U.S. patent application number 15/512391 was filed with the patent office on 2017-08-24 for method and apparatus for combined heat and power generation.
The applicant listed for this patent is British Gas Trading Limited. Invention is credited to Lee Christian BARLOW, William James KEOWN, Nicholas O'MALLEY, Adrian Robin RICHARDSON.
Application Number | 20170241650 15/512391 |
Document ID | / |
Family ID | 51869134 |
Filed Date | 2017-08-24 |
United States Patent
Application |
20170241650 |
Kind Code |
A1 |
RICHARDSON; Adrian Robin ;
et al. |
August 24, 2017 |
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.
Inventors: |
RICHARDSON; Adrian Robin;
(Windsor, Berkshire, GB) ; O'MALLEY; Nicholas;
(Windsor, Berkshire, GB) ; BARLOW; Lee Christian;
(Windsor, Berkshire, GB) ; KEOWN; William James;
(Windsor, Berkshire, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
British Gas Trading Limited |
Windsor, Berkshire |
|
GB |
|
|
Family ID: |
51869134 |
Appl. No.: |
15/512391 |
Filed: |
September 17, 2015 |
PCT Filed: |
September 17, 2015 |
PCT NO: |
PCT/GB2015/052694 |
371 Date: |
March 17, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F24D 19/1069 20130101;
F24D 3/08 20130101; F24D 12/02 20130101; F24D 2200/29 20130101;
G05D 23/1904 20130101; F24D 2200/26 20130101; Y02E 20/14 20130101;
G05D 23/1924 20130101; Y02B 30/14 20130101; F24D 19/1066 20130101;
G05D 23/1923 20130101; Y02B 30/00 20130101; G05D 23/1931 20130101;
F24D 3/082 20130101; F24D 3/02 20130101; F24D 19/1081 20130101 |
International
Class: |
F24D 19/10 20060101
F24D019/10; F24D 3/08 20060101 F24D003/08; F24D 12/02 20060101
F24D012/02; F24D 3/02 20060101 F24D003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2014 |
GB |
1416531.0 |
Claims
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.
Description
FIELD OF INVENTION
[0001] The present disclosure relates to alternative energy
provision, and more particularly to combined heat and power
generation apparatus such as may be used to heat buildings and
contribute to the supply of electrical power to those
buildings.
BACKGROUND
[0002] There is an increasing need for energy efficiency, both to
address the problems of climate change and to reduce the cost to
consumers of heating buildings and of providing electrical power in
those buildings.
[0003] It has been proposed to use combined heat and power
apparatus, CHP, in both domestic and commercial buildings, which
contribute both to meeting the demands for electrical power in the
building and to heating the building. In some circumstances CHP
apparatus may produce sufficient electrical power to meet the
supply needs of the building and to feed power back into the
electrical power grid. If increasing numbers of CHP systems are
installed, and begin to feed electrical power into the grid, they
may become a significant source of power. The grid itself will also
become more complex, with regions of the grid acting as sources of
electrical power at some times, and as sinks of electrical power at
other times.
[0004] To achieve the best efficiency from CHP apparatus it is
desirable to use both the electrical power and the heat generated
by the apparatus in the building in which it is installed.
[0005] The demand for heating in buildings is subject to daily and
seasonal variations. Demand for electrical power also varies in a
similar periodic or quasi periodic fashion in individual buildings
and there are also other short and long term temporal variations in
demand for electrical power. Where large numbers of buildings are
coupled to a common electrical power supply grid these fluctuations
in demand may place the supply grid under strain and degrade the
quality of the electrical supply, for example causing reduction in
voltage levels or variations in the frequency of an AC mains power
supply signal. These problems may affect geographic locations
differently. The degree and nature of these effects may depend on
the availability of electrical power, the local capacity of the
supply network, and the local demand for electricity.
