International Journal of Mechanical Engineering and Technology (IJMET)
Volume 10, Issue 04, April 2019, pp. 54-64. Article ID: IJMET_10_04_008
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=4
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
© IAEME Publication Scopus Indexed
Eduard V. Kustrikov
Saint-Petersburg Mining University, Vasilyevsky Island, 21st line 2, 199106, Saint-
Petersburg,
ABSTRACT
Geothermal energy, which is related to alternative energy resources, is one of the fast-developing world energy resources. It is used both in Russia and other countries.
Nowadays problems of energy saving and economical use of fuel are paid much attention, which proves relevance of the topic. Goal of the research is an analysis of economical efficiency of geothermal energy use in North-West region of Russia using an example of heat pumps. Authors considered expediency of Earth’s geothermal energy use in North-West district using an example of European states. Analysis of specific factors characterizing this type of energy, as well as its extraction and used technology is done. Scientific, technical and technological problems of geothermal energy are reviewed.
Keywords: geothermal energy, heat pumps, alternative energy, European Heat Pump
Association (EHPA), renewable energy sources, refrigerant, sustainable.
Cite this Article Eduard V. Kustrikov, Perspective of Geothermal Earth Enegry Use in
North-West District of Russia, International Journal of Mechanical Engineering and
Technology, 10(4), 2019, pp. 54-64. http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=4
Nowadays, despite the fact that humanity has great power, it depends on the resources that nature gives us [Golovina, Chvileva, 2017]. Geothermal energy is produced in the depths of
Earth and comes to the surface in various forms and with different intensities. Geothermal energy is a kind of exotic resource, which in the current state of affairs is unlikely to compete with oil and gas. Nevertheless, this alternative form of energy can be used almost everywhere and quite efficiently.
According to the experts evaluation, it is estimated that today around 3.5% of the global geothermal potential is used to generate electricity and only 0.2% to generate heat. Recent years have been characterized by a sharp increase in the volume and expansion of geothermal resources. In the energy balance of a number of countries, geothermal energy technologies are
http://www.iaeme.com/IJMET/index.asp 54 editor@iaeme.com

Perspective of Geothermal Earth Energy Use in North-West District of Russia becoming dominant, and the share of geothermal energy in the global energy balance is steadily increasing.
Depending on the temperature, geothermal resources are widely used in electrical power engineering and heating, industry, agriculture, balneology and other areas (Table 1).
Table 1 Geothermal Heat Uses
Field of utilization
Energy:
- single-circuit geothermal power plant
- binary geothermal power plant
Industry:
- metallurgical industry
- paper production
- extraction of chemical elements
- oil industry
- production of concrete blocks
- textile industry
- wood industry
Agriculture:
- breeding fish
- ground heating
- growing vegetables and fruits
- food industry
- greenhouses
Heating:
- heat pumps
- air conditioning
- local heat supply
- radiators
- sidewalk heating
Balneology:
- swimming pools
- mud baths
Temperature interval of the heat carrier, °С
130-300
90-200
90-140
90-120
80-105
70-85
70-80
50-80
45-90
5-45
5-45
20-65
35-90
35-90
5-55
25-50
50-85
50-95
40-80
20-50
25-50
The world leaders in terms of installed thermal capacity of geothermal systems are the USA
- 7817, Sweden - 3840, China - 3687, Iceland - 1791, Turkey - 1177.
In recent years, geothermal heating systems based on heat pumps have been actively developing. In such systems, low-potential (temperature up to 55 º C) thermal water and petrothermal energy of the upper layers of the earth's crust are used as the primary source of heat. When using ground heat, heat-exchange units are used, they are placed either in vertical wells up to 300 m deep or horizontally at a certain depth.
In the USA, 69% of the total direct use of geothermal resources is based on the use of heat pumps. In 2004, approximately 60,000 heat pumps were installed. In Germany, the total heat output of geothermal systems is 505 MW, 400 MW of which is based on the use of heat pumps.
Due to the transfer of economy to geothermal resources, Iceland has become a developed country with a high standard of living. More than 87% of heat supply in Iceland is provided by geothermal heat, and in the near future it is planned to increase to 92%. An example of the http://www.iaeme.com/IJMET/index.asp 55 editor@iaeme.com

