Air distribution system in a modern Phalaenopsis greenhouse; results of a 1-year monitoring project

Gepubliceerd op
27 november 2013

Wageningen UR Greenhouse Horticulture has conducted a 1-year monitoring project on the use of an air distribution system on a modern greenhouse growing Phalaenopsis. Such a system makes it possible to accept higher humidity’s and enables the grower to keep the thermal screens closed as much as possible. These two things are the main basis for the energy saving potential of The New Cultivation. The research was funded by the Product Board of Horticulture and the Dutch Ministry of Economic Affairs and was carried out as part of the Innovation Programme Greenhouse as Energy Source.

A prerequisite for effective energy is that the greenhouse climate computer settings are adjusted according to the new possibilities of the hardware installed. The widely used minimum pipe temperature settings should be drastically reduced, screens must be kept closed at higher outside temperatures and partial opening of the screen should be avoided.

Climate settings

During the course of the project, the climate controller setpoints were been adjusted step by step, resulting in a clear energy conservation result by the end of June. By that time the energy consumption in the departments with the air treatment units showed a more than 1 m³ per m² lower gas consumption compared with the reference.

However, from early August until the end of the monitoring period, the grower decided to use the air treatment to achieve a drier ‘active’ climate, rather than a low energy consumption. This in order to secure the high growth rate experienced in the previous months. Due to this change in the use of the system, the energy saving effect in the second half of the year almost completely disappeared.

Energy savings

The absolute savings at the end of the year amounted to 40 MJ/m². This is 2.5% of the annual consumption of 51 m³/m². If the climate control strategy used in spring had been continued throughout the year, the annual savings would have been 7%, which means a 4 m³/(m² year) reduction of energy use. The electricity consumption of the air treatment unit in the monitoring year was 1.6 kWh/m², but if the installation in the coming years will be used like it was used in the last six months, the annual electricity consumption of the air treatment unit will become 4 kWh/(m² year).