[0006] Peaks and troughs in demand for electrical power may be
correlated to some degree with the demand for heating, but the
degree of correlation is not sufficient alone to permit electricity
suppliers to rely upon CHP contributions to address consumer demand
for electrical power. The present disclosure aims to address these
and related technical problems.
SUMMARY OF INVENTION
[0007] Aspects and embodiments of the invention are set out in the
appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0008] Embodiments of the invention will now be described, by way
of example only with reference to the accompanying drawings, in
which:
[0009] FIG. 1 illustrates a combined heat and power apparatus;
and
[0010] FIG. 2 illustrates a system for controlling electricity
supplies comprising a power distribution control apparatus and a
plurality of CHP systems.
[0011] In the drawings like reference numerals are used to indicate
like elements.
SPECIFIC DESCRIPTION
[0012] FIG. 1 shows a temperature control apparatus for a building
10. The apparatus comprises an electricity generator 26 arranged to
contribute to the electrical power supply 28 available to a
consumer at the building 10. The electricity generator 26 may also
be operable to feed electrical power back into the electricity
supply grid. As explained in more detail below, the apparatus also
comprises a controller 16 configured to determine the timing of
operation of this electricity generator 26 based on the thermal
capacity of the hot water tank 18 and/or the demand for space
heating in the building 10. The apparatus shown in FIG. 1 includes
a heating system having a space heater 20 and a hot water tank 18.
The heating system also has a heat exchanger 24 arranged to
supplement heat provided by the heating system's own heat source 22
with excess heat obtained by cooling the electricity generator
26.
[0013] The heating system's heat source 22 may comprise a fuel
burner for example a gas or oil fired boiler. The heat source 22 is
coupled to a space heater 20, which may comprise fluid filled
radiators for heating one or more zones of the building 10. The
heat source 22 is also coupled to heat water to be stored in the
hot water tank 18. The hot water tank 18 is arranged to store, and
to dispense, a supply of hot water for use by a consumer in the
building 10.
[0014] A heat transfer circuit is arranged to circulate a heat
transfer fluid around an engine of the electricity generator 26 to
remove excess heat from the generator, and to provide the heat
transfer fluid to the heat exchanger 24, which may be arranged
inside the building 10, for example the heat exchanger 24 may be
arranged in a zone of the building 10 which is at least partially
heated by the heating system. The heat transfer fluid may comprise
a fluid with a melting point of less than zero degrees centigrade,
for example the heat transfer fluid may comprise glycol.
[0015] The heat exchanger 24 is coupled to the heating system and
adapted to supplement the heat energy from the heat source 22 with
heat energy obtained from the heat transfer circuit.
[0016] The heating system comprises a user interface 12 to enable a
user to select a desired temperature for the building 10. The user
interface may comprise a human input device such as buttons,
switches, a touch screen or a pointing device, and one or more
output devices such as a screen or other display means. For
example, the user interface 12 may be arranged to allow a user to
select a desired temperature for a particular zone of the building
10 such as a room or collection of rooms. Generally the user
interface 12 is also operable to select at least one first time
period during which the desired temperature is to be
maintained--for example the user interface 12 may be operable by a
user to select a start and a duration or end time for the space
heating. Generally, when operating the space heating, a consumer
may select a time period in the morning, and perhaps also another
time period later in the day during which a desired temperature is
to be maintained. The user interface 12 may also be operable to
allow a user to specify at least one second time period during
which the consumer wishes to be able to dispense hot water from the
hot water tank 18.
[0017] The hot water tank 18 has a certain thermal capacity
associated with the quantity of water that the tank 18 is able to
store, the fill level of the tank 18 at any given time, and the
temperature of the water in the tank 18.
[0018] The hot water tank 18 may comprise one or more sensors
arranged to provide fill level and temperature signals to the
controller 16 to enable the controller 16 to determine the thermal
capacity of the tank 18 and/or the thermal demand associated with
meeting the consumer's demand for hot water. The heating system may
also comprise one or more temperature sensors arranged to provide
signals to the controller 16 indicating the temperature of one or
more zones of the building 10 and perhaps also the temperature
outside the building 10. In the interest of clarity these sensors
are not illustrated in FIG. 1.
