Review on Various Techniques of Energy Conservation for Thermal comfort

One of the Crucial objectives of sustainable design is Energy saving. Along with saving energy, creating the best comfort inside the interior has utmost importance. One of the key strategies to reduce energy consumption is recognized as day lighting, which reduces the usage of artificial lighting inside the building. The introduction of daylight into the interior has positive effects on productivity and health of the occupant. On the other hand, excessive sunlight inside will cause thermal and visual discomfort. Incorporating daylight into a building design has been recommended for green building rating systems and Energy standards [1].The factors which influence the needs of the building energy include sunlight, temperature, and perspiration. These factors vary with season, location as well as orientation of a building and the time of the day. As the previous studies day lighting is always be great strategies for the excellent and high performance for buildings which are sustainable. It is also providing big advantages for the area environment and good lighting space. It is just not committed to low maintenance only with the small energy consumes but it is making a comfortable zone for working area. In the recent years, the growth in Information Technology is responsible for the rise in Energy uses in office buildings. In an office building, two-third of all the energy consumed is due to lighting, equipment inside the office as well as Heating Ventilation and Air Conditioning (HVAC). In the present age with diminishing natural resources, the energy efficiency can be improved introducing daylight into the interiors. Even in the modern offices, the daylight entry is very important, not only from the energy efficiency but also ―for majority of occupants the window remains that vital link with the outside world‖ [2].Lighting accounts for over a quarter of the total energy usage in commercial buildings. LED is found out to be the best solution, since the heat output from the LED is negligible. The adoption of energy-saving LED lighting technology is one way to reduce the costs, but clearly even greater savings are possible by turning lights OFF when not needed, and optimizing light levels to suit the working environment and the task in hand. Suitable controls are the key to reduce energy consumption for commercial buildings particularly. This requires a baseline of automatic controls. Having established a framework of automatic controls, there will always be a requirement to override default conditions with manual switches/dimmers, remote controls or through access to the programming system [3]. Energy Informatics can be known as ―designing, analyzing & developing systems to increase performance of energy need & transmission systems‖. This means that the energy consumption

responsible for excessive heat penetration and hence overheating [5].Energy can be saved by properly selecting window coverings or treatments. The Window treatments can also reduce heat gain in summer and heatless in winter. The Window treatments which can reduce heat loss in summer include Vertical or Horizontal slat type and Window blinds and they can block the direct sunlight into the interiors [6]. The introduction of shading devices can significantly reduce the cooling demand and hence the load on the HVAC. The shading devices, in turn, will protect the façade from direct insulation [7]. Automated shading devices rotate according to the comfort needs and the weather conditions. Temperature and luminance sensors are used to give commands to the shading devices. A carefully positioned shading system will control the entry of daylight and hence substitutes the artificial light with the daylight [8]. ―The situationsof mind which shown the need with Thermal environment‖ is referred to as Thermal Comfort. This varies from person to person both physiologically and psychologically. Hence, it is difficult to describe the thermal environment that would satisfy everyone. However, the conditions are defined where a specified percentage of occupants would feel thermally comfortable. The six initial elements viz., radiant temperature, air temperature, humidity, metabolic rate, clothing insulation & air speed need to be addressed while defining the thermal comfort. All the above factors vary with time [9].The Thermal comfort can be achieved with thermal balance, where the inside heat produced in the body is equal to the heat lost to the environment. If the weather is too hot or too cold it can cause thermal dissatisfaction [10]. In order to maintain the thermal comfort levels of the occupants, most of the energy is greatly utilized to heat, cool & control humidity in space. The energy demands can be reduced by utilizing advanced materials, which improve environmental impact [11]. ―The ability of a person to carry out any task comfortably in terms of his/her photo-sensory perception‖ is known as Visual Comfort. The various factors on which the Visual comfort depends are the direction of light source, the light intensity, the contrast of surfaces, the reflection of surfaces, photo-sensory response of the eye and the nature of the task being undertaken [12]. The minimum level of luminance required to provide visual comfort for various tasks and locations is specified by International recommendations. The Visual comfort can be achieved by maintaining the recommended luminance level avoiding glare. Happiness and productivity of the users of a building can be enhanced by providing the right mixture of air speed, temperature, and humidity. Since everyone has his/her own criteria for comfort, it is usually measured by the percentage of occupants who are satisfied with the prevailing condition [13]. The as well as visual comfort has to be achieved. The main intention of the intelligent system is to continuously satisfy the occupants in terms of comfort followed by reducing the energy consumption. The earlier studies have proved that the energy performance of any building with lighting controls and automated window blinds is superior to those with the static blind system [14].Movable shading devices prevent the building from overheating as well as provide thermally and visually comfortable environment. The control strategy adopted and the choice of the system are influenced by many parameters. The studies carried out so far, have investigated the influence on energy demand considering either the thermal comfort or the visual comfort at a time. Only a few of them have considered both the visual and the thermal comfort into account [15].

