Van der Hoorn Orchids

Industry Segment



Van der Hoorn Orchids

Ter Aar Netherlands


It is no secret than the Dutch love flowers. In 2006 the orchid breeder Maurice van der Hoorn, owner and operator of Van der Hoorn Orchids, gave this passion an environmentally friendly face. In his new greenhouse in Ter Aar, near Amsterdam, his Phalaenopsis orchids thrive wonderfully – and without the use of natural gas. During the summer, a greenhouse acts as a giant solar collector. The fundamental principle developed by Van der Hoorn was to collect the summer heat, instead of blowing it out by fans, and to use it in winter. This became possible thanks to an electric driven heat pump supplied by GEA Refrigeration Technologies.

The temperature required by such exotic beauties depends on their size and their stage of growth. As a result, the required temperature on one half of Van der Hoorn’s large (15,000 m2) greenhouse annex is 20 °C / 68 °F, and 28 °C / 82.4 °F on the other half. Heating and cooling take part with support from ground water from a depth of 80 to 100 m. In the summer, the water from this level, at around 7 °C / 44.6 °F, is pumped to the surface to cool the greenhouse. It returns deep to the earth at a temperature of approx. 18 °C / 64.4 °F. The sunnier and hotter the weather, the greater the cooling requirements – and the more the cooling water is heated. During winter, the slightly heated water is pumped back to the surface to support heating.

Short description of the solution

The heating mode requires operation of the GEA ammonia heat pump. It has a rating of 1,500 kW at 6 / 50 °C / 42.8 / 122 °F. This heat pump operates mostly at night, outside peak-demand periods. It heats the boiler heating water to a maximum temperature of 50 °C / 122 °F and stores it in a buffer storage unit with a capacity of 400 m3, until the greenhouse requires this heat. In the heating mode, the heat pump cools the ground water to store cold water in aquifers – which then serves for cooling during the summer months.

As a result, the greenhouse can do without natural gas, but not without electric power. To achieve maximum climate protection, Van der Hoorn Orchids powers their greenhouses with electricity from renewable energy sources (wind energy and bio attenuation installations).

Key figures

Capacity in kW (at temperature level): 1.500 kW

Refrigerant: R-717 (NH3)

Secondary refrigerant:



Year of installation: 2006

Sign up to stay updated on Grade news

This site uses Cookies >