APPLICATION with errors of less than ±0.1 °C.

APPLICATION
OF SMART SENSORS TO REDUCE ENERGY USAGE IN AIR CONDITIONING

 

1.
ABSTRACT

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

 In this study, phones, wearable/portable
devices, detectors that detect temperature and human motion are integrated as
smart sensors to reduce the amount of energy used for air conditioning and
ventilation. Advanced Smart sensors get input feedback from mobile phones, smart
gadgets and portable devices placed on human body. The data obtained can be
used to adjust(increase or decrease) air conditioners and ventilation systems
in advanced to the occupants’ intentions. Outcomes indicate that the indoor
temperature can be controlled faultlessly with errors of less than ±0.1 °C.
Fast chill off can be obtained within 2 to 3 minutes to the optimized indoor
capacity after occupants enter a room. It’s likewise noted that within 2 hour
operation the total compressor yield or output of the smart air conditioner is 48.4%
less than that of the particular case using On-Off control. The advanced smart
air conditioner with wearable or portable gadgets could identify those human
temperature and activity during sleep to determine the sleeping state and
adjusting the sleeping function flexibly. The sleeping or rest function optimized
by the smart aeration and cooling system with wearable units could reduce the
energy usage up to 46.9% and keep the human health. The presented smart air
conditioner could accomplish a comfortable environment and achieve the goals of
energy conservation and environmental protection.

 

2.
DEVELOPMENT OF HEATING, VENTILATION AND AIR CONDITIONING TECHNOLOGY TO REDUCE
ENERGY CONSUMPTION.

 

 For a higher quality and comfortable present
day modern lifestyle, individuals depend around air conditioners (ACs) much
more than the past. In both developing and developed countries, ACs tends to increase
the occupancy ratio of building areas. This also leads to a fast and rapid
development in the energy consumption by Air conditioning systems. According to
static data, HVAC very nearly expended half of the energy in buildings and 20%
of the total national energy utilization. Therefore, it is vital to diminish
the energy consumption of Ai Conditioning systems in private residential as
well as commercial buildings. The methods of creating new energy-efficient
equipment, applying complex and unpredictable control strategies, using solar
energy as a new vital energy source, etc., are all being considered for saving
energy in ACs. Among them, applying control methodologies may be the more
economical and efficient strategy. The outcomes show that the energy consumption
of pumps can be minimized by using these control methods. A feedback controller
for ACs is designed and improves the energy efficiency of aeration and cooling
systems. Experimental outcomes show that this method can come with a better
coefficient of performance of the Air Conditioner and a comfortable indoor
environment even in very hot and humid uncomfortable weather. For multi-unit Air
Conditioners, a fuzzy logic control method is used to control the operational
number of compressors and fans to enhance energy proficiency. The past
researches of applying control methodologies on ACs are mainly based on the
difference of parameters and cause the reaction. This is one kind of passive
responses and may not be suitable for human comfort and health. The developing
history of Air Conditioners is connected to the efficiency, technology, human
comfort, and energy utilization. Air Conditions’ progress includes window type,
split type, fixed frequency, convertible frequency, and the recently presented
smart type. In the 1990s, to reduce noise and satisfy the users, window type
air conditioners were modified to the split type by moving the compressor
outside the occupancy area. Since 2000, the high oil price and the need for
energy conservation have forced the control of compressors to be changed and
improved from fixed frequency to convertible. The fixed frequency control of
compressors adopts full power as the On-Off output, and causes temperature
changes and waste of energy. However, by utilizing an electronic expansion
valve, the modified convertible frequency control can adjust the compressor
output and the flow rate of refrigerant according to the indoor thermal mass
for energy conservation. Since 2010, smart phones, tablets, personal computers,
and cloud computing and 4th generation (4G) communication in 2014 were
generally used and have resulted in an information revolution. By utilizing communication
technologies, the adjustment of air conditioners is not only a single feedback
of setting information. A smart air conditioning system can be combined with an
infrared sensor for human position sensing, meteorological webs for outdoor
weather information, wearable devices for human activity and intention
awareness. Henceforth, air conditioners are expected to alter the indoor
temperature efficiently considering human comfort and energy conservation.

 

 

 

3. MATHEMATICAL MODELLING OF
AIR CONDITIONING CONTROL AND ENRGY USAGE

 

This study centered on
smart control of air conditioners utilizing mobile phones and wearable gadgets
as smart sensors. It’s the most up to date trend in air conditioner development.
Before presenting the design, a mathematical model of air conditioning control
is derived from fundamental theorems. That would help to illustrate the
following concepts clearly and plainly. The basic operating principle of the
air conditioner (aeration and cooling system) is the vapor cycle introduced by thermodynamics.
The vapor cycle includes the following steps:

 (1) The saturated refrigerant is compressed to
a higher pressure vapor, also known as superheated vapor;

(2) eliminating heat from
the system by either circulating water or air and is condensed into saturated
liquid;

 (3) Undergoing an unexpected decrease in
pressure through the throttle and expansion process, and becoming a liquid and
vapor refrigerant mixture with lesser temperature and pressure;

 (4) Absorbing the heat of an enclosed space or
space by a circulating fan in the evaporator and expands into the saturated
vapor;

 (5) Vapor is routed back into the compressor
to complete cooling cycle by cycle.

The vapor cycle
incorporates compression, heat extraction, expansion, and heat absorption.

