Dmitry Chernyshev
T6614KA
Infrared heating as an alternative to
traditional heating systems in a singlefamily home in Russia
Bachelor’s Thesis
Building Services Engineering
May 2015
2
DISCRIPTION
Date of the bachelor's thesis
Author(s)
Double-degree program
Dmitry Chernyshev
Double Degree Programme in
Building Services Engineering
Name of the bachelor's thesis
Infrared heating as an alternative to traditional heating systems in a single-family home in
Russia
Abstract
In this thesis is examined a single-family home located in Russia. The main purpose of this
thesis is to find out the possibility of applying infrared heating as the main heating in
private homes.
The work consists of theoretical and practical parts. The theoretical part shows what it is
infrared technology and infrared heating, their classifications, classification another heating
systems.
The practical part consists of financial calculations which are necessary for
comparing the systems.
As a result of financial calculations the price of installing of the infrared electrical heating is
the cheapest , but the monthly costs for heating is the same like to use traditional heating
system.
Subject headings, (keywords)
Heating system, infrared heating, infrared foil, infrared panel
Pages
Language
27
English
URN
Remarks, notes on appendices
Tutor
Jarmo Tuunanen
Employer of the bachelor's thesis
3
CONTENTS
1.
INTRODUCTION ...................................................................................................4
2.
AIMS AND METHODS .........................................................................................5
3.
TYPES OF HEAT TRANSFER ..............................................................................6
4.
INFRARED TECHNOLOGY .................................................................................9
5.
INFRARED HEATING ..........................................................................................9
5.1 CLASSIFICATION OF INFRARED HEATER ...................................................10
5.1.1
GAS-FIRED INFRARED HEATERS ...............................................10
5.1.2
ELECTRIC INFRARED HEATERS .................................................13
6.
HEATING PROCESS COMPARISON ................................................................17
7.
ANALYSIS OF THE HUMAN CONDITION IN INFRARED RADIATION ....20
8.
INFRARED HEATING FOR SINGLE-FAMILY HOME ...................................22
9.
RESEARCH MODEL ...........................................................................................25
10. CONCLUSION .....................................................................................................28
REFERENCES ...........................................................................................................30
4
1.
INTRODUCTION
The issue of the choice of heating system has an important role in the construction of a
country house as well as choice of material of the walls and roof. As it is well known,
most of Russia is located in areas with temperate and cold climates. Therefore, the
heating season lasts on average 6-9 months, so heating costs take about 25-30% of all
supply energy. At the same time heat losses can run up to 30%./1./
Besides the traditional convection heating there are others. The most effective way of
heating is infrared.
Lack of sufficient information on the characteristics of the infrared heating systems; lack
of methods to determine the needs of thermal energy for such heating; lack of
engineering justification to find optimal variants locations of emitters do not allow for
widespread use of such systems.
5
2.
AIMS AND METHODS
The first of them is widening of the effective use of infrared heating systems of
residential premises to solve the problem of energy waste. The second aim is the study of
infrared heating effect on human and indoor climate. The third aim is to develop criteria
of comfort for the infrared heating.
In this work the following methods are used. The first method is analysis of the literature.
There are a lot of information about infrared heating system, so it is nessesary to take the
most accurate and reliable information.
The second method is to compare different way of heating system or, rather, their
features, values and characteristics. Each heating system has advantages and
disadvantages, which have a different influence on building, costs, indoor climate and
inhabitants.
The third method is measurement various characteristics in country house which is heated
using infrared heating system. Then to compare these characteristics with characteristic
provided by other heating system. Another method is technical and economic assessment
of an infrared heating system. This includes economic calculation of an ifrared heating
system in a single-family home.
6
3.
TYPES OF HEAT TRANSFER
Heat transfer is a process of transmission heat normally from a high temperature object to
a lower temperature object to achieve thermal balance. There are three basic ways of heat
transfer: conduction, convection and radiation.
“Conduction is heat transfer by means of molecular agitation within a material without
any motion of the material as a whole.” /2./ Schematic circuit of the way is given in
figure 1. In this figure we can see heat transfer from hot part to cold. The most thermally
conductive material is metal.
FIGURE 1. Heat conduction between two plane surfaces /2./
“Convection is heat transfer by mass motion of heat carrier as water when the heat
transfer medium is caused to move away from the source of heat, carrying energy with
it.” /2./ Illustration of the way is given in figure 2. In this figure the air is heated up by
radiator and goes up and then it cools down and goes down. It is so because warm air has
lower density than cool air. Thus there is temperature difference in a heated room by
convective ways.