Eduard V. Kustrikov successful implementation of a large project is the creation of a geothermal heat supply system in Reykjavik, which provides about 99% of the heat demand. This system consumes 2348 l/s of geothermal hot water with a temperature of 86–127º C (Figure 1).
Figure 1.
Schematic diagram of the organization of heat supply in Reykjavik
1 – geothermal production wells; 2 – deaerator ; 3 – pumping station; 4 – emergency tanks ; 5 – peak boiler-room; 6 -– heat consumer.
The highest level of direct use of geothermal energy in recent years has been noticed in
China, Iceland, the United States and Turkey, the total amount of which is more than 54% of the world volume. A significant increase in the use of low-potential geothermal energy, as a result of the introduction of geothermal heat pumps, was achieved in Austria, Canada,
Switzerland and Sweden.
Production of geothermal energy can also be combined with extraction of groundwater, which is a commonly used, widespread and shared mineral resource [Golovina, 2019].
Groundwaters are extracted from aquifers and used for drinking and household purposes, in agriculture and production [Golovina, 2018].
Geothermal electricity generation is a proven technology that’s been around for over a century
(the first commercial geothermal power plant came on line at Larderello in Italy in 1911). The problem is that huge areas of the world simply don’t have the high-temperature resources necessary to support electricity generation. Figure 2 below [Bertani, 2015] shows Russia and
China with only 109MW of installed capacity between them. Tiny El Salvador, however, has almost twice as much, and as a result El Salvador gets 25% of its electricity from geothermal
(and other countries even more – the Philippines gets 27%, Iceland 30% and Kenya 51%) while
Russia and China get 0%. But only small countries can “go geothermal” in this way. None of the three large countries with relatively abundant geothermal resources presently fills more than a small fraction of its electricity demand with geothermal energy (Italy fills 1.5%, the US 0.3% and Japan only 0.1%). http://www.iaeme.com/IJMET/index.asp 56 editor@iaeme.com

Perspective of Geothermal Earth Energy Use in North-West District of Russia
Figure 2.
2015 world installed geothermal capacity by country
Russia has not only large reserves of fossil fuels, but also geothermal resources, the energy of which exceeds the entire potential of fossil fuels by an order of magnitude. Using the heat of the Earth in Russia can be up to 10% in the total balance of heat supply. 66 geothermal deposits with a capacity of more than 240 thousand m
3
/ day of thermal water and more than 105 thousand tons / day of steam hydrotherm have been explored in Russia. Over 4,000 wells are drilled to use geothermal resources.
The most promising for development of geothermal energy are the Kamchatka-Kuril, West
Siberian and North Caucasus regions. In Kamchatka, the Kuril Islands and the North Caucasus, geothermal electricity and heat supply can make up to 50–95% of the total energy consumption.
In the North Caucasus, geothermal deposits occurring at depths from 300 to 5000 m are well studied. The temperature in deep reservoirs reaches 180 º C and more. These fields are capable of generating up to 10,000 thermal and 200 MW of electrical power. The energy potential of artesian wells drilled into low-grade waters in the plains and seaside zones of Dagestan is estimated at around 1,500 thousand tons. t., which is almost 3 times higher than the needs of heat supply.
The low level of field exploitation and the huge difference between significant reserves of geothermal energy and its small part used is due to some specific factors characterizing this energy, as well as its extraction and used technology. These factors are:
• high cost of wells and low transportable qualities of thermal waters;
• the need for re-injection of wastewater and significant costs for their preparation;
• impossibility of accumulating thermal energy for a long period;
• corrosive properties characterizing thermal waters at great depths;
•
Disposable use of thermal waters in the heating system and their relatively low temperature, etc.
In this regard, there are scientific, technical and technological problems of geothermal energy, the main of which are:
• development of technologies for construction of high-production wells with horizontal wells in the productive horizon; http://www.iaeme.com/IJMET/index.asp 57 editor@iaeme.com

