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Eriksson, M., Akander, J. & Moshfegh, B. (2020). Development and validation of energy signature method – Case study on a multi-family building in Sweden before and after deep renovation. Energy and Buildings, 210, Article ID 109756.
Open this publication in new window or tab >>Development and validation of energy signature method – Case study on a multi-family building in Sweden before and after deep renovation
2020 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 210, article id 109756Article in journal (Refereed) Published
Abstract [en]

Building energy use constitutes a large part of total energy use, both in the European Union and Sweden. Due to this energy use, and the resulting emissions, several goals for energy efficiency and emissions have been set. In Sweden, a large portion of multi-family buildings were built between 1960 and 1980, which have major energy savings potential. The purpose of this paper is further development and validation of previously introduced energy signature method and its inherent parameters. The method was applied on a multi-family building where thermal energy data supplied by the district heating company was available before and after deep renovation. Using IDA ICE, a building energy simulation (BES) software model was created of the building, to aid in validation of the energy signature method. The paper highlighted the accuracy of the proposed energy signature (PES) method and a sensitivity analysis on the inherent parameters have been performed. The results showed new ways of treatment of the thermal energy data and revealed how more information can be extracted from this data.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Energy signature method, Building energy simulation, Validation, Renovation, Multi-family building
National Category
Civil Engineering
Identifiers
urn:nbn:se:hig:diva-31615 (URN)10.1016/j.enbuild.2020.109756 (DOI)000517915800014 ()2-s2.0-85078159553 (Scopus ID)
Available from: 2020-02-03 Created: 2020-02-03 Last updated: 2020-03-26Bibliographically approved
Lundström, L. & Akander, J. (2019). Bayesian calibration with augmented stochastic state-space models of district-heated multifamily buildings. Energies, 13(1), Article ID 76.
Open this publication in new window or tab >>Bayesian calibration with augmented stochastic state-space models of district-heated multifamily buildings
2019 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 13, no 1, article id 76Article in journal (Refereed) Published
Abstract [en]

Reliable energy models are needed to determine building energy performance. Relatively detailed energy models can be auto-generated based on 3D shape representations of existing buildings. However, parameters describing thermal performance of the building fabric, the technical systems, and occupant behavior are usually not readily available. Calibration with on-site measurements is needed to obtain reliable energy models that can offer insight into buildings' actual energy performances. Here, we present an energy model that is suitable for district-heated multifamily buildings, based on a 14-node thermal network implementation of the ISO 52016-1:2017 standard. To better account for modeling approximations and noisy inputs, the model is converted to a stochastic state-space model and augmented with four additional disturbance state variables. Uncertainty models are developed for the inputs solar heat gains, internal heat gains, and domestic hot water use. An iterated extended Kalman filtering algorithm is employed to enable nonlinear state estimation. A Bayesian calibration procedure is employed to enable assessment of parameter uncertainty and incorporation of regulating prior knowledge. A case study is presented to evaluate the performance of the developed framework: parameter estimation with both dynamic Hamiltonian Monte Carlo sampling and penalized maximum likelihood estimation, the behavior of the filtering algorithm, the impact of different commonly occurring data sources for domestic hot water use, and the impact of indoor air temperature readings.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
Augmented stochastic state-space modeling, Bayesian calibration, Building energy performance, Energy models, Iterated Extended Kalman Filtering, Uncertainty, Buildings, Calibration, District heating, Energy efficiency, Extended Kalman filters, Hamiltonians, Hot water distribution systems, Maximum likelihood estimation, Monte Carlo methods, State space methods, Stochastic systems, Uncertainty analysis, Water, Energy model, Extended Kalman filtering, State - space models, Stochastic models
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:hig:diva-31401 (URN)10.3390/en13010076 (DOI)2-s2.0-85077310649 (Scopus ID)
Available from: 2020-01-13 Created: 2020-01-13 Last updated: 2020-01-13Bibliographically approved
Lundström, L., Akander, J. & Zambrano, J. (2019). Development of a space heating model suitable for the automated model generation of existing multifamily buildings: a case study in Nordic climate. Energies, 12(3), Article ID 485.
Open this publication in new window or tab >>Development of a space heating model suitable for the automated model generation of existing multifamily buildings: a case study in Nordic climate
2019 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 12, no 3, article id 485Article in journal (Refereed) Published
Abstract [en]

