building. climate. excellence.
building. climate. excellence.
A2RXE HIU’s are for use where instantaneous hot water preparation is required combined with space heating output from one unit
The HIU is connected to the primary heat network via two pipes. When supplying Domestic Hot Water (DHW) the unit configures itself to deliver 100% DHW. Once the demand ends, the HIU moves into it’s usual state of supplying the space heating requirement. The HIU can also be set to a range of operating conditions. The DHW output can be set to different temperatures and volumes depending on the design brief. Similarly, the space heating temperature can be set permitting the unit to supply an underfloor heating installation.
The HIU A2RXE dual plate is used to provide domestic hot water and space heating in residences connected to a district heating system.
A Primary flow
B Primary return
C Cold water mains
D Domestic hot water (DHW)
E Secondary flow (Space heating)
F Secondary return (Space heating)
G Over pressure relief pipe
H Hot water return (optional, not illustrated)
* not visible
The BESA test results independently and clearly show that the HIU A2RXE dual plate is one of the best choices of HIU at this time. With superbly stable controls, return temperatures as low as physically possible, passing all the requirements in the test regime, and with VWART figures of: 31,4 - 15,6 - 31,5 and 16,4 the HIU A2RXE dual plate proves to be on the cutting edge of HIU technology. The Dual Plate is extremely compact and offers regular auto pasteurisation of the hot water side. With its fast, proven and fully configurable electronic controls, it is capable of feeding radiator and UFH systems with best-in-class efficiency and ultimate comfort. Read also the full test report.
BESA stands for Building Engineering Services Association. The BESA is the UK's leading trade organisation for building engineering services contractors – representing the interests of firms active in the design, installation, commissioning, maintenance, control and management of engineering systems and services in buildings.
Established as part of a UK government research project into heat network efficiency, the standard was, and continues to be, developed under the auspices of a steering group of industry experts.
"The BESA test is a test that measures typical performance of an HIU and the key metric coming out of each test is the VWART (Volume Weighed Average Return Temperature) value of a unit. The lower this value is, the more efficient a unit is."
The UK/BESA test standard for Heat Interface Units, developed to assess UK heat network operating parameters, is regarded as an important step towards improving the overall performance of British district heating schemes. It follows the first step made by Fairheat in 2016, towards improved network efficiency. An efficient HIU in a properly designed heat network can reach much higher efficiencies than current/typical DH systems in the UK are achieving.
The BESA test is a test that measures typical performance of an HIU and the key metric coming out of each test is the VWART (Volume Weighed Average Return Temperature) value of a unit. The lower this value is, the more efficient a unit is.
Main purpose of the BESA HIU testing regime is to raise minimum standards within the market (“bring the bottom up”), with an assessment of comparative performance in ‘standard’ conditions. A unit that has passed the BESA test is deemed to be ‘fit for purpose’.
In the current situation, an end customer might be faced with a different unit from the one specified as cost savings could be made during construction. With the current (at this time still optional) BESA regime available, such swaps, which are most of the time detrimental to system performance, comfort and efficiency should become a thing of the past. We believe that firm standards and metrics should become mandatory in the future to ensure the newly installed heat networks to offer the best comfort and efficiency to the end customers.
At the outset there should be reporting of performance, moving to minimum standards that must be met (pass/fail), with a raising of the bar and a progression to grading (e.g. A-G) over time.
The BESA UK Test Regime is to represent the interests of users – this explicitly includes end consumers as they are the ones that benefit the most from having an efficient DH system. Performance of existing systems can be as dramatic as having a 25% efficiency, so the customer ends up paying way too much for their heating and Domestic hot water. Having an efficient HIU in the chain is key to achieve this.
CP1 – A voluntary Code of Practice for the design of heat networks, created by CIBSE – Phil Jones already exists and is also voluntary. This document is to be updated and will probably have BESA test integration in the new version.
"A lower overall VWART represents a lower average annual return temperature from the HIU to the primary network and therefore a better performing HIU."
VWART stands for Volume Weighted Average Return Temperature (VWART). The VWART is an estimation of the annual volume weighted average return temperatures for domestic hot water, space heating and keep warm function. The results reflect the expected impact of the HIU in different operating modes, mimicking the demands they might expect to experience across a year in a typical new build development.
A lower overall VWART represents a lower average annual return temperature from the HIU to the primary network and therefore a better performing HIU. For each test, VWART provides a figure that represents the average impact that a specific HIU will have on network return temperature, under normal operation.
In total, FairHeat calculates the following six derived measures based on test outputs:
These derived results are calculated by FairHeat using the methodology set out in this document. It should be noted that the reported VWART figures are only applicable to the test operating parameters. Actual VWART performance will depend on the operating parameters for each network.
Flamco has been involved in the development, production and sale of high-quality components for use in HVAC systems since 1956. It is part of the stocklisted Aalberts NV, instituted in 1975. Along with Comap, which helps manage water and energy through its thermal and sanitary products that increase comfort in buildings, the Aalberts hydronic flow control business unit was constituted. Stronger together, Flamco and Comap will continue to build mission critical technologies to manage heating and cooling humanly with better financial and environmental efficacy. From source to emitter we partner with our customers to engineer seamless energy efficient hydronic systems for their building requirements.
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