r [001] LINEAR CAVITY RECEIVER FOR LINEAR FRESNE REFLECTOR
SOLAR ENERGY COLLECTOR SYSTEM
[002] FIELD OF THE INVENTION
[003] Embodiments of the present invention in general relate to a linear
fresnel reflector solar energy collector system, and in particular relates to a
linear cavity receiver for generating direct high temperature super-heated
steam using a secondary reflector and evacuated tube collector for the
linear fresnel reflector solar energy collector system.
[004] BACKGROUND
[005] Solar power generation has been considered a viable source to help
provide for energy needs in a time of increasing consciousness of the
environmental aspects of power production. Solar energy production relies
mainly on the ability to collect and convert energy freely available from the
sun and can be produced with very little impact on the environment. Solar
power can be produced without creating radioactive waste as in nuclear
power production, and without producing pollutant emissions including
greenhouse gases as in fossil fuel power production. Solar power
production is independent of fluctuating fuel costs and does not consume
non-renewable resources.
[006] Solar power generators generally employ fields of controlled mirrors,
to gather and concentrate sunlight on a receiver to provide a heat source
for power production. A solar receiver typically takes the form of a panel of
1
r tubes conveying a working fluid there through. Previous solar generators
have used working fluids such as molten salt because it has the ability to
store energy, allowing power generation when there is little or no solar
radiation, such as at night time. The heated working fluids are typically
conveyed to a heat exchanger where they release heat into a second
working fluid such as air, water, or steam. Power is generated by driving
heated air or steam through a turbine that drives an electrical generator.
[007] Such conventional methods and systems for solar power generation
have generally been considered satisfactory for their intended purpose.
However, there is still a need in the art for systems and methods for solar
power generation that allow for improved efficiency and decreased heat
loss.
[008] SUMMARY
[009] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system and a linear
cavity receiver for generating direct high temperature super-heated steam
using a secondary reflector and evacuated tube collector for the linear
fresnel reflector solar energy collector system.
[010] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy boiler system including one
or more primary reflectors which are arranged in parallel to each other with
respect to each other.
r [011] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy boiler system that includes
one or more primary reflectors which are arranged in parallel to each other,
and further the one or more primary reflectors laterally connected to each
other with respect to each other.
[012] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system that
includes one or more primary reflectors and a linear cavity receiver, for
generating direct high temperature super-heated steam, using a compound
parabolic secondary reflector and an evacuated tube collector.
[013] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system and a linear
cavity receiver, for generating direct high temperature super-heated steam,
using a compound parabolic secondary reflector made of glass with high
temperature protective silver coating, and is clamped with provision for
thermal expansion.
[014] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system and a linear
cavity receiver, for generating direct high temperature super-heated steam,
wherein the linear cavity receiver (LCR) houses a steel support structure, a
secondary reflector (SR), and an evacuated tube collector (ETC) with solar
selective absorber coating.
4
[015] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system and a linear
cavity receiver, for generating direct high temperature super-heated steam,
wherein the linear cavity receiver is positioned substantially at eight
millimeters above the reflectors plane.
[016] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system and a linear
cavity receiver, for generating direct high temperature super-heated steam,
wherein the linear cavity receiver support structure is designed to hold the
secondary reflector and the absorber tube in place such that the spatial
coordinates are maintained during operation. In an embodiment, the
secondary reflector and the absorber tube has provision for
accommodating thermal expansion.
[017] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system and a linear
cavity receiver, for generating direct high temperature super-heated steam,
wherein the profile of the secondary reflector is designed such that the
reflected sunlight from the one or more primary reflectors is reflected on to
the absorber tube throughout the day.
[018] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system and a linear
cavity receiver, for generating direct high temperature super-heated steam,
wherein the secondary reflector is not rigidly clamped but held in position
5
r by one or more supports from a support structure such that the one or more
primary reflectors are allowed to freely move during thermal expansion.
[019] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system and a linear
cavity receiver, for generating direct high temperature super-heated steam,
wherein the secondary reflector has a profile that can be manufactured
from material selected from a group comprising reflective aluminum,
stainless steel sheet, and glass. In an embodiment, the aluminum or
stainless steel sheet can be manufactured by cold rolling process for
achieving the whole profile.
[020] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system and a linear
cavity receiver, for generating direct high temperature super-heated steam,
wherein the evacuated tube collector is clamped from its bottom end and
the thermal expansion mechanism incudes one or more rollers running
along two channels.
[021] According to an embodiment of the present invention there is
provided a linear fresnel reflector solar energy collector system and a linear
cavity receiver, for generating direct high temperature super-heated steam,
wherein the secondary reflector is made from glass material and is
designed as two symmetric halves, and the absorber tube clamping is
provided from the top of the support structure. The absorber tube clamp is
allowed to roll on a rail provided above the secondary reflector when the
absorber tube expands due to thermal expansion. This provides a freedom
to clamp the absorber tube rigidly as well as freedom to expand.
