Geothermal Energy Use in Switzerland

To give an overview of geothermal energy use in Switzerland, its principle of operation and the different available technologies are described. Geothermal energy refers to the use of energy taken from the underground. The use of geothermal technologies is sustainable and produces heat that can be used instead of oil or gas to heat a house and produce warm water. In Switzerland, the consumption of geothermal energy is small and only accounts for 1.0 % of the whole consumption of energy (BFS, 2010).

The technologies in the field of geothermal energy use are various. Their applicability is dependent on the specific underground as well as the local conditions such as available space, groundwater appearance, and the environmental standards in the particular region. Moreover, there are technologies that are used in a more widely way while others are new and still in research.

Although the downhole heat exchangers, energy baskets, and underground registers account together for 73.2 %, geothermal energy baskets take on only a minor role. They represent the technology with the smallest percentage rate and are thus to be said a niche product (Geothermie, 2011b). This might be due to the fact that this technology was only brought on the market 

How Geothermal Energy Baskets work

Geothermal energy baskets are made of spiral wound polyethylene tubes that are fastened with a metal skeleton (BFE, 2005a). There are two types available: conical and cylindrical energy baskets with different dimensions (see table 3 and 4).

The chosen dimensions of the baskets are dependent on the available space and the geological conditions of the soil. After having evaluated the size, the baskets are installed in 1-1.5m soil depth and are connected with each other. The depth is chosen to 1-1.5m because the baskets need to be installed below the frost line to prevent the baskets from freezing damage (BetaTherm, 2009b). The tubes are filled with a liquid made of water and anti-freezing agents. This liquid is used to absorb the warmth of the soil. The absorbed warmth of the liquid is then passed down to a heat pump which is used as water heating system in the household.

 

Differential Relay

June 8, 2019 by Electrical4U

The relays used in power system protection are of different types. Among them differential relay is very commonly used relay for protecting transformers and generators from localised faults.
Differential relays are very sensitive to the faults occurred within the zone of protection but they are least sensitive to the faults that occur outside the protected zone. Most of the relays operate when any quantity exceeds beyond a predetermined value for example over current relay operates when current through it exceeds predetermined value. But the principle of differential relay is somewhat different. It operates depending upon the difference between two or more similar electrical quantities.

Definition of Differential Relay

The differential relay is one that operates when there is a difference between two or more similar electrical quantities exceeds a predetermined value. In the differential relay scheme circuit, there are two currents come from two parts of an electrical power circuit. These two currents meet at a junction point where a relay coil is connected. According to Kirchhoff Current Law, the resultant current flowing through the relay coil is nothing but the summation of two currents, coming from two different parts of the electrical power circuit. If the polarity and amplitude of both the currents are so adjusted that the phasor sum of these two currents, is zero at normal operating condition. Thereby there will be no current flowing through the relay coil at normal operating conditions. But due to any abnormality in the power circuit, if this balance is broken, that means the phasor sum of these two currents no longer remains zero and there will be non-zero current flowing through the relay coil thereby relay being operated.

In the current differential scheme, there are two sets of current transformer each connected to either side of the equipment protected by differential relay. The ratio of the current transformers are so chosen, the secondary currents of both current transformers matches each other in magnitude.
The polarities of current transformers are such that the secondary current of these CTs opposes each other. From the circuit is clear that only if any nonzero difference is created between this to secondary currents, then only this differential current will flow through the operating coil of the relay. If this difference is more than the peak up value of the relay, it will operate to open the circuit breakers to isolate the protected equipment from the system. The relaying element used in differential relay is attracted armature type instantaneously relay since differential scheme is only adapted for clearing the fault inside the protected equipment in other words differential relay should clear only the internal fault of the equipment hence the protected equipment should be isolated as soon as any fault occurred inside the equipment itself. They need not be any time delay for coordination with other relays in the system.

Types of Differential Relay

There are mainly two types of differential relay depending upon the principle of operation.

1. Current Balance Differential Relay
2. Voltage Balance Differential Relay

In current differential relay two current transformers are fitted on the either side of the equipment to be protected. The secondary circuits of CTs are connected in series in such a way that they carry secondary CT current in same direction.

