RENEWABLE ENERGY SOURCES IN HEAT PUMPS FOR ENERGY EFFICIENT LOW-TEMPERATURE DRYING OF SEED GRAIN
High energy costs for the process of drying seed grain materials require the development of advanced energy-efficient technologies. Drying seed materials requires soft drying modes, so it is not possible to dry them at high temperatures, which is related to the quality of the material. The analyzed...
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| Дата: | 2025 |
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Institute of Renewable Energy National Academy of Sciences of Ukraine
2025
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Vidnovluvana energetika| _version_ | 1871103940368531456 |
|---|---|
| author | Sniezhkin , Yu. Paziuk , V. Samoilenko , K. Dakhnenko, V. Biriukov , S. |
| author_facet | Sniezhkin , Yu. Paziuk , V. Samoilenko , K. Dakhnenko, V. Biriukov , S. |
| author_institution_txt_mv | [
{
"author": "Yu. Sniezhkin ",
"institution": "Institute of Engineering Thermophysics of NAS of Ukraine, Kyiv, Ukraine"
},
{
"author": "V. Paziuk ",
"institution": "Institute of Engineering Thermophysics of NAS of Ukraine, Kyiv, Ukraine"
},
{
"author": "K. Samoilenko ",
"institution": "Institute of Engineering Thermophysics of NAS of Ukraine, Kyiv, Ukraine"
},
{
"author": "V. Dakhnenko",
"institution": "Institute of Engineering Thermophysics of NAS of Ukraine, Kyiv, Ukraine"
},
{
"author": "S. Biriukov ",
"institution": "Institute of Engineering Thermophysics of NAS of Ukraine, Kyiv, Ukraine"
}
] |
| author_sort | Sniezhkin , Yu. |
| baseUrl_str | https://ve.org.ua/index.php/journal/oai |
| collection | OJS |
| datestamp_date | 2026-07-18T06:32:22Z |
| description | High energy costs for the process of drying seed grain materials require the development of advanced energy-efficient technologies. Drying seed materials requires soft drying modes, so it is not possible to dry them at high temperatures, which is related to the quality of the material. The analyzed methods of drying rapeseed indicate that the main method of drying is convective. There is a problem with high energy costs for the process, which is associated with low-temperature drying and the imperfection of existing drying equipment. Also, existing drying methods such as sublimation, infrared, microwave and ultrasonic in this case will significantly affect the quality of the material, so it is undesirable to use them. Therefore, to enhance the intensity of drying, if it is necessary to create a low-temperature drying process, the condensation method of drying is employed, alongside a reduction in the moisture content of the heat carrier. 
The application of this technology solves a number of tasks, such as: economy, environmental friendliness, manufacturability and operational expediency of the drying unit. The presented research solves the urgent task of intensity and economy, preservation of all seed properties of the material, using the example of rapeseed. Based on the presented tasks for improving the operation of the seed dryer, an installation with an installed heat generator on a heat pump (HP) was developed, which allows for implementing and solving all the stated tasks.
As a result of the research, when comparing a drying plant with a heat pump to a drying plant with electric heating by electric heaters, the quality of rapeseed improved by 3%, the specific heat consumption decreased by 3.3 times, the intensity increased by 13%, the efficiency of the drying plant with the heat pump increased to 58.4 %. |
| doi_str_mv | 10.36296/1819-8058.2025.2(81).173-181 |
| first_indexed | 2025-07-17T11:40:04Z |
| format | Article |
| fulltext |
173
Відновлювана енергетика. № 2/2025 | Геотермальна енергетика
УДК 664.723.047; 664.8.047 https://doi.org/10.36296/1819-8058.2025.2(81).173-181
RENEWABLE ENERGY SOURCES IN HEAT PUMPS FOR ENERGY EFFICIENT
LOW-TEMPERATURE DRYING OF SEED GRAIN
Received Feb. 09, 2025; accepted Jun. 27, 2025
Available online Jun. 30, 2025
Sniezhkin Yu.1, Paziuk V.2, Samoilenko K.3,
Dakhnenko V.4, Biriukov S.5
Author for correspondence: Samoilenko Kateryna,
e-mail: katerynasamoilenkoittf@gmail.com
Abstract. High energy costs for the process of drying seed grain
materials require the development of advanced energy-efficient
technologies. Drying seed materials requires soft drying modes,
so it is not possible to dry them at high temperatures, which is
related to the quality of the material. The analyzed methods of
drying rapeseed indicate that the main method of drying is con-
vective. There is a problem with high energy costs for the pro-
cess, which is associated with low-temperature drying and the
imperfection of existing drying equipment. Also, existing drying
methods such as sublimation, infrared, microwave and ultra-
sonic in this case will significantly affect the quality of the material, so it is undesirable to use them. Therefore, to
enhance the intensity of drying, if it is necessary to create a low-temperature drying process, the condensation
method of drying is employed, alongside a reduction in the moisture content of the heat carrier.
