Glaciers are melting, sea levels are rising, cloud forests are dying, and wildlife is scrambling to keep pace. It’s becoming clear that humans have caused most of the past century’s warming by releasing heat-trapping gases as we power our modern lives. In 2013, 12,000 peer reviewed papers on climate science were analyzed. This analysis showed that 97% of scientists believe that climate change is happening and is human-caused.We call the result global warming, but it is causing a set of changes to the Earth’s climate, or long-term weather patterns, that varies from place to place.
As the Earth spins each day, the new heat swirls with it, picking up moisture over the oceans, rising here, settling there. It’s changing the rhythms of climate that all living things have come to rely upon.Energy conservation reduces the need for energy services, and can result in increased environmental quality, national security, personal financial security and higher savings.
It is at the top of the sustainable energy hierarchy. It can be achieved either by using energy more efficiently or by reducing the amount of services used. Energy can be conserved by reducing wastage and losses, improving efficiency through technological upgradation and improved operation and maintenance.Energy scenario in IndiaEnergy has become one of the important assets for a developing country like India. According to the US Energy Information Administration (EIA), India was the world’s third largest energy consumer as per the data of 2013, after China and the United States of America. Although India has a lot of fossil fuel resourses, there is a large dependency on the energy imports. In 2015,.
This section deals with current amount of energy India is producing and the sources vailable for the same.(Source- US EIA)Nearly 80% of total electricity generated in India is from coal. As on 31.03.16, the estimated reserves of coal were 308.80 billion tonnes, an addition of 2.
20 billion tonnes over the last year. India was the third top coal producer in 2015, according to the BP Statistical Review of World Energy, June 2017. The average quality of the Indian coal is not very high and this necessitates the import of high quality coal to meet the requirement of steel plants. Import of coal has steadily increased from 43.08 MTs during 2006-07 to 199.88 MTs during 2015-16.A replacement for coal will not only reduce India’s import dependency but also reduce dependency on an environment polluting source of energy which is also non renewable in nature (prone to depletion)Renewable energy sourcesThere is high potential for generation of renewable energy from various sources such as wind, solar, biomass, an hydropower. The total potential for renewable power generation in the country as on 31.
03.16 is estimated at 1198856 MW. This includes wind power potential of 102788 MW (8.57%) at 80m hub height, wind power potential of 302235 MW (25.21%) at 100 m hub height, SHP (small-hydro power) potential of 19749 MW (1.65%), Biomass power of 17,538 MW (1.46%), 5000 MW (0.42%) from bagassebased cogeneration in sugar mills, 2556 MW (0.
21%) from waste to energy and solar power potential of 748990 MW (62.48%). Electricity generatedThe all India gross electricity generation from utilities was 6,70,654 Giga Watt-Hours (GWh) during 2006-07. It rose to 11,67,584 GWh during 2015-16. The production of electricity from utilities has increased from 11,16,850 GWh during 2014-15 to 11,67,584 GWh during 2015-16, registering an annual growth rate of about 4.54%.
Total Electricity generation in the country, from utilities and non-utilities taken together during 2015-16 was 13,35,956 GWh. Out of the total electricity generated through utilities, 9,43,013 GWh was generated from thermal and 1,21,377 GWh was from hydro and 37,414 GWh was generated from nuclear sources. Total output from non-utilities was 1,68,372 GWh. (Source-Indian energy statistics 2016, Bureau of Energy Efficiency India, BP Statistical Review of World Energy, US Energy Information Administration)Energy Crisis in IndiaEnergy consumption in India is characterised by low per capita level and a large disparity between urban and rural areas.
Primary energy consumption in India more than doubled between 1990 and 2013, reaching an estimated 775 million tons of oil equivalent. India has the second-largest population in the world, at nearly 1.3 billion people in 2014, growing about 1.
4% each year since 2004, according to World Bank data. At the same time, India’s per capita energy consumption is one-third of the global average, according to the International Energy Agency (IEA), indicating room for higher energy demand in the long term as the country continues its economic development.Per capita electricity consumption (Values in KWh per capita)- comparision (source – The World Bank Data, IEA)Country KWh consumed per capitaIndia 806USA 12987UK 5130Japan 7820China 3927Pakistan 471 There have been severe electricity shortages in India. Significant parts of the country, particularly in rural areas, do not have access to electricity.
The IEA estimates that overall household electrification in India was 81%, representing 237 million people without electricity, in 2013. Although 96% of urban households had electricity, only 74% of rural households had access, and often the rural consumers experienced much more frequently interrupted electricity supply. This is due to insufficient fuel supply and power generation and transmission capacity, disruptions in domestic fuel supplies, and transmission and distribution losses and technical problems in moving electricity between various states. (World Bank data, International Energy Agency, US Energy Information Aministration)Need of renewable energy in IndiaDespite having large coal reserves and overall growth in coal and natural gas production over the past two decades, India is increasingly dependent on imported fossil fuels. India’s current administration under Narendra Modi has a goal of reducing India’s import dependency on oil and natural gas to two-thirds by 2022 and to half by 2030. The energy we produce and import is still not enough to meet the current needs of the country, keeping in mind the low per capita consumption of electricity.To make India self sufficient in terms of energy production and meet the need of growing population, India will have explore and develope other sources of producing energy. With depleting fossil fuel reserves and concerns about its environmental impact, renewable energy is the only long-term solution.
