Bosman Van Zaal - South Africa
Bosman Van Zaal - South Africa

The Crucial Role of Dehumidification in Greenhouse Efficiency

Greenhouses have altered modern agriculture by creating controlled settings for plant growth, allowing for year-round cultivation and increased yields. However, maintaining perfect conditions within a greenhouse can be difficult, especially when it comes to humidity control. Dehumidification is an important feature of greenhouse climate control, particularly in cannabis growing, where accurate humidity management can have a substantial impact on plant health and yield. This article discusses the relevance and benefits of dehumidification in greenhouses, with a focus on the many types of dehumidifiers available, their efficacy, and factors to consider when selecting the best dehumidification solution.

What is Dehumidification and Why is it Important?

Dehumidification is the removal of excess moisture from the air. Maintaining an ideal relative humidity (RH) level in greenhouses creates a favourable environment for plant growth. Excess humidity can cause a variety of issues, including mould and mildew growth, pest infestations, and illnesses, all of which have a negative influence on crop health and output.

Humidity control is especially crucial in cannabis greenhouses. Cannabis plants flourish in specified humidity levels, usually between 40% and 60% RH, depending on their growth stage. High humidity levels can cause mould and bud rot, reducing harvest quality and quantity. Low humidity, on the other hand, can stress plants, preventing them from growing and developing properly. Effective dehumidification is critical to the viability of cannabis cultivation.

Types of Dehumidifiers: Refrigerant vs. Desiccant

Dehumidifiers are crucial tools for controlling humidity in greenhouses. In agricultural contexts, two types of dehumidifiers are commonly used: refrigerant and desiccant.

Refrigerant Dehumidifiers
Refrigerant dehumidifiers operate by pulling moist air over a cold coil, causing the moisture to condense into water droplets that are collected and removed. The dry air is reheated and discharged back into the greenhouse. These dehumidifiers are extremely effective in warm, humid environments and are often used in greenhouses where excessive humidity levels are a typical concern.

Image: Andrew Sykes Group PLC

Desiccant Dehumidifiers
Desiccant dehumidifiers work in a different way to remove moisture from the air. They use a desiccant substance, such as silica gel, to absorb moisture from the air. The saturated desiccant is then regenerated by heating, releasing the moisture, and the cycle repeats. Desiccant dehumidifiers work in a wider temperature range and are especially beneficial in cooler locations where refrigerant dehumidifiers may not be as effective.

Image: Andrew Sykes Group PLC

What Are The Differences Between Refrigerant and Desiccant Dehumidifiers?

Efficiency
Refrigerant dehumidifiers are more energy-efficient in warm, humid climates, but desiccant dehumidifiers are efficient across a wider temperature range.

Operating Temperature
Refrigerant dehumidifiers perform best at higher temperatures, but desiccant dehumidifiers are excellent at low temperatures.

Moisture Removal
In warm temperatures, refrigerant dehumidifiers often remove more moisture per unit of energy consumed, but desiccant dehumidifiers perform better in low-humidity environments.

Maintenance
Refrigerant dehumidifiers require coil and drainage system cleaning on a regular basis, whereas desiccant dehumidifiers require periodic desiccant material replacement or regeneration.

In a recent case study, a specific greenhouse installed a high-performance dehumidifier and saw a significant decrease in relative humidity. The RH% in the greenhouse decreased from 88% to 55%, proving the usefulness of sophisticated dehumidifier technology. This significant fall in humidity levels contributed to a better environment for the plants, lowering the danger of mould and disease while enhancing overall crop quality.

The Efficacy of Extracting Humidity Out of the Air

Dehumidification in greenhouses is only as successful as its ability to absorb humidity efficiently and maintain consistent humidity levels. Advanced dehumidifiers are designed to handle massive volumes of air while removing significant amounts of moisture, keeping the greenhouse environment within the ideal RH range.

