Simplified Method of Optimal Sizing of a Renewable Energy Hybrid System for Schools

Abstract

Schools are a suitable public building for renewable energy systems. Renewable energy hybrid systems (REHSs) have recently been introduced in schools following a new national regulation that mandates renewable energy utilization. An REHS combines the common renewable-energy sources such as geothermal heat pumps, solar collectors for water heating, and photovoltaic systems with conventional energy systems (i.e., boilers and air-source heat pumps). Optimal design of an REHS by adequate sizing is not a trivial task because it usually requires intensive work including detailed simulation and demand/supply analysis. This type of simulation-based approach for optimization is difficult to implement in practice. To address this, this paper proposes simplified sizing equations for renewable-energy systems of REHSs. A conventional optimization process is used to calculate the optimal combinations of an REHS for cases of different numbers of classrooms and budgets. On the basis of the results, simplified sizing equations that use only the number of classrooms as the input are proposed by regression analysis. A verification test was carried out using an initial conventional optimization process. The results show that the simplified sizing equations predict similar sizing results to the initial process, consequently showing similar capital costs within a 2% error.

Techno-Economic Feasibility of a Grid-Connected Hybrid Renewable Energy System for a School in North-West Indonesia

“…Figure 7a shows that most of the load can be compensated by the renewable power (upper line) generated from the optimal configuration for this scenario (only 2.82% of the generated power were consumed by the school and the rest 97.2% were sold back to the grid). This corroborates the findings reported in a previous study [12], which stated that the RES installation at a school is suitable in accordance of its energy demand profile and condition of the location.…”

“…Schools, having their activities largely limited to daylight hours, offer a unique opportunity to deploy renewable energy system dependent on daylight hours to meet the majority of their electricity demand profile [12].…”

“…Another study mainly focused on optimization of several HRES components to compensate for the heating and electricity demand of a school building in South Korea [12]. A study assessing the viability of HRES in a school building in Greece found that the installation could provide mitigation of climate change, resources protection, costs reduction, and energy saving [16].…”

Optimal Decision-Making of Renewable Energy Systems in Buildings in the Early Design Stage

“…These previous studies made detailed performance simulations to determine optimal designs, but such methods are not easy to use in the early design stage. To overcome this problem, Kim & Kim proposed an optimal sizing method for RES for school buildings based on simplified sizing equations [56]. While this study is suitable for school buildings, it is difficult to apply to other building types.…”

Optimal Operation of a Grid-Connected Hybrid Renewable Energy System for Residential Applications

“…For example, studies have been published on hybrid renewable energy systems [6] involving two main energy technologies, such as solar-fuel cell systems [7], solar-biofuel systems [8], solar-battery systems [9], solar-thermal-PV systems [10], solar micro-generation systems [11], PV-wind systems connected to the electrical grid [12], solar-wind systems for remote regions [13], and wind-fuel cell systems [14]. Results have also been reported for hybrid renewable energy systems involving three primary energy technologies.…”