Energy efficiency in construction projects

Intro To Net Zero Energy Buildings

The issue of climate change is looming over our heads now more than ever. If you operate within the construction industry, being reminded of the fact that the building and construction industry produces 39% of all the carbon emissions in the world probably does not come as good news either. So what can we do to reduce that impact? Better yet, is there a way to cancel out the negative impact almost completely? That’s where the idea of Net Zero energy comes in. The U.S. Department of Energy defines it the following way: a zero-energy home is “a high-performance home which is so energy efficient that a renewable energy system can offset all or most of its annual energy consumption.”

Put simply, a Net Zero Energy Building produces as much energy as it uses, on an annual basis.

Ensuring energy efficiency through the effective design and monitoring of building operations can result in significant reductions in carbon emissions. Construction involves mainly two kinds of carbon emissions: operational and embodied and operational. Embodied carbon refers to the carbon released during the extraction, manufacture, transport, and construction of all materials, products, assemblies, and systems installed in a building project, while operational carbon refers to the carbon emitted during the operational stage of a building.

With net-zero principles incorporated in and accounted for, for the entire building lifecycle, both operational and embodied carbon emissions can be reduced drastically.

To know more about the significance of Net Zero, its main components, and how to achieve it, read on.

Why is it important?

The need for Net Zero should be obvious if it isn’t already. Looking at the big picture, it’s our tool to stabilize climate change – namely through the drastic reduction of carbon emissions. Climate scientists have claimed that if carbon emissions are not monitored and reduced by the year 2030, the risks of natural disasters will increase significantly and eventually reach a tipping point of irreversible change. The Intergovernmental Panel on Climate Change reports this tipping point to be between 1.8 and 3.6 degrees Celsius.

On a smaller scale, achieving Net Zero will result in long-term financial benefits for builders and users alike. As Jourdan Younis, Managing Director at Alpin Limited, puts it:

“As a business operating in the construction field, be it Developer or Architect, Net Zero should be the top priority in terms of future strategic direction.”

For one, a zero-energy building is one with greatly reduced operational energy needs. Not only will owners get to enjoy a reduced cost of ownership due to reduced energy requirements, but they will also be able to avoid the negative consequences of possible future increases in energy prices.

Considering Net Zero is slowly becoming the global goal in the built environment, the construction costs of a Net Zero building will also be lesser than that of later retrofitting the building to attain Net Zero. A Net Zero building should be considered an investment, having a higher resale value, especially at the current time, as the demand for this kind of building is steadily increasing owing to the number of benefits they offer, including tax incentives, long-term savings in operations and overall investment cost.

Moreover, if a building produces more energy than it consumes this extra energy can be sold to community power sources, allowing the building owner to pocket some extra cash.

Moreover, Net Zero buildings are more comfortable and better for occupant health, This is because closely following Net Zero principles ensures better air quality, better lighting, the use of non-toxic materials, acoustic as well as thermal comfort.

What are the main elements?

Achieving Net Zero consists of three main steps: creating an efficient design, energy conservation, and implementing energy production methods.

Efficient Design

The first step is ensuring an efficient building envelope with double insulation, and exceptional air sealing; locating the building on a suitable site, identifying an ideal building orientation that optimizes daylight, and using low embodied carbon construction materials to ensure healthy interiors and thermal comfort.

Energy Conservation

This next step is deciding on the most fitting energy efficient equipment and techniques to be incorporated into the design of the building. This can include heating and cooling systems, shading devices on windows to reduce load on HVAC systems, automated settings and occupancy sensors on HVAC and lighting systems to turn them off when not needed, as well as training occupants to induce change in their behaviours and habits when it comes to using resources.

Renewable Energy Production

Hence, through energy efficiency, the demand for energy is reduced, and the reduced demand is fulfilled through the supply of renewable energy from systems built in to the building design (onsite) or from a community energy supply (offsite), such as an electrical grid. In the event the building does not produce enough energy to fulfil its demand, it can borrow energy from the community grid, and similarly export any extra energy created to the grid when not needed. In such a case where the energy production of a building exceeds the usage, it is called a Net Positive building.

Sources of renewable energy onsite include active energy producing appliances such as solar photovoltaic panels. Solar panels can be attached to the roofing of the building/car parking and are capable of converting sunlight into electricity to be used to operate building systems and appliances. Solar heaters can also be installed to heat water for the use of building occupants, and reduce the electrical consumption that would be required to do so otherwise.

How do you achieve Net Zero?

So how do we achieve Net Zero in our buildings? By incorporating Net Zero principles through asset and operational assessments.

The costs of a Net Zero building encompass the high initial costs of finding experienced builders to implement Net Zero principles. However, this can be easily circumvented through the appointment of a qualified Consultant to plan and monitor the energy emissions of the building.

Here are the ways a consultant can help you achieve Net Zero:

Asset Assessment

An asset assessment looks at all the building assets, which include its building envelope, the HVAC and lighting systems, energy needs, and so on. Through these assessments, we are able to identify the areas that consist of high embodied energy and carbon emissions, and therefore develop strategies to reduce them.

One way to do this is through a Life Cycle Assessment (LCA):

An LCA allows for the identification of a building’s environmental hotspots, or areas producing the most embodied carbon emissions. Alternative materials with a lower impact can be identified based on the LCA. As Alpin’s resident LCA expert, Sadaf Ghalib describes it this way: “By analysing the environmental aspects and potential impacts of a product, process, or service used in the building, one can identify which of these are potential hotspots that should be addressed during the early design stage itself. Choosing better alternatives such as recycled components or locally available materials would be preferable to manage the key impact categories, namely greenhouse gas emissions, ozone depletion potential, acidification and eutrophication.”

