Introduction

Condensation in chiller rooms can be a persistent problem, leading to potential damage and inefficiencies. Especially in areas of high humidity as in Lagos in Nigeria. One effective solution to mitigate this issue is the use of strip curtains. Here I explore how strip curtains can help reduce moisture and condensation, as well as other common causes of condensation in chiller rooms.

How Strip Curtains Help

Strip curtains are flexible, overlapping strips that hang across doorways or openings in chiller rooms. Here are several ways they contribute to reducing moisture and condensation:

1. Temperature Control -> Strip curtains minimize the exchange of warm air from outside and cold air from inside the chiller. This barrier helps maintain a stable internal temperature, which is crucial for preventing warm, moist air from condensing on colder surfaces like the ceiling.
2. Moisture Reduction -> By limiting the influx of warm, humid air, strip curtains help lower the overall humidity levels inside the chiller. Reduced humidity directly translates to less condensation forming on surfaces.
3. Energy Efficiency -> Maintaining a stable temperature means the cooling system doesn’t need to work as hard, enhancing efficiency. Efficient cooling operations contribute to a more consistent internal environment, reducing the risk of condensation.
4. Airflow Control -> Strip curtains manage airflow within the chiller, preventing the mixing of warm and cold air. Controlled airflow helps avoid warm air pockets that could lead to condensation on the ceiling.

Other Causes of Condensation in Chiller Rooms

While strip curtains are effective, it’s important to address other factors that might contribute to condensation:

1. Inadequate Insulation: Poor insulation in walls, ceilings, or floors can lead to temperature imbalances, causing condensation. Ensuring proper insulation helps maintain a stable temperature and reduces condensation risks. Chiller rooms must ideally be constructed from material between 75 to 100 mm thick taking into consideration that greater temperature differences between the inside and outside of the freezer or chiller require thicker panels to provide adequate insulation and prevent condensation. The type of insulation material used in the panels (e.g., polyurethane, polyisocyanurate) also affects the overall insulation performance.
2. Frequent Door Openings: High traffic and frequent door openings allow warm, humid air to enter the chiller, leading to condensation. Limiting door openings and using strip curtains can mitigate this issue.
3. Faulty Seals: Worn or damaged door seals can let in warm air, increasing humidity and condensation. Regular maintenance and replacement of seals are crucial.
4. Improper Ventilation: Inadequate ventilation can trap humid air inside the chiller. Ensuring proper ventilation helps circulate air and maintain appropriate humidity levels. Achieving proper ventilation in chiller and freezer rooms is crucial for maintaining consistent temperatures, reducing condensation, and ensuring the efficient operation of the refrigeration system.
5. High Humidity Environment: Chillers located in areas with naturally high humidity may struggle more with condensation. Dehumidifiers or additional moisture control systems can help manage this.

Adequate ventilation is sometimes a tricky business. One effective method is the installation of exhaust fans, which help to remove warm air and moisture from the room. Exhaust fans should be placed at the highest points where warm air tends to accumulate, such as near the ceiling, to effectively vent out the heat and humidity. Additionally, using air curtains above doorways can create a barrier of air that minimizes the amount of warm air entering the room when doors are opened.

Ensuring adequate air circulation within the chiller or freezer room is also essential. This can be achieved by installing circulation fans that promote consistent airflow throughout the space, preventing the formation of stagnant air pockets and ensuring even temperature distribution. Vents and louvres can also facilitate cross-ventilation, allowing fresh air to enter while expelling warm, moist air. Regular maintenance of these ventilation components is necessary to keep them functioning optimally; this includes cleaning and inspecting fans, vents, and air curtains to prevent blockages and inefficiencies.

The Official View of Strip Curtains

A friend of mine, Daniel Grové did me a favour by outlining the official position on stripcurtains. With his permission, I give his comments verbatim.

Danie writes “I‘m not a fan of Strip Curtains…from a hygiene perspective, the bacterial buildup on them is a nightmare! In my opinion, a good quality air curtain is a better solution to do the same job.

The references you used all assume the RH outside the chiller is below 50%. The conditions in Lagos are often close to 80% RH inside the building. The first step to control the condensation in the chiller rooms must be to control the RH and temperature surrounding the chiller rooms. One needs to insulate the ‘box’ (building) – similar to the insulation and joints of the chiller rooms, and close all doors, windows and openings, using solid materials, strip curtains or air curtains. (For interest sake, the typical blocks used in construction in Lagos are of such poor quality that they let humidity seep through)

Once the ‘box’ has been insulated as best as possible, one needs to consider the Air-conditioning system used. Here the refrigeration references you visited probably assumed the ambient temperature is below 23 degrees at any given time. In Lagos, this is not a given! The air surrounding the chiller room must be Air-conditioned to keep the temperature below 23 degrees. Now for the important part; the fresh air that get pumped into the system cannot have high humidity, do not use standard AHU’s, but use TFA’s (treated fresh air) to remove the humidity. Now that the air surrounding the chiller rooms is below 23 degrees and also below 50% RH, everything you mentioned in your article kicks in and I agree with it all.

The set-up cost is obviously quite a bit higher on this route, but the longevity of your chiller rooms, and the reduced cost of both maintaining the plant and the energy cost of running it, make this route the better one to take.”

Danie is well experienced in challenging environments like Nigeria and many other African countries. The link attached to his name is to his LinkedIn profile and if the services of a well-experienced architect or project manager are required for challenging retail and other projects, you will be well advised to seek his input.

Conclusion

Of course, Danie is right in his assessment. I’m not overly concerned about the hygiene implications as long as its managed through processes and procedures. particularly as far as the use of strip curtains in freezers is concerned. They should also be installed in such a way that in chiller rooms they can be removed every week and washed. The downside to its use is far outweighed by the upside, especially where air curtains are not an option from either a maintenance or budgetary perspective. If treated fresh air is used it must most definitely be cooled before it’s injected into a temperature-controlled space.

Generally speaking, managing condensation in chiller rooms is essential for maintaining efficiency and preventing damage. Strip curtains offer an extremely effective solution by controlling temperature, reducing humidity, and managing airflow. Remember that addressing other potential causes like insulation, door seals, and ventilation is equally important. Implementing a comprehensive approach ensures a moisture-free and efficient chiller environment.

References:

1. ASHRAE Handbook – Refrigeration: Provides comprehensive guidelines on refrigeration systems, including ventilation requirements and best practices. Available at ASHRAE.
2. Cooler Manufacturer Guidelines: “Best Practices for Reducing Condensation in Commercial Refrigeration.”
3. Energy Star: “Commercial Refrigeration: Temperature and Humidity Management.” Energy Star
4. Energy Star: Offers insights into energy-efficient practices for commercial refrigeration, including ventilation strategies. Available at Energy Star.
5. HVAC/R Engineering: “Controlling Humidity and Condensation in Refrigeration Units.”
6. Kingspan Insulated Panels: Provides specifications and guidelines for insulated panel products, which are critical for maintaining temperature control in refrigerated spaces. Available at Kingspan.