1. Utilization of Solar Energy by Non-conventional Methods
L R Raviteja Krovvidi, (raviteza88@gmail.com)
6th semester, B.Tech, EEE. (09843557280)
Jitesh Mathur, (jiteshmathur2006@vit.ac.in)
6th semester, B.Tech, EEE. (09944353256)
VIT UNIVERSITY, VELLORE.
---------------------------------------------------------------------------------------------------------------------
ABSTRACT:
In this project study, various Solar technologies have been discussed which are feasible
both technically and economically. Strictly speaking, the economics has to be improved a long
way before mass commercialization of solar products can occur. Nevertheless, the time is ripe
for alternate sources of energy before we destroy this planet or exhaust the fossil fuels.
Preserving the ecology and environment is a moral imperative rather than an economic equation.
Solar energy is one of key alternatives available for free of cost, which should be utilized
effectively to reduce the human footprint on environment.
CONTENTS:
1 INTRODUCTION
2 SOLAR AIR CONDITIONING & REFRIGERATION
2.1 DIRECT & THERMO-MECHANICAL
2.2 ABSORPTION & ADSORPTION AIR CONDITIONING / REFRIGERATION
2.3 HYBRID PHOTOVOLTAIC/THERMAL (PV/T) SYSTEMS
3 CONCLUSION
REFERENCES

2. 1. INTRODUCTION tank storage. This eliminates the motor
pump all together. Similarly all the wastes
The implementation of solar materials of the house hold can be fermented
technologies in daily life has become an to produce bio-gas which can supplement
extreme need of the hour. Though cooking gas if not completely eliminate it.
intermittent, solar energy cannot be
discarded completely and it particularly suits 2 SOLAR AIR CONDITIONING &
Indian climate where long and clear daylight REFRIGERATION
is abundant. It can be implemented in almost
all parts of India particularly in plateaus It is interesting to note that the same
which have hot tropical climate throughout solar energy, which is stored as heat, can
the year. also be used for air conditioning purposes.
Solar air conditioning and refrigeration has a
huge potential but relatively, a less exploited
Any house in India generally has the area. In fact, utilizing solar energy for air
following load requirements. conditioning drastically reduces the load on
1. Lighting the grid, especially in summer. It can be
2. Air conditioning (Heating & Cooling implemented at any scale, the bigger the
depending on climate) better. The cost of installation is paid back
3. Refrigeration in a couple of years and moreover there are
4. Motor pump no electricity charges. Also maintenance is
5. TV etc. less compared to present vapour
compression systems. There are many ways
It is important to note that lighting, of implementing air conditioning through
air conditioning and refrigeration account to solar energy. The following section
more than 80% of the total load. discusses them in detail.
Interestingly all these loads can be sufficed
through solar power. In fact, by proper 2.1 DIRECT & THERMO-
design of the house itself, these load MECHANICAL TYPE
requirements can be minimized. Such
designs are called passive solar designs. In In direct method, a solar photo-
general, people discuss about solar energy in voltaic cell is coupled with dc motor which
terms of the amount of heat or electricity runs the compressor of the AC. This
generated from it. But the same solar energy generates cooling effect. But the inherent
can also be used for cooling purposes by disadvantages like cost, vaable speed
various advanced techniques like sorption compressors etc are unfavorable for this
refrigeration. This greatly reduces the type.
electricity demand on the grid and its In thermo-mechanical systems
consequences. Also the availability of solar evacuated tube or parabolic collectors are
power coincides with the load requirements coupled with Rankine or Sterling engine to
in particular seasons. generate electricity, which can drive the
It is always best to implement solar vapor compressor. Alternatively, a Sterling
technologies in conjugation with other refrigerator (heat engine operated in reverse)
renewable sources like wind, biomass etc for can also be designed which directly
better operations. For example, a wind based produces cooling effect. This is also
water pump can be implemented for water expensive and rather complicated.