[0019] The controller 16 may be coupled to a communications
interface 14 for communicating over a network such as a wireless
and/or wired network such as a local area network (LAN) which may
be coupled to a wide area network, for example a telecommunications
network, for example the internet, for communicating with a remote
device, for example a device in a different geographical location
than the building 10. The controller 16 may also be configured to
communicate with one or more of the other components of the
apparatus shown in FIG. 1 via this communications interface 14 for
example over the LAN and/or via a serial communications BUS which
may operate according to a MODBUS protocol. The electricity
generator 26 may be configured to report data such as voltage and
frequency available at the mains electricity supply 28 in the form
of a CANBUS message, and the controller of the CHP system may be
configured to translate the data from CANBUS to another protocol
such as MODBUS. The controller may also be configured to receive a
MODBUS command, for example from the user interface 12 or in the
form of a message received over the communications interface 12,
and to translate the MODBUS message into a CANBUS command to start
or stop operation of the electricity generator 26. The MODBUS
interface may comprise MODBUS RTU (serial), but in some embodiments
may also comprise MODBUS over a data network protocol such as IP
and/or TOP data networks.
[0020] The controller 16 may be adapted to report the thermal
capacity of the building 10--for example the thermal capacity of
the hot water tank 18 and/or the thermal demand associated with the
space heating to a remote device via this communications interface
14. The controller 16 may also be adapted to obtain data from the
electricity generator 26 indicating the voltage and/or frequency of
the external mains electricity supply to the building 10.
[0021] The controller 16 is configured to obtain data indicating
the thermal capacity of the hot water tank 18, for example it may
be configured to determine this based on the sensor signals from
the hot water tank 18. It is also configured to determine a thermal
demand of the space heating. This determination may be based on one
or more of the sensor signals, the desired temperature for the zone
(or zones) of the building 10 associated with these temperature
sensor signals, and the time period during which the consumer has
selected that this temperature is to be maintained.
[0022] In operation of the hot water system, the controller 16
obtains data indicating the thermal capacity of the hot water tank
18, and provided that the thermal capacity of the hot water tank is
greater than a selected threshold level, the controller 16 switches
on the electricity generator 26 and operates the heat exchanger 24
to heat water to be stored in the hot water tank 18, this threshold
level may be selected based on the heat output of the heat
exchanger 24 to ensure that the electricity generator 26 is
switched on for a time period at least 1 minute, for example at
least 5 minutes, for example at least 30 minutes in order to fulfil
the thermal capacity of the hot water tank 18. The controller may
also obtain data indicating that the thermal capacity of the hot
water tank has been exceeded (e.g. the water is over temperature),
or that the thermal capacity is less than a selected threshold
level and, may determine based on this data to switch off the
electricity generator 26.
[0023] In order to balance the geographical distribution of power
supply electricity grid, the controller 16 may receive a command to
switch off the electricity generator 26, for example the command
may be received from a remote device via the communications
interface 14. The controller 16 may respond to this command by
determining whether the quantity of hot water stored in the hot
water tank 18 is sufficient to meet the user's requirements, and in
the event that it is not, the controller 16 may switch on the heat
source 22 to heat hot water for the hot water tank 18.
[0024] In operation of the space heating system, prior to the start
of a first time period during which the user has selected a desired
temperature for a zone of the building 10, the controller 16
switches on the electricity generator 26 and uses the heat
exchanger 24 to at least partially preheat the space heater 20
and/or the zone of the building 10.
[0025] The controller 16 may then identify when the temperature of
the space heater 20 and/or the zone of the building 10 has reached
an equilibrium state, for example based on detecting that the rate
of change of temperature is less than a selected threshold or by
operating the electricity generator 26 and heat exchanger 24 for a
selected duration.
