Method and apparatus for combined heat and power generation

Abstract

A temperature control apparatus for a building, the apparatus comprising: an electricity generator, operable to contribute to an electrical power supply for consumer appliances at the building; a heat transfer circuit adapted to circulate heat transfer fluid to cool the electricity generator; a heating system comprising a heat source for providing heat energy to a space heater for heating at least one zone of the building and to a hot water tank arranged to store a supply of hot water for the building, and a heat exchanger adapted to supplement the heat energy from the heat source with heat energy obtained from the heat transfer circuit; a user interface adapted to enable a user to select at least one of (a) a desired temperature for the at least one zone of the building, and a first time period during which the desired temperature is to be maintained; and (b) a second time period for the supply of hot water from the hot water tank; and the apparatus further comprising: a controller configured to determine when to operate the electricity generator based on at least one of: (i) the thermal capacity of the hot water tank; and (ii) the first time period, the desired temperature and the current temperature of the at least one zone of the building.

1 . A temperature control apparatus for a building, the apparatus comprising:
 an electricity generator, operable to contribute to an electrical power supply for consumer appliances at the building;   a heat transfer circuit adapted to circulate heat transfer fluid to cool the electricity generator;   a heating system comprising a heat source for providing heat energy to a space heater for heating at least one zone of the building and to a hot water tank arranged to store a supply of hot water for the building, and a heat exchanger adapted to supplement the heat energy from the heat source with heat energy obtained from the heat transfer circuit;   a user interface adapted to enable a user to select at least one of
 (a) a desired temperature for the at least one zone of the building, and a first time period during which the desired temperature is to be maintained; and 
 (b) a second time period for the supply of hot water from the hot water tank; 
   
       and the apparatus further comprising:
 a controller configured to determine when to operate the electricity generator based on at least one of:
 (i) the thermal capacity of the hot water tank; and 
 (ii) the first time period, the desired temperature and the current temperature of the at least one zone of the building. 
 
 
     
     
         2 . The apparatus of  claim 1  wherein the controller is configured to operate both the electricity generator and the heat source prior to the first time period, to achieve the desired temperature in the at least one zone of the building at the start of the first time period. 
     
     
         3 . The apparatus of  claim 1  or  2  in which the controller is configured to operate the electricity generator to generate electricity during a preheat phase to preheat at least a part of the space heater before switching on the heat source. 
     
     
         4 . A temperature control apparatus for a building, the apparatus comprising:
 an electricity generator, operable to contribute to an electrical power supply for electrical appliances at the building;   a heat transfer circuit adapted to circulate heat transfer fluid to cool the electricity generator;   a heating system comprising a heat source for providing heat energy to a space heater for heating at least one zone of the building and a heat exchanger adapted to supplement the heat energy from the heat source with heat energy obtained from the heat transfer circuit;   a user interface adapted to enable a user to select a desired temperature for the at least one zone of the building, and a first time period during which the desired temperature is to be maintained;   
       and the apparatus further comprising:
 a controller configured to operate the electricity generator alone during a pre-heat period in which heat energy obtained from the heat transfer circuit is used to pre-heat the space heater, and to operate the electricity generator and heat source together until the at least one zone achieves the desired temperature. 
 
     
     
         5 . The apparatus of  claim 4  wherein the heat source is configured to provide heat to a hot water tank arranged to store a supply of hot water for the building, and the controller is configured to determine when to operate the electricity generator based on at least one of:
 (i) the thermal capacity of the hot water tank; and 
 (ii) the first time period, the desired temperature and the current temperature of the at least one zone of the building. 
 
     
     
         6 . The apparatus of  claim 2 ,  3  or  5  wherein the controller is configured to obtain a first signal based on the temperature of the at least one zone of the building and a second signal based on the rate of change of said temperature, and to select when to switch on the heat source based on the first signal, the second signal, and the desired temperature. 
     
     
         7 . The apparatus of any of  claim 1  to  3 ,  5  or  6  wherein the controller is configured to operate the electricity generator in the event that the thermal capacity of the hot water tank is greater than a selected threshold level. 
     
     
         8 . The apparatus of any of  claims 1  to  3  wherein the controller is configured to operate the electricity generator based on a user command, and in which the apparatus is configured to override the user command based on at least one of:
 (a) the thermal capacity of the hot water tank; and 
 (b) the first time period, the desired temperature and the current temperature of the at least one zone of the building. 
 
