Abstract: A passive ventilation stack for a room, building or the like comprises an interior space and first and second openings providing fluid communication between the interior space and a room to be ventilated, and the outside atmosphere. A control system is provided for varying the size of the openings, so as to cause natural heat exchange between relatively cool ventilation air entering the stack from outside and relatively warm air entering the stack from a room or building to be ventilated.

Abstract: There is provided a computer-implemented method for estimating flow of fluid into a production well extending into a reservoir comprising fluid, the well comprising a central tubing and an annulus surrounding the central tubing. The annulus is connected to the reservoir so as to receive fluid at one or more inflow locations. The central tubing has at least one inlet, arranged to allow fluid to flow from the annulus into the central tubing, and is located downstream of the one or more inflow locations. The production well further comprises one or more devices arranged to measure a temperature of fluid within the annulus at a plurality of points along the length of the annulus.

Abstract: A passive ventilation stack for a room, building or the like comprises an interior space and first and second openings providing fluid communication between the interior space and a room to be ventilated, and the outside atmosphere. A control system is provided for varying the size of the openings, so as to cause natural heat exchange between relatively cool ventilation air entering the stack from outside and relatively warm air entering the stack from a room or building to be ventilated.