Determination of the Number of Heat Generators of an Independent
Heat Supply Source When Planning the Development of the Urban
Environment
Dmitry Kitaev
a
, Svetlana G. Tulskaya
b
and Galina N. Martynenko
c
Voronezh State Technical University, Voronezh, Russia
Keywords: Development of the Urban Environment, Heat Supply, Heat Generator, Coolest Month Mode, Heating, Hot
Water Supply, Number of Heat Generators
Abstract: The article concentrates on the selection of the number of boilers in boiler houses of independent heat supply
sources. The analysis of the current standards to justify the selection of the number of boilers is carried out.
For settlements, presented in the latest revision of climatological data, the values of the heat consumption
reduction coefficient for heating needs in the cold month mode were obtained, the possible range of its change
was established. Using the example of a low power boiler house, a significant influence of the climatic data
of the cold month on the number of heat generators is shown. Based on the established range of variation of
the heat consumption reduction coefficient, the ratio of heat consumption for heating and hot water supply for
multi-apartment residential buildings with independent heat supply sources, the range of the possible number
of boilers was established. The ranges of the heat consumption reduction coefficient for heating needs have
been found, which make it possible to nearly determine the corresponding number of required heat generators.
1 INTRODUCTION
The heat supply system is part of the engineering
infrastructure of cities. The sustainable development
of city development is closely related to the
development of the heat supply system. When
planning general plans of cities, it is necessarily to
take into account the development of generating
capacities and the system of transporting heat energy.
The federal law on heat supply in the Russian
Federation obliged each settlement to develop and
approve heat supply schemes, that determine the
development of the entire system as a whole, and also
update them annually. Often the planning horizon of
the city general plan and the heat supply scheme
coincide, i.e. their development is synchronous. In
addition, the heat supply scheme during development
is linked to the water supply and gas supply schemes.
The approach to sustainable development of
territories and engineering infrastructure should be
complex (Kitaev, 2010; Semenov, 2010)
a
https://orcid.org/0000-0003-4148-1261
b
https://orcid.org/0000-0003-4822-4938
c
https://orcid.org/0000-0002-2133-6051
With the strategy of the sustainable development
of the heat supply system, it is necessary to determine
the possibility of connecting the promising city
development to the existing systems. The centralized
system does not always have the necessary capacity
reserves, and in some cases, the construction of long
underground networks with generation sources is not
economically feasible. In recent decades, there has
been an increase in the number of introduction of
independent heat supply sources in the housing and
utility services. In urban infrastructure, integrated
heat supply sources are widely used, represented by
built-in, attached and roof boiler houses (Semenov,
2011; Khavanov, 2005; Minin, 2016). Independent
heat supply is widely used to provide energy to high-
rise buildings in close city development, where it is
impossible to use underground centralized heating
pipelines (Gapeeva, 2018). The main advantage of
such systems is the ability to accurately regulate the
load of heat consumption systems, and the
disadvantages are noise and vibration impacts.
Beyond the scope of the article, we will drop the
Kitaev, D., Tulskaya, S. and Martynenko, G.
Determination of the Number of Heat Generators of an Independent Heat Supply Source When Planning the Development of the Urban Environment.
DOI: 10.5220/0010586801010106
In Proceedings of the International Scientific and Practical Conference on Sustainable Development of Regional Infrastructure (ISSDRI 2021), pages 101-106
ISBN: 978-989-758-519-7
Copyright
c
2021 by SCITEPRESS Science and Technology Publications, Lda. All rights reserved
101
subject of the need for a decentralized approach to
heat supply, its disadvantages and advantages over
the priority direction of the development of
centralized heat supply in the Russian Federation. In
recent years, along with centralized, independent heat
supply has been widely developing, this is a reality of
our time (Kitaev, 2010; Melnikov,2015).
Determining the number of boilers, installed in
boiler houses, is an important stage in the design of a
heat supply system (Martynenko, 2018; Semenov,
2015). The reliability of heat supply, operating costs,
and the cost of heat generation depend on the correct
selection. The selection of the number of boilers is a
multivariate task, that often requires creative
approach. The number of installed boilers in the
boiler house is influenced by many factors, such as
the consumer reliability category, climatic data of the
design area, the value of the design heat currents for
heating, ventilation, hot water supply and technology,
the value of the boiler house's needs, the minimum
value of the heat load of the heat generator itself
(Zbaraz, 2019; Panferov, 2020; Fang, 2015). Modern
standards in the field of heat supply recommend,
when determining the design capacity, to take into
account additionally the own needs of boiler houses
and waste of the heat energy during the transportation
of the heat carrier (in heating networks). The correct
value of the boiler house's own needs can be fulfilled
only after the end of the calculation and selection of
all equipment and pipelines, but even in this case,
some data, for example, on the number of boiler start-
ups, will have to be taken approximately. In addition,
in boiler houses of centralized sources, the values of
their own needs can reach 12-15% of the output,
especially in the case of using fuel oil and coal dust.
