ICT for Smart and Energy-Efficient Buildings

DIMITAR KARASTOYANOV

Institute of Information and Communication Technologies,

Bulgarian Academy of Sciences,

Bl. 2, ac. G. Bonchev str., 1113 Sofia,

BULGARIA

Abstract: - The article examines the application of new technologies and ICT for the construction of intelligent

and energy-efficient buildings. The state of the housing stock in Bulgaria is presented. The idea of using solar

tiles both as a roof and as a photovoltaic source of electrical energy is substantiated. Other elements of the

smart home management system are also described. The construction of a thermal energy storage system using

phase change materials is given, as well as a thermometer for the blind, facilitating the life of visually impaired

people at home.

Key-Words: - ICT, solar roof tiles, renewable energy, smart home, phase change materials, energy efficiency,

thermometer for the blind.

Received: April 23, 2024. Revised: September 14, 2024. Accepted: October 15, 2024. Published: November 18, 2024.

1 Introduction

The European Intelligent Building Group (EIBG),

the Japan Institute of Intelligent Buildings (JIIB),

the Chinese standard GB/T50314–2000, and others

offer different definitions of intelligent buildings.

EIBG offers a performance-based definition. EIBG

considers smart buildings to be those designed to

provide their users with the most efficient

environment and for the building to use and manage

resources as efficiently as possible to minimize

appliance and installation costs. Service-based

definitions describe smart buildings in terms of the

services and/or quality provided by the buildings.

JIIB provides a service-based definition: a smart

building has the functions of communication, office

automation, and automation at the service of its

occupants and is convenient for smart activities. The

definition of smart buildings is described by directly

addressing the technologies and technology systems

that buildings must incorporate. GB/T50314–2000

offers a solution for smart buildings. It states that

intelligent buildings provide building automation,

office systems, and communication networks and

optimally integrate structures, systems, services, and

management, providing the building with high

efficiency, comfort, convenience, and safety for the

occupants, [1], [2], [3], [4], [5].

2 Residential Buildings in Bulgaria

According to data from the National Sociological

Institute, there are about 4,000,000 homes in

Bulgaria, with approximately 66% of them located

in cities. Depending on the type of construction, the

largest percentage are brick buildings (about 80%

with beams or reinforced concrete slab), followed

by adobe, stone, and reinforced concrete

construction. In the cities, the percentage of panel

and reinforced concrete buildings is the largest

(approximately 12%), the rest includes mainly low-

rise buildings. Predominant for the country and low-

rise dwellings are pitched roofs, using ceramic,

concrete, bituminous, or metal tiles for covering.

Once installed, roof tiles have no function other than

weather protection. With the advent of solar panels

as an alternative energy supply option, the question

arises of including the roof tiles and the entire roof

structure in an independent home power supply

system, reducing the costs of heating, air

conditioning, and other daily energy needs by

supplying "green" energy, [6], [7].

According to data from the Ministries of

Economy, Energy, and Tourism, the potential of

solar radiation on the territory of Bulgaria is

significant. The average annual duration of

insolation is about 2150 hours with annual total

radiation ranging from 1400 to 1600 kWH/m2 and

represents about 49% of the maximum possible

insolation. There are relative differences in the

intensity of sunshine by region, and in terms of

territory, Bulgaria can be divided into four sunny

zones: Central-East, North-East, South-East, and

South-West.

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According to data from the same sources, 77%

of the country's territory is occupied by the forest

fund and arable land, as well as by territories

protected by law such as nature reserves, military

bases, etc., from which it is assumed that about 3%

of the territory of the country can theoretically be

used for photovoltaic energy. This makes the option

of installing rooftop solar systems for home use

even more attractive.

3 Smart and Energy Efficient Homes

In recent years, more and more private properties

and residential buildings have acquired solar panels,

aiming at a more ecological way of life and

minimizing electricity costs (the average return on

investment is 7-8 years). The end user faces three

options for handling energy: The energy from the

photovoltaic installation is to be used entirely for

own use; Sale of part or all of the energy produced,

which in turn requires significant costs of

connecting to the electricity grid and a mixed option

where part of the energy is used and the rest is sold.

With the introduction of smart home technologies

and the "Internet of Things" concept, it becomes

possible to manage and distribute the energy

produced from renewable sources in the home, as

well as its storage through special batteries, [8].