FIGURE 2. Heat convection in a room /2./
7
“Thermal radiation is energy transfer by the emission of electromagnetic waves which
carry energy away from the emitting object.” /2./
Infrared radiation is thermal radiation. Thermal radiation is electromagnetic radiation.
Energy is created the thermal motion of atoms, molecules and other particles of matter.
Thermal radiation energy is energy moved by electromagnetic radiation obtained by
thermal excitation motion of the particles of matter. /2./
Thus any bodies which have temperature greater than absolute zero emit thermal
radiation. The most famous source of thermal radiation is the Sun. Hot plasma of the Sun
generates thermal radiation. The Earth absorbs the Sun’s radiation that determine the
temperature and climate of the Earth.
For talk about thermal radiation it is necessary to introduce such terminology as
absorptivity, reflectivity, and emissivity. The absorptivity is the ability of body’s surface
to absorb one or another spectral radiant power. The body which has perfect absorptivity
at all wavelengths is called black body. Reflectifity is the ability of bofy’s surface to
reflect one or another spectral radiant power. The body which has perfect reflectifity at all
wavelengths is called white body. Emissivity is the ability of body to emit energy as
thermal radiation with some effectiveness.
Emissive power is known as Stefan-Boltzmann law and it can be write by formula 1
which is valid for a black body:
𝑗 ∗ = 𝜎𝑇 4
(1)
where
𝑗 ∗ - the irradiance [W.m-2];
𝜎- Stefan–Boltzmann constant [W.m-2.K-4];
T- thermodynamic temperature [K].
Speaking of thermal radiation, it should be noted about the Wien Displacement law:
wavelength is inversely proportional to the temperature of the emitting light. The Wien
Displacement law is used with formula 1:
𝑏
𝜆𝑚 = 𝑇
where
(1)
8
𝜆𝑚 - maximum wavelength [m];
𝑏 = 2 ∙ 103 - Wien's displacement constant [𝑚 ∙ 𝐾] ;
𝑇 - radiation temperature [K].
9
4.
INFRARED TECHNOLOGY
Infrared radiation is electromagnetic radiation with the wavelength range around 0,75 µm
to 2000 µm. Infrared waves can be classified into five group:

Near-infrared (NIR) is in the wavelength around 0,75 µm to 1,4 µm.

Short-wavelength infrared (SWIR) is in the wavelength around 1,4 µm to 3 µm.

Mid-wavelength infrared (MWIR) is in the wavelength around 3 µm to 8 µm.

Long-wavelength infrared (LWIR) is in the wavelength around 8 µm to 15 µm.

Far-infrared (FIR) is in the wavelength around 15 µm to 1000 µm. p.12-13,/3./
FIGURE 3. Electromagnetic spectrum /4./
Classification of electromagnetic waves is shown in figure 3. These waves can be
classified into eight primary groups. Depending on the length of the radiated wave
heaters can be classified into three types: short-wave, which have length 0,77-15 micron;
medium-wave with length 15-100 micron; long-wave with length 100-420 micron.
5.
INFRARED HEATING
Infrared heating is heating system, where the infrared emitters are used as heat sources.
There are several types of construction of infrared emitters which work on different
energy sources such as gas, oil and electricity.
The main difference between infrared heaters from other types of heating is that thermal
radiation from the infrared heater is not absorbed and diffused air. All radiated energy
directly reaches the people and objects, than objects heat and transfer heat to the
surrounding air.
10
5.1 Classification of infrared heaters
In accordance with the Wien Displacement law infrared heaters with short-wave have
higher temperature than long-wave. Depending on surface temperature of the radiation
infrared emitter is devided: ”bright” high-temperature,which have temperature trad>1000
℃; ”bright” medium-temperature, where temeperature is 800<trad<1000 ℃; catalytic
low-temperature, where temperature is 600<trad<800 ℃; ”dark”, which has temperature
400<trad<600 ℃; ”subdark” have temperature 200<trad<400 ℃.
