IDL - International Digital Library Of Technology & Research Volume 1, Issue 5, May 2017
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International e-Journal For Technology And Research-2017
Geo-Thermal Heat Pump – Application Aspects in India SouravPandit 1,Dr. A Kundu2 Mechanical Engineering Department Jalpaiguri Government Engineering College Jalpaiguri 735102,India 1 sourav.mechanic@gmail.com 2 arijit.kundu@me.jgec.ac.in
Abstract:
Geo-Thermal Heat Pump or Ground Source Heat Pump or Ground Coupled Heat Pump is utilize a heat pump for Space Conditioning purpose by using the high enthalpy ground energy (use ground as heat sink in summer season or as heat source in winter season). They use earth as a heat exchange medium which can use source and sink vice versa. They convey heat from the ground to the evaporator of the heat pump in heating mode and they can also extract heat from room or space to the ground heat exchanger (GHE) in cooling mode. More than two decades of research work make GSHP a well-recognized concept for space conditioning, for its contribution on sustainable development on energy crisis and mitigation of environmental energy degradation. Huge energy consumption of India as a developing country make him as one of biggest energy importer and also a top ranked producer of greenhouse gases (GHGs)in the world. For sustainable growth of GDP in any country needs an uninterrupted supply of energy. The geographical position of India is responsible for its hot climate condition. So there are huge usage of space conditioning systems in domestic, commercial and in industrial sector. In India, all space heating and cooling is done with fossil fuels and air to air heat pumps, huge amount of energy is used for space conditioning purpose. There are huge potential of GSHP application in India to reduce its energy dependency over conventional energy sources for
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space conditioning purpose and also help India to reduce GHGs emission and leave a mark over global warming effects. This study deals with the review of GSHP and explorer the opportunity of its application in India with its benefit. Keywords: Geothermal Energy, Heat Pump, Sustainability, Space conditioning; Indian Space Conditioning, Ground: Heating; Cooling
1.
INTRODUCTION
Rising energy demand and enormous increasing global warming with increasing greenhouse gas in our environment, pushes us to find other energy resources over non-renewable energy sources. In now a day, our trend become, a shifting towards energy efficient renewable energy sources as compared to conventional energy sources with reducing GHGs emission. The use of geothermal heat pump for space cooling and heating purpose can reduce conventional energy consumption with reducing GHGs emission to the environment. As a developing country India consume huge energy resources for maintain its GDP and its steady growth. As a primary energy consumer India is after China and USA [1]. The electricity generation in India 70% dependent on fossil fuel. India is mainly dependent on import fossil fuel to meet its fossil fuel demand [1].
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International e-Journal For Technology And Research-2017 India also is in the top list of GHGs emitted country [2]. Due to the geographical position India has a warm climatic condition [3], for which there are extensive use of space conditioning systems and huge requirement of energy for this purpose. There geothermal heat pumps come as a solution of reducing energy usage for space conditioning and mitigation of environment degradation. A GCHPs extract heat from earth (utilize as heat source) in winter season and utilize as a heat sink in summer season as the temperature below the earth surface or ground remains nearly same throughout the year [4]. The large amount of radiated energy absorbed by earth and damped or restrained by the earth mass [5]. In the cooling mode a GCHP extract heat from the system or space and convey it to the ground heat exchanger (GHEs) and is taken out to the earth. In heating mode heat is extracted from ground and send it to the evaporator of heat pump. Generally earth is more thermally stable heat exchange medium with high heat carrying capacity than air, which is almost inexhaustible and easy available throughout the world. Many countries utilize geothermal energy resources, but those at low temperature those are frequently used in winter heating [6, 7]. In many countries GCHPs are used to cool the room temperature and reject heat in the ground. The use of earth energy reduces the use of fossil fuel and reduce of degradation of air quality. However ground source water is typically available at 35-50 ⁰ C directly, it is difficult to extract or utilize [6]. But in many developing countries GCHPs used frequently to solve environmental pollution problem and reduce the use of energy. As ground can exchange heat more efficiently then air so GCHPs run efficiently and reduce the energy usage. As a developing country, India is always a power hungry nation to maintain its growth [8] and also a top producer of CO2 gas [2]. So it will be very much popular of using GCHPs for space conditioning in place of conventional space conditioning systems. 2.