The operating coil of the relaying element is connected across the CT’s secondary circuit. Under normal operating conditions, the protected equipment (either power transformer or alternator) carries normal current. In this situation, say the secondary current of CT1 is I1 and secondary current of CT2 is I2. It is also clear from the circuit that the current passing through the relay coil is nothing but I1-I2. As we said earlier, the current transformer’s ratio and polarity are so chosen, I1 = I2, hence there will be no current flowing through the relay coil. Now if any fault occurs in the external to the zone covered by the CTs, faulty current passes through primary of the both current transformers and thereby secondary currents of both current transformers remain same as in the case of normal operating conditions. Therefore at that situation the relay will not be operated. But if any ground fault occurred inside the protected equipment as shown, two secondary currents will be no longer equal. At that case the differential relay is being operated to isolate the faulty equipment (transformer or alternator) from the system.
Principally this type of relay systems suffers from some disadvantages

1. There may be a probability of mismatching in cable impedance from CT secondary to the remote relay panel.
2. These pilot cables’ capacitance causes incorrect operation of the relay when large through fault occurs external to the equipment.
3. Accurate matching of characteristics of current transformer cannot be achieved hence there may be spill current flowing through the relay in normal operating conditions.

Percentage Differential Relay

This is designed to response to the differential current in the term of its fractional relation to the current flowing through the protected section. In this type of relay, there are restraining coils in addition to the operating coil of the relay. The restraining coils produce torque opposite to the operating torque. Under normal and through fault conditions, restraining torque is greater than operating torque. Thereby relay remains inactive. When internal fault occurs, the operating force exceeds the bias force and hence the relay is operated. This bias force can be adjusted by varying the number of turns on the restraining coils. As shown in the figure below, if I1 is the secondary current of CT1 and I2 is the secondary current of CT2 then current through the operating coil is I1 – I2 and current through the restraining coil is (I1 + I2)/2. In normal and through fault condition, torque produced by restraining coils due to current (I1+ I2)/2 is greater than torque produced by operating coil due to current I1– I2 but in internal faulty condition these become opposite. And the bias setting is defined as the ratio of (I1– I2) to (I1+ I2)/2.

It is clear from the above explanation, greater the current flowing through the restraining coils, higher the value of the current required for operating coil to be operated. The relay is called percentage relay because the operating current required to trip can be expressed as a percentage of through current.

CT Ratio and Connection for Differential Relay

This simple thumb rule is that the current transformers on any star winding should be connected in delta and the current transformers on any delta winding should be connected in star. This is so done to eliminate zero sequence current in the relay circuit.
If the CTs are connected in star, the CT ratio will be In/1 or 5 A
CTs to be connected in delta, the CT ratio will be In/0.5775 or 5×0.5775 A

Voltage Balance Differential Relay

In this arrangement the current transformer are connected either side of the equipment in such a manner that EMF induced in the secondary of both current transformers will oppose each other. That means the secondary of the current transformers from both sides of the equipment are connected in series with opposite polarity. The differential relay coil is inserted somewhere in the loop created by series connection of secondary of current transformers as shown in the figure. In normal operating conditions and also in through fault conditions, the EMFs induced in both of the CT secondary are equal and opposite of each other and hence there would be no current flowing through the relay coil. But as soon as any internal fault occurs in the equipment under protection, these EMFs are no longer balanced hence current starts flowing through the relay coil thereby trips circuit breaker.

There are some disadvantages in the voltage balance differential relay such as a multi tap transformer construction is required to accurate balance between current transformer pairs. The system is suitable for protection of cables of relatively short length otherwise capacitance of pilot wires disturbs the performance. On long cables the charging current will be sufficient to operate the relay even if a perfect balance of current transformer achieved.
These disadvantages can be eliminated from the system by introducing Translay system/scheme which is nothing but modified balance voltage differential relay system. Translay scheme is mainly applied for differential protection of feeders.

Here, two sets of current transformers have connected either end of the feeder. Secondary of each current transformer is fitted with individual double winding induction type relay. The secondary of each current transformer feeds primary circuit of double winding induction type relay. The secondary circuit of each relay is connected in series to form a closed loop by means of pilot wires. The connection should be such that, the induced voltage in secondary coil of one relay will oppose same of other. The compensating device neutralizes the effect of pilot wires capacitance currents and effect of inherent lack of balance between the two current transformers.

Under normal conditions and through fault conditions, the current at two ends of the feeder is same thereby the current induced in the CT’s secondary would also be equal. Due to these equal currents in the CT’s secondary, the primary of each relay induce same EMF. Consequently, the EMF induced in the secondaries of the relay is also same but the coils are so connected, these EMFs are in opposite direction. As a result, no current will flow through the pilot loop and thereby no operating torque is produced either of the relays.

