American Journal of Applied Science and Technology
56
https://theusajournals.com/index.php/ajast
VOLUME
Vol.05 Issue02 2025
PAGE NO.
56-60
10.37547/ajast/Volume05Issue02-14
Application of modern technologies in the development
of energy-efficient technologies
Pardaev Z.E.
Docent, department “Power Engineering”, Karshi State Technical University, Karshi, Uzbekistan
Khuzhakulov S.M.
PhD, Docent, department “Power Engineering”, Karshi State Technical University, Karshi, Uzbekistan
Toshmamatov B.M.
Senior Lecturer, department “Power Engineering”, Karshi State Technical University, Karshi, Uzbekistan
Received:
24 December 2024;
Accepted:
26 January 2025;
Published:
28 February 2025
Abstract:
The article analyzes the heat supply systems of industrial production processes and the amount of various
emissions released into the atmosphere from them. The use of heat pump systems in industry is of great
importance, taking into account environmental protection regulations and fluctuating fuel prices. Studies on the
energy integration of industrial heat pumps have revealed that, due to the widespread use of high-temperature
heat pump systems (>90
℃
), there are several opportunities for heating capacities from 20 kW to 20 MW, especially
in the food, paper, metal, and chemical industries. The problems of transitioning to a heating system based on
renewable energy sources have been studied.
Keywords:
Production processes, secondary energy sources, energy efficiency, heat pump devices, CO2,
environmental protection.
Introduction:
Heat supply is widely used in industrial
production, including chemical plants, for disinfection,
distillation, drying, regeneration and other purposes.
Heat flows with temperatures from 60 °C to 140 °C are
required to meet the heat supply needs of the fertilizer,
pulp, paper, and food industries. Burning organic fuels
usually provides the heating process, which hinders
efforts to decarbonize this sector. On the other hand,
waste heat is a by-product of these facilities, as it is
generated in exothermic chemical reactions occurring
in industrial and chemical plants. Despite the amount
of residual energy, low-grade waste heat is usually
discharged into the environment, which increases the
energy consumption of the system for cooling. In this
regard, heat pumps can use the available waste heat at
low temperatures to improve and meet heating
requirements, while partially or completely replacing
fuel-fired boilers and minimizing environmental
impacts [1,2]. Unlike electric resistances, which convert
power into heat energy; a large part of the energy input
to a heat pump is waste heat, which simultaneously
reduces the cooling load and electricity imports.
METHODS
As part of the project, the authors conducted a
literature
review,
using
analytical
methods,
observation, and other traditional methods.
The potential for heat pump systems in industry is
significant, especially given the environmental
regulations and volatile fuel prices. According to the
International Energy Agency’s Net Zero by 2050: A
Roadmap for the Global Energy Sector report, heat
pumps could meet 15% of the process heating demand
of light industry by 2030, and this share could increase
to 30% by 2050 [3]. The use of high-temperature heat
pumps has been proposed to increase efficiency and
reduce emissions in various energy conversion systems
[3]. Indeed, the effective use of heat pump technology
could reduce CO2 emissions in district heating systems
by 35%. The improvement and dissemination of
knowledge on the state-of-the-art, performance, and
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American Journal of Applied Science and Technology (ISSN: 2771-2745)
future developments of high-temperature heat pumps
(HTHPs) has been the subject of various studies [3].
Collaboration has been carried out within the
framework of the IEA Heat Pump Technology (HT)
Cooperation Programme to promote the development
and implementation of the technology. Problems
related to the need for high-temperature heat transfer,
as well as the need for refrigerants with low global
warming potential (GWP), have been identified.
Attention has been paid to the improved reliability and
safety of existing compressor technologies for large
heating capacities (>1 MW) [1,2,3].
In studies on the energy integration of industrial heat
pumps, several possibilities have been identified for
large-scale use of high-temperature heat pump
systems (>90
℃
), especially in the food, paper, metal
and chemical industries, with heating capacities
ranging from 20 kW to 20 MW. Most cycles are single-
stage, differing in the type of compressor and the
refrigerant used (e.g. R245fa, R717, R744, R134a or
R1234ze(E)). Raising the temperature from 95 K to 40 K
requires performance factors of 2.4 to 5.8. However,
overly conservative assumptions and generalizations,
such as the temperature conditions of the heat
sources, lead to incorrect conclusions about future
electricity requirements and fixed costs. According to
the researchers, it is recommended to study suitable
waste heat sources at high temperatures to reduce the
temperature rise and consequently the electricity
costs.
RESULTS AND DISCUSSION
In addition, sustainable global warming will lead to
greater utilization of waste and environmental heat,
which will reduce costs. According to estimates, the
current annual waste heat in China will save 1.3 billion
tons of equivalent fuel (calculated based on the ratio of
recycled waste heat to total national energy
consumption), and the recovery of waste heat
equivalent to 1 ton of equivalent fuel can prevent the
release of 2.77 tons of carbon dioxide into the
environment, which would be of great significance in
the use of renewable energy and the reduction of CO2
emissions.