A similar situation is with waste of the heat energy in
networks, the actual values of which can reach 15-
20%. With a decrease in the capacity of the boiler
house, own needs and waste in the networks decrease,
especially when using gaseous fuel. In integrated heat
supply sources, their own needs are minimal, and
there are no networks.
Domestic and foreign authors pay great attention
to the issues of influence of the number of installed
boilers, modes of their load during the year on the
efficiency of the boiler house, and the heat supply
system as a whole. Measures are proposed to improve
the efficiency of existing heat supply sources (Kitaev,
2020; Chicherin, 2019; Terhan and Comakli, 2017).
2 RESEARCH METHODOLOGY
Modern design standards contain recommendations
for the selection of the required number of boilers.
Let's consider them in more detail. In the current SP
124.13330.2012 (Heating networks), it is
recommended in case of emergencies in the
centralized heating system during the entire repair-
recovery period to provide: supply of 100% of the
required heat to consumers of the first category
(unless other modes are provided for by the contract);
heat supply for heating and ventilation to housing and
utility and industrial consumers of the second and
third categories in the amount (depending on the
design temperature of the outside air from 78 to 91%);
consumer-specified emergency mode of steam and
process hot water consumption; consumer-specified
emergency heat mode of operation of non-
disconnectable ventilation systems; average daily
heat consumption for the heating period for hot water
supply (if it is impossible to turn it off).
SP.89.13330.2016 (Boiler-house plants)
recommends to select the number and capacity of
boilers, installed in the boiler house, providing: the
design capacity of the boiler house; stable operation
of boilers at the minimum permissible load during the
warm season. In case of failure of the boiler with
maximum output in the boiler houses of the first
category, the remaining boilers must provide heat
energy to consumers of the first category in an
amount determined by: the minimum permissible
loads (regardless of the outside air temperature) - for
technological heat consumption and ventilation
systems; mode of the coldest month - for heating and
hot water supply. In case of failure of one boiler,
regardless of the category of the boiler house, the
amount of heat, supplied to consumers of the second
and third categories, should be provided in certain
amounts (as in the SP Heating networks). It should be
noted, that these requirements do not apply to
independent heat supply sources, integrated into
buildings.
SP 373.1325800.2018 (Independent heat supply
sources) recommends, in the event of failure of the
boiler with maximum output, to provide heat with
remaining in operation for the following purposes:
technological heat supply of the ventilation system -
in an amount, determined by the minimum
permissible loads (regardless of the outside air
temperature); heating, ventilation and hot water
supply - in the amount, determined by the mode of the
coldest month.
From the above recommendations, it can be
concluded, that in the absence of a ventilation load
ISSDRI 2021 - International Scientific and Practical Conference on Sustainable Development of Regional Infrastructure
102
(usually multi-apartment residential buildings), the
requirements for independent heat supply sources and
other boiler houses of the first category are the same
in terms of reliability.
3 RESULTS
Putting aside the heat load for the ventilation system,
it is usually absent for a residential building, then
independent source need, in case of failure, to provide
a load of heating and hot water supply in the cold
month mode.
In this case, when determining the power value of
the boiler house when the largest boiler fails, it will
be necessary to evaluate the heat consumption
reduction coefficient for heating needs by the well-
known formula
0
i
х
м
i
tt
K
tt
.
To evaluate the coefficient K, the data of SP
131.13330.2018 (Construction climatology) were
analyzed for the presented settlements (467
settlements). For the majority of the territory of the
Russian Federation (except for two settlements), the
coldest month is January. Table 1 presents climatic
data and the value of the coefficient K for a sample of
51 settlements, that are regional capitals.
Table 1: Values of the heat consumption reduction coefficient.
