International Journal of Engineering Trends and Technology (IJETT) - Volume4Issue4- April 2013
A Critical Review on Air Conditioning for
Energy Conservation and Application
Dr. U. V.Kongrea ,A.D.Rajeb ,A.L.Anantwarc ,A.B.Kaled
a
Asso. Prof. Mechanical Engineering Department, J.D.I.E.T Yavatmal (M.S), India.
b,c,d
Final Year Mechanical Engineering Department, J.D.I.E.T Yavatmal (M.S), India.
conditioning and heat recovery ventilation are
the by-products. As a matter of fact, a higher
condensing temperature is difficult to obtain by
using different refrigerants [2]. The use of Heat
Pumps for the heating and cooling of the
Equitable Building , was a pioneering
achievement in the Western hemisphere[3].
Many technologies are developed for heat pump
so that it can be used for various purposes. Ito
and Miura [4] investigated the mechanism of
Heat pump for hot water supply using dual heat
sources such as ambient air and water then, the
performance of a Heat pump, which used water
and the ambient air as the heat sources to heat
water, was experimentally studied. Along with
heat pump there is also development in the field
of air-conditioning. Ji. et al. [2] introduced a
novel air-conditioning product, that could
achieve the multi-functions with improved
energy performance. They reported the basic
design principles and the laboratory test results.
The results shows if a water heater is
incorporated in the outdoor unit of a split-type
air-conditioner, so that space cooling and water
heating could take place simultaneously, also the
energy
performance
could
be
raised
considerably.
Abstract- The technology of using a heat pump for a
space conditioning and domestic hot water heating in
residences has been developed for half a century. The
earlier air to water heat pump and water heating heat
pump gives only hot water and space conditioning
and suffered from drawbacks like high cost,
unreliable operation and inflexible application. But in
this air conditioner cum water dispenser we get hot
and cold water with hot and cold air. Thus it becomes
multifunctional easily. This paper presents a review
of a heat pump as well as a novel air-conditioning
product that can achieve the multifunctions with
improved energy performance. It obviously
improving the efficiency of residential air
conditioning units would decrease utility bills and
pollution produced by the power generation.
Keywords: heat pump, space conditioning,
water dispenser, etc.
I.
INTRODUCTION-
Heat pumps were first used by peoples
in 1950s for space heating and for domestic hot
water heating. They were not reliable and
expensive and the maintenance cost was high.
The earlier air to water heat pump and water
heating heat pump suffered from drawbacks like
high cost, unreliable operation and inflexible
application. Most residential water heaters are
equipped with conventional heaters generating
heat by consuming fossil fuels or electricity.
Those water heaters are usually simple, but not
desirable in view of energy utilization &
efficiency. These early models were suffered
from high purchase prices, high maintenance
costs, noisy, poor, longevity a limited installation
options. For instance, Energy saving is one of the
key issues not only from the view of energy
conservation but also for the support for global
environment [1]. After 1950s there is effective
development in the field of heat pump. Heat
pump water heater is a promising technology and
use mechanical principles of refrigerators and air
conditioners. The technology of heat pump has
been used for waste heat recovery and hot water
production. Water heating is the main task of the
heat pump water heater; the additional air-
ISSN: 2231-5381
II.
BRIEF HISTORY OF VCR SYSTEM ADVANCES
Firstly there is an improvement in
single stage cycle of vapor compression
refrigeration. In single stage cycle of vapor
compression refrigeration the expansion in most
practical real vapor compression cycles
occurring in an expansion valve. It is an
irreversible throttling process. This causes a
reduced cooling capacity and an increase work
[6].
Hopper and Ambrose (1972) have
recommended an improved expansion process
with a replacement of the expansion valve by a
vortex tube [5]. Based on the principle of the
temperature splitting phenomenon of a Ranque
Hilsch vortex tube in which a stream of gas
divides itself into a hot and cold flow, (as a
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International Journal of Engineering Trends and Technology (IJETT) - Volume4Issue4- April 2013
natural heat pump mechanism) By this, the liquid
refrigerant is throttled to the evaporator pressure
while the vapor refrigerant is separated with hot
and cold flows. The cold vapor along with the
liquid is lead to the evaporator while the hot
vapor continues rejecting its heat before reaching
the evaporator. This leads to a lower quality of
refrigerant, by testing the cycle with various
refrigerants and showed different improved
performances [6]. Ahlborm et al. (1998)
produced a theoretical analysis explaining the
establishment of a secondary circulation in the
vortex tube. They demonstrated that a vortex
tube satisfies different required processes
employed in heat pumps [7].
By application of these various
processes on heat pump for increasing its
coefficient of performance. Another option for
COP improvement is the use of an ejector as an
expansion valve in the vapor compression cycle.
Domanski (1995) studied the ejector expansion
cycle with 38 different refrigerants and found
improvements in both the reduced work and
increased capacity. He also showed that the COP