The application of this technology solves a number of tasks, such as: economy, environmental friendliness, manu-
facturability and operational expediency of the drying unit. The presented research solves the urgent task of in-
tensity and economy, preservation of all seed properties of the material, using the example of rapeseed. Based on
the presented tasks for improving the operation of the seed dryer, an installation with an installed heat generator
on a heat pump (HP) was developed, which allows for implementing and solving all the stated tasks.
As a result of the research, when comparing a drying plant with a heat pump to a drying plant with electric heating
by electric heaters, the quality of rapeseed improved by 3%, the specific heat consumption decreased by 3.3 times,
the intensity increased by 13%, the efficiency of the drying plant with the heat pump increased to 58.4 %.
Keywords: energy efficiency, drying unit, heat pump, germination, rapeseed.
ВІДНОВЛЮВАНІ ДЖЕРЕЛА ЕНЕРГІЇ В ТЕПЛОВИХ НАСОСАХ ДЛЯ ЕНЕРГОЕФЕКТИВНOГО
НИЗЬКОТЕМПЕРАТУРНОГО СУШІННЯ НАСІННЄВОГО ЗЕРНА
Отримано 09 лют. 2025 р.; рекомендовано до публікації 27 черв. 2025 р.
Доступно онлайн 30 черв. 2025 р.
Снєжкін Ю. Ф.1, Пазюк В. М.2, Самойленко К. М.3,
Дахненко В. Л.4, Бірюков С. О.5
Автор для кореспонденції: Петрова Жанна,
e-mail: bergelzhanna@ukr.net
Анотація. Високі енергетичні витрати на процес су-
шіння насіннєвих зернових матеріалів вимагає розро-
бки передових енергоефективних технологій. Сушіння
насіннєвих матеріалів вимагає м’яких режимів су-
шіння, тобто неможливо їх сушити при високих тем-
пературах, що пов’язано з якістю матеріалу. Проана-
лізовані способи сушіння насіння ріпаку вказують на
те, що основним способом сушіння є конвективне.
1 Academician of the NAS of Ukraine, Dr. of
Science (Tech.), Professor
https://orcid.org/0000-0002-9049-3392
2 Corresponding Member of the NAS of Ukraine,
Dr. of Science (Tech.), Assoc. Professor
https://orcid.org/0000-0002-4955-1941
3 Cand. of Science (Tech.)
https://orcid.org/0000-0002-5169-4466
4 Cand. of Science (Tech.), Assoc. Professor
https://orcid.org/0009-0000-0463-5087
5 Postgraduate
https://orcid.org/0009-0005-4382-6587
1, 2, 3, 4, 5 Institute of Engineering Thermophysics
of NAS of Ukraine, Kyiv, Ukraine
1 Академік НАН України, д-р. техн. наук,
професор
https://orcid.org/0000-0002-9049-3392
2 д-р. техн. наук, доцент
https://orcid.org/0000-0002-4955-1941
3 канд. техн. наук
https://orcid.org/0000-0002-5169-4466
4 канд. техн. наук, доцент
https://orcid.org/0009-0000-0463-5087
5 аспірант
https://orcid.org/0009-0005-4382-6587
1, 2, 3, 4, 5 Інститут технічної теплофізики
НАН України, Київ, Україна
174
Відновлювана енергетика. № 2/2025 | Геотермальна енергетика
Існує проблема з високими енергетичними витратами на процес, що пов’язано з низькотемпера-
турним сушінням і недосконалістю існуючого сушильного обладнання. Також існуючи методи су-
шіння, такі як сублімаційний, інфрачервоний, мікрохвильовий та ультразвуковий в даному випадку
істотно вплинуть на якість матеріалу, тому їх небажано застосовувати. Тому для підвищення
інтенсивності сушіння, при необхідності створення низькотемпературного процесу сушіння, вико-
ристовують конденсаційний спосіб сушіння із зниженням вологовмісту теплоносія.
Застосування цієї технології вирішують ряд завдань, таких як: економічність, екологічність, техно-
логічність та експлуатаційна доцільність сушильної установки. Представлені дослідження вирішу-
ють актуальне завдання інтенсивності та економічності, збереження всіх насіннєвих властивостей
матеріалу на прикладі насіння ріпаку. Виходячи з представлених завдань із покращення роботи насін-
нєвої сушарки розроблена установка із встановленим теплогенератором на тепловому насосі (ТН),
яка дозволяє реалізувати та вирішити всі заявлені завдання.
В результаті проведених досліджень, при порівнянні сушильної установки із ТН та сушильної устано-
вки з електропідігрівом електрокалориферами, якість насіння ріпаку покращилось на 3%, питомі ви-
трати теплоти знизились в 3,3 раз, інтенсивність збільшилась на 13%, к.к.д. сушильної установки із
тепловим насосом збільшилось до 58,4%.
Бібл. 30, рис. 5, табл. 2.
Ключові слова: енергоефективність, сушильна установка, тепловий насос, схожість, насіння ріпаку.
Introduction. At the current stage of the development of
grain drying in the world, there is an urgent need to create
and develop highly efficient grain drying equipment that
would ensure minimal energy consumption and high seed
germination.
