How to design the assimilation lighting system of your greenhouse ?

1. Design your assimilation lighting system with Hortinergy

Assimilation lighting is increasingly being used for crop such as cannabis or tomato. However investment is very high and running costs are expensive.  Choice between HPS (High Pressure Sodium) and LED is not easy: HPS requires less investment but electricity consumption is higher and more heat is generated.

Hortinergy helps you to design your assimilation lighting system with an optimal climate for any project all over the world. You will be able to define the best equipment configuration to reduce your energy cost.

Supplemental lighting design Supplemental lighting design in Hortinergy

Hortinergy is a very friendly software:

  • You enter on-line the input parameters: lighting specification, regulation setpoints, transparent cover…
  • Hortinergy models solar transmission, assimilation lighting and inner climate during one year,
  • Hortinergy simulates energy consumption: heating, cooling, dehumidification.

Then you can assess the impact of many parameters and compare scenarios.

2. Input parameters to define the lighting system

Input parameters are:

  • LED and HPS specification: lighting intensity, efficiency…
  • Regulation setpoints:
    • Day Light Integral (DLI) and minimum hours of ‘’night’’ per day,
    • or fixed monthly schedule,
    • above which solar radiation intensity lighting is switched off,
  • Greenhouse transparent cover specification,
  • Black out and shading screen specification and their regulation setpoints,
  • GPS position to generate a weather file.

An example is shown below:

Supplemental lighting design with Hortinergy, a greenhouse software design
DLI settings for supplemental lighting design with Hortinergy

You can also define the blackout screen and its regulation setpoints as shown below.

lighting assimilation demonstration

3. Results

Hortinergy simulates your project during one year like a virtual greenhouse. Outputs are :

  • Solar radiation transmitted by the transparent cover and reaching canopy,
  • Assimilation lighting required according to regulation setpoints (mol/m²/day):
    • Day Light Integral (DLI),
    • or fixed monthly schedule,
  • Electricity consumption,
  • Impact on the inner climate and energy consumption: heating, cooling, dehumidification.

The reports are:

  •  a pdf document with typical days and monthly summary tables
  •  an Excel file with hourly data for deeper analysis.

Solar radiation reaching canopy and additional assimilation lighting required

Hortinergy simulates on hourly basis the solar radiation reaching canopy and the supplemental lighting required to reach the DLI.

The example below shows a monthly summary.

Addition assimilation light greenhouse design cannabis

Impact on the inner climate and energy consumption (heating, cooling, dehumidification)

Hortinergy models the impact of assimilation lighting on the inner climate and energy consumption (heating, cooling, dehumidification).

The example below shows the crop transpiration and a higher inner temperature when HPS assimilation lighting is switched on from to 9 to 11 AM and 4 to 9 PM to reach DLI.

assimilation light results

Electricity consumption and expenditures

Hortinergy shows also the electricity consumption and expenditures.

Electricity_consumption assimilation light cannabis greenhouse design

Hortinergy was developed by Agrithermic in partnership with the CTIFL (French Interprofessional Technical Centre for Fruit and Vegetables) and Astredhor (Institute of Horticulture Technology), the Agrocampus Ouest and the lycée agricole de La Cote saint André (CFPPA) in La Cote Saint André.

With Hortinergy, you can also design  semi closed greenhouse and test different settings so that you can optimise climate and energy consumption of your greenhouse project.  In hot and wet climate, closed greenhouse is an interesting option to achieve an optimal climate.

Hortinergy is an online paid software. You can choose your offer , create an account and then start your project.