Upgrading the Smartness of Retrofitting Packages towards Energy-Efficient Residential Buildings in Cold Climate Countries: Two Case Studies

Laurina Felius,Mohamed Hamdy,Bozena Hrynyszyn,Fredrik Dessen

doi:10.3390/buildings10110200

Laurina Felius, Mohamed Hamdy + Show 2 more

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https://doi.org/10.3390/buildings10110200

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Journal: Buildings	Publication Date: Nov 3, 2020
Citations: 14	License type: CC BY 4.0

Affiliation: Norwegian University of Science and Technology

Abstract

Improving the energy efficiency of existing buildings by implementing building automation control strategies (BACS) besides building envelope and energy system retrofitting has been recommended by the Energy Performance of Buildings Directive (EPBD) 2018. This paper investigated this recommendation by conducting a simulation-based optimization to explore cost-effective retrofitting combinations of building envelope, energy systems and BACS measures in-line with automation standard EN 15232. Two cases (i.e., a typical single-family house and apartment block) were modeled and simulated using IDA Indoor Climate and Energy (IDA-ICE). The built-in optimization tool, GenOpt, was used to minimize energy consumption as the single objective function. The associated difference in life cycle cost, compared to the reference design, was calculated for each optimization iteration. Thermal comfort of the optimized solutions was assessed to verify the thermal comfort acceptability. Installing an air source heat pump had a greater energy-saving potential than reducing heat losses through the building envelope. Implementing BACS achieved cost-effective energy savings up to 24%. Energy savings up to 57% were estimated when BACS was combined with the other retrofitting measures. Particularly for compact buildings, where the potential of reducing heat losses through the envelope is limited, the impact of BACS increased. BACS also improved the thermal comfort.

Highlights

One of the key strategies towards an energy-efficient building stock is retrofitting, especially of residential buildings, which have a considerable energy-saving potential
The associated difference in life cycle cost, compared to the reference design, and thermal comfort were calculated for each optimization iteration
3031 input values, which resulted in a total energy consumption of 149.8 kWh/m2 year, i.e., 8% higher than for the representative apartments

Summary

Introduction

One of the key strategies towards an energy-efficient building stock is retrofitting, especially of residential buildings, which have a considerable energy-saving potential. Effective retrofitting measures and achieved savings are climate-specific, and this paper concentrates on retrofitting the residential building stock in cold climate countries, i.e., Norway. Most of the literature on cold climate retrofitting of dwellings focuses on improving the energy efficiency through retrofitting the building envelope and energy systems, as pointed out by Felius et al [1]. Another category of retrofitting measures that has potential to decrease the energy consumption, though less often mentioned, is building automation control systems (BACS). BACS can be attractive retrofitting measures, especially when the other energy performance requirements, such as the exterior wall U-value, cannot be improved due to, for example, space restrictions or financial constraints

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