Independently of kind of energy source principle of operation of infrared heaters almost
the same. However, performance characteristics of each type of infrared heater is
different. Also to achieve a comfortable temperature and other characteristics of the
indoor climate, specific infrared heating system is needed for each concrete area (such as
industrial premises, warehouse, sales area or living quarters). /5./
5.1.1
Gas-fired infrared heaters
Nowadays gas-fired infrared heaters is used very often. Usually it is utilized for heating
of large spaces. Principle of operation of gas-fired infrared heaters consist in that these
heaters burn gas to heat a specific radiating surface. Then heated specific radiating
surface emits an infrared radiation with any wavelength. Only about 10 to 20% all energy
of combustion of gas is infrared radiant energy. The wavelength can be controlled by
desing of gas-fired infrared heaters.There are three types of gas-fired infrared heaters.
Indirect infrared radiation heaters
Indirect infrared radiation heaters consist of multitude elements. One of main elements is
radiating surface, usually it may be tubes or panels with metal or ceramic components.
Combustion occurs inside the heater. The radiating surface is heated to 1200 ℃. Indirect
infrared radiation heaters are usually vented and may have eductors. Construction of
indirect infrared radiation heaters is shown in figure 4.
11
FIGURE 4. Indirect tube-type infrared heater /6./
Heating process of the one consists of burning of gas, which heats radiant tube emitting
infrared heat. Reflector is needed to direct the heat down.
Porous-matrix infrared radiation heater
Porous-matrix infrared radiation heater also works with gas. The heater consists of the
major surface (the matrix) directed to the load and enclosing unit. The major surface has
the porous structure and may be porous ceramic, drilled port ceramic, stainless steel, or a
metallic screen. Gas is moved in the enclosure where combustion occurs equally on the
exposed surface, i.e. on the reverse side of matrix. In result the flame traverse the porous
surface, which adds radiant energy to the flame. Temperature of the surface is 900 to
1000℃. Construction of the porous-matrix infrared radiation heater is shown in figure 5.
FIGURE 5. Porous-matrix infrared radiation heater/6./
12
Catalytic oxidation infrared radiation heaters
Another type of gas-fired infrared heaters is catalytic oxidation infrared radiation heaters.
It differs from porous-matrix infrared radiation heaters only refractory material is usually
glass wool and the major surface is a catalyst which makes oxidation without visible
flames. Construction of catalytic oxidation infrared radiation heater is shown in figure 6.
FIGURE 6. Catalytic oxidation infrared radiation heater /6./
The next table shows some characteristics gas-fired Infrared heaters.
TABLE 1. Characteristics of Typical Gas-Fired Infrared Heaters /6./
Characteristics
Indirect
Porous Matrix
Catalytic Oxidation
Up to 650
900 to 1000
350 to 370
Low, up to 24
Medium, 55 to 104
Low, 2,5 to 9,8
180
60
300
0,35 to 0,55
0,35 to 0,60
-
Excellent
Excellent
Excellent
Vibration resistance
Excellent
Excellent
Excellent
Color blindness
Excellent
Very good
Excellent
Luminosity
To dull red
Yellow to red
None
Mounting height, m
2,8 to 15
3,7 to 15
to 3
Flexibility
Good
Excellent
Operating
temperature, °C
Relative heat flux,
kW/h.m2
Heat-up, s
Thermal radiationenergy input ratio
Thermal shock
resistance
Limited to low-heatflux applications
13
5.1.2 Oil-infrared heaters
Oil-infrared heaters have similar construction as indirect infrared radiation heaters. Also
oil-infrared heater is vented. They are used to heat large spaces with lack of electricity
consumption, premises with poor insulation and open areas.
5.1.3 Electric infrared heaters
Also electric infrared heaters are used as a heat source. Naturally heat produced in the
heater is created by electric current flowing in a high-resistance wire, graphite ribbon, or
film element. There are several type of electric infrared heaters.
Metal sheath infrared radiation elements
Metal sheath infrared radiation elements generally contain a nickel-chromium heating
wire which is in a metal tube. The metal tube can be heated to 1000 °C. Also there is
reflector on the unit which directs radiation to the load.
FIGURE 7. Metal sheath infrared radiation element/6./
Construction of metal sheath infrared radiation element is shown in figure 7. The wire
heated up by electricity gives heat steel alloy sheath, which emits infrared radiation.
Reflector lamp infrared radiation heater
Reflector lamp infrared radiation heater is made of a coiled tungsten filament, which is in
a clear, frosted, or red heat-resistant glass envelope. For good reflectivity interior surface
of glass is silver-plated. Construction of reflector lamp infrared radiation heater is shown
in figure 8.