Building energy performance modeling is essential for energy planning, management, and efficiency. This paper presents a space heating model suitable for auto-generating baseline models of existing multifamily buildings. Required data and parameter input are kept within such a level of detail that baseline models can be auto-generated from, and calibrated by, publicly accessible data sources. The proposed modeling framework consists of a thermal network, a typical hydronic radiator heating system, a simulation procedure, and data handling procedures. The thermal network is a lumped and simplified version of the ISO 52016-1:2017 standard. The data handling consists of procedures to acquire and make use of satellite-based solar radiation data, meteorological reanalysis data (air temperature, ground temperature, wind, albedo, and thermal radiation), and pre-processing procedures of boundary conditions to account for impact from shading objects, window blinds, wind- and stack-driven air leakage, and variable exterior surface heat transfer coefficients. The proposed model was compared with simulations conducted with the detailed building energy simulation software IDA ICE. The results show that the proposed model is able to accurately reproduce hourly energy use for space heating, indoor temperature, and operative temperature patterns obtained from the IDA ICE simulations. Thus, the proposed model can be expected to be able to model space heating, provided by hydronic heating systems, of existing buildings to a similar degree of confidence as established simulation software. Compared to IDA ICE, the developed model required one-thousandth of computation time for a full-year simulation of building model consisting of a single thermal zone. The fast computation time enables the use of the developed model for computation time sensitive applications, such as Monte-Carlo-based calibration methods. 

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
Energy performance modeling, Gray box, ISO 52016-1, Meteorological reanalysis data, Satellite-based solar radiation data, Atmospheric temperature, Buildings, Computer software, Data handling, Energy efficiency, Heating equipment, Hot water heating, Ice, Monte Carlo methods, Solar radiation, Space heating, Energy performance, Reanalysis, Solar radiation data, Climate models
National Category
Energy Engineering
Identifiers
urn:nbn:se:hig:diva-29506 (URN)10.3390/en12030485 (DOI)000460666200153 ()2-s2.0-85060858444 (Scopus ID)
Available from: 2019-02-15 Created: 2019-04-30 Last updated: 2019-08-13Bibliographically approved
Khosravi Bakhtiari, H., Akander, J. & Cehlin, M. (2019). Evaluation of Thermal Comfort in a Historic Building Refurbished to an Office Building with Modernized HVAC Systems. Advances in Building Energy Research
Open this publication in new window or tab >>Evaluation of Thermal Comfort in a Historic Building Refurbished to an Office Building with Modernized HVAC Systems
2019 (English)In: Advances in Building Energy Research, ISSN 1751-2549, E-ISSN 1756-2201Article in journal (Refereed) Epub ahead of print
Abstract [en]

Envelopes with low thermal performance are common characteristics in European historic buildings, causing higher energy demand and insufficient thermal comfort. This paper presents the results of a study on indoor environmental quality (IEQ), with special focus on thermal comfort, in the historic City Hall of Gävle, Sweden, now used as an office building. There are two modern heat recovery ventilation systems with displacement ventilation supply devices. The district heating network heats the building via pre-heat supply air and radiators. Summer cooling comes from electric heat pump ejecting heat into the exhaust ventilation air. A building management system (BMS) controls the heating, ventilation and air-conditioning (HVAC) equipment. The methodology included on-site measurements, BMS data logging and evaluating the occupants’ perception of a summer and a winter period indoor environment using a standardized questionnaire. In conclusion, indoor environmental quality in this historic building is unsatisfactory. Stuffy air, too high, too low and varying room temperatures, lighting problems and noise are constant issues. Although it is equipped with modern ventilation systems, there are still possibilities for improving thermal comfort by improved control strategies, since upgrading the building’s envelope is not allowed according to the Swedish Building Regulations in historic buildings with heritage value.

