Carrier Corporation

Sivakumar Gopalnarayanan

Timothy P Galante

Pengju Kang

Dong Luo

Tobias H Sienel

Don Alan Schuster

Julio I Concha

Lili Zhang

Robert J Braun

Craig Kersten

Alan Matthew Finn

Yu Chen

Larry D Burns

Robert H Dold

Russell George Lewis

Young Kyu Park

Sathish R Das

Paul M Haydock

Jeffrey T Benoit

Lee A Hoffman

William A Rioux

J Michael Griffin

Heng-Yi Lai

Jeff J Neiter

A method and apparatus for determining the sufficiency of refrigerant charge in an air conditioning system by the use of only two temperature measurements. The temperature of the liquid refrigerant leaving the condenser coil is sensed and the temperature of the condenser coil itself is sensed and the difference between these two measurements is calculated to provide an indication of the adequacy of refrigerant charge in the system. This process is refined by steps taken to eliminate measurements during transient operations and by filtering signals to eliminate undesirable noise. A permitted threshold of deviation is calculated by using probability theory.

Refrigerant charge adequacy gauge

A method and apparatus for determining the sufficiency of the refrigerant charge in an air conditioning system by use of temperature measurements. The temperature of the liquid refrigerant leaving the condenser coil and the outdoor temperature are sensed and representative electrical signals are generated. The electrical signals are converted to digital values that are than compared to predetermined optimal values to determine whether the system is properly charged with refrigerant. An appropriate LED is lighted to indicate that the system is undercharged, overcharged or properly charged. For non-TXV/EXV systems a third parameter i.e. the return air wet bulb temperature is also sensed and a representative digital value thereof is included in the comparison with the predetermined known values to determine if the charge is proper.

Refrigerant charge status indication method and device

The sufficiency of refrigerant charge in an air conditioning system is determined by a comparison of two sensed temperatures in the system, one being the liquid line temperature and the other being either the outdoor temperature or the condenser coil temperature. In one embodiment the two sensed temperatures are displayed on respective thermochromic strips which are so calibrated and juxtaposed as to provide a visual indication, by the relative positions of the two displayed sensed temperatures, as to whether the refrigerant charge is adequate. In another embodiment, the sensed liquid line temperature is displayed by way of a plurality of LEDs and the other temperature is displayed by way of a marker on a temperature scale. If the two displayed temperatures are aligned, then the refrigerant charge is optimized, and if they are not aligned, the system is undercharged or overcharged.

Dual thermochromic liquid crystal temperature sensing for refrigerant charge indication

An air conditioning system includes a plurality of sensors for sensing temperature and/or pressure conditions of the system which collectively indicate the actual refrigerant charge level in the system. This level is then compared with optimum level values that are stored in memory, and the difference between the two is used to indicate whether the system is properly charged. If not, the difference is applied to open a charge valve or a purge valve to automatically install additional refrigerant or to remove refrigerant so as to establish an optimum volume of refrigerant in the system.

Automatic refrigerant charging apparatus

A braze-free connector suitable for use in a refrigeration system that includes a connector body having a circular opening passing therethrough. The opening has a converging section that tapers downwardly from the entrance to the opening toward the back of the opening. A ferrule is slidably mounted upon a refrigerant tube which is inserted into the opening to place a tapered collapsible section of the ferrule in contact with the tapered section of the opening. The non-collapsible section of the ferrule is keyed to a nut which in turn is mated with a male thread formed on the connector body whereby the collapsible section of the ferrule is forced into engagement with the refrigerant tube. A pressure sensitive sealant is pre-coated upon at least the collapsible section of the ferrule which is activated as the ferrule is forced into engagement with the refrigerant tube.

Braze-free connector utilizing a sealant coated ferrule

The refrigerant charge adequacy of an air conditioning system is determined by the sensing of two temperatures in the system, one being at a midpoint in a condenser coil and the other being the temperature in the liquid line of the condenser discharge, with the difference then being indicative of the degree of subcooling, which, in turn, may be indicative of refrigerant charge condition. The method is refined by measuring a third temperature at the compressor discharge, with the three temperature values then being used to calculate a pair of residual values which provide an indication of whether the two temperature approach is useful in determining charge adequacy under the existing conditions and if not, whether the system is overcharged or undercharged.

Detection of refrigerant charge adequacy based on multiple temperature measurements

In a residential furnace having a layered insulation material on the inner walls of the heat exchanger compartment, the inner aluminum foil layer has a plurality of holes formed therein in order to allow for the outer layer to absorb the sound within the heat exchanger compartment and thereby reduce the noise emanating from the furnace. Both the density and size of the holes are optimized to maximize the sound absorption performance over the particular frequency ranges that are characteristic of the furnace.

Use of thermal insulation for noise abatement

A transcritical refrigeration system includes a compressor, a gas cooler, an expansion device, and an evaporator. Refrigerant is circulated though the closed circuit system. Preferably, carbon dioxide is used as the refrigerant. A fan moves outdoor air that exchanges heat with the refrigerant across the evaporator. The speed of the fan is regulated to regulate the evaporator pressure and to adapt the evaporator to different environmental conditions to achieve the optimal coefficient of performance. During high ambient conditions, the fan speed is decreased, decreasing the refrigerant mass flowrate in the system. The energy exchange per unit mass of the refrigerant in the gas cooler increases and the work of the fan decreases, increasing the coefficient of performance of the system. During low ambient conditions, the mass flowrate of the system is low and there is more heat transfer thermal resistance on the refrigerant side at the evaporator. The speed of the fan is lowered to decrease the work of the fan. Therefore, the coefficient of performance increases.

Refrigeration system having variable speed fan

The efficiency of a vapor compression system is increased by coupling the evaporator with either the intercooler of a two-stage vapor compression system or the compressor component. The refrigerant in the evaporator accepts heat from the compressor component or the refrigerant in the intercooler, heating the evaporator refrigerant. As pressure is directly related temperature, the low side pressure of the system increases, decreasing compressor work and increasing system efficiency. Additionally, as the heat from the compressor component or from the refrigerant in the intercooler is rejected to the refrigerant in the evaporator, the compressor is cooled, increasing the density and the mass flow rate of the refrigerant to further increase system efficiency.

Method for increasing efficiency of a vapor compression system by evaporator heating

The expansion of a high pressure or intermediate pressure refrigerant in an expansion device in a transcritical vapor compression system converts the potential energy into usable kinetic energy. The kinetic energy provides work which is employed to fully or partially drive an expansion motor unit which is coupled to rotating auxiliary machinery. By providing work to the rotating auxiliary machinery, system efficiency is improved. The auxiliary rotating machinery can be an evaporator fan or a gas cooler fan to pull the refrigerant through the evaporator and gas cooler, respectively. Alternatively, the auxiliary rotating machinery can be a water pump or an oil pump.

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Simsbury, CT, United States of America

Sivakumar Gopalnarayanan