Spring Statement – New homes to be heated using low carbon sources from 2025

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Contact us on 01372 722277 for further information or a quotation.

Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels and that the UK will implement policies to increase the proportion of “green gas” within its gas grid to support this aim.

This follows the publication of the Committee on Climate Change’s (CCC) warning that energy-inefficient and high-carbon housing is jeopardising the UK’s chances of meeting its carbon budgets.

Evinox believes this offers an excellent opportunity for the heat network industry to drive the design of new systems using green energy sources, such as heat pumps or solar thermal, and to lower heat losses for the network using smarter design. An additional benefit for existing heat networks is the ability to swap the primary energy source for greener alternatives in the future, which allows for new technologies to be easily integrated.

Hammond states “As with the challenge of adapting to the digital age, the challenge of shaping a carbon-neutral economy of the future is pressing,”

“We must apply the creativity of the marketplace to one of the most complex problems of our time – climate change – and build sustainability into the heart of our economic model.”

This also follows last year’s announcement that Government intends to regulate heat networks, something Evinox is firmly in favour of. Regulation of heat networks is key for meeting these growth targets and Evinox continue to work with the industry to help shape these regulations.

Spring Statement – New homes to be heated using low carbon sources from 2025

Spring Statement – New homes to be heated using low carbon sources from 2025

Communal and District Heating News Regulations Technical
Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels.
Read More
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Hot Water Response Time and Heat Network Efficiency

Hot Water Response Time and Heat Network Efficiency

Blog Heat Interface Units Technical
Read our latest blog, which discusses the design trade-offs between hot water response and energy efficiency in heat networks.
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Discover how Evinox Energy can deliver the best solution for your next new build or refurbishment heat network project

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Evinox Unit’s Perfect Fit at Canary Wharf’s New District, Wood Wharf

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Contact us on 01372 722277 for further information or a quotation.

A new urban district is being created in London’s Canary Wharf, which when complete will feature up to 3,600 new homes, a GP’s surgery, a two form primary school for 420 children, 490,000sq ft of retail space and eight acres of public spaces squares and parks. The development, called Wood Wharf, has been designed to provide a new residential led, mixed use, waterside community and is expected to be completed by 2023.

The scheme was approved by Tower Hamlets Council in 2014, which described its design as “innovative”. In recognition of this innovation, Wood Wharf won the Tall Buildings category of the MIPIM Architectural Review Future Project Awards in 2014.

Working with the developer, Canary Wharf Group (CWG), in combination with SES Engineering Services, Emico and Haydon Mechanical & Electrical contractors, Evinox Energy supplied heating and cooling interface units for 1330 apartments for the first phases of this development, with more to follow for the remaining phases.

Homes are all connected to a district heating network, with each apartment featuring a ModuSat XR-ECO Twin Plate heat interface unit for the supply of heating and hot water and a ModuSat Single Plate interface unit to provide cooling.

Wood Wharf Image

CGI of Canary Wharf’s new district, Wood Wharf


Tested by BSRIA to project design parameters

Interface units were tested by BSRIA as a requirement of this project, something Evinox were happy to undertake, confident the first-class product manufacturing and performance would deliver the required results.

Peter Linehan, Evinox Technical Sales Manager comments, “The main objective of the testing was to confirm the performance of the heating and cooling units under the specific design parameters of Wood Wharf phases A2/A3, E1/E2. The method statement was based upon three different sources; BESA UK Standard for Heat Interface Units Technical Specification, BSRIA BTS 2/2015 Test Method for Heat Interface Units and recommendations from the clients commissioning company.”

Peter continued, “Evinox’s ModuSat XR-ECO TP HIU’s and ModuSat SP CIU’s were submitted, with a total of 8 units tested at the BSRIA Test House. These included each building’s most common HIU/CIU model and high load units. The interface units achieved excellent results, performing to the project requirements, which culminated in an order for the first 5 phases of the Wood Wharf development.”


Flexible manufacturing capabilities

In addition to the efficient performance of the ModuSat units, Evinox equipment was also chosen due to the flexibility of manufacturing and short delivery timescales. “On-time” delivery schedules were critical for this project, as some of the equipment was being built into prefabricated pods by a third party prior to delivery to site.

Our range of heat interface units are designed and developed internally by technical engineers to UK standards, and built in Evinox’s own production facility in Brasov Romania by partner Romradiatoare, using lean manufacturing principles. Working closely with component suppliers enables us to deliver bespoke units, built to project specific requirements, in a timely manner.


