Optimization of Passive Envelop Energy Efficient Measures for Office Buildings in Different Climate Regions of China Based on Modified Sensitivity Analysis

Abstract

With the growing desire for new buildings and better indoor comfort, the amount of energy consumption of office buildings in China is increasing rapidly, which will lead to the great challenge for energy supply and sustainable development. Building passive envelop energy efficient measures (PEEEMs), mainly including exterior wall insulation, roof insulation, different glazing types, and shading system, were widely applied. However, the specific energy efficient performance of PEEEMs was various in different climate conditions that have not been evaluated clearly yet. The priority order of PEEEMs was not recommended in relative standards. The economic benefits cannot be considered synchronously with PEEEMs optimization. This paper modified the sensitivity analysis to fit the building energy efficiency evaluation. By combining the modified method with a simulation tool, the energy efficiency and economic effects of PEEEMs of office buildings in various climate regions can be considered at the same time. Four case buildings in Shenyang, Tianjin, Ningbo, and Shenzhen were proved to reach the energy-saving potentials of 9.44%, 7.75%, 20.87%, and 13.27% respectively, with the payback period of no more than 1.5 years. Finally, the recommended application priority rankings and the recommended ranges of thermal performance properties of PEEEMs in the four typical climate regions were presented.

A Study on Energy-Saving Technologies Optimization towards Nearly Zero Energy Educational Buildings in Four Major Climatic Regions of China

“…However, the low U-value of external walls in Guangzhou prevents heat dissipation in summer, causing the indoor temperature to be too high. The cooling and total energy consumption increase slightly with the decrease of U-value of external walls, which means this technology should be carefully chosen in HS/WW region, and this conclusion is also supported by [14]. The roof is another part of the building envelope, and the optimization analysis method is similar to the exterior walls.…”

“…There are two kinds of patterns widely adopted for dealing with indoor thermal comfort. One is considering the comfortable indoor environment as a precondition in energy efficient buildings, and the other is taking the indoor air quality as an influencing factor of building energy consumption and exploring the quantitative relationship [14]. In this paper, natural ventilation mainly occurs at night in summer or in transition season.…”

“…Moreover, the study of energy-saving technologies in this paper were in conformity with the first pattern, which takes comfortable indoor parameters as fixed values ( Table 1). The setpoint of indoor temperature in the room is 26 • C in summer and 20 • C in winter, and can achieve the comfort indexes of PMV ≤ 0.5 and PPD ≤ 20% [14]. Therefore, energy savings of these technologies would not compromise thermal comfort.…”

“…The results showed that about 42% energy can be saved by the office building designed with high-performance envelope. In addition, the optimization on high-performance office building facades also has been done by Pikas et al [40] and Wang et al [14], and their research results all indicated that the high-performance envelope has an important contribution to building energy conservation. Through dynamic monitoring, Rey-Hernandez et al [41] analyzed the role of renewable energy (photovoltaic system, earth-to-air heat exchanger, biomass boiler) in buildings and the applicability of these energy efficiency policies in the construction of nZEBs.…”

“…Therefore, improving the performance of the building envelope is significant to optimize the building energy-saving design. Wang et al [14] discussed the influence of external walls and roofs with different heat transfer coefficient (U-value) on building energy consumption, and found that appropriate improvement of envelope performance had significant energy-saving effect on building energy conservation. Touloupaki et al [15] optimized the insulation thickness of the external envelope to determine the optimal insulation thickness by measuring the primary energy demand and cost of the building, and they found that the U-value of the building elements decrease and cause highest energy savings (75%) before 11-15 cm of insulation.…”