18.04.2024 (1) has to go on then has to.pptx

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1. Sustainability in architecture and construction Building level

2. 1. Materials Selection: Choose materials that have a lower environmental impact, such as recycled or reclaimed materials, natural materials like wood or bamboo from sustainable sources, and materials with high levels of recyclability or biodegradability.   Enviromate  in the UK ,   Loopfront  in Norway,   Freegle   &   Freecyle .

3. 2. Energy Efficiency: Design buildings with energy-efficient systems and features, such as insulation, energy-efficient HVAC systems, LED lighting, and renewable energy sources like solar panels or wind turbines. 3. Water Conservation: Implement water-saving technologies such as rainwater harvesting systems, greywater recycling, and low-flow fixtures to reduce water consumption.

4. 4. Waste Management: Develop a comprehensive waste management plan to minimize construction waste and promote recycling and reuse of materials during and after construction. 5. Passive Design Strategies: Incorporate passive design strategies such as orientation for natural light and ventilation, thermal mass, and shading elements to reduce the building's reliance on mechanical systems for heating, cooling, and lighting.

5. 1. Orientation: Properly orienting a building with respect to the sun's path is fundamental. In hot climates, orienting the building to minimize direct sunlight exposure during the hottest parts of the day can reduce cooling loads. Conversely, in cold climates, maximizing south-facing windows can capture more sunlight for passive heating. 2. Natural Ventilation: Designing for natural ventilation involves strategically placing openings such as windows, doors, and vents to facilitate cross ventilation and airflow throughout the building. This helps remove stale air, reduce humidity, and maintain a comfortable indoor environment. 3. Shading: Incorporating shading devices such as overhangs, awnings, louvers, or external blinds can block direct sunlight from entering windows during hot periods while allowing sunlight in during cooler times. This reduces the need for artificial cooling and prevents excessive heat gain. 4. Thermal Mass: Using materials with high thermal mass, such as concrete, brick, or stone, in the building's structure can absorb and store heat during the day and release it gradually at night, helping to stabilize indoor temperatures and reduce temperature fluctuations.

6. 5. Insulation: Proper insulation in walls, floors, and roofs prevents heat transfer between indoor and outdoor environments, reducing the need for heating and cooling. High-quality insulation materials like foam, fiberglass, or cellulose can significantly improve energy efficiency. 6. Daylighting: Maximizing natural daylight through well-placed windows, skylights, and light wells not only reduces the need for artificial lighting but also creates a more pleasant and productive indoor environment. Designing spaces with ample natural light can also enhance occupants' well-being. 7. Green Roofs and Walls: Green roofs and walls, which are covered with vegetation, provide additional insulation, absorb rainwater, reduce heat island effects, and improve air quality. They can contribute to energy savings and enhance the building's overall sustainability. 8. Natural Landscaping: Incorporating native plants, trees, and landscaping features around the building can provide shade, reduce heat absorption from the ground, and create microclimates that enhance comfort and energy efficiency.

