TY - JOUR
T1 - Transforming a passive house a net-zero energy house
T2 - a case study in the Pacific Northwest of the U.S.
AU - Alajmi, Ali
AU - Rodríguez, Santiago
AU - Sailor, David
N1 - Funding Information:
The first author would like to express his gratitude to Portland State University for hosting him during his sabbatical leave. This gratitude, in particular, goes to the heads, staff, and colleagues at the Mechanical and Material Engineering Department without whom this leave would not be such a successful experience. The authors would also like to thank Ella Wong, Randy Hayslip, Rob Hawthorne, Bart Berquist, Christophe Parroco, Daeho Kang, Pamela Wallace, Stephanie Jacobsen, Steve Gross and Matt Groves for their assistance with this project. This research was supported in part by the U.S. Department of Energy under award DE-EE0003870.
Funding Information:
The first author would like to express his gratitude to Portland State University for hosting him during his sabbatical leave. This gratitude, in particular, goes to the heads, staff, and colleagues at the Mechanical and Material Engineering Department without whom this leave would not be such a successful experience. The authors would also like to thank Ella Wong, Randy Hayslip, Rob Hawthorne, Bart Berquist, Christophe Parroco, Daeho Kang, Pamela Wallace, Stephanie Jacobsen, Steve Gross and Matt Groves for their assistance with this project. This research was supported in part by the U.S. Department of Energy under award DE- EE0003870 .
Publisher Copyright:
© 2018
PY - 2018/9/15
Y1 - 2018/9/15
N2 - This paper presents the end-use energy performance analysis of the eastern unit of a duplex built based on Passive House Standard requirements in Portland, OR, USA. The energy consumption evaluation showed that this unit has 7.75, 34, 91 kWh/m2 year of heating demand, total site consumption, and primary energy consumption, respectively. A detailed energy analysis was used to explore pathways through which the house could be transformed into a net-zero energy house (NZEH). A model of the eastern unit was calibrated against measured data to perform a detailed energy analysis not only for heating energy, but also including energy used for cooling, water heater, plug loads, electric appliances, and kitchen appliances. Based on this analysis we conclude that two steps are required in order to transform a passive house into a NZEH. First, opportunities for energy conservation measures (ECMs) must be identified. In this study, changes in natural ventilation and occupant behavior were the most effective measures. Modeled implementation of these measures led to energy consumption reduction of 814 kWh/year (∼17%), and 0.1 tons of avoided CO₂/year. The second step was to investigate the most appropriate renewable energy systems; photovoltaic (PV) panels and solar water heating were evaluated. Integrating PV panels over an area of 26 m2 was sufficient to balance the remaining annual energy demand (3936 kWh/year) by producing 4053 kWh/year with a payback period of 15.4-years. On the other hand, using thermal solar water heating was found to reduce the energy consumption by 3047 kWh/year (64%); the remaining energy demand can be overcome by integrating a total of 13 m2 of PV panels. The latter approach has around a 20-year payback period and saves 0.6 tons of CO₂/year. We therefore conclude that the first approach of using PV panels is more cost-effective for transforming a passive house to a ZEH for the climate of the northwest US.
AB - This paper presents the end-use energy performance analysis of the eastern unit of a duplex built based on Passive House Standard requirements in Portland, OR, USA. The energy consumption evaluation showed that this unit has 7.75, 34, 91 kWh/m2 year of heating demand, total site consumption, and primary energy consumption, respectively. A detailed energy analysis was used to explore pathways through which the house could be transformed into a net-zero energy house (NZEH). A model of the eastern unit was calibrated against measured data to perform a detailed energy analysis not only for heating energy, but also including energy used for cooling, water heater, plug loads, electric appliances, and kitchen appliances. Based on this analysis we conclude that two steps are required in order to transform a passive house into a NZEH. First, opportunities for energy conservation measures (ECMs) must be identified. In this study, changes in natural ventilation and occupant behavior were the most effective measures. Modeled implementation of these measures led to energy consumption reduction of 814 kWh/year (∼17%), and 0.1 tons of avoided CO₂/year. The second step was to investigate the most appropriate renewable energy systems; photovoltaic (PV) panels and solar water heating were evaluated. Integrating PV panels over an area of 26 m2 was sufficient to balance the remaining annual energy demand (3936 kWh/year) by producing 4053 kWh/year with a payback period of 15.4-years. On the other hand, using thermal solar water heating was found to reduce the energy consumption by 3047 kWh/year (64%); the remaining energy demand can be overcome by integrating a total of 13 m2 of PV panels. The latter approach has around a 20-year payback period and saves 0.6 tons of CO₂/year. We therefore conclude that the first approach of using PV panels is more cost-effective for transforming a passive house to a ZEH for the climate of the northwest US.
KW - Energy conservation measures
KW - Net-zero energy house (NZEH)
KW - Passive house
KW - Photovoltaic
KW - Solar heaters
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U2 - 10.1016/j.enconman.2018.06.107
DO - 10.1016/j.enconman.2018.06.107
M3 - Article
AN - SCOPUS:85049449476
SN - 0196-8904
VL - 172
SP - 39
EP - 49
JO - Energy Conversion and Management
JF - Energy Conversion and Management
ER -