U.S. patent application number 11/492626 was filed with the patent office on 2008-03-20 for method and apparatus for solar energy storage system using gas and rock.
Invention is credited to Yanong Zhu.
Application Number | 20080066736 11/492626 |
Document ID | / |
Family ID | 39187267 |
Filed Date | 2008-03-20 |
United States Patent
Application |
20080066736 |
Kind Code |
A1 |
Zhu; Yanong |
March 20, 2008 |
Method and apparatus for solar energy storage system using gas and
rock
Abstract
A method and Apparatus for solar energy storage system uses gas
for thermal transport for central tower solar thermal electric
power plant to provide high quality, low cost, and continuously
electric power generation. The storage contains a number of storage
modules that each module can store energy for a given period of
time. The thermal energy from central tower charges the modules one
by one during the sunny time, while the thermal electric power
plant discharge the modules one by one as long as it works. A
control and a connection valve system control and connect the
charge and discharge modules with the central tower and the power
plant according to pre-arranged sequences. Fans at the cool side of
the storage system push the circulation gas into the central tower
or the thermal storage modules. In the discharge system, the hot
gas from storage system is send to the heat exchange system, and to
generate steam and to super heat steam for the power plant. In the
charge system, the cold gas is pushed into the central receiver
thermal exchange unit and to be heated, and the hot gas is then
circulated back to storage system to charge up the storage
system.
Inventors: |
Zhu; Yanong; (Santa Clara,
CA) |
Correspondence
Address: |
Yanong Zhu;Suite 100-3C
2900 Gordon Avenue
Santa Clara
CA
95051
US
|
Family ID: |
39187267 |
Appl. No.: |
11/492626 |
Filed: |
July 25, 2006 |
Current U.S.
Class: |
126/620 |
Current CPC
Class: |
Y02E 60/142 20130101;
Y02E 10/46 20130101; F03G 6/065 20130101; Y02E 70/30 20130101; F03G
6/005 20130101; F28D 20/0056 20130101; Y02E 60/14 20130101; F24S
20/20 20180501; F24S 80/20 20180501 |
Class at
Publication: |
126/620 |
International
Class: |
F24J 2/34 20060101
F24J002/34 |
Claims
1. A solar energy thermal storage system contains at the least two
thermal storage modules and a thermal storage charge system and
discharge system; (a) A thermal storage module is made of small
rocks in a large sealed, thermal isolated container for thermal
storage and gas freely flow between rocks for the thermal
transport; (b) A thermal charge system and discharge system can
select to charge and discharge thermal storage modules at the same
time, and are controlled by the thermal storage charge and
discharge controller; (c) A charge and discharge controller is
programmed in such a way that allows the maximizing the thermal
energy storage from central solar tower while discharge the thermal
energy to the power plant as smooth as possible; (d) A monitoring
system for charge and discharge system with sensors is monitoring
the temperature of the rocks, the gas, and as well the pressure,
and the contaminations of the gas; (e) A filter system in the gas
loop is used to filtering out the dusts or other un-wanted
compounds of the gas; (f) An heat exchanger with the hot liquid
metal transport solar thermal energy from the solar central
receiver on one side is heating the charging gas on the other side;
(g) A gas loop circulation fan is installed at the cool side of the
charging gas loop and another is installed at the cool side of the
discharging loop;
2. The solar energy thermal storage system of claim 1 wherein said
thermal storage modules means a large size container filled with
rocks of suitable sizes with cool gas in and out pipe from one side
and hot gas in and out pipe from another side, and covered with
thermal isolation material. The cold gas pipe and hot gas pipe of
the container are connected with valves that the storage unit can
switch the connections between the charge and discharge system,
3. The solar energy thermal storage system of claim 1 wherein said
a charge system has hot side and cold side pipes and valves which
allow each storage unit connect to or cut off from the charge
system, and at the cold side, a fan blows the cooler gas to the
central solar tower receiver's heat exchange and push the hot gas
out from the hot side of the exchange, and circulating back to
thermal storage unit's hot side;
4. The solar energy thermal storage system of claim 1 wherein said
a discharge systems have hot side and cold side pipes and valves
which allow each storage unit connect to or cut off from the
discharge system, and at the cold side, a fan flows cooler gas to
thermal storage and push the hot gas out from the hot side of the
thermal storage unit and send to the heat exchange of the power
plant for power generation;
5. The solar energy thermal storage system of claim 1 wherein said
a thermal storage charge and discharge controller contains electric
valves, computers, and sensors, and sensors monitoring the status
of the thermal storage units, computers analyzing the data from the
sensors, and valves connect the thermal storage units on or off or
partial open and partial close from the charge system and on or off
from the discharge system;
6. The solar energy thermal storage system of claim 1 wherein said
a discharge systems have filters installed at the output of the
system to protect the heat exchangers. The filters filter dusts
being based on gravity and centrifuge force.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention generally relates to solar thermal energy
storage by using rock or other type of solid storage media and use
gas, liquid metal, and steam as the thermal transfer media.