7. 9. Cool Roofs: Cool roofs are designed to reflect more sunlight and absorb less heat compared to traditional roofs. They can be made of reflective materials like white membranes, tiles, or coatings that reduce heat gain, especially in hot climates, and lower cooling energy demand. 10. Natural Materials: Utilizing natural and locally sourced materials in construction can reduce embodied energy (energy used in material extraction, manufacturing, and transportation). Materials like rammed earth, straw bales, clay, and timber from sustainable forests can be used for walls, floors, and finishes. 11. Thermal Chimneys: Thermal chimneys, also known as stack ventilation, use the principle of hot air rising to create natural airflow within a building. Placing vertical shafts or chimneys in strategic locations allows hot air to escape, drawing in cooler air from lower levels and improving natural ventilation. 12. Passive Solar Design: Passive solar design maximizes the use of solar energy for heating and lighting. This includes designing buildings with large south-facing windows to capture sunlight, using thermal mass to store heat, and incorporating shading devices to control solar gain based on seasonal variations. 13. Decentralized Ventilation: Instead of centralized HVAC systems, decentralized ventilation systems can be implemented, such as individual room ventilation units or energy recovery ventilators (ERVs). These systems provide targeted ventilation, improve indoor air quality, and reduce energy consumption compared to centralized systems. 14. Hybrid Systems: Combining passive design strategies with active systems, such as solar panels for electricity generation, solar water heaters, or geothermal heat pumps, can create hybrid solutions that maximize energy efficiency and sustainability while meeting specific building requirements. 15. Building Form and Layout: The overall form and layout of a building can influence its energy performance. Compact building designs with efficient floor plans reduce exterior surface area, minimizing heat loss or gain. Additionally, designing for natural daylight penetration throughout the building's interior reduces reliance on artificial lighting. 16. Occupant Behavior: Educating occupants about sustainable practices, such as adjusting thermostat settings, using natural ventilation when possible, and turning off lights and equipment when not in use, can complement passive design strategies and further reduce energy consumption.

8. Air conditioner – Basic working principle

9. Direct vs indirect cooling

10. M ultistage evaporative cooling system A multi stage evaporative cooling system can work according to the humidity of ambient and humidity desired for supply air. When the relative humidity of ambient air is high, only indirect cooling can be used. This reduces the air temperature of supply air, but the humidity remains unchanged. When increase in humidity is also desired, as in dry hot seasons, direct evaporative cooling can be used.

11. Desiccant Cooling System These systems are used in applications where the latent heat load is too high i.e. moisture content desired in supply air is minimal. Energy is saved by using the desiccant to absorb or adsorb the moisture content instead of mechanical equipment. Mechanical energy is then needed only for reducing the temperature of the air.

12. Two stage evaporative cooling systems (direct + indirect)  – the direct system could be functional during the dry season, when humidification of air is required, and indirect system can be used when air primarily needs to be cooled. Three stage evaporative cooling system (direct + indirect + cooling coil)  consists of direct and indirect evaporative cooling together with conventional cooling coil. The addition of cooling coils (chilled water or refrigerants) is helpful in monsoon season when the humidity level is high and dehumidification is required. Fresh air passed through the coils controls both sensible and latent heat requirements. The coils are also useful in winter season when some heating is also required. The drawback of the two stage system is the high humidity level of the supply air. Over a period of time indirect evaporative cooling systems which provide sensible cooling of the air without humidification have emerged in the market.

13. Tri-Generation (Waste to Heat) Trigeneration systems produce heat and electricity which in turn can be used for heating, cooling and hot water heating systems in a building. Electricity produced can also be supplied to the grid if not needed on the site. Trigeneration systems are more commonly used in buildings with readily available waste heat and intense 24 hours operations.

14. In a developing country like India, high volume of waste heat is generated around the year which could be used to produce heat around the year. Thus a technology which uses thermal energy to provide cooling could be a solution to our rising energy crisis. In many buildings like hotels, hospitals, and industries, there is a demand for hot water along with air cooling. Such a scenario is well suited for the application of Tri-generation concept. A tri-generation system produces three forms of energy, i.e. electricity, heating, and cooling which could be used to generate power, hot water, and air conditioning with suitable equipment. The principle of tri-generation is based on the generation of heat energy. Heat captured through burning waste, production of electricity with generators, or heat generated through solar panels could be used to generate hot water through heat transfer equipment or cold/ chilled water with absorption chillers. Potential for using tri-generation systems has been identified to be nearly 500 to 1,000 MW in India. Tri generation technology, also known as Combined Cooling, Heating, and Power (CCHP), comprises of a gas engine or a power system operated by burning waste, bio fuel, or fossil fuel to produce electricity. The connected heat recovery system is used as a heat exchanger to recover heat from the engine or exhaust. This recovered heat can be used for heating applications like hot water or a regeneration process in absorption chillers. The electricity produced within the tri-generation process could be used to meet the building loads or power chillers during peak load period.  The thermal energy could be diverted to boilers to heat the water used in hospitals, hotels, and industries for numerous purposes and/ or to absorption chiller to heat the absorbent and refrigerant mixture and regenerate the absorbent.