When CO2 emissions are reduced to zero, an energy
transition based on expanding sources of energy
demand and reducing costs is expected. At the same
time, four challenges need to be addressed to
transform the heat sector in the coming decade,
including measures to generate, supply, store and use
heat, as well as to achieve zero CO2 emissions. These
challenges include (1) shifting heat to electrification, (2)
utilizing decommissioned thermal power plants, (3)
meeting the demand for large-scale heat storage, and
(4) identifying the final “10%” savings (Figure 1). Taking
into account the above challenges, four approaches are
proposed to overcome the energy transition problem
and develop an incentive strategy.
Figure 1. Four challenges of switching to a heating system based on renewable energy
sources.
To achieve CO2 neutrality, electricity generated in
thermal power plants (TPPs) using fossil fuels should be
replaced by renewable electricity from solar
photovoltaics, wind power, etc. [4]. Heat supply based
on fossil fuels is provided by electricity generated in this
case from renewable or low-CO2 emission heat supply
systems, and in the future from renewable sources [5].
The efficiency of converting large amounts of electricity
into heat falls below 1 according to thermodynamic
laws, so the price of heat supply can never be lower
than the price of electricity. In addition, a large amount
of waste heat generated in industrial processes and
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American Journal of Applied Science and Technology (ISSN: 2771-2745)
ambient heat from nature has not yet been fully
utilized [6].
In this case, high-potential heat pumps for the use of
electricity and low-potential heat energy have an
effective effect on the electrification of heat supply
systems. The heat energy extracted from the low-
temperature heat source through mechanical or
thermal work is transferred to the high-temperature
heat receiver, thereby establishing a connection
between electricity and heat. In the cycle of the
electrically powered vapor compression heat pump in
Figure 2 the low-grade heat energy extracted from the
ambient heat or waste heat is increased, thereby
further expanding the scope of low-grade heat energy
utilization.
Figure 2. Schematic diagram of a vapor compression heat pump.
According to the results of the conducted research, it
was found that the user's energy consumption mainly
consists of 20% electricity, 50% heating and cooling,
and 30% fuel. Ideas that can store heat, cold, electricity
and fuel by the ratio of energy consumption provide
energy savings and significantly improve safety.
Thermal power plants can be converted into energy
centers that can store renewable energy in the form of
heating, cooling, electricity, and fuel. The energy
centers in Figure 2 allow the integration of electricity,
heating, cooling, and pipeline networks and the
delivery of energy types to the city, acting as a bridge
between the demand and supply sides.
In particular, when transmitted over long distances,
some of the renewable electricity is stored directly in
batteries or in high-temperature thermal storage based
on a Carnot accumulator and then transmitted to users
via the local grid. The Carnot accumulator uses heat
engines and turbines in thermal power plants and
offers large-scale storage of renewable energy,
although the output of electricity is only 50% of its
input.
Another part of the delivered renewable electricity is
used by heat pumps to provide heating and cooling in
a reverse cycle.
After being improved and scaled up, the thermal
energy is stored and then delivered via the heating and
cooling networks. In this process, the efficiency and
flexibility of the heating and cooling supply can be
further increased by thermal energy regulation
methods, which are expanded in the next section. The
remaining renewable electricity can be used to produce
compressed and stored hydrogen and methane, which
is delivered to users through a pipeline network or
hydrogen stations.
The control of the operation of energy hubs is based on
optimizing costs and efficiency and adjusting power
and capacity over time. As energy consumers and
suppliers, energy hubs participate in the coordinated
management of the energy market and the operation
of all three utility networks.
The widely discussed 1.5°C scenario in early 2020
requires a reduction of 500 Gt of CO2 emissions [7]. By
mid-2022, 100 Gt of this amount had been absorbed,
leaving 400 Gt remaining. Existing and planned power
plants, mainly solid fuel-fired, will produce
approximately 500 Gt of CO2 over their lifetime [7]. The
power generation capacity of existing and soon-to-be-
commissioned coal-fired power plants will thus fully
cover the remaining 1.5°C CO2 budget. The main
reason for this disproportionate impact is that most of
the existing power plants are still new. Of the 2000 GW
of global generation, 720 GW is from solid-fuel thermal
power plants that have been in operation for less than
10 years, and 630 GW is from thermal power plants
that have been in operation for up to 20 years [8].
This is one of the reasons why the International Energy
Agency’s recent special report on CO2
capture and
storage (CCS) in the Energy Technology Outlook states
that net zero cannot be achieved without CCS [1]. In
American Journal of Applied Science and Technology
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American Journal of Applied Science and Technology (ISSN: 2771-2745)
addition to the potential for decarbonization by
upgrading existing emission sources (e.g. relatively new
coal-fired thermal power plants), CCS ensures the
decarbonization of complex sources (heavy industry),
the production of low-carbon fuels, and the capture of
CO2 that has already been emitted from the
atmosphere.
The research focuses on the potential of CCS to
decarbonize existing infrastructure, which relies
heavily on the development and deployment of
practical and cost-effective post-combustion CO2
capture
technologies.