World-leading components

One of the key components used in every ModuSat HIU, is the high efficiency plate heat exchanger from SWEP, who are a world-leading supplier of brazed plate heat exchangers for HVAC and industrial applications. Evinox’s ModuSat XR-ECO HIU delivers impressive, ultra-low DHW return temperatures to the primary network by incorporating SWEP high efficiency domestic hot water plate heat exchangers with volumetrics that encourage turbulent flow. This contributes to excellent annual Volume Weighted Return Temperatures and system operating efficiency.

Spring Statement – New homes to be heated using low carbon sources from 2025

Spring Statement – New homes to be heated using low carbon sources from 2025

Communal and District Heating News Regulations Technical
Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels.
Read More
1 2 3 35
Hot Water Response Time and Heat Network Efficiency

Hot Water Response Time and Heat Network Efficiency

Blog Heat Interface Units Technical
Read our latest blog, which discusses the design trade-offs between hot water response and energy efficiency in heat networks.
Read More
1 2 3

Discover how Evinox Energy can deliver the best solution for your next new build or refurbishment heat network project

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Changes to Hot Water Services in NHBC Standards for 2019

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Contact us on 01372 722277 for further information or a quotation.

NHBC is the UK’s leading warranty and insurance provider for new homes, setting standards for registered builders and working to help improve the construction quality of homes built.

They recently announced the launch of their 2019 Standards, which will become effective from 1st January 2019. The standards apply to all properties with foundations laid on or after that date.

Evinox are happy to see some updates to ‘Hot water services’ in the new standards, where changes have been made to some of the flow rates and supply temperatures at the outlets. For example, the supply temperature at the kitchen sink has been reduced from the previous 60C to 55C, which is in line with the delivery temperature that was selected for the majority of Heat Networks, during the last year.

 

NHBC Standards 2019 Table 3

 

Helen Gibbons, Evinox Technical and Design Manager, Comments, “This change to the outlet temperature is a very positive development as it will enable district and communal heating system flow temperatures to be reduced, something which is especially important for the growth of 4th Generation Heat Networks in the UK.

In addition, the lowered DHW temperature combined with the new table in the NHBC standard for simultaneous hot water use, will give design engineers the confidence to reduce the kW demand for individual properties, something which will improve both efficiency and cost of UK Heat Networks.”

Helen continued, “whilst we are very happy to see that the required temperature from the kitchen outlet has been lowered to 55C for 2019, we do hope to see this further reduced to 50C for heat network developments using instantaneous DHW heat interface units in the near future.”

You can find the full Standard by visiting the NHBC website

Spring Statement – New homes to be heated using low carbon sources from 2025

Spring Statement – New homes to be heated using low carbon sources from 2025

Communal and District Heating News Regulations Technical
Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels.
Read More
1 2 3 35
Hot Water Response Time and Heat Network Efficiency

Hot Water Response Time and Heat Network Efficiency

Blog Heat Interface Units Technical
Read our latest blog, which discusses the design trade-offs between hot water response and energy efficiency in heat networks.
Read More
1 2 3

Discover how Evinox Energy can deliver the best solution for your next new build or refurbishment heat network project

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Remote Warranty Validation and Service and Maintenance for HIUs

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Contact us on 01372 722277 for further information or a quotation.

For any residential building project, time saved on site is hugely beneficial for developers, contractors and housing associations alike, helping to reduce project costs and enabling residents to occupy properties as quickly as possible. With this in mind, we have introduced remote warranty validation for our ModuSat heat interface units (HIUs), which can significantly reduce the cost of commissioning and time spent on site by engineers manually checking and adjusting settings.

Many other heat interface units for communal and district heating developments require an engineer to physically attend site to set-up every individual unit manually, adding time and cost to the project. Our electronically controlled ModuSat HIU’s feature SmartTalk communication technology and can be connected over the internet to remote servers, enabling us to check the operation of each unit remotely and adjust settings where required.

Once ModuSat units are installed and ready to be commissioned the following quick and simple process takes place –

  • Installer Registers ModuSat Units Using Evinox’s Online Registration Portal
  • Evinox Check the Operation of Each ModuSat Unit remotely
  • Evinox Visit site to inspect a sample of units (Around 10% of the total units)
  • Evinox will then certify the units and issue certificates
  • The Warranty period begins

The benefits don’t just end there! During the aftercare period, following practical completion, Our SmartTalk remote communication system enables checks to be made and faults to be diagnosed away from site. Just think about the costs incurred every time an engineer is called to site, well these can be avoided using our communication system to adjust settings remotely.Remote Communication for ModuSat HIUs

It is also important to factor in on-going servicing and maintenance, which maximises the life of the Heat Interface Unit and ensures optimum performance of both the HIU’s and also the wider heat network. Our SmartTalk® communication system allows for scheduled maintenance checks to take place remotely over the internet.  The system in each apartment can be fully controlled remotely, including timings and settings, with remote diagnostic capability and client support. This can avoid unnecessary call-outs as a result of user error. Fault alarms can also be checked by testing the operation of components.