But if any fault occurs in the feeder within the zone in between current transformers, the current leaving the feeder will be different from the current entering into the feeder. Consequently, there will be no equality between the currents in both CT secondaries. These unequal secondary CT currents will produce unbalanced secondary induced voltage in both of the relays. Therefore, current starts circulating in the pilot loop and hence torque is produced in both of the relays.

As the direction of secondary current is opposite into relays, therefore, the torque in one relay will tend to close the trip contacts and at the same time torque produced in other relay will tend to hold the movement of the trip contacts in normal un-operated position. The operating torque depends upon the position and nature of faults in the protected zone of feeder. The faulty portion of the feeder is separated from healthy portion when at least one element of either relay operates.

This can be noted that in translay protection scheme, a closed copper ring is fitted with the Central limb of primary core of the relay. These rings are utilised to neutralise the effect of pilot capacity currents. Capacity currents lead the voltage impressed of the pilot by 90o and when they flow in low inductive operating winding, produce flux that also leads the pilot voltage by 90o. Since the pilot voltage is that induced in the secondary coils of the relay, it lags by a substantial angle behind the flux in the field magnetic air gap. The closed copper rings are so adjusted that the angle is approximately 90o. In this way fluxes acting on the disk are in phase and hence no torque is exerted in the relay disc.

  

Graphene-based supercapacitors

A capacitor is an energy storage medium similar to an electrochemical battery. Most batteries, while able to store a large amount of energy are relatively inefficient in comparison to other energy solutions such as fossil fuels. It is often said that a 1kg electrochemical battery is able to produce much less energy than 1 litre of gasoline; but this kind of comparison is extremely vague, mathematically illogical, and should be ignored. In fact, some electrochemical batteries can be relatively efficient, but that doesn’t get around the primary limiting factor in batteries replacing fossil fuels in commercial and industrial applications (for example, transportation); charge time.

High capacity batteries take a long time to charge. This is why electrically powered vehicles have not taken-off as well as we expected twenty or thirty years ago. While you are now able to travel 250 miles or more on one single charge in a car such as the Tesla Model S, it could take you over 43 hours to charge the vehicle using a standard 120v wall socket in order to drive back home. This is not acceptable for many car users. Capacitors, on the other hand, are able to be charged at a much higher rate, but store (as already mentioned) somewhat less energy.

Supercapacitors, also known as ultracapacitors, are able to hold hundreds of times the amount of electrical charge as standard capacitors, and are therefore suitable as a replacement for electrochemical batteries in many industrial and commercial applications. Supercapacitors also work in very low temperatures; a situation that can prevent many types of electrochemical batteries from working. For these reasons, supercapacitors are already being used in emergency radios and flashlights, where energy can be produced kinetically (by winding a handle, for example) and then stored in a supercapacitor for the device to use.

A conventional capacitor is made up of two layers of conductive materials (eventually becoming positively and negatively charged) separated by an insulator. What dictates the amount of charge a capacitor can hold is the surface area of the conductors, the distance between the two conductors and also the dielectric constant of the insulator. Supercapacitors are slightly different in the fact that they do not contain a solid insulator.

Instead the two conductive plates in a cell are coated with a porous material, most commonly activated carbon, and the cells are immersed in an electrolyte solution. The porous material ideally will have an extremely high surface area (1 gram of activated carbon can have an estimated surface area equal to that of a tennis court), and because the capacitance of a supercapacitor is dictated by the distance between the two layers and the surface area of the porous material, very high levels of charge can be achieved.

While supercapacitors are able to store much more energy than standard capacitors, they are limited in their ability to withstand high voltage. Electrolytic capacitors are able to run at hundreds of volts, but supercapacitors are generally limited to around 5 volts. However, it is possible to engineer a chain of supercapacitors to run at high voltages as long as the series is properly designed and controlled.

1) Geothermal heating and cooling : design of ground-source heat pump systems    

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2) Geothermal Reservoir Engineering, Second Edition

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       Geothermal Heating and Cooling