This section present the previous studies which is done by several authors in selected subject, we referred several researches for this study. In [1] studied the effectiveness of day lighting through simulation of a typical office floor at Dhaka City. The significance of light shelves was highlighted pertaining to daylight entry. It was proved that among the seven alternatives studied, light shelves at a height of 2m above floor level performed better to achieve the required light levels. Energy consumption in an office building can be reduced by integrating artificial lighting with daylight. In [2] carried out a simulation study for organizational buildings in the tropical climate of Batu Pahat in Malaysia to find the thermal performance. This was followed by validation with measured data. The discrepancy was less than 10% that indicated a good agreement. It was found that direct solar radiation influenced the heat gain in a building. In [3] an important strategy for thermal as well as visual comfort is the proper use of shading. Some of the shading strategies are overhangs, louvers and vertical fins. These shading strategies can be external or internal as well as fixed or adjustable. While designing these elements, both the thermal and the visual comfort need to be considered simultaneously. The heat and glare of direct sun entering through the windows can be avoided using the shading devices. In [4] Energy consumption from artificial lighting can be reduced introducing shading system, which in turn improves the visual comfort of the occupant. An automated system which operates by sharing the information will provide the maximum comfort and is energy efficient. The actual occupancy data of the and electric demand. In [5] explained the computer based analysis and design techniques to create environmental simulation models on which the thermal comfort ranges and air conditioning loads in a residential house were predicted. In [6] used Matlab/Simulink to implement normal building HVAC method. This system predicted the temperature change into building & estimated the amount of energy which is wants to achieve comfort level. The location of building, inside properties of the building, gains & heating system as well as weather were considered for estimation. This model has the advantage of its less computational resources and its simplicity. In [7] showed that human thermal comfort is not reflected adequately by only PMV. In order to reflect human thermal comfort in an interior, the humidity control is very important. The range of humidity for human comfort is between 30 % and 60%. In [8] specified that for the occupant to be satisfied with the environment, both the thermal and the visual comfort have to be achieved. By reducing cooling loads i.e. avoiding additional energy consuming devices for cooling, the thermal comfort can be achieved. For optimization, the building simulation software tools can be used. In [9] optimized the design of passive buildings using the simulation through an approach which is comfortable. Solar shading that plays a very important role in Tropical climate has been emphasized. The solar shades are developed depending on the availability of daylight inside the room and the percentage of thermal comfort required. In [10] focussed on achieving visual comfort and energy saving integrating day-light & artificial light in hot temperature humid climate. The visual performance & energy saving were predicted for three kinds of various glazed windows. A good amount of decrease in cooling & building energy conservation has been analysed for all types of glazing.

Following table shows the related studies of this paper

An extensive review of the research work was carried out in the area of Energy Conservation for Thermal comfort, energy conservation and adaptive controllers. Although some works have been reported in the area of thermal and visual comfort, it is observed that the Energy Conservation for Thermal comfort has been given priority. Daylight

was not explored. Based on the above observations, the gaps in the earlier research are formulated as follows:

• Collaboration of thermal comfort behind in place along with due known as decrease on air conditioner load which is not explored.