14
FIGURE 8. Reflector lamp infrared radiation element /6./
Quartz tube infrared radiation heater
Quartz tube infrared radiation heater consists of a wire, which is in a tube. Wire is a
coiled nickel-chromium, and tube which is capped by porcelain or metal terminal blocks
is made of fused quartz. The heater is exposed impact and vibration, but it well
withstands shock thermal shock and splashing. The heater is mounted horizontally to
minimize coil sag. Construction of reflector lamp infrared radiation heater is shown in
figure 9.
FIGURE 9. Quartz tube element /6./
Tubular quartz lamp unit
Tubular quartz lamp unit is one more of infrared heaters, which has a fused quartz tube
and a coiled tungsten filament. There is inert gas in the tube. The filament is as straight
line by tantalum spacers, also both ends of the filament are implanted sealing material at
the ends of the envelope. It is necessary to set the heater up horizontally to prevent sag of
tube and overheating of the sealed ends. The filament is heated to 2200 °C, but surface
has lower temperature equals about 600 °C. Construction of tubular quartz lamp is shown
in figure 10. /6./
15
FIGURE 10. Tubular quartz lamp element /6./
Infrared foil heaters
Infrared foil heaters are one of popular infrared heater for country house. These heating
elements have a carbon heating conductor embedded in flat synthetic material. The
synthetic material serves as the substrate and insulating material. The foils are flexible,
because there are not solid materials. Maximum operating temperature is to 280 °C, and it
depends on used materials. /7./ Construction of infrared foil heater is shown in figure 11.
FIGURE 11. Infrared foil heater /7./
Commonly infrared foil consist of base film, copper foil booth bar, silver booth bar,
carbon, laminex film. Source of infrared heat is carbon, which is connected by electrical
booth bars.
TABLE 2. Characteristics of Electric Infrared Elements /6./
Characteristic
Resistor material
Metal
Reflector
Quartz Tube
Quartz Lamp
Foil heater
Sheath
Lamp
Nickel-
Tungsten
Nickel-
Tungsten wire
Carbon
chromium
wire
chromium alloy
16
alloy
Relative linear heat Medium, 60
flux
W/in.,
High, 125 to
Medium
375 W/spot
high, 75 W/in.,
0.5 in.
to High, 100 W/in.,
110-190 W/m2
3/8 in. diameter
0.5 in. diameter
diameter
950
2200
920
2200
to 280
850
280
650
600
to 280
Thermal radiation- 0.58
0.86
0.81
0.86
0.95
A few seconds
A few seconds
High (7.5 lm/W)
None
Resistor
temperature, °C
Envelope
temperature, °C
energy input
ratio
Response time
180 s
A
few 60 s
seconds
Luminosity
Very
low High
(8 Low (orange)
(dull red)
lm/W)
Excellent
Medium
Medium
Medium
Excellent
Impact resistance
Excellent
Medium
Poor
Poor
Poor
Mounting position
Any
Any
Horizontal
Horizontal
Any
Envelope material
Steel alloy
Regular
Vibration
resistance
or Translucent
heatresistant
quartz
glass
Clear, translucent, Polyester
or frost quartz
and integral red
filter glass
Color blindness
Very good
Fair
Flexibility
Good—wide Limited
Very good
to Excellent—
Fair
None
Limited—1 to 3 Good—wide
range of
125-250
wide range of W for each V;
range of
power
and 375 W power
1 length for each power density,
density,
at
density,
capacity
length,
120 V
diameter,
and
and voltage
length, and
practical
practical
voltage
length,
voltage
practical
Life expectancy
Over 5000 h
5000 h
5000 h
5000 h
10-20 years
17
Thermal radiation-energy input ratio is proportional of amount of spend energy to useful
thermal energy. In other words that is degree of efficiency. Response time is time that is
needed for achievement operating temperature. Luminosity is amount of light emitted by
a source of light per some area, name of unit is lumen per watt. Color blindness is ability
to shine.
6.
HEATING PROCESS COMPARISON
Every building have a heat loss. The heat losses are largely dependent on building
envelope. Even the building envelope is very effective, temperature of the space changes
depending on outside temperature.
