Energy-saving retrofits of prefabricated house roof in severe cold area

The roof is the most significant in the energy consumption of building envelopes in severe cold area. The poor thermal performance of the prefabricated house roof leads to the increase in heating energy consumption and an uncomfortable indoor thermal environment. The purpose of this study is to explore the energy-saving retrofit technology of prefabricated house roof from the perspective of structure, energy-saving and economic feasibility. It is the innovation to put forward the capping form of pre-fabricated house roof and compare the thermoeconomy of various roof forms and thermal insulation materials. Using EnergyPlus software, the energy consumption of a typical prefabricated house with flat, slope and capping roof with insulation ceiling in severe cold area is simulated. The life cycle cost of these retrofit cases is estimated. The three-level comparisons between flat roof and slope roof, capping roofs at different angles and thermal insulation ceiling are quantitatively analyzed. The results show that the capping roof is the most energy-saving, the flat roof is the second, and the sloping roof is the worst. The capping roof 10 degrees double slope +200 mm RW ceiling insulation is the optimal retrofit scheme, and the energy-saving rate reaches 19.38%. It significantly reduces heating energy consumption, operating costs, carbon emission, and improves the indoor temperature during the heating period and stabilizes the indoor temperature fluctuation. The roof retrofit measures of prefabricated houses have full energy-saving potential and practicability. (C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

The roof is the most significant factor in energy consumption of building envelopes in severe cold areas, and the poor thermal performance of prefabricated house roofs leads to increased energy consumption and discomfort in indoor thermal environment. This study explores energy-saving retrofit technologies for prefabricated house roofs from the perspectives of structure, energy-saving, and economic feasibility. The capping form of prefabricated house roofs and the thermoeconomy of various roof forms and insulation materials are compared. Simulation results using EnergyPlus software reveal that the capping roof is the most energy-saving, followed by the flat roof, while the sloping roof performs the worst. The optimal retrofit scheme is a capping roof with 10 degrees double slope and 200 mm RW ceiling insulation, achieving an energy-saving rate of 19.38%. It significantly reduces heating energy consumption, operating costs, carbon emissions, improves indoor temperature during the heating period, and stabilizes indoor temperature fluctuation. The roof retrofit measures for prefabricated houses have great energy-saving potential and practicality.