Optimizing cultivation with a 24-hour temperature strategy

The 24-hour temperature strategy is not yet being applied by all Priva Connext users, but for both vegetable and ornamental cultivation it really is a control module that makes it easier to achieve production or planning objectives.

During the day there are circumstances that you cannot avoid as a grower, such as radiation, lighting that comes on, or perhaps a rain shower. This can cause the greenhouse temperature to deviate from the desired 24-hour temperature. To achieve the desired 24-hour temperature, it is necessary to compensate at other times of the day.

Ornamental plant cultivation

In ornamental plant cultivation we see that growers like to have control over the cultivation period. The daily temperature determines this to a large extent. With the 24/7 temperature strategy it is possible to set the average temperature over a 24-hour period.

In the 24-hour temperature strategy screen in Priva Office, the temperature range within which the control can compensate can be set for each period. After a deviation, the control fully automatically distributes the compensation over the remaining hours of the 24-hour period. An example: if there are five hours left in the 24-hour period and there is a deviation of 1 degree from the 24-hour temperature, compensation will be made at 0.2 degrees per hour. Martin van der Mei, gerbera cultivation consultant, endorses the benefit of the scheme:

"On gerbera farms, this control module is widely used. Virtually all gerbera growers have a PAR meter. Consultancy company Flori Consult Group has developed a table for gerbera cultivation from which the optimal 24-hour temperature can be extracted that corresponds to a certain PAR sum and daily CO₂ value. This is how a gerbera grower knows how to keep his crop in balance."

- Martin van der Mei, consultant at Flori Consult Group.

The image below illustrates how the 24-hour temperature strategy works. In this situation at a gerbera grower, the 24-hour temperature depends on the radiation sum. With a higher radiation sum, a higher 24-hour temperature is therefore calculated. This is clearly visible in the example. The second day is a lighter day, with a higher radiation sum.

The 24-hour period starts at 06:00. It can be clearly seen that the actual 24-hour temperature (light green line) meets the calculated 24-hour temperature (dark blue line) at the end of the 24-hour period.

The red and the light blue line are the corrections made by the 24-hour temperature control to the heating temperature and the ventilation temperature. These values are adjusted to ensure that at the end of the 24-hour period the calculated 24-hour temperature is achieved.

Vegetable growing

Vegetable growers handle this differently. With vegetables, it is not about a fixed cultivation time, but about as much speed in fruit development as possible. If it has been very light, the plant has produced more sugar. Then the 24-hour temperature may be higher to accelerate the development speed of the crop and thus the production of new fruit.

It is possible to make the desired 24-hour temperature dependent on the radiation sum. If there is more radiation, the greenhouse temperature and thus the 24-hour temperature automatically increases. Depending on the realized daily temperature, compensation can then be done at night to finally reach the desired daily temperature.

When you use the 24/7 temperature strategy, the computer automatically compensates for the heating and ventilation default settings. You do not have to change these.

Advantages

The big advantage of the 24-hour temperature strategy is that you can control the average 24-hour temperature more precisely according to the needs of the crop. This makes it easier to respond to changing weather situations.

Specifically for ornamentals, planning is realized more accurately, with greater ease.

Within vegetable cultivation, the control ensures that maximum production can be realized. The radiation sum is the starting point.

Indirectly, the 24-hour temperature strategy can also lead to energy savings. For example, in spring, when it is still cool during the day the control can compensate more easily and cheaply at night by closing the curtain and keeping more heat inside.

For example, when the desired temperature is not realized during the day due to a combination of a limit on the maximum pipe temperature and unfavorable outdoor conditions. With the 24-hour temperature control, the temperature at night, when the energy curtain is closed, can be adjusted automatically to achieve the desired 24-hour temperature.

Unique control module

The 24-hour temperature strategy is unique to Priva Connext. The control module fully automatically controls the ventilation and heating temperature to achieve the desired 24-hour temperature. If the heating goes up, the ventilation temperature moves in parallel. If the calculated heating temperature is lowered, the ventilation temperature can either move with it or not. If desired, the temperature gap of the curtains can also be linked to the heating temperature and thus controlled indirectly.

If you want to use the 24-hour temperature strategy, it is important that heating, ventilation, and 24-hour temperature strategy are well aligned. Your Priva consultant can create a custom screen in Priva Office, which offers you all relevant information in one overview.