Ecological Concerns
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Geothermal energy resources are considered as renewable and ―green‖ [9]; however there are very few ecological encroachments those are affected our environment [10], but for the long run or by applying some extra arrangements can reduce these effects. These make the use of geothermal energy very popular now a days. Some gasses are discharged during the process of drilling or hot water extraction in geo thermal power plant, ex: CO2, SO2, N2O, H2S etc. But these can be easily converted in their elemental form, like H2S regularly processed at geothermal power plants and converted to elemental sulfur, which doesn’t affect environment [11]. The noise is produced commonly at a power plant or direct-use site during the well drilling process. Mostly noise comes only at the very first time only. The other sound comes from cooling fan and turbine section, which is not affect environment. Geothermal plant utilize 20 liters of fresh water for per MWh energy production in comparison generally a conventional coal plant takes 1,370 liters per MWh production; about 15% less is used in oil plant and about 25% more than coal plant is required by a nuclear power plant (www.cleanenergy.org). So huge savings of fresh usable water can be achieved by geothermal plant. There are also huge land area saving can be achieved. Increasing population density there are huge demand of environmental resources. So we need to use all these resource in optimize way. In same way reducing conventional practice for space conditioning can also reduce the environment pollution and starts the optimize use of energy. An analysis modeling results [12] to estimate the total equivalent warming impact (TEWI) of GCHPs in residential, commercial and institutional buildings can achieve reduction of CO2 emission from 15% to 77%. India is the fastest growing developing country in present day and 2nd populated country of the world next to china [13]. It is hold 17.86% of total world population. 32.8% of these population of India lives is in urban area. To maintain its development rate every country needs continuous supply of energy and to secure its growth and future generation it have to find
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IDL - International Digital Library Of Technology & Research Volume 1, Issue 5, May 2017
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International e-Journal For Technology And Research-2017 some sustainable energy supply. As a developing country India is in top position in GHGs emission. It is in top 4 position in GHGs emitted country [2]. As effect of this environment pollution there are many effects have already be seen. Due to geographical position Indian climate varies widely, most of its places are warm and many places are found cold in winter time [14]. So for better comfort there are huge application of space conditioning in residential, commercial and industrial purpose. Every year huge amount GHGs are emitted and also huge energy requirement, which mainly comes from fossil fuel burning. Increasing the use of GCHPs can decrease the energy requirement and emission of GHGs. It can help to increase air quality in India, which can also take an effective part to improve the world’s environment.
Source: U.S. Energy Information Administration, International Energy Statistics
India is the fourth largest energy consumer in the world in 2011 [15] after China, US and Russia. The continuous rising energy demand for its dynamic economic growth and socio economic development with modernization, makes India worlds one of the largest economy on a purchasing power parity basis according to World Bank data [15]. There are huge increasing urbanization and life standard change in the lifestyle of country’s citizen make them more dependent over energy. There are also increasing
3. Energy & Sustainability India is still developing and to maintain its growth there should be a continuous supply of energy. In India the energy demand is mainly fulfill by the fossil fuel burning. Though it has significant domestic fossil fuel resources it mainly depends on fossil fuel import, 38% import rise in 2012 [15].
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usage of space conditioner in residential, industrial, and commercial areas. People use conventional space conditioning system and there are huge energy requirement for this purpose. The increasing use of air conditioning system also rise emission of HFCs which is the main reason of global warming. Conventional space conditioning system extract heat in atmosphere by exchanging heat with the air by forced convection method. In case Ground Coupled Heat Pump systems here heat pump extract heat from the room and convey it to the ground heat exchanger (GHE). In ground heat is exchanged by direct exchange of heatdue to temperature difference. There are high fluctuation in atmospheric air due to cyclic change in temp. Though the temperature below 1-2m of earth surface is almost steady and same throughout the year [11]. So using GCHPs can decrease energy use due to its high energy
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International e-Journal For Technology And Research-2017 efficiency with decreasing GHGs emission. In India due to its geographical scenario there are huge variety of climate changes in different location. Using GCHPs can surely meet its space conditioning requirement efficiently and reduce its energy usage with decreasing HFC emission. Ground source heat pump can help its sustainable development.
