District Energy Sharing System

Abstract

A district energy sharing system (DESS) comprises a thermal energy circuit which circulates and stores thermal energy in water, at least one client building thermally coupled to the circuit and which removes some thermal energy from the circuit (“thermal sink”) and/or deposits some thermal energy into the circuit (“thermal source”), and at least one thermal server plant that can be thermally coupled to external thermal sources and/or sinks (e.g. a geothermal ground source) and whose function is to maintain thermal balance within the DESS.

1 . A district energy sharing system comprising:
 a thermal energy circuit comprising:
 a warm liquid conduit for flow of a heat transfer liquid therethough at a first temperature; 
 a cool liquid conduit for flow of the heat transfer liquid therethrough at a second temperature that is lower than the first temperature; and 
   a heat pump assembly comprising
 a reversible heat pump; 
 a building heat exchanger thermally coupled to the heat pump and for thermally coupling to a client building; and 
 a circuit heat exchanger thermally coupling the heat pump to the thermal energy circuit; 
 piping fluidly coupling the circuit heat exchanger to the warm and cool liquid conduits; 
 at least one circulation pump coupled to the piping; and 
 a valve assembly comprising at least one control valve coupled to the piping and switchable between a heating mode wherein a fluid pathway is defined through the piping for flow of the heat transfer liquid from the warm liquid conduit through the circuit heat exchanger and to the cool liquid conduit, and a cooling mode wherein a fluid pathway is defined through the piping for flow of the heat transfer fluid from the cool liquid conduit through the heat exchanger and to the warm liquid conduit. 
   
     
     
         2 . A system as claimed in  claim 1  wherein the valve assembly is further switchable into an off mode wherein the warm and cool liquid conduits are not in fluid communication with the heat exchanger through the piping. 
     
     
         3 . A system as claimed in  claim 1  wherein the at least one control valve is a modulating valve. 
     
     
         4 . A system as claimed in  claim 1  wherein the valve assembly comprises a pair of three-way control valves wherein a first three-way control valve is fluidly coupled to the warm liquid conduit, cool liquid conduit, and an inlet of the circuit heat exchanger, and a second three-way control valve is fluidly coupled to the warm liquid conduit, cool liquid conduit, and an outlet of the circuit heat exchanger, and wherein when the valve assembly is in the heating mode the first three-way control valve is closed to the cool liquid conduit and open to the warm liquid conduit and the inlet of the circuit heat exchanger, and the second three-way control valve is closed to the warm liquid conduit and open to the cool water conduit and the outlet of the circuit heat exchanger. 
     
     
         5 . A system as claimed in  claim 1  wherein the valve assembly comprises a single four-way control valve having four ports and a rotary actuator, the four ports comprising a first port fluidly coupled to the warm liquid conduit, a second port fluidly coupled to an inlet of the circuit heat exchanger, a third port fluidly coupled to the cool liquid conduit, and a fourth port fluidly coupled to an outlet of the circuit heat exchanger, and wherein the rotary actuator fluidly couples the first and second ports and fluidly couples the third and fourth ports in the heating mode, and fluidly couples the first and fourth ports and fluidly couples the second and third ports in the cooling mode. 
     
     
         6 . A district energy sharing system comprising:
 a thermal energy circuit comprising
 a warm water conduit for flow of water therethough at a first temperature; 
 a cool water conduit for flow of the water therethrough at a second temperature that is lower than the first temperature; and 
 at least one circuit pump coupled to at least one of the warm and cool water conduits for pumping the water therethrough; 
   a grey water injection assembly comprising
 a grey water supply conduit fluidly coupled to the warm or cool water conduit and for fluidly coupling to a grey water source such that grey water is supplied to the warm or cool water conduit; and 
 a pressure control device fluidly coupled to the grey water supply conduit or thermal energy circuit and operable to regulate water pressure within the thermal energy circuit; 
   a client building heat transfer apparatus fluidly coupled to the warm and cool water conduits and for thermally coupling to a client building such that thermal energy can be transferred between the thermal energy circuit and the client building; and   a grey water take-off conduit fluidly coupled to the warm water conduit and for fluidly coupling to a client building such that grey water can be supplied to the building for non-potable uses.   
     
