Potential of thermal energy accumulation in distric heating systems networks
When using the electrothermal consumers-controllers (ETCC) in distric heating (DH) systems for frequency control, and for active power it is important to know their power during the heating and non-heating seasons and dependency of such power on the ambient temperature. Currently these issues are no...
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| Дата: | 2014 |
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| Мова: | Українська |
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General Energy Institute of the National Academy of Sciences of Ukraine
2014
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System Research in Energy| _version_ | 1871104002379218944 |
|---|---|
| author | Derii V.O. |
| author_facet | Derii V.O. |
| author_institution_txt_mv | [
{
"author": "Derii V.O.",
"institution": null
}
] |
| author_sort | Derii V.O. |
| baseUrl_str | https://systemre.org/index.php/journal/oai |
| collection | OJS |
| datestamp_date | 2026-07-18T12:57:41Z |
| description | When using the electrothermal consumers-controllers (ETCC) in distric heating (DH) systems for frequency control, and for active power it is important to know their power during the heating and non-heating seasons and dependency of such power on the ambient temperature. Currently these issues are not studied completely that can be an obstacle to mass adoption of ETCC in DH systems.Total capacity of standard heat generators and ETCC transferred to the networks is distributed as follows: one part of it is designed to compensate the losses, the second part – to compensate heat load of consumers, and the third part causes the heat energy accumulation, which circulates in the networks.The conducted studies have shown that during the heating season the value of accumulated heat in the networks is directly proportional to the ambient air temperature. This dependency is expressed by a piecewise linear function. When ambient air temperature is smaller than calculated one, accumulation in heat networks is impossible. This can be explained by the fact that the parameters of the heat carrier reached the maximum permissible values for safety operation of the network, all energy in the network compensates the heat load and losses. When increasing ambient air temperature, the accumulation potential increases reaching a maximum value at the culminating point of the temperature chart.During non-heating season the only load of DH system is hot water. Heat carrier consumption is 2-3 times smaller than during the heating season. Heat energy accumulation time in the networks coincides with time of minimum hot water distribution. In order to be within the maximum heat carrier temperature in the return pipeline, heat energy can be accumulated at the expanse of increasing the heat carrier consumption at constant temperature in the supply pipeline. The value of accumulated heat energy will be much lower than during the heating season. |
| first_indexed | 2026-03-24T02:02:08Z |
| format | Article |
| fulltext |
29ISSN 1562-8965. Проблеми загальної енергетики, 2014, вип. 4 (39)
UDC 621.643.053 V.O. DERII, Cand. Sci. (Eng.)
Institute of General Energy National Academy of Sciences of Ukraine,
03680, Ukraine, Kyiv, Antonovycha st., 172
POTENTIAL OF THERMAL ENERGY ACCUMULATION IN DISTRIC HEATING SYSTEMS NETWORKS
The dependency of power causing heat energy accumulation in the networks on the ambient
air temperature was analyzed. Accumulation potential of heating and non-heating seasons
was determined. It was demonstrated that in ambient air temperatures below the minimum
design temperature the heat accumulation in networks is impossible.
K e y w o r d s: heating networks, accumulation, heat load, temperature chart, heating power,
heat carrier consumption, heat carrier temperature, potential.
Formulation of the problem. In using of elec-
trothermal consumers-controllers (ETCC) in dis-
tric heating (DH) systems for frequency control and
active power it is important to know what their
power in the heating and non-heating periods can
be and the how this power depends on the ambient
air temperature. Currently these issues is studied
insufficiently that can hamper ETCC implementa-
tion in DH systems.
Accumulation in heat supply network was stud-
ied in a number of works [1-3], covering the opera-
tion modes of heat consuming equipment during
accumulation of heat energy in the networks, as
well as limiting technical and institutional factors
and issues on improving the reliability of thermal
networks. These studies did not considered the
dependency of power, causing the thermal energy
accumulation in the networks, on the ambient air
temperature.
The objective of the work is to determine the
potential of thermal energy accumulation in the
networks and its dependency on temperature.
Heat capacity accumulation is basically in heat-
ing systems. First a heat source heats the carrier (in
fact the process of heat energy accumulation in the
carrier takes place), then the carrier transfer the
accumulated heat to consumers. Hereinafter the
process of heat accumulation in the heat supply
networks means the increasing of number of net-
works heat by excessing the temperatures and/or
heat carrier consumption, regulated with tempera-
ture chart.
The power supplied to the networks is distributed
as follows: one part of it comes to loss compensa-
tion, the other – to cover the heat load of con-
sumers, and the third one causes accumulation of
heat energy circulating in the networks.