15. solar air conditioning system Typically vapor absorption machines or chillers are used in solar conditioning. Energy is saved by using the heat generated from the solar panels to regenerate the absorbent in the chiller. Absorption chillers comprise of the following components: Evaporator: where the refrigerant evaporates at a very low pressure and temperature and is absorbed by the absorbent. The process results in extraction of heat from the refrigerant and provides chilled refrigerant as an output. Generator: The mixture of absorbent and refrigerant is then introduced in the generator. Steam or hot water produced through the solar panel devices is used to vaporize refrigerant. Condenser: The vaporized refrigerant will be cooled down in condenser and maintained at low pressure. This cooled refrigerant will be further used in evaporator for generation of chilled water for air conditioning.

16. Radiant cooling system Pipes embedded in the structure cool or heat the thermal mass of the building generally during the hours when it is unoccupied. For cooling, radiant systems use both thermal mass and nocturnal cooling. Chilled water in the pipes can be supplied through a conventional chiller.

17. Guiding principle of a conventional air conditioning system is convection whereas in a radiation system, the guiding principle is heat transfer through radiation. Heat transfer predominately occurs through surfaces like floors, ceiling, or wall which in turn are heated or cooled by embedded coils. Radiant systems are installed in combination of large thermal mass to facilitate absorption and radiation. For optimizing performance of the systems, coils should be installed in floors for heating purposes, and in ceiling for all cooling purposes. Application of radiant systems is limited to areas which have high latent load and chances of air leakage from humid areas are high. Improperly installed systems can lead to condensation on the building structural elements. Types of radiant cooling Chilled slabs: These deliver cooling through the building structure, usually slab, and are also known as thermally activated building systems. Ceiling panels: These deliver cooling through specialized panels. Systems using concrete slabs are generally cheaper than panel systems and offer advantage of the thermal mass while panel systems offer faster temperature control and flexibility. Capital expenditure of this system is the same as a high efficiency chilled water system; however, operational expenditure is less than the chilled water system. Radiant cooling systems consist of coils embedded within the structure. These coils carry chilled water generated either through conventional electric chiller systems or low energy chilled water generation systems like absorbent chillers, desiccant chillers. Chilled water in the coils cools down the slab or panels which in turn act as heat sinks for sensible heat loads of internal spaces. Concrete structures typically used with radiant cooling systems also increase the thermal mass of buildings.  This introduces inertia in the structure against temperature fluctuations and allows it to absorb heat from internal spaces.

18. Heat recovery ventilator (HRV) Rotary enthalpy wheel Fixed plate Heat pipe Run around coil Thermosiphon Twin towers

19. Ground source heat pumps Ground source heat pumps use the earth as a heat sink if a building is to be cooled and as a heat source if a building is to be heated. Temperatures at a certain depth from the surface are nearly constant through the year, and this temperature differential is utilized by the heat pumps to cool or heat the refrigerant in a conventional vapour compression cycle.

20. Shared ground heat exchange can deliver low-carbon electrified heat where individual heat pumps or heat networks are not feasible, such as in terraced homes. However, there is a policy gap around these mid-scale heat solutions. We outline the benefits and challenges of shared ground heat exchange, and actions needed by policy, housing, and innovation stakeholders to support further deployment.