Keywords
Thermal comfort, historic building, HVAC
National Category
Energy Engineering
Identifiers
urn:nbn:se:hig:diva-29442 (URN)10.1080/17512549.2019.1604428 (DOI)2-s2.0-85064678798 (Scopus ID)
Funder
Knowledge Foundation, 20150133
Available from: 2019-04-05 Created: 2019-04-05 Last updated: 2019-08-16Bibliographically approved
Hayati, A., Akander, J. & Mattsson, M. (2019). Simulation of Ventilation Rates and Heat Losses during Airing in Large Single Zone Buildings in Cold Climates. In: Johansson, D., Bagge, H., Wahlström, Å. (Ed.), Cold Climate HVAC 2018: Sustainable Buildings in Cold Climates. Paper presented at Cold Climate HVAC 2018, The 9th International Cold Climate Conference, Sustainable new and renovated buildings in cold climates, Kiruna, Sweden, 12-15 March 2018. Springer
Open this publication in new window or tab >>Simulation of Ventilation Rates and Heat Losses during Airing in Large Single Zone Buildings in Cold Climates
2019 (English)In: Cold Climate HVAC 2018: Sustainable Buildings in Cold Climates / [ed] Johansson, D., Bagge, H., Wahlström, Å., Springer, 2019Conference paper, Published paper (Refereed)
Abstract [en]

Airing can be a solution to introduce extra ventilation in large single zone buildings, especially where there are large aggregations of people such as churches or atriums. In naturally ventilated domestic and ancient buildings, opening of a window or door can introduce extra fresh air and remove particles and other contaminants emitted from people and other sources such as lit candles in churches. However, the energy use might be an issue in cold climates, where airing might lead to waste of heated air, at the same time as indoor air temperatures can be uncomfortably low. In the present study, the energy loss and ventilation rate due to airing in a large single zone (church) building is investigated via IDA-ICE simulation on annual basis in cold weather conditions. The results can be used in order to prepare airing guidelines for large single zone buildings such as atriums, churches, industry halls and large sport halls. According to the results, one-hour of airing in the studied church building resulted in 40-50 % of exchanged room air and, if practiced once a week, an increase of around 1 % in heating energy.

Place, publisher, year, edition, pages
Springer, 2019
Series
Springer Proceedings in Energy, ISSN 2352-2534
Keywords
Airing (single-sided ventilation), IDA-ICE simulation, Large single zones.
National Category
Building Technologies Energy Systems
Identifiers
urn:nbn:se:hig:diva-26260 (URN)978-3-030-00661-7 (ISBN)978-3-030-00662-4 (ISBN)
Conference
Cold Climate HVAC 2018, The 9th International Cold Climate Conference, Sustainable new and renovated buildings in cold climates, Kiruna, Sweden, 12-15 March 2018
Note

Forthcomming March 2019

Available from: 2018-03-21 Created: 2018-03-21 Last updated: 2019-11-29Bibliographically approved
Björling, M., Mattsson, M. & Akander, J. (2018). Infiltration of Air into two World Heritage Farmhouses in Sweden during Winter Conditions. In: Risto Kosonen, Mervi Ahola, Jarkko Narvanne (Ed.), Roomvent & Ventilation 2018: Excellent Indoor Climate and High Performing Ventilation. Paper presented at Roomvent & Ventilation 2018 'Excellent Indoor Climate and High Performing Ventilation', 2-5 June, 2018, Espoo, Finland (pp. 1079-1084). Helsinki, Finland
Open this publication in new window or tab >>Infiltration of Air into two World Heritage Farmhouses in Sweden during Winter Conditions
2018 (English)In: Roomvent & Ventilation 2018: Excellent Indoor Climate and High Performing Ventilation / [ed] Risto Kosonen, Mervi Ahola, Jarkko Narvanne, Helsinki, Finland, 2018, p. 1079-1084Conference paper, Published paper (Refereed)
Abstract [en]