improvement of the ejector expansion cycle is
sensitive to the ejector’s efficiency [8]. Menegay
and Kornhauser (1996) further increase the COP
up to 9% for a heat pump by the use of R12 by
modifying the ejector’s configuration with the
addition of a bubble flow tube fitted upstream of
the motive nozzle [9]. Further benefits such as
reduced pressure ratio and discharge temperature
etc. have also been seen in the ejector expansion
cycle (Disawas and Wongwises, 2005).
VCR compression system for heat
pump to increase its COP is then modified by
using compressor in place of ejector. Driver and
Davidson (1996) developed a unique positive
displacement compressor applied to the heat
pump and found a performance improvement of
over 25% for R134a compared with the cycle
using the conventional expansion devices. They
also showed that the higher the compressor
efficiency, the higher the potential performance
improvement [10]. Tamura et al. (1997) tested a
high temperature heat pump with a screw
compressor and expander separately, while
Henderson et al. (2000) used a rotary vane
compressor by the replacement for both the
expansion valve and the single compressor in a
heat pump [11]. Now there is large development
in the field of compressor to increase vapor
compression. Hewitt et al. (2006) recently
designed and evaluated an air-source heat pump
based on a scroll compressor operating with EVI
cycle for hot water production [12].
After all by using conventional energy
sources scientist and researchers had done
variations and modifications using non
ISSN: 2231-5381
conventional energy sources in heat pump at the
same period of time. A variable capacity directexpansion solar-assisted heat pump system was
developed and operated for direct hot water
application by Chaturvedi et al. [13]. The
proposed system employed a bare solar collector
which also acted as the system evaporator. A
solar-assisted heat pump dryer and water heater
were designed, fabricated and tested by
Hawlader et al. [14]. The performance of the
system had been investigated under the
meteorological conditions. The performance
indices considered to evaluate the performance
of the system included solar fraction (SF) and
COP with and without a water heater.
On the other hand there is development
in air conditioning system also. Various
modification and energy conservation is
discussed as follows
III.
ENERGY CONSERVATION OF AIR
CONDITIONER-
Energy is conserved from air
conditioner by using 3 ways such that
mechanical cooling, electromechanical cooling
and refrigerant development.
In 19th century, air conditioning by
using electricity and electromechanical cooling
was developed [15]. The first modern electrical
air conditioning unit was invented by Willis
Haviland Carrier in Buffalo, New York. Carrier's
invention controlled not only temperature but
also humidity. Carrier used his knowledge of the
heating of objects with steam and reversed the
process. Instead of sending air through hot coils,
he sent it through cold coils (ones filled with
cold water). The air blowing over the cold coils
cooled the air, and one could thereby control the
amount of moisture the colder air could hold. In
turn, the humidity in the room could be
controlled. Later, Carrier's technology was
applied to increase productivity in the workplace,
air conditioning came to be used to improve
comfort in homes and automobiles as well [16].
In 1906, Stuart W. Cramer of Charlotte,
North Carolina was developing ways to add
moisture to the air. Cramer says the term "air
conditioning", analogue to "water conditioning",
He combined moisture with ventilation to
"condition" and change the air in the factories,
controlling the humidity so necessary in textile
plants [17].The evaporation of water in air, to
provide a cooling effect, is known as evaporative
cooling, was invented that time. Evaporative
cooling was the first real air-conditioning and
shortly thereafter the first private home air
conditioning was built in Chapel Hill, North
Carolina Dubose designed an ingenious network
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International Journal of Engineering Trends and Technology (IJETT) - Volume4Issue4- April 2013
of ducts and vents [18]. In 1945, Robert Sherman
of Lynn, invented the portable, in-window air
conditioner that cooled and heated, humidified
and dehumidified, and filtered the air [19].
Air conditioning by using refrigerant is then
developed.
The
first
air
conditioners
and refrigerators employed toxic or flammable
gases, such as ammonia, methyl chloride,
or propane, that could result in accidents when
they leaked. Thomas Midgley, Jr created the first
non-flammable, non-toxic chlorofluorocarbon
gas, Freon [20].Day by day various changes and
technology is
developed.
Various
air
conditioning units is created by various scientist.
Water heating and space heating models are
created by many researchers. Currently study is
on a novel air-conditioner that possesses multifunctions: space cooling, domestic hot water
heating and space heating [21].
When a heat pump is connected with an air
conditioning system and passing refrigerant
through condenser and evaporator resulting hot
and cold water, further recycles it through air
conditioner resulting hot and cold air also. Thus
it is possible to get hot air and hot water along
with cold air and cold water. Table 3.1 reviews
the research efforts taken by various researchers
combined air conditioner cum dispenser
separately.
Studies related to air & water cycle
Name of
scientist
Water
heating
Water
cooling
Space
heating
Space
cooling
Ranque Hilsch