Renewable energy systems capture solar energy

using photovoltaic cells; also known as photovoltaic

panels. The electricity generated by the photovoltaic

panels partially covers the on-site needs, and the

grid provides additional electricity if needed.

Typically, the load on the roof structure from the

photovoltaic plant is about 20 kg/m2, and the power

reaches up to 5 kW. Some buildings do not have the

possibility for this type of installation and their

implementation is technically impossible due to the

inability of the roof structure to withstand additional

load, inappropriate orientation of the building,

height limitations of the additional photovoltaic

structure, etc. [5].

The solar tiles provide a suitable solution to

these and other problems. Through their

configuration, the offered systems built with solar

tiles perfect the capture of solar energy and its

distribution in the electrical network, simultaneously

performing the function of a roof.

An innovative idea is the construction of a roof

system (solar tiles) for energy-efficient construction

and energy storage (Figure 1). Its adoption enables

efficient and reliable roof constructions, reducing

electricity costs and providing "green" energy, with

the possibility of integration into technological

"smart home" systems (SHS's) and building

management systems (BMS) as well as storage of

the harvested energy (Figure 2), [9].

Fig. 1: Solar tiles

Fig. 2: Schematic diagram of a smart home

It fits perfectly with the goals for zero harmful

emissions and zero external energy consumption by

2050, as well as buildings. It is also part of the

future smart energy grids, including diversification

of electrical energy sources.

In this way, some of the peaks in consumption

will be smoothed out by shifting to periods with less

network load. It reduces the need for more

expensive and polluting conventional power at times

of peak load or large imbalance. This leads to a

reduction in costs for the system and reduces CO2

emissions, which within the framework of the ETS

(European Emissions Trading Scheme) has not only

ecological but also economic significance. Losses

from network transmission are also reduced.

Possible benefits for the consumer are a reduction in

the cost of energy; for the provider, reducing costs

and improving network stability; for society, it

reduces environmental pollution, [5], [9].

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The innovativeness of the proposed solution consists

in the use of solar tiles (for example solar

photovoltaic tiles with a power of 80 W or more and

a large operating temperature range: from -40 to +85

degrees Celsius), through the creation of a complete

smart system for energy management, which will

not only record the energy produced, consumed or

given away by the household but will be able to

learn itself and make a decision based on the

machine learning concept and user habits about

whether it should store or give away the energy

produced. A similar product, which combines in

itself a set of solar tiles for the production of

electrical energy, and operational and control units,

managed remotely via the Internet using a self-

learning software system, can be classified as an

innovation, not only in Bulgaria but also at the

European level.

4 Additional Elements in The System

4.1 The Temperature Controller for Types

of Solar Collectors

The temperature controller for types of solar

collectors allows for achieving maximum efficiency

when using similar types of systems, focusing on:

- Optimization and quality of the collected data

during operational work of the solar collector,

- Predictability of processes, through the

implementation of intelligent algorithms based on

the weather forecast and collected data on external

temperature and cloudiness,

- Construction of intelligent control of the Smart IoT

type, which will allow the remote monitoring of the

system and its adjustment through an Internet

connection and user applications,

- Optimization of the heat exchange processes

between the solar collector and the expansion

vessel, based on developed additional algorithms for

control and modulation of the pump circulation

group of the system,

- Reducing the possibility of overheating or damage

to the solar collector in case of excessive sunlight,

- Development of a smart, self-learning algorithm

for controlling solar collectors based on their

geographic location and heating intensity.

4.2 The Controller for the Management of

Heating-Cooling

The controller for the management of heating-

cooling fluid systems is designed for the

management of heating and cooling systems with

fluid circulation. Based on the world's energy

reserves and current gas and resource crises, more

and more people are paying close attention to the

optimization of their heating and cooling systems,

trying to achieve better efficiency. In this regard, as

one of the most effective technologies used, systems

using the circulation of water or other fluids with a

moderate temperature, which is largely known as

the so-called water floor systems, are increasingly

gaining ground. These systems achieve their

efficiency by circulating a fluid with a moderate

temperature in the range of 10 – 30 degrees Celsius.