The urgency of the problem of energy saving during dehy-
dration is related to large volumes of grain: from 50% to
80%, and in adverse weather conditions even 100% of the
annually grown grain requires drying. On average, when
drying 1 ton of grain, it is necessary to remove 70 to 80 kg
of moisture, which with a harvest of 35 to 40 million tons
leads to costs of 0.4 to 0.7 million tons of conventional fuel
and significant labor costs. The time spent on drying grain
is up to 70% of the time of harvesting.
The drying process is regulated by the maximum heating
temperature of the seed material, which should not ex-
ceed 43 – 45 °С [1-5]. Our preliminary research on deter-
mining the maximum heating temperature of seed mate-
rial on the modern winter rapeseed variety Svitoch
(Vinnytsia Research Station, Ukraine) showed that it is
possible to carry out drying up to a grain temperature of
48 °С, at which seed germination is 97% (heat carrier tem-
perature 50 °C). [6].
Energy costs when drying food grain in modern and mod-
ernized dryers, the heat consumption can be about 4800-
5000 kJ/kg of evaporated moisture, and when drying seeds,
the costs increase by 30-40% or more, which is mainly
caused by low drying temperatures [6].
When drying seed material, it is not possible to intensify the
process by increasing the temperature of the coolant.
Therefore, there is a need to use another method of inten-
sification, which is achieved by reducing the moisture con-
tent of the heat carrier, which in turn increases the drying
speed and reduces the duration of the process.
The purpose of the work is to create advanced energy-ef-
ficient low-temperature seed grain drying technologies.
The winter rapeseed variety Svitoch (Vinnytsia Experi-
mental Station, Ukraine) and a grain drying unit with a heat
pump with a capacity of 20 kg/h were selected as the object
of drying.
During the research, experimental methods and state-of-
the-art means were used to measure drying parameters
with the help of an automated system for collecting and
processing information in a developed program on a spe-
cially designed and manufactured installation, and the ob-
tained data were processed in modern integrated Excel and
Mathcad systems. To assess the quality of rapeseed, the
standard research methods provided for by DSTU 4138 -
2002 were used. Theoretical studies were carried out tak-
ing into account the methods based on the main provisions
of the theory of heat and mass transfer, the theory of simi-
larity, which were processed with the help of computer
technologies.
Rapeseed moisture is calculated as a percentage:
%,100
12
32
−
−
=
mm
mm
W (1)
where m1 – mass of an empty box (with a lid), g;
m2 – the mass of the box with the sample before drying, g;
m3 – weight of the sample after drying, g.
To carry out research, a drying plant with HP was developed
at the Institute of Engineering Thermophysics of the Na-
tional Academy of Science of Ukraine (Fig. 1). Technical
characteristics of the grain drying plant with HP are pre-
sented in the Table 1.
175
Відновлювана енергетика. № 2/2025 | Геотермальна енергетика
Fig. 1. Experimental plant with HP for drying rapeseed:
1 – heat pump unit; 2 – control panel; 3 – time relay; 4 –
thermal relay; 5 – drying shaft; 6 – speed regulator; 7 –
electricity meter; 8 – scales; 9 – i-7018 analog-to-digital
converter, i-7520 interface converter and chromel-copel
thermoelectric converters; 10 computer; 11 – digital dis-
play of scales
Table 1. Technical characteristics of the grain drying plant
with HP
1. Productivity in terms of
extracted moisture
2 kg/h
2.
The temperature of the cool-
ant at the entrance to
the drying chamber
35 – 55 С
3. Refrigerant evaporation tem-
perature
0 – +5 С
4. Refrigerant R22
5.
The moisture content of the
coolant at the entrance to the
drying chamber
6 g/kg dry air
6. Heat carrier costs 250 – 800 m3/h
7.
Overall dimensions:
• drying chamber
• heat pump unit
0,32х0,32х0,48 m
0,7х0,9х1,3 m
8.
Compressor ZR49КЗЕ – ТFD:
• cooling capacity
• power of the electric motor
of the compressor
11,21 kW
4,08 kW
9.
Circulation fan Ц14-46 № 2,5
• power of the electric motor
• the number of revolutions
0,75 kW
1450 rpm
Methodology for conducting an experiment on a drying
plant with HP:
1. Before conducting experiments, we determine the initial
moisture content of rapeseed according to the formula 1. The
rapeseed is poured into boxes and dried in a laboratory dryer
at a temperature of 105 °С for 5 hours. Cool in a desiccator
with silica gel to prevent sorption of moisture from the air.
2. Conducting the experiment begins with turning on the
grain dryer with a heat pump and the computer system for
collecting and processing information, which continuously
records the time of the experiment, the temperature of the
drying agent, the temperature on the surface and in the
middle of the material layer, the change in the weight of
the sample.
3. After installation in a drying unit with HP drying mode, a
batch of seed rape is poured into a drying shaft and dried
to the final moisture content of rape – 8 %.