All heating systems may be divided into tradional heating system, forced-air heating and
electric direct heating. In traditional heating system heat carrier is liquid, which is heated
and then it gives off heat spaces by passing through system of pipes and radiators. In
forced-air heating system heat carrier is air and also it is heated and then heats spaces
itself. In electric direct heating there is no heat carrier, and electric energy are
transformed directly into heat by special equipment.
Traditional heating systems are usually all types of boiler plant, which work by means of
natural gas, oil (diesel oil, mazut and ect.), electricity, solid fuel. At present time natural
gas is the most optimal and economically sound type of fuel in Russia. However,
connection to gas network is expensive enough in country house. And oil is not
comfortable since it is needed delivery and storage. Also oil has different quality.
Because of location of boiler plant there are specific smells of fuel (especially using of
diesel oil) and of combustion materials in house. Also there is risk of leakage fuel,
and removal of leakage is not very cheap. As a result of leakage fuel may damage
furniture, interior, structure of building, and also it is very harmful by inhalation. Periodic
work of boiler plant and pump can cause unnecessary noise and vibration. Also
preventive maintenance of boiler plant is needed for long and reliable operation. During
operation efficiency of the heating system decreases: boiler plant, flue and burner get
covered soot. As well heat carrier flows out partly and evaporates partly, and then gases
get to system and create airlocks.
18
Microflora of air perishes during operation of radiators with high operating temperature
(60-70 °C), i.e. “necrosis” air occurs. As well occurring convection currents create
draughts, which lift dust and distribute it in whole room. And there is temperature
difference (cold floor- hot ceiling), which is not very comfortable and useful for human.
Plus of the traditional system is a cheap price of fuel. Construction of boiler plant is
shown in figure 12.
FIGURE 12. Boiler plant /10./
Mainly boiler plant consists of burner and boiler. Water in burner is heated for heating
passing through boiler. In boiler hot domestic water is prepared by passing water for
heating. Such boiler is called indirect heating boiler. Expansion tanks are needed for
excess water which increases in volume when the temperature rises. Circulation pumps
direct water to consumer or to equipment.
Installation of electric direct heating is cheaper than the previous system has. From the
viewpoint of exploitation, if one something in electric heating is broken all the system
will work anyway, and replacement of broken equipment is very simply. Also especially
this kind of heating is easy integrated in control system of «smart» house.
There are two types of electric direct heating: convectional and emitting.
19
Electric convectors can be with natural air flow and with forced air flow. Natural air flow
convectors are like radiators with the exception of that convector can operate
independently. So problem of natural air flow convectors is the same as radiators
(“necrosis” air, convective flow, large thermal gradient in height space, not very
economy). Natural air flow convector is shown in figure 13.
FIGURE 13. Natural air flow convector /10./
Electric convectors with forced air flow are inapplicable for living rooms, because it have
high noise level, high airflow, large power consumption. Usually they are applied in
industrial departments.
Another type electric heater is infrared radiant heater. As already mentioned, there are a
lot of types of infrared heaters, but they have common advantages. Infrared heater heats
object directly without heat carrier. So due to that performance factor is higher (about
100%), than others. Heating rate of infrare heating is swifter about a few seconds to a few
minutes. It is possible to create zonal heating by infrared heater by means of diretion
radiation in some way. Setting of the system do not require large spending, and setting is
not very difficult relatively. Heating occurs evenly by the system; temperature is about 3
°C higher, than at ceiling, that is comfortable for human. /8./
20
7.
ANALYSIS OF THE HUMAN CONDITION IN INFRARED RADIATION
Not all types of infrared emitter can be used for heating of premises, especially living
room, because of being of possible negative effect of infrared radiation. When infrared
radiation falls on human skin, it partly is absorbed, partly reflected, and partly goes
deeper in body. Impact of infrared radiation depends on what part of heat is reflected and
depends on depth of warming of skin, it is shown in figure14, where Y-axis is percent of
absorption or reflection. Degree of impact of infrared radiation depends on wave-length
𝜆.
FIGURE 14. Impact of infrared radiation on skin /5./
Characteristic of skin: 1- reflective ability, 2- absorptance; I- ultra-violet radiation, IIvisible radiation, III- infrared radiation.
