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GEA Grasso heat pump maximizes energy efficiency for orchid cultivation

A greenhouse is heated by an ammonia heat pump and with green power – without CO2 emission

The challenge in terms of sustainability:

The specifications of the operators of a new greenhouse stated that the required tem-perature must be perfectly maintained throughout the entire year without the use of natural gas – and that an exact temperature balance must be maintained between the two zones of the greenhouse.

The initial situation:

Van der Hoorn Orchids in Ter Aar (Netherlands) must maintain two climate zones for cultivation of exotic orchids in its 15,000 m² greenhouse. A temperature of 28 °C must prevail in the first zone where the young plants grow for 26 to 32 weeks. In the second zone, at a temperature of 19 °C, the mature plants remain for 18 to 24 weeks until full bloom. Ground water taken from a depth of 80 to 100 m is to be used for heating and cooling of the entire greenhouse.

The solution:

An electrically powered compression heat pump provides energy to heat the green-house. Similar to the compression refrigeration principle (that is also used in household refrigerators), a refrigerant cycle operates in the heat pump and in various process steps compresses, condenses, decompresses, and evaporates the refrigerant. In these steps, heat is removed from a medium on one side of the heat pump (i.e., at Van der Hoorn Orchids, from the ground water) and is released on the other side (here, to the hot-water cycle). This raises the temperature of the heating water to around 50 °C.
The heat-pump system provides hot water to a 400-m³ buffer storage unit, which then supplies the heating system. On the basis of the large hot-water storage unit, it is possible to chronologically decouple heat supply and demand, which enables the orchid grower to take advantage of low power prices outside peak-demand times.

The ground water, slightly cooled by heat pump operation, is stored in a so-called aquifer system, a geothermic ground water reservoir. In summer, the greenhouse is cooled by cold water from the aquifer system (total capacity of the aquifer: 180 m³/h).
The heat pump functions with ammonia, a natural refrigerant, which has no ozone-depletion potential and does not contribute to global warming. Thanks to its material characteristics, ammonia is one of the most efficient refrigerants. The greenhouse can operate without natural gas, but not without electricity. Orchid breeder Van der Hoorn Orchids accordingly powers the heat pump with electricity from renewable energy and thereby achieves maximum climate protection.

The sustainable strengths:

Heat pumps from the GEA Grasso FX GC PP series achieve excellent performance levels, even at partial load. The use of two piston compressors (GEA Grasso 810 as well as GEA Grasso 612, with speed control by a frequency converter) results in out-standing coefficients of performance (COP). The special characteristics of ammonia heat pumps are ideal for this project. The great efficiency of heat production appreciably reduces CO2 emissions in comparison to production of heat in a natural-gas boiler. Thanks to the use of green power for driving the heat pump, orchid breeding at Van der Hoorn Orchids is even climate-neutral.

The inventors :

The Dutch company Van Zaal Niederlande developed this system jointly with GEA Refrigeration Technologies.
GEA Refrigeration Technologies, part of the internationally active GEA Group, is synonymous for industrial refrigeration technology. Beginning as early as the late nineteenth century, it has been our business to cool processes and products and to control the temperature of transported goods. Our solutions can be found in the food and beverage sector; in the petrochemical, chemical, and pharmaceutical industries; on fishing ships; in natural gas liquefaction; in infrastructure facilities; and in ice factories. We also know what it takes to refrigerate leisure facilities. For us, refrigeration has been a passion for decades. Our colleagues are therefore at work with enthusiasm in development and production, as they also are in the maintenance and service of your refrigeration systems.

Brief profile of the company:

Name:  GEA Refrigeration Technologies
Home office:  Bochum (Germany)
Founded in: 1896
Workforce:  3,147
Solutions provided:  refrigeration components and solutions for industry
Scope of activities:  international