[0003] 2. Description of Prior Art
[0004] The differences between the nature characters of the solar
energy and power grid requirement require thermal storage to buffer
and temperature store energy. The nature characters of the solar
energy are not service on demand while the power grid requires
backbone power plant supply electricity to the grid must be service
on demand. The solution for meeting the service on demand
requirements is the thermal energy storage system.
[0005] The thermal energy storage system stores the excessive
thermal energy to thermal storage during sunshine time and less
electric demanding time, and release the stored thermal energy when
the power plant is demanding.
[0006] In additional to meet the requirement of service on demand
to the power grid, the power plant utilization is also the key to
power plant economy. The thermal storage system can significantly
increase the utilization factor of the power plant; therefore
increase the financial performance of the power plant.
[0007] A number of the energy storage methods are commonly using
today, such as battery, flywheel, pumped water hydro power plant,
direct steam storage, molten salt, molten salt and rocks, oil and
rocks, and etc. None of them can meet the large-scale power grid
storage requirements for low cost, less location dependency, high
reliability, high efficiency, and environment friendly.
[0008] The lead acid battery is not economical for power gird
energy storage plus the short lifetime and un-friendly to natural
environment.
[0009] Flywheel has limited capacity, cost, and reliability issue
when apply to large-scale grid power storage.
[0010] Pumped water hydro power plant is the most practical way for
large grid scale energy storage, but the availability of suitable
land for power plant is very limited.
[0011] Direct steam storage is simple, but it is limited by the
capacity when come to grid scale power plant.
[0012] Molten salt thermal storage system presented a method for
thermal storage. But it faces several major disadvantages, such as
low maximum temperature or high freezes temperature, corrosive
nature, high power requirement for circulations, and expensive
storage medium.
[0013] Oil, or oil and rock, or molten salt and rock methods are
suffered from limitation on higher temperature, pollutions, and
high cost on heat transport medium.
BRIEF SUMMARY OF THE INVENTION
[0014] A method and Apparatus for solar energy storage system uses
gas for thermal transport and uses rock for thermal storage medium
for central tower solar thermal electric power plant to provide
high quality, low cost, and continuously electric power
generation.
[0015] The storage contains a number of storage modules that each
module can store energy for a given period of time. The thermal
energy from central tower charges the modules one by one during the
sunny time, while the thermal electric power plant discharge the
modules one by one during the power generation hours.
[0016] The thermal energy stored in the thermal storage can also be
used heat the liquid metal or molten salt of the solar receiver
during the time the sun is not available.
[0017] A control system and connection valves switch the
connections for each storage module between the charge system and
the discharge system according to the sensor readings, computer
operation models and running experiences.
[0018] For charging a storage module, the storage module has to be
connected to the charge system through the controlling valves, a
fan at the cold side of the charge system push the circulation gas
from the cool end of the storage module into the central tower's
thermal exchanger, and the heated gas from the exchanger then
returning to hot side of the charge system and pushed to the hot
end of the thermal storage module and entering the thermal storage
module and dissipate the thermal energy to rocks until the gas
cooled down reach the cold side of the charge system to complete
the circulation cycle.
[0019] For discharging a storage module, the storage module has to
be connected to the discharge system through the controlling
valves; a fan at the cold side of the discharge system blows the
cold gas into the cold end of the thermal storage module. The gas
will be heated through the heat exchange with the rocks and then
pushed out through the hot end of the thermal storage module. The
hot gas is then pass through the thermal exchange system that
generates steam, super heat and reheat the steam, until the gas is
cool down and return to cold side of the discharge system to
complete the circulation cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] This invention consists in the construction, arrangements
and combination of the various parts of the device, whereby the
objects contemplated are attained as hereinafter more fully set
forth, specifically pointed out in the claims, and illustrated in
the accompanying drawings in which:
[0021] FIG. 1 is a illustration of the central tower solar power
plant of this invention. The central solar tower receives the
concentrated solar energy, the transported by liquid metal or
molten salt to heat exchanger to heat the gas. The gas from the
exchanger transports the thermal energy to the thermal storage
system. The output of the hot gas from the thermal storage system
is sent to steam generation, super heating, and reheating for
driving the turbine to generate electricity.
[0022] FIG. 2 is a schematic of the thermal charge system. Only one
thermal storage module (for example number 1) is connected to the
charging system for charging. The rest of storage modules are
disconnected from the charging system by switch off the valves, and
ready for discharging if they are charged.
[0023] FIG. 3 is a schematic of the thermal discharge system. Only
one thermal storage module (for example number N) is connected to
the discharging system for discharging. The rest of the storage
modules are disconnected from the discharging system by switch off
the related valves and ready for charging if they have been
discharged.
[0024] FIG. 4 is an illustration of a thermal storage module in
charge mode. The hot gas flow in the storage module from the hot
end, and then exchange the thermal energy with the rocks and been
cooled down and exit from cold end of the thermal storage module.