Settlement K Settlement K Settlement K
Krasnoyarsk 0.618 Maykop 0.517 Yakutsk 0.817
Sevastopol 0.514 Blagoveshchensk 0.790 Yekaterinburg 0.634
St. Petersburg 0.586 Arkhangelsk 0.620 Vladikavkaz 0.674
Magadan 0.748 Astrakhan 0.585 Smolensk 0.593
Yoshkar-Ola 0.590 Ufa 0.624 Stavropol 0.581
Saransk 0.592 Ulan-Ude 0.787 Kazan 0.604
Moscow 0.600 Vladimir 0.616 Tomsk 0.633
Murmansk 0.594 Vologda 0.594 Kyzyl 0.728
Naryan-Mar 0.633 Makhachkala 0.561 Tyumen 0.643
Nizhny Novgorod 0.585 Chita 0.791 Ulyanovsk 0.559
Novosibirsk 0.649 Irkutsk 0.714 Khabarovsk 0.815
Orenburg 0.618 Nalchik 0.578 Abakan 0.665
Perm 0.604 Kaliningrad 0.546 Chelyabinsk 0.660
Vladivostok 0.765 Sochi 0.600 Grozny 0.577
Pskov 0.552 Cherkessk 0.581 Cheboksary 0.620
Saratov 0.621 Vorkuta 0.649 Anadyr 0.686
Rostov-on-Don 0.589 Petropavlovsk-Kamchatsky 0.692 Yuzhno-Sakhalinsk 0.790
Fig. 1. shows the values of the coefficient K for
all settlements
Figure 1: Values of the coefficient K.
From these calculations, it follows, that the
minimum value of the coefficient K = 0.5 is observed
for Klepnino (Rep. Of Crimea), and the maximum for
the rural settlement of Kalakan is K = 0.949. The
maximum value is an exception and is observed only
for one settlement, moreover, with a small population
and consisting of individual residential development.
Putting aside the value of 0.949, then the following
will be K = 0.863 for Zavitinsk, Amur Region.
It follows from the calculations, that the load of
heating and ventilation systems in the coldest month
mode can range from 0.5 to 0.863 of the design one.
Consider an example of determining the number
of heat generators with the following initial data:
maximum heating load
max
o
Q
= 3.4 MW; average load
of hot water supply during the heating period
з
гвс
Q
=
0.96 MW, in non-heating period
л
гвс
Q
= 0.768 MW;
own needs of the boiler house are 1%. Taking into
Determination of the Number of Heat Generators of an Independent Heat Supply Source When Planning the Development of the Urban
Environment
103
account the initial data, the design capacity of the
boiler house in the heating period will be
з
р
Q
= 4.4
MW.
Table 2 shows the results of calculating the
number of boilers, that meet the requirements for
ensuring the load of heating and hot water supply in
the event of the failure of the largest boiler, for
various values of the coefficient K. Boilers of the
KVa type with a unit capacity of N1 1, 1.25, 1.6, 2,
2.5 MW were considered. In table N1 is the result of
dividing
з
р
Q
by the number of boilers. The last
column shows the load values in the summer period
∆,%. The minimum value for the type of boiler under
consideration is 40%.
Table 2: Number of boilers.
Coefficient
K
N
1
,
MW
N
1
,
MW
N
umber of
boilers n,
p
cs
∆,%
0.5 1.468 1.6 3 48
0.6 1.468 1.6 3 48
0.7 1.101 1.25 4 61.4
0.8 1.101 1.25 4 61.4
0.863 0.881 1 5 76.8
As can be seen from Table 2, climatic data have a
significant impact on the number of boilers. In the
example considered, the number of boilers is from
three to five. The minimum number of boilers, that
meet the requirement of standards, is three.
The heat load of the hot water supply system does
not depend on the outside temperature, therefore, for
the coldest month mode, the heat supply is
determined by the formula
max max
(0,5 0,863)
з
з
м o гвс o гвс
QQKQ Q Q
. (1)
4 DISCUSSION OF RESULTS
Consider the range of ratios of the maximum heat
consumption for hot water supply and heating 0.2≤
max
гвс
Q
/
max
o
Q
≤1, used in a number of standards (SP 41-
101-95 "Designing heat points", STO NP "RT"
70264433-5-1-2009 "Recommendations on the
design of heat points, located in buildings"). This
range of load ratios is predominant for residential
buildings (Zbaraz, 2019; Panferov, 2020; On the
analysis, 2017). Taking into account the ratio between
the maximum and average heat consumption for hot
water supply 2.4, given in SP 373.1325800.2018
"Independent heat supply sources", we obtain the
range 0.083≤
ср
гвс
Q
/
max
o
Q
≤0.417. Therefore, the
value of the average consumption for hot water
supply is in the range of 0.083
max
o
Q
ср
гвс
Q
≤0.417
max
o
Q
. Substituting the minimum and maximum
values of the ranges into expression (1), we get:
max max max
0,5 0,083 0,583
хм o оо
QQ Q Q
;
max max max
0,863 0,4167 1,28
хм o оо
QQ QQ
As a result, without taking into account own needs,
we obtain the possible range of heat load for the cold
month
0.583
max
o
Q
х
м
Q
≤1.28
max
o
Q
. (2)
The algorithm for selecting the number of boilers
is shown in Figure 2 and contains the following
stages.
