Improving energy efficiency by heating greenhouse crops with microwaves

The greenhouse vegetable industry is very energy and CO₂ intensive. Heating greenhouse crops with microwaves offers potential improvements in energy efficiency of at least 50%. Furthermore, the efficiency of a microwave crop heating system compared to a conventional system is largely dependent on the plant mass and the volume that it occupies. Presented here are results confirming plants can be grown successfully, and to similar standards as conventionally heated plants, using microwave heating. Furthermore, the performance of the plants is a function of the resultant temperature and the uniformity of the heating pattern within the plant. Heating uniformity can be improved dramatically by using circularly polarized incident electromagnetic fields. Providing power requirements can be met, microwave heating results in similar growth characteristics as conventionally heated plants.