When all rocks are heated, the storage module is full. The charging
system will switch off the valves that connected to this module and
starting charge other discharged modules.
[0025] FIG. 5 is an illustration of a thermal storage module in
discharge mode. The cold gas enters the thermal storage module from
the cold end, and absorbs thermal energy from rock and exit from
the hot end.
[0026] FIG. 6 is an illustration of a gas filter. The gas enters
the filter and slows down by the dividers to allow gravity and
centrifuge force to draw the dusts down to the dusts collectors.
The dusts collectors can be emptied once they are full.
DETAILED DESCRIPTION OF THE INVENTION
[0027] This invention is generally related to a method and
Apparatus for solar energy storage system uses gas for thermal
transport and uses rock for thermal storage medium for central
tower solar thermal electric power plant to provide high quality,
low cost, and continuously electric power generation.
[0028] The thermal storage system as illustrated by FIG. 1 contains
the thermal charge system 112,108,109, and 110, and the thermal
discharge system 104,105, and 106, and the thermal storage modules
107.
[0029] The thermal charge system charges the thermal storage
modules while the discharge system discharge the thermal storage
modules. A thermal storage module is connected to charge system for
charge and connected to discharge system for discharge. The valves
connected at the hot end and the cold end of a thermal storage
module can switch the connections of the storage module between the
charge and discharge system following the controls of the thermal
storage system controller.
[0030] The blower fans 106 and 109 force the working gas to
circulate in both charge and discharge systems.
[0031] The heat exchangers at charge system 108 and discharge
systems 104 provide bridges between different working fluids with
different physical parameters for central receiver and power
plant.
[0032] The filters 110 and 105 keep the dusts away from entering
the heat exchangers cause excessive ware or clotting.
[0033] FIG. 1 is an illustration of the central tower solar power
plant of this invention. The central solar tower 112 receives the
concentrated solar energy, and the thermal energy from receiver is
transported by liquid metal or molten salt to heat exchanger 108 of
charge system. The blower 109 pushes the cold gas from the charge
system into exchanger 108. In the exchanger, the liquid metal or
molten salt exchange the heat to the gas. The hot liquid metal or
molten salt come in the exchanger and cold liquid metal or molten
salt come out the exchanger. The coal gas pushed by blower enters
the exchanger and absorb the heat and become hot gas and then exit
the exchanger. The cold liquid metal or molten salt is then
circulating back to the receiver and the heated gas is circulating
back to charge system.
[0034] At the least one of the thermal storage module is connected
to the charge system if the charge system is working.
[0035] The hot gas from the charge system exchanger is send to the
connected thermal storage module 107. The hot gas 401 enters the
thermal storage module and exchanges the heat with the rocks 405
inside of the thermal storage module as illustrated by FIG. 4.
After the gas cooled down by leave the heat with the rocks, it then
exit the thermal storage module at the cold end 403.
[0036] Before the hot gas entering the exchanger, it is filtered by
the gravity and centrifuge and gravity filter to remove the dusts
as illustrated by FIG. 6.
[0037] A thermal storage module is a long container filled with
rocks with average dimension optimized according to the design
parameters. The mass of the thermal storage module is large enough
that during charge period of started with an empty module, the cold
end output gas maintained at cold, while the hot end maintained at
hot during the discharge period.
[0038] At the least one of the thermal module 21001 as illustrated
by FIG. 2 is connected to the discharge system for power plant to
generate power.
[0039] During the discharge cycle, the blower 312 pushes the cold
gas 504 as illustrated by FIG. 5 entering the thermal storage
module 307nn, where the cold gas receives the heat from rocks 505
until reaching the hot working temperature, and stabilized with the
rock temperature. The hot gas from the output of the thermal
storage module will be pushed into the power plant heat exchanger
309. The power plant heat exchanger consists of boiler, super
heater and re-heater for steam turbine, and heaters and re-heaters
for gas turbine. The gas from thermal storage will exchange its
thermal energy with working medium of steam turbine or gas turbine
until cooled down. The cold gas is then send back to blower for
next circulation cycle.
[0040] The thermal storage system contains more than two thermal
storage modules that each module can store energy for a given
period of time. At the least one of the module is in charge mode
during the sunny time, and at the lease one of the module is in
discharge mode during the power generation time. The storage
capacity of each thermal storage module is determined by the
optimization between the pressure required to push gas through with
give speed, the heat exchange area of the rocks required to heat up
and stabilize the temperature of the circulation gas, and thermal
storage capacity.
[0041] The thermal energy residuals of the thermal storage modules
will be used heat the liquid metal or molten salt of the solar
receiver during the time the sun is not available.
[0042] The thermal storage control system switches the valves that
connect the storage module between the charge and the discharge
sub-system according to the sensor readings, computer operation
models and running experiences.
[0043] The gas filters use the gravity, dividers and centrifuge
force to separate the dusts from the gas. At the bottom of the
filters, the dusts can be removed regularly from the filters.
* * * * *