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Techno-economic analysis of energy renovation measures for a district heated multi-family house.Applied Energy, http://dx.doi.org/10.1016/j.apenergy. 2016.05.104 Access to the published version may require subscription. N.B. When citing this work, cite the original published paper. AbstractRenovation of existing buildings is important in the work towards increased energy efficiency and reduced environmental impact. The present paper treats energy renovation measures for a Swedish district heated multi-family house, evaluated through dynamic simulation. Insulation of roof and façade, better insulating windows and flow-reducing water taps, in combination with different HVAC systems for recovery of heat from exhaust air, were assessed in terms of life cycle cost, discounted payback period, primary energy consumption, CO₂ emissions and non-renewable energy consumption. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump.Compared to a renovation without energy saving measures, the combination of new windows, insulation, flow-reducing taps and an exhaust air a heat pump gave up to 24% lower life cycle cost. Adding insulation on roof and façade, the primary energy consumption was reduced by up to 58%, CO₂ emissions up to 65% and non-renewable energy consumption up to 56%. Ventilation with heat recovery also reduced the environmental impact but was not economically profitable in the studied cases. With a margin perspective on electricity consumption, the environmental impact of installing heat pumps or air heat recovery in district heated houses is increased. Low-temperature heating improved the seasonal performance factor of the heat pump by up to 11% and reduced the environmental impact.

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Energy performance comparison of three innovative HVAC systems for renovation through dynamic simulation. Buildings, http://dx.doi.org/10. 1016/j.enbuild.2014.07.059 Access to the published version may require subscription. N.B. When citing this work, cite the original published paper. Energy and Permanent link to this version:http://urn.kb.se/resolve?urn=urn:nbn:se:du-15163 Energy and Buildings 82 (2014) a b s t r a c tIn this paper, dynamic simulation was used to compare the energy performance of three innovative HVAC systems: (A) mechanical ventilation with heat recovery (MVHR) and micro heat pump, (B) exhaust ventilation with exhaust air-to-water heat pump and ventilation radiators, and (C) exhaust ventilation with air-to-water heat pump and ventilation radiators, to a reference system: (D) exhaust ventilation with air-to-water heat pump and panel radiators. System A was modelled in MATLAB Simulink and systems B and C in TRNSYS 17. The reference system was modelled in both tools, for comparison between the two. All systems were tested with a model of a renovated single family house for varying U-values, climates, infiltration and ventilation rates.It was found that A was the best system for lower heating demand, while for higher heating demand system B would be preferable. System C was better than the reference system, but not as good as A or B.The difference in energy consumption of the reference system was less than 2 kWh/(m 2 a) between Simulink and TRNSYS. This could be explained by the different ways of handling solar gains, but also by the fact that the TRNSYS systems supplied slightly more than the ideal heating demand.

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