Eduard V. Kustrikov
• transfer of a significant number of inactive wells in the developed oil and gas fields to produce geothermal fluid;
• widespread adoption of geothermal circulation systems (GCC) technology;
• development of effective methods to combat corrosion and scaling;
• development of dual-circuit geothermal power systems based on low-cost corrosionresistant heat exchangers and serial production of modular equipment for the construction of single-loop and binary geoPPs;
• development of efficient integrated technologies for utilization of geothermal and related types of energy and hydro-mineral resources;
•
Development of efficient technologies for utilization of low-grade geothermal heat.
Practical implementation of these problems will dramatically increase the impact of existing geothermal production and solve significant energy problems associated with replacement of traditional organic fuels and provision of industry with mineral resources.
Environmental benefits of the use of renewable energy resources such as geothermal is recognized by few decision makers. Moreover, there are major barriers to the development of renewable resources which tend to discourage those few. Detailed geological investigations and expensive drilling of geothermal wells represent a major financial commitment with considerable geological and technical risks.
Despite problems of geothermal energy that are shown above, there are great advantages of this resource. The use of renewable energy, including geothermal resources, denote benefits.
First, use of indigenous energy resources can reduce some of the import dependence or part of the need to build new generating capacity for either supply of heat or industrial or residential hot water supply. Secondly, replacement of conventional fuels with clean energy induces major improvements in environmental conditions and public health and associated savings. Thirdly, a measure of energy savings an efficiency is involved [Nikulin, Nikulina, 2017]. As district heating systems are common in urban centers of Russia and are in need of modernization, switching to renewable energy resources could take advantage of these benefits. This is particularly important from the economic perspective also; the antiquated district heating systems are not fuel efficient and the engineering life time of most have already expired
[Svalova, 2011].
Areas of application and efficiency of using geothermal waters depend on their energy potential, total reserve and well flow, chemical composition, salinity, water aggressiveness, availability of the consumer, its distance and some other factors.
The most effective area of application of geothermal waters is heating, hot and technical water supply for various facilities. The maximum energy effect is achieved by creating special heating systems with a high temperature difference.
Under the conditions of housing and communal services reforming, local heat supply systems based on advanced technologies are most effective. Practically in all regions of Russia there are significant reserves of low-potential thermal waters, which can be successfully used in heat supply systems with heat pumps.
From accumulated in recent decades, the experience of the development of thermal energy of the Earth’s subsoil, it follows that hydrogeothermal resources are successfully mastered in many countries around the world for the production of electricity and heat, while meeting the most diverse needs of human activities. The use of geothermal energy is constantly growing, the number of countries successfully using this energy is also increasing every year [Andrews,
2015]. http://www.iaeme.com/IJMET/index.asp 58 editor@iaeme.com

Perspective of Geothermal Earth Energy Use in North-West District of Russia
Geothermal resources are a practically inexhaustible, renewable and environmentally friendly source of energy that will play a significant role in the energy of the future.
The use of geothermal sources in Russia is a fairly promising area of renewable energy due to the low cost of energy they produce. The potential of geothermal sources of Russia far exceeds the reserves of fossil fuels (according to some sources, 10-15 times). Currently identified reserves of geothermal waters in Russia with a temperature of 40–200 ° C and a depth of up to
3,500 m can provide about 14 million m 3 of hot water per day, which is about 30 million tonnes of fuel equivalent.
The first geothermal power plant in Russia was built in 1966 at the Pauzhetskoye field in
Kamchatka to supply electricity to surrounding villages and fish processing enterprises.
Moreover, according to experts, it was thanks to the use of geothermal sources that the
Ozernovsky fish factory was able to maintain profitability in difficult economic conditions. At present, the Kamchatka geothermal system can provide power to a power plant with a capacity of up to 250-350 MW. However, this potential is used only by a quarter.
Geothermal resources of the Kuril Islands currently produce 230 MW of electricity, which can provide all the needs of the region for energy, heat and hot water.
The most promising regions for the use of geothermal sources in Russia are the south of
Russia and the Far East. The Caucasus, the Stavropol Region, and the Krasnodar Territory have a huge potential for geothermal energy. Here, at almost any point, it is possible to begin the development of geothermal waters with temperatures ranging from 70 to 126 °C. Moreover, water comes to the surface under natural pressure, which significantly reduces the cost of pumps. Currently, 30% of the housing stock in Dagestan is heated and supplied with water due to geothermal sources. This indicator even in modern conditions can be increased to 70%.
In the Kaliningrad region, a geothermal field with a temperature of 105-120 °C was detected, which can be used to generate electricity.
The use of geothermal waters in the central part of Russia is costly due to the deep occurrence of thermal waters - below 2 km. In these regions, promising and beneficial for heat supply is the use of geothermal waters with a temperature of 40-600°C, located at a depth of
800 m, as well as the use of ground heat through heat pumps. This practice has not yet been widely used in Russia and is used in a number of individual projects: a 17-storey building in
Moscow, a school in the Yaroslavl region, and individual cottage villages.
Geothermal power engineering of Russia is focused both on the construction of "giants"
(large objects) and on the use of geothermal energy for individual houses, schools, hospitals, private shops and other facilities with a capacity of 0.1-0.4 MW using geothermal circulation systems.
At present, about 50 geothermal deposits have been explored in Russia. For the further development of geothermal energy, investment and state support are needed. The introduction of geothermal energy into the energy balance of the country will, on the one hand, improve energy security, and on the other, reduce the harmful effects on the ecological situation in comparison with traditional sources.
For the development of geothermal heat, heat pumps are used. Hot water and steam are used to generate electricity and for heating directly, and heat concentrated deep in the absence of water is converted into a useful form by heat pumps. The energy of magma and the heat that accumulates under volcanoes are extracted in similar ways.
A heat pump uses renewable energy — heated air, land, rock, or water — to produce heat.
This conversion is carried out with the help of special substances - refrigerants. The number of http://www.iaeme.com/IJMET/index.asp 59 editor@iaeme.com