We offer after-care service and maintenance plans that are available with one or two-year contracts providing flexibility, and additionally, combined packages for energy billing and maintenance, all under one roof and with discounts available.

Spring Statement – New homes to be heated using low carbon sources from 2025

Spring Statement – New homes to be heated using low carbon sources from 2025

Communal and District Heating News Regulations Technical
Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels.
Read More
1 2 3 35
Hot Water Response Time and Heat Network Efficiency

Hot Water Response Time and Heat Network Efficiency

Blog Heat Interface Units Technical
Read our latest blog, which discusses the design trade-offs between hot water response and energy efficiency in heat networks.
Read More
1 2 3

Discover how Evinox Energy can deliver the best solution for your next new build or refurbishment heat network project

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Hot Water Response Time and Heat Network Efficiency

Evinox-Hot Water and duck

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Contact us on 01372 722277 for further information or a quotation.

As the old saying goes – you can’t have it all. When it comes to heat networks, there is a distinct balancing act between heat network efficiency and hot water response time.

In this blog, Helen Gibbons, Technical and Design Manager at Evinox will discuss the trade-offs between hot water response and efficiency in heat networks.

 

VWART vs. DHW response

Introduced in 2016, the BESA (British Engineering Services Association) UK Standard for HIUs was launched to help designers and specifiers evaluate the performance of a particular unit on their network. To date, of the 7 electronic units with published test results, a trend can be seen where the HIU achieving the lowest VWART delivers the slowest DHW response time, and vice versa. Most units tested achieve balanced results and end up somewhere in the middle for both tests.

BESA RESULTS GRAPHS

The charts shown above display a VWART figure and DHW response time for each electronically controlled HIU that has been through the BESA test (I haven’t included results for mechanical HIUs as they are not able to control the keep warm functionality). These results clearly show a correlation between a low VWART figure and slow DHW response. HIU manufacturers who have put their unit forward for this test have made a choice – what do we think is more important, VWART or DHW response time?

The manufacturer with the impressive VWART figure of 28.0 °C has achieved this partly by allowing their DHW response time to increase to 12 seconds for the high temperature test (and 14 seconds, close to the required limit of 15, in the low temperature test). At the same time, the manufacturer with the fastest DHW response time, which is 6 seconds, has clearly achieved this at the expense of the VWART – achieving 38.4 °C.

 

What is keep warm functionality and what role does it play?

One of the key impacts on the overall VWART figure is the use and control of the “Keep Warm” facility, which is designed to keep the hot water plate heat exchanger warm continuously so that the HIU’s can provide a fast response as soon as there is demand for domestic hot water. This function also has the added benefit of keeping the risers and laterals warm, although additional controlled bypass valves are sometimes required, for example at the top of the riser or at the end of laterals.

(Check out my previous blog for more information about Keep-warm)

Whilst the VWART figure clearly reflects the efficiency of the plate heat exchangers and valves used in the unit, it also shows that improvements can be made by adjusting the keep warm strategy and allowing the DHW response time to increase. It’s obvious when you think about it, if less power is used to keep the plates warm, it will then take longer to receive hot water.

With the new generation of electronically controlled smart HIUs on the market, which feature self-learning, there are a number of settings that can be put in place for the keep-warm functionality, to help provide a fast DHW response with a low VWART. Take our ModuSat XR as an example, the self-learning functionality means the unit can learn what time you get up every morning and make the plate hot and ready for you by that time. Even if this might not show in BESA test results, in real life terms this will further reduce the return temperature.

Additionally, with a Smart HIU the network operator is able to decide the best solution for their specific network and make adjustments to the settings remotely. Is it DHW response time for the residents or the overall efficiency of the heat network or an agreed compromise for both?

 

Legionella and DHW response

But by how much can you delay the DHW response time without getting into bother? Is the DHW response time a question of convenience and comfort, or are there other aspects at play?

These questions go hand in hand with what I discussed in my previous blog post about timing the keep warm function, where a large energy saving can be made if the system is designed in a way which lets the keep warm function switch off during parts of the day.

One of the arguments out there against a delayed DHW response time, is the possibility of the hot water taking longer than 60 seconds to reach the outlets. The Hot Water Association even goes as far in their Design Guide for Stored Water Solutions [1] as to boldly state that the keep warm function is required for twin plate HIUs to meet requirements of legionella and water regulations, which is simply not true.