[0026] At the end of this preheat phase, and prior to the start of
the first time period, in the event that the temperature of the
zone remains less than the desired temperature, the controller 16
may operate both the electricity generator 26 and the heat source
22 together to heat the zone. The switch on time of the generator
and heat source 22 for this dual-heating period may be selected to
achieve the desired temperature of the zone at the start of the
first time period.
[0027] Whilst, as mentioned above, the controller 16 may be
configured to receive commands to switch off the electricity
generator 26 during this dual-heating phase, the controller 16 may
also be configured to increase the duration of operation of the
electricity generator 26. For example towards the end of the
dual-heating (ramp-up) heating phase, as the zone approaches the
desired temperature, the controller 16 may be configured to switch
off the heat source 22 of the heating system prior to switching off
the electricity generator 26 whilst continuing to monitor the
temperature (and perhaps also the rate of change of temperature) in
the zone of the building 10. The controller 16 may then determine
whether it is possible to continue to run the electricity generator
26 without overshooting the desired temperature--for example the
electricity generator 26 may be run at all times when space heating
is desired.
[0028] Embodiments of the system illustrated in and described with
reference to FIG. 1 may be used to provide a power distribution
control apparatus adapted to supplement and control electrical
power supply, for example to accommodate localised variations in
power demands placed on the supply grid.
[0029] One such apparatus is illustrated in FIG. 2. The apparatus
shown in FIG. 2 comprises a distributed network of CHP systems
30-1, 30-2, 30-3, 30-4, 32-1, 32-2, 32-3, 32-4 each installed at a
separate dwelling to generate electrical power to contribute to the
electrical power supply at the dwelling.
[0030] The supply grid illustrated in FIG. 2 comprises a power
station 38 coupled by conductors 36 (e.g. cables) to provide
electrical power to a plurality of substations 34, 40, 42. The CHP
systems illustrated in FIG. 2 are all coupled to the power supply
grid 34, 36, 38, 40 which may extend over a wide geographical area
(e.g. most or all of a nation). The grid comprises a high-voltage
electric power transmission network 36, and connects power stations
38 and the substations 34, 40, 42, to ensure that electricity
generated in one geographic location can be used to satisfy demand
elsewhere.
[0031] For example, the subset of CHP systems 30 at a first set of
dwellings in a first geographical location may be coupled to the
power supply grid by a first substation 34 whilst a second subset
of CHP systems 32 at a second set of dwellings may be coupled to
the power supply grid by a second substation 40. Variations in the
demand for electrical power at the first set of dwellings 30 may
have an impact on the voltage and/or frequency of the supply to
those dwellings, but may also affect the supply to other dwellings
for example such as the second set of dwellings 32.
[0032] The power distribution control apparatus shown in FIG. 2
comprises a controller 160 and a communications interface 140
arranged to allow the controller 160 to communicate over a network
with the plurality of CHP systems.
[0033] The communications interface 140 of the controller 160
illustrated in FIG. 2 may comprise a server having a wired or
wireless interface adapted to send and receive messages over a
telecommunications network, for example over the Internet, to
selected ones and/or to selected subsets, of the CHP systems.
[0034] The CHP systems 30, 32 are each adapted to provide data to
the controller 160 indicating the voltage and or frequency of the
power supply obtainable from the power supply grid by the CHP
system. Some or all of the CHP systems may each be adapted to
provide data to the controller 160 indicating the thermal capacity
available at the dwelling at which they are installed, for example
a thermal capacity associated with a hot water tank 18 of the
dwelling and/or the thermal capacity and/or thermal demand
associated with a space heating system. They may also be configured
to provide data indicating the thermal demand of the space heating
system as a function of time--for example based on a user selected
program comprising periods of operation, desired temperature. The
CHP systems may also be adapted to provide data indicating
temperature in at least one zone of the dwelling and/or an external
temperature.
