Maximising Energy Efficiency: A Guide to Louvre Systems
Posted on - 10th July 2024
In today’s world, energy efficiency is no longer just a ‘nice-to-have’, rather it is of critical importance in the fight against climate change, in nations’ efforts to gain energy independence and in reducing costs.
Louvre systems often go unconsidered when designing ventilation systems beyond their size and colour, however, an incorrect choice can have significant impacts through increased running costs and more frequent maintenance, not to mention potentially increased noise levels creating a nuisance.
Understanding The Basics of Louvre Systems
Before we discuss energy efficiency, let’s take a moment to understand the basics of louvre systems. Louvres are part of an HVAC system and are normally located on the exterior wall of a domestic or commercial building. Specialist louvres like Series PHL Penthouse Louvres are also designed to be installed on rooves.
The main purpose of most louvre types is to serve as the external terminal of a ventilation system, i.e. they are the devices through which outside air is pulled into the system, or through which inside air is ejected to the outside. Louvres come in many different types but almost always consist of a frame and a blade design. Depending on the exact design of the blades, they can provide additional benefits such as solar shading, low resistance to airflow and noise reduction.
How Do Louvres Maximise Energy Efficiency?
It’s important to say that not all louvres are intended to maximise energy efficiency. Traditional louvres like our Series WL Standard Louvre range are designed with a ‘classic’ louvre appearance as the primary concern. Horizontal blades, each with a relatively large front face provide exactly this. Whilst this gives the classic louvre appearance we’re all familiar with, this design does detriment airflow through the generation of increased pressure drops, meaning fans have to work harder to pull air past the louvre, in turn meaning higher energy consumption. The reality is though that for most projects the pressure drops generated are within the working range of any fans in the system, and so running and maintenance costs remain as expected. We manufacture more of this type of louvre than any other.
Similarly, some specialist louvres have design priorities which conflict with them being energy efficient. Series AL Acoustic Louvres are a perfect example of this. These are designed with the primary focus being effective noise attenuation which necessitates a large, angled blade with relatively small airflow channels; this unavoidably detriments airflow.
Some louvres however are designed with energy efficiency being a top concern. These louvres largely achieve this through novel blade designs which disregard the requirement for a ‘classic louvre’ appearance in favour of aerodynamics, the key metric being pressure drop expressed in Pascals (Pa) which details how much resistance a louvre presents to air being pulled through it at specific velocities. On the face of it, this should be easy; a louvre with thin vertical blades running parallel to airflow would generate an extremely low pressure drop, however, the key difficulty is that this needs to be balanced with high levels of rain rejection, a louvre as described above would present little to no barrier to significant levels of rain ingress, almost certainly resulting in damage to a building’s fabric or internal equipment.
This is the question on which many louvre manufacturers are focused; how do you minimise the resistance caused by putting something (a blade) in an airstream, whilst also catching a very significant portion of any rain held within that airstream.
How are louvres compared?
We did an article on this last year which explains exactly how louvres are tested and how results are presented.
Read here: Weather louvre testing: What is EN 13030? - HVC - Knowledge hub - HVC (h-v-c.com)
What can HVC offer by way of very efficient louvres?
This is an area to which HVC has committed significant research and development spend in recent years. Once a need is identified, concepts are evaluated against the desired goals by performing detailed simulations in CFD software to hone a design before investing money in physical product, fabricating a test sample and then performing a real world test.
Currently, we have one high performance weather louvre available in the form of the Series HPL80. This gives better than 99% rain rejection up to a minimum of 2.5 m/s air velocity, but with a pressure drop around half that of a Series WL75 traditional large format louvre. This is the louvre design balance in practice – Much better rain rejection, with much less resistance to airflow.
The HVC range is shortly to grow however with the introduction of at least one specialist vertical blade louvre giving even greater performance, and we are also evaluating our current range of louvres to see whether efficiency gains can be made without adversely impacting key design elements, like the ‘classic’ louvre appearance.
Best Practices For Continuous Energy Efficiency
Correct selection
A basic understanding of how louvre performance is classified can help to ensure you always make the right selection for your application
Adaptation
If the demands on a louvre change, maybe fan speeds are increased to provide increased ventilation or sensitive equipment is placed in the vicinity, it should be verified that the louvre is still the correct model for the job
Maintenance
Regular maintenance of louvre systems is important both to maintain performance and extend their lifespan. This includes clearing the blades of dust or debris and checking the components. If your louvre is damaged or covered in debris, it could negatively affect the energy efficiency of your building and increase your running costs. Luckily, louvres should be relatively easy to replace.
Shop Our Range of Louvre Systems
At HVC Supplies, we are a leading manufacturer of high-performing louvres. Our extensive range includes weather louvres and acoustic louvres to sand trap, glazing louvres and more. With industry-beating lead times, our units are manufactured in-house by our expert team to suit your requirements. If you’re looking to install a new louvre system or replace a damaged one, shop our range today or contact us if you have any questions.
