Abstract: A closed loop refrigerant expansion system with a tube and shell condenser is provided with a control which, upon shutdown, causes the flow of refrigerant to reverse from the evaporator to the condenser to thereby both reduce the amount of refrigerant vapor passing to the condenser and increase the amount of liquid refrigerant in the condenser to thereby reduce the maximum temperature load in the condenser. Reverse flow can be made to occur either by reversing the direction of the refrigerant pump or opening a bypass valve around the pump.

Abstract: A vapor expansion/compression system having an oil sump for lubrication of the turbine/compressor bearings includes an oil and/or vapor vent line leading from a strategic location in the oil sump to the condenser such that the oil level in the sump is limited to the predetermined level, and any excess oil is pumped from the sump to thereby prevent the oil level from reaching a level at which bearings failure could be caused due to a high oil level.

Abstract: An organic rankine cycle system includes a sensor for sensing a condition indicative of pressure within the system and a control which responsively provides heat to said system when the pressure within the system is sensed to be at a predetermined threshold, near ambient pressure, during periods in which the system is shut down or preparing to operate. Provision is also made to remove the heat from the system when the pressure therein rises to a predetermined higher pressure threshold.

Abstract: A power generating system in one embodiment employs a Rankine Cycle system that is coupled to multiple heat sources. The Rankine cycle system includes a customized working fluid that comprises a mixture of a plurality of constituent fluids, the selection of which causes the mixture to exhibit a working fluid profile. In one embodiment, the working fluid profile includes a temperature glide portion selected and optimized based on operating conditions of the heat sources, wherein the temperature glide portion includes a constituent phase point at which one of the constituent fluids undergoes a phase change before the other constituent fluids of the mixture.

Abstract: A pair of organic rankine cycle systems are connected in series with the geothermal fluid passing first through an evaporator of the first system and then through an evaporator of the second system before returning to a sink. Similarly, the cooling tower is arranged to provide cooling water to pass first through the condenser in one system and then through the condenser of the other system, to reduce the total flow required and the size of associated cooling hardware.

Abstract: A vapor expansion/compression system having an oil sump for lubrication of the turbine/compressor bearings includes an oil and/or vapor vent line leading from a strategic location in the oil sump to the condenser such that the oil level in the sump is limited to the predetermined level, and any excess oil is pumped from the sump to thereby prevent the oil level from reaching a level at which bearings failure could be caused due to a high oil level.

Abstract: A closed loop refrigerant expansion system with a tube and shell condenser is provided with a control which, upon shutdown, causes the flow of refrigerant to reverse from the evaporator to the condenser to thereby both reduce the amount of refrigerant vapor passing to the condenser and increase the amount of liquid refrigerant in the condenser to thereby reduce the maximum temperature load in the condenser. Reverse flow can be made to occur either by reversing the direction of the refrigerant pump or opening a bypass valve around the pump.

Abstract: An organic rankine cycle system includes a sensor for sensing a condition indicative of pressure within the system and a control which responsively provides heat to said system when the pressure within the system is sensed to be at a predetermined threshold, near ambient pressure, during periods in which the system is shut down or preparing to operate. Provision is also made to remove the heat from the system when the pressure therein rises to a predetermined higher pressure threshold.