Extracting humidity from the air entails many fundamental processes:

  1. Proper air movement is essential for effective dehumidification, ensuring moisture enters the dehumidifier. Fans and ventilation systems serve to disperse air uniformly throughout the greenhouse.
  2. The dehumidifier removes moisture from the air and gathers it in a reservoir or drainage system. This collected water can be reused for irrigation, hence increasing resource efficiency.
  3. Modern dehumidifiers use sensors and automation to continuously change performance based on humidity levels.

Application of Dehumidification

To achieve appropriate humidity control in greenhouses, dehumidification is used in a variety of ways.

  1. Standalone Units
    Individual dehumidifiers can be carefully placed throughout the greenhouse to focus on regions with excessive humidity.
  2. Integrated System
    Dehumidification can be included into the greenhouse's entire temperature management system, working in tandem with heating, cooling, and ventilation systems to maintain a balanced atmosphere.
  3. Automated Control
    Advanced dehumidifiers include automation and monitoring features, allowing for precise control and adjustment based on current humidity levels. This guarantees that the greenhouse's humidity levels remain consistent without manual intervention.

Energy Efficiency in Dehumidification

Energy efficiency is an important factor in the selection and operation of dehumidifiers. Traditional dehumidifiers can consume large quantities of electricity, resulting in significant operating expenses. However, the unique dehumidifiers utilized by Bosman Van Zaal provide significant energy savings while maintaining great performance.

For example, Bosman Van Zaal's dehumidifiers use only 10 kW of power, compared to the conventional 80 kW, resulting in significant energy savings. Despite using less energy, these dehumidifiers significantly reduce humidity levels, resulting in a healthy and productive greenhouse environment.

What to Consider When Looking at Efficacy

When analysing the efficacy of dehumidifiers for greenhouse applications, numerous criteria should be taken into account:

  1. Capacity
    The dehumidifier's capacity to remove moisture per hour should be proportional to the greenhouse's size and humidity conditions. Larger greenhouses or those with high humidity levels may necessitate numerous units or higher-capacity versions.
  2. Energy Consumption
    The energy efficiency of the dehumidifier is critical for economical operation. Look for units with energy-saving features and minimal power consumption.
  3. Automation & Control
    Advanced dehumidifiers with automated controls and monitoring systems provide higher accuracy and convenience of operation. These characteristics ensure that the dehumidifier runs efficiently and responds to changing humidity levels.
  4. Maintenance Requirements
    Dehumidifiers require regular maintenance to work properly over time. Consider devices with simple maintenance processes and dependable components to save downtime and repair expenses.
  5. Environmental Conditions
    The greenhouse's specific climatic conditions determine whether to utilise refrigerant or desiccant dehumidifiers. Assess the temperature and humidity levels to find the best type.

One of the primary advantages of cooperating with Bosman Van Zaal is our holistic approach to assess each client's unique engineering requirements and give specialised solutions to specific issues. We maximise the performance and efficiency of every dehumidification system by leveraging our agricultural engineering experience.

Our solutions are both effective and sustainable, taking into account long-term operational expenses and environmental impact. Bosman Van Zaal assists growers in achieving optimal temperature conditions, which improve crop quality and output, by combining innovative dehumidification technology with comprehensive expertise of greenhouse systems.

We recognise that dehumidification is an important aspect of greenhouse climate control, especially in cannabis cultivation, where accurate humidity management is key for plant health and productivity. Understanding the many types of dehumidifiers, their efficacy, and energy efficiency factors will assist greenhouse operators in selecting the optimal solution for their specific needs.

Bosman Van Zaal's innovative dehumidification technologies provide numerous advantages, including lower energy usage and improved humidity control. If you want to learn more about dehumidification and how it can help with your greenhouse operations, please contact us at info@bosmanvanzaal.co.za.

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Bosman Van Zaal has 90 years of experience in the development and construction of greenhouses and over 40 years' experience with technical systems for international horticulture.

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