[022] According to an embodiment of the present invention there is
provided a direct saturated and superheated steam generating linear
fresnel reflector solar energy boiler system that includes one or more
primary reflectors. The one or more primary reflectors are mounted on one
or more axles wherein the one or more axles rest on one or more rollers
that facilitate and support axial rotation.
[023] According to an embodiment of the present invention there is
provided a direct saturated and superheated steam generating linear
fresnel reflector solar energy boiler system that includes one or more
primary reflectors wherein the one or more primary reflectors are mounted
on one or more axles, and wherein each of the one or more axles includes
axle plates.
[024] According to an embodiment of the present invention there is
provided a direct saturated and superheated steam generating linear
fresnel reflector solar energy boiler system that includes at least one linear
cavity receiver. The at least one linear cavity receiver houses a single
evacuated tube collector and one or more primary reflectors, wherein the
one or more primary reflectors concentrates the sunlight on to an
evacuated tube collector and thereby increasing the concentration ratio.
[025] According to an embodiment of the present invention there is
provided a direct saturated and superheated steam generating linear
n
f fresnel reflector solar energy boiler system for generating useful heat in the
form of saturated or/and superheated steam by concentrating sunlight on to
a single row of one or more evacuated receiver tube collectors housed
along with one or more primary reflectors inside a receiver support
structure.
[026] According to an embodiment of the present invention there is
provided a direct saturated and superheated steam generating linear
fresnel reflector solar energy boiler system that includes a configuration
having a single row of evacuated receiver tube collectors and one or more
secondary reflectors that increases the concentration ratio (total mirror
aperture width to absorber tube aperture width) and hence the operation
parameters (temperature and pressure of steam).
[027] According to an embodiment of the present invention there is
provided a direct saturated and superheated steam generating linear
fresnel reflector solar energy boiler system that includes an absorber tube
that is maintained in vacuum during operation, and hence the heat loss is
reduced and the efficiency is increased considerably.
[028] According to an embodiment of the present invention there is
provided a direct saturated and superheated steam generating linear
fresnel reflector solar energy boiler system that includes a single row of
evacuated receiver tube collector configuration that simplifies the process
line and instrumentation thereby reducing the cost and operation
procedure.
«
r [029] These and further aspects which will be apparent to the expert of the
art are attained by a direct saturated and superheated steam generating
linear fresnel reflector solar energy boiler system in accordance with the
main claim.
[030] BRIEF DESCRIPTION OF THE DRAWINGS
[031] So that the manner in which the above recited features of the present
invention can be understood in detail, a more particular description of the
invention, briefly summarized above, may be had by reference to
embodiments, some of which are illustrated in the appended drawings. It is
to be noted, however, that the appended drawings illustrate only typical
embodiments of this invention and are therefore not to be considered
limiting of its scope, for the invention may admit to other equally effective
embodiments.
[032] Figure 1 illustrates a perspective view of a Linear Fresnel Reflector
(LFR) system according to an embodiment of the present invention;
[032] Figure 2 illustrates a perspective view of a linear cavity receiver
support structure for a Linear Fresnel Reflector (LFR) system according to
an embodiment of the present invention; and
r [033] Figure 3 illustrates a partial view of the linear cavity receiver support
structure for the Linear Fresnel Reflector (LFR) system according to an
embodiment of the present invention; and
[034] Figure 4 illustrates a front view of the linear cavity receiver support
structure for the Linear Fresnel Reflector (LFR) system according to an
embodiment of the present invention.
[035] To facilitate understanding, identical reference numerals have been
used, where possible, to designate identical elements that are common to
the figures. It is to be noted, however, that the appended drawings illustrate
only typical embodiments of this invention and are therefore not to be
considered limiting of its scope, for the invention may admit to other equally
effective embodiments.
[036] DETAILED DESCRIPTION OF THE DRAWINGS
[037] Figure 1 to 4 illustrates various views and components of a Linear
Fresnel Reflector (LFR) system according to an embodiment of the present
invention. The Linear Fresnel Reflector (LFR) solar energy collector system
includes a linear cavity receiver 405. The linear cavity receiver 405 houses
a secondary reflector 401 and an evacuated absorber tube collector (single
tube collector) 400.
[037] The Linear Fresnel Reflector (LFR) solar energy collector system
further includes a reflector unit. In an embodiment, the reflector unit
includes one or more primary reflectors 200 are arranged in parallel with
respect to each other, and each of the one or more primary reflectors 200
are placed at a proximate distance (a gap) with respect to the ground. The
gap is so chosen that the shadow of the one or more primary reflectors 200
is not casted on adjacent primary reflectors of the one or more primary
reflectors 200 at least for a particular hour angle.