[0035] The controller 160 is configured to monitor frequency of the
AC voltage provided by the grid, for example by monitoring the
supply from one or more substations and/or by monitoring the
frequency of the voltage measured by one or more CHP systems. The
controller 160 may be configured to ensure that the frequency
remains within 0.5 Hz of 50 Hz.
[0036] The controller 160 may be configured to store data
indicating the time dependent thermal demand and/or thermal
capacity of a plurality of the dwellings, and to determine based on
this data a series of subsets of the CHP systems that are available
at any particular time to offer increased generation (or reduced
demand from the dwelling), and the time for which this facility can
be maintained. For example the controller 160 may identify a first
subset of CHP systems that can be operated to generate electricity
to reduce demand for a minimum of 15 minutes without exceeding the
thermal demand and/or thermal capacity of the dwelling in which
they are installed. This first subset of CHP systems may then be
used to provide a fast reserve in the event of fluctuation of the
frequency of power supply of more than 0.5 Hz. The controller 160
may also determine, based on this time dependent thermal demand
and/or thermal capacity data, a second subset of CHP systems that
are able to deliver power (or reduce consumption) within five
minutes automatically, or seven minutes of a manual instruction,
and to be maintained for a minimum of four hours. This second
subset of systems may be used to provide a fast start reserve. In
this way collections of CHP systems distributed in consumer
dwellings may be operated to provide a virtual power plant.
[0037] To implement this, the controller 160 is configured to
obtain data indicating the thermal demand associated with one or
more of the dwellings, for example indicating the thermal demand as
a function of time. This data may also comprise an indication of
the thermal capacity available at one or more of the dwellings, for
example the thermal capacity available by topping up a hot water
tank 18 at the dwelling. Some or all of this data may be provided
in messages received from the CHP systems. Some or all of this data
may be provided locally in a data store, for example it may be
predetermined or based on seasonal or historic variations and may
comprise estimates. The controller 160 may also be adapted to
obtain data indicating generalised grid conditions, such as low
voltage or excessive voltage in particular geographical locations
for example in locations associated with one or more substations of
the grid. This data may be obtained based on user input and/or
based on monitoring or telemetry data received from other devices
in the power supply grid.
[0038] The controller 160 is also operable to send a message
comprising a command to switch a CHP system on to generate
electricity, and to send a message comprising a command to switch a
CHP system off. The controller 160 may be configured to send a
common message to a selected subset of the CHP systems, and may
also be configured to select this subset based on data obtained
from the CHP systems.
[0039] In one mode of operation, the controller 160 monitors a
generalised grid condition by obtaining data indicating the voltage
of a power supply provided by a particular substation. In the event
that the data indicates that the supply voltage at the substation
is less than a target voltage, the controller 160 determines the
voltage change that would be required of the input supply, provided
to the substation, for the output supply provided from the
substation to meet this target. The controller 160 may then select
a subset of the CHP systems that can be activated to generate
electrical power and/or to shed load from the associated dwellings
in order to raise the voltage at that substation towards the target
voltage. This subset of CHP systems may be selected based on the
time of day (and/or time of year) and data indicating the time
dependent thermal demand and/or thermal capacity of the dwellings
associated with those CHP systems. This provides one way to operate
a CHP system installed at a first dwelling based on a generalised
grid condition.
[0040] In another mode of operation, the controller 160 monitors
condition of electrical supply at a first dwelling, and controls
the operation of an electricity generator 26 of a CHP system at one
or more other dwellings based on this condition. For example a CHP
system at a first dwelling may report the voltage and/or frequency
of the power supply from the grid at the dwelling to the controller
160. In the event that the voltage or frequency is outside a target
range (for example within 1% of target value) the controller 160
sends a command to one or more other CHP systems in order to modify
the voltage and/or frequency of the supply at the first dwelling
toward the target range. The one or more other CHP systems may be
selected based on the time of day (and/or time of year) and data
indicating the time dependent thermal demand and/or thermal
capacity of the dwellings associated with those CHP systems. It is
mentioned above that data indicating the quality of electrical
supply (e.g. voltage or frequency) may be obtained from a CHP
system, but it will be appreciated that some or all of this data
may also be obtained from an electricity meter coupled to the CHP
system.
