Dave Bull, Business Development & Applications Manager, Condair plc

Author: Dave Bull, Business Development & Applications Manager, Condair plc


The specification of humidification

Ensuring you specify the correct humidification system largely depends on being able to extract the right information from the end-user on how the system will be employed. However, it’s difficult to build-up enough experience to know the right questions to ask when projects involving humidifiers don’t occur that frequently in a HVAC consultant’s career.

Following this basic guide should stand you in good stead and help you avoid the most common specification errors we come across as the world's leading humidifier supplier and installer.

1 - What level of humidity is required and what level of fluctuation is acceptable?

Different applications will require different levels of humidity control. The most common application for a HVAC consultant will be the office environment’s requirement of between 40-60%rH (relative humidity). At this level people are comfortable and static build-up is reduced.

Many manufacturing industries will require a more specific level of humidity control. For instance printers need to control humidity to a tighter 50-60%rH. Textile manufacturers will need a higher 65-75%rH. An ideal museum environment is between 45-55%rH but with daily fluctuations being limited to ±3%rH to safeguard valuable exhibits. Some pharmaceutical applications need an even tighter ±2%rH to prevent product wastage.

If an application requires tight control of humidity then the humidifier selection will be restricted to systems that give very fast responses to a drop or increase in humidity, like resistive steam or spray units. Water treatment may also be required to improve the consistency of performance.

Evaporative humidifier and cooler

Some in-duct evaporative humidifiers, such as the Condair ME, can provide up to 12°C of adiabatic cooling...


2 – How long will the humidifier be running for and when can it be shut down?

If a humidification system is going to be used 24/7 then the number and type of humidifiers will need to reflect this. A critical system that needs to be constantly delivering a certain level of humidity must include run and standby humidifiers as every humidifier in the world needs to be shut down occasionally for maintenance.

3 – How important are running costs and the environmental impact of the system

Running costs vary widely with different types of humidifiers. Some steam systems can use 150 times more energy than an efficient evaporative humidifier and require six times more to be spent on them in servicing and spare parts. The initial purchase cost is a lot less for the steam system but an error in the initial product selection can cost the client (and the environment) dearly over the life of the unit.

Consideration should also be given to the advantages of using some evaporative humidifiers to reduce the running costs associated with the building’s cooling system. Some in-duct evaporative humidifiers, such as the Condair ME, can provide up to 12°C of adiabatic cooling to an AHU system. This can reduce the running costs associated with DX chillers and reduce the building’s overall carbon footprint.

4 – What types and how much energy is available?

This is a critical question as it’s not unheard of for contractors to arrive on site to install equipment only to find out that the amount of electricity required to run a humidification system is not available.

Humidifier water filter to improve performance

Reverse osmosis water filter help improve the quality of the water and reduce servicing...


For really large duties, the energy requirements of using an electrical system can become prohibitive and either evaporative, spray or gas humidifiers may be a more viable option for the end-user.

5 – What quality water is being used and what level of maintenance is acceptable?

Water quality and maintenance are intrinsically linked when dealing with humidifiers as a poor water quality inevitably leads to a higher servicing requirement. The minerals left behind in the humidifier when the water is either boiled or evaporated into an atmosphere need to be dealt with.

If the water has a high mineral content but a high level of maintenance is unacceptable, water treatment should also be specified. This can take the form of reverse osmosis filters and water softeners to help improve the quality of the water and reduce the level and frequency of servicing.

6 – What evaporation distance is required?

For humidifiers providing moisture to ducts or AHU systems, the humidifier must be able to evaporate the moisture into the air stream before it meets physical obstructions, like duct corners, otherwise this will cause condensation. If the available evaporation distance is short, specialist steam lances can be used, which give evaporation in under 60cms, or evaporative humidifiers specified, which provide instant evaporation.

ROI calculation for humidifier selection

...it is always worthwhile drawing up a matrix of capital cost vs running cost, as budgets are often set without this in mind...


7 – Where are the humidifiers to be situated?

If access to the location is restrictive certain humidifiers may be easier to install than others. Also, if a unit is located in an awkward position then servicing may be difficult or sometimes impossible. Doors to the humidifier need to unhindered to gain access to the internal components. Mounting height should also be considered as if the humidifier is too high, routine maintenance may be made more difficult and could require two engineers rather than one to attend site.

Budgets & Advice

Although this is a concise list of the some of the most pertinent questions for the selection of humidification equipment, asking them will help you to get a clearer picture of the end-user’s ideal requirements. However, the “ideal” obviously has to be balanced up against the available budget. While trying to reach this balance it is always worthwhile drawing up a matrix of capital cost vs running cost, as budgets are often set without this in mind. A higher investment in the initial equipment than the proposed budget can often be in the client’s best interests.

Condair offers specifiers of humidification equipment a free in-house, lunchtime CPD seminar to go over these and many more issues. For more information click here or to book complete and submit the form on the right of this page.

Want expert advice from Dave about specifying humidifiers?