Figure 2: Block scheme of determining the number of
boilers.
1. Based on the known load of the heating period,
the maximum and minimum value of the load of the
hot water supply and the boiler house is determined.
In accordance with the accepted restraints, the design
capacity of the boiler house can be in the range of
1.083
max
o
Q
кот
Q
≤1.4167
max
o
Q
. (3)
2. The unit capacity (of one boiler) of the boiler
N1, installed in the boiler house, is determined by
dividing the design capacity by the number of boilers
n. In the initial approximation, the minimum
allowable is taken, equal to two.
3. According to the catalog of boilers, we select a
boiler with a capacity of Ncat equal or greater than
the design N1. We install identical boilers of equal
capacity, as people try to do in practice.
ISSDRI 2021 - International Scientific and Practical Conference on Sustainable Development of Regional Infrastructure
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4. In order to fulfill the condition of providing the
calculated load of heating and hot water supply in
case of failure of the boiler with maximum output in
the cold month mode, we evaluate the value of the
load Qхм.
5. Check the fulfillment of the inequation N1 (n-
1) Qхм. If it is valid, then proceed to checking the
fulfillment of the requirement for the minimum boiler
load during the heating period (see cl. 6). If the
inequation is not valid, then go to step 2 and set more
boilers (n + 1), repeat the calculation until the
inequation is valid.
6. We check the fulfillment of the requirement to
provide the minimum boiler load in the non-heating
period
min
N
, when only the hot water supply system
is operating:
л
гвс
Q
/ N1≥
min
N
. If the inequation is
valid, then we print the number of boilers, if not, then
we increase the number of boilers (Cl. 2).
We use the algorithm considered to find the
maximum and minimum number of boilers, installed
in an integrated heat supply source.
Let's introduce additional restraints. We assume,
that according to the catalog of boiler designs, it will
be possible to select a boiler with a capacity Ncat
equal to the design N1. We assume, that it is possible
to select a boiler with an acceptable percentage of
load for the summer period. This will be facilitated by
the minimum value of boilers in the boiler houses of
the housing and utilities services, equal to two, and
the fact, that with an increase in the number of boilers,
the percentage of the minimum load in the summer
period of one boiler increases.
The requirement to provide the design load for the
cold month, when the boiler with maximum output
fails (with the same capacity of the boilers) is
determined by the inequation
1
кот хм
n
QQ
n
.
(4)
The minimum number of boilers is determined by
the expression
1
1
хм
кот
Q
n
Q




.
(5)
Taking into account expressions (2), (3), we
evaluate the values of the minimum and maximum
number of boilers, rounded to integers: nmin =
1.699≈2; nmax = 10.36≈11.
Using expressions (1), (2), (5), taking into account
the inequation 0.083
max
o
Q
ср
гвс
Q
≤0.417
max
o
Q
, the
values of the ranges of the coefficient K for the
corresponding number of boilers, presented in Table
3, were evaluated.
Table 3: Ranges of the heat consumption reduction
coefficient for heating needs for the corresponding number
of boilers.
n 2 3,4,5,6 7 8 9 10 11
K
min
0.5 0.5 0.511 0.531 0.546 0.558 0.568
K
max
0.63 0.861 0.863 0.863 0.863 0.863 0.863
From table 2 it follows, that two boilers cannot be
installed in the range 0.63 < K < 0.863, 3-6 boilers at
0.861 < K, 7 boilers at 0.5 < K < 0.511, 8 boilers at
0.5 < K < 0.531, etc. The determining factor is the
ratio of heat loads for heating and hot water supply.
5 CONCLUSIONS
The analysis of the standard literature allowed to
establish the requirements for providing minimum
consumer loads, affecting the determination of the
number of heat generators. On the basis of modern
climatic data, it has been established established, that
the value of the heat consumption reduction
coefficient for heating needs in the cold month mode
can have a value from 0.5 to 0.863. Taking into
account the data on the ratio of heat consumption for
hot water supply and heating, it was established, that
the number of boilers can be in the range from 2 to
11. The ranges of the heat consumption reduction
coefficient for heating needs are evaluated for the
corresponding number of boilers. The conclusions
obtained are also valid for boiler houses of centralized
heat supply systems of the first category of reliability
in the presence of heating and hot water supply loads.
The results obtained can be used in planning the
development of independent heat supply sources for
urban infrastructure.
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