The possibilities for achieving maximum efficiency

in the use of such type of systems focus on the

following several aspects:

- Carrying out research and experiments to

determine the optimal temperature of the circulating

fluid to achieve maximum heating efficiency, with

minimum energy consumption,

- Creation of a thermostatic controller to manage the

circulation process (water temperature, circulation

speed, operating time), based on real-time

temperature and humidity readings,

- Creation of possibilities for simultaneous control

of several heating circuits, using separate wireless

sensors,

- Implementation of IoT (Internet of Things)

technology to allow the controller to be monitored

and controlled remotely through an Internet

connection and mobile applications,

- Development of a smart algorithm to control the

heating and cooling process, matching the

temperature and humidity in the room with those

outside and eliminating the formation of

condensation.

Heating buildings with solar energy

significantly reduces the use of non-renewable

energy sources and alleviates the degree of

environmental and air pollution. A so-called

"combined solar system" is a heating system that

supplies heat for domestic hot water and space

heating in a building using two energy sources -

solar energy and any other auxiliary heat source to

solve the problems of solar energy instability and

insufficient heat storage, [5], [10].

5 Thermal Energy Storage

Thermal energy storage systems can store heat or

cold to be used later under different conditions such

as temperature, location, or power. These systems

are divided into three types: sensible heat storage

systems (sensation heat), latent heat storage

systems, and thermo-chemical heat storage systems.

Thermal energy storage tanks used in heating and

air conditioning systems have become more

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widespread in recent years, with stratified tanks

gaining in popularity, [11].

Knowledge of the melting and freezing

characteristics of phase change materials, their

ability to undergo thermal cycling, and their

compatibility with building materials is essential for

evaluating the short- and long-term performance of

latent heat storage systems. A typical heat storage

system is a water storage vessel in which

encapsulated tubes (pipes) filled with phase change

material are installed (Figure 3), [12].

Phase-change materials (PCM) used for heat

storage are chemical substances that undergo a

solid-to-liquid transition at temperatures in the

desired heating and cooling range. During the

transition process, the material absorbs energy as it

goes from solid to liquid and releases energy as it

returns from liquid to solid. A typical example of

PCM is storage vessels with types of special

paraffin (Figure 4), [13].

Paraffin is a hydrocarbon belonging to the group

of organic PCMs. The advantages of using organic

PCMs for thermal energy storage are low degree of

supercooling, chemical and thermal stability, and

non-corrosive. The special paraffin used as PCM are

a mixture of mainly straight-chain n-alkanes CH3–

(CH2)–CH3. The temperature range for

the transition from solid to liquid phase and vice

versa is from 36-38 0C to 66-68 0C depending on the

type of paraffin.

Thermal sensors

Fig. 3: Structure of an accumulator vessel with PCM

Fig. 4: Vessel with PCM in a building heating

installation

6 Facilities for the Visually Impaired

People with visual impairments (not to be confused

with reduced vision in the elderly) usually have

heightened other senses - for example, a greater

sensitivity to touch. They can sense small bumps on

the flat surfaces of objects. This is what the Braille

alphabet is based on, where symbols are represented

by a combination of small dots. This possibility can

also be used in the construction of some household

appliances for people with visual impairments.

The patented tactile thermometer for the

visually impaired is a bimetallic spiral (2) attached

at one end (3) to a base (1). The other end (4) of the

spiral (2), as the temperature increases, with its tip

(5) successively raises the lower end (9) of the

buttons (8). When the temperature decreases, the

spiral (2) shrinks back, and the buttons (8) are

retracted into their sockets (6) by return springs (7).

A visually impaired user can find out the

temperature of an appliance by feeling how many of

the buttons (8) are raised by touching the top edge

(10) of the buttons (8). The tactile thermometer is

intended for installation on a boiler, stove, radiator,

etc., for the convenience of a blind user living in a

smart home (Figure 5), [14].

Fig. 5: Tactile thermometer for the blind

7 Conclusion

Smart homes with the application of ICT increase

the quality of life of residents, reduce building

maintenance costs, and provide additional services.

The installation of additional systems for the

production, storage, and distribution of electrical

and thermal energy provides further advantages of a

smart home. The presence in the home of

orientation and control devices designed for

disadvantaged people is another factor in expanding

the circle of users of such a home. All the elements

of a smart building with ICT technologies can also

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be applied to farm buildings, for example, to

premises for growing plants and animals in

agriculture, [15], [16], [17].

Acknowledgment:

The paper is supported by the Bulgarian National

Science Program “Intelligent Animal Husbandry”,

Grant Agreement No D01-62/18.03.2021.

References:

[1] Wong, J. K. W., Li, H. and Wang, S. W.

