ErfGoed’s innovative Airflow system has demonstrated significant potential for both energy savings and enhancing crop quality through lower temperatures. Recent measurements and tests conducted with the Airflow system have yielded positive results, showcasing its promise. However, further research is required to explore its full capabilities.
The Airflow system comprises an ebb-and-flow floor that incorporates heating and cooling elements via hoses beneath the floor. Additionally, the system introduces air through distribution tubes within the floor to regulate the ambient temperature around the crops. These tubes are equipped with perforations to facilitate air distribution through the porous floor, making the system unique in its approach.
ErfGoed conducted comprehensive trials of the Airflow system at its Moerkapelle site, focusing on a Sarcococca crop. Leo de Rijke, an adviser from De Rijke Techniek, played a pivotal role in overseeing the measurements and analyses. “We monitored pot, floor, and room temperatures,” De Rijke explained. “Comparing a department with an innovative Airflow floor to a ‘normal’ department with a standard ebb-and-flow floor from ErfGoed under identical conditions, the added value of the Airflow floor became evident.”
Unlocking the Potential of Low-Grade Heat Part of the study aimed to evaluate the effects of heating using the Airflow floor. Low-grade heat at 35 degrees Celsius was supplied via the hoses, and air was introduced into the floor, distributing through the floor via a specialized system. De Rijke observed, “Introducing air allowed us to cool the low-grade heat back to a temperature of 22 degrees Celsius. Without air input, the return temperature reached 27 degrees Celsius. This innovative approach enhances the efficiency of utilizing low-grade heat, as the floor’s heat exchange capacity increases with air introduction.”
Opportunities for Energy Efficiency De Rijke noted that this efficiency offers energy-saving opportunities and may be of particular interest to growers employing geothermal heat or heat pumps. “While we introduced low-grade heat via the boiler during the trial, geothermal heat or heat from a heat pump can also be used,” he explained. “Growers can choose to either maximize cooling efficiency or reduce supply temperature, ultimately conserving energy required to maintain greenhouse temperatures. The exact energy savings will be determined in further research, but this approach enhances the overall efficiency of heat pumps or geothermal heat sources.”
Enhanced Cooling on Hot Days Extensive testing was also conducted on cooling the Airflow floor through hoses combined with introducing cold air. This cooling method demonstrated clear advantages on hot days. De Rijke stated, “The temperature between the crop in the section with the Airflow system was approximately five degrees Celsius lower on average than in the section with the regular ErfGoed floor. This result was achieved by introducing cold water through the hoses and cold air precisely where it is needed.”
Lower temperatures significantly benefit crop growth, according to Cor Bremmer, Commercial Director at ErfGoed. “Maintaining temperatures between 20 and 30 degrees Celsius optimizes crop growth. The increased relative humidity resulting from dry airflow absorbing moisture from the floor promotes stomatal opening and photosynthesis. Moreover, improved air circulation benefits plant growth and enhances the microclimate around the plants.”
Ongoing Research Both heating and cooling with the Airflow system demonstrate clear advantages, but their suitability depends on a grower’s specific circumstances and location. De Rijke noted, “Cooling with the Airflow system may be particularly appealing to growers in warmer regions. These are aspects we will further explore in subsequent trials. Many questions remain, including the feasibility of system investment and its potential payback period. Nevertheless, the Airflow system undoubtedly holds substantial promise.” New trials are scheduled to take place at ErfGoed and among several customers in the field to continue assessing the system’s capabilities.