This all stems from HSE’s advice on Legionnaires disease, where in HSG274 Part 2 it states that the traditional strategy for reducing risk of legionnaire’s disease, is to store water at 60°C or above, and for this water to be distributed so that it reaches the outlet at 50°C within one minute. It is important to note that the same document classes instantaneous heaters as low-risk systems.

The same advice is replicated in BSRIA’s Legionnaires disease O&M log book, which suggests that hot water should reach 50°C within one minute, but class instantaneous water heaters as an alternative system presenting minimum risk from legionella.

BSRIA Legionnaires disease O&M log book

This advice is replicated in a number of other documents, all referencing back to HSE 274 Part 2.

The above table from BSRIA makes it clear that the “50°C within 60 seconds” school of thought stem from advice based on stored water, but as there is next to no stored water in a twin plate HIU, the risk of legionella is minimised.

We also have the well-respected German Standard DVGW W 551 (Drinking water heating and drinking water piping systems; technical measures to reduce Legionella growth) which states that if controlled properly, a system with a total volume (from hot water production to end use) of less than 3 litres can eliminate the risk of Legionella.

Standards and regulations aside, is there actually a risk of legionella if the DHW takes longer than 1 minute to reach the outlet? From what I have found there is and there isn’t, but the DHW temperature set point at the HIU makes no odds.

At 60°C, it takes 25 minutes to kill the legionella bacteria [1].  If we take this information and think about cold water being heated up to 50°C in the plate heat exchanger of the HIU. The water will be heated for a fraction of a second, nowhere near enough time to kill any of the bacteria present in the water.

This is backed up by the following graph illustrating how long it takes to decrease or increase the growth of legionella bacteria at different temperatures [2]:

Growth of legionella bacteria Graph

The y-axis is showing the number of bacteria colonies per ml H2O and the x-axis is showing hours lapsed. This graph shows that after one hour at 50°C, the bacteria has reduced by 60%, but that during the small amount of time the water is heated to 50°C in the PHE, the level of bacteria is unaffected.

What about if the water is heated to 50°C and kept at 50°C during the one minute it takes for it to get to the tap? Nope, it still doesn’t look like one minute at 50°C will be able to kill much of the bacteria that would potentially be present in the water.

The conclusions I draw from this information are that getting the water to the tap at 50°C within 1 minute has no effect on the legionella risk when it comes to instantaneous twin plate HIUs. The risk is where the water is stored, ie. in the cold water booster tank and the cold water distribution pipework. This is where there is a risk of the legionella bacteria multiplying if the temperature of the cold water is too high, and if the bacteria has been given the chance to grow in the cold water pipework. Heating it to 50°C or even 60°C in an instantaneous water heater will not kill it or even noticeably reduce the levels.

Despite this information, I can still understand if system designers would like to stick to the 50°C within 1 minute rule in the absence of any firm advice regarding instantaneous heaters. Even BS 8558:2015 quotes the 50°C within one minute rule, but again references back to HSG274 Part 2. A discussion needs to be had with HSE to see if this piece of advice can be rewritten to clarify that this rule should not apply to instantaneous heaters.

If legislation stipulates a high DHW temperature with a very fast DHW response time, this will lead to the continuation of unnecessarily oversizing heat networks under a false pretence that this somehow protects the end user from contracting Legionnaire’s disease.

There is of course still the comfort argument to be had, but that’s for another day.

 

Hot water return and heat network efficiency

In line with the above, we often see projects where a specific domestic hot water return temperature is detailed in the specification for instantaneous twin plate HIU’s. When we see this, it is important to have a discussion with the client to understand the reasons behind the required temperature and explain how this might affect the heat network efficiencies.

As with the keep warm facility, the DHW return will increase convenience for the resident but will come at an expense of the heat network. The return temperature of the primaries cannot physically be lower than what they are cooling down against, and if they are constantly cooling down against a hot water return of 50°C, the primary return will always be above 50°C in this mode.

The above will also mean that the HIU will constantly be bypassing primary water, so both the total volume of water, as well as return temperature, will increase.

