Modeling Energy Efficiency Performance and Cost-Benefit Analysis Achieving Net-Zero Energy Building Design: Case Studies of Three Representative Offices in Thailand

Kittisak Lohwanitchai,Daranee Jareemit

doi:10.3390/su13095201

Abstract

The concept of a zero energy building is a significant sustainable strategy to reduce greenhouse gas emissions. The challenges of zero energy building (ZEB) achievement in Thailand are that the design approach to reach ZEB in office buildings is unclear and inconsistent. In addition, its implementation requires a relatively high investment cost. This study proposes a guideline for cost-optimal design to achieve the ZEB for three representative six-story office buildings in hot and humid Thailand. The energy simulations of envelope designs incorporating high-efficiency systems are carried out using eQuest and daylighting simulation using DIALux evo. The final energy consumptions meet the national ZEB target but are higher than the rooftop PV generation. To reduce such an energy gap, the ratios of building height to width are proposed. The cost-benefit of investment in ZEB projects provides IRRs ranging from 10.73 to 13.85%, with payback periods of 7.2 to 8.5 years. The energy savings from the proposed designs account for 79.2 to 81.6% of the on-site energy use. The investment of high-performance glazed-windows in the small office buildings is unprofitable (NPVs = −14.77–−46.01). These research results could help architects and engineers identify the influential parameters and significant considerations for the ZEB design. Strategies and technical support to improve energy performance in large and mid-rise buildings towards ZEB goals associated with the high investment cost need future investigations.

Highlights

Rising global energy demand is a serious concern in several countries.In Thailand, the final energy consumption in the building sector accounts for 23% of the national energy consumption [1]
Increments of investment costs are a significant barrier to achieving the zero energy buildings level (ZEB) design for office buildings in Thailand
This study suggests that either decreasing energy consumption or generating more renewable energy for office buildings in Thailand should be reconsidered to achieve the Making the nearly zero energy buildings to be zero consumption, higher energyefficient designs and technologies should be applied

Summary

Introduction

Rising global energy demand is a serious concern in several countries.In Thailand, the final energy consumption in the building sector accounts for 23% of the national energy consumption [1]. Energy consumption in the commercial sector will suddenly increase and be higher than in other sectors Such an increment of energy demand will make the country face energy shortages, high energy prices, and an increase in pollutants and CO2 emissions. Regarding this concern, the Department of Energy of Thailand has enforced the Energy Conservation Promotion. Three higher energy efficiency standards were defined in the Thailand 20-Year Energy Efficiency Development Plan (2011–2030) to lessen the final energy use by 17% in 2030 [2] These standards comprise (1) higher energy performance standard level (HEPS), (2) economic level (ECON), and (3) zero energy buildings level (ZEB), with the aim being to reach the ZEB in 2037

Methods

Results

Discussion

Conclusion