Abstract: An automatic dual pump assembly for a pumped refrigerant cooling system including a refrigerant reservoir for receiving a refrigerant fluid includes a first pump having a first pump inlet and a first pump outlet, a first variable frequency drive coupled to the first pump, a second pump having a second pump inlet and a second pump outlet, a second variable frequency drive coupled to the second pump, and a three-way valve having an input arm fluidly coupled to the refrigerant reservoir, a first outlet arm fluidly coupled to the first pump inlet, and a second outlet arm coupled to the second pump inlet. The first pump outlet and the second pump outlet are coupled to a refrigerant supply line, and the three-way valve selectively controls flow of the refrigerant fluid to one or both of the first pump and the second pump.

Abstract: An economizer module for increasing energy efficiency of a pumped refrigerant cooling system is connected to a refrigerant pumping unit including a primary pump connected with heat extractor(s) via a primary circuit and a primary heat exchanger connected with a condensing unit via a secondary circuit. The economizer module includes a control panel with control software, a secondary heat exchanger connected with the heat extractor(s) via the primary circuit and with the primary heat exchanger, a cooler connected with the secondary heat exchanger via an economizer circuit, and a secondary pump connected between the cooler and the secondary heat exchanger. The control panel executes the control software to control fluid flow in the economizer circuit via the secondary pump so as to use ambient air to reject heat from working fluid being used to collect heat from refrigerant in said primary circuit before said heat travels to said secondary circuit.

Abstract: A lift mechanism a power wheelchair includes linear actuators on opposing sides of the chair that provide a space into which a tilt mechanism can nest when the lift mechanism is in its retracted position. The linear actuators perform both the function of operating the lift mechanism and structurally supporting at least a part of the lift mechanism. The lift mechanism and tilt mechanism are each self-contained modules that can be optionally installed into the power wheelchair.

Abstract: A lift mechanism a power wheelchair includes linear actuators on opposing sides of the chair that provide a space into which a tilt mechanism can nest when the lift mechanism is in its retracted position. The linear actuators perform both the function of operating the lift mechanism and structurally supporting at least a part of the lift mechanism. The lift mechanism and tilt mechanism are each self-contained modules that can be optionally installed into the power wheelchair.