 

Alternative designs that offer a happy medium

When I said earlier that you can’t have it all – this is of course not true. There are a couple of ways in which you can have a fast DHW response time which will not come at the expense of the heat network efficiency. Solutions we recommend include the following;

  • Trace heating of the hot water pipework. If a trace heating cable is placed on the pipework underneath any lagging, you will still get the fast delivery of hot water. And as the trace heating is only used to maintain the temperature of the water in the pipe, rather than heating it up from cold, the energy consumption from applying this is low.
  • Reduce the size of your hot water pipework. Let’s say the pipework required from the HIU to your hot water outlet is 6 meters. If you use 22mm copper to deliver this water, and the required hot water flow rate is 0.10 l/s, the velocity within the pipework will be approximately 0.31 m/s and it will take the water almost 20 seconds to get to the outlet. Reduce the pipework dimension to 15mm and the delivery time is more than halved to 9 seconds. And if you are able to use 10mm pipework the velocity increase to 1.64 m/s with a delivery time of only 4 seconds! This means that even if the HIU takes 55 seconds to get the hot water up to 50°C, you are still within the golden minute.

If this is not possible, an alternative to using small dimension pipework is to install a potable water manifold at the HIU, and to have a single pipe serving each outlet.

 

Conclusion

In almost all cases – fast hot water response time will come at the expense of the heat network efficiency. As an industry, it should be our priority to make these networks as efficient as possible to avoid getting negative press and secure the position of heat networks in the UK infrastructure. It is the price per kWh and the carbon emissions that will get measured at the end of the day – not how long people have to wait to have a shower, especially not when it is a question of seconds.

In high end developments, where comfort and convenience are especially critical, the alternative design solutions should be used, i.e. trace heating or small-bore pipework. As long as there are ways around this, let’s allow our systems and HIU’s to perform as efficiently as possible.

But most importantly of all, let the operator of the heat network decide what they want to do, after all, they will know their system and residents better than any of us. Is efficiency and cost important? Is fast hot water response important? As long as we give the operator the information and benefits of different options, why not let them decide? With a smart-HIU they can even try different options out over time, until they find the ultimate strategy for their building.

Spring Statement – New homes to be heated using low carbon sources from 2025

Spring Statement – New homes to be heated using low carbon sources from 2025

Communal and District Heating News Regulations Technical
Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels.
Read More
1 2 3 35
Hot Water Response Time and Heat Network Efficiency

Hot Water Response Time and Heat Network Efficiency

Blog Heat Interface Units Technical
Read our latest blog, which discusses the design trade-offs between hot water response and energy efficiency in heat networks.
Read More
1 2 3

Discover how Evinox Energy can deliver the best solution for your next new build or refurbishment heat network project

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Fresh New Website Showcases Our Heat Network Products and Services

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Contact us on 01372 722277 for further information or a quotation.

We are delighted to announce the launch of our new company website, which features a fresh look and feel and user-friendly navigation, enabling users to browse through our extensive range of heat network products and services with ease. These include a range of smart heat interface units (HIUs) and comprehensive support services including metering, billing, revenue management and service and maintenance.

Delivering a fully responsive experience, the new website gives users a seamless transition from desktop to mobile browsing and has been designed to provide heat network information for Housing Developers, M&E Consultants, Housing Associations and Building Managers, covering all stages of a communal or district heating project.

Evinox Heat Network Solutions Website Office Desk

Emma Alexander, Marketing Manager at Evinox Energy, says“We are really excited about the launch of our new site, which we’ve packed with useful heat network information, including articles, case studies, best practice and regulation advice, alongside technical information about our ModuSat® Smart HIU range and metering, billing and maintenance support services. We love the new look and feel of the site, and see it as the cornerstone of our online marketing strategy, aligning our digital platform much more closely to our brand and product and service offerings,”

Let’s Talk About Smart HIU’s

The new Smart Heat Interface Unit Hub on the Evinox website features plenty of technical content and useful information and includes everything you need to know about Evinox’s ModuSat® range of HIUs. The hub also covers topics such as the UK BESA HIU test standard, designing for energy efficient networks and the benefits of electronic control. It even features an online tool for selecting Heat Interface Units based on your project parameters and provides calculations for the whole network. Users can also request one of Evinox’s CIBSE accredited CPD seminars and download the Heat Network Design Guide via the website.

Find Out How Evinox Can Help with Metering and Billing for Your Heat Network

The website walks you through all the requirements of a successful metering and billing system for a heat network development. This includes information about the typical network set-up, which domestic and commercial meters might be required, credit billing services, debt free Pay-as-you-go technology and guidance about how to comply with the Heat Network (Metering & Billing) Regulations 2014.

Service & Maintenance Support for Heat Networks

Knowing how vital the support services can be for the operation the heat network and HIUs alike, Evinox’s new website provides lots of useful information for housing developers and building managers. Find out more about our internet based remote Service and Maintenance for HIU’s, enhanced warranty cover, plant room maintenance and combined plans for billing and service where we offer very competitive discounted rates for both in one package.

