First the easy one, PET is what water bottles are made from. Second is you are in a good location for wet pads to work. Here in Florida they don't do much to cool in summer since the humidity is already in the 80% or higher range on many a summer day. In areas with low humidity they work by evaporating water as air is passed over them, as the water evaporates it cools the air, hence the more specific name of "evaporative coolers". There are two basic types Aspen Pads (which is what the PET type are) and Cool Cell which are made from a specially designed fibre that has an engineered airflow pattern to maximize the evaporation without compromising the airflow. Aspen Pads and similar are just that, pads of Aspen strings held inside some type of mesh that water is dribbled over. Most that I have seen tend to have holes and gaps in the pad and places where it is thicker than you would wish restricting airflow. The typical installation has one wall of the greenhouse that is the pads with exhaust fans on the opposite wall. If you are subject to frequent power outages as we are you better have a good emergency backup generator that comes on automatically because for them to work all air must be pulled through them, meaning if the fans go out on a hot sunny day you can have some nice cooked orchids in no time. Swamp coolers are not quite as bad as they are generally self contained units that can do some good in a passive cooled greenhouse. I have learned to prefer high pressure fog for cooling and humidifying since they work whether the greenhouse is open or closed. -----Original Message----- From: Paul Carver [mailto:[EMAIL PROTECTED] Sent: Wednesday, February 27, 2008 01:54 AM To: [email protected] Subject: [OGD] Wetpads
Wet pads: Here in Melbourne Australia, I know of only one grower who uses wet pads for cooling & humidifying. This system is a mystery to me, but I have to acknowledge that a much higher % humidity can be achieved than with my small swamp coolers with supplemental misters. Would somebody please explain the 'system' , and where I can resource the 'hardware'. Here we can have hot summer days to 40 deg.C (100F), with humidity as low as 20%. It is a constant struggle in summer to ensure constant high humidity when temperatures go to 100d. F . What are recycled PET pads? Paul, Oz. _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
