Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

A Thermofluid System
Srikanth Vedantam

1

Problem statement

You’ve been hired by a company that produces solar domestic water heaters
...
You and your team have been tasked with designing a system that
presses groundnuts to obtain oil using a solar thermal system
...

If you want to come up with the best solution to this problem, there are systematic
processes by which you can do innovative designs
...
Alternatives such as photovoltaic (PV) to obtain
electricity should also be studied and compared to this system in order to get the best
solution
...


2

Solar thermal system

Your design team has brainstormed to develop an initial prototype of the your product
...
Naturally
it may not even work or be the most efficient approach
...
Various aspects of this system can be
refined going forward
...
Naturally, availability of manufacturing
processes and materials and overall cost will also play important considerations in a
successful design
...
This
energy will be used to run an engine which would either produce electricity or perform
some other sort of useful work
...
We could consider storing the heat
energy and run the engine during the evening and night or we could consider storing the
electricity produced in a chemical battery and use it when there is no sunlight
...


8

T,w

2

7

1

3

5

4

6

Figure 1: A schematic of a proposed solar thermal system
Let’s now try to describe the various subcomponents of the solar thermal system in
slightly more detail:
1
...
The advantages of having it would be that we can
achieve higher temperatures but the disadvantages would be the cost
...
This adds a layer of complexity and cost
...
Solar collector: A working fluid is expected to pass through this device and collect
the heat from the concentrated sunlight
...

3
...
We have to decide what
the optimal material would be
...
The material of the working fluid will affect the dimensions and
configuration of the whole device
...
Energy storage device: We will try to store a part of the heat energy so that
we can use it later in evening and night
...
Stirling engine: Let’s assume we will use a stirling engine to extract useful work
from the high temperature working fluid
...
But how will we design it? What should be
its dimensions? How can we optimise its size and configuration?
6
...
What should be its temperature and
size? Why do we even need it?
7
...
Overall piping: What should be the configuration and dimensions of the piping of
the entire system so that we can minimize the cost and losses?
As we go forward, we will take up each of the subcomponents and try to examine
what principles we need to apply in order to design and optimize each of them
...


3

Overall energy and power analysis

We must first begin with an understanding about how much energy and power we will
require
...
Since
our system is meant to power a typical home in Chennai, we will try to first get an
understanding of the power and energy requirements
...
Then we can estimate the power requirement and the time of
use during the day
...

Alternatively, we can try to look at at the current electricity bill for a typical home
and knowing the cost per unit of electricity (1 unit = 1 kWhr), we can decide the total
energy requirement per day
...

The second aspect of importance is the peak power requirement
...
For example, a water
heater might be switched on for about hour per day
...
Mixers and grinders also have peak power requirements
which are very high but are used for short times
...

3

We will have to think very carefully about how we would accomplish the requirements
of peak power
...
Normally the way the peak power requirement is accounted for is to put some
storage into the system
...
But let’s say that the filtration system in their house is only able to supply 1 litre
per hour
...

In the case of electricity requirements for a house, the electric supply grid itself could
be considered such a storage device
...
Statistically since different users be staggering their
peak power requirements, the average power requirement and peak power requirements
will not be too different
...
Calculate the power and energy required for your home based on power rating of
all the electric devices and the amount of time they are used
...
Estimate the power and energy required for a farmer to pump ground water to
irrigate their field
...
Estimate the power and energy required by a sugarcane farmer who wants to add
value to their farm by producing sugarcane juice from their yield
...
You’ve identified a remote hill in the outskirts of Chennai
...
What would be the power
and energy requirements for this?
5
...
What should be the rating of the refrigerator?
6

---