Get the most out of your environmental control systems

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An Integrated Environmental Control System (ECS) is the best tool you can have for making science-based growing decisions, hands down. Integrating all your equipment into one system, not only your temperature and humidity controllers, but also lighting, water treatment, irrigation, CO2 enrichment systems and alarms , provides better data, tighter control, increased energy savings and reduced waste.

Some systems will analyze your harvest statistics and record work tasks to improve productivity. These systems use look-ahead logic to make predictive changes to your climate, which is especially important in a dynamic greenhouse environment where sunlight changes every few minutes on a partly cloudy day. This allows you to focus on growing your crop rather than worrying about your climate. For example, while non-integrated equipment may require several adjustments per day as conditions change, the greenhouse my team managed only needed adjustment seasonally (four times a year).

ECS stores and displays data to allow you to fine-tune your programming. They notify you if there is a problem via sound alarms and call SMS, e-mail or phone calls. Finally, with experience, a grower can learn to diagnose equipment problems using data graphs, often long before an alarm condition is reached. Because of their ability to amplify the skills of a good grower, I recommend my colleagues invest in the best ECS system they can afford.

Here are some tips for getting the most out of this essential tool:

1. Perform routine equipment checks.

The curse of all automation is the complacency it breeds. Unlike the fail-safe engineering of an airplane, the ECS does not have a sensor on every piece of greenhouse or grow room equipment indicating that it is working. It sends the signal to turn it on or off, but that’s all it knows. It’s up to you to make sure the fresh air damper actually opens and closes or that the greenhouse’s exhaust fan hasn’t slipped off a belt and is no longer spinning. It is essential to train personnel to recognize malfunctions and carry out routine maintenance checks.

Photo courtesy of Rob Eddy

2. Don’t skip training.

Too often, even though you’ve been offered a number of hours of free training on your system, in the rush and excitement of starting a new installation, that training is dropped. This is especially true when you realize how little these systems require daily entries. Other times the seller may not provide it voluntarily unless you insist. Put this training on the calendar, let everyone know its importance, and try not to be interrupted during it.

3. Build lightning protection.

When lightning struck my ECS’s outdoor weather station, the load traveled down the wires to the individual greenhouse controller the weather station was wired to and fried it. Luckily, the charge didn’t travel further upstream, destroying the others, as a failsafe was built in. Inexpensive communication chips were designed to fail when overloaded, protecting other controller boards.

4. Plan future equipment.

When designing your system, provide at least one spare standard electrical outlet controlled by the ECS. This will allow you to quickly add equipment later, like an extra dehumidifier, or maybe something that hasn’t even been invented yet.

5. Add ECS to your preventive maintenance schedule.

Create a maintenance plan and assign responsibilities to it. If the fans that suck in your sensor boxes fail, the sensors will measure higher than room temperature as the lights or sun warm the box. If your system uses wet wicks to measure humidity and those wicks dry out or become covered in biofilm, they will not measure correctly. Grime on the glass thermistors that measure temperature/relative humidity (RH) affects the reading. Weather stations must be calibrated and verified; I once had rain inside an electronics board that was supposed to be sealed for an outdoor humidity sensor, causing inaccurate readings.

6. Don’t wait for the sensors to fail.

When certain temperature probes fail and signal is lost, they will often cause an alarm condition reading such as -40°C, letting you know exactly when it is happening. However, I have often observed that the sensor reading freezes on the last measurement and the room continues to heat up or cool down as it was at that time, until it gets too hot. or too cold and there is no more alarm! For this reason, I chose to replace my sensors every two years, even though they rarely, if ever, needed calibration until the day they stopped working.

7. Use static discharge strips.

When working on circuit boards, such as wiring new sensors or changing chips for a software upgrade, always wear a static discharge band around your wrist and attach it to ground in the cabinet. Without this protection for the equipment, you may not even see or feel the static spark, but damage resulting from a “ghost in the machine” is difficult to troubleshoot.

8. Study your climate charts carefully.

Understand what the normal looks like, in order to better understand the abnormal. You may think that troubleshooting problems is just about observing the actual equipment, but some problems only occur in certain weather conditions, which are hard to replicate. Some problems arise invisibly, such as when a heating valve in my facility malfunctioned. It never resulted in an alarm condition, and it’s unlikely a human could have observed or felt it, but the temperature was poorly controlled.

9. Create a troubleshooting workbook.

In the event of a malfunction, print a copy of the graph, indicate what the problem was and how it was solved, and create a troubleshooting workbook. Until I learned how to do this, I would find myself looking at a graph and knowing that I had seen this problem before, but couldn’t remember what it was.

10. Dial it.

The real power of the built-in controls is in the fine-tuning of the environment. With an understanding of programming and careful observation of climate data, you will be amazed at what you can accomplish. We had a researcher doing significant additional research on lighting, requiring the same daily integral light, or accumulated light, in the greenhouse through all seasons and weather conditions in our Midwestern US location, where it naturally varied from 2 mols/m2/day to 50 mols/m2/day. Using two layers of shade curtains and smart light control, we were able to “dial” a DLI of 12 every day with an error of just under 2 mol/m2/day.

By properly understanding how climate affects plant physiology, growers can use data from an ECS to refine optimal environments or even apply controlled stresses to achieve their production goals. Similar conditions can be maintained crop after crop, season after season, for predictability and uniformity of plant attributes. Graphical tracking and user expertise help troubleshoot and fix mechanical or programming errors that can linger for weeks or months without anyone knowing. The anticipatory logic and rapid cycle capability of these systems literally makes the difference between responding to environmental conditions and creating those conditions.

Rob Eddy is a greenhouse consultant and owner of CEA Consultancy based in West Lafayette, Indiana; [email protected]

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