Sustainable Engineering

Although effective alternative energy sources that do not release harmful gases such as CO2, Sox, NOx, etc. are increasingly being used, fossil fuels continue to be consumed. Equipment and systems that are energy efficient, use less fuel, reduce the consumption of fossil fuels and the production of greenhouse gases and other pollutants are of paramount importance. Design and installation of facilities and systems can play a major role in stemming the increasing dangers to the global environment. Waste heat recovery and thermal storage (ice or water) are examples of such systems designed by PTM. 

●Electric power and stored energy

Electricity demand trends indicate consumption increases from year to year, leading power generation companies to consider increasing their capacities. However, there are high capital costs and environmental impacts, which are of concern. If electricity demands could be spread more evenly between the peak and off-peak times, and the peak demand reduced, the need for new power plants would not arise. Storing electricity is difficult however, if this excess electrical capacity can be stored as energy in a form such as hot water or ice, and this energy then be used for air conditioning etc. during the day, then the demands during peak times will be reduced. The power required for cooling and heating may amount to 15 to 20% of the total building energy consumption. In other words a 15 to 20% reduction in the peak power demand is achievable. Furthermore off-peak power charges are around 1/4 of the peak costs, thereby producing cost savings. By using stored energy for air-conditioning, electrical consumption can be reduced and a major contribution can be made to environmental protection.

●Total Energy System

Data measured from one case can provide the following explanation on the impact of a co-generation system(CGS). Firstly, total power, power received and power generated is indicated for the week from 13th March to 19th March. While the power received peaks change daily in accordance with the building usage, the CGS runs as per plan with the received power during the day time being minimized. The next graph shows the monthly CGS thermal efficiency, thermo-electricity comparison, steam usage efficiency, hot water usage efficiency, efficiency of electricity generated and net working rate. Even during the March to May period when efficiency tends to decrease, there is no significant drop and efficiency for the overall period reaches 70.5%. For cooling, it was possible to have the CGS exhaust heat recovery absorption refrigerator cover 45% of the loads being produced. Finally, the annual primary energy usage is shown. The figure of 2,048MJ/m2 represents a drop of 26% compared to similar buildings. In this way, CGS power generation and exhaust heat recovery can be used to achieve a high level of energy conservation.