The Broadlands Lucerne Company was formed in the early seventies to process the Lucerne alfalfa crop grown in the Broadlands area. The growing season is from November until the end of April and is harvested by cutting with a rotary mower, windowed in the field, then gathered by a conveyer for transport to the drying plant. It is important to dry the crop rapidly in order to retain the Vitamin A and protein and produce a hard, heavy pellet of bright green colour, an important selling feature. The plant is located on the Broadlands Geothermal Field and uses the steam from BR27, about half a kilometre away, which is reticulated via a two-phase transmission line. The steam is separated from the water close to the plant and piped into finned tube heat exchangers.
Air is forced through the heat exchangers by a centrifugal fan.
The Company now has to pay for its steam and has negotiated a price contract with the Government for the purchase of steam up to a maximum of 18 tonnes per hour. This paper analyzes the existing drying plant to determine the efficiency utilization and cost of energy use per unit of production. Further studies are reported of possibilities for energy savings both in the existing plant and in the future development which will incorporate a second drier and will treble the output.