Design and Operation of Sustainable Systems

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Design and Operation of Sustainable Systems
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1. Introduction
A sun oriented focal recipient involves the utilization of a field of mirrors called heliostats
which are coordinated towards a collector which is at the highest point of a tower (Ho et al.
2017). The heliostats behave like an expansive allegorical reflector divided into little
portions. The recipient warms up in light of the approaching sun powered radiation liquid and
transmits warmth to a warmth exchange liquid which used to run a turbine. The idea of
sunlight based focal collector control plants exuded in Sandia National Laboratories in 1976
with the foundation of the National Solar Thermal Test Facility in Albuquerque, New
Mexico. From that point forward, a few pilot plant have been built worldwide with the
biggest one being the Solar One plant in Barstow, California. According to Ho et al. (2017),
Solar One covered an area of 72 acres of land with a reflective area of 39.9 m2 square meters
provided by each of the 1818 heliostats and produced 10MW of power it worked from 1982
to 1988 when Solar Two was built
Figure 1: Solar One. Source: (Ho et al. 2017)
Another one in operation is PS10 solar central receiver facility which operates in Spain. It
produces 11MW using its 624120 m2 heliostats pointed at the 115m high tower (Farges,
Bézian, & El Hafi 2018

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Figure 2:PS10 heliostat, Spain. Source: (Farges, Bézian, & El Hafi, 2018)
The main components of the power plants include the turbine, the tower, the receiver, and
heliostats. From these designs above, the mirrors are large and hence, difficult in cleaning,
and need a large land area to avoid shadowing and blocking. As compared to the proposed
design, they are more prone to wind load which can cause increased spillage in the receiver.
2. Selection of bearing diameter.
There is a desire to minimize the maintenance actions by with the trade-off with the size
of the bearing. The consideration is that the bearing should be big enough to last 25 years and
small enough to reduce power losses. A journal bearing is shown below
Figure 3: Bearing diametral features. Source (Khonsari & Booser 2017)
O’ – bearing centre

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O – journal centre
I – bearing length
d- journal diameter
D – bearing diameter
The key terms to consider in this case include
Diametral clearance which is the difference between the diameters of the journal and the
bearing. This can be calculated from the formula
c = D – d
The bearing’s diametric clearance, c, ought to be little enough to create the essential
speed inclinations with the goal that the weight develop will bolster the heap. Likewise, the
little freedom has favorable position of diminishing the side spillages (Khonsari & Booser
2017). In any case, the recompense should be made for assembling resistance in this diary
and bushing. The ordinarily utilized leeway in mechanical machines is 0.025mm per cm of
journal diameter.
Then there is the radial clearance which is the spacing between the radius of the
journal and that of the bearing. This can be expressed as shown:
c1= D−d
2 = c
2
The diametral clearance ratio is the ratio is = c/d.
Eccentricity is the ratio of the separation between the middle O of the bearing and the
dislodged focus O' of the bearing under burden. It is signified by e. The eccentricity
proportion is the proportion of the eccentricity to the clearance in the radius and can be
expressed mathematically as
Eccentricity ratio= e
c1
There is a distinction between a long and a short bearing. In the event that the
proportion of the journal’s length to the diameter (l/d) is short of one, at that point the bearing
is said to be a short bearing, but when it is more than one, it is called a long bearing
(Khonsari & Booser 2017). A square bearing is that one whose l/d proportion is unitary.