4. Present Scenario: India and
Table 1. Top fifteen countries on direct use [19] Here China occupies the top position of the list of direct user of geothermal energy. Some 14% of these direct use energy is utilized for space heating and cooling purpose in China. The no of geothermal energy user countries has more than double since 1975, increasing from 10 in 1975 to 24 in 2004 [18]. The contribution of geothermal energy supply is 7.1% in total renewable energy supply in the earth. Many countries already make many rules and policies to give
the world In the international energy tables, geothermal energy is categorized among the ―new renewable‖ though it is used since dawn of civilization in various way [16]. Using geothermal steam first commercially electricity produced in 1913 and the utilization is increased rapidly in last two decades in the form of both electricity generation and direct use. Especially direct use of geothermal energy increased 45% in all over the world from 1999 to 2004. Still now very little fraction of potential of geothermal energy is discovered, so there are plenty of space to discover the potential of these energy [17]. Electricity produced from geothermal energy is in 24 countries [18] and among top 15 countries there are 10 developing nation [11]. Geothermal energy used directly in 78 countries till 2010 [18] and among top 15 countries, who are direct user of geothermal energy, there are 6 developing nations [Table 1].
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enthusiasm for increasing the use of geothermal energy. India has good potential for geothermal energy and there are potential of 10,600 MW of power extraction. But yet any geothermal project has not been started [18]. But due to increasing environmental degradation now India shifting its focus to clean and eco-friendly energy sources and geothermal could be very strong contender. Total primary energy used in India is 775 Mtoe in 2013 [fig 2] [20].
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International e-Journal For Technology And Research-2017 Fig 2 Total installed Power generation Capacity (end of January 2017) [20]
heating/cooling. Though these energy is available
In India there are huge energy requirement which comes mainly from fossil fuel burning. The fossil fuel burning is the main source of CO2 emission. India is in no 4th position in top 20 CO2 emitted countries [21]. Here below is the list of 20 countries according to CO2 emission (data are foe 2011) [Table-2]. Table 2. List of top 20 countries according to CO2 emission [2] Though India has a good carbon credit score [22], India produce huge amount of CO2 gas which trigger the Global warming. So as a responsible country, India has to find how to reduce energy use and efficiently use of these nonrenewable energy sources, which help to reduce degradation of environment. The geographical position of India place it in tropical region, which surrounded by Himalayan mountain range in north and by Indian Oscan in west, east and south [23]. There are a desert region and also a location which is extremely cold in throughout the year. So there are huge requirement of energy for space conditioning and if some portion of it comes from geothermal energy source there can be a huge energy savings. Also GSHPs can reduce CFC emission and improve air quality.
from the very first, but the main growth in the direct use of GSHP is found only in last decade. Due to the ability to use ground energy anywhere in the earth virtually to meet any load, it is now in main attraction for utilization of renewable source in space conditioning purpose. Though GSHPs are used in many countries but in India it is very much neglected. Now government realize and started various R&D to explorer the potential and its commercial viability [24]. Ambient temperature in India varies from -10 ⁰ C to 50 ⁰ C depending on the location, but earth temperature remains same throughout the year which generally lies between 16-24 ⁰ C, which is roughly equal to the mean air temperature [24]. GCHPs uses the earth as a heat source in winter season or cold climate zone and utilize earth as a heat sink in summer season or hot climate zone. COP of HVAC system effected due to change in temperature, whereas the
5. Ground coupled Heat pump applications and type There are two major types of geothermal energy utilization. Electricity production and direct use. From the dawn of civilization this low enthalpy energy is used various way. They are mainly bathing and washing, horticulture, aquaculture and space
constant temperature in earth maximize COP or EER of GCHP system. EER or COP decrease with increase in ambient temperature in conventional space
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International e-Journal For Technology And Research-2017 conditioning system. Still many research work continues to evaluate the performance and commercial viability in Indian climatic region and government also now start encourage their people or stake holder for deployment Geothermal Heat Pump in India due to its high energy competence and ecological affability. The GCHPs incorporate mainly 3 methods to exchange heat with ground, they use ground, groundwater or surface water as energy reservoir. GCHP systems are categorized by American Society of Heating Refrigerating and Air conditioning Engineers
In case of GCHP condenser is replaced by GHE which grounded under 2-6 meter depth and in case of SWHPs condenser id submerged in nearby surface water and exchange heat with it (its initial cost is low due to non-requirement of digging). Surface water is excellent thermal reservoir if it is used suitably. There can be two types of GCHPs depending upon GHEs, horizontal GCHP and Vertical GCHP. Vertical GCHP consumes less ground space and can achieve higher COP or EER in comparison of horizontal GCHP. In case of GEHPs there are a refrigerant cycle which exchange heat with ground water extracted from extraction well and reject through rejection well. A schematic diagram of a GWHP is given below (fig: 4). The major advantages of GWHP are:
Establishment investments are low in compare to other GSHP Wells with trenches o big surfaces are not needed Deep boring of rejection well is not necessary.