The intensity of heat losses depends on many
factors: carrier temperature, condition of insula-
tion, pipe laying method, weather conditions,
groundwater level, etc. In the first approximation,
the heat losses can be taken as a percentage of
power at the input of heat networks. Taking into
account the above mentioned the balance of powers
for the heating network with or without
accumulation can be written as
Pм = Pн + δPм + Pa, (1)
Pt = Pн + δPt , (2)
where Pм, Pt – power, which is supplied to the heat-
ing network, in accordance with and without
accumulation;
Pн – power covering the heat load;
Pa – power causing the accumulation in the heat
networks;
δ – relative heat losses in the networks.
Based on (1) and (2) we can show that
© V.O. DERII, 2014
30 ISSN 1562-8965. Проблеми загальної енергетики, 2014, вип. 4 (39)
V.O. DERII
Pa = (Pм – Pt)(1 – δ). (3)
Neglecting minor changes in specific heat and
density depending on the temperature [4], we can
express Pм, Pt through the heat carrier consump-
tion, temperature difference, specific heat capacity
and density of the heat carrier. Then the formula (3)
will take the form
Pa = KCρ(G2 ΔTA – G1 ΔTt)(1 – δ), (4)
whereG1, G2 – heat carrier consumption in the
steady mode (according to the temperature chart)
and with accumulation, respectively;
ΔTt, ΔTA – difference of carrier temperature
between the supply and return pipeline in steady
mode and with accumulation, respectively;
К – correction factor, which takes into account
accumulation capacity of materials in the heating
networks.
Take G2 in the form
G2 = G1 +ΔG, (5)
where ΔG – increment in heat carrier consumption.
Substituting (5) to (4) and making the necessary
changes we get
Pa = KCρ[G1(ΔTA – ΔTt) + ΔGΔTA](1 – δ). (6)
It can be shown that
ΔTA – ΔTt = ΔT1– ΔT2 (7)
where ΔT1, ΔT2 – increments of carrier tempera-
ture in supply and return pipelines.
Substituting (7) to (6) we get
Pa = KCρ[G1(ΔT1– ΔT2) + ΔGΔTA](1 – δ). (8)
As the expressions (6) and (8) show the accumu-
lation of heat energy in the networks is possible only
by increasing the temperature of the carrier and/or
increasing its consumption.
Consider the process of heat energy accumula-
tion during heating and non-heating seasons.
During the heating season the DH systems use
quality control (heat carrier consumption is con-
stant, temperature changes in the supply pipeline).
Then the expression (6) takes the form
Pa = KCρG1(ΔTA – ΔTt)(1 – δ) (9)
The maximum possible power at heating net-
work input (potential) can be determined based on
the expression (9)
Pam = KCρGн(ΔTmax – ΔTt)(1 – δ), (10)
where Pam – the maximum power that can cause
the heat accumulation in the network (the maxi-
mum power of ETCC at discharge of heat energy
into the network);
Gн – regulatory heat carrier consumption;
ΔTmax = T1max – T2max = 80°C maximum differ-
ence of carrier temperature between the supply and
return pipelines for temperature chart 150/70°C;
T1max, T2max – maximum temperature in the
supply and return pipelines.
Function ΔTt = f(t°) is piecewise linear, thus the
function ΔTmax – ΔTt will also be piecewise linear.
This function can be present analytically using the
system of equation below, and its graph is shown in
Figure 1.
The graph shows that at the design temperature
–22°C the function value (ΔTmax – ΔTt) is zero.
Thus, the expression (10) at this point is zero. This
means that at ambient air temperature t° ≤ –22°C
the accumulation in the heat networks is impossi-
ble. This is explained by the fact that the parameters
of the heat carrier reached the maximum permissi-
ble values for the safe operation of the network, and
all energy compensate the heat load and losses.
Then, at increasing the ambient air temperature the
accumulation potential increases and reaches the
maximum value at the culminating point of temper-
ature graph +4°C.
For example, according to the formula (10), the
accumulation potential of heat energy in main pip-
ing networks of six sources in Kharkiv regional heat
supply system is defined, a summary of which is
presented in the Table 1.
Output data.
Temperature chart 150/70°C at the minimum
design temperature minus 23°C; К=1.09 (taken for
the average diameter of pipelines Dу= 400 mm);
С = 4.178 kJ/kg°C; ρ =958,05 kg/m3; δ=0,07 (loss
in main pipeline networks – 7%). The calculation
results are shown as graphs in Figure 2. The pattern
of the potential accumulation from temperature for
ΔTA = { 52,5, t ≥ 4°C
2.0192t + 44,4224, 4°C ≥ t ≥ –22°C
(11)
31ISSN 1562-8965. Проблеми загальної енергетики, 2014, вип. 4 (39)
Potential of thermal energy accumulation in distric heating systems networks
Figure 1. Function graph (ΔTmax – ΔTt)
Table 1 – Heating sources
all sources is similar to function ΔTA, which is
describe above.
