A multi-stage gas compression system useful at the production site and at central collection points, having an energy efficient and effective intercooler system. The system includes a reciprocating compressor having a plurality of compressor valves and cylinders configured in series to provide staged compression to the natural gas. Coupled with the compressor are an inlet port for receiving natural gas to be compressed, and an outlet port for delivering compressed fluid from the compressor to a discharge line, to the transmission pipeline or storage. Facilitating transmission and intercooling of the natural gas between cylinders are a plurality of pipes, each pipe in close proximity with an intercooler. The rate of cooling of the intercooler is determined by a control system coupled therewith, including a temperature sensor positioned within pipe proximal to the intercooler, and means to compare the temperature measured by the temperature sensor and an optimal temperature or temperature range, and determine appropriate levels of cooling provided by the intercooler.

A refrigeration apparatus includes a gas-liquid separator on a downstream side of a radiator, and a refrigerant circuit in which a high pressure of a refrigeration cycle is equal to or higher than a critical pressure. The refrigeration apparatus includes a gas passage that communicates with the gas-liquid separator and at least one of a plurality of heat exchangers provided in the refrigerant circuit, and an opening and closing device that opens and closes the gas passage. There is provided a controller that opens the opening and closing device when a pressure in the gas-liquid separator is equal to or higher than a predetermined value in a state where a compression unit of the refrigerant circuit is stopped to suppress occurrence of pressure abnormality inside the gas-liquid separator in a state where a compressor is stopped.

Disclosed herein a cooling system includes a refrigerant circulator that a refrigerant is circulated, wherein the refrigerant circulator includes a first compressor configured to pressurize the refrigerant in gaseous state; a first cooler configured to cool the refrigerant pressurized by the first compressor; a first gas-liquid separator configured to separate the refrigerant cooled by the first cooler into a first refrigerant flow of a gas component and a second refrigerant flow of a liquid component; a second compressor configured to pressurize the first refrigerant flow; a second cooler configured to cool the first refrigerant flow pressurized by the second compressor; a second gas-liquid separator configured to separate the refrigerant cooled by the second cooler into a third refrigerant flow of a gas component and a fourth refrigerant flow of a liquid component; a first expansion member configured to decompress the fourth refrigerant flow.

A system for separating a soluble solution includes a first freezer configured to receive a liquid feed stream and a refrigerant stream, and discharge a concentrated solution stream, wherein the first freezer is configured to exchange heat between the liquid feed stream and the refrigerant stream through direct contact within the first freezer and freeze a portion of the liquid feed stream, a first separator external to the first freezer and configured to separate ice particles from the concentrated solution stream and recirculate the concentrated solution stream to the first freezer, and a first ice washer coupled to the first separator and configured to receive the ice particles separated from the concentrated solution stream by the first separator and wash the separated ice particles to free the ice particles from contaminants.

A climate-control system includes a first compressor, a second compressor, a first heat exchanger, a second heat exchanger, and a third heat exchanger. The first compressor includes a first inlet and a first outlet. The second compressor is in fluid communication with the first compressor and includes a second inlet (e.g., a suction inlet), a third inlet (e.g., a vapor-injection inlet), a second compression mechanism, and a second outlet. The second and third inlets are fluidly coupled with the second compression mechanism. The second compression mechanism receives working fluid from the first compressor through the third inlet and discharges working fluid through the second outlet of the second compressor. The first and second compressors are in fluid communication with the first, second, and third heat exchangers.

A heat source unit constitutes a refrigeration apparatus by being connected to a utilization-side unit. The heat source unit includes a low-stage compression element, a high-stage compression element, and a heat exchanger. The low-stage compression element has a discharge pipe provided with a pressure switchgear. The high-stage compression element compresses a refrigerant discharged from the low-stage compression element. When the low-stage compression element is paused in response to activation of the pressure switchgear, the high-stage compression element operates while the low-stage compression element is kept paused.

Provided is a refrigeration apparatus capable of appropriately supplying oil separated by oil separators to compressors according to the situation. The refrigeration apparatus includes N refrigeration units each including a compressor, an oil separator, an oil return pipe, and a heat dissipation heat exchanger; N pressure reducing valves each connected to the heat dissipation heat exchanger of a corresponding one of the N refrigeration units; and an oil return control mechanism that controls a return destination of the oil separated by the oil separators of the N refrigeration units. The oil return control mechanism includes an oil supply pipe that connects the oil return pipes of the N refrigeration units to each other, and a flow control mechanism, which controls a flowing condition of oil in the oil supply pipe, disposed in the oil supply pipe.

Provided is a refrigeration apparatus capable of appropriately supplying oil separated by oil separators to compressors according to the situation. The refrigeration apparatus includes refrigeration units each including a compressor, an oil separator, an oil return pipe, and a heat dissipation heat exchanger; a pressure reducing valve connected to the heat dissipation heat exchangers; and an oil return control mechanism controlling a return destination of the oil separated by the oil separators. The oil return control mechanism includes an oil supply pipe connecting the oil return pipes; a flow control mechanism, controlling a flowing condition of oil in the oil supply pipe, disposed in the oil supply pipe; and an ejection control mechanism, controlling an ejection condition of oil ejected from the oil separator, disposed in each oil return pipe at a position closer to the oil separator than a connection position with the oil supply pipe is.

A refrigerant circuit of a refrigeration apparatus performs a refrigeration cycle in which a high pressure is equal to or greater than the critical pressure of a refrigerant. The refrigeration apparatus performs at least a heat application operation in which an indoor heat exchanger of the refrigerant circuit functions as a radiator. A controller of the refrigeration apparatus controls the opening degree of the indoor expansion valve of the refrigerant circuit so that the temperature of the refrigerant at the outlet of the indoor heat exchanger reaches a predetermined reference temperature, in the heat application operation.

A valve mechanism (14a, 14b, 63a, 63b, 90) includes: a valve body (80, 95); a first flow path (81) located opposite a distal end (80a, 95b) of the valve body (80, 95); a driver (85) configured to move the valve body (80, 95) to a first position where the distal end (80a, 95b) of the valve body (80, 95) closes the first flow path (81) and a second position where the distal end (80a, 95b) of the valve body (80) opens the first flow path (81); and a second flow path (82) configured to communicate with the first flow path (81) when the valve body (80) is at the second position. The high-pressure flow path (I1, I2, O2, O3, 48) causes the high-pressure refrigerant to always flow through the second flow path (82) and first flow path (81) of the valve mechanism (14a, 14b, 63a, 63b, 90) in this order.