Rehau - Designing Sustainable District Heating Systems
The heating industry has a major role to play in the UK’s journey to net zero carbon emissions, and low-carbon district heating schemes are becoming increasingly popular. Here, Alexandra Leedham, Technical Leader – Renewable Energy at REHAU, explores why pipework choice is important with this technology.
District heating systems that supply heating and hot water via pre-insulated pipe networks from a centralised heat source have grown in popularity among building professionals due to their ease-of-maintenance and installation. The UK Government has already invested significant funds towards district heating as decarbonising heat is a key challenge to reach net zero. To encourage the uptake of low carbon district heating schemes, the Green Heat Networks Fund (GHNF) starts in 2022, with a transition scheme starting in July 2021.
Heat pump-based district heating systems will benefit from the proposed tenth Standard Assessment Procedure consultation (SAP 10.2), which sets standards for a new lower emissions factor for electricity, advocating heat pumps as a more sustainable solution. Compared to the SAP 2012 metric of 0.519 kgCO2/kWH, starting from SAP 10.1 a value of 0.136 kgCO2/kWH has been proposed – a 75% improvement in heat pump-derived electricity carbon savings from previous figures.
Most UK heat networks are third-generation, with water circulating at 70-95oC and often heated via fossil fuel-powered boilers. Yet fourth-generation systems with a lower 50-60oC flow temperature are now being implemented, with the reduction in network-wide heat loss making them more cost-effective, efficient and compatible with sustainable heat pump and waste heat sources used on eco-conscious projects. Their centralised design also allows for quicker installation than individual boilers, with less maintenance required.
This rising popularity makes pipework material choice an important aspect of ensuring efficient delivery of heating and hot water. Though traditionally made of steel, all-polymer systems are now viable as the material suits lower circulation temperatures, lowering heat losses while making installation easier.
Using reinforced polypropylene (PP-R) as the network’s main spine, for example, allows polymer-based schemes to provide heat loads up to 16MW. Flexible, coiled PE-Xa pre-insulated pipework can be easily connected to this spine, ensuring cost-effective installation for building professionals extending networks. This, alongside the material’s lifespan of over 50 years, highlights polymer’s role in sustainably futureproof buildings’ utility demands.
Additionally, a PP-R pipe main spine can reduce pressure losses by up to 19 per cent compared to steel solutions. For maintenance-conscious contractors and developers, minimised corrosion risks result in less system failures and ensuing expensive repairs. PP-R is up to 37% lighter than steel, allowing for easier on-site handling and lowered emissions during transportation. As PP-R is 100% recyclable, further environmental benefits can be realised.
Sustainability concerns go hand-in-hand with those around installation time and material use. Because PP-R eliminates expansion loops and reduces directional change bends used in steel networks, fitting is quicker, with less components required due to less joints. PP-R pipe’s lighter weight and the PE-Xa pipe’s flexibility also facilitates a quicker and more flexible installation.
In conclusion, the need to decarbonise means we must entertain innovative new heating technologies, including polymer district heating systems. By doing so, we can improve sustainability while also enjoying further benefits, such as ease-of-installation and lower operational costs.
For more information on district heating and PP-R pipework, visit www.rehau.uk/districtheating
Swegon - Visualising the invisible air quality challenge
We humans have to breathe air to survive. Oxygen-rich air is initially found outside, however, people work and live in buildings. Like our lungs, buildings need to be able to breathe to ensure fresh air comes in and dirty air escapes. In fact, some say we even spend 90% of our time indoors, so having a good indoor climate to live-in is vital for our health and wellbeing!
A recent study shows that between 30 and 40 percent of employees have symptoms like headache or attention problems at work. At the same time, we need to think more sustainable and decrease our carbon footprint. This is a challenge for the entire industry, affecting everything from product development to how we operate.
Human, building, planet
Swegon’s holistic approach to the ventilation challenge consists of three parts - Human, Building and Planet – and by addressing them together, we can move towards a solution.
1) The Human – meeting the basic health and wellbeing needs of the people living or working inside the buildings.
2) The Buildings - Customer adaptations and changes in usage over time puts high demand on the flexibility of the building services solutions. More recently IT security has also become an issue, as connectivity is sometimes applied in a patchwork fashion.
3) The Planet - buildings are responsible for 40 percent of the world’s CO2 emissions, both from the building materials and from the energy consumed over time. We as suppliers have a huge responsibility here and we need to make sure there is a low energy usage from our products and solutions.
It is imperative that we do not address these challenges one by one in sequence, but that we address them as parts of the same challenge, to ensure a healthy, economically viable and sustainable solution.
Stepping up to the challenge
So, how do we solve this? In short: with a system approach. Instead of looking at each product and service separately, we need to make sure it all works together to achieve a low lifecycle cost. By measuring and demand-controlling the indoor environment we can create a healthy indoor climate with the lowest possible energy consumption.
To do this we need better tools in our toolbox to interact with, and manage, the building. The data collected with connected devises enable us to create algorithms to optimize energy performance and indoor climate. An example is the Swegon WISE system, which has already been able to adjust the indoor climate to the actual need of the building at any given moment with optimized airflows. With a newly added feature – water optimization – data input from the room can be connected to the heating and cooling of the building, resulting in a further decrease in energy consumption of up to fifteen percent.
But this is not enough, we also need to get to the next level, beyond optimized products. We need to collect information from outside the system, such as weather predictions and cost of electricity. By combining this information with data from the products we can create smarter buildings and develop smarter products. For example, the new mobile device app Swegon Inside is enabling the customers to “see” and determine the quality of the indoor environment. This increases the knowledge and awareness of the surrounding indoor climate, insights which are fundamental if we want to drive change. Visualising the invisible is the key for the future.
To learn more about the challenges we face to solve the IEQ puzzle, join us for a seminar on “The Human, Building, Planet Challenge – IEQ in the built environment” on July 1st hosted for the CIBSE Technical Symposium.
Hamworthy Heating - On the pulse of time
Hamworthy Heating is this year’s Silver Sponsor for a second year in a row. For the company, the importance of working together to make a difference in the industry was one of the main motivators to support the event again
Sam Boshier, marketing manager for Hamworthy, commented, “Last year’s virtual event packed a lot into the two days, covering some very interesting topics from fake news to the importance of collaboration. We’re looking forward to being involved again and hearing the papers and case studies that have been submitted under this year’s topic of Engineering the built environment for a new 'normal'. What is the new normal? The pandemic has had an impact on everyone, and our buildings must adapt to the changing way we’re using them. Hearing from the presenters over the two days helps us as a manufacturer to improve our products and knowledge to support engineers and the built environment of the future.”
On the pulse of time
Hamworthy has been a long-term member of the CIBSE Patrons programme. Following its commitment, the trusted expert in heating is keen to be involved in such opportunities to exchange knowledge.
Miss Boshier added,
“We’re excited to be presenting our new Controls CPD as part of the CIBSE #GrowYourKnowledge webinar series. Controls are such a vital tool for making sure we reduce our energy consumption and only use what we need. In the webinar we’ll be cutting through the jargon that is often used when talking about controls and show you how to setup heating equipment for best efficiency, energy saving, and safety.”
Which topics are you most looking forward to over the two days? With so many topics it’s difficult to choose. But this one stood out for Hamworthy as a key supplier to heating and hot water refurbishments projects: Adaptation and refurbishment for improved, and healthier, built environments. We know that new buildings are more energy efficient, but 80% of buildings that will be standing in 2050 have already been built. This means decarbonisation of our existing stock needs to be a major priority. And this comes with its own unique challenges.