Fig: 4 Schematic diagram of a GWHP (ASHRAE) [25]: (a) Surface water heat pump (SWHP), (b) Ground water heat pump (GWHP) and (c) Ground coupled heat pump (GCHP) systems (fig: 3)
7. Application and future development The geothermal cooling or heating can be effective in
Surface water heat pump (SWHP)
Fig: 3
6. Description The GSHP systems are basically 2 types. (1) closedloop heat pump and (2) open-loop heat pump. GCHPs and SWHP are example of close-loop system and GWHPs are open loop system. In case of close loop system working fluid convey heat from evaporator, which is extracted from room, to condenser and reject it to the earth and again goes to evaporator (in cooling mode) [11]. all kind of climate zones [11]. GCHP use ground as
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International e-Journal For Technology And Research-2017 heat source (in heating mode) and heat sink (in cooling mode) to meet any lode in any location virtually. For space heating and cooling purpose there huge requirement of energy in every country. In developing country there are huge requirement of continuous energy supply for its sustainable development. Due to its geographical location there are various climate condition in India, but due to in tropical zone the weather condition is mainly warm weather. There are also some area where cold freeze condition also be found. GCHPs are used as space conditioner and also it can supply hot water without any fossil fuel burning. It also be used to defreeze the land area in many country. In commercial, residential, and office building GCHP can be used and it will help to minimize the energy bill and also mitigate environment pollution degradation. By using of GCHP we can also use this heat in process. In extreme cold climatic zone GCHPs are used with a solar heat collector attachment [11] to meet excess the heat requirement. This full system is called Hybrid GCHP with solar collector. In extreme hot climatic zone due to heat depletion in GHEs can reduce the efficiency of GCHP system [11]. But the GCHP with cooling tower attachment can reduce the thermal depletion in the ground and also maintain the efficiency or COP or EER of the system in highly warm region. Fig: 5 Schematic of HGCHP systems [11]
The components of GCHPs (pump and compressor) liberate heat which can be used to preheat and also it can be utilize in the process which will increase the performance (auxiliary cooling) [11]. GSHPs are also be used for defrosting of ground in many country. In India there are huge variety of climatic zone and there are some places where ground is frost in winter
season. GSHP system can be used there to defrost the land and ready for utilization [16].
CONCLUSION Geothermal energy is one of renewable energy sources, employed in many parts of the world for many years. Many developing country is utilize geothermal energy as it is easy available and inexhaustible. It can also reduce dependency over fossil fuel and reduce environment pollution degradation. These energy can utilize in two ways; (1) electricity production and (2) direct use. India is a developing country, it has a huge requirement of energy supply, which is mainly dependent on fossil fuel burning. So it faces the consequences of environmental degradation and like other country it already focused on the renewable energy utilization. Though it has huge reserve of geothermal resources; still now the implementation of utilization of these ground energy in its research stage. As India is in tropical region, there are mainly warm climatic zone and for better comfort there are huge requirement of the use of space conditioning systems. The use of GSHPs can minimize its dependency over conventional energy resources and also decrease the emission of GHGs. The GSHPs can achieve more COP or EER than conventional ACHPs and reduce the energy consumption for space conditioning of the country. All stake holders like HVAC Contractors & suppliers, Food Processing Units and Manufacturers, Builders & contractors, Cold Storage, Hotel or Restaurant owners, Industry owners, Social Institutes, Schools owners can enjoying the benefits of GCHP by very little changes or up-gradations in their current space conditioning systems and also they can take part in countries sustainable energy development and improvement of environment for their future generations.
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IDL - International Digital Library Of Technology & Research Volume 1, Issue 5, May 2017
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