3. 2.2 ABSORPTION & ADSORPTION
AIR CONDITIONING /
REFRIGERATION
Sorption air conditioning is the most
promising of all the air conditioning
techniques available at present. Not only it is
simple in design, it is also economical.
These systems work on the principle of
adsorption.
Sorption refrigeration uses physical
or chemical attraction between a pair of
substances to produce refrigeration effect. A
sorption system has a unique capability of
transforming thermal energy directly into
cooling power. Among the pair of
substances, the substance with lower boiling
temperature is called sorbate and the other is
called sorbent. The sorbate plays the role of
refrigerant.
Absorption refers to a sorption
process where a liquid or solid sorbent
absorbs refrigerant molecules into its inside
and changes physically and/or chemically in
the process. Adsorption, on the other hand,
involves a solid sorbent that attracts
refrigerant molecules onto its surface by
physical or chemical force and does not
change its form in the process. refrigerant vapour from the evaporator
rejecting the sorption heat Qa to ambient. In
WORKING: The component where sorption the evaporator, the liquefied refrigerant from
takes place is denoted as absorber and the the condenser evaporates removing the heat
one where desorption takes place is denoted Qe from the cooling load.
as generator. The generator receives heat Qg The working heat is supplied from
from the solar collector to regenerate the the collectors. The water or working fluid
sorbent that has absorbed the refrigerant in gains the solar energy and supplies it to the
the absorber. The refrigerant vapour adsorber. So the cooling capacity actually
generated in this process condenses in the depends on the amount of energy collected.
condenser rejecting the condensation heat Absorption refrigeration has been
Qc to ambient. The regenerated sorbent most frequently adopted for solar
from the generator is sent back to the refrigeration. It requires very low or no
absorber, where the sorbent absorbs the electric input and, for the same capacity, the
physical dimensions of an absorption
machine are smaller than those for
adsorption machines due to the high heat

4. transfer coefficient of the absorbent. areas where the grid extension is difficult
Besides, the fluidity of the absorbent gives and not economical. Such system
greater flexibility in realizing a more incorporates a combination of one or several
compact and/or efficient machine. renewable energy sources such as solar
photovoltaic, wind energy, micro-hydro and
Adsorption refrigeration can be may be conventional generators for backup.
safely used as a normal refrigerator, water Photovoltaic directly convert solar radiation
chiller, ice maker etc. With necessary into electricity with peak efficiency in the
structural modifications, an air conditioner range of 9–12%, depending on specific solar
can also be designed on the same principles. cell type. More than 80% of the solar
Many prototypes are already available in radiation falling on photovoltaic cells is not
laboratory scale and are successfully converted to electricity, but either reflected
operated. Though they may not be as or converted to thermal energy. This leads to
powerful as vapor compressor counter parts an increase in the PV cell’s working
and their COPs are less compared to the temperature and consequently, a drop of
latter, their major advantage lies in the fact electricity conversion efficiency.
that they don’t use any or in some cases very
less(10-50W) of electricity. So homes can
be cooled in summer without any excess
electricity bills.
A prototype water chiller based on
adsorption and heat pipes is shown below.
This can be successfully implemented as a
water chiller providing chilled water at 14-
17C.
In view of this, hybrid photovoltaic
and thermal (PV/T) systems are introduced
to simultaneously generate electricity and
thermal power. Hybrid PV/T is a
combination panel that converts solar energy
into both electrical and thermal energy. In
2.3 HYBRID PV/T system applications the production of
PHOTOVOLTAIC/THERMAL (PV/T) electricity is the main priority, therefore it is
SYSTEMS necessary to operate the PV modules at low
temperature, the carrier of thermal energy
Hybrid energy system is an excellent associated with the PV module may be
solution for electrification of remote rural either air or water.

