Greenhouse Cooling Systems & Chillers by Enerdes®

Greenhouses temperatures can be controlled by means of evaporative cooling, also referred to as swamp cooling or adiabatic cooling. Enerdes supplies cooling pads, which will allow for very effective cooling of the air. Greenhouse cooling systems based on cooling pads and fans are the most efficient way to cool a greenhouse. Enerdes can determine for you what size cooling pads you require in order to obtain the perfect growing climate for your crops. 

When evaporative cooling is not sufficient due to geographical location or there is also a dehumidification demand, cold water chillers are the perfect solution to go for. A chiller can also be used to dehumidify the air inside the greenhouse, by means of condensation drying. We at Enerdes compare different scenarios between evaporative cooling and cold water chillers and optimize the benefit of both. Sometimes this will lead to an even more efficient combination, lowering operational costs and giving extra cooling capacity when needed. 

11 Semi-closed greenhouse_Enerdes_Greenhouse climate control

The Enerdes expertise

Greenhouse cooling system by Enerdes®

To cool a greenhouse, the first measures are ventilation and shading. Ventilation can be achieved by creating air circulation with greenhouse fans and opening roof vents and shutter vents. These solutions may not be sufficient or not desired for many reasons such as:

  • It is desired to keep ventilation minimal.
  • The outdoor climate is so hot, ventilation and shading are not sufficient for cooling.
  • Shading is not desired because the sunlight is needed for plant growth.

For big buildings like offices, mechanical refrigeration can be used, also referred to as air conditioning. However, the amount of heat that needs to be removed from greenhouses is so much bigger, air conditioning with mechanical refrigeration is not economically feasible option.

At Enerdes, we know exactly how to develop a greenhouse cooling systems that operates with minimal energy consumption and low costs. First, we determine the cooling capacity required for your crops. How much heat must be removed from your greenhouse in how much time? For this, the following information is obtained:

  • Outdoor climate, average temperature and humidity, maxima, minima etc.
  • Desired indoor climate
  • Greenhouse type
  • Greenhouse area and volume

Commercial greenhouses or industrial greenhouses usually have a big surface area. This means many vents, fans and additional cooling systems are used to provide cooling. It is an incredible amount of work to operate all these units manually. Enerdes can supply a fully integrated greenhouse climate control system as well as separate components. We can also provide the control technology for all separate components and systems that will allow you to monitor and control the climate in your greenhouse.

Having difficulties getting your greenhouse at the right temperature while maintaining proper humidity levels? Enerdes has decades of experience with greenhouse heating, cooling and climate control. We are part of Reinders Corporation, which has been making climate control systems since 1910!

In warm climates or during summer periods, venting your greenhouse may not be enough to cool your greenhouse. At Enerdes we make energy efficient greenhouse cooling systems for commercial and industrial greenhouses. Our greenhouse cooling systems will make sure your crops can grow in their optimal temperature and humidity.

Greenhouse evaporative cooling

When water evaporates in the air, energy is needed. This energy comes from heat which is dissipated from the hot air. The more water can evaporate in the air, the more heat is dissipated and thus the more the greenhouse is cooled. The initial temperature and the initial relative humidity of the air determine how much water can be evaporated and thus what the cooling capacity is and how much the greenhouse temperature can drop.

Evaporative cooling is especially effective in dryer climates, but can also be applied in other climates. We can compute exactly what the cooling efficiency is and how much cooling you will need, based on our thermodynamic knowledge and Computational Fluid Dynamics modelling (CFD).

Greenhouse evaporative cooler

Two types of greenhouse cooling systems are available of which the working principles are based on evaporative cooling. The fan and pad cooling system and the fogging system or misting system. A big advantage of an evaporative cooler is that it operates without the use of CFC’s or HCFC’s, like air conditioning systems do. Also, compared to conventional air conditioning systems, evaporative coolers for greenhouses require about 70% less costs to operate.

Greenhouse fogging system

A fogging system may also be referred to a as a misting system or a spraying system. Humidity and its control is of great importance for a good greenhouse climate. By humidifying the air in the greenhouse, also called fogging, evaporation takes place and cools the air. This affects the humidity and ambient temperature.

Cooling the greenhouse without CO2 loss

As fogging allows for cooling the air, the air windows can be opened partially. This allows the CO2 level in your greenhouse to remain higher.

Adiabatic cooling

The evaporation of a crop requires energy. This energy is withdrawn from the greenhouse air. The energy in the form of heat is converted into water vapor. The energy is still there, but does not feel as heat. The crop can be helped in the conversion of sensible heat to water vapor using fogging. This is also known as adiabatic cooling.