4. Two samples are taken from the batch of dried rape seed
obtained:
4.1. The first sample is used to determine the seed prop-
erties of the material
4.2. The second - determines the final moisture content
of the material by formula 1.
5. After determining the moisture content of the sample af-
ter drying, we calculate and construct the drying curves and
drying speed of rapeseed: W = f(τ), dW/dτ = f(W).
Methods of analysis of the germination of rape seeds:
1. Thermostats once every 10 days, and dishes before each
analysis are washed with hot water and detergents and dis-
infected with a 1% solution of potassium permanganate or
alcohol. A tray with water is placed in the working chamber
of the thermostat. Petri dishes are sterilized in an oven at a
temperature of (130 +2) °С for an hour.
2. Germination analysis is carried out on rapeseed seeds
isolated during the determination of purity. For this pur-
pose, 100 seeds are arbitrarily counted. Seeds are evenly
placed on moistened filter paper. Analysis of seeds is car-
ried out on one layer of moistened paper placed in Petri
dishes. Petri dishes are covered with glass plates or lids.
3. Analysis of rape seed germination under different drying
modes is carried out at a temperature of 20 °С for 7 days.
We determine the energy of germination and germination
of seeds on abnormal seedlings (damaged, weak, rotten,
underdeveloped and dead) on the 2nd, 4th and 7th day, re-
spectively.
The given methods make it possible to analyze the obtained
research results with the aim of determining an energy-ef-
ficient rational mode of drying rapeseed.
Results and Discussion. Experimental studies were carried
out in the following stages:
The first stage. Setting the effective moisture content of the
heat carrier in the dryer with HP.
Determination of the value of the required moisture param-
eter of the heat carrier when drying rapeseed in a drying unit
with a heat pump was carried out according to the I - d dia-
gram on the saturation line φ = 100% and was chosen de-
pending on the temperature of the evaporator НР (Fig. 2).
The conversion factor of the heat pump also depends on
the temperature of the evaporator and the HP condenser
(Fig. 3).
176
Відновлювана енергетика. № 2/2025 | Геотермальна енергетика
Fig. 2. Dependence of the moisture content of the heat carrier on the temperature of the HP evaporator with the
ZR49K3E - TFD Copeland ZR compressor when working on R 22 freon
Fig. 3. Dependence of the conversion coefficient on the temperature change of the evaporator and condenser of the HP
with the ZR49K3E compressor - TFD of the Copeland ZR company when operating on R 22 freon
Determination of the moisture content of the heat carrier
in the heat pump can be adjusted and depends on the tem-
peratures at the condenser and the HP evaporator. Deter-
mination of the moisture content of the heat carrier is car-
ried out by comprehensively analyzing figures 2,3. The
value of the moisture content is limited (Fig. 2) by the tem-
perature of the evaporator of the heat pump (it must be
higher than the temperature of 0 °C, so that the evaporator
does not freeze) and the temperature of the HP condenser
(the necessary optimal operating temperature HP (ob-
tained according to our own research) for seed grain is 50 °С).
An increase in the temperature of the HP evaporator in-
creases the moisture content of the coolant (Fig. 2) and the
HP conversion factor (μ) (Fig. 3). To increase the intensity
of drying, it is necessary to reduce the moisture content of
the heat carrier, and to increase energy efficiency, the con-
version factor of НР should be increased. Therefore, the op-
timal operation mode of HP is determined: the tempera-
ture of the HP evaporator is 5 °С, the temperature of the
HP condenser is 50 °С, the moisture content of the heat car-
rier is d = 6 g/kg evaporated moisture, the HP conversion
factor is μ = 3.2.
II stage. Increasing the intensity of drying rapeseed in a dry-
ing unit with HP.
The study of the effectiveness of the rape seed drying pro-
cess in a condensation drying unit with HP is carried out by
comparing it with the usual convective drying method with
electric heating (instead of HP, a block of heaters with a ca-
pacity of 7.5 kW is installed). That is, the moisture content
of the heat carrier at the exit from the heat pump is 6 g/kg
dry air and we compare it with the moisture content of the
environment without a heat pump of 10 g/kg dry air with
heating of the coolant with the help of electric heaters.
From Fig. 4 shows that a decrease in the moisture content
of the heat carrier accelerates the drying time of rapeseed
by 13%. The final temperature of the heat carrier in a 20
mm layer of rapeseed and with a final grain moisture con-
tent of 8% is 40.9 °С, with electric heating - 41.2 °С.
The kinetics of the rapeseed drying process according to
the obtained experimental data were described using poly-
nomials of the 2nd degree (1 – 2) with the reliability of the
approximation R2 = 0.9998.