(2005) Intelligent building research: a review,

Automation in Construction, 14(1): 143–159.

[2] Wong, J., Li H., Wang, S., (2005), Intelligent

building research: a review, Automation in

Construction, (2005), 14, (1): 143–59

[3] Tehrani, S. S. M., Saffar-Avval, M., Kalhori,

S. B., Mansoori, Z., and Sharif, M. Hourly.,

Energy Analysis and Feasibility Study of

Employing a Thermocline TES System for an

Integrated CHP and DH Network, Energy

Convers. Manage., vol. 68, pp. 281-292,

2013.

[4] C. Wilson, T. Hargreaves, R. Hauxwell-

Baldwin, Benefits and risks of smart home

technologies, Energy Policy 103 (2017) 72–83

[5] Pellegrini P., Fernández R., Crop

intensification, land use, and on-farm energy-

use efficiency during the worldwide spread of

the green revolution., Proc. Natl. Acad. Sci.

USA, 2018, 115, 2335–2340

[6] Yosifova V., Petrov R., Haralampieva M.

Initial research for passive and energy

efficient building awareness in Bulgaria. 23rd

International Conference on Circuits,

Systems, Communications, and Computers

(CSCC 2019), MATEC Web Conf. 292 03004

(2019), 2019, ISSN:2261-236X, 1-4.

[7] Engineering Tool Box, Thermo-physical

Properties, accessed 2 July 2018, from

https://www.engineeringtoolbox.com/, 2018

[8] Petrov R., Information and communication

technologies for smart homes., PhD

Dissertation, 2022, Sofia, Bulgaria

[9] Yosifova, V, Chikurtev, D, Petrov, R.

Research and analysis of modern space

heating technologies and management for

industrial buildings. IOP Conference Series:

Materials Science and Engineering, 878, IOP,

Publishing Ltd., 2020, ISSN:1757-8981, DOI:

https://doi.org/10.1088/1757-

899X/878/1/012010

[10] Zhou Z., Zhang Z., Zuo J., Huang K., Zhang

L., Phase change materials for solar thermal

energy storage in residential buildings in cold

climate. Renew. Sustain. Energy Rev. 2015,

48, 692–703.

[11] N. Soares, J. J. Costa, A. R. Gaspar, P. Santos.

Review of passive PCM latent heat thermal

energy storage systems towards buildings’

energy efficiency, Energy and Buildings 59

(2013) 82–103.

[12] Haralampieva M., Petrov R., Yosifova V..

Sensible Thermal Energy Storage Systems

Used in Buildings. The International

Conference on Technics, Technologies and

Education ICTTE 2020, 2021, ISSN:ISSN

1314-8796, DOI: doi:

10.15547/artte.2021.01.006, 49-57

[13] Haralampieva M., Intelligent management of

thermal energy saving systems., PhD

Dissertation, 2022, Sofia, Bulgaria

[14] Karastoyanov D., Stoimenov N., Gyoshev S.,

Thermometer., Bulgarian patent No 67158,

Sept. 24th 2020

[15] Wang, N., Zhang, N. Q. and Wang, M. H.

(2006) ‘Review wireless sensors in agriculture

and the food industry: recent development and

future perspective’, Computers and

Electronics in Agriculture, 50: 1-14.

[16] Georgiev R., K. Peychev, A. Pavlov, K.

Trendafilov, G. Dineva, I. Binev. 2013. Study

of a zeolite-water experimental refrigeration

module intended for animal raising,

Agricultural science, and technology, (2013),

vol. 5, N1, 58-61.

[17] Peychev K., R. Georgiev, G. Dineva. 2015, A

study of opportunities of using solar energy

radiation for underfloor heating in pig-shed,

International Journal of Agricultural

Innovation and Research, IJAIR 3.5

(2015):1516-1519.

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Contribution of Individual Authors to the

Creation of a Scientific Article (Ghostwriting

Policy)

Dimitar Karastoyanov carried out the simulation,

the data collection, and the experiments.

Sources of Funding for Research Presented in a

Scientific Article or Scientific Article Itself

No funding was received for conducting this study.

Conflict of Interest

The authors have no conflicts of interest to declare.

Creative Commons Attribution License 4.0

(Attribution 4.0 International, CC BY 4.0)

This article is published under the terms of the

Creative Commons Attribution License 4.0

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