As a part of an ongoing study, we report measurements of air infiltration during winter conditions into two Decorated Farmhouses of Hälsingland designated as UNESCO World Heritage Sites. In winter these two-storied farmhouses are rarely heated, except for special occasions. In this measurement one farmhouse  was  unheated,  whereas  one  room  was  heated  for  a  brief  period  in  the  other  one.  The observed local mean ages of air measured with tracer gas techniques generally increase with height, both  locally  within  each  room  and  between  floors.  The  average  temperature  and  humidity  also increases from the first to the second floor. The indoor temperature follows the outdoor temperature with a time lag. The differences in water content between inside and outside air correlate with changes of the indoor relative humidity. The correlation is stronger for humidity increase than for humidity decrease, possibly due to moisture absorption by interior text.

Place, publisher, year, edition, pages
Helsinki, Finland: , 2018
Keywords
World Heritage, preservation, moisture, relative humidity, air infiltration, PFT tracer
National Category
Other Civil Engineering
Identifiers
urn:nbn:se:hig:diva-28778 (URN)978-952-5236-48-4 (ISBN)
Conference
Roomvent & Ventilation 2018 'Excellent Indoor Climate and High Performing Ventilation', 2-5 June, 2018, Espoo, Finland
Available from: 2018-12-07 Created: 2018-12-07 Last updated: 2018-12-07Bibliographically approved
Khosravi Bakhtiari, H., Cehlin, M. & Akander, J. (2018). Thermal Comfort in Office Rooms in a Historic Building with Modernized HVAC Systems. In: Kiao Inthavong,Chi Pok Cheung, Guan Yeoh, Jiyuan Tu (Ed.), Proceedings of the 4th International Conference On Building Energy & Environment, COBEE 2018: RMIT University, Melbourne, Australia, Feb 5-9th 2018. Paper presented at 4th International Conference On Building Energy & Environment, COBEE 2018, 5-9 February 2018, Melbourne, Australia (pp. 683-688). Melbourne: Conference On Building Energy & Environment, Article ID 230.
Open this publication in new window or tab >>Thermal Comfort in Office Rooms in a Historic Building with Modernized HVAC Systems
2018 (English)In: Proceedings of the 4th International Conference On Building Energy & Environment, COBEE 2018: RMIT University, Melbourne, Australia, Feb 5-9th 2018 / [ed] Kiao Inthavong,Chi Pok Cheung, Guan Yeoh, Jiyuan Tu, Melbourne: Conference On Building Energy & Environment , 2018, p. 683-688, article id 230Conference paper, Published paper (Refereed)
Abstract [en]

SUMMARY

Envelopes with low thermal performance are common characteristics in European historic buildings, leading to higher energy demand and insufficient thermal comfort. This paper presents the results of a study on thermal comfort in the historic office building of City Hall in Gävle, Sweden. It is equipped with two modern heat recovery ventilation systems with displacement ventilation supply devices in offices. District heating network heats the building via pre-heat supply air and radiators. Summer cooling comes from electric heat pump, rejecting heat into the exhaust ventilation air. A building management system controls HVAC equipment. Methodology includes on-site measurements, data logging on management system and evaluating the occupants’ perception of a summer and a winter period indoor environment using a standardized questionnaire. In conclusion, thermal comfort in this historic building is poor although it is equipped with modern ventilation systems and there should be possibilities for improving comfort, by improved control strategies.

Keywords — Historic Buildings, On-site Measurements, Standardized Questionnaire, Thermal Comfort