Currently,
expensive
technologies are a major barrier to the development of
decarbonization processes, but costs can be reduced.
For example, SaskPower, the operator of one of the
two large-scale CCS processes for coal-fired power
plants built and operated to date, estimates that
second-generation CO2 capture devices could reduce
costs by 67% [5].
The rapid development of such second-generation CO2
capture technologies is critical to preventing the lock-
in of more expensive first-generation technologies.
There are various ways to achieve this integration. For
example, the two large coal-fired CHP projects
implemented to date use different approaches with
different advantages and disadvantages [9]. Boundary
Dam uses steam from a direct coal-fired CHP plant,
while Petra Nova uses a separate gas-fired CHP unit to
provide recovered heat and additional power.
The Boundary Dam approach is a preferred option for
deep decarbonization, particularly in Asia, where 77%
of the world’s coal is consumed and where much of the
natural gas must be imported at high cost. Designing
CHP plants is an important step in preparing for this CCS
upgrade, but it faces uncertainty about the steam
conditions required for future CO2 capture processes.
However, although significant modifications to the
power cycle are required, there are various schemes
for retrofitting non-CAB plants with only modest
efficiency gains [10].
CONCLUSIONS
This work explores another retrofit approach using a
CO2 capture concept that uses only electrical energy as
an input, which limits or eliminates any integration with
steam cycles that would increase the complexity of the
retrofit design. The concept is derived from the Rotary
Adsorption Reactor Cluster (RARC), which uses heat
and vacuum pumps to regenerate the sorbent using a
combination of temperature and vacuum oscillations.
Competitive efficiencies can be achieved in coal-fired
power generation, but the concept is more effective for
processes that do not have low heat to regenerate the
sorbent, such as cement production. However, given
the urgency of the RARC to rapidly upgrade the
“megaproject” of the world’s largest co
al-fired power
plants, in this work, the operation of heat and vacuum
pumps was compared with the use of low-pressure
steam under these conditions.
REFERENCES
Xenia Kirschstein, Max Ohagen, Joscha Reber, Philip J.
Vardon, Nadja Bishara. Regeneration of shallow
borehole heat exchanger fields: A literature review.
Energy
&
Buildings
317
(2024)
114381.
https://doi.org/10.1016/j.enbuild.2024.114381
Daniel Florez-Orrego, Meire Ellen Ribeiro Domingos,
François
Mar´echal.
Techno-economic
and
environmental analysis of high temperature heat
pumps integration into industrial processes: the
ammonia plant and pulp mill cases. Sustainable Energy
Technologies and Assessments 60 (2023) 103560.
https://doi.org/10.1016/j.seta.2023.103560
IEA, Industrial energy-related systems and technologies
Annex 13, IEA Heat Pump Program Annex 35,
Application of Industrial Heat Pumps, Final report, Part
2015.
Wilk V, Helminger F, Lauermann M, Sporr A, Windholz
B. High temperature heat pumps for drying
–
first
results of operation in industrial environment. 13th IEA
Heat Pump Conference, Jeju Korea. 2021.
Kirova-Yordanova, Z., Thermodynamic estimation of
CO2 removal processes from synthesis gas in ammonia
production plants: comparison of efficiency and
environmental
impact
in
32nd
International
Conference on Efficiency, Cost, Optimization,
Simulation And Environmental Impact Of Energy
Systems - ECOS 2019, June 23-28. 2019: Wroclaw,
Poland.
Xiaoxue Kou, Ruzhu Wang, Shuai Du, Zhenyuan Xu,
Xuancan Zhu. Heat pump assists in energy transition:
Challenges and approaches. DeCarbon 3 (2024)
100033.
https://doi.org/10.1016/j.decarb.2023.100033
Jie Ji, Gang Pei, Tin-tai Chow, Wei He, Aifeng Zhang, Jun
Dong, Hua Yi, Performance of multi-functional
domestic heat-pump system, Appl. Energy 80 (3) (2005)
307
–
326,
https://doi.org/10.1016/j.apenergy.2004.04.005.
Xenia Kirschstein, Max Ohagen, Joscha Reber, Philip J.
Vardon, Nadja Bishara. Regeneration of shallow
borehole heat exchanger fields: A literature review.
Energy
&
Buildings
317
(2024)
114381.
https://doi.org/10.1016/j.enbuild.2024.114381
Sergej Belik, Volker Dreissigacker, Stefan Zunft. Power-
to-heat integration in regenerator storage: Enhancing
thermal storage capacity and performance. Journal of
Energy
Storage
50
(2022)
104570.
https://doi.org/10.1016/j.est.2022.104570.
. H.C. Mantripragada, H. Zhai, E.S. Rubin, Boundary
Dam or Petra Nova
–
Which is a better model for CCS
energy supply? Int. J. Greenhouse Gas Control 82
American Journal of Applied Science and Technology
60
https://theusajournals.com/index.php/ajast
American Journal of Applied Science and Technology (ISSN: 2771-2745)
(2019) 59
–
68.
