be taking advantage of the EA advising that it would not normally expect to take enforcement action for late notification received before 29th January 2016. Which essentially, in all but name, extends the deadline until the 29th January 2016.
However, there are a number of conditions attached to this, which those wanting to take advantage of it should be aware of. If companies know they are not going to hit the 5th December deadline they still need to inform the EA before this date and provide key information including details on the appointed Lead Assessor. This should be done via an online portal set up by the EA.
The EA has been very clear “Qualifying organisations that do not complete and notify a compliance assessment by 5 December 2015 will be in breach of the regulations and at risk of enforcement action and penalties. Enforcement action will not normally be taken provided your notification is received by 29 January 2016. For organisations committing to achieving compliance through ISO 50001 certification, enforcement action will not normally be taken as long as notification is received by 30 June 2016.”
They go on to advise organisations to do as much as possible prior to the 5th December deadline and to record details of this in your Evidence pack. The great news is that our software has been reviewed by the EA who have confirmed that they will accept it as part of your Evidence Pack – all they need is a login which we will supply free of charge.
So with only 20 working days to go we hope that you are just finalising everything and getting ready to submit your notification of compliance. However if not then please join us on Thursday 19th October for our latest webinar on ESOS Auditor to find out more about making your ‘intent to comply’ notification and also how our low-cost online ESOS Auditor tool can be used to prove how much you have done before the deadline and therefore mitigate any risk associated with late compliance.
You may remember we blogged back in August about our participation in the ASHRAE LowDown Showdown competition. Well, we have some great news… Team IES won the Best Energy Use Results category! Liam Buckley coached the winning team, fighting off competition from seven other practitioner teams, representing software-specific tools from: Autodesk, Carrier, DesignBuilder, eQUEST, EnergyPlus, Sefaira, and Trane. We asked Liam to tell us more about the winning entry and the winning team…
Our brief was to design a three-story; 53,600-square-foot office building that included a number of specific design challenges, but also encouraged design creativity. Projects were judged on energy efficiency, design creativity, workflow innovation, teamwork and collaboration.
Obviously, the team decided to make the challenge even more challenging by locating the building in downtown Boulder, where the climate experiences vast and extreme variations including annual external conditions ranging from (-4° F to 93°F); (6% -100% Relative Humidity) and commonly occurring daytime-to-night-time temperature swings of 35°F.
The team considered 150+ Energy Conservation Measures (ECMs) and eventually chose 25-30 strategically sequenced ECMs, which included daylight harvesting controls; natural ventilation with exposed thermal mass and automated night-purge control; an air-to-water heat pump; energy-star equipment; plug load schedules from metered ZNE evangelists; fixed and dynamic solar shading; airside heat-recovery wheel; IT server virtualization; radiant floors for improved thermal comfort; an optimized electric lighting design; a high-performance envelope with heat-mirror glazing and insulated panels. Finally, the integral ECM of the building showcased a passive negatively-airflow-integrated atrium, which considered all climatic eventualities.
To compliment the solar hot-water heating system, which was coupled with electricity-generating PV panels, additional explicit onsite renewable energy technologies included 5 Vertical Axis Wind Turbines. These were further optimized by the building architecture.
Our team wanted to ensure that the design would not only meet net-zero standards for next year, but that 50 years down the line, would still be operating at net-zero energy. To ensure this, we morphed the TMY15 weather data 50 years into the future (to 2064) and planned for the addition of two building-integrated evaporative down-draft cool towers that assist with cooling, which would keep the building operating at zero net energy despite higher cooling loads.
I was thrilled that our team won this award for Best Energy Use Results. The team worked really hard; although the IESVE is a powerful software suite with vast capabilities, the tools are only as good as the people using them, and we had an incredible team using them. They deserved it. It was a real pleasure working with such a talented group of people.
The team members were: Anna Osborne (Integral Group), Ben Brannon (Arup), Shona O’Dea (DLR Group), Megan Gunther (Affiliated Engineers, Inc.), Cory Duggin (TLC Engineering for Architecture), Greg Romanczyk (exp) and Scott West (HKS Inc.).
Our team has created a video presentation of the winning design which can be viewed at https://youtu.be/7V5LktxK5ig.