21. A Ground Source Heat Pump (GSHP) system heats and cools building by using earth as a heat source or heat sink. The system either extracts thermal energy out of the ground or transfers thermal energy from buildings to the ground. Moreover, heat energy stored during the summer season could be extracted out during winters to heat the ambient spaces. On average, 46% of the total solar energy received is stored. At 4-6 meters below ground surface, temperatures are more or less constant. Heat could be pumped in during summers to the ground, where the temperature is lower than the ambient temperature. GSHP system has three major components: Earth Connection: Earth connection is the connection between the GSHP system and the soil.  Most popular connections are tubes, introduced either horizontally or vertically into the ground, or submerged in a lake or pond. The tubes carry an anti-freeze mixture and a suitable type of heat transfer fluid. Heat pump: Heat pump helps heat transfer from fluid in the earth connection to the distribution system. The heat pump consists of a heat carrier like water or air, which absorbs heat from heat transfer fluid through indirect contact and subsequently carries this heat energy to the heating/ cooling distribution system. In a reverse cycle, the heat carrier transfers heat from the distribution systems to the heat transfer fluid in the earth connection. Heating/ cooling distribution system: This system delivers the heating or cooling from the heat pump to the ambient spaces. It consists of air ducts, diffusers, fresh air supply systems and control components, and circulates the supply air as per design conditions and occupants requirements. Depth below ground surface where temperatures are nearly constant is valid for India. It varies by latitude.

22. Renewable energy systems

23. The process of generation of electricity from solar cells is a two – step process. The first step is the physical process and involves the photoelectric effect in which the photons strike the metal surface and provide energy to the electrons in the metal. The next step involves the electrochemical process in which the excited electrons are arranged in a series, thereby creating an electric voltage and generating electric current. The generated electricity can either be consumed instantaneously on site, stored in batteries for later use, or sold to power utilities according to local government regulations and prevalent tariffs.

24. Solar Energy Deployment Based on the availability of space and capital, solar energy can either be generated offsite at utility level, or onsite at small scale. Both types of generation mechanisms are guided by their own rules and policy frameworks. Utility driven solar project development  – These are large scale centralized solar power plants which generate electricity to be sold to power utilities. These plants require large tracts of land and considerable capital. These plants usually have a long term Power Purchase Agreement (PPA) with the power utility and usually serve to fulfil their Renewable Purchase Obligations (RPO). Customer driven solar project development  – These are small scale decentralized solar power plants installed by electricity consumers in their own premises. These type of projects require less area and capital investment. These systems are further divided into two parts: Grid Connected Systems  – Grid connected PV systems are designed to work in conjunction with the utility grid. Such systems can either supply the complete generated electricity to the grid or can use the electricity for building use and supply only the excess power to the grid. Stand – alone systems  – Stand – alone PV systems are designed to operate within the context of the building and are not connected to the grid. The electricity generated is consumed by the building and excess energy generated can be stored in the batteries for future use.

25. Solar electricity generation system A complete solar electricity generation system consists of components to produce electricity, convert generated DC into AC that can be used by equipment installed in the building, and store excess generated electricity (for those systems which do not intend to sell excess generated electricity to grid). Solar PV panels  – Solar panels are the basic part of a solar electricity generation system. These panels consist of numerous solar cells which are made up of a semiconducting material. These solar cells are responsible for conversion of incident light into usable electricity. Although the sizes may vary according to generation capacity, location and budget, the typical length of the solar panel ranges between 65 inches and 77 inches and the breadth ranges between 35 inches and 39 inches. The typical depth of solar panels ranges from 1.4 inches to 1.8 inches. Inverter  – The inverter converts the DC produced by the solar panels into AC that can be fed into the grid or used for the operation of electrical appliances. Additionally, the inverter acts as a safety valve between the PV system and the electricity mains. Storage Batteries  – Storage batteries are used to store excess electric energy generated by the PV system for future use. Batteries are typically employed in PV systems which do not intend to sell excess electricity to power utilities. Electricity Meter  – The meter counts the number of units of electricity generated by the PV system. They are essential for calculating the proceeds from the sale of electricity to the grid.