This process is accomplished by the
compressor, condenser, expansion valve and evaporator. The more explained operating
principles of the vapor cycle include the variation of temperature, pressure,
enthalpy and entropy. For a traditional window type air conditioner, these 4
devices were installed in an air conditioner to carry out the vapor cycle and
chill down the closed area. Almost been 90% of the traditional window type
airconditioners are replaced by the split type now. The compressor and
condenser of the split type air conditioner are integrated in the outdoor unit
to avoid the compressor noise. The expansion valve and evaporator are organized
as the indoor unit. One of the many advantages of split AC is the fact that it
produces less noise, and this feature has made it  the main trend of air conditioners for home
and business purposes.

 

                                                                                                                              

 

 

 4. SMART CONTROLLER DESIGN
BASED ON SMART SENSORS

Before the introduction of the smart
control, the On-Off and Inverter control are perfectly described in the
following two sub-sections. Both of them, compared with smart control,
represent the difference causing control. Then the smart sensors, including
portable phones, wearable gadget units and other sensors, are introduced. These
will be the key components to decide human intentions. Finally, the outline of
a smart controller based on smart sensors and gadgets is illustrated to show
the intention causing control.

4.1.
On-Off Control of the Fixed Frequency Air Conditioner

The meaning of fixed frequency is the
compressor of the AC works in the fixed rotation velocity. The association between
the rotation speed of motor and electrical frequency can be explained as:

Speed (rpm) =
(120*f) (1-d) p

f = the
electrical frequency

 p = is the magnetic poles of motor

d = is the
rotary slip difference (d = 0 under zero loading).

The
temperature inside is kept stable by operating the compressor to on and off
positions, when the motor works in the fixed rotation speed and the indoor air
conditioning load is less. This method of operating the Air Condition is also
mentioned as On-Off control.

In the
method of On-Off control, the fixed frequency air conditioner turns on the
compressor when the return air temperature is higher than the set one, and
turns it off when it’s the opposite. By doing this, the refrigerant would flow
through the condenser and evaporator for heat exchanging with the indoor and
outdoor air to keep the indoor temperature stable.

4.2.
Inverter Control of the Convertible Frequency Air Conditioner

 The main air conditioning product for energy
conservation is the convertible frequency Air conditioner. It maybe characterized
as the situation where the rotation speed of the motor could be adjusted or
changed according to our wish for regulating the refrigerant energy output by
changing the input electric power frequency

Comparing
the convertible frequency type with the fixed frequency could first rectify the
60 Hz electricity into the direct current type, and then by using pulse width
modulation , modulate the frequency of output electricity . As stated by the
feedback temperature difference, the AC could provide the air flow of stable
temperature to control the temperature of indoor space by adjusting the
refrigerator flow.

 

 

5.
SMART SENSORS

Smart
sensors, including smart versatile phones, wearable units and other sensors,
are introduced in the market now. They are the key components of smart control
for detecting the human’s intention and passing it on to the system. Mobile
phones would provide occupants’ information by incorporating to the GPS and
personal schedule for collecting the position and intentions of the person. The
air conditioner could cool down the indoor temperature fast before the
occupants enter.

The wearable
gadgets and their provisions are predicted to have a sudden increase in the
coming future. Gadgets that are wearable , such as watches or bracelets, may be
adopted for detecting the human sleeping state as the feedback signals of the
sleeping function. The accelerator could detect the acceleration between 10 and
10?6 g, the velocity between 10 and 1.67 ×10?9 m/s, and the displacement
between 10 and 2.78 ×10?13 m. It can collect human motion information and
feedback to the smart air conditioner for further control.

5.1.
Smart Control Based on Smart Sensors

counting the
examination of the fixed and convertible frequency control schemes, the
quantitative investigation of the smart control based on the smart sensors is the
fundamental focus in this paper. Smart control, in  view of the information collected by the use
of mobile phones and wearable gadgets, strengthens the connection with
occupants and carries out the intention causing control. It might incorporate the
following aspects: (1) Mobile telephones with GPS and individual timetables,
for recognizing the tenants’ position and intentions, could anticipate the
occupants’ intention of entering the enclosed area. At this minute, the compressor,
which is off in the usual situation, could turn on in the full power. Before
entering, the circling fan turns on at the highest speed, and the air deflector
swings for 10 min to enhance the air circulation. consequently, smart control
may enable the enclosed space could be chilled off quickly after the tenants
enters. (2) The arm ornament with the accelerator could detect the development
of tenant while sleeping. After the occupant falls into a deep sleep, the air
conditioner would increase the inside temperature lightly to avoid energy
consumption. The smart air conditioner could adjust the compressor output
actively according to the occupants’ active intention (going home) and passive
one (falling into a deep sleep) for the goals of human comfort and energy
conservation. The smart air conditioner includes the following devices:

 (1) Air conditioner with changable
refrigeration power;

 (2) Novel sensors capable of collaborating
with inhabitants;

(3) Communicating
units for cell phone and network.

Figure demonstrates
the controlling structure of smart air conditioner, including ventilation
system, temperature sensor, IR indicator, mobile phone and wearable gadgets. The
control structure of the smart aeration and cooling system in Figure utilizes a
multi-sensor framework to achieve smart control. The indoor infrared sensor can
distinguish peoples’ position and carry out the air flow direction control. Cell
phones with GPS and personal timetable can be utilised to detect the
inhabitants’ position and intention. Wearable units can be the bracelet with
the accelerator. It understands the movement of occupants while sleeping. After
the occupant fallings into a deep sleep, the smart air conditioner would uplift
the indoor temperature lightly to avoid energy utilization.

Figure- The
control plan of a smart ventilation system with Inverter control: different
from the fixed and convertible frequency air conditioner with difference
causing control, it’s an intention causing control that adjusts the compressor
output effectively based the occupants’ active intention (going home) and
passive one (falling in a deep sleep) for the goals of human comfort and energy
conservation.