Abstract: A closed cycle heat transfer device comprising a boiler (10) and a condenser (13), the condenser being used to recover useful heat by latent heat evaporation. A circuit defined by the boiler (10), condenser (13) and ducts (12, 15) is to be liquid-filled at a pressure just above atmospheric pressure. An expansion device (16) maintains the working pressure in the circuit but will receive excess condensate in a liquid phase to compensate for expansion of the working fluid vapor which passes from the boiler (10) to the condenser (13). The expansion chamber contains a movable or flexible member which, when working liquid is received in the chamber, is displaced to compress a gas in the chamber.

Abstract: A system for generating back-up electrical power. The system includes a vessel adapted to contain a volume of compressed gas and a valve to release gas from the vessel at a predetermined pressure. A scroll expander is adapted to receive and pass the released gas. A rotary member is rotated by the flow of the released gas passed by the expander. An electrical generator is drivingly connected to the rotatable member of the expander to generate a supply of electrical power. A power conditioning unit has at least one capacitor to store electrical energy to provide a back-up electrical supply for a brief period until the scroll expander and generator can produce the required supply of electrical power.

Abstract: A closed cycle heat transfer device comprising a boiler (10) and a condenser (13), the condenser being used to recover useful heat by latent heat evaporation. A circuit defined by the boiler (10), condenser (13) and ducts (12, 15) is to be liquid-filled at a pressure just above atmospheric pressure. An expansion device (16) maintains the working pressure in the circuit but will receive excess condensate in a liquid phase to compensate for expansion of the working fluid vapour which passes from the boiler (10) to the condenser (13). The expansion chamber contains a movable or flexible member which, when working liquid is received in the chamber, is displaced to compress a gas in the chamber.

Abstract: A linear or rotary positive displacement expander (10) is fed by compressed gas or vapour from a reservoir (11) by means of a fast acting pulsed flow control valve (12) actuated by a PWM microprocessor (13) which receives input data from the expander (10) and the reservoir (11) to determine the correct operation of the valve (12). By injecting single or multiple controlled volume pulses of gas into the expander (10), the need for additional pressure regulation between the reservoir (11) and the expander (10) is eliminated, and the expander can operate efficiently within its built-in pressure ratio capability whereby the gas or vapour is expanded to be as close as possible to ambient pressure at the outlet of the expander.

Abstract: A system for generating back-up electrical power. The system includes a vessel adapted to contain a volume of compressed gas and a valve to release gas from the vessel at a predetermined pressure. A scroll expander is adapted to receive and pass the released gas. A rotary member is rotated by the flow of the released gas passed by the expander. An electrical generator is drivingly connected to the rotatable member of the expander to generate a supply of electrical power. A power conditioning unit has at least one capacitor to store electrical energy to provide a back-up electrical supply for a brief period until the scroll expander and generator can produce the required supply of electrical power.