26. Factors affecting generation of electricity Solar cell efficiency is the ratio of electrical output to the incident solar energy. Major factors efficiency of solar cells are: Location, tilt, and orientation  – The incident solar radiation varies significantly with longitude and orientation. Within a particular longitude and orientation, maximum solar radiation is available in a particular tilt angle based on sun path. Over shading  – Site characteristics like geography, neighbouring buildings, self-shading, cloud factors etc. affect the useful solar radiation falling on the PV panels. System design should be done to minimize panel area affected by shading. Temperature  – An increase in panel temperature due to solar radiation can affect the PV module performance especially in crystalline silicon modules. It is estimated that for every 1  C increase in ambient temperature above 25  C, the PV module performance decreases in the range of 0.4 – 0.5%. Special considerations are given to design air flow over the backs of the PV modules to avoid higher temperature by excessive heat gains. Panel efficiency  – Panel efficiency is an estimate of successful conversion of incident solar radiation to electric energy. Panel efficiency depends on PV module technology, manufacturing techniques, and system design. A crystalline silicon based module has an efficiency in the range of 12-14% where as a thin film based module has an efficiency in the range of 10 – 11%.

27. Wind power is generated by using wind turbines to harness the kinetic energy of wind. Wind blowing across the rotors of a wind turbine causes them to spin. The spinning of rotors converts a portion of the kinetic energy of the wind into mechanical energy. A generator further converts this mechanical energy into electricity. Wind power can be generated at utility scale, offshore location and at distributed or small scale.  Utility scale wind power  uses turbines larger than 100 kilowatts to deliver power to the grid.  Offshore wind power , as the name implies, is generated by installing large turbines at offshore locations.  Distributed wind power  is produced from turbines of 100 kilowatts or less and supply power directly to a home or building or for running any machine.

28. Horizontal axis wind turbines (HAWT) continually face in the direction of wind and are  lift driven  machines. Rotors in a HAWT can be in front of the tower on which it is supported and facing the wind (windward), or behind it and away from the wind (leeward). Rotors or blades in most horizontal axis turbines are placed upwind to the tower. Horizontal wind turbines are equipped with sensors which determine both the direction and velocity of the wind. Number of rotors may vary but 2-3 rotors are the most efficient configuration and most easily available. Vertical axis wind turbines (VAWT) are not dependant on the wind direction and are more suitable for area of highly variable wind direction. Shaft containing the gearbox, generator etc. is vertical. Consequently they are more suitable for distributed generation in buildings.  Generator and gearbox is installed on the ground for vertical turbines which renders them easier for maintenance.  Darrieus  or egg beater is a lift force driven vertical axis turbine and  Savonius  is a drag driven type of vertical axis turbine. Savonius wind turbines are the most widely used drag type turbines because of their robustness.

29. Biomass energy is the energy obtained from plants or plant-derived materials. Wood is the most widely used source of biomass energy. Other sources of biomass include: terrestrial and aquatic plants, agricultural wastes, industrial residues, sewage sludge, animal and municipal wastes. There are three major technologies used for conversion of biomass into useful energy:

30. Biomass Gasification In this, a thermo-chemical process is used to convert biomass to producer gas. Producer gas is a mixture of Carbon monoxide (CO), Hydrogen (H 2 ), Methane (CH 4 ), Carbon dioxide (CO 2 ) and Nitrogen (N 2 ). The sources of biomass in this include wood and its products as well as various agricultural residues. Upon gasification, this can lead to power generation in the range of 10 kW – 1000 kWe . The energy produced can also be used for thermal application in small industries up to 3 MW. Biogas In this, Bio-methanation process is used to convert biomass to biogas. Animal dung is commonly used in production of biogas. The Biogas produced can be used for cooking in households as well as for electricity generation. Biofuels The process of trans-esterification is used for production of bio-diesel. Bio-oil is also extracted from oil seeds. The source for biofuels is non edible vegetable oil seeds. Biofuels are used for electricity generation as well as motive power. The use of biomass energy greatly reduces dependence on fossil fuels. The products used for conversion of biomass to energy are abundant in nature and the energy is renewable in nature. Biomass being a clean energy resource receives various tax benefits from the government.