Abstract: A method for operating a closed circuit vapour compression refrigeration system is disclosed. The system may operate with supercritical pressure on a high pressure side, and includes at least one compressor, at least one heat rejector, at least two in parallel connected heat absorbers, at least one variable expansion means up flow of each heat absorber and at least one control unit for controlling the variable expansion means, connected to a set of sensors. The flow rate of the refrigerant through each of the variable expansion means, is controlled by the control unit, coordinating the flow of refrigerant through each of the variable expansion means to maintain a control parameter within a set range. Any surplus charge resulting from the control is buffered on a low pressure side of the system. Furthermore a refrigeration system based on a closed vapour compression circuit is described.

Abstract: A method for operating a closed circuit vapour compression refrigeration system is disclosed. The system may operate with supercritical pressure on a high pressure side, and includes at least one compressor, at least one heat rejector, at least two in parallel connected heat absorbers, at least one variable expansion means up flow of each heat absorber and at least one control unit for controlling the variable expansion means, connected to a set of sensors. The flow rate of the refrigerant through each of the variable expansion means, is controlled by the control unit, coordinating the flow of refrigerant through each of the variable expansion means to maintain a control parameter within a set range. Any surplus charge resulting from the control is buffered on a low pressure side of the system. Furthermore a refrigeration system based on a closed vapour compression circuit is described.

Abstract: The present invention involves a compression refrigeration system including a compressor, a heat rejector, expansion means and a heat absorber connected in a closed circulation circuit that may operate with supercritical high-side pressure. An apparatus and method are provided to optimize energy efficiency.

Abstract: A compression refrigeration system that includes a compressor, a heat rejector, expansion means and a heat absorber connected in a closed circulation circuit that may operate with supercritical high-side pressure.

Abstract: Reversible vapor compression system including a compressor (1), an interior heat exchanger (2), an expansion device (6) and an exterior heat exchanger (3) connected by means of conduits in an operable relationship to form an integral main circuit. A first device is provided in the main circuit between the compressor and the interior heat exchanger, and a second device is provided on the opposite side of the main circuit between the interior and exterior heat exchangers to enable reversing of the system from cooling mode to heating mode and vice versa. The first and second device for reversing of the system include a first and second sub-circuit (A respectively B) each of which is connected with the main circuit through a flow reversing device (4 and 5 respectively). Included in the system solution is a reversible heat exchanger for refrigerant fluid, particularly carbon dioxide. It includes a number of interconnected sections arranged with air flow sequentially through the sections.

Abstract: A compression refrigeration system includes a compressor (1), a heat rejector (2), expansion device (3) and a heat absorber (4) connected in a closed circulation circuit that may operate with supercritical high-side pressure. The refrigerant charge and component design of the system corresponds to a stand still pressure inside the system which lower than 1.26 times the critical pressure of the refrigerant when the temperature of the whole system is equalized to 60° C. Carbon dioxide or a mixture of a refrigerant containing carbon dioxide may be applied as the refrigerant in the system.

Abstract: A compression refrigeration system includes a compressor (1), a heat rejector (2), expansion means (3) and a heat absorber (4) connected in a closed circulation circuit that may operate with supercritical high-side pressure.

Abstract: A compression refrigeration system includes a compressor (1), a heat rejector (2), expansion means (3) and a heat absorber (4) connected in a closed circulation circuit that may operate with supercritical high-side pressure.

Abstract: A method of defrosting of a heat exchanger (evaporator) in a vapor compression system including, downstream of a heat exchanger (evaporator) (3) to be defrosted, at least a compressor (1), a second heat exchanger (condenser/heat rejecter) (2), and an expansion device (6) connected by conduits in an operable manner to form an integral closed circuit. The heat exchanger (3) to be defrosted is subjected to essentially the same pressure as the compressor's (1) discharge pressure. Thus, the heat exchanger (3) is defrosted as the high-pressure discharge gas from the compressor (1) flows through to the heat exchanger, giving off heat to the heat exchanger (3). In the circuit, in connection with the expansion device (6) a first bypass loop 23 with a first valve (16?), is provided.

Abstract: Reversible vapor compression system including a compressor (1), an interior heat exchanger (2), an expansion device (6) and an exterior heat exchanger (3) connected by means of conduits in an operable relationship to form an integral main circuit. A first means is provided in the main circuit between the compressor and the interior heat exchanger, and a second means is provided on the opposite side of the main circuit between the interior and exterior heat exchangers to enable reversing of the system from cooling mode to heat pump mode and vice versa.

Abstract: A compression refrigeration system includes a compressor (1), a heat rejector (2), expansion means (3) and a heat absorber (4) connected in a closed circulation circuit that may operate with supercritical high-side pressure. The refrigerant charge and component design of the system corresponds to a stand still pressure inside the system which lower than 1.26 times the critical pressure of the refrigerant when the temperature of the whole system is equalised to 60 degrees C. Carbon dioxide or a mixture of a refrigerant containing carbon dioxide may be applied as the refrigerant in the system.

Abstract: Method for defrosting of a heat exchanger (evaporator) in a vapor compression system including, beyond a heat exchanger (evaporator) (3) to be defrosted, at least a compressor (1), a second heat exchanger (condenser/heat rejecter) (2) and an expansion device (6) connected by conduits in an operable manner to form an integral closed circuit. The heat exchanger (3) to be defrosted is subjected to essentially the same pressure as the compressor's (1) discharge pressure whereby the heat exchanger (3) is defrosted as the high-pressure discharge gas from the compressor (1) flows through to the heat exchanger, giving off heat to the said heat exchanger (3).

Abstract: A refrigerating or heat pump system includes an evaporator (23), a compressor (20), an air-cooled heat rejecting heat exchanger (21) and an expansion device (22) being connected in a closed circuit and operating in a trans critical vapor compression cycle. The heat rejecting heat exchanger (21) is cooled by natural upwards circulation/convention of air. In a preferred embodiment the heat rejecting exchanger (21) is built into an air flow conduit or shell (11) to improve the natural air circulation by obtaining a chimney effect.

Abstract: Reversible vapor compression system including a compressor (1), an interior heat exchanger (2), an expansion device (6) and an exterior heat exchanger (3) connected by means of conduits in an operable relationship to form an integral main circuit. A first means is provided in the main circuit between the compressor and the interior heat exchanger, and a second means is provided on the opposite side of the main circuit between the interior and exterior heat exchangers to enable reversing of the system from cooling mode to heating mode and vice versa. The first and second means for reversing of the system include a first and second sub-circuit (A respectively B) each of which is connected with the main circuit through a flow reversing device (4 and 5 respectively) Included in the system solution is a reversible heat exchanger for refrigerant fluid, particularly carbon dioxide. It includes a number of interconnected sections arranged with air flow sequentially through the sections.