     
         7 . A system as claimed in  claim 6  wherein the grey water injection assembly further comprises a filtration device fluidly coupled to the grey water supply conduit upstream of the pressure control device. 
     
     
         8 . A system as claimed in  claim 6  wherein the pressure control device comprises at least one pump operable to increase the pressure of the grey water above the pressure of water in the thermal energy circuit. 
     
     
         9 . A system as claimed in  claim 8  wherein the pressure control device further comprises at least one control valve and a cushion tank fluidly coupled to the pump and operable to vary the flow rate of grey water to the warm water conduit. 
     
     
         10 . A system as claimed in  claim 6  further comprising a server plant comprising:
 a circuit heat exchanger thermally coupled to the thermal energy circuit and for thermally coupling to a heat source or a heat sink or both; 
 piping fluidly coupling the heat exchanger to the warm and cool water conduits; and 
 a pump coupled to the piping, and 
 
       wherein the grey water supply conduit is fluidly coupled to the piping. 
     
     
         11 . A system as claimed in  claim 6  wherein the grey water has a higher temperature than the water at the second temperature, and the grey water supply conduit is fluidly coupled to the warm water conduit. 
     
     
         12 . A district energy sharing system comprising:
 a first and a second thermal energy circuit each comprising
 a warm liquid conduit for flow of a heat transfer liquid therethough at a first temperature; 
 a cool liquid conduit for flow of the heat transfer liquid therethrough at a second temperature that is lower than the first temperature; and 
 a circuit pump coupled to at least one of the warm and cool liquid conduits for pumping the heat transfer liquid therethrough; and 
   a thermal energy transfer station for thermally coupling the first and second thermal energy circuits, and comprising at least one of a:
 liquid transfer assembly fluidly coupling the first and second thermal energy circuits and comprising a pump operable to flow heat transfer fluid therebetween; and 
 a heat exchanger assembly thermally coupling and fluidly separating the first and second thermal energy circuits. 
   
     
     
         13 . A system as claimed in  claim 12  wherein the thermal energy transfer station comprises only the liquid transfer assembly, which further comprises:
 a warm liquid transfer conduit fluidly coupling the warm liquid conduits of the first and second thermal energy circuits; 
 a cool liquid transfer conduit fluidly coupling the cool liquid conduits of the first and second thermal energy circuits; and 
 a changeover assembly comprising piping fluidly coupled to the warm or cool liquid transfer conduits and to the pump, and at least one control valve fluidly coupled to the piping and operable in a first mode which defines a fluid pathway through the piping from the first thermal energy to the second thermal energy circuit, and a second mode which defines a fluid pathway through the piping from the second thermal energy circuit to the first thermal energy circuit. 
 
     
     
         14 . A system as claimed in  claim 13  wherein the thermal energy transfer station comprises only the heat exchanger assembly, which comprises:
 a liquid-to-liquid heat exchanger having a first heat transfer zone and a second heat transfer zone thermally coupled to but fluidly separated from the first heat transfer zone; 
 first liquid transfer piping fluidly coupling the first heat transfer zone to the warm and cool liquid conduits of the first thermal energy circuit and second liquid transfer piping fluidly coupling the second heat transfer zone to the warm and cool liquid conduits of the second energy circuit; 
 a pair of transfer pumps each respectively fluidly coupled to the first and second liquid transfer piping and operable to flow liquid from the first thermal energy circuit through the first heat transfer zone, and to flow liquid from the second thermal energy circuit through the second heat transfer zone. 
 
     
     
         15 . A system as claimed in  claim 14  wherein the thermal energy transfer station further comprises a pressure control device and fluid conduit fluidly coupled to the first and second liquid transfer conduits, and operable to the regulate the pressure between the first and second thermal energy circuits, the pressure control device comprising at least one of a pressure reducing control valve and a booster pump. 
     
     
         16 . A system as claimed in  claim 14  wherein the thermal energy transfer station further comprises at least one server plant, each server plant comprising a heat pump assembly thermally coupling one of the first or second liquid transfer conduits to at least one of a heat source and a heat sink.