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Biddle Air Systems Convector |
The UK fan coil market last year was valued at £29.7 million representing a volume of 64,700 units. (Data from BSRIA market research). This represented a fall of 16 percent from 2003 and is reflecting a continued downward trend in the last few years. This has been a reflection of a number of factors:
The slack in the construction sector and the stagnation of the office sector.
Continued pressure from the competition of alternative systems, such as chilled ceilings/beams, VRF and other mini split systems, which continue to show significant growth rates.
Increasing demand on noise emission standards.
Oversupply in the market place.
The UK fan coil market has always been seen as being over-engineered and comparatively expensive compared with other places in the world. Thus with aggressive sales and marketing from suppliers of alternative systems in a slack market with increasing pressure on demonstrating energy efficiency, traditional chiller-fan coil systems have suffered at the small-medium end of the market. However we have seen fan coils falling in most markets across Europe during 2005.
The shrinking market, combined with increasing competition has made it difficult for suppliers to pass on increases in material costs. Consequently profit margins are being squeezed and although there are still some 25-30 companies operating on the UK market, 2004 brought some major changes in the league tables.
Although the market is fragmented, the top 8-10 companies account for the bulk of the market. Diffusion is the market leader, previously followed by Quartz, Ability Projects, Eaton Williams and chiller manufacturers, such as Dunham Bush, Carrier and Lennox. In 2003, these players had a combined market share of around 60 percent. However, in 2004, Quartz’s fan coil arm was acquired by Marstair and thus putting them in second position in the market in the UK, although otherwise the ranking order has not been changed.
80 percent of units sold in the UK are of the concealed type. It is particularly the cased mini split types which have experienced strong competition from VRF units. Clearly, although there is a certain market for replacement, the majority of sales of fan coils are linked to the sales of chillers, or refurbishment of existing systems. The overall chiller market is expected to see a relatively conservative growth in the next five years (1-2 percent by value). It will be some time before the preparation of the Olympics in 2012 will take effect and consequently, the market for fan coils will remain at a similar level and remain at best fairly flat, due to expected continued competition from other AC systems.
Independent testing and certification
One of the main challenges that the manufacturers are facing in this competitive market is guaranteeing performance of their products. From its extensive experience in fan coil testing, BSRIA have found that some of those products had the performance which is 25-30 percent down on catalogue data.
Reliable performance data demonstrates that equipment is fit for use and are key to minimising risks on projects.
Independently tested and certified products provide the guarantee that the performance has been accurately published and verified, and help manufacturers compete on product quality with confidence. Also, the testing provides reassurance to project teams that the systems will satisfy particular requirements.
Modifications to these products, often to meet client specific demands, for example low profile casings or air plenum changes, can affect the way the fan coil performs leading to a shortfall in performance. The costs if this is discovered on site after installation far outweighs that spent on pre installation tests.
Development tests can be shortened to determine if a modification is going to work. This enables possible solutions to be narrowed down before conducting a full test, and a number of these short form tests can be conducted during a working day.
While modern computer selections can, in most instances, give a prediction of performance, based on known standard data, the number of tests originally used to determine the performance calculation matrix will not have covered every option. So while the computer provides the selection, if you are going to install a considerable number of fan coils the validation of the specific performance for the job becomes an issue.
It is possible to conduct some tests on site or at manufacturer’s facilities dependent on the particular installations and access issues.
Real time performance testing
Thermal performance of fan coil units can be determined using two methods: waterside and airside calculations. Waterside calculations do not account for air leakage from the fan coil unit, casing thermal losses or gains, or exposed sections of the cooling/heating coils. Airside calculations, whilst accounting for this, are more complex and involve measuring air temperatures, moisture content and mass of air supplied at the unit outlet. Total thermal duty of the coil is most accurately obtained by waterside measurements. Latent duty can be obtained by collection of condensate or airside enthalpy.
The use of two methods of calculating the unit’s thermal performance ensures an enhanced level of accuracy, and acts as a double check of the results obtained. This is a requirement of the ISO specifications used. In addition, thermal imaging can be used during product development to check surface temperature.
Processing all the data electronically enables the unit’s performance to be observed in real time. This means that any fine adjustments can be made during testing to meet the client’s specific requirements.
Case study
BSRIA works in close co-operation with manufacturers to test and improve designs and demonstrate the suitability and reliability of products for the market or for particular projects. We test fan coil to BS 4856 and Draft ISO, ASHRAE and Eurovent Standards, or against set design conditions.
Biddle Air Systems Ltd contracted BSRIA to carry out independent development tests on their Low Surface Temperature (LST) fan convectors. The objective was to measure thermal performance and test the product against the NHS Estates Health Guidance Note: “Safe hot water and surface temperatures” (1998).
The Guidance requires that: “The maximum surface temperature of space heating devices should not exceed 43°C when the system is running at the maximum design output”. It states that heat emitters should be designed so that: “There are no surface hot spots”.
The test samples consisted of finned tube low surface temperature fan convectors from the Biddle Air Systems range of products. This was a novel design of a unit with two valves: one controlling room temperature and the other controlling the leaving air temperature. This concept enables the output from the unit to be controlled so that the leaving temperature is not over 43°C at water conditions of 80°C and above.
For this purpose BSRIA used two different facilities: the radiator test room and fan coil chamber. The chambers are constructed to meet the requirements contained in BS EN 442-2: 1997 and the BS 4856 draft ISO standard.
The fan coil unit was located in the test chamber, where the supply air to the unit was pre-conditioned to provide the correct on-coil temperatures. The tests were set up with water on-coil and air on-coil conditions.
In addition hydraulic resistance tests were carried out on water heating coils, with complete valve assemblies and thermostatic heads. The hydraulic resistance data is important for specifiers in order to determine the pump size or HVAC system requirements for a particular application.
The test results confirmed that the LST type fan convectors could maintain an ‘air off’ temperature of 43°C at an inlet water condition of 80°C when adjusted to suit the environmental conditions. This proved that the novel concept, which is “patent applied for”, will work.
In summary
By independently evaluating product performance and certifying compliance with standards manufacturers can:
Confirm that the product has achieved a recognised level of quality.
Increase credibility in product performance and consumer confidence.
Ensure that the product will perform as stated.
Increase credibility in product performance.
Enhance product superiority and competitive advantage.