Place, publisher, year, edition, pages
Melbourne: Conference On Building Energy & Environment, 2018
National Category
Energy Systems
Identifiers
urn:nbn:se:hig:diva-26550 (URN)978-0-646-98213-7 (ISBN)
Conference
4th International Conference On Building Energy & Environment, COBEE 2018, 5-9 February 2018, Melbourne, Australia
Available from: 2018-05-07 Created: 2018-05-07 Last updated: 2018-06-05Bibliographically approved
Akander, J., Cehlin, M. & Moshfegh, B. (2017). Assessing the Myths on Energy Efficiency When Retrofitting Multifamily Buildings in a Northern Region (1ed.). In: Ali Sayigh (Ed.), Sustainable High Rise Buildings in Urban Zones: Advantages, Challenges, and Global Case Studies (pp. 139-161). Cham: Springer Publishing Company
Open this publication in new window or tab >>Assessing the Myths on Energy Efficiency When Retrofitting Multifamily Buildings in a Northern Region
2017 (English)In: Sustainable High Rise Buildings in Urban Zones: Advantages, Challenges, and Global Case Studies / [ed] Ali Sayigh, Cham: Springer Publishing Company, 2017, 1, p. 139-161Chapter in book (Other academic)
Abstract [en]

In the light of EU’s requirements to achieve a major cut in energy use by 2050, Sweden has the same target. The built environment must by 2020 reduce energy use by 20 and 50 % by 2050. The size of the future building stock will naturally increase and regardless of how energy efficient future buildings will be, the energy performance of the old stock must be improved in order to reach those goals. In major renovation projects involving multifamily buildings in large residential areas in the cities, 50 % reduction can be achieved. This is cost-effective and profitable even if the rent is increased.

Gävleborg is a sparse region in the North, with few cities. Multifamily buildings are generally much smaller than in large cities and owners are reluctant to impose changes that increase rents due to the housing situation in the region. In consequence, the Regional Council and the University of Gävle set out to assess the potential and feasibility of reducing energy use and carbon dioxide emissions in this region’s multifamily buildings. Eleven real buildings were investigated, each having various ownership forms, different technical attributes and heating sources. Energy audits and measurements were conducted to assess the condition of each building. Performances of the buildings and proposed improvements were simulated with building energy simulation programs, whilst life cycle cost analyses were conducted to study viability. Carbon dioxide emission (CO2) reductions were estimated for each improvement.

Based on the results, a concluding discussion is made on whether or not some myths on energy use and retrofitting are true. The following is concluded: It is possible to reach a 50 % reduction, but it is not economical with the costs involved and with today’s energy prices and moderate price increase over time.

Retrofitting or improvements made in the building’s services systems (HVAC) are more economical than actions taken to improve performance of building by constructions. HVAC improvements give about 20 % reduction in energy use. However, mechanical ventilation systems with heat recuperation are not economical, though these may or may not substantially reduce use of thermal energy.

Solar energy is, despite the latitude of the region, economically viable—especially PV solar energy. Photovoltaic panels (PVs) are becoming viable—the combination of PVs and district heating is beneficial since saving electricity is more important than thermal energy in district-heated areas.

Place, publisher, year, edition, pages
Cham: Springer Publishing Company, 2017 Edition: 1
Keywords
Retrofit, Multifamily buildings, Energy savings
National Category
Energy Systems
Identifiers
urn:nbn:se:hig:diva-23209 (URN)10.1007/978-3-319-17756-4_8 (DOI)2-s2.0-85028882688 (Scopus ID)978-3-319-17755-7 (ISBN)978-3-319-17756-4 (ISBN)
Projects
EKG-f
Funder
Swedish Energy Agency
Note

Funders of the EKG project: Swedish Energy Agency, Regional Council of Gävleborg and University of Gävle. 

Available from: 2017-01-02 Created: 2017-01-02 Last updated: 2018-03-13Bibliographically approved
Steen Englund, J., Akander, J., Björling, M. & Moshfegh, B. (2017). Assessment of Airflows in a School Building with Mechanical Ventilation Using Passive Tracer Gas Method (1ed.). In: Sayigh, Ali (Ed.), Mediterranean Green Buildings & Renewable Energy: Selected Papers from the World Renewable Energy Network’s Med Green Forum: (pp. 619-631). Springer
Open this publication in new window or tab >>Assessment of Airflows in a School Building with Mechanical Ventilation Using Passive Tracer Gas Method
2017 (English)In: Mediterranean Green Buildings & Renewable Energy: Selected Papers from the World Renewable Energy Network’s Med Green Forum / [ed] Sayigh, Ali, Springer, 2017, 1, p. 619-631Chapter in book (Refereed)
Abstract [en]

