Abstract: The present invention relates to a binary assay method capable of providing wide dynamic range and a high degree of precision in which analyte and labelled ligand are reacted with two independently determinable forms of solid-supported binding partners having affinity for the analyte and labelled ligand, respectively. The analyte concentration is determined from signals deriving from the resulting two forms by reference to a double standard calibration curve. A kit for use in the method is also disclosed.

Abstract: High side pressure in a transcritical vapor compression cycle system is regulated by varying a liquid inventory of a low pressure refrigerant receiver provided in a circuit of the system. The circuit includes a compressor, a gas cooler, a throttling valve, an evaporator and the receiver connected in series in a closed circuit operating at supercritical pressure in a high pressure side of the circuit. The degree of opening of the throttling valve is controlled to regulate the high side pressure in the circuit. It is possible to control capacity, and it also is possible to achieve minimum energy consumption for a given capacity requirement by regulating high side pressure.