In the UK you could try:
Watermiser Ltd,
Tower Works
Stoneygate Road
Newmilns
Ayrshire
KA16 9AY
Tel. No. +44 (0)1560 320762
Carter Environmental Engineers Ltd
Hamilton House
2 Lawley Middleway
Birmingham
England
B4 7XL
Tel. No. +44 (0)121 250 1000
SPX Cooling Technologies UK Ltd
Gregory's Bank
Worcester
WR3 8AB
UK
+44 (0)1905 720 200
Another company we've used but I don't have the details for are, Baltimore Aircoil.