177
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For air moisture content d = 6 g/kg dry air with a heat pump:
346,192978,00017,0 2
6 +−= W (2)
For air moisture content d = 10 g/kg dry air with electric heating:
32,192855,00012,0 2
10 +−= W (3)
Fig. 4. Kinetics of the process and temperature curves of rape seed drying with:
1,3 – heat pump (d = 6 g/ kg dry air, μт = 3,2); 2,4 – electric heating (d = 10 g/ kg dry air).
t = 50 °С, V = 1,2 m/s, Win = 19,2%, δ = 20 mm
Fig. 5. Rapeseed drying speed curves at different moisture contents of the coolant:
1 – heat pump (d = 6 g/ kg dry air, μт = 3,2); 2 – electric heating (d = 10 g/ kg dry air).
t = 50 °С, V = 1,2 m/s, Win = 19,2%, δ = 20 mm
Fig. 6. Generalized curve of rape seed drying speed in semi-logarithmic coordinates
178
Відновлювана енергетика. № 2/2025 | Геотермальна енергетика
As can be seen from the drying speed curves, the drying of
rapeseed with different moisture content of the heat car-
rier goes through periods of heating, constant and falling
drying speed (Fig. 5). The lower the moisture content of
the air, the faster the rapeseed drying rate. The maximum
rate of rapeseed drying at the air moisture content of 6 g/kg
dry air, at the end of the period of constant drying speed,
at the critical point K1 is 0.283%/min, and at the air mois-
ture content of 10 g/kg dry air – 0.243%/min., which is less
by 14.2%. At point K2, the difference in drying speed is 4.4%,
and at the end of the period of falling drying speed, this dif-
ference decreased by 3.0%.
To describe the drying process of rapeseed, a generalized
drying speed curve was constructed in semi-logarithmic co-
ordinates (Fig. 6).
When drying rapeseed in a drying unit with HP, at the be-
ginning of the process, the material is briefly heated, then
it is dried in a period of constant drying speed and at the
end in a period of falling drying speed, which consists of
two stages.
It can also be seen from the generalized curve of rape seed
drying speed constructed in semi-logarithmic coordinates
that it is a broken line, the break of which occurs at mois-
ture content 1Wк = 16.6% and humidity Wk2= 11.8%. The
law of change of N* (dW/dτ) during the transition of con-
stant drying speed to 1 and 2 periods of falling drying speed
changes, which indicates a difference in the kinetics of dry-
ing in different parts of the second period
The value of N*, not taking into account the heating stage in
the period of constant drying speed, has a linear dependence:
1* =N , (4)
2,196,16 W
in the 1st part of the second period is determined by the
following empirical dependence:
WеN 0852,02713,0*= , (5)
6,168,11 W
in the second part of the second period is equal:
WеN 1867,00927,0*= , (6)
8,110,8 W
III stage. Increasing the energy efficiency of rape seed dry-
ing in a drying plant with HP.
Energy consumption was estimated by specific heat con-
sumption per kg of evaporated moisture during drying in a
drying plant with HP. The specific heat consumption in the
drying plant with HP was recorded based on the change in
electricity consumption on the meter and the change in
mass during drying on the scales installed under the drying
shaft. The main characteristics of the rapeseed drying pro-
cess are the time of the experiment and the moisture con-
tent of the material, therefore, to characterize the energy
costs of the drying process, we cite two dependencies: Q=
f (τ) and Q= f (W) and their obtained equations (Fig. 7, 8).
We describe Fig. 8 starting from 3 min, so at the beginning
of the rapeseed drying process, the specific heat consump-
tion for 3 min (at a humidity of 18.4%) is 3272 kJ/kg of evap-
orated moisture, then the heat consumption increases in
the middle of the process for 28 min ( at a humidity of
12.1%) they amount to 3,600 kJ/kg of evaporated moisture,
that is the increase occurred by 10% or by 13.12 kJ/min or
by 52 kJ/% humidity. The process continues from 28 to 54
min (from moisture content 12.1 to 8%), where the inten-
sity of drying decreases and the specific heat consumption
increases by 24.4% or by 33.84 kJ/min or by 214.63 kJ/%
moisture content. The total increase in specific heat con-
sumption during drying of rapeseed at a drying time of 54
minutes is 36.9%.
That is, based on the results of research, the specific heat con-
sumption during drying of rapeseed from the initial moisture
content of 19.2% to the final moisture content of 8% is 4480
kJ/kg of evaporated moisture or 467kJ/kg of dry product.
Fig. 7. Specific heat consumption from the time of the experiment in the drying unit with HP:
t = 50 °С, V = 1,2 m/s, Win = 19,2%, δ = 20 mm, d = 6 g/ kg dry air, μт = 3,2
179
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Fig. 8. Specific heat consumption from material humidity in a drying unit with HP:
t = 50 °С, V = 1,2 m/s, Win = 19,2%, δ = 20 mm, d = 6 g/kg dry air., μт = 3,2
Fig. 9. Comparison of specific heat consumption from the method of preparation of the heat carrier
Comparing the specific heat consumption during drying of
rapeseed in a drying plant with different methods of pre-
paring the heat carrier, the heat pump, compared to the
usual heating of the heat carrier in the heater, allows to re-
duce energy consumption by 3.281 times (Fig. 9).
The value of reduced heat energy consumption μp = 3,281
and there is an established practical HP conversion factor,
which differs from the theoretical one established when se-
lecting the drying mode (according to TN operation sched-
ules on R 22 freon, Fig. 4, 5) μт = 3,2. The difference is 2.5 %.