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Arcade

Joss Williams

Senior Project Manager

“The humidifier meets Polestar’s requirements and the customer is happy. Previous experience of Condair has been good. The guys that attended site changed the design to suit the site location with no issues in relation to price. The installation was of a high standard and looks good.”

Christ’s Hospital School

Peter Dutton

School Organist

“Condair clearly had experience in working with such ancient and delicate organs and was quickly able to propose the most suitable model, as well as its positioning for installation.

It has made a real difference in keeping the humidity in the organ chamber stable and we are now able to play the organ whatever the weather is like outside; even during the cold, dry conditions of last winter.”

Opera North

Richard Ashton

General Manager

“After meeting with Condair, we felt confident that the company understood our specialised requirement, not just the level of humidity, but also the need for reliability, flexibility and cost effectiveness.

Since installing humidification, which we switch on as and when required, our musicians have felt much more at ease regarding the safety and performance of their instruments.”

Irish Water

Michael Cooney

Executive Engineer

“Absolutely fantastic presentation today one of the best explaned presentations I attended in years, really impressed thank you.”

Sporting Edge UK Ltd

Dave Vincent

Managing Director

“Sporting Edge produce the most advanced environmental chambers in the world and it’s vital all parts of our system offer consistent reliability and performance. This is why we have standardised our humidity control using the Condair RS steam humidifier.

It provides us with a dependable, controllable product that will happily work with standard mains water. We also love the self de-scaling feature.”

ZSL London Zoo

Dave Clarke

Head of Invertebrates

“Having worked with Condair since 2008, we now rely on their steam humidifiers, which we find both efficient and easy to use. They are particularly important for our irreplaceable populations of endangered species, for example our Polynesian tree snails, many of which are now sadly extinct in the wild.”

Aston Martin

Alan Darrock

“We need a reliable, effective humidification system to ensure that we can achieve the utmost finish to our cars. Since the new equipment was installed we have seen improvement in the quality of the paint finish, and our workforce now keep the doors closed. We have been more than pleased with the service and skill that Condair offers and will be using them in other production areas.”

ICS Cool Energy

Malcolm Edwards

Group Technical Manager

“The JetSpray has been in operation now for a number of months keeping the humidity well over the required 90%RH and maintaining a very low 0.67% weight loss. The energy and water savings are a bonus and economies will also be achieved through its easy maintenance programme. All in all, our client could not be happier, and neither could we.”

John Watson & Co

Chris Fyfe

Quality Assurance Manager

“When paper loses moisture, ink will not adhere properly, which could cause a problem for our printing company whose reputation for quality is high. Not only has the JetSpray been proven in our industry, it is also uncomplicated, energy efficient and extremely hygienic in operation.

Due to the conditions in our print room, the humidifier has been running 99% of the day since installation, keeping RH at a perfect 50%.”

EDPAC

Noel Lynch

Managing Director

“The complementary technologies of air-to-air heat exchange and humidifier-based evaporative cooling is a considerable improvement to existing indirect data centre cooling systems.”

Fujifilm

Steve Freeman

Jet Press Solutions Manager

“Humidity control is important for paper handling consistency when running lighter weight stock on the Jet Press 720S in both the feeder and jetting area. We aim to maintain an RH of between 40% and 60%. Below this could potentially cause an increase in paper handling issues on light weight paper.

Once the humidifier was up and running correctly, it has performed well. It now easily and quickly gets the room up to the required RH and maintains this after start-up.”

T Clarke

Doug Lumb

Project Engineer

“The Condair DC 50W dehumidifier was actually chosen by our designers, as it fitted the bill perfectly for the environment. The unit size was based on the quantities of kit hung in the room to dry when the firefighters return to the Centre at the end of their training exercises.

It’s a reliable product and currently operating at the station just as expected, plus installation was really simple and didn’t take long at all, so all very good.

I would definitely specify Condair dehumidifiers for future projects.”

The Savanna

Lisa Gardshol

Founder and CEO

“We have been very happy with the performance of the Condair dehumidifiers JTR installed to comply with our drying approach. It has not only allowed us to increase production efficiency but also produce our award-winning biltong.

We have full control over the entire process and can make decisions based on the data that we recieve. This is something which we couldn’t do as well before.”

John Todd Refrigeration (JTR)

Matt Gough

Refrigeration Engineer

“The rooms need very tight environmental control but the previous strategy introduced outside air to help lower temperatures when needed. JTR redesigned the drying rooms and installed Condair DC-N dehumidifiers.

The dehumidifiers, located in the rooms, both dry and heat the air to the required condition, resulting in a fully sealed area and a consistently controlled drying process.”

Altipeak™ International Holdings Ltd

Noel O’Brien

Founder and CEO

“The Altipeak™ Mobile Altitude Pod was initially designed to assist athletes acclimatise for the Tokyo Olympics. Our chambers can monitor and control oxygen and CO2 levels, as well as temperature and humidity.

So it was very important to us that the humidity control system in our mobile training chamber was responsive and accurate, as well as being easy to use. We selected the Condair EL steam humidifier, as it offered us the humidity outputs and control level we needed, and has a built-in touch screen controller, which makes operation really simple.”

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