Heat pump
(vortex tube)
Ahlborm


Establish
secondary
circulation in
vortex tube.
Hopper and
Ambrose


Heat pump
(expansion
valve)
Ejector
expansion valve
Apply
compressor to
HP
Domanski


Driver and
Davidson


Henderson


Apply rotary
vane
compressor to
HP
Ito and miura


Duel heat pump
Hasegawa et al


Two stage
compression
with cascade
heat pump
Ma et al


Economized
vapor injected
cycle
Menegay and
Kornhauser


Increase the cop
by modifying
the ejector’s
configuration
with the
addition of a
bubble flow
tube.

WillisHaviland
Carrier

Controlling of
temperature and
humidity
Zhang et al


Air source heat
pump water
heater
Hepbasli et al


Ground source
HP water heater
Ji.et al.




Novel air
conditioning
Swardt and
Mayer




Ground source
heat pump
coupled with air
conditioner
Hawalder et al


Solar assisted
heat pump water
heater
Hewitt et al


Air source heat
pump based on
scroll
compressor
Chaturvedi et al


A variable
capacity direct
expansion solar
assisted Heat
pump
Table- Study of reviews on Air
Conditioner & dispenser.
ISSN: 2231-5381
Experimental
study on
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International Journal of Engineering Trends and Technology (IJETT) - Volume4Issue4- April 2013
IV.
CONCLUSION
The technology of heat pump reduces
energy consumption, fuel cost and global
warming effect. By combining the airconditioning unit and the water dispenser into
one product, the air conditioner turns out to be
flexible, multi-functional, and economical.
Through the waste heat recovery process, the
overall Coefficient of performance of the device
can be much improved. It can work
independently as a domestic water heater and
water cooler also the heating efficiency and
cooling efficiency is much higher than that of the
electric water heater and water cooler. The
conventional air-conditioner only works in
summer. In most time of a year, it becomes idle.
The novel air-conditioner cum water dispenser is
suitable for use in any time of a year.
V.
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