Human skin good reflects heat flow with wave-length 𝜆 < 0,7 µm, like about wavelength of sun. Reflective ability slumps if wave-length is increased to 1,8 µm. Therefore
sizeable part of heat flow is absorbed by skin, which is heated. Reflective ability is about
4-6 % if wave-length is 𝜆 = 2,0 − 2,6 µm. Warm skin depth also depend on wavelength, it is shown in figure 15. The higher temperature of the infrared emitter, the greater
21
the admittance of skin and the deeper skin warming of skin, which is undesirable for
human health.
FIGURE 15. Penetrability of infrared radiation /5./
1 - wave-length 𝜆 = 1 µm, 2 - wave-length 𝜆 = 1,4 µm, 3 - wave-length 𝜆 = 6 µm.
Another vulnerable region is eyes. As a skin, eyes does not have born protection against
infrared radiation, unlike sun infrared radiation. The most dangerous infrared radiation
for eyes is short-wave infrared radiation with length 1,0-1,8 µm. Such radiation can
produce different sicknesses of eyes, e.g. cataract. According the Wien Displacement
law, waves with lenth 1,0-1,8 µm is emitted by infrared emitter with 1300-2600 °C, so
use of such emitters is undesirable. Infrared emitters with 800-1200 °C emit waves with
length 2,0-2,6 µm is the most safe for eyes.
Thus for heating of space with the constant presence of people it is recommended to use
infrared emitters, which have temperature is less 1200 and waves 𝜆 = 2,0 µm. /5./
22
8.
INFRARED HEATING FOR SINGLE-FAMILY HOME
For correct choice of type of infrared heating it is necessary to select important
characteristics such as temperature of emitter, height of placing, performance factor.
Most suitable equipment of all types of infrared heating is electrical infrared heating for
country house, since them performance factor is most hight and not always there are
available gas in country house. It is shown in figure 16.
FIGURE 16. Radiant ceiling panel in a country house
«Radiant ceiling panels give out their energy as heat radiation, which spreads out on a
limited area. This allows accurate targeting of heating power. Ceiling panels are
especially suitable in applications, where it is necessary to heat a target without warming
up the surrounding air.
The ceiling or wall mounted heating panels can be divided in three groups according to
their surface temperature: in low and medium energy panels, the energy is transferred
from heating resistors into a panel, from which it spreads out into the room. The open
infrared heaters have got no protective panel, but the heat radiation from the resistors is
reflected downward into the room by a concave reflector.
Ceiling heating is controlled with a room thermostat that measures the air temperature in
the room. If also floor heating is used, the best result is achieved with a combination
thermostat, which measures also the floor temperature. »/9./ Example of room thermostat
is shown in figure 17.
23
FIGURE 17. Room thermostat
Also they can be mounted on the wall, in form of picture or even mirror, what is very
good solution for room interior.
Panels can have different power (200-6000 W). They are chosen according to heating
consumption of space. Ceiling height is important when selecting of panel power. In
order to protect yourself from burns high power panel may be used only when high
ceiling
and vice versa. In this way, panels are chosen according to space heating
consumtion and ceiling height. If ceiling is low, but space is large therefore heating
consumption is large as well, we install a lot of low power panels.
Another type of infrared heating which is used in country house is infrared heating foil.
The heating element heating foil is a thin metallic foil that is tightly laminated between
two plastic foils. There are fixing areas between the resistive modules and at both sides of
the foil. The thickness of the foil is less 1 mm. In spite of this the foil is highly durable
heating element.
The foil can be mounted at any place of the space. If the foil used like main heating, the
foil is mounted at ceiling. Also it can be used like underfloor heating for additional
heating. After installation of the foils they is covered by decorative material. Temperature
of the foils is less 50 °C.
24
FIGURE 18. Example of infrared heating foil
Infrared heating foils have many advantages than other heating equipment:
-
very simple installation;
-
the ability to easily dismantle the system, for example;
-
the highest rate of thermal comfort due to a temperature uniformity;
-
does not burn oxygen and does not affect the humidity in the room;
-
there is not intense convection which circulates dust particles;
-
triple savings when used as an additional source of heat.
Power consumption of heating foils is about 110-190 watts per 1 m². The most effective
method of installation is on ceiling, because of this the heat ray go downward in the
direction opposite to the movement in ascending air flows convection. /10./
25
9.
RESEARCH MODEL
Research model is one-room house. The walls of house are made of wood. It is located in
Saint-Petersburg and it is used as exhibition sample. It is shown in figure 19.
