Optimization of the Energy System at Urban Micro Grid

Abstract

In recent years, the increasing energy demands in the residential and commercial sectors have resulted in increased carbon dioxide (CO₂) emissions ¹⁾. That is why reducing energy consumption in urban area is critically important. Therefore, it is necessary to optimize the demand for electricity and heat in both the area.

In this research, the following analysis from phase 1 through 3 were carried out to realize the sustainable energy in urban area. I show an overview of this scheme in Figure 1. First, the optimal combinations of energy saving devices to minimize the total investment cost in a hospital, hotel, office and store were clarified in phase 1. Next, minimizing cost in commercial area by area-wide energy utilization was carried out in phase 2. The purpose in phase 3 is to aim the peak cut at urban area by interchanging oversupplied energy between a residential area and commercial area. In daytime, surplus power is generated because people in residential area move to commercial area. Therefore, sending surplus power to commercial area can reduce electric demand at the area.

This paper report results about reducing the total investment cost and CO₂ emissions. As the result, the total investment cost become the minimum when gas boiler, hot water absorption chiller heater, and gas engine are introduced in hospital and hotel. On the other hand, the total investment cost become the minimum when latent heat recovery type water heater and electric heat pump are introduced in office and store. The system as above is defined to optimal system. Table 1 shows the results about energy saving ratio, running cost reduction ratio, CO₂ emission reduction ratio, initial cost reduction ratio, and repayment periods. In table 1, the optimal system is possible to reduce CO₂ emission in commercial area up to 1.6 % in comparison with standard system and payback period is 2.61 years.