By using a fogging installation the crop is helped with cooling. Therefore, less energy needs to be extracted from the greenhouse air. Adiabatic cooling is extremely energy efficient. The air in the greenhouse is cooled down by the evaporation of water. The lower the relative humidity, the higher the efficiency of the cooling process.

Fogging systems from Enerdes

Enerdes fogging systems consist of high-pressurized lines hung at the top of the greenhouse. The stainless steel high-pressure line has a branch every 2 to 3 meters with a special high pressure nozzle which will atomize the water to a very fine mist. Our systems of Enerdes are custom made and thus tailored to your requirements. Two systems are available:

  • Greenhouse high pressure fogger or high pressure misting system
  • Greenhouse low pressure fogger or sprayer

Fan and pad cooling system

Under certain circumstances, the recirculation of air in the greenhouse is not enough to create a perfect climate for the crop. In this case, air from outside is required. When outside air is drawn in, the use of cooling pads is the most efficient way to cool the greenhouse.

Cooling outside air with cooling pads

By using Cooling pads, the ambient temperature can be significantly lowered. The quantity and size of the cooling pads that you will need, depend on many factors. The optimal growing temperature, outdoor climate, the kind of crop and environmental conditions are important factors to take into account.

Wet wall greenhouse

Above the cooling pads is a water supply to distribute water onto the pads. On top of the cooling pad is a glued distribution pad which spreads the water evenly across the pad. In that way, the cooling pad is evenly moistened. Water drips down through the honeycomb structure of the cooling pads. The hot outside air flows through the cooling pads and is cooled down by the wet surface, hereafter the cooled air enters the greenhouse. Under the cooling pads is a drain which collects the water and makes it suitable for re-use. A wet wall greenhouse is created, but no water is wasted in Enerdes climate systems!

Greenhouse cooling pads from Enerdes

Enerdes has found a solution to increase the firmness of cooling pads and thus to extend the life. The special cooling pads are fitted with frames. By this development, the cooling pads stay in place better and are less sensitive to external influences and construction. This makes them universally applicable. Both the cooling pads and the frames are custom-made and are therefore available in different sizes. The cooling pads of Enerdes make the greenhouse climate suitable for your plants, even in the hottest months. The pads are not harmful to the environment and require minimum maintenance.

The cooling pads with frames are sold separately for existing greenhouses, but also with water distribution units: 

Greenhouse coolings pads Enerdes 3
Greenhouse cooling pads Enerdes 2
wrong constructed Greenhouse coolings pads

Pad cooling system life time

There are several factors that affect the lifetime of cooling pads, including water treatment (pH and EC value), wind influences, the cleaning cycle, drying after use and intensity of use. Also the way of construction the cooling pads is of great influence. Cooling pads can warp by these influences or fall out of the wall. Enerdes cooling pads are constructed for long product life time and we can advise you on how to sufficiently cool your greenhouse, while maintaining your cooling pads in a good condition.

Enerdes greenhouse cooling fans

Enerdes is also the exclusive supplier of greenhouse fans that are suitable for

  • Greenhouse ventilation
  • Air circulation
  • Fan and pad cooling systems
  • Fogging systems or misting system
  • Air intake and air exhausts for greenhouses

Enerdes chilled water cooling in greenhouses

During summer periods, many greenhouses revert to ventilation and evaporative cooling to get their greenhouse to the desired temperature. However, in warm and humid climates, it is not possible to cool down the greenhouse sufficiently with evaporative cooling. Other technology must be used, namely, active cooling. This cooling technology can be compared with air conditioning, but on a really big scale.

Chillers are used to provide active cooling for industrial greenhouses. Enerdes can develop an installation for greenhouse cooling using chillers and air handling units that are optimized for your climate and have minimal energy consumption.

The demand for industrial greenhouses in warm and humid climates, like in Asia, is growing. It is not possible to sufficiently cool greenhouses in these climates with conventional technologies like ventilation and evaporative cooling, because the air is already almost completely satisfied with moisture. Somehow, the moisture must be removed from the air and the air must be cooled down in order to reach the desired temperature and humidity levels in the greenhouse. This can be achieved by integrating greenhouse cooling using chillers and air handling units. The chiller provides cold water  and the air handling units cool and dehumidify the air.

