The present invention relates to a method of operating an electric motor-driven centrifugal pump (3) in a hydraulic system (4) having at least one self-controlled load, where a gradient (dQ.sub.akt/dt) of the volumetric flow rate (Q.sub.akt) of the centrifugal pump (3) is determined and the current set-point delivery head (H.sub.soll) of the centrifugal pump (3) is calculated from a mathematical operation on the gradient (dQ.sub.akt/dt) weighted with a gain factor (K) and the last specified set-point delivery head (H.sub.soll,alt). The operation describes a positive feedback between the set-point delivery head (H.sub.soll) and the volumetric flow rate (Q.sub.akt). The gain factor (K) is determined from a calculation instruction that is modified dynamically during operation of the centrifugal pump (3) taking into consideration the current operating point of the centrifugal pump (3) and taking into consideration a current and/or at least one past state of the hydraulic system (4).

A hydronic distribution system includes self-regulating valves networked together and operable to share valve temperature and valve position information with a microprocessor or other type of controller. The microprocessor runs one or more algorithms that process the temperatures and positions of the valves and then computes a desired speed for one or more variable speed pumps within the system. Controlling the pumps to operate at the desired speed and still maintain the correct amount of process fluid flow needed by the system reduces the overall energy use of the hydronic distribution system, saves on the operational lives of the pumps, and increases system efficiency.

A hydronic distribution system obtains, in real time, valve operating information from one or more valves arranged in a network, executes a speed determination algorithm which processes the valve operating information to determine a desired speed for one or more pumps to maintain a desired amount of process fluid flow of a process fluid to plural coils, and sets a speed of the one or more pumps, based on the desired speed for the one or more pumps that is determined.

The present invention is a fluid distribution system comprising connected conduits (e.g., lines) wherein fluid flows, such as pipes within a building. The lines may be configured to: (i) include multiple lines that connect at intersections (some of the intersections will be identified as nodes); and (ii) incorporate node units associated with pressure assemblies (“PSAs”). Activities of a node unit incorporating a PSA can result in alterations in fluid flow, such as by a loop control process or other processes to operate one or more pumps. Each PSA has a pump incorporated therein. These alterations adjust fluid flow to cause the system to produce a balanced and high efficiency energy transfer (e.g., heating or cooling), and do not require any: addition of any line (conduit) pressure losses, measuring of differential pressure, or identification or use of any specific, fixed or absolute pressure value. Each PSA functions based on an operation locus (for a node unit) and/or an operation locus range (for node unit groupings) to adjust the fluid flow.

A method of balancing a heating system with a flow system, including a supply flow line (60) and a return flow line (70), a heat source (55) and a pump (10) hydraulic lines (L.sub.1-L.sub.n), some having a heating element (H.sub.1-H.sub.n) with a balancing valve (V.sub.1-V.sub.n). The method includes: carrying out one or more measurements by opening one hydraulic line only and determining a flow rate through the pump and a pressure difference across the pump, establishing a hydraulic model based on the determined flow rate and pressure difference from at least two measurements from step, and at least one additional measurement for at least two hydraulic lines, specifying a desired flow rate for each of the hydraulic lines, and adjusting one or more of the dedicated balancing valves in order to meet the desired flow rate for each of the hydraulic lines by using the hydraulic model.

An air-conditioning apparatus includes: a heat-source-side device that heats or cools a heat medium; a pump that sucks and transfers the heat medium; use-side heat exchangers; a heat medium circuit; flow rate control devices; indoor-side pressure sensors; a pump inlet-side pressure sensor and/or a pump outlet-side pressure sensor; a flow rate detection device that detects a pump flow rate; and a controller that performs a first operation in which the flow rate control devices are individually opened or closed and data regarding a flow passage resistance at a path related to each of the heat exchangers is obtained, and a second operation in which heat is supplied to indoor air, and calculates calculate flow rates of the heat medium that flows through the heat exchangers in the second operation, from pump flow rates and pressures detected by the pressure sensors in the first and second operations.

A method to control a carrier fluid through a service line (5) of a conditioning and/or heating system (1). The service line includes a heat exchange unit (7), a flow regulator (8), temperature sensors (9; 9a, 9b) detecting a temperature difference (ΔT.sub.i) between the carrier fluid in a first section (5a) of the service line (5) upstream of said heat exchange unit (7) and carrier fluid in a second section (5b) of the service line (5) downstream of the same heat exchange unit (7). The method includes calculating a value assumed by a control parameter (Pc) which is a function of at least one or more values assumed by the temperature difference in the transition of the flow regulator from a first to a second operating condition, for then determining whether the value of the control parameter (Pc) is higher than a threshold (S).

A hot water energy storage system (100) comprises a storage vessel (102); a pump (151); a heat exchanger (152) arranged to receive water from the storage vessel (102) and to output water to the storage vessel (102); a diverting valve (158) to divert a proportion of the water output from the heat exchanger (152) back to an inlet of the heat exchanger (152), bypassing the storage vessel (102); a temperature sensor (120a-c) to measure a temperature of water within the system (100); and a control system (130). The control system (130) controls the pump (151) and the diverting valve (158), based on a temperature measurement of the water and the desired quantity of heat to be transferred by the heat exchanger (152), so as to maintain the return temperature of water entering the storage vessel (102) within a specified range whilst transferring the desired quantity of heat.

A hydronic distribution system includes self-regulating valves networked together and operable to share valve temperature and valve position information with a microprocessor or other type of controller. The microprocessor runs one or more algorithms that process the temperatures and positions of the valves and then computes a desired speed for one or more variable speed pumps within the system. Controlling the pumps to operate at the desired speed and still maintain the correct amount of process fluid flow needed by the system reduces the overall energy use of the hydronic distribution system, saves on the operational lives of the pumps, and increases system efficiency.

A hydraulic manifold for hydraulic heating and/or cooling systems includes a feed conduit and a return conduit. The feed conduit includes at least one feed connection and the return conduit includes at least one return connection, for the connection of a load circuit. The manifold has a modular construction with a main module and connected load module(s). The main module includes a section of the feed conduit and/or of the return conduit as well as an electric connection. The load module includes a section of the feed conduit with a feed connection, and/or a section of the return conduit with a return connection, as well as at least one regulating device for regulating the flow through a load circuit connected to the feed connection and to the return connection. The main module includes a manifold control device for the control of the regulating device in the load module(s).