     
     
         9 . The apparatus of any of  claims 1  to  8  comprising a communications interface adapted to communicate over a network with a remote device, and to override a user command for the electricity generator based on a message received from the remote device. 
     
     
         10 . The apparatus of any of  claims 1  to  9  wherein the apparatus comprises a serial communications interface adapted to communicate signals between the controller and the heating system according to a first protocol, and a protocol converter coupled to communicate commands from the controller to the electricity generator according to a second protocol. 
     
     
         11 . A temperature control apparatus for a building, the apparatus comprising:
 an electricity generator, operable to contribute to an electrical power supply for electrical appliances at the building;   a heat transfer circuit adapted to circulate heat transfer fluid to cool the electricity generator;   a heating system comprising a heat source for providing heat energy to a space heater for heating at least one zone of the building and a heat exchanger adapted to supplement the heat energy from the heat source with heat energy obtained from the heat transfer circuit;   a user interface adapted to enable a user to select a desired temperature for the at least one zone of the building, and a time period for which the desired temperature is to be maintained;   a controller configured to operate the electricity generator to generate electricity and to preheat the space heater using the heat exchanger and to obtain a first signal based on the temperature of the at least one zone of the building and a second signal based on the rate of change of the temperature and to determine when to switch on the heat source based on the user selected time period, the desired temperature, the first signal and the second signal.   
     
     
         12 . The apparatus of  claim 11  further comprising the features of any of  claims 1  to  10 . 
     
     
         13 . A power distribution control apparatus comprising:
 a plurality of combined heat and power, CHP, systems each installed at a separate dwelling;   a communications interface arranged to communicate over a network with the plurality of CHP systems; and   a controller, coupled to the communications interface for communicating with the plurality of CHP systems,   wherein the controller is operable to send a command, via the communication interface, to operate a first CHP system installed at a first dwelling and the controller is configured to control the first CHP system based on at least one of:
 (a) a condition of an electrical power supply at a second dwelling; and 
 (b) a generalised grid condition. 
   
     
     
         14 . The apparatus of  claim 13  wherein the controller is configured to control the first CHP system to generate electrical power based on data describing a time dependent thermal demand at the first dwelling. 
     
     
         15 . The apparatus of  claim 13  or  14  in which the controller is configured to send commands to CHP systems in a first geographical location to operate a selected number of CHP systems in the first geographic location to generate electrical power, and to determine the selected number based on at least one message received, via the communications interface, from at least one CHP system at a second geographic location. 
     
     
         16 . The apparatus of  claim 13  or  14  wherein the controller is configured to select particular CHP systems to be operated based on a number of switching cycles of the particular CHP systems. 
     
     
         17 . The apparatus of any of  claims 13  to  16  wherein the controller is configured to select the particular CHP systems to be operated based on at least one of:
 (a) a programmed start time of the particular CHP systems; and 
 (b) a thermal capacity associated with the particular CHP systems. 
 
     
     
         18 . The apparatus of  claim 16  wherein the controller is configured to obtain data indicating a thermal capacity associated with a particular CHP system based on a message received, via the communications interface, from the particular CHP system. 
     
     
         19 . The apparatus of  claim 18  wherein obtaining data indicating thermal capacity comprises estimating based on thermal demand information and at least one of a time of day, a time of year, and a current temperature. 
     
     
         20 . The apparatus of any of  claims 13  to  19  wherein at least one of the CHP systems is configured to provide at least one of a frequency and a voltage of the electrical power supply at the dwelling to the controller to indicate the condition of the electrical power supply at the dwelling. 
     
     
         21 . A combined heat and power apparatus for a dwelling, the apparatus comprising:
 an electricity generator, operable to contribute to an electrical power supply for consumer appliances in the dwelling;   a heat transfer circuit adapted to circulate heat transfer fluid to cool the electricity generator and to contribute to the heating requirements of the dwelling;   a user interface adapted to enable user control of the electricity generator; and   a controller configured to communicate with a remote device over a network to receive commands for controlling the electricity generator and to override the user's control of the electricity generator in response to a received command.   
     