Renewable energy production has a high potential of the development in India given its rich resources. This is the share of current installed renewable power capacity of India. The ministry of new and renewable energy has the target of producing 175 GW renewable energy by 2022. Renewable energy can re-energize India’s economy by creating millions of new jobs, allowing the country to achieve energy independence, reduce its import depenency.Renewable energy has particular relevance in remote and rural areas, where 74 percent off the people do not have the access to reliable sources of energy. As we have seen that there is insufficient fuel suppy and lack of good infrastructure for transmitting and distributing this fuel, installing renewable energy plants right at the place of use can be of great advantage.Electricity consumption by Industrial sector40.01% of the total electricity produced in India is consumed by the industrial sector, which is the maximum amount consumed by any sector.
By promoting new technologies, if we reduce the electricity consumed by industries, the government of India can divert its attention on electrification of rural areas. In short if electrity consumption in urban areas is reduced, problems of other important sectors, like agriculture in the villages, can also be solved. Thus it is important to install renewable energy production in both rural and urban area.Further in this paper we will be focusing on technologies to reduce energy consumption in HVAC units either by utilising renewable energy sources or implementing design changes to reduce overall electricity consumption.(source http://www.cea.nic.in/reports/others/planning/pdm/growth_2017.
pdf, Central electricity authority of India)Energy conserving technologies in Air conditioning systems 1) Solar hybrid HVAC Product principle:It increases the cooling system efficiency and reduces operating expenses by replacing a percentage of mechanical energy required to power a compressor (saving electricity) with modulated solar thermal energy. Product design:The hot gas discharge line from the compressor is connected to the top inlet of a Smart Solar Panel. Heat and pressure are added to the refrigerant, generated by the sun and the heated/pressurized refrigerant is returned from the panel outlet to the HVAC unit’s condenser. By adding heat/pressure to the refrigerant by this method, compressor’s energy consumption can be reduced by up to 40%. This solar thermal system displaces a portion of the mechanical energy used by variable capacity, multi-stage, and variable speed compressors, which keeps the compressor in low stage, low range or low capacity, while delivering full and part-load cooling requirements. This effect creates significant energy savings.
Design of Solar Thermal Panel: It is a patented computer-controlled parabolic concentrator which produces more energy than any other panel of the same size. This technology has solved two major issues with solar thermal panels: degradation and stagnation. Solar Thermal Panels currently in use, cannot regulate the amount of heat being added to the working fluid. When systems are not in use they can cause extreme heat buildup and even damage the coatings of an evacuated tube panel. When integrated with HVAC equipment this could cause severe damage to the refrigerant which may cause the compressor to fail. It includes a plurality of elongated parabolic reflectors mounted within a glass-topped enclosure for pivotal movement such that each reflector is incrementally pivoted throughout the course of a day to remain substantially perpendicular to the sun. The incremental pivotal movement is caused by a motor energized from a solar switch having solar cells that also pivot throughout the day so that in one position of the switch, no electricity is being generated and transferred to the motor, but in a second position, the switch receives solar radiation and energizes the motor to again incrementally pivot each reflector along with the solar switch.
The reflectors are therefore incrementally pivoted throughout the course of a day to follow the sun for optimal collection of solar radiation which is used to heat liquid carried by tubes positioned at the axis of generation of the parabolic reflectors and/or strips of solar cell material so that electricity can be generated alone, liquid heated alone, or liquid heated and electricity generated simultaneously.Cost analysis: • For a 10 ton A/C which is equivalent to 12HP VRV, consuming 11 kWh of electricity, for 25 working days, operating 10 hrs /day with 60% load.• Total monthly electricity charge = Rs 0.6*10*25*11*9 = Rs 14850 (Assuming the average cost of electricity in urban India for commercial sector to be 9 Rs/kWh)• This Hybrid Thermal System saves 40% of energy consumption lowering monthly charge by Rs 6000• Total Panel installed cost is about Rs1.75 lakhs which will thus be recovered in 30 months (Rs 1.75 lakhs / Rs 6000 ? 29.167 months )2) Ultraviolet Germicidal Irradiation (UVGI) in HVAC systemsProduct principleThe aim of using UVGI technology in HVAC industry is to improve the effiency of its Air handling units (Coils) which leads to overall efficiency increase and saves energy consumption of the unit.
The technology of cleaning the heat exchanger coils with UV rays has been improvised by Alfaa UV, by developing, with the help of simulations and calculations, an efficient UVGI system with optimum position and number of UV lamps and dosage, which has made the technology accurate and ecconomical.Biofilm on heat exchanger coilsHeat exchangers (evaporator and condensor) of an air conditioning system use cooling coils which consists of copper tubes to which aluminium fins are attached (to increase the air side surface area). The water or refrigerant flowing through the tubes wets the coils surface causing microorganism growth. A film of Pseudomonas airuginosa is developed on the outer surface of coil, thus interacting with the air flowing outside. This is known as the formation of biofilms on the heat exchanger coil.