Emma Alexander continued“As we strive to improve every aspect of Evinox’s on and offline presence, flagship projects such as this demonstrate our commitment to excellence to our customers and partners. I’m extremely excited to be involved in the continued evolution of Evinox Energy and look forward to sharing what we’ve got in the pipeline over the coming months”.

Spring Statement – New homes to be heated using low carbon sources from 2025

Spring Statement – New homes to be heated using low carbon sources from 2025

Communal and District Heating News Regulations Technical
Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels.
Read More
1 2 3 35
Hot Water Response Time and Heat Network Efficiency

Hot Water Response Time and Heat Network Efficiency

Blog Heat Interface Units Technical
Read our latest blog, which discusses the design trade-offs between hot water response and energy efficiency in heat networks.
Read More
1 2 3

Discover how Evinox Energy can deliver the best solution for your next new build or refurbishment heat network project

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New Online Tool Helps Designers with HIU Specification

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Contact us on 01372 722277 for further information or a quotation.

Evinox are excited to announce the launch of the ModuSat® Heat Interface Unit Online Selector. Available via the Evinox Energy website, this intuitive tool recommends the ideal HIU(s) for a district or communal heat network development, based on project parameters entered by the user

Screen shot of selector toolWith over 15 years of experience in the design and manufacture of interface units for heat network systems, Evinox created the Selector with M&E consultants in mind, aiming to provide a tool that is easy to use, and can help with sizing and selection whilst saving time for the specifier.

Helen Gibbons, Evinox Technical and Design Manager comments – “This unique new tool is an extension of the Evinox Heat Network Design Guide that is used by many M&E consultants in the UK. It draws on Evinox’s experience sizing HIU’s for numerous communal heating projects, and also recommendations from the Swedish District Heating Association Technical Provisions F:101, Danish Standard 439 and the CIBSE CP1 – Heat Networks: Code of Practice for the UK “

Helen continues “In addition to the heat interface unit sizing and selection functionality, our new tool provides heating and hot water technical performance information specific to the users’ project, complete with Low Temperature Hot Water (LTHW) calculations for the whole heat network, which can act as a useful guide for the design and specification process.”

A well as all the functionality detailed, the user can also save unit selections and calculations for each project and come back at any time to access or edit them or to create a new selection, making this a really useful resource for consultants.

Find out how the ModuSat® Selector can help with the specification of heat interface units and try it out by visiting the Selector here.

Spring Statement – New homes to be heated using low carbon sources from 2025

Spring Statement – New homes to be heated using low carbon sources from 2025

Communal and District Heating News Regulations Technical
Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels.
Read More
1 2 3 35
Hot Water Response Time and Heat Network Efficiency

Hot Water Response Time and Heat Network Efficiency

Blog Heat Interface Units Technical
Read our latest blog, which discusses the design trade-offs between hot water response and energy efficiency in heat networks.
Read More
1 2 3

Discover how Evinox Energy can deliver the best solution for your next new build or refurbishment heat network project

Evinox Contact Us Image

HIU Keep Warm – What’s the Best Approach?

Evinox-Hot Water and duck

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Contact us on 01372 722277 for further information or a quotation.

If you have an interest in Heat Network design or are involved in the specification of Heat Interface Units (HIUs), you will no doubt be aware of the new BESA (British Engineering Services Association) UK Standard for HIUs, launched in late 2016.

This new standard is regarded as a really important step towards improving the overall performance of British district heating schemes, and its key objective is to enable the performance of different HIUs to be evaluated within the context of typical UK operating conditions. This will enable heat network developers to consider the performance of specific HIUs against design requirements.

The main outcome from the BESA test standard is a Volume Weighted Average Return Temperature – or “VWART” for each HIU at standardised high temperature and low temperature network conditions.

A lower overall VWART represents a lower average annual return temperature from the HIU to the primary network and therefore a better performing HIU. The example below shows published BESA VWART results for our ModuSat® XR-ECO at High Temperature Test Conditions –

 

Keep Warm BlogToday I want to focus on the “Keep Warm” function, looking at the different approaches and how best to balance the supply of hot water with the overall efficiency of the network.

So what role does the Keep Warm Play?

One of the key impacts on the overall VWART figure is the use and control of the “Keep Warm” facility, which is designed to keep the hot water plate heat exchanger warm continuously so that the HIU’s can provide a fast response as soon as there is demand for domestic hot water. This function also has the added benefit of keeping the risers and laterals warm, although additional controlled bypass valves are sometimes required, for example at the top of the riser or at the end of laterals.

