Method for controlling a hydronic system

Abstract

A method for controlling a hydronic system having a thermal source and at least a first and a second load circuit connected to the thermal source via a hydraulic system. The system having a changeover valve being configured to selectively activate a flow of heat transfer medium through the first or the second load circuit. Wherein for distributing the required thermal energy to the load circuits in at least one operational condition a duty cycle for the first load circuit is extended, resulting in a shortening of the duty cycle of the second load circuit, and for compensating this shortening of the duty cycle the temperature and/or flow of the heat transfer medium supplied to the second load circuit are adjusted, as well as a hydraulic unit for a hydronic system.

1 . A method for controlling a hydronic system comprising a thermal source and at least a first and a second load circuit connected to the thermal source via a hydraulic system having a changeover valve, said changeover valve being configured to selectively activate a flow of heat transfer medium through the first or the second load circuit, the method comprising the steps of:
 for distributing the required thermal energy to the load circuits in at least one operational condition, extending a duty cycle for the first load circuit, resulting in a shortening of the duty cycle of the second load circuit, and   for compensating this shortening of the duty cycle, adjusting a temperature and/or flow of the heat transfer medium supplied to the second load circuit.   
     
     
         2 . The method according to  claim 1 , wherein the duty cycle, temperature and/or flow of the heat transfer medium are set on a basis of the energy demand of the respective load circuit. 
     
     
         3 . The method according to  claim 1 , wherein the energy demand of at least one of the load circuits is detected on a basis of a temperature difference between supply and return temperature detected in the load circuit and the flow inside the respective load circuit. 
     
     
         4 . The method according to  claim 1 , wherein pressure and/or flow of the heat transfer medium in the first load circuit are set to avoid noise occurring in the first load circuit. 
     
     
         5 . The method according to  claim 1 , wherein the temperature and/or flow of the heat transfer medium supplied to the second load circuit are adjusted if the energy demand cannot be satisfied at a maximum duty cycle for the second load circuit. 
     
     
         6 . The method according to  claim 5 , wherein the maximum duty cycle for the second load circuit is defined by a minimum duty cycle for the first load circuit. 
     
     
         7 . The method according to  claim 1 , wherein the temperature of the heat transfer medium is adjusted by a mixing device or mixing valve which mixes a supply flow from the thermal source with a return flow in an adjustable mixing ratio. 
     
     
         8 . The method according to  claim 1 , wherein the flow of heat transfer medium is adjusted by controlling the speed of a circulator pump in the hydraulic system. 
     
     
         9 . The method according to  claim 1 , wherein the changeover valve, the flow of the heat transfer medium and/or the temperature of the heat transfer medium are controlled by a central control device. 
     
     
         10 . A hydraulic unit for a hydronic system, the hydraulic unit comprising:
 a thermal source inlet;   a thermal source outlet;   at least one first load circuit connection;   at least one second load circuit connection;   a changeover valve connected to the first load circuit connection and to the second load circuit connection and configured to selectively activate a flow of heat transfer medium through the first or the second load circuit; and   a control device controlling said changeover valve, wherein said control device is configured such that for distributing the required thermal energy to the load circuits by control of the changeover valve in at least one operational condition a duty cycle for the first load circuit is extended, resulting in a shortening of the duty cycle of the second load circuit, and that for compensating this shortening of the duty cycle the temperature and/or flow of the heat transfer medium supplied to the second load circuit are adjusted.   
     
     
         11 . The hydraulic unit according to  claim 10 , further comprising a mixing device, which is configured to adjust the temperature of a heat transfer medium by admixing a return flow, wherein said mixing device is controlled by said control device. 
     
     
         12 . The hydraulic unit according to  claim 10 , wherein said mixing device comprises a mixing valve driven by an electric, magnetic, or thermoelectric actor. 
     
     
         13 . The hydraulic unit according to  claim 1 , wherein a circulator pump producing a flow of heat transfer medium, wherein said circulator pump is controlled by said control device. 
     
     
         14 . The hydraulic unit according to  claim 10 , wherein said control device is arranged within a motor housing of the circulator pump and/or within an electronics housing attached to the motor housing of the circulator pump. 
     
     
         15 . The hydraulic unit according to  claim 10 , wherein said changeover valve comprises a valve element movable by a flow and/or pressure of the heat transfer medium, the flow and pressure are produced by a circulator pump, and that said circulator pump is controlled by said control device such that the flow and/or pressure are adjusted by the control device to change the position of the valve element. 
     
     
         16 . The method according to  claim 4 , wherein the flow is limited to a maximum flow. 
     
     
         17 . The method according to  claim 9 , wherein the control device is integrated into a circulator pump unit.