Problems due to biofilm1) Biofilm are a source of biological contamintion. It deteroites the indoor air quality (IAQ). The miroorganisms are also a source of diseases. Plus sticky films attract dust particles.2) The biofilm covering decreases the free flow area. The causes the velocity of the flowing air to increase.
As the velocity head increases, the pressure head drops, thus increasing the load on blowers (increased electricity consumption).3) The films act as thermal insulation, reducing effciency of heat transfer between the air and fluid across the coil (heat transfer coefficiant decreases).4) As the heat transfer coefficient decreases, chilled water flow rate increases, causing lower water side temperature difference. As conditions are non-optimum, more energy is consumedBiofilm thickness (fins) Energy usage increase0.12 inch 10.
8%0.24 inch 21.5%0.
36 inch 32.2%Cleaning of coils –using UV radiationsConventional methods of periodic cleaning of coils include pressure washing and chemical cleaning. Both involve manpower and maintanance cost. These can also damage sensitive parts and chemical can be dangerous for indoor occupants.Installing UVGI system – The installed UV lamps emit ultraviolet radiation which directly attacts the microorganisms. It destroys the exsisting biofilm and also prevents any future growth.
Once the system is installed, no periodic maintenance or manpower is required. As the coils are always clean, the unit saves on a lot of electricity.UVGI helps in saving-Energy consumed in running the blowers-Cooling energy-Maintenance cost1) Air flow rate increase by 15%2) Electricity consumption decrease by 10.2%3) Bacteria accumulation decrease by 97.2% The better method Although this technology of cleaning coil with UV rays is used in many HVAC systems today, many users cannot decide optium number and position of the UV tubes to be used. Using less number of tubes and fixing them at incorrect locations will create “Dead zones” on the coil surface where the exposure to UV rays is not enough.
Microorganisms which require high dosage will grow in these zones thus defeating the purpose of the UV tube system.Using more number of tubes than required is uneconomical and also can cause damage to the UV parts inside.Alfaa UV uses a simulation software coupled with computational fluid dynamics. It can calculate the exact dosage recieved by the microbes as they travel through the air handing units. The simulation can calculate the exact UV irradiance at every point of the coil surface. It highlights the area of low irradiance and reports maximum and average irradiance across the coil surface. The report also provides ideal mounting positions and distances for the tubes with respect to coil surfaces.
Cost Analysis:3) Solar powered vapour absorption systemPrincipleVapour absorption systemIn the case of conventional vapour compression system, the compressor is the most energy consuming component. External work has to be done on the compressor in order to increase the pressure and temperature of the refrigerant. But in case of vapour absorption system, the compressor is replaced by the absorber-generator unit. The absorbent use in the absorber absorbs the refrigerant by releasing some amount of heat. This mixture then passes through a heat exchanger to the generator. The generator is given a heat supply. Absorbing this heat, the refrigerant, at high temperature and high pressure, seperates out from the mixture. Thus we have achieved pressure increase without a compressor.
Replacement of the compressor, which consumes high grade eletrical energy with heat energy, which is low grade energy, makes the vapour absorption system more favourable.Generator heating – using solar energyThe generator requires external heating. This heating can be provided by electrical means or by burning or fossil fuels in a furnace. As energy consumption is already been reduced by replacing the compressor, by energy conservation can be implemented by using renewable source of energy – Solar energy. This system uses a solar flat plate collector. Flat plate collector is an insulated box containing a dark absorber plate under a transparent or a translucent cover.
The absorber plate is made up of copper as it has high thermal conductivity. Absorbing efficiency is 97%. Moreover black paint is used over the copper plate which has absorptance 0.
85 to 0.9. Hence the plate ensures that maximum heat is tranfered to the generator. On calculations, solar vapour absorption refrigeration system has a coefficient of performance (COP) about 0.69, the COP of the entire system is about 0.58. These values were calculated by considering the capacity as 1TR.
Using water at 25 degree Celsius as the condensing medium and eveporator pressure as the atmospheric pressure, temperature and pressure were calculated at every point and plotted on the ph curves. From the curves we can know the values of enthalpy at every point. As we know that the refrigerting effect is 1TR, mass flow rate of ammonia through the evaporator can be obtained usingMr (change in enthalpy) =1TRUsing the Mr, heat remove from the compressor is calculated and using enthalpy values from the curve heat input to the generator can also be obtained. Cop= (refrigerating effect) / (heat input in generator)The value of COP shows that this system is feasible and plus the use of solar energy has reduce the electric load of the system.
National Institute of technology, Kurukshetra has adapted this system in their premises. As it is not a commercial organisation and the product is not yet floated by any commercial organisation in market, the cost analysis of the product is not available.