Invention of the semi-closed greenhouse

The semi closed greenhouse has been invented by Casey Houweling of Houweling’s Tomatoes and Geurt Reinders of Enerdes Sustainable Energy Solutions. The first pilot has been built in 2005 in the Houweling’s greenhouse in Camarillo California. The basics of the system were 35 axial fans blowing in outside air (through cooling pads) into an air distribution hose in order to distribute air and create an overpressure in the greenhouse. This project was called “Forced Greenhouse Ventilation & Cooling”.

Forced Greenhouse and Ventilation
Camarillo Greenhouse Houweling's

The semi-closed greenhouse: from pilot to patent

The pilot was very successful and led to the patented principle “Forced Greenhouse Ventilation & Cooling” (inventors C. Houweling and G. Reinders). See our patent page for more information. Houweling Tomatoes invested in 2 blocks of 8ha. with this system. The first block was finished in 2009, the second in 2010. For these blocks, Enerdes developed special air handling units called AHU2HECR630. In total 747 air handling units have been installed in the Houweling’s Nurseries facility in Camarillo.

Air handling units during construction
Geurt Reinders near flue gas ducts

Houweling’s semi-closed greenhouse in Mona

In 2015 Houweling expanded the semi closed greenhouse principle to Mona in Utah. This new greenhouse makes use of the latest state of the art technology. Together with Enerdes, Houweling built a 11ha. greenhouse attached to a power plant. Houweling extracts the free heat and CO2 from the power plant for the use in the greenhouse. The entire 11ha. greenhouse has 496 air handling units installed (AHU1VECR710).

Read more about Houweling’s unique greenhouse in Mona, Utah.
Flue Gas Duct Houweling's Utah