tailieunhanh - Clean Energy Systems and Experiences Part 6

Tham khảo tài liệu 'clean energy systems and experiences part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 68 Clean Energy Systems and Experiences Indoor conditions are usually fixed by comfort conditions with air temperatures ranging from 15oC to 27oC and relative humidities ranging from 50 to 70 Omer 2008 . The system performance COP is defined as the ration between the cooling effect in the greenhouse and the total amount of air input to the mop fan. Hence COP cooling delivered air input to the mop fan 4 Therefore system performance COP varies with indoor and outdoor conditions. A lower ambient temperature and a lower ambient relative humidity lead to a higher COP. This means that the system will be in principle more efficient in colder and drier climates. The effect of indoor greenhouse conditions and outdoor ambient conditions temperature and relative humidity on system performance is illustrated in Figure 16. Time h Ambient Temperature B Ambient Humidity À COP Fig. 16. Ambient temperature relative humidity and COP Conclusions There is strong scientific evidence that the average temperature of the earth s surface is rising. This is a result of the increased concentration of carbon dioxide and other GHGs in the atmosphere as released by burning fossil fuels. This global warming will eventually lead to substantial changes in the world s climate which will in turn have a major impact on human life and the built environment. Therefore effort has to be made to reduce fossil energy use and to promote green energies particularly in the building sector. Energy use reductions can be achieved by minimising the energy demand by rational energy use by recovering heat and the use of more green energies. This study was a step towards achieving that goal. The adoption of green or sustainable approaches to the way in which society is run is seen as an important strategy in finding a solution to the energy problem. The key factors to reducing and controlling CO2 which is the major contributor to global warming are the use of alternative approaches to energy generation and the .