[0041] The controller 160 may select the electricity generators
that are to be operated at other dwellings based on electrical
demand at those dwellings, for example the controller may be
configured to switch on an electricity generator in a second
dwelling that is coupled to the same or a related supply (e.g. to
the same substation) as the first dwelling in order to shed load
from that second dwelling, the second dwelling may be selected
based on electrical demand at that dwelling.
[0042] The commands sent by the controller 160 to the CHP systems
may be configured to override a user specified control set by the
consumer using a user interface 12 at the dwelling. This may be
used by the controller 160 to send commands to CHP systems in a
first geographical location to operate CHP systems in that
geographic location (for example CHP systems coupled to a common
substation) to generate electrical power.
[0043] The controller 160 may determine the number of substations
based on a message (or messages) received from CHP systems at a
second geographic location (e.g. coupled to a different
substation). The controller 160 may do this to shed load from this
second substation to allow the voltage at the first substation to
be raised towards the target level.
[0044] Other features and modes of operation may be used with the
system illustrated in FIG. 2. As one example, the controller 160
may be configured to select particular CHP systems to avoid
switching on a CHP system that will need to be switched off again
shortly afterwards, for example the controller 160 may select only
CHP systems that can be run for more than a selected minimum
duration, or choose to extend the operating duration of one or a
group of CHP systems rather than bringing others online in order to
meet the demands of the grid with the smallest number of switching
of be operated based on a number of switching cycles of the CHP
systems. The controller 160 may be configured to store data
indicating the number of switching cycles of one or more of the CHP
systems.
[0045] The above embodiments are to be understood as illustrative
examples. For example, the dwelling described with reference to
FIG. 2 may be any kind of building such as commercial premises.
[0046] As another example, in some embodiments the controller 160
is configured to obtain data indicating a shortfall of electricity
in an area of the grid, for example in the supply from one or more
substations, and to respond to that shortfall by identifying a
number CHP systems coupled to that supply and which (a) are not
producing electricity at that time and (b) are located in dwellings
where the thermal capacity of the building enables activation of
the CHP system without increasing the temperature of the building
beyond a selected threshold level. This threshold level may be set
by a user command, or it may be specified by the controller 160. In
some examples the controller is configured to identify these CHP
systems based on temperature signals obtained from the dwellings in
which they are located. This may enable CHP systems in dwellings
where the temperature is below threshold (e.g. 17.degree. C. or
lower) to be activated to generate electricity and to be switched
off when they raise the temperature in the dwelling above the
threshold (e.g. to 18.degree. C. or more). This may have the
advantage of allowing load shedding, or additional generation
capacity in the grid.
[0047] As another example, thermal and/or electrical demands may
vary as a function of time, as explained above, and may be defined
by a user program of a thermostat (e.g. via a user interface and
controller such as that described above with reference to FIG. 1).
In addition to user specified demands such as these however, the
controller 160 illustrated in FIG. 2 may be configured to determine
thermal demand based on a temperature difference between the
internal and external parts of a building, for example based on
temperature data obtained from sensors at the building, the
temperature difference may also be determined based on regional
statistics, for example based on general, regional temperature
measurements. For example a common external temperature may be used
to determine the temperature difference for a set of dwellings in a
common geographic area. The controller may also store data
describing the power required to maintain temperature at a
particular dwelling, or at a group of dwellings, and this may
comprise a relationship such as the power per unit temperature of
temperature difference between internal and external temperatures.
The controller may be configured to select CHP systems to switch on
to shed load as described above based on this stored data, and
internal/external temperature data relating to the same dwellings
and/or based on user heating programs which may be defined by a
user program of a thermostat (e.g. via a user interface and
controller such as that described above with reference to FIG.
