Humidification systems for spaces have been available in the market place for many years. One such system for example involves one or more foggers of the type which are supplied with pressurized water and air as described for example in the U.S. Pat. No. 5,525,268. In the '268 patent a standard control system for supplying humidification is described using foggers that require pressurized air and water. The air pressure is kept at a higher fixed differential pressure to that of the water pressure. The control is capable of delivering a precise regulation over the humidification of the space. In such system for a large installation a large number of foggers are arranged in an array across an air flow inside an air handler and the humidified air is distributed to the particular areas that need to be humidified. Humidification has been proposed to be done either in the air handler or in the supply air or return air ducts.
The large air handler, typically used in large industrial or commercial facilities, is part of an air conditioning system having, inside a main air handler unit, both cooling and heating coils, dampers, a fan and appropriate controls to regulate the heating or cooling as required. In smaller home type central air conditioning systems air from a smaller air handler is distributed through supply ducts to the various rooms in the house and return air passes through return ducts to the small air handler. Frequently, several such small air handlers, each for a separate zone, are used for a house depending upon the most economical way to distribute the conditioned air. Typically, the air handlers include both heating and cooling coils for the different seasons.
Various schemes have been proposed to humidify a home. Sometimes the central air unit is provided with a source of steam or spray or fog or sometimes individual fog emitting units are used and some rely on piezo-electric devices. The individual units are placed in the rooms to be humidified and can work satisfactorily for that particular space, though care must be taken to maintain the cleanliness of the device, avoid the use of highly mineralized water and prevent the build up of bacterial build-up from standing water.
When an entire house is to be humidified, it would be more practical to use the available ducting to distribute humidified air. Spraying inside a standard sized duct, however, can lead to undesirable condensation of inside walls of the ducts and thus a pooling of water. Many current systems have reservoirs of water that are potential breeding grounds for microbial growth. Standing water thus can lead to health problems and as a result humidification through central air units in a house has not generally been satisfactory. Nor have conventional air humidification systems been found to be sufficiently reliable and practical for residential and small commercial applications.
Humidification of a home is well known to have significant benefits such as better air for breathing and nasal passages, reduction in the spread of airborne viruses, prevention of damage to wood furniture or floors and other articles from excessively dry air during winter time and a certain amount of scavenging of undesirable air components, such as spores, molds, chemicals and the like as these are either entrained or chemically altered and then removed by filters in the central air unit.
Humidification of air requires a source of water and for the above described system in the '268 patent a supply of pressurized air to deliver an adequate quantity of fog to humidify an air stream. When the water source includes a large quantity of minerals, as is often the case for homes relying upon artesian wells, the use of this water can lead to a clogging of the fogger head in some cases and the injection of these minerals in powder form into the home. This injection tends to be undesirable and can be unhealthy but is particularly onerous by leaving a fine film of dust on all surfaces throughout a house. One known technique used to remove minerals from the water involves a reverse osmosis filtration device with which the minerals can be sufficiently removed to provide a clean source of water for air humidification.