The evaluation of the quality of the dryer is evaluated by its
energy coefficient of useful action η (coefficient of useful
action), which is determined by the ratio of useful energy
Quseful to all the energy spent on the process Qspent:
𝜂 =
𝑄𝑢𝑠𝑒𝑓𝑢𝑙
𝑄𝑠𝑝𝑒𝑛𝑡
=
𝑟 + Δ𝑟
𝑄𝑐𝑎𝑙𝑜𝑟
=
2382 + 238
4480
= 58,4 (7)
where: r – specific heat of evaporation of moisture, kJ/kg.
Q calor – energy spent on heating the heat carrier in the
heater, kJ/kg of evaporated moisture.
From the given calculation in formula 5 coefficient of useful
action drying plant with HP is η = 53.2, and with electric
heating η = 16.2.
IV stage. Comparison of the intensity and energy efficiency
of rape seed drying in a drying plant with HP.
The intensity of the rape seed drying process in a heat
pump grain dryer can be estimated by the moisture elastic-
ity of the volume of the dryer, that is the amount of mois-
ture evaporated from 1 m3 of its volume per hour.
If we compare the change in drying intensity and the
specific heat consumption from the moisture content
of rapeseed in the drying mode t = 50 °С, V = 1.2 m/s,
δ = 20 mm, d = 6 g/kg dry air, we can observe the fol-
lowing dependence: at the beginning of the drying pro-
cess, the intensity is high - the specific heat consump-
tion is small, gradually the intensity decreases, and the
consumption increases (Fig. 10). The optimal value of
the intensity of 36 kg/m3 h and the average specific
heat consumption of 3675 kJ/kg is at point K2 at a hu-
midity of 11.8 %.
180
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Comparing the obtained data on the average intensity of the
heat pump grain dryer with direct flow mine grain dryers, the
intensity of the process increases by 1.5-2 times (Table 2).
V stage. Rapeseed seed quality after drying in a drying unit
with HP.
The similarity of rapeseed in the drying plant with HP in
relation to the original rapeseed is 100%, which indi-
cates the high quality of the drying process (Table 3).
Germination energy on day 2-4 changes from the origi-
nal by 1 %.
Fig. 10. Determination of the optimal moisture content of rapeseed in the intensive drying mode
(t = 50 °С, V = 1.2 m/s, δ = 20 mm, d = 6 g/kg dry air) when comparing intensity and specific heat consumption
Table 2. The average intensity of rapeseed drying depending on the type of grain dryer
Type of grain dryer
Direct-flow mines Drying installation with
HP DSP – 24 DSP – 32
Moisture tension (intensity), kg/m3 h 20.5 28.4 30 - 42
Table 3. The influence of process parameters on the quality of rapeseed during drying in a HP dryer
№ Process parameters Quality parameters
The method of
preparation of the
heat carrier / the
temperature of the
heat carrier
t, ºС
Speed of
movement
V, m/s
Layer
thickness
δ, mm
Initial seed
moisture
W, %
Germination en-
ergy
Е, %
7th day of germination
С,%
2 day 4 day abs/rel
1 Initial rapeseed 83 5 100
21 HP / 50 1,2 20 19,2 82 84 100
22 Electric heating / 50 1,2 20 19,2 80 82 97
Germination of rapeseed depends on the method of heat-
ing the heat carrier, for example, at a temperature of 50 °С
in a dryer with HP, the germination is 100%, and with elec-
tric heating it is 97% [6]. That is, 3% of the seed material is
lost.
The Institute of Engineering Thermophysics of the National
Academy of Sciences of Ukraine also carried out research
on various seed materials and established rational drying
regimes with high germination [7 - 9].
Conclusions
The application of advanced energy-efficient low-tempera-
ture technologies in the study of drying seed materials
yielded the following results:
1. The effective moisture content of the heat carrier in the
dryer with a heat pump has been established, which should
be less than 10 but more than 4 g/kg dry air. It was deter-
mined that at a heat carrier temperature of 50 °C and a
moisture content of 6 g/kg dry air, the conversion factor of
the heat pump is 3.2.
181
Відновлювана енергетика. № 2/2025 | Геотермальна енергетика
2. Increasing the intensity of seed drying is achieved by re-
ducing the moisture content of the heat carrier. The task is
solved by developing a drying unit with a heat pump at a
low temperature drying of 50 °C and a coolant moisture
content of 6 g/kg dry air with 13 % increase in process in-
tensity.
3. The energy efficiency of the installation is determined by
its specific consumption, which is 4480 kJ/kg of evaporated
moisture (with a decrease in rapeseed moisture from 19.2
to 8%), which is 7-12% lower than analogues. The efficiency
of the drying installation with a heat pump is 58.4%.
4. The germination rate of grain after drying in a heat pump
installation is 100%, making it possible to recommend this
technology for drying seed material.
REFERENCES
1. Broker, D.B., Bakker-Arkema, F.W., Hall C.W. (1974).
Drying cereal grains. Westport: AVI. 265.