Low-cost air cooling solution earns high laurels to IIT-R

 tudents

Dehradun, Oct 24 The ancient cooling technology of earthenware find their perfect match in two IIT-Roorkee students, who recently developed a new low-cost evaporative air cooling solution using the same technique.
Named Evacool, the unique invention which guarantees less electricity consumption and zero emission of toxic gases, has won Raja Jain and Nimisha Gupta (both students of chemical engineering) the winning title in the recently concluded 'Go Green in the City 2017' competition.
Held at the headquarters of Schneider Electric in Paris, the contest was launched to promote innovative solutions for smarter and more energy efficient cities.
"The existing cooling solutions like ceiling fan, air cooler and air conditioner are either not impactful enough or are resource-heavy due to which there are limited users, as affordability is the major concern.
"To overcome all these limitations, we have designed Evacool which is cost-effective, consumes lesser electricity, emits no toxic gases, and hence, is a greener solution too," Raja Jain, winner of the competition said.
Developed keeping in mind the lower strata of the society, one unit of Evacool costs Rs 4,000 only.
Nonetheless, the low-cost of the unit does not come in way of its performance as it promises to reduce the temperature by "10 degree Celsius".
19,772 applicants from 180 countries had participated in the competition, out of which 12 finalist teams were shortlisted and the team from IIT Roorkee bagged the top position.
students
Dehradun, Oct 24 The ancient cooling technology of earthenware find their perfect match in two IIT-Roorkee students, who recently developed a new low-cost evaporative air cooling solution using the same technique.
Named Evacool, the unique invention which guarantees less electricity consumption and zero emission of toxic gases, has won Raja Jain and Nimisha Gupta (both students of chemical engineering) the winning title in the recently concluded 'Go Green in the City 2017' competition.
Held at the headquarters of Schneider Electric in Paris, the contest was launched to promote innovative solutions for smarter and more energy efficient cities.
"The existing cooling solutions like ceiling fan, air cooler and air conditioner are either not impactful enough or are resource-heavy due to which there are limited users, as affordability is the major concern.
"To overcome all these limitations, we have designed Evacool which is cost-effective, consumes lesser electricity, emits no toxic gases, and hence, is a greener solution too," Raja Jain, winner of the competition said.
Developed keeping in mind the lower strata of the society, one unit of Evacool costs Rs 4,000 only.
Nonetheless, the low-cost of the unit does not come in way of its performance as it promises to reduce the temperature by "10 degree Celsius".
19,772 applicants from 180 countries had participated in the competition, out of which 12 finalist teams were shortlisted and the team from IIT Roorkee bagged the top position.

Startup India                                                                                   

is a flagship initiative of the Government of India, intended to build a

strong eco-system for nurturing innovation and Startups in the country that will drive sustainable

economic growth and generate large scale employment opportunities. The Govern

ment through

this initiative aims to empower Startups to grow through innovation and design.

In order to meet the objectives of the initiative, Government of India is announcing this Action Plan

that addresses all aspects of the Startup ecosystem. With this Action Plan the Government

hopes to accelerate spreading of the Startup movement:

• From digital/ technology sector to a wide array of sectors including agriculture,

manufacturing, social sector, healthcare, education, etc.; and

• From existing tier 1 cities to tier 2 and tier 3 citites including semi-urban and rural areas.

The Action Plan is divided across the following areas:

• Simplification and Handholding

• Funding Support and Incentives

• Industry-Academia Partnership and Incubation

The definition of a Startup (only for the purpose of Government scheme

s) has been detailed in

Annexure I.

Startup India                                                                                                                                                                       Startup India campaign is based on an action plan aimed at promoting bank financing for start-up ventures to boost entrepreneurship and encourage start ups with jobs creation. The campaign was first announced by Prime Minister Narendra Modi in his 15 August 2015 address from the Red Fort. It is focused on to restrict role of States in policy domain and to get rid of "license raj" and hindrances like in land permissions, foreign investment proposal, environmental clearances. It was organized by Department of Industrial Policy and Promotion (DIPP) A startup is an entity that is headquartered in India which was opened less than seven years ago and has an annual turnover less than ₹25 crore The government has already launched iMADE, an app development platform aimed at producing 1,000,000 apps and PMMY, the MUDRA Bank, a new institution set up for development and refinancing activities relating to micro units with a refinance Fund of ₹200 billion                                                                                                                                                                             the Standup India initiative is also aimed at promoting entrepreneurship among SCs/STs, women communities. Rural India's version of Startup India was named the Deen Dayal Upadhyay Swaniyojan Yojana.To endorse the campaign, the first magazine for start ups in India, The Cofounder, was launched in 201

Key points                                                                                             

• Single Window Clearance even with the help of a mobile application
• 10,000 crore fund of funds
• reduction in patent registration fee
• Modified and more friendly Bankruptcy Code to ensure 90-day exit window
• Freedom from mystifying inspections for 3 years
• Freedom from Capital Gain Tax for 3 years
• Freedom from tax in profits for 3 years
• Self-certification compliance
• Innovation hub under Atal Innovation Mission
• Starting with 5 lakh schools to target 10 lakh children for innovation programme
• new schemes to provide IPR protection to start-ups and new firms
• encourage entrepreneurship.
• Stand India across the world as a start-up hub.  