During non-heating period the only load of
DH system is hot water supply, which operates
according the temperature chart 70/42°C. Heat
carrier consumption is 2–3 times smaller than
during heating season. Accumulation time of heat
energy in the networks coincides with time of min-
imum hot water distribution. In order to be within
the maximum heat carrier temperature in the
return pipeline (70°С), heat energy accumulation
must be done by increasing the heat carrier con-
sumption at constant temperature in the supply
pipeline. Based on (6) the expression for the max-
imum power, which causes accumulation, takes
the form
Pa = KCρ[ΔG ΔTA](1 – δ), (12)
where ΔTA = ΔTt = 28°C.
The accumulation potential during non-heating
season was calculated for six heat sources of
Kharkiv heat supply system. It was assumed that at
the beginning of the accumulation the heat carrier
flow was doubled. The calculation results are
shown in Table 2.
In actual use the accumulation potential can be
increased by 20-25% at the expanse of increasing
temperature in the supply pipe up to 84-87 °C (pro-
vided that the extreme temperatures will not be
increased in the return pipeline). Such capacity
increment designed to compensate heat losses in
the networks.
CONCLUSIONS
As a result the analytical expressions were
obtained that allow to define the accumulation
potential of heat energy in the networks and its
32 ISSN 1562-8965. Проблеми загальної енергетики, 2014, вип. 4 (39)
V.O. DERII
Figure 2. Dependency of accumulation potential on ambient air temperature
Table 2 – Accumulation potential during non-heating season
dependency on the ambient air temperature.
1. It was found that the accumulation poten-
tial is proportional to ambient air temperature.
2. It was shown that at air temperatures lower
than the minimum calculated one, heat accumula-
tion in the networks is impossible and ETCC can
operate only by replacing the energy of boiler house
heat generators.
3. During non-heating season the thermal
energy accumulation are limited due to the low heat
load.
1. Podobed V.S. Akkumulirovanie teplovoi
energii v vodianykh teplovykh
setiakh//Energeticheskaia strategia. – Minsk. –
2011. No.5(23).–22-26 s. (Rus.)
2. Podobed V.S. Akkumulirovanie teplovoi
energiivvodianykhteplovykhsetiakhvuslovi-
iakhotopitelnogoperioda//Energeticheskaia
strategia. – Minsk. – 2011. No.6(24).–16-18 s.
(Rus.)
3. Derii V.O. Tekhnichni ta instytutsiini fak-
tory vprovadzhennia spozhyvachiv-reguliatoriv
u systemakh tsentralizovanoho teplopostachan-
nia//Problemy zahalnoi enerhetyky. No.2(37).
– Kyiv. – 2014. (Ukr.)
4. Fizicheskiie svoistva vody. Rezhym dostupu
http://www.teplomontag.net/arhiv/text.php?ru
brika=3&text=13&stranica=0
Submitted to the editorial board 30.10.2014
33ISSN 1562-8965. Проблеми загальної енергетики, 2014, вип. 4 (39)
Potential of thermal energy accumulation in distric heating systems networks
|
| id | systemreorg-article-535 |
| institution | System Research in Energy |
| keywords_txt_mv | keywords |
| language | Ukrainian |
| last_indexed | 2026-07-19T01:17:10Z |
| publishDate | 2014 |
| publisher | General Energy Institute of the National Academy of Sciences of Ukraine |
| record_format | ojs |
| resource_txt_mv | systemreorg/93/8667130da9b163d8281999913ef3d193.pdf |
| spelling | systemreorg-article-5352026-07-18T12:57:41Z Potential of thermal energy accumulation in distric heating systems networks Потенціал акумуляції теплової енергії в мережах Derii V.O. heating networks, accumulation, heat load, temperature chart, heating power, heat carrier consumption, heat carrier temperature, potential. теплові мережі, акумуляція, теплове навантаження, температурний графік, теплова потужність, витрати теплоносія, температура теплоносія, потенціал. When using the electrothermal consumers-controllers (ETCC) in distric heating (DH) systems for frequency control, and for active power it is important to know their power during the heating and non-heating seasons and dependency of such power on the ambient temperature. Currently these issues are not studied completely that can be an obstacle to mass adoption of ETCC in DH systems.Total capacity of standard heat generators and ETCC transferred to the networks is distributed as follows: one part of it is designed to compensate the losses, the second part – to compensate heat load of consumers, and the third part causes the heat energy accumulation, which circulates in the networks.The conducted studies have shown that during the heating season the value of accumulated heat in the networks is directly proportional to the ambient air temperature. This dependency is expressed by a piecewise linear function. When ambient air temperature is smaller than calculated one, accumulation in heat networks is impossible. This can be explained by the fact that the parameters of