2. Franca, Neto, J.B., Henning, A.A., Krzyzanowski, F.C.
(1994). Soybean seed drying. Seed production and tech-
nology for the tropics. In: EMBRAPA. Centro Nacional de
Pesquisa de Soja. Tropical soybean: improvement and
production. Rome: FAO, 217–240. Boyd, A.H. Heated air
drying of soybean (Glycine max (L.) Merrill) seed. 90f.
Dissertation (Doctor of Philosophy) - Faculty of Missis-
sippi State University, Mississippi State, 1974.
3. Boyd, A.H. (1974). Heated air drying of soybean (Glycine
max (L.) Merrill) seed. 90f. Dissertation (Doctor of
Philosophy) - Faculty of Mississippi State University,
Mississippi State.
4. Krzyzanowski, F.C., West, S.H., Franca, Neto J.B. (2006).
Drying soybean seed using air ambient temperature at
low relative humidity. Revista Brasileira de Sementes.
28 (2), 77–83.
5. Afrakhteh, S., Frahmandfar, E., Hamidi, A., Ramandi, H.
(2013). Evaluation of Growth Characteristics and Seed-
ling Vigor in Two Cultivars of Soybean dried under dif-
ferent Temperature and Fluidized bed dryer. Intl J Agri
Crop Sci. 5 (21). 2537–2544.
6. Paziuk, V.M., Petrova, Z.O., Tokarchuk, O.A., Yaropud,
V.M. (2019). Research of rational modes of drying rape
seed. INMATEH - Agricultural Engineering, 58 (2), 303–
310.
7. Snezhkin, Yu.F., Paziuk, V.M., Petrova, Zh.O., Tokarchuk,
O.A. (2020). Determination of the energy efficient
modes for barley seeds drying. INMATEH - Agricultural
Engineering. 61 (2), 183–192.
8. Paziuk, V., Vyshnevskiy, V., Tokarchuk, O., Kupchuk I.
(2021). Substation of the energy efficient schedules of
drying grain seeds. Bulletin of the Transilvania Univer-
sity of Braşov Series II: Forestry, Wood Industry, Agricul-
tural Food Engineering, 14 (63), 2, 137–146.
9. Paziuk, V., Petrova, Zh., Tokarchuk, O., Polievoda, Yu.
(2021). Special aspects of soybean drying with high
seedling vigor. University.Pjlstehnica of Buharest Scien-
tific Bulletin, Series D, 83 (2), 327–336.
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| id | veorgua-article-538 |
| institution | Vidnovluvana energetika |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-07-19T01:16:11Z |
| publishDate | 2025 |
| publisher | Institute of Renewable Energy National Academy of Sciences of Ukraine |
| record_format | ojs |
| resource_txt_mv | veorgua/b7/c30fa183ed8a0ca54b73ddb56a6f59b7.pdf |
| spelling | veorgua-article-5382026-07-18T06:32:22Z RENEWABLE ENERGY SOURCES IN HEAT PUMPS FOR ENERGY EFFICIENT LOW-TEMPERATURE DRYING OF SEED GRAIN ВІДНОВЛЮВАНІ ДЖЕРЕЛА ЕНЕРГІЇ В ТЕПЛОВИХ НАСОСАХ ДЛЯ ЕНЕРГОЕФЕКТИВНOГО НИЗЬКОТЕМПЕРАТУРНОГО СУШІННЯ НАСІННЄВОГО ЗЕРНА Sniezhkin , Yu. Paziuk , V. Samoilenko , K. Dakhnenko, V. Biriukov , S. energy efficiency, drying unit, heat pump, germination, rapeseed. енергоефективність, сушильна установка, тепловий насос, схожість, насіння ріпаку. High energy costs for the process of drying seed grain materials require the development of advanced energy-efficient technologies. Drying seed materials requires soft drying modes, so it is not possible to dry them at high temperatures, which is related to the quality of the material. The analyzed methods of drying rapeseed indicate that the main method of drying is convective. There is a problem with high energy costs for the process, which is associated with low-temperature drying and the imperfection of existing drying equipment. Also, existing drying methods such as sublimation, infrared, microwave and ultrasonic in this case will significantly affect the quality of the material, so it is undesirable to use them. Therefore, to enhance the intensity of drying, if it is necessary to create a low-temperature drying process, the condensation method of drying is employed, alongside a reduction in the moisture content of the heat carrier.  