FIGURE 19. Research model
In the house there is infrared heating system as infrared heating foils. There is no other
heating system. In home the foils are invisible, also they do not take place, so more space
in the room.
FIGURE 19. Research model (inner space)
10.
MEASUREMENTS
Area of the house is about 10 m2. Inner space temperature is 19°C, and outside
temperature is -7 °C. There are six infrared heating foils on the ceiling covered with
wooden planks. They are shown in figure 20 and 21, which were made by thermal
imager. The foil have following parameters: power is 145 W, loading is 150 W/m2,
measures is 60x160.
26
FIGURE 20. Infrared image of the foil, which is under the covering, case 1
FIGURE 21. Infrared image of the foil, which is under the covering, case 2
The figures 20 and 21 show infrared heating foils. There is local temperature rise under
foils, but around temperature is lower, so foils have bright colour and other places have
blue colour.
FIGURE 22. Infrared image of the space at the middle level
27
In figure 22 we can see that the average temperature of wall is 18 °C, the highest is 21 °C
and the lowest is 15,6. The lowest temperature is between logs, where there are leakage
air.
FIGURE 23. Infrared image of the space at the high level
In figure 23 we can see that the average temperature of wall is 19 °C, the highest is 24 °C
and the lowest is 16,8. The lowest temperature is between ceiling and wall, where there
are leakage air too.
FIGURE 24. Infrared image of the space at the low level
As can be seen from the figures average surface temperature is 18 °C. Temperature of
the foils is about 50°C. The surface temperature of the floor is 18,7 °C. Thus, temperature
of the surfaces is different enough. It varies from 10,2 to 28,1°C. However the floor
temperature is 18,7 °C, that is high enough. Because of the surfaces give off heat
obtained from infrared heating foils, temperature of the space achieves about 19°C, which
is comfortable for human. Elecricity consumption:
28
W = P·t·T
(2)
where
W- elecricity consumption, kWh
P-power of the infrared foils, W
t- number of working hours
T- number of days.
P=p·n
(3)
where
p- power of the infrared foil, W
n- number of the infrared foils.
TABLE 3. Result of calculation
P, W
W, kWh
Cost, rub/month
870
209
366
Average prise for 1 kWh is about 1,75 rub/ kWh for country house in 2015.
In this way,heating costs for house with an area 10 m2 is about 400 rubles≈7euros. Thus
heating costs for average house is from 2000 to 4000 rubles, it depends on the thermal
protection. To economize insulation can be improved. If it is compared with gas costs is
the same, but gas pipeline are not everywhere,and connection to them is expensive.
11. CONCLUSION
Today people have developed how to use infrared technology in different spheres of life:
from science to even using in everyday life. One of them is heating spaces.
In this work it has been compared infrared heating and another different heating ways.
Unlike other methods of heating the infrared way has distinctive characteristics, that
beneficial affect the indoor climate and also human. However this is provided when there
are such conditions as the height of space, area of space, enough insulation.
It is discovered that not always existing types of infrared heating is suitable for the living
space. The most comfortable infrared light is sun infrared light with a range of waves 2,02,6 µm. The range of wave is emitted by such types of infrared heaters as infared heating
panels and infrared heating foils working on base of electricity.
29
They have distinctive advantages such as:
 infrared heating does not burn oxygen;
 does not dry the air;
 does not create drafts and dust circulating around the room;
 easy installation;
 savings in capital costs compared to traditional convective heating;
 high efficiency:
 uniform temperature in height.
Also the infrared heating have disadvantage such as relatively long heating of premises: it
is about 3 hours when house is completely cold. But it is not problem, when people live
in house permanently. Otherwise the special remote control system is can be installed,
that turns on the heating system when signal go from smartphone.
The most optimum arrangement of infrared heating system is on on the ceiling. If the
infrared heating system is used as additional heating, for example warm floor, it can be
installed on the floor or even on the walls. In terms of economic use the infrared electrical
heating consumes electricity quite a lot.
Cost of 1 kWh of natural gas is 0,31 rub, and electricity for country house is 1,75 rub.
Comparing the costs for gas and electricity as heating, the cost of gas is much cheaper.
But installation of gas equipment is more expensive.
As a result of work the infrared electrical heating is adequate alternative to traditional
convective heating. Using such type of heating the indoor climate becomes more
comfortable and harmless for a human. In future evolution of the infrared technology
will let us to reach to cheaper infrared heating.
30
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