1).
[0048] Heating and power generation apparatus of the present
disclosure may operate using different thermostatic set points for
the electricity generator and the heat source (e.g. the boiler).
The apparatus may be configured to operate the electricity
generator as much as possible whilst staying within the desired
temperature bounds of the building. For example, a first
thermostatic set point may be selected based on a desired
temperature of a zone of a building. The controller may monitor a
temperature of the zone and operate the electricity generator and
the heat source together in the event that the temperature is less
than the first thermostatic set point. The controller may be
configured so that the electricity generator is operated alone
(e.g. the heat source is switched off) in the event that the
temperature exceeds that first thermostatic set point provided that
the temperature is less than a second thermostatic set point.
[0049] The controller may be configured to provide heat energy into
a thermal store, such as a hot water tank or phase change material,
PCM, store on similar criteria. For example the controller may be
configured to operate 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. The controller may be configured so
that the electricity generator is operated alone (e.g. the heat
source is switched off) in the event that the temperature of the
thermal store is greater than the third thermostatic set point
provided that the temperature of the thermal store is less than a
fourth thermostatic set point.
[0050] These thermostatic set points may be selected to reduce the
number of times the electricity generator is switched on and off in
a given period of time. For example the set points may be selected
based on known thermal rise or fall times of the building, or known
response times of the heat source and/or space heating, or known
thermal losses of a zone of the building, for example based on a
power loss per unit temperature difference between internal and
external temperature.
[0051] Further embodiments are envisaged. It is to be understood
that any feature described in relation to any one embodiment may be
used alone, or in combination with other features described, and
may also be used in combination with one or more features of any
other of the embodiments, or any combination of any other of the
embodiments. Furthermore, equivalents and modifications not
described above may also be employed without departing from the
scope of the invention, which is defined in the accompanying
claims. For example, in some embodiments thermal stores such as
storage heaters and/or phase change material thermal stores may be
used in addition to or as an alternative to hot water tanks. As
another example it will be appreciated that data may be received
from, and output to a user, by means of any suitable controller,
for example the user interface of FIG. 1 (and one or more aspects
of the controller) may be provided by a user carried (e.g.
handheld) electronic device such as a Wi-Fi.RTM. enabled device or
a telecommunications device such as a smartphone or tablet.
[0052] With reference to the drawings in general, it will be
appreciated that schematic functional block diagrams are used to
indicate functionality of systems and apparatus described herein.
It will be appreciated however that the functionality need not be
divided in this way, and should not be taken to imply any
particular structure of hardware other than that described and
claimed below. The function of one or more of the elements shown in
the drawings may be further subdivided, and/or distributed
throughout apparatus of the disclosure. In some embodiments the
function of one or more elements shown in the drawings may be
integrated into a single functional unit.
[0053] In some examples, one or more memory elements can store data
and/or program instructions used to implement the operations
described herein. Embodiments of the disclosure provide tangible,
non-transitory storage media comprising program instructions
operable to program a processor to perform any one or more of the
methods described and/or claimed herein and/or to provide data
processing apparatus as described and/or claimed herein.
[0054] The activities and apparatus outlined herein may be
implemented using controllers and/or processors which may be
provided by general purpose computers configured as described
above, or by fixed logic such as assemblies of logic gates or
programmable logic such as software and/or computer program
instructions executed by a processor. Other kinds of programmable
logic include programmable processors, programmable digital logic
(e.g., a field programmable gate array (FPGA), an erasable
programmable read only memory (EPROM), an electrically erasable
programmable read only memory (EEPROM)), an application specific
integrated circuit, ASIC, or any other kind of digital logic,
software, code, electronic instructions, flash memory, optical
disks, CD-ROMs, DVD ROMs, magnetic or optical cards, other types of
machine-readable mediums suitable for storing electronic
instructions, or any suitable combination thereof.
* * * * *