The application of this technology solves a number of tasks, such as: economy, environmental friendliness, manufacturability and operational expediency of the drying unit. The presented research solves the urgent task of intensity and economy, preservation of all seed properties of the material, using the example of rapeseed. Based on the presented tasks for improving the operation of the seed dryer, an installation with an installed heat generator on a heat pump (HP) was developed, which allows for implementing and solving all the stated tasks. As a result of the research, when comparing a drying plant with a heat pump to a drying plant with electric heating by electric heaters, the quality of rapeseed improved by 3%, the specific heat consumption decreased by 3.3 times, the intensity increased by 13%, the efficiency of the drying plant with the heat pump increased to 58.4 %. Високі енергетичні витрати на процес сушіння насіннєвих зернових матеріалів вимагає розробки передових енергоефективних технологій. Сушіння насіннєвих матеріалів вимагає м’яких режимів сушіння, тобто неможливо їх сушити при високих температурах, що пов’язано з якістю матеріалу. Проаналізовані способи сушіння насіння ріпаку вказують на те, що основним способом сушіння є конвективне. Існує проблема з високими енергетичними витратами на процес, що пов’язано з низькотемпературним сушінням і недосконалістю існуючого сушильного обладнання. Також існуючи методи сушіння, такі як сублімаційний, інфрачервоний, мікрохвильовий та ультразвуковий в даному випадку істотно вплинуть на якість матеріалу, тому їх небажано застосовувати. Тому для підвищення інтенсивності сушіння, при необхідності створення низькотемпературного процесу сушіння, використовують конденсаційний спосіб сушіння із зниженням вологовмісту теплоносія.  Застосування цієї технології вирішують ряд завдань, таких як: економічність, екологічність, технологічність та експлуатаційна доцільність сушильної установки. Представлені дослідження вирішують актуальне завдання інтенсивності та економічності, збереження всіх насіннєвих властивостей матеріалу на прикладі насіння ріпаку. Виходячи з представлених завдань із покращення роботи насіннєвої сушарки розроблена установка із встановленим теплогенератором на тепловому насосі (ТН), яка дозволяє реалізувати та вирішити всі заявлені завдання. В результаті проведених досліджень, при порівнянні сушильної установки із ТН та сушильної установки з електропідігрівом електрокалориферами, якість насіння ріпаку покращилось на 3%, питомі витрати теплоти знизились в 3,3 раз, інтенсивність збільшилась на 13%, к.к.д. сушильної установки із тепловим насосом збільшилось до 58,4%. Бібл. 30, рис. 5, табл. 2. Institute of Renewable Energy National Academy of Sciences of Ukraine 2025-06-30 Article Article application/pdf https://ve.org.ua/index.php/journal/article/view/538 10.36296/1819-8058.2025.2(81).173-181 Vidnovluvana energetika ; No. 2(81) (2025): Scientific and applied Journal renewable energy ; 173-181 Возобновляемая энергетика; ##issue.no## 2(81) (2025): Scientific and applied Journal renewable energy ; 173-181 Відновлювана енергетика; № 2(81) (2025): Науково-прикладний журнал Відновлювана енергетика; 173-181 2664-8172 1819-8058 10.36296/1819-8058.2025.2(81) en https://ve.org.ua/index.php/journal/article/view/538/446 Copyright (c) 2025 Yu. Sniezhkin , V. Paziuk , K. Samoilenko , V. Dakhnenko, S. Biriukov https://creativecommons.org/licenses/by-nc-nd/4.0 |
| spellingShingle | energy efficiency drying unit heat pump germination rapeseed. Sniezhkin , Yu. Paziuk , V. Samoilenko , K. Dakhnenko, V. Biriukov , S. RENEWABLE ENERGY SOURCES IN HEAT PUMPS FOR ENERGY EFFICIENT LOW-TEMPERATURE DRYING OF SEED GRAIN |
| title | RENEWABLE ENERGY SOURCES IN HEAT PUMPS FOR ENERGY EFFICIENT LOW-TEMPERATURE DRYING OF SEED GRAIN |
| title_alt | ВІДНОВЛЮВАНІ ДЖЕРЕЛА ЕНЕРГІЇ В ТЕПЛОВИХ НАСОСАХ ДЛЯ ЕНЕРГОЕФЕКТИВНOГО НИЗЬКОТЕМПЕРАТУРНОГО СУШІННЯ НАСІННЄВОГО ЗЕРНА |
| title_full | RENEWABLE ENERGY SOURCES IN HEAT PUMPS FOR ENERGY EFFICIENT LOW-TEMPERATURE DRYING OF SEED GRAIN |
| title_fullStr | RENEWABLE ENERGY SOURCES IN HEAT PUMPS FOR ENERGY EFFICIENT LOW-TEMPERATURE DRYING OF SEED GRAIN |
| title_full_unstemmed | RENEWABLE ENERGY SOURCES IN HEAT PUMPS FOR ENERGY EFFICIENT LOW-TEMPERATURE DRYING OF SEED GRAIN |
| title_short | RENEWABLE ENERGY SOURCES IN HEAT PUMPS FOR ENERGY EFFICIENT LOW-TEMPERATURE DRYING OF SEED GRAIN |
| title_sort | renewable energy sources in heat pumps for energy efficient low-temperature drying of seed grain |
| topic | energy efficiency drying unit heat pump germination rapeseed. |
| topic_facet | energy efficiency drying unit heat pump germination rapeseed. енергоефективність сушильна установка тепловий насос схожість насіння ріпаку. |
| url | https://ve.org.ua/index.php/journal/article/view/538 |
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