Eduard V. Kustrikov installed heat pumps in Europe in December 2017 beat 10 million. In Russia, according to the most courageous estimates, we are talking about several thousand pieces of equipment, although the market is saturated with various systems of European, American, Chinese manufacturers. The main factors hindering the growth of the heat pump market are the relatively low cost of operating gas main equipment, the lack of support programs and subsidizing the end user of heat pump equipment. Also, there is a small awareness of potential consumers and some distrust of these systems.
The European Heat Pump Association (EHPA) represents the majority of the European heat pump industry. Its members comprise of heat pump and component manufacturers, research institutes, universities, testing labs and energy agencies. Its key goal is to promote awareness and proper deployment of heat pump technology in the European market for residential, commercial and industrial applications. EHPA aims to provide technical and economic input to
European, national and local authorities in legislative, regulatory and energy efficiency matters.
All activities are aimed at overcoming market barriers and dissemination of information in order to speed up market development of heat pumps for heating, cooling and hot water production.
EHPA presented data on sales of heat pump equipment in 2015, as part of the annual report
(Figure 3).
Figure 3.
Statistics of sales of heat pumps in Europe in 2005-2015
According to a published report, in 2015, the European heat pump market grew by 10% compared with 2014 data and continues to grow every year.
Consider heat pumps based on geothermal energy and most frequently used in the North-
West region of Russia:
The heat energy of the Sun is perceived by the soil, either directly in the form of radiation, or indirectly in the form of heat received from the rain or from the air. Heat accumulated by soil is taken either by vertical soil probes or horizontally laid soil collectors. Pumps of this type are also called geothermal heat pumps. The advantage is stability of work and the highest heat removal among all types of heat pumps. The disadvantage is the relatively high cost of drilling http://www.iaeme.com/IJMET/index.asp 60 editor@iaeme.com

Perspective of Geothermal Earth Energy Use in North-West District of Russia in the case of a geothermal heat pump and a large area to accommodate horizontal ground reservoirs (with a heat demand of about 10 kW and dry clay soil, the collector area must be at least 450 square meters). Power factor 3-5.
Groundwater is a good battery of solar thermal energy. Even in the winter period, the days they maintain a constant positive temperature (for example, for the North-West region, this indicator is at the level of + 5 + 7 ° С). However, in our opinion, the best prospects for application are heat pumps that run on heat from waste and process water. Continuous water flow, its high temperature level guarantee a constantly high power factor. For industrial enterprises, investing in a heat pump installation immediately, from the moment of launch, will provide savings on heating costs and reduce dependence on centralized heat supply networks. In this case, the heat discharged into the drains is, in fact, a source of additional income, which without the use of a heat pump would be impossible. The advantage is stability of work. The disadvantage is that a stable flow of water of satisfactory quality is necessary for stable operation. Power factor - 4-
6.
2.3.1. Economical.
In the absence of a gas pipeline, the cost of heating will be minimal. How high the economic efficiency of a heat pump will be depends on many factors: the source of heat energy, the price of electricity in your area, the cost of heat energy from different types of fuel, but remember that, in any case, the heat pump produces up to 1 kW 4 or more kW of heat energy.
2.3.2. The heat pump can be used in any terrain and in any climate.
Even if, for some reason, there is no electricity supply, it is possible to use a diesel or gasoline generator with a capacity of only 2-5 kW, and using a heat pump, build a full-fledged heating and hot water supply for houses up to 300 square meters
2.3.3. Ecological cleanliness.
Heat pumps do not emit harmful substances into the atmosphere, as they operate without burning fuel. Also during operation of heat pumps, prohibited refrigerants are not used.
2.3.4. Safety of use.
During the operation of heat pumps, no combustible and explosive substances, such as gas or diesel fuel, are used, therefore fires, explosions and leakages of harmful substances are excluded.
2.3.5. Durability and reliability.
Having reached a high level of structural strength, heat pumps can operate for 20-25 years without major repairs.
2.3.6. Takes place no more than a refrigerator.
Heat pumps require significantly less space than other types of heating. http://www.iaeme.com/IJMET/index.asp 61 editor@iaeme.com