• Energy saving collectedfrom given integrated approach into the area which has not been touched upon.

• Considering optimum quantity of day-light which is basis on thermal comfort need of worker, is one of the areas where next investigations are needed.

An effort is made to explore the research undertaken in the areas of day lighting, thermal comfort & energy conservation. A dynamic window blind controller that can significantly lower the energy consumption while providing the ideal living and working circumstances, which, in turn, lead to more well-being of the occupant is the need of the hour. From the survey of the previous work undertaken, the area that has not been analyzedso far is taken up in this research work. The challenge is to lower the energy consumption by increasing the comfort within the building with one integrated solution. Hence, this work concentrates on developing a dynamic method giving the higher priority to thermal comfort energy conservation. Finally, the system developed is proved to be energy efficient.

1. Akhtar Firoz, Patil Pramod B, (2014) Performance of FPGA for Home Automation using VHDL, International Journal of Science and Research (IJSR), Volume 3 Issue 7, 2. Álvarez J. D., Redondo J. L., Camponogara, E., Normey-Rico, J., Berenguel, M., & Ortigosa, P. M. (2013). Optimizing building comfort temperature regulation via model predictive control. Energy and Buildings, 57, 361-372. 3. Biery E., Shearer T., Ledyard R., Perkins, D., & Feris, M. (2014). Controlling LEDs.Technical white paper by Lurton Electronics Co. 4. Debono C. J.& Abela K. (2012). Implementation of a home automation system through a central FPGA controller. InElectrotechnical Conference (MELECON), 2012 16th IEEE Mediterranean (pp. 641-644). 978-1-4673-0784-0/12/©2012 IEEE. comfort in hot climates. Energy and Buildings, 108, 307-316. 6. Freewan A. (2014). Impact of external shading devices on thermal and day lighting performance of offices in hot climate regions. Solar Energy, 102, 14-30. 7. Giarma C., Tsikaloudaki K., &Aravantinos D. (2017). Day lighting and Visual Comfort in Buildings‘ Environmental Performance Assessment Tools: A Critical Review.Procedia Environmental Sciences, 38, 522-529. 8. Grynning S., Time B., & Matusiak B. (2014). Solar shading control strategies in cold climates–Heating, cooling demand and daylight availability in office spaces. Solar energy, 107, 182-194. 9. WangS.& Yu D. (2012). Remote monitoring and controlling system based on ZigBee networks. International Journal of Software Engineering and Its Applications, 6(3), 35-42. 10. Karmacharya S., Putrus G., Underwood C., & Mahkamov K. (2012). Thermal modelling of the building and its HVAC system using Matlab/Simulink. In Environment Friendly Energies and Applications (EFEA), 2012 2nd International Symposium on (pp. 202-206). 11. Giarma C., Tsikaloudaki K., & Aravantinos D. (2017). Day lighting and Visual Comfort in Buildings‘ Environmental Performance Assessment Tools: A Critical Review.Procedia Environmental Sciences, 38, 522-529. 12. Fasi M. A., & Budaiwi I. M. (2015). Energy performance of windows in office buildings considering daylight integration and visual comfort in hot climates. Energy and Buildings, 108, 307-316. 13. Liang R., Wu Y., & Wilson R. (2015). Thermal and visual comfort analysis of an office with thermo chromic smart windows applied. In Proceedings of International Conference CISBAT 2015 Future Buildings and Districts Sustainability from Niño to Urban Scale (No. EPFL-CONF-213310, pp. 71-76). LESO-PB, EPFL 14. Mainini A. G., Bonato D., Poli T., & Speroni A. (2015). Lean strategies for window retrofit of Italian office buildings: impact on 15. Sharma S., Boddu J., Charan G. S., Sharma S., Sivanantham S., & SivasankaranK. (2015). Home automation through FPGA controller. In Green Engineering and Technologies (IC-GET), 2015 Online International Conference on (pp. 1-4). IEEE

PhD Student, Sunrise University, Alwar E-Mail –jsavita14@rediffmail.com