Greenhouse cooling alternative by Enerdes

The investment costs and operating costs of an active cooling installation can become really high if the system is not well engineered. Enerdes is specialised in greenhouse climate control. Enerdes analyses and models your greenhouse and the thermodynamics of the indoor climate that you would like to realise. Based on the following factors, we determine the heating and cooling demand that your greenhouse will have during the year:

  • Outdoor climate in all seasons over the last few years, including exceptional weather events.
  • Desired indoor climate
  • Plant type and Plant evaporation production
  • Heat production by lights and other machines
  • Type of greenhouse, volume, area, roof and wall type.

If the resulting cooling demand cannot be accomplished with conventional cooling mechanism, an active cooling installation is designed. This can be based on water cooling, this will provide chilled water with a minimal temperature of 4°C. Alternatively, a glycol solution can be used which can be cooled to temperatures far below 0°C! The choice and the design will be based on the cooling demand and the energy costs.

Generally, a chilled water cooling installation developed by Enerdes is most suitable for cooling an industrial greenhouse.

How greenhouse cooling works

A chilled water cooling installation consists of a chiller and a piping network. Chilled water is transported throughout the greenhouse in a loop to provide cooling. The process during which water is used as the heat-transfer medium is called hydronics, in this case to provide cooling. Using valves, the piping network can be divided into several groups, so the greenhouse can be segregated in several areas in which the temperature is controlled separately. Individual temperature zones are assigned in the greenhouse.  The air handling units together with the chiller provide optimal greenhouse temperature and humidity conditions.

In the air handling unit, a fan draws warm and humid  air past a heat exchanger with the chilled water, the cooling coils. The air is cooled and the moisture condenses. Cool and dry air is spread into the greenhouse. The temperature in the cooling coils is regulated with temperature sensors and valves and variable fan power influences the amount of air that is cooled. This allows precise climate control in the greenhouse.

Precise Greenhouse cooling control

A chilled water cooling installation for greenhouses offers very precise control over your greenhouse temperature and growing conditions. Enerdes provides can also provide well designed control technology that contains robust control PID, that will smoothly operate all components in the installation in order to achieve the perfect greenhouse climate. Components that are monitored and controlled are:

  • Chiller power and output temperature
  • Temperature and RH sensors in the greenhouse
  • Greenhouse Piping and valves
  • Air handling units and their fans
  • Temperature sensors in the piping and air handling units

By meticulously controlling the valves and fans, the desired greenhouse temperature and humidity can be achieved to very accurate level and the automated control allows energy and cost savings!

Customized Enerdes greenhouse cooling solutions

Enerdes optimizes every greenhouse cooling installation to the unique requirements and conditions of the customer’s greenhouse. Together we will look into how we can achieve a robust climate control solution that will provide your greenhouse with appropriate cooling with minimal operating costs. When selecting a cooling installation it is important to keep the following in mind:

  • Cooling demand
  • Indoor and Outdoor climate conditions
  • Stability and reliability of proposed climate control mechanism
  • Maintenance requirements
  • Capacity of cooling installation
  • Greenhouse area, volume and shape
  • Energy consumption
  • In case you wish to use a cooling medium colder than 4°C, safety regulations of medium and freeze prevention.
  • Cooling installation dimensions and delivery time.
  • Installation costs
  • Operational costs

Enerdes can provide you with a complete climate control systems, or parts of it, like:

  • Chilled water cooling installation
  • Greenhouse chiller
  • Greenhouse cooling piping
  • Greenhouse cooling pumps
  • Greenhouse valves
  • Air handling units for cooling a greenhouse
  • Greenhouse fans for cooling
  • Climate control sensors
  • Control technology for greenhouse cooling
  • Air distribution hoses

Enerdes Chilled water system for greenhouses

Greenhouse cooling using chillers has several advantages for greenhouses:

  • Precise temperature control in your greenhouse.
  • Precise humidity control, moisture removal from the air.
  • Suitable for any outdoor climate.
  • Separate temperature and humidity zones that are controlled individually possible.
  • Minimal to no introduction of external air, if this is undesirable.

Enerdes cooling installations will keep your plants healthy and allow you achieve higher yield! It is also possible to combine a chilled water cooling system with an evaporative cooling system that is active in less humid periods and a heating systems that heats your greenhouse during colder seasons. This will give your optimal control over your growing conditions and will save energy and water consumption. Enerdes can advise you on which climate control installation in most suitable for you and what capacity you will need. We make sure you have sufficient cooling and heating capacity without making unnecessary investments by buying to much air handling units or units with redundant capacity. 

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