For the BESA test regime, the Keep Warm VWART figure is calculated using a weighted average that assumes Keep Warm is switched ON for an average of 90% of the year (i.e., constantly available while the HIU is not producing space heating or hot water).  And while the Keep Warm facility should only ever bypass a small volume of water per hour, the proportionately high number of annual hours that a Keep Warm bypass might be left “on” for can add up to a significant amount of warm water being bypassed back to the network over the course of the year, wasting energy, raising the primary return temperature and reducing the delta T, as illustrated in the table below:

KWF Table 1

As can be seen, despite the Keep Warm being temperature controlled (in this case), this facility is still potentially responsible for over a third of the annual volume of water by passed back to the primary network.

So, what’s the best approach?

You will find that different HIU manufacturers approach “keep warm” in different ways, typically we see the following for UK heat interface units –

KWF Table 2

By far the most efficient and effective solution, is to provide both time and temperature control over this function, by additionally allowing the keep warm to be timed, it can be de-activated during times of low demand (eg middle of the night), something which is only possible with electronically controlled HIU’s. With a growing understanding in society of the need to be more energy efficient, residents are likely to find it acceptable having to wait a little longer for their hot water at 3am, especially if the cost and energy saving benefits are explained to them. The latest Evinox ModuSat XR models allow this control to be managed either by individual residents themselves; or managed globally across the network by the operator, as the Keep Warm time and temperature settings can be remotely adjusted.

This means that real life average annual return temperatures can be further reduced, with a suitable balance struck between the speed of DHW delivery for the home owner and the overall network efficiency requirements of the operator.

For example, we have calculated that the impact of restricting the operation of the Keep Warm facility to 8 hours per day, can result in a 23% reduction in water bypassed back to the primary network.  Based on the performance of the Evinox ModuSat XR HIU, this would improve the (already impressive) overall VWART figure by a further 7°C – giving an annual Volume Weighted Average Return Temperature of 26°C!

But is there an increased risk of Legionella?

HSE guidelines state that the hot water should reach the outlet at 50°C within one minute. Does this mean that there is an increased risk of Legionnaires disease if the keep warm function is turned off causing a delay in the hot water to come through? No, it doesn’t!

First of all, the “50°C within 1 minute” guideline is there specifically for hot water storage. As there is no storage of hot water in an instantaneous heat interface unit, the legionella risk is virtually eliminated. Additionally, when the keep warm function is turned off in several properties across the network, this will stop unnecessary circulation through laterals which in turn will help prevent overheating of ducts. Overheating of ducts can cause the temperature of the incoming cold water to rise above 20°C, favourable conditions for legionella growth. I will be discussing this in more detail in a future blog.

So, as you can see, it’s important to consider the HIU Keep Warm strategy when designing your next communal or district heating project. Decisions made at the design stage can help to ensure you provide the best system for residents, whilst also maintaining optimum network efficiency.

Helen Gibbons – Design & Technical Manager Evinox Energy Ltd.

Find out more about Evinox’s ModuSat XR range of electronic HIU’s with full time and temperature control

Spring Statement – New homes to be heated using low carbon sources from 2025

Spring Statement – New homes to be heated using low carbon sources from 2025

Communal and District Heating News Regulations Technical
Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels.
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Hot Water Response Time and Heat Network Efficiency

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Discover how Evinox Energy can deliver the best solution for your next new build or refurbishment heat network project

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Evinox team of CIBSE Certified Heat Network Consultants expands

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Contact us on 01372 722277 for further information or a quotation.

Evinox has added to its CIBSE certified Technical and Design team, with Design Engineer Arturs Kokins becoming the latest to successfully complete the CIBSE Heat Networks Code of Practice course, passing his final exam with flying colours.

The CIBSE Heat Network qualification is recognised across the industry and covers a broad spectrum of considerations for communal and district heating systems, demonstrating the depth of knowledge Evinox can offer to their customers in the design of heat network systems.

Arturs CIBSE Image

 

Arturs originally joined Evinox in early 2017 as a Graduate Engineer, with an MEng (Hons) Mechanical Engineering degree, and has since developed his skills and gained valuable experience working on a number of key projects. These include managing bespoke testing with BSRIA (Building Services Research and Information Association) for a large development in London where Evinox is supplying heating and cooling units. He was also involved in Evinox successfully completing testing under the new BESA (British Engineering Services Association) UK Standard for Heat Interface Units, for which the Evinox ModuSat (XR) HIU achieved excellent results and is currently one of only five manufactures to have officially published its results on the BESA website, something the company is very proud of.

