Refrigeration – Automatic control – Selective heating or cooling
Patent
1988-05-16
1990-07-03
King, Lloyd L.
Refrigeration
Automatic control
Selective heating or cooling
623241, 622387, F25B 1300
Patent
active
049380320
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an airconditioning system and relates particularly, although not exclusively, to an air-conditioning system for providing a controlled temperature and humidity environment for an enclosed space.
The operation concepts of air-conditioning or refrigeration systems are well known. They consist of an evaporator coil, a condensor coil, a thermal-type expansion valve or capillary and a refrigerant compressor. The refrigerant is compressed by the compressor and the high pressure vapour flows to the condensor coil where the heat of compression and latent heat of evaporation are removed from the vapour by means of cooling air blown over the condensor coil. This cooling causes the vapour to condense with the latent heat thus liberated being carried away by the air stream. The resulting high pressure liquid now flows to the expansion valve or capillary where its pressure is reduced and then into the evaporator coil. The liquid in evaporator coil being in the region of reduced pressure boils vigorously, the necessary sensible heat being absorbed from the enclosed space to cool the air. The cycle is then repeated to provide a continuous cooling effect.
To increase the usefulness of such systems a reversing valve (sometimes known as a four-way valve) is inserted in order that the operation of the condensor and evaporator coils may be reversed. In this way in one position the evaporator coil will operate as normal for cooling and in the other position will act as a condensor coil for heating. The disadvantage of such systems is that there is no controlled rate of dehumidification i.e. water vapour removal from the air of the enclosed space. Without such control the temperature of the enclosed space (during cooling) will be progressively lowered in temperature without some form of external heat being applied to the enclosed space.
The insertion of an external heat supply, e.g., electric heating element, after the evaporator coil may overcome this problem. The disadvantages of such a system are firstly, the rate of energy supplied to the external heat supply must be accurately monitored. Secondly, the cost of providing this external heat is relatively expensive when compared with the cost and efficiency of the air-conditioning system. Thirdly, all the external heat energy supplied is not recycled as it is exhausted to the condensor coil. Fourthly, the set up is very complicated from a logistics viewpoint and the control circuitry required to accurately monitor the temperature and humidity is complicated.
To reduce the energy requirements, it has been proposed to insert an additional evaporator coil in parallel with the evaporator coil. An example of this type of air-conditioning system is disclosed in U.S. Pat. No. 3,779,031. This prior art system will only operate as proposed under a limited range of ambient temperatures. During de-humidification the ambient temperature must be higher than the indoor temperature to avoid a lowering of the indoor temperature. A further disadvantage is that in the cooling cycle both indoor coils are in operation. Accordingly a limited range of cooling can only be achieved.
It is an object of the present invention to provide an air-conditioning system which can control temperature and relative humidity without requiring an external heat source.
A further object of the present invention is to provide an air-conditioning system which can control the temperature and relative humidity over a fairly wide range of values.
With these objects in view, the present invention in one aspect provides an air-conditioning system including a compressor, a first heat exchanger (outdoor), a second heat exchanger (indoor), a third heat exchanger (indoor), a four-way valve the inlet of which communicates with said compressor and the three outlets thereof communicating with one end of a respective one of said heat exchangers, each heat exchanger having a respective expansion valve and electromagnetic shut-off valve in line at the other end of the respective heat exchanger, a pipi
REFERENCES:
patent: 2098443 (1937-11-01), Vancott
patent: 2932178 (1960-04-01), Armstrong et al.
patent: 3188829 (1965-06-01), Siewert et al.
patent: 3293874 (1966-12-01), Gerteis
patent: 3365902 (1968-01-01), Nussbaum
patent: 3460353 (1969-08-01), Ogata et al.
patent: 3779031 (1973-12-01), Akiyama et al.
patent: 4065938 (1978-01-01), Jonsson
patent: 4173865 (1979-11-01), Sawyer
patent: 4311020 (1982-01-01), Tobin et al.
patent: 4482008 (1984-11-01), Nom
patent: 4506521 (1985-03-01), Asano et al.
patent: 4516408 (1985-05-01), Chiba
LandOfFree
Air-conditioning system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Air-conditioning system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Air-conditioning system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1882643