Greenhouse efficiency management model Wageningen UR

OMER: energy resources in greenhouse crop production

Greenhouse efficiency management model Wageningen UR
The optimal control does not need to maintain a minimum pipe temperature, in contrast to current practice.
When the minimum pipe temperature strategy of the grower was implemented, heating and CO2 were reduced by 28% and 10% respectively.

OMER: Optimal management of energy resources in greenhouse crop production systems

The project aims at supporting the greenhouse industry in achieving the agreed reduction in energy consumption and CO2 emission of 48% in the year 2020.

Saving energy in greenhouses is an important issue for growers. Here, we present a method to minimize the total energy that is required to heat and cool a greenhouse.

Supporting the greenhouse industry

Using this method, the grower can define bounds for temperature, humidity, CO2 concentration, and the maximum amount of CO2 available.

Given these settings, optimal control techniques can be used to minimize energy input.

Optimal Greenhouse Climate Management

Saving energy in greenhouses is an important issue for growers. Here, we present a method to minimize the total energy that is required to heat and cool a greenhouse.

Using this method, the grower can define bounds for:

  • temperature
  • humidity
  • CO2 concentration
  • the maximum amount of CO2 available

Given these settings, optimal control techniques can be used to minimize energy input. To do this, an existing greenhouse climate model for temperature and humidity was expanded to include a CO2 balance.

Heating, cooling, the amount of natural ventilation, and the injection of industrial CO2were used as control variables.

Greenhouse optimization

Standard optimization settings were defined in order to compare the grower’s strategy with the optimal solution. This optimization resulted in a theoretical

  • 47% reduction in heating
  • 15% reduction in cooling
  • 10% reduction in CO2 injection

The optimal control does not need to maintain a minimum pipe temperature, in contrast to current practice.

When the minimum pipe temperature strategy of the grower was implemented, heating and CO2 were reduced by 28% and 10% respectively.

Optimal energy input

We also analyzed the effect of different bounds on optimal energy input.

We found that as more freedom is given to the climate variables, the higher the potential energy savings. However, in practice the grower is in charge of defining the bounds.

Thus, the potential energy savings critically depend on the choice of these bounds. This effect was analyzed by varying the bounds. However, because the effect can be demonstrated to the grower, the outcome has value to the grower with respect to decision making, an option that is not currently available in practice today.

Link to the full report

Research

Wageningen UR

Prof. dr. ir. Eldert J. van Henten
P. 0317-483328

Timeframe

Oct. 2011 – Oct. 2015

 

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