5. A hybrid PV/T has many heat pump (PV-SAHP) is shown in the
applications apart from electricity figure below. A PV-SAHP is mainly
generation. They include water and space composed of four major components: PV
heating, agricultural crop drying and green evaporator, variable-frequency compressor,
houses. water-cooled condenser, and electronic
If a PV/T collector is directly expansion valve.Apart from supplementing
coupled to a solar heat pump, better cooling the compressor of the heat pump through
effect can be achieved. Such a compound thermal energy, this system drives its own
system is named a photovoltaic solar compressor from PV panels, thus
assisted heat pump (PV-SAHP). In this eliminating the need for external supply.
arrangement, the PV/T collector also serves For increasing the efficiency of solar
as the evaporator of a Rankine refrigeration photo-voltaic system, we can design a
system and is therefore called a ‘‘PV simple photovoltaic tracking system. The
evaporator”. While some of the solar energy designed PV solar tracking system offers
(the shortwave portion) received at the PV low wind resistance compared to other
evaporator is directly converted to designs and it is an efficient energy-
electricity, most of the energy is absorbed by conversion system. It may be used in rural
the refrigerant as latent heat and the and remote areas as a power source for low-
remaining portion is lost to the ambient. The power applications such as cathodic
evaporator cooling effect lowers the solar protection systems and domestic power
cell working temperature and improves the requirements. Cost analysis of the proposed
photovoltaic efficiency. At the same time, PV solar tracking system shows that it is
the evaporator pressure and temperature are either cheaper or at least comparable to any
elevated because of the solar absorption, and other power generation system for low-
consequently the COP of the system is power applications.
increased.
A hybrid photo voltaic solar assisted

6. 3. CONCLUSION REFERENCES
1) Solar refrigeration options – a state-of-the-art
A comprehensive study for the review
implementation of solar technologies has D.S. Kima, C.A. Infante Ferreirab, Arsenal Research,
been done. Some of the technologies are Sustainable Energy Systems, Giefinggasse 2, 1210
mature while some are still nascent. Vienna, Austria .Delft University of Technology,
Nevertheless, solar energy –a low heat Engineering Thermodynamics, Leeghwaterstraat 44,
2628 CA Delft, The Netherlands.
source- has a huge potential in small scale International journal of refrigeration (2008)
applications. A brief summary of the study 2) Efficient adsorption refrigerators integrated
is presented in the next few lines. with heat pipes
R.Z. Wang, Institute of Refrigeration and
1) Sorption Air Conditioning and Cryogenics, School of Mechanical Engineering,
Shanghai Jiao Tong University, Shanghai 200030,
Refrigeration which utilizes solar energy China.
(in the form of hot water) can resolve the Applied Thermal Engineering (2008)
refrigeration and AC needs of a home with 3) Performance evaluation of a hybrid
no or very little electricity. photovoltaic thermal (PV/T) system
A.S. Joshi a,b,1, A. Tiwari , G.N. Tiwari , I. Dincer ,
B.V. Reddy. Centre for Energy Studies, Indian
2) Solar Photo Voltaic can supplement the Institute of Technology-Delhi, Hauz Khas, New
electricity demand of house but may not be Delhi 110016, India.
efficient. A Hybrid Photo Voltaic/Thermal Faculty of Engineering and Applied Science,
(PV/T) not only produces electricity, but University of Ontario Institute of Technology
also doubles up as a thermal collector (UOIT), Oshawa, Ontario, Canada L1H 7K4.
4) Performance analysis of a photovoltaic heat
thereby increasing the overall efficiency and pump
reducing the energy payback period. Ji Jie a,*, Liu Keliang a, Chow Tin-tai b, Pei Gang a,
As we observe carefully, it is He Wei a, He Hanfeng a
obvious that utilization of solar energy a Department of Thermal Science and Energy
mostly depends on how efficiently we Engineering, University of Science and Technology
of China,Jinzhai Road 96#, Hefei City, People’s
harness solar radiation. It involves Republic of China
implantation of efficient collectors with low b Division of Building Science and Technology, City
radiation losses. Also selection of collectors University of Hong Kong, Tat Chee Avenue,
depends on load requirements and economic Kowloon,Hong Kong SAR, People’s Republic of
factors. The larger the loads, the more China.
6) Performance analysis of photovoltaic systems:
efficient the collector should be as operating A review
temperatures are high. The more efficient Anand S. Joshi, Ibrahim Dincer *, Bale V. Reddy.
the collector, the more expensive it is. So a Faculty of Engineering and Applied Science,
careful study is quintessential before University of Ontario Institute of Technology, 2000
implementing any of these solar techniques. Simcoe Street North, Oshawa, ON L1H 7K4, Canada
Renewable and Sustainable Energy Reviews.