The focus of this study is to assess the airflows in a school building built in 1963 in Gävle, Sweden, which is subject to energy conservation measures (ECMs) in a forthcoming renovation. Today, the school building is mainly ventilated by several mechanical ventilation systems, which are controlled by a constant air volume (CAV) strategy. Schedules and presence sensors impose a high operation mode during the day and a low operation mode at night, on weekends and on holidays. The homogeneous tracer gas emission method with passive sampling is used to measure the average local mean age of air (τ) during different operation modes. Temperature, relative humidity and CO2 concentration are simultaneously measured. The calculated relative uncertainty for the average local mean age of air in every measured point is approx. ±20 %. The results during low operation mode show an average value of τ of approx. 8.51 h [corresponding to 0.12 air changes per hour (ACH)], where τ in various zones ranges between 2.55 and 16.37 h (indicating 0.06–0.39 ACH), which is related to the unintentional airflow in the school. The results during mixed operation mode show an average value of τ of approx. 4.60 h (0.22 ACH), where τ in various zones ranges between 2.00 and 8.98 h (0.11–0.50 ACH), which is related to both unintentional and intentional airflows in the school. Corridors, basement and attic rooms and entrances have lower τ compared to classrooms, offices and other rooms. High maximums of the CO2 concentration in some rooms indicate an imbalance in the mechanical ventilation systems. During a regular school week of mixed operation, which includes both high and low operation modes, it is found that mainly the low operation modes show up in the results. The dynamics of the highly varying airflows in the building cannot be identified using the passive sampling technique.

Place, publisher, year, edition, pages
Springer, 2017 Edition: 1
Keywords
Homogeneous tracer gas emission technique, Local mean age of air, Air change rate, Air leakage, School building
National Category
Energy Systems
Identifiers
urn:nbn:se:hig:diva-24006 (URN)10.1007/978-3-319-30746-6_47 (DOI)2-s2.0-85029047826 (Scopus ID)978-3-319-30745-9 (ISBN)978-3-319-30746-6 (ISBN)
Note

Entire publication doi: 10.1007/978-3-319-30746-6

Available from: 2017-05-12 Created: 2017-05-12 Last updated: 2018-03-13Bibliographically approved
Akander, J. & Morberg, Å. (2017). Sustainability of world heritage: who inherits the ownership of decorated farmhouses of Hälsingland? (1ed.). In: Fagerström, Arne and Cunningham, Gary M. (Ed.), A Good Life for All: Essays on sustainability celebrating 60 years of making life better (pp. 139-161). Mjölby: Atremi AB
Open this publication in new window or tab >>Sustainability of world heritage: who inherits the ownership of decorated farmhouses of Hälsingland?
2017 (English)In: A Good Life for All: Essays on sustainability celebrating 60 years of making life better / [ed] Fagerström, Arne and Cunningham, Gary M., Mjölby: Atremi AB , 2017, 1, p. 139-161Chapter in book (Other academic)
Abstract [en]

This chapter discusses sustainability of Sweden’s most recent World Heritage (WH) site, the Decorated Farmhouses of Hälsingland. A general overview presents what WH is, why it is special and why it should be preserved for future generations. The views of WH farm owners on managing a WH site and how they feel about the task have been assessed. WH must be preserved for future generations and it is necessary for the farms to interact sustainably with their local communities. Most WH farms are privately owned and have been within the same family for centuries. Will this continue in the future or are there problems with succession?

Place, publisher, year, edition, pages
Mjölby: Atremi AB, 2017 Edition: 1
Keywords
Decorated farmhouses of Hälsingland, world Heritage, sustainability
National Category
Other Social Sciences
Identifiers
urn:nbn:se:hig:diva-23771 (URN)978-91-7527-174-3 (ISBN)
Available from: 2017-03-18 Created: 2017-03-18 Last updated: 2018-03-13Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9076-0801

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