1. Field of the Invention
The present invention generally relates to an air conditioning system, such as for use in cooling and heating rooms or similar compartments, and more particularly, to an air conditioning system which heats and cools by radiation. Air conditioning system, as used herein, refers to a system that both cools and heats rooms. Such a system may include what is commonly known as a heat pump type of air conditioning system.
2. Description of the Prior Art
Generally, a conventional air conditioning system used in a house or similar dwelling cools the rooms in the house or dwelling in a cooling mode of operation, by supplying a forced flow of cooled air from an indoor unit of the system. However, such a forced air cooling operation often supplies uncomfortable drafts of cool air to the people in the rooms. In contrast, some conventional air conditioning systems may be structured to heat rooms by radiation (i.e., radiant energy heating) to prevent supplying uncomfortable drafts of heated air into the rooms. For example, an air conditioning system may be adapted for radiant energy heating, whereby a radiation surface is formed under or on the surface of a floor, and pipes that circulate high temperature refrigerant from a compressor operating during a heating cycle are arranged on the radiation surface. Conversely, cooling of air in these rooms may also be accomplished by radiation (i.e., radiation cooling) by reversing the flow of refrigerant in such an air conditioning system, whereby the pipes arranged on the radiation surface circulate cooled refrigerant during a cooling mode of operation.
Nevertheless, conventional air conditioning systems experience a significant problem if radiation cooling is attempted utilizing a similar structure to that used for radiant energy heating. That is, since the radiation surface is heat exchanged directly by the cooled refrigerant, the humid air surrounding the radiation surface is condensed into dew or droplets of water onto the radiation surface. This water can freeze on the surface and substantially reduce the cooling efficiency of the system. Consequently, even if a conventional air conditioning system may be capable of heating rooms by radiation during a heating mode, such a system is still required to cool the rooms by blowing cool air into the rooms during the cooling mode of operation.