“Arturs is a perfect example of what can be achieved by investing in people and promoting their growth within a business,” comments Helen Gibbons, Evinox Technical and Design Manager. “He is a highly valued member of the team at Evinox, and we are delighted to employ a Design Engineer of Arturs calibre.”

Evinox offers developers, consultants and specifiers a broad range of design support services for district and communal heating projects, including HIU sizing and selection; hydraulic system guidance and advice; and complete plant room system and distribution pipework design, where required.

Please contact Evinox on 01372 722277 or complete the contact form to find out more about our Design Services or BESA tested Heat Interface Unit range.

Spring Statement – New homes to be heated using low carbon sources from 2025

Spring Statement – New homes to be heated using low carbon sources from 2025

Communal and District Heating News Regulations Technical
Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels.
Read More
1 2 3 35
Hot Water Response Time and Heat Network Efficiency

Hot Water Response Time and Heat Network Efficiency

Blog Heat Interface Units Technical
Read our latest blog, which discusses the design trade-offs between hot water response and energy efficiency in heat networks.
Read More
1 2 3

Discover how Evinox Energy can deliver the best solution for your next new build or refurbishment heat network project

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A New Captain Takes the Helm

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Contact us on 01372 722277 for further information or a quotation.

Evinox are thrilled to announce that Terry Mahoney has taken the helm as its new Managing Director. Terry originally joined Evinox in 2010 and through his most recent role as Operations Director has been pivotal to much of the company’s recent success, including the delivery and ongoing support of key projects – such as Battersea Power Station; and the evolution of Evinox’s manufacturing capability.

Terry said of his new position “I’m delighted and flattered to be appointed as Managing Director at Evinox. This is an exciting time for the business, with planning regulations and government policy continuing to support the deployment of district and communal heating, the market continues to thrive and evolve. Evinox has seen a strong growth in sales over the past 12 months, and with product innovation and development at the forefront of the company strategy this is only set to increase”.

Terry Mahoney MD Company Image

He continued “As an established, marketing leading heat interface unit manufacturer, Evinox offers innovative products that are built with quality components and assembled to world class manufacturing standards. This has been confirmed by the Impressive efficiency performance achieved by the Evinox ModuSat heat interface unit, which was tested to the UK standard from BESA”.

The Building Engineering Services Association (BESA) UK test standard for heat interface units (HIUs) was recently introduced to enable designers and specifiers to evaluate the performance of a HIU on their network. Currently, only a handful of manufacturers have published results for the HIU test regime, with Evinox being one of the first to undertake the testing process. The results achieved provide a clear, independently verified confirmation that the Evinox ModuSat® XR HIU range delivers outstanding heating and hot water efficiency performance for modern heat networks – something the team at Evinox are very proud of.

The strong growth in sales reported, can be clearly demonstrated by the calibre of clients and projects that Evinox are working with. Evinox is already in the process of delivering over 1700 heating and cooling interface units for projects in Canary Wharf and over 1000 units for the same client on a prestigious project on the South Bank in central London.  At the same time, the company has also been successful in securing orders for over 700 heat interface units on the latest phase of the London City Island development in Greenwich. In addition to this, Evinox’s metering and billing services continue to grow, with contracts for hundreds of heat network schemes for both private and social housing across the UK. This includes the provision of bills for over 10,000 customers each year, and many, many more using the Evinox PaySmart pre-payment system.

Mahoney believes that it is a combination of the comprehensive product range and support services that Evinox offers, with the dedication of the Evinox team and keeping ahead of evolving industry standards that has spurred on the company’s recent success. The ability to offer options for heating and cooling, integrated energy display solutions and billing-ready options set Evinox HIU’s apart from others in the market.

Terry summarised by saying, “I’m an advocate of the “Under one roof” business model, which allows Evinox to combine first class product supply, flexible metering and billing solutions, and service and maintenance support – making us stand out from the crowd!”

Contact Evinox for further Information about our products and services, or a Quotation for your next heat network project.

Spring Statement – New homes to be heated using low carbon sources from 2025

Spring Statement – New homes to be heated using low carbon sources from 2025

Communal and District Heating News Regulations Technical
Evinox welcomes the Chancellors announcement in his spring statement (13th March 2019) that all new homes built from 2025 will be required to be heated by systems free from fossil fuels.
Read More
1 2 3 35
Hot Water Response Time and Heat Network Efficiency

Hot Water Response Time and Heat Network Efficiency

Blog Heat Interface Units Technical
Read our latest blog, which discusses the design trade-offs between hot water response and energy efficiency in heat networks.
Read More
1 2 3

Discover how Evinox Energy can deliver the best solution for your next new build or refurbishment heat network project

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