Huge saving
September 1st 2005 Dairy Crest is a large steam energy user, and its steam boilers represent a major element of the site’s £1.8m annual utilities bill.
An energy saving opportunity was identified with the low pressure boiler. Rated at 4230kg/h, this boiler was supplying an average of 2200kg/h, only 52% of its capacity.
Craig Pepworth, electrical engineering manager considered reducing the size of the boiler burner to match the steam load, that would have let them reduce the size of the forced draft fan motor. However, steam demand would increase over time so any reduction in boiler capacity was ruled out.
The solution was to fit a new electronic fuel control system and a Danfoss variable speed drive to the forced draught motor. These simple retrofits would improve control of the fuel/air ratio. The drive speed is regulated by a 40- 20mA signal from the direct digital combustion controller (DDCC) and the drive provides a 4-20mA feedback signal to the DDCC.
Following installation Dairy Crest saved 47 000kWh per annum representing energy savings of £1800 and 5.52t of carbon. More articles from Danfoss Limited: | 
