BSEE ENERGY EFFICIENCY
Improved energy efficiency and sustainability remain priorities for building designers and their clients. Anthony Barnett, Technical Marketing Manager at Armacell, looks at how simple, cost effective steps within the distribution system can help acheive these objectives.
increasing the share of renewable energies by 20% by 2020. This important legislation affects all HVAC equipment and requires that they meet minimum energy efficiency requirements. As part of this, space and water heaters, including HVAC units, are required to display the same type of energy efficiency labels as fridges and freezers.
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A consequence of the introduction of ErP is that manufacturers of HVAC equipment have focused on developing more energy efficient boilers, air conditioning and refrigeration units. As a result, many of these now achieve an A or A+ rating for energy efficiency. However, the fact that you specify an ErP asset that achieves the highest rating does not necessarily guarantee energy efficiency because, once it’s connected to a distribution system, that, too, has to achieve the highest performance standard.
Whole system insulation
Pipework in HVAC systems is usually insulated as a matter of course, in line with building regulations, although pipe supports are often overlooked. That means these critical points, which in a large system can number several hundred, remain uninsulated. This results in significant heat losses in a system, with the consequences being reduced energy efficiency and deterioration of assets due to condensation. Failing to insulate pipe brackets adequately can therefore negate many of the energy efficiency benefits of choosing an ErP asset with the highest rating.
uDepending on the pipe diameter, the heat loss from an uninsulated pipe bracket (below left) can be equivalent to that from up to 1m of uninsulated pipe. (Illustration: Armacell)
The effects of pipe brackets not being insulated can be seen in Figure 1 using a thermal imaging camera. The extent of this loss of energy can be significant, with thermal heat flow calculations for a 60°C hot water pipe in continual use showing a heat loss of 0.06 w/k per bracket (on a 26.9mm diameter copper pipe with a 27mm insulation thickness). This can increase total energy costs of running a facility, especially where a large number of supports are used. It’s worth bearing in mind that each uninsulated pipe bracket loses around £2 each year in
n September 2015, the new Energy related Products (ErP) directive came into force with the aim of helping EU countries achieve a target of reducing energy use by 20% and
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OPTIMISING THERMAL PERFORMANCE A whole system approach to energy efficiency
wasted energy and, considering the number of brackets in a system, this can soon add up to a significant amount. Conversely, the payback from fitting these kinds of simple solutions can be rapid.
When it comes to cold water systems, condensation can be an issue when pipe brackets remain uninsulated. Aside from the wasted energy costs, this moisture results in rapid deterioration of metallic components, reducing its life as well as causing contamination issues, which is a concern in certain production environments such as food and pharmaceutical. The best method of preventing condensation is to avoid direct contact between the pipe and its bracket by using insulated pipe supports.
A‐rating for closed‐cell insulation
When choosing an insulated pipe bracket for both hot and cold applications, closed-cell elastomeric nitrile rubber insulation, which has a high resistance to water vapour transmission and low thermal conductivity, is best able to protect against energy losses and condensation. In addition, using the same insulation materials for the pipework and support brackets ensures compatibility and allows them to be installed and glued to each other along the entire system.
An increasing number of engineers are choosing to use pre-fabricated elastomeric insulation supports such as Armafix X, with self-seal seams for quick fixing the insulation onto the pipe. The low thermal conductivity value and high water vapour resistance provides protection against energy losses and condensation, whilst the load-bearing segments prevent the insulation material being compressed. It’s also worth bearing in mind that the BRE (Building Research Establishment) has just added a category for pipe insulation materials to their Green Guide to Specification, with nitrile rubber insulation products such as Armaflex flexible elastomeric foams (FEFs), receiving an ‘A’ rating. This ‘A’ rating in the Green Guide enables building services engineers to specify nitrile rubber insulation materials as a sustainable option. Being an independently verified FEF insulation with the highest water vapour resistance and lowest thermal
conductivity ratings, ensures that it offers the best long-term solution for ACR applications and a highly efficient option for heating and ventilation services.
Conclusion
The ErP has resulted in a significant change in the performance of heating and ACR equipment specified in the UK. Manufacturers are now focusing their efforts on the top energy rated models, whilst installers, armed with the knowledge that simple steps such as insulating pipe brackets in the system can maintain efficiency, are pushing forward the boundaries of overall system efficiency.
We can see, therefore, that achieving an efficient system is much more than simply specifying an A+ rated device. Building engineers need to look at the whole system because the boiler, air conditioning unit or other asset does not just sit there in isolation. That’s because connecting an A+ rated asset to a distribution system will immediately impact on its stated energy efficiency. True efficiency comes from the whole system and not just the boiler. Thermally isolating the pipe from its fixing and specifying a closed-cell, A-rated insulation material are simple, low cost but very effective methods of ensuring optimum thermal performance.
www.armacell.co.uk
uInstalling Armafix pipe supports.
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Pipework in
HVAC systems is usually insulated as a matter of course, in line with building regulations, although pipe supports are often overlooked. That means these critical points, which in a large system can number several hundred, remain uninsulated. This results in significant heat losses in a system.
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Figure 1 22 BUILDING SERVICES & ENVIRONMENTAL ENGINEER JUNE 2017
uArmafix X pipe supports with integrated load bearing segments.
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