     
         22 . The apparatus of  claim 21  wherein the controller is configured to transmit a message to the remote device, the message comprising data indicating at least one of a frequency and voltage of the electrical power supply to the dwelling. 
     
     
         23 . The apparatus of  claim 21  or  22  wherein the controller is configured to transmit a message to the remote device indicating one of: a thermal capacity of the dwelling; a current thermal demand of the dwelling; and a time dependent thermal demand of the dwelling. 
     
     
         24 . A method of controlling a heating and power generation apparatus for a building, wherein the apparatus comprises a heat source and an electricity generator adapted to generate electricity to contribute to an electrical power supply at the building and to provide thermal energy to the building, the method comprising:
 obtaining data describing a desired temperature of at least one zone of the building;   selecting a first thermostatic set point associated with the desired temperature;   monitoring a temperature of the at least one zone; and   operating the electricity generator and the heat source together in the event that the temperature is less than the first thermostatic set point and operating the electricity generator alone in the event that the temperature is greater than the first thermostatic set point.   
     
     
         25 . The method of  claim 25  comprising switching off the electricity generator in the event that the temperature is greater than a second thermostatic set point. 
     
     
         26 . The method of  claim 24  or  25  wherein the apparatus comprises a thermal store, the method comprising operating the electricity generator and the heat source together to provide thermal energy to the thermal store in the event that the temperature of the thermal store is less than a third thermostatic set point and operating the electricity generator alone in the event that the temperature of the thermal store is greater than the third thermostatic set point. 
     
     
         27 . The method of  claim 26  comprising switching off the electricity generator in the event that the temperature is greater than a fourth thermostatic set point. 
     
     
         28 . The method of any preceding claim comprising selecting at least one of the set points to reduce the number of times the electricity generator is switched on and off in a given period of time. 
     
     
         29 . The method of any preceding claim comprising selecting at least one of the set points to extend the time period of operation of the electricity generator. 
     
     
         30 . The method of any of  claims 24  to  29  wherein the thermal store comprises a hot water tank adapted to store and dispense hot water in the building. 
     
     
         31 . The method of any preceding claim comprising selecting the set point at which the heat source is switched on in order to reduce the number of times the electricity generator is switched on and off in a given period of time. 
     
     
         32 . The method of any preceding claim comprising selectively diverting heat output from the electricity generator to one of the thermal store and a space heating system of the building to avoid the need to switch the electricity generator off. 
     
     
         33 . The method of any of  claims 24  to  32  comprising overriding a user control to operate the electricity generator. 
     
     
         34 . A temperature control apparatus for a building, the apparatus comprising:
 an electricity generator, operable to contribute to an electrical power supply for electrical appliances at the building;   a heat transfer circuit adapted to circulate heat transfer fluid to cool the electricity generator;   a heating system comprising a heat source for providing heat energy to a space heater for heating at least one zone of the building and a heat exchanger adapted to supplement the heat energy from the heat source with heat energy obtained from the heat transfer circuit; and   a controller adapted to divert heat energy obtained from the heat transfer circuit to one of the space heater and a thermal store of the building to extend a duration of operation of the electricity generator without exceeding a selected threshold temperature of the thermal store or the at least one zone of the building.   
     
     
         35 . The apparatus of  claim 34  wherein the controller is configured to divert heat energy obtained from the heat transfer circuit to the thermal store in the event that the temperature of the at least one zone of the building exceeds a first thermostatic set point. 
     
     
         36 . The apparatus of  claim 34  or  35  wherein the controller is configured to divert heat energy obtained from the heat transfer circuit to the space heater in the event that the temperature of the thermal store exceeds a second thermostatic set point. 
     
     
         37 . The apparatus of any of  claims 34  to  36  wherein the controller is configured to determine whether to divert heat energy obtained from the heat transfer circuit to the space heater or to the thermal store based on a user specified thermal demand in the building. 
     
     
         38 . The apparatus of  claim 37  wherein the controller is configured to determine the thermal demand based at least partly on a temperature outside the building. 
     
     
         39 . The apparatus of any of  claims 34  to  38  wherein the thermal store comprises a hot water tank adapted to store and dispense hot water for use in the building 
     
     
         40 . The apparatus of any of  claims 34  to  39  wherein the controller is configured to operate the electricity generator according to different thermostatic set points than the heat source.