[038] The one or more primary reflectors 200 are mounted on
corresponding one or more axles. The one or more axles rest on
corresponding one or more rollers for supporting axial rotation. The one or
more rollers are coupled laterally using a steel hollow section (connecting
arm) and connected by one or more levers (tracking arm). In an
embodiment, each of the one or more axles comprises an axle plate which
is configured to accommodate the corresponding one or more tracking
arms for each row of the one or more primary reflectors. The axle plates
are configured to rest on a roller v-block and further clamped from its top
portion with another set to aid rotation and support during upward loads
due to wind.
[039] In an embodiment, the linear cavity receiver (LCR) 405 Is placed at 8
m above the plane of the secondary reflector 401. The linear cavity receiver
405 support structure 405 is designed to hold the secondary reflector 401
f l
and the evacuated tube collector 400 in place such that the spatial
coordinates of the secondary reflector 401 and the evacuated tube collector
400 are maintained during operation. The secondary reflector 401 and the
evacuated tube collector 400 are also designed to have a provision for
accommodating thermal expansion.
[040] In an embodiment, the profile of the secondary reflector 401 is
designed such that the reflected sunlight from the one or more primary
reflectors 200 is reflected on to the absorber tube throughout the day.
Further the secondary reflector 401 is not rigidly clamped but held in
position by supports from the support structure 405 of the linear cavity
receiver 400 such that the secondary reflector 401 material Is allowed to
freely move during thermal expansion. The support structure 404 is
provided with bulk heads 403 at both the ends for fastening multiple
receivers longitudinally. Further, the angle supports 402 are also welded to
the bulk head 403 for clamping on to the A - frame.
[041] In an embodiment, the secondary reflector 401 profile is further
manufactured on reflective aluminum or stainless steel sheet or glass.
Further the aluminum or stainless steel sheet can be manufactured by cold
rolling process for achieving the whole profile of the secondary reflector
401. Herein, the absorber tube is clamped from it's bottom end and the
thermal expansion mechanism consists of rollers running along two
channels provided at the bottom.
\l~
[042] In an embodiment of the present invention the ganged tracking
system depicted in above figures facilitates the decrease in the errors and
the cost per module as the number of the plurality of primary reflectors and
an area covered by the one mechanical tracking system is higher
compared to the previous configuration. Further, Linear Cavity receiver
structure houses the secondary reflector and the evacuated absorber tube
collector and is fixed at an optimum height from the secondary reflector.
Also, the Linear Cavity receiver is stationary and is internally provided with
a mechanism for allowing thermal expansion of the ETC.
[043] While the foregoing is directed to embodiments of the present
invention, other and further embodiments of the invention may be devised
without departing from the basic scope thereof, and the scope thereof is
determined by the claims that follow.
)3

CLAIMS:
1. A linear fresnel reflector solar energy boiler system comprising:
one or more primary reflectors, wherein the one or more
primary reflectors are arranged in parallel to each other;
a linear cavity receiver, wherein the linear cavity receiver
comprises at least one secondary reflector, a support structure, and
an evacuated tube collector, and wherein the linear cavity receiver is
configured for generating direct high temperature super heated
steam using at least the secondary reflector and the evacuated tube
collector.
2. The linear fresnel reflector solar energy boiler system of claim 1,
wherein the support structure is made from steel.
3. The linear fresnel reflector solar energy boiler system of claim 1,
wherein the at least one secondary reflector is a compound
parabolic secondary reflector.
4. The linear fresnel reflector solar energy boiler system of claim 1,
wherein the at least one secondary reflector is made of glass with
ORIGINAL
0 '013 ^-ify ii
high temperature protective silver coating clamped with provision for
thermal expansion.
5. The linear fresnel reflector solar energy boiler system of claim 1,
wherein the evacuated tube collector is clamped from its bottom end
with the provision for thermal expansion by having a thermal
expansion mechanism comprises rollers running along two
channels.
6. The linear fresnel reflector solar energy boiler system of claim 1,
wherein the one or more primary reflectors are laterally connected to
each other.
7. The linear fresnel reflector solar energy boiler system of claim 1,
wherein the one or more primary reflectors are mounted on one or
more axles.
8. The linear fresnel reflector solar energy boiler system of claim 7,
wherein the one or more axles rest on one or more rollers that
facilitates and supports axial rotation.
9. The linear fresnel reflector solar energy boiler system of claim 7,
wherein each of the one or more axles comprises axle plates, and
wherein the axle plates of each of the one or more axles are
15
y
ORIGIN/^ g^ I? i l U 2=^ ^ 1 ^
10 m MW
configured to accommodate a tracking arm for each row of the one
or more primary reflectors.