 See also                                                                                         

• Standup India
• Make in India
• Digital India
• Skill India
• Electronics and semiconductor manufacturing industry in India

                       ANSHU HILSA
               
       gmail=anshu2anshu123@gmail.com

  

Plate heat exchangers

                                                                                                                                                                                            Gasketed plate-and-frame heat exchangers provide efficient heat transfer in compact equipment with a small footprint. The units have a flexible design and are easy to service and maintain. The product range is extremely wide and is used in duties for heating, cooling, heat recovery, evaporation and condensation in industries ranging from HVAC, refrigeration, engine cooling, dairy and food to heavier processes like chemical processing, oil production and power generation.                                                                                                                                                                                                                                                                                                                             ANSHU KUMAR                                                                                 Email=anshu2anshu123@gmail.com                                                                                                                                                                        

Geothermal Heat Pump

A geothermal heat pump or ground source heat pump (GSHP) is a central heating and/or cooling system that transfers heat to or from the ground.

It uses the earth as a heat source (in the winter) or a heat sink (in the summer). This design takes advantage of the moderate temperatures in the ground to boost efficiency and reduce the operational costs of heating and cooling systems, and may be combined with solar heating to form a geosolar system with even greater efficiency. They are also known by other names, including geoexchange, earth-coupled, earth energy systems. The engineering and scientific communities prefer the terms "geoexchange" or "ground source heat p to avoid confusion with traditional geothermal power, which uses a high temperature heat source to generate electricity.[1] Ground source heat pumps harvest heat absorbed at the Earth's surface from solar energy. The temperature in the ground below 6 metres (20 ft) is roughly equal to the mean annual air temperature[2] at that latitude at the surface.

Depending on latitude, the temperature beneath the upper 6 metres (20 ft) of Earth's surface maintains a nearly constant temperature between 10 and 16 °C (50 and 60 °F),[3] if the temperature is undisturbed by the presence of a heat pump. Like a refrigerator or air conditioner, these systems use a heat pump to force the transfer of heat from the ground. Heat pumps can transfer heat from a cool space to a warm space, against the natural direction of flow, or they can enhance the natural flow of heat from a warm area to a cool one. The core of the heat pump is a loop of refrigerant pumped through a vapor-compression refrigeration cycle that moves heat. Air-source heat pumps are typically more efficient at heating than pure electric heaters, even when extracting heat from cold winter air, although efficiencies begin dropping significantly as outside air temperatures drop below 5 °C (41 °F). A ground source heat pump exchanges heat with the ground. This is much more energy-efficient because underground temperatures are more stable than air temperatures through the year. Seasonal variations drop off with depth and disappear below 7 metres (23 ft)[4] to 12 metres (39 ft)[5] due to thermal inertia. Like a cave, the shallow ground temperature is warmer than the air above during the winter and cooler than the air in the summer. A ground source heat pump extracts ground heat in the winter (for heating) and transfers heat back into the ground in the summer (for cooling). Some systems are designed to operate in one mode only, heating or cooling, depending on climate. umps" Geothermal pump systems reach fairly high coefficient of performance (CoP), 3 to 6, on the coldest of winter nights, compared to 1.75-2.5 for air-source heat pumps on cool days.[6] Ground source heat pumps (GSHPs) are among the most energy efficient technologies for providing HVAC and water heating.[7][8]

Setup costs are higher than for conventional systems, but the difference is usually returned in energy savings in 3 to 10 years, and even shorter lengths of time with federal, state and utility tax credits and incentives. Geothermal heat pump systems are reasonably warranted by manufacturers, and their working life is estimated at 25 years for inside components and 50+ years for the ground loop.[9] As of 2004, there are over one million units installed worldwide providing 12 GW of thermal capacity, with an annual growth rate of 10%.[10]

Geothermal energy is heat energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. The geothermal energy of the Earth's crust originates from the original formation of the planet and from radioactive decay of materials (in currently uncertain^[1] but possibly roughly equal^[2] proportions). The geothermal gradient, which is the difference in temperature between the core of the planet and its surface, drives a continuous conduction of thermal energy in the form of heat from the core to the surface. The adjective geothermal originates from the Greek roots γη (ge), meaning earth, and θερμος (thermos), meaning hot