Eduard V. Kustrikov
2.4.1. Price
For example, to heat a house with an area of about 80 m², to supply it with hot water and air conditioning in summer, you will need to purchase a unit with a capacity of at least 6 kW and a cost of 8–10 thousand euro, and also worry about mounting, which will involve the creation of 100-meter well, and, as you know, earthworks are expensive.
We also note that heat pumps fully justify themselves only in high-quality buildings, where heat losses are no more than 100 W / m². In other words, the warmer the house, the more profitable to use such equipment. Actually, this rule works with all types of heating.
2.4.2. The heat pump is not autonomous.
There is a dependence on electrical energy (see above stage 3 of the principle of operation of the heat pump).
It is believed that heat pumps are not good for all territories. There is an integral characteristic of D, which depends on climatic conditions.
The use of groundwater heat pump installations in the North-Western region of Russia takes place in geological and climatic conditions that differ significantly from the European average: below the soil temperature (for example, to a depth of 10 m, 4 ÷ 7 ° C instead of 10 ÷ 15 ° C),
1.5 ÷ 2.0 times the integral characteristics of the heating period.
Integral characteristics are usually used for a cumulative assessment of local climatic features that affect the resulting annual heat consumption of heated objects.
Quantitatively, the integral characteristics of the heating period are calculated by the formula:
D d
( t вн
t нар
)
T от
, where t вн
и t нар
is the average for the heating period temperatures of internal and external air, ° С; - the duration of the heating period, days
[Semenov, Solovyev, 2009].
According to these characteristics, you can judge the performance of the heat pump: the larger the number D in the territory, the less advantageous it is to install a heat pump there. d
For example, D d for Denmark is 2779.
The duration of the heating period according to St. Petersburg is 220 days, t вн is in the range of 20-22 ° C (GOST 30494-96), and t нар be calculated: D d
= −
1,8 o С . Thus, for the city of St. Petersburg,
= − −  =
5236 o С  сут .
D d
can
Consequently, for residential buildings in Denmark and Germany, the installation of a heat pump will be more cost-effective than for houses in Russia [6]. But, nevertheless, the experience of foreign countries with similar climatic conditions proves the feasibility of using heat pumps in the North-Western region of our country.
According to statistics, objects heated by heat pumps with an area of 50–200 m
2
have a payback period of about 7–9 years, objects with an area of 500 m
2
will pay off in 5–7 years,
700–1500 m
2
- in 3–4 years.
In the North-West region of the Russian Federation, the leading positions are occupied by ground-water and water-to-water heat pumps due to the low power in winter and high efficiency of air conditioning. Consumers are owners of private housing construction beyond the reach of central heating with a power limit of power and limited ability to connect main gas. http://www.iaeme.com/IJMET/index.asp 62 editor@iaeme.com

Perspective of Geothermal Earth Energy Use in North-West District of Russia
Several companies have been quite successful in the service market, which have proved the effectiveness of the use and use of heat pumps in the conditions of the North-West region, in particular, the Leningrad Region.
For example, TMEnergy specialists have developed more than 30 energy-efficient solutions ready for implementation for autonomous and safe heating of camps, sanatorium-andprophylactic buildings for the conditions of the Leningrad Region [Luneva, 2015].
In the near future, the price of gas, oil and other types of energy in the Russian Federation will increase, as indicated by the market situation, which will push more and more people to use alternative energy, including geothermal. Especialle it is vital in the context of sustainable development, which unites social, environmental and economic aspects of life in interests of present and future generations [Chvileva & Golovina, 2017].
Thus, the use of geothermal energy in the North-West region of Russia will not be a simple task, but it is an economically viable solution for people outside the city. Creating an efficient power infrastructure is key for the socio-economic development of the region [Kirsanova,
Lenkovets & Nikulina, 2018]. The doublet scheme will be the most effective scheme for the
North-West region, taking into account the low temperature gradient and hydrogeological features of the region, due to higher heat exchange.
The most frequent schemes of heat pumps in the North-West region (areal, double-circuit wells, doublet well systems). An additional advantage is the possibility of using the production well as a source of water supply for its own needs.
To sum up, the most effective scheme for the North-West region should take into account: a) Low temperature gradient; b) Hydrogeological features of the region, i.e. the presence of aquifers with high filtration parameters (Gdov aquifer (100-180 m) in the North and Ordovik (30-60 m) in the South). In this case, the preference for the doublet scheme, i.e. 2 wells are made, better heat transfer. c) The lack of gas supply in many residential areas, as well as the high cost of gas and electricity for individual households and residents. d) Improving the efficiency of heat pump systems based on advanced scientific research and technology.
At the same time, it is reasonable to determine the social and environmental potential based on the offered indicators [Cherepovitsyn, Romasheva & Chvileva, 2018].
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