Yet another great tool to use for asset assessment is Energy Modelling:

Energy Modelling allows builders to identify which energy-saving measures will best allow a project to achieve Net Zero, and how to approach the design of building assets at the lowest possible cost. An assessment of the energy these assets use gives a pretty accurate idea of where savings can be made, and it comes in handy as proof of a building’s ability to achieve Net Zero before its actual construction. Moreover, it can allow for the calculation of the necessary size and cost of the solar panelling the building requires, for example.

Last but not least, Envelope Commissioning is a great method to assess the performance of building’s structure itself:

Envelope commissioning involves evaluating the performance of a facility envelope in order to determine whether a building is meeting the objectives and requirements set by the owner,  and optimizes the performance of the building envelope by identifying and correcting uncontrolled leaks or intrusions at building intersections. A huge part of envelope commissioning is the inspection and testing of various systems to verify if the assemblies react as designed. For example, air tightness testing is used to identify any air leakage, and when fixed this leads to higher energy efficiency. A water ingress test involves finding the possibility of water intrusion in fixtures such as doors, windows, skylights, and other assemblies, so as to reduce moisture penetration and resultant issues, e.g. mold growth and detrimental indoor air quality for occupants.

Improvements to building enclosure can be achieved through simple actions such as re-sealing joints or repairing window frames, and without costing a lot. “Attention to details, junctions, and system dynamics can make the difference between efforts that actually improve building performance, and those that waste more energy than they save.”

Operational Assessment

The only way to identify if a building is truly achieving Net Zero is through assessments of energy use and resultant carbon emissions, done during the actual operational phase of a building. This can be done through metering, i.e. measuring and monitoring energy consumption on a periodic basis. Establishing meters on the renewable electricity generators, lighting fixtures, plug loads, and HVAC systems makes sure that the efficiency of all these equipment can be recorded and monitored, so as to take corrective action where necessary.

After the data has been collected from an operational assessment, it can be analysed and used to inform future improvements to be made to the building to either achieve its Net Zero Goal or outperform it. For example, the results could be used to consider the integration of building automation or any behavioural changes that may have to be induced in building occupants through the implementation of policies such as establishing minimum efficiency standards for appliances and equipment.

How can rating systems help achieve it?

Green Building rating systems have been increasingly popular in the construction industry in recent years and have greatly improved the progress of sustainability in the built environment globally.

While there are some that were created specifically to address the achievement of Net Zero, many others partially incorporate Net Zero principles within them, and be used as a great tool to achieving Net Zero buildings. The following are some of the most renowned rating systems that can help in your Net Zero journey:

  • LEED Zero Energy is an addition to LEED’s impressive catalog of green rating systems that recognizes building projects that achieve Net Zero energy, through a focus on at least one of the following: Net Zero carbon emissions, Net Zero energy use, Net Zero water, or Net Zero waste.
  • The BREEAM rating system’s Energy section is designed to encourage the reduction of energy use and carbon emissions through the assessment and optimization of three main metrics: the building’s heating and cooling energy demand, its primary energy consumption, and the total resulting CO2 emissions.

Alpin case study: Confidential Pavilion, Dubai, U.A.E.

One of the projects Alpin has worked on, Confidential Pavilion project, won the award for Zero Energy Building of the Year at the 2019 MENA Green Building Awards. This project is a great example of Net Zero building, and we’ll show you how we achieved this.

The initial project requirements were to target zero greenhouse gas (GHG) emissions and an embodied carbon emission level of 8.875 g. It also targeted a BREEAM and WELL certification, along with compliance with the Dubai Green Building Regulations.

So, what did we do to ensure the building reached Net Zero?

For one, the water heating was done through 100 percent solar heating. All water fixtures were low-flow and equipped with sensors, and taps had aerators in them to reduce water wastage. Automatic leak detection systems were also installed so that any leaks could immediately be reported and taken care of.

Moreover, all lighting used was LED installed with occupancy sensors. As for energy generation, the project had solar PV panels installed on the building roof as well as on the associated car park roof. Most importantly, metering was established for all energy-producing and energy-consuming building fixtures to ensure that proper operational assessments and consequent improvements could be made.

Due to the implementation of all the aforementioned measures, the estimated annual energy consumption was recorded to be 77,600 kWh while the Estimated Generation was 136,620 kWh, meaning a net energy positive outcome of 59,020 kWh! Moreover, the project was also able to attain energy efficiency before the implementation of solar power of 25% higher than the ASHRAE 90.1-2013 baseline (a well renowned sustainability standard).

What the future of Net Zero looks like

As you can see, Net Zero is one of our best tools to fight climate change through reducing energy usage, and several nations have already taken up promises to fulfil global climate goals. The most well-known of these is the Paris Agreement, signed in 2016, which pushes participating nations to enforce its requirements and take measures to respond to climate change by maintaining the global temperature rise at 1.5 degrees Celsius.

The Net Zero trend also closely aligns with Goal 13 of the UN’s sustainable development goals, Climate Action, which aims to make a shift to a low-carbon economy and encourages the integration of climate change measures into national policies and strategies by the year 2030.

These types of global commitments seem to indicate that we can expect to see an upsurge in the implementation of Net Zero principles.

Want to have your next project achieve Net Zero? Get in touch with a consultant who can help align your project requirements with Net Zero principles.

Written by Fairuz Zakir; Edited by Sadaf Ghalib

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