the heat carrier reached the maximum permissible values for safety operation of the network, all energy in the network compensates the heat load and losses. When increasing ambient air temperature, the accumulation potential increases reaching a maximum value at the culminating point of the temperature chart.During non-heating season the only load of DH system is hot water. Heat carrier consumption is 2-3 times smaller than during the heating season. Heat energy accumulation time in the networks coincides with time of minimum hot water distribution. In order to be within the maximum heat carrier temperature in the return pipeline, heat energy can be accumulated at the expanse of increasing the heat carrier consumption at constant temperature in the supply pipeline. The value of accumulated heat energy will be much lower than during the heating season. При використанні електротеплових споживачів-регуляторів (ЕТСР) в системах централізованого теплопостачання для регулювання частоти та активної потужності важливо знати, яка може бути їх потужність в опалювальний та міжопалювальний періоди та як ця потужність залежить від температури навколишнього повітря. На даний час ці питання недостатньо вивчені, що може бути перешкодою для масового впровадження ЕТСР в централізованих системах теплопостачання.Сумарна потужність штатних теплогенераторів та ЕТСР, яка підводиться до мереж, розподіляється таким чином: частина її іде на компенсацію втрат, частина на покриття теплового навантаження споживачів, а частина спричиняє акумуляцію теплової енергії, яка циркулює в мережах.Проведені дослідження показали, що в опалювальний період величина акумульованої теплової енергії в мережах прямо пропорційно залежить від температури навколишнього повітря. Ця залежність виражається кусочно-лінійною функцією. При температурах навколишнього повітря менших за розрахункову, акумуляція в теплових мережах неможлива. Цей факт пояснюється тим, що параметри теплоносія досягли максимально допустимих значень для безпечної роботи мережі і вся енергія в мережі іде на покриття теплового навантаження та компенсації втрат. Із збільшенням температури навколишнього повітря потенціал акумуляції зростає досягаючи максимуму в точці злому температурного графіка.В міжопалювальний період єдиним навантаженням системи теплопостачання є гаряча вода. Витрати теплоносія в 2–3 рази менші, ніж в опалювальний сезон. Час акумуляції теплової енергії в мережах збігається з часом мінімального водорозбору гарячої води. Щоб не перевищити максимальну температуру теплоносія у зворотному трубопроводі, акумулювати теплову енергію можливо за рахунок збільшення витрат теплоносія при незмінній його температурі у подавальному трубопроводі. Величина акумульованої теплової енергії буде значно меншою, ніж в опалювальний період. General Energy Institute of the National Academy of Sciences of Ukraine 2014-11-27 Article Article application/pdf https://systemre.org/index.php/journal/article/view/535 System Research in Energy; No. 4 (39) (2014): The Problems of General Energy; 29-33 Системні дослідження в енергетиці; № 4 (39) (2014): Проблеми загальної енергетики; 29-33 2786-7102 2786-7633 uk https://systemre.org/index.php/journal/article/view/535/471 Copyright (c) 2014 Derii V.O. https://creativecommons.org/publicdomain/zero/1.0 |
| spellingShingle | heating networks accumulation heat load temperature chart heating power heat carrier consumption heat carrier temperature potential. Derii V.O. Potential of thermal energy accumulation in distric heating systems networks |
| title | Potential of thermal energy accumulation in distric heating systems networks |
| title_alt | Потенціал акумуляції теплової енергії в мережах |
| title_full | Potential of thermal energy accumulation in distric heating systems networks |
| title_fullStr | Potential of thermal energy accumulation in distric heating systems networks |
| title_full_unstemmed | Potential of thermal energy accumulation in distric heating systems networks |
| title_short | Potential of thermal energy accumulation in distric heating systems networks |
| title_sort | potential of thermal energy accumulation in distric heating systems networks |
| topic | heating networks accumulation heat load temperature chart heating power heat carrier consumption heat carrier temperature potential. |
| topic_facet | heating networks accumulation heat load temperature chart heating power heat carrier consumption heat carrier temperature potential. теплові мережі акумуляція теплове навантаження температурний графік теплова потужність витрати теплоносія температура теплоносія потенціал. |
| url | https://systemre.org/index.php/journal/article/view/535 |
| work_keys_str_mv | AT deriivo potentialofthermalenergyaccumulationindistricheatingsystemsnetworks AT deriivo potencíalakumulâcííteplovoíenergíívmerežah |